Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

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Transcript of Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

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PERSHINGA History of

the Medium Tank T20 Series

by

R. P. Hunnicutt

Line Drawingsby

D. P. Dyer

Color Drawingsby

Uwe Feist

Forewordby

Colonel Robert J. Icks, AUS-Retired

FEIST PUBLICATIONS

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COPYRIGHT ©1971 BY R. P. HUNNICUTT

ALL RIGHTS RESERVEDNO PART OF THIS BOOK MAY BE REPRODUCEDIN ANY FORM WITHOUT WRITTEN PERMISSIONFROM THE PUBLISHERS.FIRST EDITION

PRINTED IN U.S.A. - PACIFIC ROTAPRINTING COMPANYPublished in the United States by FEIST PUBLICATIONS

2827 7th Street • Berkeley • California 94710

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CONTENTS

Foreword 5Introduction 6

PART I A NEW TANK FOR THE TROOPS 7

Action at Remagen 9The Zebra Mission 13Pershings to Okinawa 41

PART II THE DEVELOPMENT HISTORY 47

Requirement for a New Tank 49The T20 and T20E3 52The T22 and T22E1 62The T23, T23E3, and T23E4 72The T25 and T26 94The T25E1, T26E1, and M26 (T26E3) 104The M45 (T26E2), T26E4, and T26E5 134The M26El, M26E2, and M26A1 150Vehicles based on the M26 158

PART III FINAL SERVICE 173

Korea 175Conclusion 194

PART IV REFERENCE DATA 197

Pershing, Panther, and Tiger I, A Comparison 199Vehicle Data Sheets 203Weapon Data Sheets 227

References and Selected Bibliography 238Index . . 239

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ACKNOWLEDGEMENTS

The material gathered into this book came fromso many sources that it would be impossible to namethem all. However, particular thanks must go toColonel Robert J. Icks as well as Colonel G. B. Jarrettand the the staff of the Ordnance Museum at Aber-deen Proving Ground. Both located invaluable mate-rial. Mrs. Forst and her group at the APG TechnicalLibrary found most of the test reports on the vehi-cles. Carl Rasmussen, Daniel F. Smith, RobertThibodeau, and William Russell of the Army TankAutomotive Command at Detroit Arsenal providedmost of the background for the development history.This was also aided by William Tauss, who was thewartime project engineer on the M26. Description ofthe Pershing's introduction to combat would havebeen impossible without the detailed notes taken onthe spot by Lt. Colonel Elmer Gray during the Zebramission. His previously unpublished photographswere used to illustrate that section. The detailedphotographs of the Pershing production came fromGM Photographic by way of Dale McCormick atGeneral Motors. Mrs. Traxler of the Army Photo-graphic Agency located most of the Korean photos in

addition to those of the Remagen crossing. JudgeJohn Grimball, who as a young lieutenant com-manded the first Pershing platoon in action, correctedmuch of the information on the Remagen attack.Colonel Peter Hordern was most helpful in makingavailable the resources of the Royal Armoured CorpsTank Museum at Bovington Camp, England. Othercontributors included George Schneider of the PattonMuseum at Fort Knox, Joseph Avery of the NationalArchives, Brigadier General Joseph Colby, 1st Lt.Dwight McLemore, Paul van Thielen, Peter Chamber-lain, John Kennon, L. R. "Slim" Price, and JohnnyDay.

Uwe Feist and Phil Dyer labored many hours toachieve the maximum accuracy possible in their draw-ings. Both discovered and called the author's atten-tion to some previously undetected variations amongthe experimental vehicles. Finally, I must thank mywife Susan for the long hours in typing and retypingthe manuscript, despite a complete lack of interest inthe subject material. All of these contributions wereessential to the books completion.

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FOREWORD

Reading this history of the development of thePershing was a most pleasant experience. Most of theindividuals named were familiar, including that of Lt.Colonel Elmer Gray who went through the FortCuster Separation Center with me late in 1945.

Although a transfer from Aberdeen ProvingGround to the Office Chief of Ordnance — Detroit inFebruary 1943 took me away from direct knowledgeof the T20 series development, friends kept me in-formed, The first T26E1 was undergoing tests atAberdeen not long after the all weather Munson TestCourse was completed. Knowing that the course,named after a fine young officer, First LieutenantMax Munson, who had been killed during a vehicletest about two years earlier, was designed by me withthe assistance of my engineering officer, First Lieu-tenant William Brosha, my successor, Colonel EdwardE. Gray, invited me to Aberdeen in May 1944 to seethe finished course and to see the T26E1 in opera-tion.

After touring the course in a jeep with ColonelGray, Captain Gifford Griffin took me for a ride inthe T26E1 over the varied terrain of the ChurchvilleTest Course, which my staff and I also had laid outduring my tour of duty at Aberdeen. It was animpressive tank. Compared with the M4, the ride wasfirm and smooth. The engine power was adequate andthe transmission smooth.

But impressive as the ride was, it was not asimpressive as its main armament. I had fired tankweapons many times, but never any of this caliber.Bore sighted by Johnny Day and "Slim" Price, bothAutomotive Division armament specialists, the 90mm rounds hit exactly where they were aimed andgave one confidence that we soon would have a tankequal to anything the Germans had to offer.

That they were late in arriving in the combatzones can be blamed on a few Ground Forces andArmored Board officers. Most such officers werededicated, but a few had closed minds and lackedimagination. Unfortunately, those were the ones whowere in positions of authority. Had it not been forconcerned Ordnance officers who were determined toprovide a better tank for the troops and went overthe" heads of the obstructionists to have them over-ruled, the development which led to the Pershing andthe shipment of the few which eventually got to com-bat zones probably would not have taken place.

Until now, no one has written this completehistory. There are many reasons for this. As theauthor, Mr. R. P. Hunnicutt points out, it has takenten years for him to piece it all together. He is to becommended for having had the patience to do so.Armor enthusiasts everywhere should welcome thismost complete and authentic study of an interestingphase of World War II history.

Robert J. IcksColonel AUS - Retired

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INTRODUCTION

Much has been written, since the end of WorldWar II, on the amazing technical achievements in thedevelopment of German armored vehicles. Under thepressure of war, a wide variety of projects were ini-tiated. A few were wildly impractical, but others re-sulted in designs which still remain as the basis formodern weapon development. Some of the new Ger-man tanks and self-propelled guns were introducedinto battle when hardly past the prototype stage. Al-though they suffered numerous teething troubles, aprofound impression was made upon the troopsunfortunate enough to appose them. The publicityresulting from these actions, plus the availability ofGerman development records after the cessation ofhostilities, contributed to the intense interest in thesubject. Even a quarter of a century later, new ma-terial is still being unearthed about the German war-time projects. In comparison, a much smaller amountof information has been published regarding theAllied development effort. This has been true, partlybecause of continuing security restrictions, and partlydue to the difficulty in sorting the necessary materialfrom the mountains of documents and test reportsprepared during this period. Wholesale destruction ofmany such documents before declassification alsocontributed to the research problem.

Starting late compared to the Germans, theAllied research and development effort was no lessintense and produced results no less remarkable. Theobjective of this book is to trace the course of oneAmerican development program, that of the T20 me-dium tank series, from the beginning to its conclusionin the postwar period.

The workhorse of American armored troopsthroughout the war was the M4 medium tank, nick-named General Sherman. The Sherman, however, wasa prewar design modified in light of the British battleexperience. It proved to be extremely adaptable,serving throughout the war and long into the postwarera. Such long life resulted from its basic design flexi-bility, enabling it to absorb the many changes re-quired to compete with newer vehicles. The source ofmany modifications used to modernize the Shermanwas the new tank development program initiatedearly in 1942. With the Sherman in full production,attention was turned to the development of an im-proved tank using the latest components and designtechniques. Funds were available to investigate a widevariety of weapons, power trains, and suspensions.

About this time, remarkable results were being ob-tained using an electric drive in the heavy tank T l E land a natural result was to adapt it for use in the newmedium tank. An interesting parallel is noted herewith the German development program where Dr.Ferdinand Porsche was using an electric drive in hisversion of the early Tiger and its descendent the Ele-fant self-propelled gun. Although the electric driveoffered unique handling characteristics and excellentmaneuverability, neither the American nor the Ger-man versions found favor with the combat troops.Lighter weight, less complex mechanical or hydraulicdrives were preferred by the men who had to usethem.

American tank doctrine required a highly mobilemedium tank suitable for the exploitation role, butwith sufficient firepower and protection to enable italso to operate in support of infantry. The T20 seriessought to meet these objectives with considerableimprovement over the Sherman. Unlike the prevailingArmy Ground Force doctrine, the Armored Forceand the Ordnance Department believed that the bestantitank weapon was another tank. Following thisline, the T20s were armed, first with the new 76 mm,and later the 90 mm high velocity guns. The latteroffered an excellent balance of firepower, mobility,and protection in the T25E1 with their importancearranged in that order. Later efforts to match heavyGerman armor without increasing the engine powerreduced the mobility of the T26 models. However,the troops in Europe, engaged by the high poweredGerman tank and antitank guns, were calling for moreand more armor protection. As a result, the T26E3was standardized as the M26 (General Pershing) andeven heavier armor protection was planned. for theT26E5. With the standardization of the Pershing,there was no further interest in the T25E1 and theopportunity was lost to provide a successor to theSherman with superior firepower and mobility.

The research for this volume spanned a ten yearperiod involving travel to many parts of the UnitedStates and England. On many occasions when aparticular subject seemed exhausted and nothingmore was available, completely new material wouldturn up, in some cases reversing earlier conclusions.No doubt this will continue after publication. Anysuch new material or corrections of the present vol-ume will be greatly appreciated by the author.

R. P. HunnicuttBelmont, California

March 1971

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PART I

A NEW TANK FOR THE TROOPS

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Pershings from Lieutenant Grimball's platoon of Company A, 14th Tank Battalion, 9th Armored Division wait for attackorders on March 1st, 1945 in a field outside Vettweiss, Germany.

ACTION AT REMAGEN

In the late morning of March 7th, 1945, thespearhead of the 9th Armored Division reached theheights overlooking Remagen on the western bank ofthe Rhine River. The troops from the 27th ArmoredInfantry and the 14th Tank Battalion had beenpushing toward the Rhine ever since the offensiveopened with the crossing of the Roer River on themorning of February 28th. During the first week ofthe advance, the leading tanks were the familiarShermans widely used by all units in the U.S. Army.However , as the ha l f - t r acks of LieutenantTimmerman's Company A, 27th Armored Infantrypulled out on the morning of the 7th, they wereaccompanied by a new silhouette, unlike anypreviously seen in American service. These tanks werewide and low and carried a massive turret mounting along barreled cannon with a muzzle brake. This wasthe T26E3 (General Pershing), at that time classifiedas a heavy tank. The Pershing weighed approximately

45 tons and carried a 90 mm gun. The vehicle wasdesigned to provide firepower and protection com-parable to that of the German Tiger I.

Although a platoon of Pershings had been withCompany A, 14th Tank Battalion since the crossingof the Roer River, little opportunity had arisen fortheir employment. Because of their greater weightand width, it was difficult for them to cross thenarrow bridges spanning the numerous streams in thisarea. It was noted early in the drive that the widet racks of the Pershings often damaged theprefabricated bridges installed by the Corps ofEngineers. The necessary repairs often delayed thetroops following behind. As a result, the Pershingswere often forced to wait until other elements of thecolumn had crossed over. By the morning of March7th, most of these obstacles had been passed and forthe final thrust toward Remagen, the platoon ofPershings was placed in front with Company A of the

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Sergeant Key's Pershing knocked out by two heavy high explosive shells. The commander's vision cupola was blown off andcan be seen on the ground beside the tank.

27th Armored Infantry. The five tank platoon,commanded by 1st Lieutenant John Grimball, ofColumbia, South Carolina, had been reduced to fourby this time.

The five T26E3s originally assigned to Grim-ball's platoon were serial numbers 22, 27, 28, 35 and39. On the night of March 1st, Pershing number 22was struck by two heavy high explosive shells whileparked near a road junction east of the Roer River.The first shell, estimated as 15 cm in caliber, hit nearthe right rear sprocket damaging the running gear andstarting a fire in the engine compartment. The crew,led by Platoon Sergeant Chester Key, dismounted tofight the fire when a second shell struck the turretjust to the rear of the tank commander's hatch. Ser-geant Key was instantly killed. The commander's cu-pola was blown off and landed 25 feet away. Laterexamination revealed that all but four of the turretmounting bolts were sheared. The vehicle was stillbeing repaired on March 7th. An earlier casualtyamong Grimball's Pershings occurred when number27 broke a piston shortly after crossing the RoerRiver. However, the engine was replaced and the tankreturned to duty on March 5th, two days before theattack on Remagen.

When scouts from the leading infantry half-trackreached the crest overlooking the Rhine Valley, theywere astonished to see the Ludendorf railway bridgestill intact, spanning the river on the other side of thetown. Lieutenants Timmerman and Grimball came upto see for themselves and transmitted the informationto the Task Force Commander, Lieutenant ColonelEngeman. When the discovery was reported toBrigadier General Hoge of Combat Command B, heordered a rapid advance into the town by all troopsand directed that a major effort be made to seize thebridge intact. Lieutenant Timmerman's infantrymoved down the hill into Remagen with the tanksfollowing along the road. Only minor opposition wasencountered. A machine gun opened up on theinfantry in the main square, but was quickly silencedby 90 mm fire from two of Lieutenant Grimb all'stanks.

The push continued through the town untilabout 1400 hours when the tanks and infantryapproached the western edge of the bridge. At thistime, the German demolition team blew a large holein the approach causeway blocking the entrance tothe bridge for the tanks. On orders from ColonelEngeman, Lieutenant Grimball covered the bridge

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The western end of the Ludendorf bridge on March 9th, two days after its capture. The hole blown in the approach causewayhas been bridged and prisoners are being brought back across the Rhine. The eastern end of the bridge is shown below.

with machine gun fire to keep the Germans fromusing it and to interfere with their demolitionprocedures. As Timmerman and Lieutenant Mott ofthe Engineers were organizing their men for thecrossing, the Germans set off an emergencydemolition charge two-thirds of the way across thebridge. The huge structure lifted, timbers, dust andthick smoke mixed in the air, but it settled backin tac t although badly damaged.

Observing the movement of the infantry up tothe bridge, the German machine gunners raked theapproach from the two towers at the western end.Grimball's tank slammed a 90 mm high explosiveshell into one of the towers and the machine gun fireslackened. The infantry began to move across thebridge cleaning out the towers as they went. Abouttwo-thirds of the way across, they were taken underfire by snipers from a half submerged barge about200 yards up stream. A Sherman tank, which hadnow joined the Pershings, blasted the barge with its75 mm gun. As the engineers cut away the demolitioncharges, the infantry completed their crossing. Un-aware of the situation, a German train steamed into

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The tanks from Lieutenant Grimball's platoon being loaded onferries constructed from bridge pontons on March 12, 1945.

The bridge area was still under enemy artillery fire as theferries were pushed across the Rhine.

view on the far side of the river and was enthusias-tically destroyed by the tanks, exploding the boilerand scattering the troops which poured out of thecars.

The bridgehead on the eastern side of the riverwas secured by the infantry and feverish efforts fol-lowed to fill the hole in the approach causeway topermit supporting tanks to cross over. This work wascompleted by nightfall and during the night two pla-toons of Shermans and some tank destroyers crossedto reinforce the infantry. Because of their widerdimensions and heavier weight, the Pershings werenot permitted to cross the damaged bridge. Five dayslater, on March 12th, barges were improvised byjoining five bridge pontons and the Pershings wereferried to the eastern shore.

The 3rd Armored Division first introduced thePershing into action with the attack across the RoerRiver ten days before Remagen. However, the seizureof the vital bridge on the Rhine was of greater signi-ficance as far as the course of the war was concerned.Combat Command B of the 9th Armored Divisionwas also the first to use the Pershing in a full platoon.The other organizations equipped from the originalshipment distributed their tanks in ones and twos toseparate companies, but in the 14th Tank Battalionall five Pershings were concentrated in one platoonunder Lieutenant Grimball.

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T26E3, serial number 55, shown here is representative of the early production Pershings. This particular tank was under testat Aberdeen Proving Ground.

THE ZEBRA MISSION

The full story of the Pershing's introduction tocombat must be traced back to the United States inthe fall of 1944. Production of the T26E3 was juststarting at the Fisher Tank Arsenal and Major GeneralBarnes, Chief of Ordnance Department Research andDevelopment, was convinced that these vehicles wereurgently needed in the European Theater of Opera-tions. He proposed that of the first 40 vehicles pro-duced, 20 should be sent directly to Europe andsimultaneously 20 to Fort Knox for tests by theArmored Board. Army Ground Forces objected tothis procedure, saying that the shipment to Europeshould be delayed until the tanks were tested andapproved by the Armored Board. Convinced thattime was too short for such delays, General Barnesthreatened to carry his argument to General Marshall,if necessary. Major General Russell Maxwell, AssistantChief of Staff, G4, agreed with his argument and 20T26E3s were shipped to Antwerp, Belgium in Jan-uary 1945.

To assist in the rapid introduction of the Per-shing as well as several other hew weapons, GeneralBarnes led a technical mission to Europe. This mis-sion, code name Zebra, arrived in Paris on February9th, 1945. Besides General Barnes, the group in-cluded Colonel Joseph Colby and Captain Elmer Grayof the Tank Automotive Command, Colonel GeorgeDean of the Army Ground Forces New DevelopmentsDivision, Captain Gifford Griffin from AberdeenProving Ground and two civilians. The latter were W.A. (Bill) Shaw, a representative from the Fisher TankArsenal, who had been with the T26E3 since its ori-ginal conception, and L. R. (Slim) Price from Aber-deen Proving Ground, an expert on the 90 mm gunmounted in the Pershing. After a meeting with Gen-eral Eisenhower, it was decided to get the 20 tanksinto action as soon as possible and they were allassigned to the 12th Army group where General Brad-ley sent them to First Army, dividing them equallybetween the 3rd and the 9th Armored Divisions.

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A Pershing from the first shipment being loaded aboard amodified M25 tank transporter at Antwerp, Belgium, 9 Feb-ruary 1945.

After conferences with General Barnes andColonel Colby, Captain Gray was told that he had theball and to carry it. With these instructions, Gray andhis team headed for Antwerp on February 11, 1945.Captain Griffin had been assigned to accompany theshipment of tanks by sea with definite orders that allboxes and equipment were to be unloaded at theport, but nothing was to be turned over to the Trans-portation Corps for movement. When Gray arrived atAntwerp, his worst fears were realized. CaptainGriffin had been outranked and all of the boxedgoods had been loaded into 15 freight cars with thepromise that they would travel as one train. However,in line with previous experience, the cars werequickly scattered, requiring the assignment of aTransportation officer to track them down. After twoweeks of hard work, this officer managed to round upall 15 cars and escort them to the parts depot.

Antwerp was being heavily bombarded by theGerman V-l "buzz bombs" during this period. Toavoid possible loss, the tanks and equipment wereloaded on modified M25 tank transporters and movedto Brussels. These transporters had the trailer rein-forced to handle the Pershing's 45 tons and rampswere added over the rear tires to permit loading thewider tanks. In Brussels, Captain Gray received wordto meet General Barnes and Colonel Colby at EagleHeadquarters in Namur, France. This was the 12thArmy Group Headquarters of General Omar Bradley.Gray headed for the rendezvous, but had to continueon to First Army Headquarters at Spa where Barnesand Colby were conferring with General Hodges.When he arrived, Gray received orders from ColonelColby to move the tanks immediately to Aachen,Germany, where the 559th Heavy Maintenance TankCompany would prepare them for combat. Returningto Brussels, the transporters were checked and pre-pared for the long road trip. One of Captain Gray'sless orthodox preparations involved removing the en-gine mufflers thus insuring maximum power for a fastpassage. A day was consumed with the preparationsand obtaining road clearances for the convoy throughthe British sector. Some confusion was associatedwith the latter and the Military Police attempted tostop the convoy when it moved out on Saturdaymorning, February 17th. The details of the confron-tation are somewhat clouded, but rumor has it thatthe M.P.s, led by a major, were threatened with beingrun over by the loaded tank transporters. Whateverthe truth of the matter, the convoy arrived at itsdestination at 1700 hours the same day, as Graystates in his report, "without mishap or misgivings."It had been raining continuously and was bitterlycold, but in spite of the weather, members of the559th started to prepare the tanks for combat.

General Barnes and Colonel Colby had made awise selection in the choice of Captain Gray for thisproject. The success of the rapid movement fromAntwerp to Aachen and of many operations to followwere due in great measure to his efforts. His skill incutting red tape and getting a job done had beenproven during an earlier mission introducing heavyartillery pieces in the summer of 1944. Although El-mer Gray insists that he went through channels, byhis own admission these channels were considerablywider and deeper following his passage.

At Aachen, the crews assigned to ten of thetanks had arrived from the 3rd Armored Division andclasses were formed for their instruction. CaptainGray instructed the group on elementary mechanicsand the components of the vehicle, while CaptainGriffin covered operating procedures. Slim Price helda class on gunnery for the tank commanders, gunnersand loaders.

Wreckage of a German V-l in "buzz bomb alley".

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The tanks were checked out and the crews trained despite thecold, wet weather at Aachen. The low temperature is apparentfrom the appearance (above) of the General Motors representa-tive, Bill Shaw, taken during the training program.

The tall officer in the photograph below is Lieutenant JohnGrimball who led the Pershings at Remagen.

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Gunnery training at Aachen introduced the veteran crews to the 90 mm gun. The flash and smoke were much greater with the90 than with the smaller tank guns.

By February 20th the crews from the 3rd Ar-mored Division had completed their schooling andtheir tanks had been checked out mechanically. How-ever, as yet the guns had not been boresighted andtest fired. Slim Price selected a firing range and super-vised the crews in this work. Each tank crew fired 28rounds to thoroughly familiarize themselves with theweapon. In the meantime, crews had been moving infrom the 9th Armored Division to receive theremaining ten tanks. These men underwent a similartraining program while their tanks were being brought

up to combat readiness. In addition, schools wereheld for the maintenance battalions in both the 3rdand 9th Armored Divisions.

Through all of his instruction on the 90, SlimPrice emphasized the importance of properlyboresighting the weapon. The gun was extremelyaccurate, but this advantage could easily be lost bycareless boresighting or failure to minimize the effectof backlash in the traverse and elevation gears. Pricechecked the original 20 tanks after boresighting bytheir crews and found only one met his standard.

Even with the muzzle brake acting as a deflector, smoke and dust created problems by obscuring the target during firing ofthe 90. Note the empty shell case on the ground from the previously fired round.

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The 3rd Armored Division retained the 1942 organizational structure with two armored regimentswhile the 9th Armored Division followed the 1943 tables of organization replacing the two regiments withthree tank battalions.

After correcting the other 19 tanks, he demonstratedthe accurate shooting possible with the 90. Hismethod, which he passed on to his students was notto just aim at the enemy tank, but to aim at a particu-lar spot on that tank and his demonstration showed itwas possible to hit that spot. Later in the mission heimpressed some of Patton's tank crews by using Ger-man helmets as targets and picking them off withsingle shots from the 90 at a range of 625 yards. Suchperformance quickly overcame any objections thatveteran tankers might have had to receiving gunneryinstruction from a civilian. In fact, the veteransrapidly duplicated his markmanship once they got the"feel" of the weapon.

During the initial test firing, a malfunction oc-curred, typical of those which plague equipment stillunder development. When firing the first round froma cold gun, the recoil was insufficient to engage thecam designed to open the breech and eject the emptyshell case. As the gun warmed up, the length of recoilincreased and the breechblock operated properly.However, such a failure on the first shot could be amatter of life or death for the tank crew if that shotmissed or more than one enemy tank was present.The time required to manually open the breech andeject the shell case would give the enemy ample time

to return the fire. The problem arose from the factthat the cam was designed for the 90 mm gun asmounted in the T26E1. This gun was not fitted witha muzzle brake. The addition of the muzzle brake onthe T26E3 reduced the recoil to the point where itwould not trip the cam if the gun was cold. Gray andPrice solved the problem by removing 1/2 inch fromthe cam without changing its contour. The. breechblock would then operate under any firing condi-tions.

Boresighting and test firing were completed onFebruary 23rd and the tanks were ready for combat.

On February 25th the 3rd Armored Division wascommitted to battle, attacking across the Roer River.Three days later the 9th followed. During this periodthe Ordnance team made their home with the 3rdArmored Division's maintenance battalion in Düren,Germany and from there followed the tanks into ac-tion, supervised necessary repairs, and recorded theirperformance.

Captain Gray drove from Düren to Elsdorf onthe 28th to check on a 3rd Armored T26E3 report-edly knocked out two days before. This tank, thefirst lost in action, proved to be serial number 38assigned to F company, 33rd Armored Regiment. ThePershing was named "Fireball" with the name painted

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ZEBRA MISSIONAssignment of 20 T26E3 Tanks

3rd Armored Division32nd Armored Regiment 33rd Armored Regiment

Serial Registration Company Serial Registration CompanyNo. No. No. No.26 30119836 E 24 30119834 D31 30119841 H 25 30119835 H33 30119843 G 37 30119847 I34 30119844 I 38 30119848 F36 30119846 D 40 30119850 E

9th Armored Division14th Tank Battalion 19th Tank Battalion

Serial Registration Company Serial Registration CompanyNo. No. No. No.

22 30119832 A 23 30119833 C27 30119837 A 29 30119839 B28 30119838 A 30 30119840 A35 30119845 A 32 30119842 B39 30119849 A 41 30119851 C

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The first loss. T26E3 number 38, "Fireball", knocked out by a Tiger at Elsdorf. The 8.8 cm hole through the machine gunport can be seen above and in closeup below. The round objects on the front armor are the belly escape hatch covers.

on both sides of the vehicle. The tank had been posi-tioned behind a roadblock to watch for enemy move-ment. This turned out to be a poor location with thefires burning in the vicinity. In the darkness, flamesfrom a burning coal pile silhouetted the turret whichwas exposed above the road block. A German Tigertank, concealed behind the corner of a building, firedthree times at the turret at a range of about 100yards. The first 8.8 cm shot penetrated through thecoaxial machine gun port, spun around inside the tur-ret killing the gunner and the loader. The second hitthe muzzle brake and the end of the gun tube jarringoff the round that was in the chamber. The dischargeof this shell caused the barrel to swell at about thehalfway point even though the projectile went on outthe tube. A third shot glanced off the upper right-hand side of the turret tearing away the cupola hatchcover which had been left open. The Tiger thenbacked up, immobilizing itself on a pile of debri andwas abandoned. The loader of the Tiger was latercaptured and confirmed that his tank had done thefiring.

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The Ordnance team surveys the damaged "Fireball". The bulgein the 90 mm gun tube is visible where the paint has spalledoff and the remains of the smashed coaxial machine gun are onthe right fender. The scuff mark where an 8.8 cm projectilebounced off the turret can be seen above and in closeup at theleft. The damaged muzzle brake is at the left below and theleft side name marking is shown below.

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"Fireball" repaired and ready to return to action on March7th. Note that the coaxial machine gun port has been repairedby welding and a new gun tube is installed.

"Fireball" was promptly avenged the followingday when Pershing number 40 assigned to CompanyE 33rd Armored Regiment, knocked out and burneda Tiger I and two Panzer IVs, also at Elsdorf. Fourshots were fired and registered on the Tiger at a rangeof approximately 900 yards. The first, a T30E16HVAP projectile, destroyed the final drive. Thesecond, a T33 shot, hit the bottom of the gunmantlet next to the hull penetrating the turret cau-sing an explosion. Two other hits by high explosivewere ineffective. The two Panzer IVs were knockedout and burned at a range of 1200 yards with oneround each of T33, but an additional two rounds ofhigh explosive were used to destroy the crews as they

escaped. Another Panzer IV was later destroyed bythis crew during the drive to Cologne.

The damaged "Fireball" was immediately eva-cuated to the division maintenance battalion at Dürenfor repairs. A truck was dispatched to the 310thOrdnance Battalion which was handling the spareparts brought along on the mission. Unfortunately,these parts did not include 90 mm guns and "Fire-ball's" cannon was damaged beyond all hope. Aphone call to Paris saved the situation by obtaining aspare 90 mm gun tube from an M36 tank destroyer.Repairs were then completed with the shot holeswelded up and the new parts installed. "Fireball" wasrecommitted to action on March 7th.

Fireball's avenger, Pershing number 40, which destroyed a Tiger I and two Panzer IVs also at Elsdorf. The tank commander issecond from the left.

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Slim Price, at the left, and the Pershing tank commander standin front of the Tiger knocked out at Elsdorf. The 90 mm holethrough the lower gun shield can be seen just to the left of thetank commander's face. A closeup of this hit is shown below.Below at the right is a view of the hit on the final drive by a 90mmT30E16HVAPshot.

The two Panzer IVs destroyed in the action at Elsdorf are shown below. Both were knocked out with single rounds of T33ammunition, but considerable damage was done to the running gear and external stowage by high explosive.

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By this time action had started to pop on allsides. As related earlier, Sergeant Key's tank (serialnumber 22) was disabled on March 1st by two roundsof high explosive. They caused extensive damage tothe turret and running gear. The blast from the firstshell destroyed the stowage boxes, sand shields, andmany of the end connectors, on the new T80E1double pin tracks. This was one of the first tanksequipped with the new track. The right rear roadwheels were damaged and the sprocket hub split.When the second shell blew off the commander's cu-pola, it also destroyed the fire control instruments,the intercommunication system, and damaged theturret race. Several weeks were required to restore thetank to combat readiness.

The Ordnance team also had its hands full with anumber of non-combat casualties. Two tanks sufferedmain engine failures. The first was serial number 27from Lieutenant Grimball's platoon followed bynumber 37 assigned to Company I of the 33rd Ar-mored Regiment. Both vehicles were repaired andrecommitted to action on March 5th. Another Per-shing threw a connecting rod through the crankcaseof its auxiliary engine and still another was hanginghalf on and half off a bridge over the Erft Canal. Allof these were recovered and repaired.

On March 6th Captain Gray was with the 3rdArmored in Cologne searching for a T26E3 that wasreported knocked out, but was unable to find it dueto bitter fighting taking place in the area. The follow-ing day Cologne was captured and he finally locatedthe tank at the little suburb town of Niehl, north ofCologne on the banks of the Rhine. This was Pershingnumber 25 belonging to Company H of the 33rdArmored Regiment and it had been knocked out by aself-propelled 8.8 cm gun (Nashorn) at under 300yards range. The projectile penetrated the lower frontarmor, passed between the driver's legs and set theturret on fire. The crew successfully abandoned thevehicle before the ammunition blew up gutting theturret. Although the tank was repairable, it wouldhave taken several months to make it combat service-able. Considering the severe shortage of spare parts, itwas evacuated to the rear for cannibalization. Out ofthe original 20 tanks of the Zebra Mission, this wasthe only one which did not finish the war on activeservice.

Sergeant Key's tank, Pershing number 22, is shown in thisphoto sequence. The new type T80E1 double pin track isclearly revealed in the two middle pictures. The lower photo-graph shows the damaged end connectors and drive sprocket.All of this damage resulted from the first hit.

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The second hit on number 22 caused extensive damage insideand outside the turret in addition to blowing off the visioncupola. Looking into the turret at the right above, the azimuthindicator and other fire control equipment is seen to bedamaged from the blast.

Engine replacement and repairs were carried out under field conditions with crude improvised equipment. Despite this, aremarkable record was attained in keeping the tanks serviceable.

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Pershing number 25 knocked out by a self-propelled 8.8 cmgun near Cologne. The hole through the lower front armor onthe driver's side can be seen at the bottom of the photo at theright, a closeup of the same shot hole is shown at the rightbelow. The turret was completely burned out, but the remain-der of the vehicle was undamaged.

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Above: Captain Elmer Gray, at right, and Bill Shaw, the Gen-eral Motors representative, with the 3rd Armored Division inCologne.Below: The Panther destroyed by Pershing number 26 stillburning in front of the Cologne Cathedral.

In the fighting for Cologne on March 6th, Per-shing number 26 commanded by Sergeant Early ofCompany E, 32nd Armored Regiment, knocked outand burned a Panther in front of the CologneCathedral. One round of T33 ammunition struck thebase of the turret just to the left of the gun tube.Another projectile went through the right sponsonand a third penetrated the right front side of the hull.During this same drive T26E3 number 36, from Com-pany D, 32nd Armored Regiment, knocked out aTiger I using two rounds of T33 ammunition. Fromthe same regiment, Company G's Pershing (serialnumber 33) killed a Panzer IV at Manheim with threerounds of M82 through the side.

Some of the most dangerous resistance aroundCologne and other approaches to the Rhine camefrom the heavy antiaircraft defences. These weaponswere deadly when used as antitank guns and the Per-shing's 90 mm high explosive shells proved highlyeffective in dealing with them. The Germans alsoimprovised fixed antitank mounts using the gunsfrom many of their fighting vehicles immobilized bythe fuel shortage.

Captains Gray and Griffin were at Remagen onMarch 12th observing the preparations for ferryingLieutenant Grimball's Pershings across the Rhine.Groups of five bridge pontons were lashed together toform barges and a floor installed. The tanks were thendriven on and pushed across the river using large out-board motors. Griffin and Gray crossed the Rhine onthe 13th and confirmed that the vehicles were ingood condition. A week later Captain Gray was in-formed that additional shipments of T36E3 tankswere expected, so he and his group returned to Paris.

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Above: The Tiger I which knocked out "Fireball" (Pershing number 38), immobilized on a pile of debris and abandoned nearElsdorf.

Below: Pershing from C Company, 19th Tank Battalion, 9th Armored Division moves along the road between Thum andGinnick, Germany, March 1st, 1945. Note the mine exploder in the background.

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The 8.8 cm Pak 43 from a Jagdpanther emplaced as a fixedantitank gun. The weapon was mounted on a concrete basewith 360 degree traverse. The numbers used in the "clock"system of fire control can be seen around the edge of the gunpit. This gun was destroyed by high explosive shells fromPershings of the 9th Armored Division. The covered ammuni-tion storage for the 8.8 cm rounds is shown below.

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A few days before the return to Paris, the firstso-called "Super Pershing" arrived from the UnitedStates. It was the result of an effort to improve thePershing's firepower by installing the new T15E1 90mm gun in T26E1 , number 1. This weapon had amuch higher muzzle velocity than the standard 90mm gun M3 and was comparable in performance tothe German 8.8 cm KwK 43 mounted in the KingTiger. With its new armament, the tank was re-designated as the T26E4, temporary pilot number 1,but retained its old registration number, 30103292.This vehicle is described in more detail later in theDevelopment History.

After proof firing at Aberdeen, the tank wasshipped to Europe and delivered to the 3rd ArmoredDivision's maintenance battalion on March 15, 1945.Before leaving Aberdeen, Slim Price had installed aspecial telescopic sight designed for use with the highvelocity weapon. On arrival, however, the new tele-scope was missing and in its place was the standardM71C sight normally used with the 90 mm gun M3.Captain Gray checked back through all of the unitshandling the tank since its arrival in Europe in aneffort to find the missing sight. He finally flew toParis and located a Lieutenant McDougal who hadbeen in charge of the tank before it was shipped tothe 3rd Armored. McDougal informed him that theM71C scope was installed when the vehicle was re-ceived from the United States. Obviously, an over-zealous depot crew had installed a new M71C sight

when preparing the tank for shipment. Since itproved impossible to obtain a new special sight, Pricehad to work out a range data sheet for use with thestandard scope.

About a week earlier, Gray had rescued thespecial ammunition for the T15E1 gun. These fixedrounds, approximately 50 inches long, had been mis-takenly shipped to the 635th Tank DestroyerBattalion. The 635th was evaluating the new 90 mmT8 antitank gun on the towed carriage T5E2. Thiswas another new weapon brought over by the ZebraMission and it used the same standard ammunition asthe M3 gun. The misplaced rounds came to Gray'sattention when the 635th telephoned to ask why theammunition was 12V2 inches too long for their gun.

In the meantime the maintenance battalion,with Price's help, had been preparing the tank forcombat. Since it had such a powerful gun, they de-cided to improve the armor protection to put it onmore equal terms with the King Tiger. A piece ofarmor was flame cut from the 80 mm glacis plate of acaptured Panther and welded to the front of the gunshield. The front hull armor was reinforced with adouble layer of plate greatly increasing its slope.Some additional stowage boxes were installed and the"Super Pershing" was ready to go about a week afterit was received. With a crew assigned from the 3rdArmored, the tank was moved forward in the hope ofslugging it out with a King Tiger, but the war endedbefore such an encounter occurred.

The "Super Pershing" as fitted up by the 3rd Armored Division maintenance battalion. The two cylinders over the gun mountcontain the coil springs necessary to compensate for the weight of the long heavy gun barrel.

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Details of the armor plate added to the "Super Pershing" areshown in these photographs taken during the modification.The 80 mm plate taken from a Panther can be seen abovewelded to the gun shield. The other views show the doubleplate added to the front hull. Note the additional reinforce-ment above the bow machine gun mount. The effect of theadditional weight added to the front of the tank can be notedabove and in the photograph on the previous page. The extraarmor plus the longer heavier gun barrel badly overloaded thefront torsion bar springs causing the tank to tilt forward.

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The end of the line for the "Super Pershing". The photographson this and the following page show the final resting place ofthe tank in a vehicle dump near Kassel, Germany. These pic-tures were taken by Colonel G. B. Jarrett in June 1945.

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Note that additional armor plate has been attached to eachside of the gun shield since the tank was originally modified.These wing like shields were intended to increase the protec-tion of the upper front sides of the turret. Extra armor wasalso added over the equilibrator spring cylinders. The doubledoor revolving loader's hatch, characteristic of the T26E1, isclearly visible.

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Zebra Mission, Area of Operations

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Early production Medium Tank M26 (T26E3)

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March 25th found the team split up betweenAntwerp and Le Havre to supervise the unloading andtransporting of a new shipment of tanks to their al-lotted destinations. Shortly afterward, Bill Shaw be-came extremely ill at Le Havre and was rushed to ahospital in Paris. Captain Gray, complying with doc-tor's orders, had him flown back to the United States.

The Ninth Army was allocated the first group of40 Pershings (24 from Antwerp plus 16 from LeHavre) from the new shipment. They were dividedwith 22 tanks going to the 2nd Armored Division and18 to the 5th Armored Division. Captain Griffin andSlim Price were sent ahead to the 2nd Armored Divi-sion to arrange training for the tank crews. CaptainGray spent several days setting up the distribution ofspare parts and trying to expedite the modificationsof additional M25 tank transporters. He visited NinthArmy Headquarters on April 2nd and picked up infor-mation on the approximate location of the 2nd Ar-mored Division. Reaching the division after a wildride through 175 miles of very loosely held territory,Gray rejoined Griffin and Price. Very little time hadbeen available for the latter to train the tank crews.After Price boresighted the guns, 45 minutes wereallotted for briefing the men. They then went intoaction without firing a single practice shot.

The Pershings for the 5th Armored Divisionwere now arriving at München Gladbach, so the teamreturned there to set up their school. Classes wereheld for the division maintenance battalion as well asthe members of the 536th Heavy Maintenance TankCompany who were processing the tanks.

Unloading the second shipment of Pershings at Antwerp inMarch 1945. The modem facilities available for spare partsstorage and 'distribution are shown below.

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Pershing convoy enroute to the 2nd Armored Division approaches the Rhine near Wesel, Germany on March 30, 1945. Below,the tanks are crossing the Rhine and refueling on the far side. The Technician 4th Grade in the right photograph wears theinsignia of the 2nd Armored Division.

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T26E4, Temporary Pilot No. 1

The "Super Pershing" after fitting with extra armor in the European Theater

Scale 1:48

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Early production Medium Tank M26 (T26E3)

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Pershings for Patton, tanks assigned to the 11 th Armored Division arrive at Third Army near Frankfurt am Main. Chalk markson the front armor indicate the oil was changed on April 14, 1945.

Thirty T26E3s from the new shipment wereallocated to the l l th Armored Division in Patton'sThird Army. Gray and Price left for Third ArmyHeadquarters on April 4th to make the usual arrange-ments to receive and issue the tanks. Captain Griffinmoved forward with the 5th Armored tanks to brieftheir crews. When Gray and Price checked in at ThirdArmy Headquarters in Frankfurt, they discoveredthat the tanks had not yet arrived. Phone calls toParis to speed up the shipment revealed that theCorps of Engineers could not decide on a suitablebridge to cross the Rhine. After considerable "buckpassing", permission was obtained to use a bridge inthe Seventh Army area. However, by this time theevacuation company handling the movement had al-ready found the bridge and crossed with 15 tanks on

April 12. Permission to use the bridge came throughthe following day.

Classes were set up for the 11 th Armored tankcrews as well as for members of the maintenancebattalion and several Ordnance companies. Threehundred rounds of ammunition were drawn and thecrews were allowed to fire ten rounds per tank. Itproved impossible to locate a suitable 1000 yardrange in the area, so Price had to settle for firingacross a small lake for a distance of 625 yards. Thiswas where he demonstrated his markmanship withthe 90 using the German helmets as targets.

The crews from the l l th Armored completedtheir training and were committed to battle on April21. By this time, additional Ordnance teams hadarrived from the U.S.A. and further training wasturned over to them. The original team returned toParis and then to the United States, arriving in NewYork on April 26, 1945. The flow of Pershings toEurope continued until by VE Day there were 310 inthe Theater of which 200 had been issued to thetroops.

Captain Gray on the autobahn with his team enroute toFrankfurt.

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Demonstration firing for the Third Army across a small lakenear Frankfurt. The smoke produced by firing the 90 mm gunis apparent in these photographs. The effect of 90 mm highexplosive shells in the target area is shown at the right below.

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Medium Tank M45 (T26E2)

Medium Tank M26A1

Scale 1:48

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The problem: A Sherman tank destroyed by the Japanese at Okinawa. This tank had its turret blown off by a satchel chargeafter being knocked out and abandoned.

PERSHINGS TO OKINAWA

The war in Europe was drawing to a close andgreater attention could be given to the situation inthe Pacific. Fierce fighting was in progress onOkinawa with U.S. tank losses far exceeding expecta-tions. In particular, the Japanese were using theirsmall high velocity 47 mm antitank guns with deadlyeffect. The small size of the weapon made it easy toconceal and its armor piercing projectile could pene-trate any part of a Sherman except the glacis plate.At Kakazu, on the morning of April 19th, CompanyA of the 193rd Tank Battalion lost four Shermans toa single 47 mm gun. By the end of May, tank lossesfor the four Army tank battalions reached 221, ofwhich 94 were damaged beyond repair. In the face ofthis heavy opposition, the tankers were demandinggreater firepower and more armor protection. As aninterim measure, the Ordnance maintenance com-panies were welding track links and extra sections ofarmor to the sides of the Shermans. However, thebest answer appeared to be the Pershing, now stan-dardized as the M26.

A closeup view of the Sherman shows the extra armor plateadded to the sides in an effort to gain protection from the 47mm Japanese antitank gun.

Less than three weeks after his return, CaptainGray was called to a meeting in the office of BrigadierGeneral Borden, Chief of the New DevelopmentsDivision, Washington, D.C. He was advised that a mis-sion was being formed for the immediate shipment of12 Pershing tanks with tools and ammunition toNaha, Okinawa.

Because of his previous experience introducingthe tank in Germany, Gray was asked to head themission and institute a training program in the useand care of the vehicle for both the operating person-nel and Ordnance maintenance crews. Changes ormodifications necessary for use in the Pacific Theater

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were also to be noted. Returning to Detroit on May16th, Gray was joined by Captain William Tauss,Engineer and Project Officer for the M26 tanks, whowas also assigned to the mission. With preparationscomplete, the two captains departed for Seattle,arriving on May 24th. Having learned from earliermissions to take nothing for granted, they began tocheck the various shipments which were to. accom-pany the tanks to their destination. This check re-vealed that many parts and major replacement unitswere back ordered. Previous experience had shownthat it was highly unlikely that any such backordered items would arrive in time to be of use to themission. Fortunately, a quick search discovered twoM26s at the Richmond Tank Depot and a telegram toWashington obtained permission to cannibalize thesevehicles. Two complete power trains, one auxiliaryengine and generator set, and one radiator assemblywere removed and trucked to Mukiltea, Washington,where the ship was being loaded with ammunition.

The ship, the S.S. Katherine D. Sherwood, sailedon May 31st and since their orders read, "Direct ship-ment", they happily believed they would be in Okina-wa not later than June 30th. Unfortunately, they didnot reckon with the strained communications in thePacific Theater. This became apparent at the first stopat Eniwetok. Expecting a one or two day delay, theywere informed that the ship would leave in ten tofifteen days and the destination would then be Ulithi.

M26 tanks being lifted from the hold of the S.S. Katherine D. Sherwood off Naha, Okinawa. Lack of docking facilitiesrequired that the tanks be transferred to landing craft in the open sea.

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Pershings being lowered into the Mark VI LCTs off Naha. Thetanks were fueled and the engines started to enable them tomaneuver under their own power.

When Gray tried to explain their mission to the portdirector and inform him that the tanks were beingshipped on a high priority basis to alleviate the situa-tion on Okinawa, he replied that since the ship had alow priority there was not much he could do. A radiomessage was sent to General Barnes' office and a let-ter to Colonel Colby explaining the situation.

After sweating it out for ten days, the shiphoisted anchor on June 27th and headed for Ulithi,1350 miles away. It was the same story all over again,with an expected delay of ten days to two weeks.They were further informed that ships were sent toOkinawa only as they were called forward by namefrom that area. A few days were spent trying to getthe ship routed to Okinawa and the two captains sentan informative letter through channels to GeneralStillwell. After 12 days at Ulithi they left in convoyon July 15th and arriving Okinawa on July 21. Bythis time all action had ceased and the build up wasstarting in preparation for the invasion of Japan.

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The first two Pershings ashore at Naha on July 31, 1945.

Unlike Europe, the unloading facilities at Okina-wa were extremely crude, requiring the tanks to beloaded into LCTs and landed on the open beach. Fur-ther delays occurred when it was discovered that onlythe later mark LCTs could handle the large Pershings.Finally, late on July 30th, the first two tanks weretransferred to the LCTs and landed on the beach atNaha the following day. Two more tanks were movedashore before all operations were stopped by typhoonwarnings from the local weather station. The remain-ing vehicles were lashed down and the ship put out tosea to ride out the storm. They returned to Naha onAugust 4th and the remaining eight tanks were un-loaded.

Arrangements were made to train personnelfrom the 193rd and 711th Tank Battalions with sixPershings to go to each unit. The 81st and the 293rd

Heavy Maintenance Tank Companies were to be in-cluded in the training program.

On August 10th, the first class was conductedby Gray, now promoted to Major, at the 193rd TankBattalion. That night, word was received that Japanmight accept the terms laid down at the PotsdamConference and orders were issued to discontinue alltraining and stand by. Tenth Army had instructionsto be ready for overseas movement to Korea in 17days. V-J Day on August 15th closed the chapter.Since the tanks would no longer be used in combat,the mission was considered completed and Gray andTauss were free to return to the U.S.A. They leftOkinawa August 21, arriving at San Pedro, California,Sept. 14, 1945. The war was finished and, except fora period in Korea, so was the combat history of thePershing tank.

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One of the first four Pershings landed at Okinawa on July 31, 1945.

Display of the Pershing with other new equipment on Okinawa. The officer in the righthand photograph is Captain WilliamTauss, Project Officer for the M26.

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Although poor in quality, the two photographs here are included because of their rarity. To the author's knowledge, they arethe only photographs available of the Pershing test firing at Okinawa.

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MISSION TO OKINAWASerial and Registration Numbers of 12 M26 Tanks

Serial Registration Serial RegistrationNo. No. No. No.

586 30127332 617 30127363603 30127349 621 30127367606 30127352 623 30127369608 30127354 625 30127371609 30127355 629 30127375614 30127360 632 30127378

All of these tanks were manufactured by the Fisher Body Division ofGeneral Motors Corporation.

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PART II

THE DEVELOPMENT HISTORY

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At the left is an early artist's conception of the T20 design. Note the resemblance to the gun shield of the 3 inch gun motorcarriage MIO on which the T80 gun mount was based. The mock-up of the T20 as presented in May 1942 is shown at rightwith the T79 gun mount.

REQUIREMENT FOR A NEW TANK

The development program which finally evolvedthe Pershing began in the spring of 1942. WhenColonel Joseph Colby returned from Africa in April,the medium tank M4 (General Sherman) was justcoming into full production. At that time it was con-sidered superior to any tank on the African battle-field. However, German tank development showed atrend toward greater firepower and improved armorprotection. This was illustrated by appearance of thePanzer III J with strengthened front armor and a long5 cm L/60 cannon. Nineteen of these tanks were onstrength with the Afrika Korps for the battle ofGazala in late May 1942. Shortly thereafter, the first

Panzer IV F2 vehicles were received mounting thelong 7.5 cm KwK 40, a much more powerful weaponthan the Sherman's 75.

The time was then considered ripe for planning asuccessor to the Sherman. Such a successor requiredimprovements in firepower, mobility, and armorprotection if it was to maintain an advantage overexpected German developments. It was intended thatthe new series of tanks would take advantage of thelessons learned in battle as well as the technical ad-vances that had occurred since the design of the Sher-man. General Barnes and Colonel Colby proposedwhat was then considered a rather radical design to

An artist's conception of an early stage in the design study fora new tank. The sponsons are retained and the turret bears astrong resemblance to the Sherman. Note the sloped sidearmor.

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meet these objectives. The new tank retained thesame general layout as the Sherman with a five mancrew. The driver and assistant driver were seated inthe front hull while the tank commander, gunner, andloader rode in the turret. To achieve the maximumarmor protection with a minimum of weight, a newtechnique of "Space Engineering" was used to designthe hull. Using this concept, the hull was simplified toa box like structure eliminating the sponsons foundon the M4. The simple shape reduced the surfacearea, allowing a given volume to be enclosed withthicker armor than the earlier more complex design,while maintaining the same total weight. The volumeto be enclosed was also minimized by removing allnonessential equipment from inside the hull. Many ofthese items, carried inside the Sherman, were placedin external stowage boxes over the tracks. The hullwas designed to fit the new low silhouette Ford V-8,Model GAN, tank engine, greatly reducing the overallvehicle height. The GAN engine was essentially theModel GAA used to power the medium tank M4A3,modified to fit in a low silhouette vehicle. At a laterdate, other minor modifications changed the designa-tion to GAP. Addition of an automatic transmissionalso promised improvements in ease of handling andmobility.

The hull and fighting compartments were ven-tilated by a rotoclone blower mounted on the hullroof between the driver and assistant driver. Theblower was intended to maintain a slight positivepressure within the vehicle when buttoned up andexpel the powder gases when the guns were firing.The housing and intake for the blower formed a largebulge at the top center of the front armor plate givinga characteristic appearance to all tanks of the T20series.

The proposed main armament was the new 76mm gun Tl , a light weight weapon developed to in-crease the firepower of medium tanks then equippedwith the 75 mm gun M3. Although designated as a76, the bore was actually 76.2 mm, or 3 inches indiameter and 57 calibers in length. After test, it wasshortened to 52 calibers and standardized as the 76mm gun Ml . Further testing produced the M1A1with changes in the external tube contour. The recoilsurface was also lengthened by 12 inches permittingthe trunnions to be mounted closer to the center ofgravity giving better balance to the long gun. The newweapon was originally intended to fit into the Sher-man turret using the same mount, but tests showedthis arrangement to be overcrowded. To avoid alengthy ammunition development program, the new76 was designed to use the standard projectiles forthe 3 inch gun already in service. These projectileswere fitted to a smaller cartridge case, but the powdercharge was adjusted to obtain the same muzzle velo-city as the 3 inch piece. With armor piercing ammu-nition, the muzzle velocity was 2600 ft/sec compared

to 2030 ft/sec for the Sherman's 75 mm M3 tankgun. The higher velocity increased the armor pene-tration by approximately one inch and was slightlysuperior to the German 7.5 cm KwK 40 in the PanzerIV F2. With a light weight tube and breech ring, the76 was approximately two thirds the weight of the 3inch tank gun M7.

In May 1942, a mock-up of the proposed tankwas constructed by the Product Study Division ofGeneral Motors Corporation. The design offered amedium tank with Vz inch more armor, a 76 mm highvelocity gun, and an automatic transmission forapproximately the equivalent weight of the M4.Generals Devers and Somervell, as well as other highranking officers, viewed the mock-up and gave theirenthusiastic approval. Ordnance Committee actiondesignated the new vehicle as the medium tank T20and approved the construction of two pilot tanks.

Since the 76 mm gun was just being developed,alternate armament combinations were considered.These included the 3 inch gun M7 as mounted in theM6 heavy tank and the M I O tank destroyer, and a 75mm M3 gun with an automatic loader. It was alsodesired to investigate the best possible combinationof transmission and suspension systems. For this pur-pose four additional pilot vehicles were authorized inSeptember, 1942. Two of these, designated mediumtank T22, were to be equipped with a rearranged ver-sion of the Sherman's gear box transmission and wereto be built at Chrysler Corporation. The other twovehicles were designated medium tanks T23 and usedthe electric drive developed at the General ElectricCompany for the T1E1 heavy tank. The followingnumbers were assigned for the various combinationsof armament.

Medium tanks T20, T22, and T23 were to beequipped with the 76 mm gun Ml. Medium tanksT20E1, T22E1, and T23E1 were to be fitted with the75 mm gun M3 in a special turret with an automaticloader. The T20E2, T22E2, and T23E2 designationswere reserved for vehicles armed with the 3 inch gunM7.

By the time the first pilots were constructed, the76 mm gun had proved successful. Since the 3 inchgun was heavier in weight and identical in perfor-mance to the 76, no models of the T20E2, T22E2 orT23E2 were ever constructed. Only one turret wascompleted with the 75 mm gun M3 using the auto-matic loader. This was fitted to medium tank T22,pilot number 1 and the vehicle was redesignatedmedium tank T22E1. No T20E1 or T23E1 vehicleswere built. The second pilot T20 was fitted with atorsion bar suspension and designated T20E3. As thedevelopment program progressed, additional numberswere assigned to cover various modifications ofrunning gear, power trains, armament, and armor pro-tection. These are discussed in detail in following sec-tions.

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Development Chronology of the T20 Series, 1942-1945

* Standardization proposed asH27 (T23E3) and M27B1 (T20E3)

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The T20 pilot after completion at the Fisher Body Division of General Motors in May 1943. The lugs on the right side of theturret were for mounting an early version of the hoisting device used for removing the power train.

THE T20 AND T20E3

In May 1942 the contract for the T20 pilottanks was given to the Fisher Body Division ofGeneral Motors Corporation and the first T20 pilotwas completed a year later in late May 1943. Thevehicle reflected the design changes resulting from theJanuary conference between Ordnance and theArmored Force. These changes improved the sittingheight for the drivers and enlarged their entrancehatches. The new front end was a welded assembly ofcastings and rolled plate. The same conference alsoconcluded that the tanks would be approximately 2l/2tons heavier than the original design weight and thatnumerous improvements were necessary, particularlyin the ammunition stowage. The quantity of ammuni-tion carried was considered below the minimum re-quired and insufficient protection was provided forthe rounds stowed in the turret. This criticism alsoapplied to the other T20 series pilots under con-struction at that time. However, it was agreed thatthe pilots would be completed for comparison testpurposes.

T20 number 1 was equipped with an early typeof horizontal volute spring suspension using the same16 9/16 inch wide double pin, rubber block track asthe medium tank M4. Two wheel bogies weremounted, three on each side of the vehicle, with

hydraulic direct acting shock absorbers controllingthe movement of the front and rear suspension units.M4 type track support rollers were attached directlyto the hull at the rear of each bogie and track tensioncould be adjusted by moving the idlers fitted at thefront corners of the hull. The tracks were driven bysprockets attached to the final drives mounted oneach side at the rear. Power from the Ford tankengine passed through the new type torqmatic trans-mission to the differential and then to the finaldrives. The torqmatic transmission was the Model30-3OB, consisting of an hydraulic torque converterin series with planetary gearing allowing three speedsforward and one reverse. The complete power trainconsisting of engine, transmission and differential wasremovable as a unit.

The registration number for the first pilot was30103302. After completion, the tank was sent tothe General Motors Proving Ground for tests and thenreturned to the manufacturer for correction of de-fects. The torqmatic transmission proved to be a con-stant source of trouble. The major defects were oilleaks and overheating. The T20 was shipped to Aber-deen Proving Ground in February 1944. However,more promising developments were now available andno further tests were conducted.

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The early type horizontal volute spring suspension can be seenon these views of the T20 pilot. Close examination of the sideview will show the shock absorbers mounted on the front andrear bogies. The front view shows the weld joints between theupper hull casting and the rolled front plate. The joints arealso visible around the ball mount casting and the adjustableidler mounts at each front corner.

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The T20 pilot is shown above with the gun forward (top left)and locked in the travel position (top right). The circular rotat-ing hatch for the tank commander is the same as on the M4medium tank with a mount for an antiaircraft machine gunand a periscope in one side of the split cover. This early ver-sion of the loader's hatch with the rectangular split cover isoriented parallel to the axis of the gun tube. The loader'speriscope cover is just forward of the hatch. The tank is shownwith all covers open at the left. The vertical mounted coolingfans can be seen at the rear of the engine compartment.

The T20 pilot under test at General Motors Proving Ground in June 1943. The gun is locked in the travel position in bothviews. Note the absence of a pistol port in this turret.

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Scale 1:48Medium Tank T20, Pilot

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The breech of the 76 mm gun can be seen at the bottom of the picture at the left above. The weapon is mounted so thebreechblock slides in the horizontal direction. The empty bracket for the coaxial .30 caliber machine gun can be seen just tothe left of the 76. The hole for the gunner's telescopic sight appears to the right of the gun mount. At the right above is aview looking into the turret through the tank commander's hatch. The upper and lower seats for the tank commander are inthe folded position. The recoil guard for the 76 mm gun appears at the left side of the opening.

The driver's and assistant driver's positions are shown below at the left and right respectively. The instrument panel can bepartially seen mounted between the two drivers and the empty bow machine gun mount appears at the right. The bolt headsin the side walls are for mounting the forward suspension bogies.

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The engine compartment is shown (top left) with the powerunit removed. Fuel tanks are located in the forward end withthe auxiliary engine and generator installed along the left wall.Control rods extend along the bottom of the compartment.The power unit is installed (top right) and the radiators can beseen behind the vertical cooling fans. The location of the var-ious power unit components is diagramed at the left.

The power unit removed from the tank appears in these photographs. A closeup (at left) shows the rear of the unit and thecontrolled differential. With this arrangement the cooling fans were removed with the power unit. The linkage required todrive these fans can be seen in the photograph at the right.

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The Armored Force, in September 1942 recom-mended that one of the T20 pilots be completed witha torsion bar suspension and wider tracks in an effortto improve the ride and reduce the ground pressure.To avoid confusion, the second pilot was redesignatedT20E3 by Ordnance Committee action in February1943. The pilot T20E3, with registration number30104303, was completed on July 1, 1943. Thisvehicle was equipped with a torsion bar suspensionwhich was a modified version of that just going intoproduction on the 76 mm gun motor carriage M18.As fitted to the T20E3, the suspension consisted ofsix dual disc road wheels on each side of the vehicle.These wheels were mounted on support arms at-tached to the ends of torsion bars fitted transverselyacross the bottom of the tank. This arrangementallowed a wheel movement up to about eight inchesand shock absorbers were applied to the first two andthe last two wheels on each side. The idler wheel wasconnected to the front road wheel to compensate forslack in the track. As originally constructed, threepairs of dual track support rollers were fitted. Later,an additional two pairs were added, giving five dualtrack support rollers on each side of the vehicle. An 18inch wide single pin, cast steel, center guided trackwas driven through extensions of the track pins.

Although completed on July 1, 1943, theT20E3 was retained temporarily by the manufacturerfor the correction of defects. As a result of a fire, alarge part of the vehicle had to be rebuilt, using someparts from the T20 pilot. The tank was then shippedto Aberdeen Proving Ground for comparative ride

tests with M4 medium tanks equipped with the ver-tical volute spring suspension. These tests indicated aconsiderable ride improvement over the vertical vo-lute spring suspension, but showed the need forstrengthening the shock absorbers and their mount-ings. Transmission difficulties similar to those en-countered with the T20 pilot precluded extensivetests and the Ordnance Committee recommendedthat the project be cancelled in December 1944.

A design study in April 1943 showed the T20equipped with the original version of the General Mo-tors cross-drive transmission. An extremely compactunit, the new transmission was actually tested in amodified M4A3. After further development, thecross-drive was applied to the M26E2 and then to theM46 during the postwar period.

The turrets of both the T20 and T20E3 werearmed with the 76 mm gun and a .30 cal machine gunin the coaxial combination gun mount T79. This wasa modified version of the Sherman's 75 mm gunmount M34. Both vehicles were equipped with essen-tially identical cast turrets reflecting the stage of tur-ret development at the time of their construction.The tank commander was provided with a revolvingring type hatch with a fitting for a .50 cal antiaircraftmachine gun. The loader's hatch was smaller,rectangular in shape, with double doors. The turretswere obviously produced during the period whenpistol ports were out of favor as neither was fittedwith one. The discussion of turret and gun mountdevelopment in the section on the T23 appliesequally to other models of the T20 series.

Pilot T20E3 after completion at Fisher in July 1943. Note there are only three track return rollers per side.

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The single pin, center guided tracks and torsion bar suspensionshow a strong resemblance to those on the 76 mm gun motorcarriage Ml 8 from which they were developed. A 27 toothsprocket replaced the familiar 13 tooth sprocket found on theT20. The shock absorbers on the first two and last two roadwheels are visible in the upper and lower photographs. The guntraveling lock of the T20 has been replaced with a single restfor the gun tube and a new more rounded casting design hasbeen applied to the bow machine gun mount.

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Later photographs of the T20E3 at Aberdeen Proving Groundshow the modified suspension with five track return rollers.The .30 and .50 caliber machine guns have also been installed.

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T22 pilot number 1 after completion at Chrysler in June 1943. The shock absorbers on the front and rear bogies of the earlyhorizontal volute spring suspension are easily seen in this photograph.

THET22 AND T22E1

The two pilot medium tanks T22 were con-structed by Chrysler Corporation and completed inJune 1943. Their registration numbers were pilotnumber 1, 30104304 and pilot number 2, 30104305.These tanks followed the same basic design as themedium tank T20. However, they were fitted withthe power train components of the medium tankM4A3, but these components were modified and rear-ranged. For example, the transmission and differ-ential, although similar to those used in the M4 seriesvehicles, were mounted in different type cases andthe assembly operated as a dry sump, with no gearsdipping in oil. The gear box transmission and con-trolled differential were fitted behind the engine inthe hull. The transmission and differential had thesame gear ratios as the M4A3 with five speeds for-ward and one reverse. As with the T20, the finaldrives were mounted on the outside of the hull at therear of the tank. The early horizontal volute springsuspension with direct acting shock absorbers on thefront and rear bogies was applied to the T22s as well

as the T20. This type of suspension gave someimprovement in ride over the Sherman's vertical vo-lute spring system. However, in this early form withthe same narrow 16-9/16 inch track, the improve-ment was insufficient to warrant slowing productionof the Sherman to make a change.

Other modifications were made based on the ex-perience with the T20 pilot. To permit the circulationof cool air around the auxiliary generator, it wasshifted forward about eighteen inches and the oilcoolers were moved to the right side of the enginecompartment. The batteries were transferred fromthe engine compartment to a position between thedriver and assistant driver.

During tests at the Tank Arsenal ProvingGround, engine trouble was encountered in the firstpilot after driving 900 miles. At this point, a con-necting rod went completely through the crankcasewall requiring replacement of the engine. The secondpilot vehicle was sent to Aberdeen Proving Groundwhere considerable engine and transmission difficul-ties occurred requiring the installation of a newpower train. Because of these problems, furtherdevelopment work was discontinued and in February1944 the tests were suspended because of higherpriority work.

The left rear view with the gun in the traveling position showsthe gun rest similar to that on the T20E3. T48, double pin,rubber chevron tracks are fitted to this tank.

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Other views of T22 pilot number 1 are shown above and below. The turret and gun mount were quite similar to the T20 andT20E3, but the bow machine gun mount casting more closely resembles that of the T20. Note the pistol port has beenwelded over.

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The T22 pilot number 2 under test at Aberdeen ProvingGround. Note that the welding of the upper front armor plateon both T22 pilots differs from the T20 and T20E3. Theperiscope in the commander's hatch cover is centrallymounted, unlike other hatches of this type. The periscopemount is fitted to one side of the split hatch cover extendinginto the simicircular opening on the other side when the hatchis closed. Compare with the top views of T22 number 1 andthe T20.

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Scale 1:48

Medium Tank T22, Pilot Number 1

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The drivers' compartment during assembly (above) shows thecontrol linkage. The driver's seat is mounted, but the assistantdriver's seat and escape hatch cover is still missing. The roto-clone blower appears at the upper center of the photograph.

The two photographs at the left are taken through the turretring opening before installation of the turret. Looking forward(upper), the driver's seat and the fixed fire extinguisher bottlesare visible. Looking toward the rear (lower) reveals the open-ing into the engine compartment with air cleaners on eitherside. Racks for 76 mm ammunition stowage are located onboth sides of the hull.

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The view above is looking toward the rear over the engine compartment prior to installation of the covers or the turret. Thecontrols just below the turret ring are for the auxiliary engine and generator.

Two views above show the engine compartment with the power train removed. The fuel tanks appear on each side of theopening into the fighting compartment. The small conical jets are fire extinguisher outlets. The two views below are of thepower unit with the fans removed.

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Above and below are two views of the T22E1 pilot after conversion from T22 pilot number 1.

Both pilots initially carried the same type of castturret and T79 gun mount as the T20. By this time,this turret design was considered obsolete and the 76mm gun tubes installed in the pilots were unsafe foruse. To prevent any firing, the tubes were pluggedwith wooden blocks. T22 pilot number 1 was laterfitted with the special turret mounting the 75 mmgun M3 equipped with an automatic loader. This tur-ret , designed and constructed by United ShoeMachinery Corporation, was originally intended forthe medium tank T20E1. When fitted with this tur-ret, the pilot was redesignated medium tank T22E1.The gun and mount had been tested by proof firing inNovember 1942. These tests revealed some high fric-tion in the system and later tests in April 1943 re-vealed difficulty with the automatic spring rammer.After redesign it was fired automatically at a rate of20 rounds per minute. The turret was fitted to theT22 vehicle in August 1943 and proof fired at Salis-bury Beach, New Hampshire. As a result of thesetests, a safety device to stop the loader, when anempty case was not completely ejected, was built intothe mechanism and further firing tests were con-ducted.

The T22E1 turret was similar in size and shapeto the standard 75 mm gun turret used on the me-dium tank M4. It also used the M34 gun mount em-ployed on the M4 series. Since it was fitted with anautomatic loader, the turret crew was reduced to two,the tank commander and the gunner. The tank com-mander was moved to the left of the 75 mm gunbelow a revolving hatch fitted with a .50 caliber ma-chine gun for antiaircraft use. The gunner's position

remained to the right of the 75 mm gun with a smallescape hatch in the turret roof. The turret could bereadily identified by the protrusion in the center rearof the roof necessary to permit clearance for theautomatic loading mechanism. The loader itself wasfed from two 32 round magazines, one on each sideof the gun. Normally this meant 32 rounds of highexplosive in one magazine and 32 rounds of armorpiercing ammunition in the other. The selection ofammunition was made by the tank commander, usingthe control mounted on the left side of the turret.

The T22E1 was shipped to Aberdeen ProvingGround in November 1943 for complete firing tests.These tests indicated that an automatic gun gave su-perior performance to a hand loaded gun, but theequipment did not have sufficient mechanical relia-bility. In addition, the 75 mm gun no longer providedadequate firepower for a medium tank. For thesereasons, the work on the project was suspended inFebruary 1944.

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T22E1 pilot under test at Aberdeen Proving Ground. Acounterweight has been added to the gun muzzle to balancepart of the automatic loading mechanism and improve thestabilizer performance. The bulge at the center rear of theturret roof is an immediate point of recognition. This wasnecessary to permit adequate clearance for the automaticloader.

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Sectional view of turret showing automatic loader

Interior views of the turret show the tank commander's posi-tion (above) and the gunner's station (right).

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Scale 1:48

Medium Tank T22E1, Pilot (converted from T22, Pilot Number 1)

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T23 pilot number 2 in March 1943.

THE T23, T23E3, AND T23E4

Although highest in number, the first of the ori-ginal pilots to be completed was the medium tankT23. Pilot number 1 (registration number 3098787),with the exception of the fighting compartment, wascompleted at the General Electric Company's ErieWorks in January 1943. Construction had beenauthorized after the exceptional performance obtain-able with an electric drive was noted during tests ofthe heavy tank T1E1. The same drive was modifiedfor use with the Ford GAN tank engine in mediumtank T23. With this system, the engine drove an elec-tric generator, the controlled output of whichpowered two individual traction motors operating thefinal drives. Since there was no mechanical connec-tion between the engine and tracks, the engine speedcould be varied and controlled without being in directproportion to the vehicle speed. It was thereforepossible to operate the engine at its most efficientspeed at all times. Such a design held the possibilityfor an appreciable increase in engine life. Preliminarytests showed the tank was extremely maneuverable,could turn in its own length, and had a maximumspeed of 35 miles per hour. Unlike the other T20series pilots, the T23 was fitted with the same verticalvolute spring suspension found on the M4 tanks. Thesprockets were mounted on the final drives at the rearof the hull and track tension was maintained byadjustable fixed idlers at the front of each track. Thesuspension carried the standard 16-9/16 wide T51track.

Pilot number 1 was completed before the deci-sions reached at the January meeting between Ord-nance and the Armored Force were put into effect.

However, the hull for the second pilot was refab-ricated to increase the sitting height and enlarge thedrivers' hatches. The upper front hull of both vehicleswas welded from rolled plate fitted around the roto-clone housing. The large casting including the roto-clone housing and extending across the full width ofthe hull was not introduced in the T23 until the pro-duction pilot was completed in October 1943.

The T23 pilot number 1 also differed from theother pilot vehicles in being fitted with a welded tur-ret. This resulted from the program to develop animproved turret and mount for the 76 mm gun. Theeffort began during the months of July and August1942 when the original 76 mm gun T1 was installedin the combination mount M34 and fitted to amedium tank M4A1. The new installation required acounterweight of approximately 800 pounds tobalance the gun mount. The elevating mechanism wastoo weak and the turret was cramped, preventingefficient operation of the gun and mount. To correctthis, a design study was initiated to develop an im-proved turret for mounting a 76 mm gun on mediumtanks. The 76 had meanwhile been shortened fivecalibers or 15 inches and modified to improve itsbalance. It was around this weapon, the 76 mm gunM1A1, that the design proceeded. The 76 was equip-ped with an elevation stabilizer in all T20 seriesvehicles.

After preliminary studies, it was decided to pro-ceed with the detailed design of two different turretsand mounts. One gun mount design was based on thecombination mount M34, already in use with the 75mm gun in the M4 tanks. The gun cradle was a rotor

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T23 pilot number 2 in March 1943.

THE T23, T23E3, AND T23E4

Although highest in number, the first of the ori-ginal pilots to be completed was the medium tankT23. Pilot number 1 (registration number 3098787),with the exception of the fighting compartment, wascompleted at the General Electric Company's ErieWorks in January 1943. Construction had beenauthorized after the exceptional performance obtain-able with an electric drive was noted during tests ofthe heavy tank T1E1. The same drive was modifiedfor use with the Ford GAN tank engine in mediumtank T23. With this system, the engine drove an elec-tric generator, the controlled output of whichpowered two individual traction motors operating thefinal drives. Since there was no mechanical connec-tion between the engine and tracks, the engine speedcould be varied and controlled without being in directproportion to the vehicle speed. It was thereforepossible to operate the engine at its most efficientspeed at all times. Such a design held the possibilityfor an appreciable increase in engine life. Preliminarytests showed the tank was extremely maneuverable,could turn in its own length, and had a maximumspeed of 35 miles per hour. Unlike the other T20series pilots, the T23 was fitted with the same verticalvolute spring suspension found on the M4 tanks. Thesprockets were mounted on the final drives at the rearof the hull and track tension was maintained byadjustable fixed idlers at the front of each track. Thesuspension carried the standard 16-9/16 wide T51track.

Pilot number 1 was completed before the deci-sions reached at the January meeting between Ord-nance and the Armored Force were put into effect.

However, the hull for the second pilot was refab-ricated to increase the sitting height and enlarge thedrivers' hatches. The upper front hull of both vehicleswas welded from rolled plate fitted around the roto-clone housing. The large casting including the roto-clone housing and extending across the full width ofthe hull was not introduced in the T23 until the pro-duction pilot was completed in October 1943.

The T23 pilot number 1 also differed from theother pilot vehicles in being fitted with a welded tur-ret. This resulted from the program to develop animproved turret and mount for the 76 mm gun. Theeffort began during the months of July and August1942 when the original 76 mm gun T1 was installedin the combination mount M34 and fitted to amedium tank M4A1. The new installation required acounterweight of approximately 800 pounds tobalance the gun mount. The elevating mechanism wastoo weak and the turret was cramped, preventingefficient operation of the gun and mount. To correctthis, a design study was initiated to develop an im-proved turret for mounting a 76 mm gun on mediumtanks. The 76 had meanwhile been shortened fivecalibers or 15 inches and modified to improve itsbalance. It was around this weapon, the 76 mm gunM1A1, that the design proceeded. The 76 was equip-ped with an elevation stabilizer in all T20 seriesvehicles.

After preliminary studies, it was decided to pro-ceed with the detailed design of two different turretsand mounts. One gun mount design was based on thecombination mount M34, already in use with the 75mm gun in the M4 tanks. The gun cradle was a rotor

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T23 pilot number 1 with welded turret and the early T80 gun mount. Note the vertical volute spring suspension as on theSherman.

mounted on bearings in a fixed front plate which wasbolted to the machined surface on the front of theturret. A small rotor shield was fitted around the gunbarrel and bolted to the rotor to protect the ma-chined surface exposed through the opening in thefixed front plate when the gun was elevated or de-pressed. A direct sight telescope was added for thegunner as well as the standard M4 periscope sight. Acoaxial .30 caliber machine gun was mounted to theleft of the main weapon. This version was assignedthe designation, combination gun mount T79 and theturret to which it was assembled was based on thestandard M4 design. The turret was of cast construc-tion and, in addition to the revolving hatch over thecommander's position, provided a smaller hatch withdouble doors for the loader. The commander and

loader were each equipped with an M6 periscope andthe revolving ring on the commander's hatchmounted a .50 caliber antiaircraft machine gun.Photographs taken in March 1943 show this turret onthe second pilot T23 (registration number 3098788)and the same type was installed on the T20, T20E3,and the T22.

In the second type of gun mount, the turretfront plate was eliminated and replaced by a largemoveable shield to which the gun cradle was bolted.This shield was attached to the turret body by meansof trunnion bearings, the trunnion pins which carriedthese bearings being supported by the turret body.The design was assigned the designation, combinationgun mount T80, and the original turret body towhich it was assembled was of all welded construc-tion. This turret was much better balanced than thecast turret used with the T79 mount, since the bustleextended further to the rear.

A single turret basket design was used for bothturrets. Forty-two rounds of 76 mm ammunitionwere carried in this basket as well as sufficient caliber.30 and caliber .50 ammunition for the machine guns.It was the welded turret with early T80 gun mountwhich was fitted to medium tank T23 pilot number1.

T23 pilot number 1 during tests at General Electric to deter-mine the center of gravity.

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After satisfactory results were obtained in tests,the combination gun mount T80 was released forproduction. The welded turret for this mount wasredesigned as a cast turret and the bulge contour atthe rear changed to improve the balance and permitits use on the M4 tank series as well. The change wasnecessary to clear the drivers' hatches on the M4tanks. When mounted on the M4 series, it was alsonecessary to provide a ventilating fan at the rear ofthe turret, since those vehicles were not equippedwith a hull mounted rotoclone blower. This was theturret adopted for the production T23 tanks with theT80 mount standardized as the M62.

Details of the welded turret are revealed in this example pre-pared for ballistic tests. It has the same general arrangement asthe cast turret.Note that the pistol port has been welded shut.A view of the turret roof (below) during tests at General Elec-tric shows details of the hatches and periscope covers. The seatwas obviously mounted for use during test operations.

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Scale 1:48

Medium Tank T23, Pilot Number 1

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T23 pilot number 2 in March 1943 with the cast turret and T79 gun mount. The pistol port has been eliminated on this modeland no traveling lock is fitted for the 76 mm gun.

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Further details of pilot number 2. The power train arrange-ment is shown above. Note also, that a .30 caliber machine gunis mounted on the tank commander's hatch. Later, a .50 cali-ber machine gun was standard for this position. The engineexhaust is the opening between the spare track links in the rearview. Periscopes for the drivers were mounted both in thehatch covers and adjacent to the hatch (below left). This viewalso shows the welded assembly of the front hull armor.

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Scale 1:48Medium Tank T23, Pilot Number 2

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The drivers' compartment during assembly (above) compared with each position below after stowage was complete. At leftbelow, the driver's controls are seen at each arm of his seat. Similar controls are provided for the assistant driver (below right)plus the .30 caliber machine gun in the bow mount. The escape hatches are in the floor directly in front of each seat.

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Turret stowage arrangements in pilot number 2 are shownhere. The loader's position (above) provides ready access tothe 76 mm ammunition stowed around the turret. Note thecounterweight in the recoil guard necessary to balance the 76mm gun. A view through the commander's hatch (top right)shows his upper and lower seats folded. The gunner's seat is atthe top center of the photograph. Looking toward the rear ofthe turret (center right), the radio can be seen mounted in theturret bustle partially obscured by the recoil guard of the 76mm gun. The remaining view (bottom right) is from under-neath the gun and shows the access to the driving compart-ment. The gunner's seat is at the right.

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The production pilot T23 (serial number 3). Note the weldedassembly of castings and rolled plate in the front hull. Thepistol port is still absent from this first production tank, but atraveling lock has been added for the gun.

Details of the new production turret are shown below. Thetank commander has been equipped with a vision cupola andthe rotating hatch moved to the loader's position. Lugs formounting a power train hoisting device are welded to the rightside of the turret.

The preliminary tests on the T23 pilot modelsproved so promising that a production contract for250 tanks was approved in May 1943. The regis-tration numbers were 30103052 through 30103301.However, 30103252 through 30103301 were laterassigned to the T25E1 and T26E1 and the number ofT23s reduced to 200 on this contract. A later con-tract for an additional 50 T23s brought the total backto 250 by the time production ceased in December1944. The production total of 250 also included thetwo T25 pilots originally classified as T23s with the90 mm gun. Their registration numbers were30103053 and 30103054. The first production pilotincorporating several modifications was completed inOctober 1943 and shipped to Aberdeen ProvingGround.

The production T23 carried the improved castturret with a T80 (M62) gun mount and was fittedwith a vision cupola for the tank commander. Therevolving hatch with the antiaircraft machine gun wasmoved to the loader's position and a 2 inch smokemortar M3 was mounted in the left front turret roof.The front armor plate thickness was increased to 3inches instead of the 2J/2 inches on the pilots. Addi-tional improvements based on tests at Fort Knoxwere incorporated during the production run. Thelater production vehicles had complete water proof-ing for all electrical parts and electric brakes for emer-gency stopping, if power was lost. Improved enginecomponents such as valves, gaskets, and spark ad-vance governors were also included as a result of thetesting program.

An interesting feature of the electric drive tankswas their ability to be driven by remote control fromthe turret or by carrying the remote controller whilewalking alongside the vehicle. For operating over thefull range of available power, two controllers wererequired. These were the remote master controllerand the remote accelerator controller. Both could beinstalled in the turret. If the vehicle was being maneu-vered in close quarters where the power requirementsdid not exceed the engine output at 1300 rpm, onlythe remote master controller was needed. This unit

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on the end of its cable could easily be carried along-side the tank. The remote control feature did not findfavor with the Armored Board who considered it un-necessary and objected to the necessity for lockingthe turret when driving from that position. It wasrecommended that the remote control equipment beeliminated and the stowage space be used for moreessential items.

Service tests of ten production T23s at FortKnox concluded that the tank was unsatisfactory forcombat use. Difficulties in maintenance together withthe retraining necessary for maintenance personnelcombined to cause rejection of the vehicle. A similarrejection occurred in February 1945 when the Euro-pean Theater was informally advised that approxi-mately 200 of the T23s could be made available. Inrefusing these tanks, it was noted that their introduc-tion would require a complete complement of trainedpersonnel as well as a new inventory of spare parts.Such a disadvantage could not be justified at thattime.

The fourth production T23 (serial number 6) during tests atthe G.M. Proving Ground. The pistol port has now reappeared,but this tank is not equipped with lugs for the power trainhoisting device. The vertical volute spring Sherman suspensionwas standard for the production tanks. This vehicle isequipped with double pin T48 tracks.

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The ninth production T23 (serial number 11) at AberdeenProving Ground. The hoisting device lugs are fitted on theright side of the turret.

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Production T23 (serial number 55) during desert tests (aboveand right) near Phoenix, Arizona.

T23 waterproofed and fitted for deep wading tests.

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Scale 1:48

Medium Tank T23, Production Model

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In the view of the turret rear (above left) the radio has not been installed and the rack in the bustle is empty. The right sideof the turret (above right) shows the gunner's seat with the tank commander's lower seat immediately in the rear. Other viewsof turret details are shown below with the 76 mm gun Ml Al and the M62 mount at the bottom.

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The driver's (top left) and assistant driver's (top right) positions are shown above along with hatch details and views of theinstrument panel and remote controllers.Engine compartment cover arrangement and power unit removal are illustrated immediately below. Note the engine andpropulsion generator are removeable as one unit.The photograph at bottom left shows the final drive assembly, while the one at bottom right demonstrates the method ofsetting the track tension using the adjustable idler.

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The pilot T23E3 under test by the Armored Board at Fort Knox, Kentucky.

In April 1943 the Ordnance Committee recom-mended that pilot models of the T23 be constructedusing the torsion bar suspension and it ' designatedsuch pilots as medium tanks T23E3. This action wasapproved in December 1943 and the Chrysler Corpor-ation was authorized to construct two pilot tanks. Achange later limited the construction to only onevehicle. The pilot medium tank T23E3 (registrationnumber 30103068) was completed and delivered tothe Detroit Tank Arsenal on August 29, 1944 forshipment to Fort Knox.

The torsion bar suspension ran on 19 inch widecenter guided tracks and was equipped with six dualroad wheels on each side. The first two and last tworoad wheels on each side were fitted with shockabsorbers and five dual track return rollers were pro-vided for each track.

The turret and much of the equipment used inthe construction of the T23E3 were obtained fromproduction T23 number 19, whose registration num-ber it also acquired. This vehicle had been manufac-tured at the Detroit Tank Arsenal and was diverted tothe Tank Laboratory for disassembly. T23 number 19

was manufac tu r ed before the water proofingspecifications were released, however, all the elec-trical equipment was water-proofed before being in-stalled in the T23E3. The turret was also brought upto date by removing the basket and relocating theequipment previously supported by the turret plat-form. The track and suspension used on the new pilotwere obtained from a T25E1 medium tank at Aber-deen Proving Ground. A new hull was manufacturedfor the T23E3 and the original hull from T23 number19 was shipped to Aberdeen Proving Ground forballistic tests. After completion, the tank was shippedto the Armored Board at Fort Knox. However, noproduction resulted due to lack of interest in electricdrive tanks.

In July 1943, it had been proposed to stand-ardize the T23E3 as the medium tank M27 with theelectric drive and torsion bar suspension. At the sametime it was proposed to standardize the T20E3 as themedium tank M27B1 with the torqmatic drive andtorsion bar suspension. An OCM item was drafted,but standardization was not approved.

The T23E3 pilot after completion at Chrysler in August 1944.

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The photographs above and to the right show the pilot T23E3shortly after completion at Chrysler. Unlike the earlier T20E3,this tank has a 13 tooth sprocket. Stowage was also modern-ized to the latest practice, including the addition of acamouflage net rack on the right side of the turret. The box onthe left side of the turret, just forward of the pistol port, wasfor stowage of a first aid kit.

At the left, the T23E3 is fitted with a double pin centerguided track. Note that the sprocket has also been modified.

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Scale 1:48Medium Tank T23E3, Pilot

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The driver (top left) and assistant driver (top right) wereequipped with same controls as in the production T23. A can-vas cover has been placed over the .30 caliber bow machinegun. The turret stowage (center) was modified to conform tothe design practice of August 1944 with the ready rounds heldin a rack suspended from the turret ring. The turret basket wasremoved and the gunner's seat (bottom) suspended from theturret ring. The ammunition was stowed in floor racks madeaccessible by the elimination of the turret basket.

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A further variation in suspension systems wasproposed for the T23 with the introduction of thepilot medium tanks M4E8. These vehicles wereequipped with horizontal volute spring suspensionsand 23 inch center guided tracks. The OrdnanceCommittee recommended that a pilot medium tankT23 be built with this suspension system anddesignated such a pilot as the medium tank T23E4.The Corps of Engineers objected since the vehiclewould be 131 inches wide, exceeding by seven inchesthe permissible width under AR850-15. Because ofthis excess width, the procurement of the pilot wasdisapproved. However, at a later date, threeproduction T23s were fitted with the horizontalvolute spring suspension and 23 inch T80 tracks andshipped to Fort Knox for test purposes. The testsreported, not surprisingly, that the wide trackhorizontal volute spring suspension was superior inperformance to the standard 16-9/16 inch track andvertical volute spring suspension as provided on thestandard medium tank T23. Again, no productionresulted due to the end of the war and lack of interestin the electric drive vehicles.

The four views at the left show one (registration number30112588) of the three production T23s modified to use thehorizontal volute spring suspension and center guided track.The tanks were under test by the Armored Board and werefitted with the T80 double pin track. The guns on these tankswere equipped with muzzle brakes and a later type of travelinglock.Another of the three tanks (registration number 30112590) isshown below in its final resting place at Aberdeen ProvingGround.

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Scale 1:48

Medium Tank T23 HVSS

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T25 pilot number 1 at Chrysler in January 1944. The same tank is shown below with the hatches open.

THE T25 AND T26

At the time production was authorized for theT23 medium tank, 50 of these vehicles were re-quested modified to mount the 90 mm gun. Fortytanks, using the same armor basis as the T23, weredesignated medium tank T25. The remaining ten ve-hicles were to be equipped with heavier armor anddesignated medium tank T26. The latter was ex-pected to equal the firepower and protection of theGerman Panzerkampfwagen VI Tiger I and still main-tain a lower vehicle weight. The original design esti-mates indicated a weight of 72,000 pounds for theT25 and 80,000 pounds for the T26. However, con-tinued development showed an increase in weight forthe T25 to about 81,000 pounds and a similar largeincrease for the T26. Since a great portion of theweight was due to the electric transmission, a decisionwas made to replace the electric drive with a torq-ma t i c transmission. The modified designs weredesignated medium tanks T25E1 and T26E1 and theywere selected to fill the production order for 50 tanksin place of the previous models.

Following the decision to change the limitedprocurement order to the T25E1 and T26E1, it wasrequested that two T23s be converted to the originaldesign concept for the T25, mounting a 90 mm gunturret. Medium tank T25 pilot number 1 (registrationnumber 30103053) was completed by the ChryslerEngineering Division and delivered to Detroit TankArsenal for shipment to Aberdeen Proving Ground onJanuary 21, 1944. T25 pilot number 2 (registrationnumber 30103054) was completed and delivered tothe Tank Arsenal for shipment to Fort Knox on April29, 1944. Pilots 1 and 2 weighed 82,310 lbs. and84,210 Ibs. respectively. Both vehicles were equippedwith the horizontal volute spring suspension and the

23 inch center guided track. The major portion of theweight difference was due to a weight increase in thesuspension and tracks as a result of redesigning themain brackets, increased tire thickness, and changingthe track sections. The balance of the difference maybe attributed to numerous minor changes andvariations in casting thickness.

The T25s carried a 90 mm gun T7 and a coaxial.30 cal. machine gun mounted in a larger, T25E1 typeturret. The 90 was not equipped with a stabilizer ineither the T25 or T26. The hull differed from that ofthe T23 in having longer and narrower drivers' hatchopenings to provide clearance past the gun shieldwhen opening the doors with the gun forward. It alsohad a stronger ribbed roof casting to support theheavier turret assembly. The 3 inch thick hull frontwas a welded assembly of castings and rolled plateidentical in appearance to the production model T23.Rear hull braces were eliminated to provide moreammunition stowage space. The power plant andpropulsion equipment consisted of the Ford V-8Model GAN tank engine with electric drive, identicalwith the T23. Testing of the medium tank T25 beganat the Armored Board on September 28, 1944. Bythis time, interest was centered on the heavier T26E1vehicle and at the conclusion of the tests, it wasrecommended that no further consideration be givento medium tank T25.

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T25 pilot number 1 under test at Aberdeen Proving Ground.Pilot number 1 had no pistol port and was not fitted with anet stowage rack on the right side of the turret. The guntraveling lock was the open top type, similar to that on theT23 early production tanks. The horizontal volute spring sus-pension with the 23 inch T66, center guided, single pin trackcan be seen clearly in these views. Note that shock absorbersare mounted on all three bogies. Only the two large trackreturn rollers are visible in the photographs. In addition, therewere three small return rollers per track, one directly aboveeach bogie.The turret arrangement shown below was a larger, heavier ver-sion of the T23, retaining the vision cupola for the tank com-mander and the rotating hatch for the loader. The 90 mm gunwas not equipped with a muzzle brake on either T25 pilot.

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Scale 1:48

Medium Tank T25, Pilot Number 1

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Pilot number 2 under test by the Armored Board at FortKnox. As happened frequently during these tests, the sand-shields have been removed. The tow cable has also been lostalong the way and the tank is now equipped with T80 doublepin tracks. However, six T66 single pin track blocks are stillcarried on the front armor plate.

T25 pilot number 2 at Chrysler in April 1944. The tank isreadily identified by the turret net stowage rack and pistolport. A closeup at the left shows the traveling gun lock similarto that on the late production T23. Note the weld metalarrows on the rear hull to indicate proper stowage of the tow-ing cable. The words START and FINISH are partiallyobscured by the cable itself.

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The view through the tank commander's hatch is compared above for T25s pilot number 1 (left) and pilot number 2 (right).The partial turret basket was removed on pilot number 2 and the floor ammunition stowage rearranged. The gunner's seat wassuspended from the turret ring on the later vehicle. The recoil guard and breech of the 90 mm gun is visible at the left of eachphotograph.

The loader's station is compared for pilot number 1 (below)and pilot number 2 (right). On pilot number 2 the 90 mmrounds were enclosed in canvas containers. One 90 mm highexplosive shell is shown in the ready rack of pilot number 1.

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The driver's (left) and assistant driver's positions are shown above for pilot number 2. Note the similarity to the lateproduction T23. The controls were identical.Further details of the turret stowage arrangements on pilot number 2 are illustrated below. At the loader's station (left) the.30 caliber coaxial machine gun is clearly visible with its ammunition box. The 2 inch smoke mortar is in the open positionbetween the machine gun and the 90 mm ready round. The radio and other bustle stowage are shown immediately below(right) followed by the gunner's station (bottom right).

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Although the T26 was eliminated in favor of theT26E1 for the limited procurement order of tentanks, the Office, Chief of Ordnance, authorized theprocurement of pilots according to the original T26concept for test purposes. These vehicles were to beequipped with the electric drive and a torsion barsuspension.

The original directive from the OrdnanceDepartment authorized the building of two T26pilots. However, the construction program wasreduced to one on May 6, 1944. This tank,(registration number 30128307) was delivered by theTank Laboratory of the Chrysler Engineering Divisionfor shipment to Fort Knox on October 28, 1944. Itscombat weight was 95,100 pounds. The torsion barsuspension and the 24 inch track were salvaged froma T26E1 at Aberdeen Proving Ground and a fewmodifications were made prior to its installation. Thepower plant and electric drive were identical to thesystem in the medium tank T23. Front hullconstruction differed somewhat from the T25,consisting of a welded assembly of rolled platessimilar in appearance to the T23 pilot models. Thefront hull armor was 4 inches thick at angle of 46degrees from the vertical. The T26E1 type turretmounting the 90 mm gun was modified to remove thebasket and to make other changes in accordance withthe latest turret design.

The T26 was placed under test at Fort Knox,starting on November 30, 1944, in comparison withthe T26E1 and the later model T26E3. The T26 wasfound to be superior in normal terrain operation.However, the T26E1 and T26E3 were superior inreliability, ease of control on steep winding grades,and had smaller maintenance requirements. TheArmored Board concluded that the fast forward andr e v e r s e s p e e d s , qu i ck accelera t ion , and

T26 pilot at Chrysler in October 1944.

maneuverability of the T26 over normal terrain weresuperior to that of the T26E1 or the T26E3, but theelectric drive was too complicated for the averagemechanic to understand or repair. This reflected thegeneral attitude at that time toward the electric drivetanks. As a result of these conclusions, no furtherwork was done on the T26.

T26 pilot under test at Fort Knox.

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The T26 turret was similar in design to the T25, with thickerarmor, and was fitted with a pistol port. The same arrange-ment of a vision cupola for the tank commander and the rotat-ing hatch for the loader was retained. The camouflage netbracket appears to be overloaded in these views. This mayexplain the Armored Board's objection to the location of therack. Their complaint was that the rack obscured the viewfrom the vision cupola and this was certainly true if it waspoorly stowed as shown in the top photograph. The 90 mmgun did not have a muzzle brake on this vehicle. The T26E1torsion bar suspension with the 24 inch T81 single pin tracks isclearly visible in these photographs. Note the extra T81 trackblocks fixed to the front armor below at the right. This viewalso shows the front hull construction which was welded upfrom sections of rolled plate. Once again the sandshields havebeen partially removed during the tests at Fort Knox.

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Scale 1:48Medium Tank T26, Pilot

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Detai ls of the outside stowage boxes can be seen in the twoviews at the right. The upper photograph also shows the pistolport in the open position.The rear hull and the gun traveling lock are shown below atthe right. The opening below the gun travel lock support is theengine exhaust. Like the T25, the tow cable was stowed on therear hull.Directly below is a view through the loader's hatch showingthe ten round ready rack for the 90 mm gun. The coaxial .30caliber machine gun appears at the upper right in the photo-graph. Note there is no turret basket in this vehicle and thecovers of the floor ammunition stowage boxes can be seen justbelow the ready rack.

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T25E1 number 1 (above and below) at Aberdeen Proving Ground on March 8,1944.

THE T25E1, T26E1, AND M26 (T26E3)

Deliveries under the limited procurement orderfor 40 T25Els and ten T26Els began in Februaryand ran through May 1944. The first tank, aT25El,was demonstrated on January 13. All 50 vehicleswere built at General Motors Fisher Tank Arsenal,Grand Blanc, Michigan. Of the first T25Els off theproduction line, three were shipped to AberdeenProving Ground, two to the General Motors ProvingGround, one to Phoenix, Arizona, and five to theArmored Board at Fort Knox. The first T26E1 wasforwarded to Aberdeen Proving Ground in Februaryfollowed shortly by number 2.

At a later date, T26E1 number 5 was shipped toFort Knox for evaluation by the Armored Board. Theregistration numbers ranged from 30103252 through30103291 for the 40 T25Els and from 30103292through 30103301 for the ten T26Els. The twomodels were quite similar in appearance andconstruction, both being equipped with the FordGAF tank engine and torqmatic transmission. The70,000 Ib. unstowed weight of the T25E1 rose to81,300 Ibs. for the T26E1, due to the latter's heavierarmor. This in turn required an increase in trackwidth from 19 to 24 inches and a change in the finaldrive gear ratio.

The hull was an assembly of armor steel castingsor sections welded to rolled armor plate. A singlelarge V-shaped casting was used for the front hull inboth tanks, differing only in thickness. The upperfront was 3 inches thick on the T25E1 and 4 inchesthick on the T26E1, both at 46 degrees from thevertical. The V-shaped front casting was welded to

the floor at the bottom and extended up and backpast the drivers' hatches to form the front of theturret ring opening. The bulge for the .30 caliber bowmachine gun mount was an integral part of thecasting. The rear of the turret ring opening wasformed by the rear upper hull casting which extendedacross the width of the tank. Both castings werewelded to the center upper hull plates and the hullside plates. The cast rear hull side plates, containing alarge machined hole for the final drives, were weldedbetween the hull side plates and the hull rear plate.The floor side plates were welded to the hull floor atan angle slanting upward to meet the hull side platesgiving a boat shaped bottom to the hull. The wheelarm supports extended through openings in the floorside plates and were bolted to the outside.Crossmembers were welded to the inside hull floorfor reinforcement and to support equipment abovethe torsion bars. On top of the hull, a cast transverse

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All three photographs on this page show T26E1 number 1 under test at Aberdeen Proving Ground. This was the tank latermodified to mount the 90 mm T15E1 gun and then shipped to Europe.

housing extended across the center of the enginecompartment and was bolted to the side plates tostrengthen the structure. A curved bulkhead waswelded in place to separate the fighting compartmentfrom the engine compartment and to support the hulltop plate and rear section of the turret ring. Twoescape hatches, one in front of each driver's seat,provided emergency exits.

Dual controls for the driver and assistant driverwere mounted in the left and right front hullrespectively. Since the controlled differential waslocated at the rear of the engine compartment, thesteering levers were connected by a series of linkagerods extending to the rear between the ammunitionstowage boxes. A .30 caliber M1919A4 machine gunin the bow hull mount was operated by the assistantdriver. No sights were fitted on this weapon andtracers were used for aiming, with the fire beingobserved through a periscope. Four M6 periscopeswere installed, two for the driver and two for theassistant driver. Each man had one periscope in hishatch cover and one in the hull roof just inboard ofhis hatch. Adjustable seats permitted the drivers toride with their heads out when the hatches were openor, in the lowered position, to observe through theperiscopes with the hatches closed. Ventilation forboth the driving and fighting compartments wasprovided by the 400 cfm rotoclone blower located onthe hull roof between the drivers. The blower and itsintake caused the large bulge in the top center of thefront armor casting.

The gun travel lock pivoted on the exhaust casting is clearlyvisible in the photograph above. Also, note the different towcable stowage compared to the T25 and T26.

Details of the massive T26E1 turret can be seen above. The .50caliber machine gun on the loader's hatch is locked in its travelposition with the muzzle held by the retaining clip.

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T25E1 number 4 under test at the General Motors ProvingGround. Without sandshields, the suspension details are clearlyvisible. Note the shock absorbers on the first two and last tworoad wheels. The photograph at the left gives a good view ofthe sprocket showing how it engaged the lugs at the end ofeach track link. These views also show the 90 mm gun lockedin its travel position.

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The photograph above and the two views at the left showthree T25Els, numbers 1, 6, and 8, during test operations atAberdeen Proving Ground. The suspension diassembly abovereveals considerable detail including the volute bumper springsused to limit the travel of each road wheel arm. Note theheavy wear on the sprocket teeth.The view below was taken at Fort Knox, Kentucky duringtests by the Armored Board. This is T25E1 number 21. The601 on the turret was the Armored Board number assigned tothe test vehicle.

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T26E1 number 4 on test at the General Motors ProvingGround. The number 8537 was assigned to the vehicle by theProving Ground. Similar four digit numbers can be seen onother vehicles tested at General Motors. The T81 single pintracks are shown clearly in the two upper views. At the left,the sprocket can be seen engaging the holes near the end ofeach track link. Compare this with the similar view of theT25E1.

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Sectional view showing stowage in medium tanks T25E1 and T26E1. Note that all 90 mm ammunition is stowed below thefighting compartment floor.

The Pershing was a tight fit when it came to crossing bridges.This is one method (at right) of crossing a 60 ton Baileybridge. The heavy timbers were used to protect the bridgecurbs.

The photographs at the left show a race over a 4.3 mile coursein the Churchville cross country area at Aberdeen ProvingGround between medium tanks T26E1, T25E1, M4A3E8, andthe M4A3 with the standard vertical volute spring suspension.The top view shows T25E1 number 6 passing T26E1 number 2.

The T25E1 had the best recorded time of 23 minutes followedby the T26E1 with 26 minutes. The M4A3E8 and M4A3finished in 28 minutes 35 seconds and 30 minutes 40 secondsrespectively. A T23 was also in the race, but threw a track anddid not finish.

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Scale 1:48Medium Tank T25E1

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Scale 1:48Medium Tank T26E1

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The arrangement of the engine compartment is diagramedabove showing the location of the fuel tanks and power traincomponents. Front (top left) and rear (center left) views ofthe Ford GAF engine are compared here. The flywheelhousing bolted directly to the transmission reduction gearunit. The complete power train is shown in the lower photo-graph.

The power unit, consisting of the Ford GAFengine, torqmatic transmission, and controlleddifferential, was installed in the engine compartmentand was removeable as a single assembly. Two fueltanks were mounted, one on each side of the engine,at the forward end of the compartment. The coolingunit, removeable as a single assembly, was attached tothe cast transverse housing, with the fans fitting oneach side of the transmission.

The model GAF engine, quite similar to theGAN used in the T23, was a 60 degree V-type, eightcylinder, four cycle, gasoline power plant developing500 gross horsepower at 2600 rpm. The torqmatictransmission was an improved version of the modelfitted to the T20 and T20E3. It consisted of theplanetary reduction gears bolted to the engineflywheel, the torque converter which served as a fluidclutch, and the transmission planetary reduction gearswhich provided the three forward and one reversegear ratios. Bolted to the rear cover of thetransmission was the controlled differential whichtransmitted power through universal joints to thefinal drives and provided for steering and braking thevehicle.

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The final drives were bolted to the outside ofthe hull side plates at the rear of the tank andtransmitted power from the differential to the tracksprockets. Each final drive consisted of a final drivepinion shaft, a pinion and gear, a final drive shaft, anda final drive housing. The final drive shaft was flangedat the outer end and provided with studs formounting the track sprocket hubs. The gears andbearings inside the final drive housing operated in acontinuous oil bath.

The power unit consisting of the engine, transmission, andcontrolled differential could be removed as a single assembly(above). At left, the remaining components are exposed in theengine compartment. The control rods and cables can be seenalong the compartment floor. The driving controls are dia-gramed immediately below and at the bottom of the page, thedriver's station is shown at the left and that of the assistantdriver is at the right.

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The boat shaped bottom of the Pershing hull is clearly revealedin this view from the lower rear of the tank. The engine com-partment drain covers can be seen, as well as the drivers'escape hatches at the front end. The road wheel arm supportsare bolted to the floor side plates.

The details shown on the T25E1 suspension above applyequally to the T26E1 except for the wider tracks and heavierduty components of the latter vehicle.

In appearance the torsion bar suspension systemwas quite similar on the T25E1 and T26E1. However,the greater weight of the latter vehicle requiredheavier duty components and the 19 inch track widthof the T25E1 was increased to 24 inches. Both tanksrode on 12, 26 inch diameter, rubber tired, dual roadwheels, six for each track. Although the samediameter, the wheels for the T26E1 were wider andof heavier construction. Each dual road wheel wasbolted to the road wheel hub mounted on twotapered roller bearings on each road wheel armspindle. In turn, the road wheel arm was supportedon two needle bearings in a road wheel arm support.These road wheel arm supports also provided seats forthe torsion bar anchor plugs for the end of thetorsion bar extending from the opposite side of thevehicle. The torsion bars, made of spring steel, rancrosswise from the road wheel arm to the anchor plugin the opposite road wheel arm support. Springingaction to support the weight of the tank was obtainedfrom the torsional resistance of the bar when twistedby the up and down movement of the road wheel armand spindle. Volute type bumper springs acted asstops for each road wheel arm. Hydraulic shockabsorbers controlled the movement of the first twoand last two road wheels on each side of the tank.The track idler wheel was supported on an eccentricspindle in the upper end of the front road wheel arm.The spindle position could be moved to adjust thetrack tension. When the front road wheel struck anobstacle and moved upward, the arm pivoted on thefront road wheel arm spindle moving the idlerforward and down, thus maintaining the tracktension. The upper section of each track was carriedon five dual track support rollers mounted onbrackets bolted to the hull side plates.

All steel, single pin tracks were used for bothvehicles differing slightly in design. On the 19 inchwide T25E1 tracks, the sprocket engaged the lugs ateach side of the track shoes. With the wider T26E1tracks, the sprocket teeth entered holes at each endof the track shoe. There were 82 shoes per track witha six inch pitch for both tanks.

The track tension is being adjusted at left above. At right above, the single pin track link assemblies are compared for theT25E1 (left) and T26El (right). The overall width of the T26E1 link was 24 inches and this track was designated the T81.

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Views of the turret hatches from the front show the tank commander's cupola(top left) and the loader's rotating ring hatch (top center). Note the port for the2 inch smoke mortar just in front of the loader's hatch. The turret bustlestowage just behind the loader's position (top right) illustrates the ready accessto ammunition for the machine guns and smoke mortar. The opposite side of theturret bustle (below) contained the radio located next to the tank commander.

A distinguishing feature of both tanks was theheavy cast turret set well forward on the hull. Itreflected many of the same design characteristics asthe T23 which paralleled it in production, althoughheavier and larger to accommodate the 90 mm gun.The turret sides and rear were 2Vz inches thick for theT25E1 compared to 3 inches for the T26E1. Asemicircular rotating platform and a partial basketwere suspended from the right side of the turret. Theinside diameter of the turret ring was the same 69inches as on the other T20 series tanks, as well as theSherman. The large turret bustle needed to balancethe long 90 mm gun provided stowage space for theradio equipment.

A six block vision cupola was mounted over thetank commander's position on the right side of theturret. In addition, the cupola hatch carried astandard M6 periscope in a rotating mount. In frontof the tank commander, the gunner's M8A1 periscopewith a built in telescope was fitted through the turretroof and coupled to the gun mount. The gunner wasalso equipped with an M71C telescope in the gunshield, coaxial with the 90 mm gun. At the left of thegun, a circular double door hatch was provided forthe loader with a revolving ring mount for a .50caliber antiaircraft machine gun. A rotating M6periscope was located in one of the hatch doors. Theport for the 2 inch smoke mortar M3, appeared justforward of the loader's hatch. The mortar, used forlaying smoke screens, was fixed in the turret roof andtraversed by rotation of the turret. Range could beset at approximately 35, 75, or 150 yards by use ofthe regulator on the mortar controlling the escape ofpropellant gases.

The gunner's station as viewed from the tank commander'shatch. Note the floor of the partial turret basket under thegunner's seat.

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The T99 and T99E1 combination gun mountswere fitted to the T25E1 and T26E1 respectively.The only difference was a maximum armor thicknessof 3l/2 inches for the T99 and 4l/2 inches for theT99E1. Both carried the 90 mm gun T7, with a .30caliber machine gun M1919A4 in a coaxial mountjust to the left of the main weapon. Elevation rangedfrom +20 to -10 degrees, but no stabilizer was fitted.Turret rotation provided a 360 degree traverse eithermanually or by a hydraulic drive. The 90 mm guncould be fired electrically by the trigger on the powertraverse control handle or by a foot switch on theturret floor. A manual firing pedal was also providedin case of electrical failure. Another electric footswitch fired the coaxial machine gun, which couldalso be fired manually by the loader, using theconventional trigger.

Forty-two rounds of 90 mm ammunition werestowed in two water protected bins under the floor ofthe fighting compartment. Access to the ammunitionrequired that the turret be traversed until the rotatingsemicircular platform exposed the correct bin. Thecover could then be opened and the ammunitionremoved.

The gun mount recoil cylinders are visible in the view at rightfrom the loader's position. Note the coaxial .30 calibermachine gun and the roof mounted 2 inch smoke mortar atthe left of the photograph.

Above is the 90 mm gun T7 and below the same weapon isshown in the combination gun mount T99E1.

The floor stowage compartments for the 90 mm ammunitionare fully exposed below with the turret removed. The 90 mmammunition was placed in compartments B, C, D, and E.Details of the water tanks which provided the "wet stowage"are shown in the two views at the left. These tanks acted asdividers in the ammunition compartments and were alsoplaced at each end along the side walls of the tank hull.

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With the arrival of the first tanks at Aberdeenand Fort Knox, an intensive test program began todiscover any defects in the vehicles and make anynecessary changes. One result of these tests was achange in the steering ratio from 2.08:1 to 1.79 to 1.The change increased the minimum turning diameterby about 20 feet.

The initial testing of the first and secondT26E1s was completed on May 21, 1944 andAberdeen concluded that the vehicle design wasbasically sound and that the torqmatic transmission,torsion bar suspension, and 90 mm gun weresatisfactory. Major problems were poor cooling of thedifferential, repeated failures of the connectionbetween the engine and flywheel, plugging of theradiators cores with dirt, oil leaks, and poor 90 mmammunition stowage. The latter also raised seriousobjections at Fort Knox. First, the 42 rounds carriedwere considered insufficient as the ETO wanted atleast 70 rounds and second, the stowage bins underthe turret platform were far too inaccessible. Testsalso revealed that the semicircular rotating platformunder the gunner and tank commander interferedwith the loader during firing. Several solutions to theproblem were considered, one of which eliminatedthe assistant driver and replaced him with an 18round ammunition rack. However, the ETO ruled thisout by insisting on the retention of the bow machinegun. The final design removed the rotating platformand turret basket, retaining only a small foot rest forthe gunner. The floor ammunition racks were en-larged and the water protection sacrificed to obtainadditional ammunition space. Racks were installed oneach side of the fighting compartment as well as aready rack on the loader's side of the turret. With thenew arrangement, 70 rounds of 90 mm ammunitioncould be carried.

Firing tests at Fort Knox showed a severeobscuration problem with the 90 mm gun. So muchdust was kicked up by the muzzle blast that the 90was condemned as a one shot weapon, because of thelong delay before it was possible to see well enoughto fire again. The cure recommended was a muzzle

brake which would deflect the blast sideways re-ducing the obscuration along the line of sight.

Ground pressure on the T25E1 was consideredtoo high with the narrow 19 inch tracks. ArmoredBoard tests showed the necessity for wider tracks andit was recommended that the complete suspension ofthe T26E1 be installed. In addition to the 24 inchwide tracks, the heavier duty components weree x p e c t e d t o great ly reduce ma in tenancerequirements. However, by the summer of 1944,interest had shifted to the T26E1 with its heavierarmor plate and no production was approved for theT25E1. Allied troops in Normandy were running intoincreasing numbers of heavily armored enemyfighting vehicles and were calling for more firepowerand greatly increased protection. This combatsituation killed any further interest in the T25E1 andstimulated the development of even more heavilyarmored vehicles even though the horsepower toweight ratio suffered accordingly. The desire for aheavy tank even led to some name changing. On June29, 1944, all models of the T26 series wereredesignated as heavy tanks and remained so untilafter the war, when the original designation of amedium tank was restored. Throughout this narrativethey will be considered as medium tanks.

In Janua ry 1944, Ordnance had receivedpermission to build 250 T26Els beyond the initialten pilot tanks. The lessons learned from the pilottest program were applied to the production of thesevehicles beginning in November at the Fisher TankArsenal. With these improvements, the tank wasredesignated as the T26E3. The serial numbers of the250 tanks were 11 through 260, since serials 1through 10 were applied to the T26E1. Theregis t ra t ion numbers were 30119821 through30120070.

To check the various modifications, T25E1number 5 (registration number 30103256) was con-verted to the T26E3 standard. The turret was modi-fied to the latest design practice by replacing therevolving hatch over the loader's position with a smalloval hatch. The .50 caliber machine gun was moved

T25E1 number 5 modified to T26E3 standard. The 90 mm gun is fitted with a muzzle brake and is carried in thecombination mount T99E2.

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to a pedestal mount at the rear of the turret roof. Thecombination mount T99E2 was installed carrying the90 mm gun with a double baffle muzzle brake. Thismount was later standardized as the M67. The turretbasket was removed and the stowage arrangementsreworked to the new standard. Brackets were weldedto the turret which allowed the installation of ahoisting device for removing the power train.

The modified T25E1 number 5 with the gun locked in thetravel position. A steel plate has been welded into the openingfor the large rotating loader's hatch and a small oval hatchinstalled.

Eclipsed by the desire for heavier armor, theT25E1 was limited to use as an experimental vehicleand some served in this role even into the postwarperiod. The 90 mm gun T14 in the combination gunmount T102 was tested in the T25E1 during May andJune 1945. This mount used a concentric recoilmechanism which occupied much less space than thestandard double recoil cylinders. As the name impliedthe recoil chamber encircled the gun tube itselfreplacing the separate cylinders spaced about thecircumference of the tube. With the increased spaceavailable, two coaxial .50 caliber machine gunsreplaced the single .30 caliber weapon on thestandard mount. The 90 mm gun T14 was fitted witha muzzle brake and was ballistically identical with thestandard M3 gun.

T25E1 number 1 (at left) with the 90 mm gun T14 in con-centric recoil mount T102. The .50 caliber machine gunbarrels protruded through the gun shield (bottom left) andfrequently served as hand holds for the driver when entering orleaving the tank. The arrangement of the two coaxial guns andthe telescopic sight in the T102 mount are shown above. Toprovide space for the .50 caliber machine gun ammunition, the90 mm ready rack (below) was limited to 8 rounds.

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T25E1 number 13 with the integrated fighting compartment.The modifications required a new turret roof of increasedheight to provide space for the rangefinder. Eyepieces andcontrols for the rangefinder T31 are shown in the interior viewbelow.

As late as 1948, T25E1 number 13 (registrationnumber 30103264) was used to study the advantagesof an integrated fighting compartment equipped witha turret range finder and a lead computer. Thesestudies led directly to the development of the moresophisticated postwar fire control systems. Manyother experimental combinations of armament wereproposed and one proposal drawing even shows the105 mm gun T5E1 mounted on a T25E1 tank withan enlarged turret ring.

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A proposal drawing for the T25E1 fitted with the 105 mm gunT5E1. This is the same weapon installed on heavy tank T29and the turret ring has been enlarged in this drawing to thesame 80 inches used on the T29. MED. TANK T25E1 MODIFIED

TO MOUNT 105MM GUN

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The second production T26E3 (serial number 12) at Aberdeen Proving Ground (above and below) on December 12, 1944.

A f t e r correct ing most of the problemsuncovered by the test program, the T26E3 went intoproduction at the Fisher Tank Arsenal in November1944 and the first 10 vehicles were delivered by theend of the month. Production rapidly increased with30 vehicles delivered in December, 70 in January and132 in February 1945. In March, production alsostarted at the Detroit Tank Arsenal and the combineddelivery for the month was 194 tanks. This increasedto 269 in April, 361 in May and 370 in June. By thistime, the end of the war in Europe had reduced theproduction schedule, although over 2000 wereproduced by the end of 1945. After its successfulintroduction into battle, the T26E3 was standardizedas the M26 in March 1945. The first vehicles wereequipped with the 24 inch T81 track of the T26E1,but later production was fitted with the 23 inchT80E1 track, similar to that on the M4 with thehorizontal volute spring suspension.

The 90 mm gun T7, mounted in the T25 andT26 series vehicles, was standardized as the 90 mmgun M3. This weapon was developed from the 90 mmantiaircraft gun modified for use in a tank mount. Itsballistic performance was identical to that of theantiaircraft gun and it used the same ammunition. Amuzzle velocity of 2650 ft/sec was obtained withexplosive loaded, armor piercing, capped ammunition(APC M82). This was later increased to 2800 ft/secby using a larger powder charge, but few of theserounds reached the troops in time for use duringWorld War II. Improved performance was obtainedusing armor piercing composite rigid (APCR)ammunition consisting of a lightweight shot with atungsten carbide core. These projectiles, designatedHVAP-T 90 mm T30E16, achieved a muzzle velocityof 3350 ft/sec and would penetrate 6.1 inches ofhomogeneous armor at 2000 yards and 30 degreesobliquity. Despite this performance, the highly sloped

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T26E3 serial number 204 is shown in the three upper photo-graphs at the right during tests at the General Motors ProvingGround. This tank was produced at the Fisher Tank Arsenal inJanuary 1945 and is still equipped with the T81 track. Notethe stowed position of the .50 caliber machine gun pedestal.

frontal armor of the German Panzerkampfwagen VPanther presented a difficult target. The M3 gun usingT30E16 shot could penetrate the Panther's glacisplate only up to a dangerously close range of 450yards. To help solve this problem, a shot wasdeveloped particularly for such high obliquity targets.This was the 90 mm AP-T shot T33 which wasmanufactured from the substitute standard monoblocshot M77. The M77 projectile was reheat treated to ahigher hardness level and fitted with a windshield toimprove its exterior ballistics. With the T33 shot, theM3 gun had a muzzle velocity of 2800 ft/sec, but itcould penetrate the Panther's glacis up to a range of1100 yards. Limited quantities of both the T30E16and the T33 ammunition were available for thePershings introduced by the Zebra mission. Theeffectiveness of both types in action has been des-cribed earlier.

Parallel with the T26E3's introduction to battleby the Zebra mission, 20 tanks were shipped to FortKnox for test. These tests revealed that mostproblems with the T26E1 had been solved. However,one serious defect remained, a dangerously weakelevation housing on the 90 mm gun. A stiffener platewas added as a quick fix in production until astronger forged housing could be procured.

Tests both at Fort Knox and Aberdeen showedthat the ventilation provided by the rotoclone blowerwas inadequate to clear powder fumes from the tankwhen firing. A 1000 cfm blower was recommended toreplace the 400 cfm unit. The change required a newfront casting to house the larger fan. Previous ballistictests had shown the bulge over the rotoclonesomewhat weaker than the rest of the front plate. Inthe design of the new front casting, this area wasthickened to improve protection in this region. Thenew casting was introduced into production withtank number 550 at Fisher and number 235 atChrysler. At the same time, a study was started toconsider remounting the ventilator in the rear of theturret bustle. However, this did not come about untilthe postwar medium tank T42. Research continuedinto improved cooling, better ballistic protection forair intakes and grilles, and better vision devices.Particular attention was given to the problem ofincreasing the ballistic protection of the gun shield,which was considerably weaker than the rest of thefront armor. However, only minor changes were madein the standard M26 shield before production ended,such as a reduction in the clearance between theshield and the gun barrel to minimize jamming bysmall arms fire.

The M26 below is serial number 1602 produced at Fisher. Thistank is equipped with the 1000 cfm rotoclone blower. Thedifference in the front armor casting is apparent when com-pared with serial number 204 above.

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Sectional view of the production M26. Compare the increased ammunition stowage with the earlier version on page 109.

The production M26 in the two photographs below is fittedwith the T80E1 double pin track. Details of this track can beseen on the four blocks attached to the tank turret.

Attempts to improve the performance in mud led to variationsin the design of the track blocks. A modified T81 single pintrack is under test below. The T91 double pin track with largergrousers is shown above.

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Scale 1:48

Medium Tank M26 (T26E3)

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The dimensions of the production M26 hull are shown in these drawings. The welding diagram (below left) indicates themanner in which the hull was assembled from the armor castings and rolled sections.

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Production line of Pershings (right) at the Fisher Tank Arsenalduring the winter of 1944-45.

Details of the commander's vision cupola are shown above.The other views show the relative location of items on the topof the tank. The bottom photographs detail the loader's hatchin the open and closed positions.

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The two top photographs give a general view of the gunner'sstation. Note the replacement of the turret basket by the smallfoot rest marked C. Compare with the T26E1 on page 115.The general arrangement of the turret is shown in the drawingbelow.

The components of the SCR528 radio were located (above) inthe turret bustle just behind the tank commander.The ready rack (at left) provided ten rounds of 90 mmammunition for immediate use at the loader's position.With the turret removed, the floor stowage compartments canbe seen open and closed in the bottom photographs.

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The 90 mm gun M3 is shown at the above left in combinationmount M67. The .30 caliber coaxial machine has not beenfitted in this photograph. The 90 mm gun removed from themount appears above at the right.

Above is a closeup of the muzzle brake M3. The insert in thesecond baffle is replaceable when eroded.The traveling lock for the 90 mm gun is shown in both posi-tions at the left. Also, note the towing pintle in the stowedposition.

HVAP T30E16 (APCR-T) AP T33 (APBC-T)

Projectile types are shown at the left from top to bottom, (A) APC (APCBC/HE-T), (B) APC (APCBC-T), (C) AP (AP-T), and(D) HVAP (APCR-T). The two complete 90 mm rounds in the upper photograph at right are AP T33 (APBC-T) at the topand HVAP T30E16 (APCR-T) at the bottom. Details of the projectiles for these rounds are shown in the lower pictures.

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Above: The driver's position at the left and the assistantdriver's position at the right.The control console is shown at the left with a closeup view ofthe instrument panel below.

Above: The bow machine gun operated by the assistant driver.Left: These two views show details of the drivers' hatches.Below: One of the two escape hatches located in front of thedrivers' seats.

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Above: M26 suspension fitted with the T80E1 double pintracks. The links for the T80E1 track are shown below. Com-pare with the single pin track on page 114.

The turret mounted hoisting device for removing the powerunit is demonstrated at the right on T26E1 number 1.Below: Attempts to increase the range of the Pershing resultedin experiments with jettisionable fuel tanks. As shown in thesephotographs, the T25E1 was again used as the test vehicle.

Above: Production line assembly of the M26 at Fisher TankArsenal reveals details of the suspension system. The shockabsorbers and volute bumper springs are clearly visible.

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Two 18 ton inflatable bridge pontons are used above to float the Pershing.

During its service career, the Pershing wasmodified and fitted with a great variety of equipmentto improve its mobility and firepower. Considerableeffort was expended on improving the deep waterfording ability and for amphibious operations,swimming devices consisting of jettisonable flotationtanks were developed. However, the latter wereext remely bulky and could hardly have beentransported on shipboard where space was at apremium.

Two views of the M26 prepared for deep water fording areshown at the right and below.

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Further development of the waterproofing technique for deepwater fording is apparent in the two top photographs. Notethe overall cover used to seal around the gun shield in com-parison with the method illustrated on the opposite page. Thetelescope and coaxial machine gun ports also remain openallowing the weapons to be fired. The two large brackets fixedto each side of the hull next to the first and last road wheelsare attachment points for flotation gear. Details of the enginecompartment covers are shown in the two photographs at theright. The covers provided a watertight base for the large cool-ing air stacks. Note the modified version of the travel lock forthe 90 mm gun.Two stages in the sealing procedure for the gun shield areillustrated below. The use of sealant around the drivers'hatches and periscopes is also clearly visible.

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M26 serial number 2011 equipped with the T99 rocketlauncher at Chrysler. This was the 250th Pershing produced atDetroit Tank Arsenal and it is fitted with the T80E1 tracks.

Efforts to increase the tanks firepower led to theinstallation of the 4.5 inch multiple rocket launcherT99 consisting of two launchers, one on each side ofthe turret with a combined total of 44 rockets. Thelaunchers were traversed by rotating the turret and,by means of a connection to the gun shield, wereelevated with the 90 mm gun. The launchers weremounted on trunnions and fitted with a device thatallowed them to be jettisoned from inside the tank.The rockets could be fired individually, in salvos oftwo, or by full automatic ripple fire. With the latter,all 44 rockets could be fired in about seven seconds.

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Above: Pershing, serial number 2011, under test at AberdeenProving Ground in December 1945.Right: Closeup of the T99 rocket launcher showing the linkageto the gunshield.

Experience during the war indicated a need formore secondary armament to deal with soft targets.The standard machine gun mounts were consideredinsufficient and ways were sought to increase thesecondary firepower. Some experiments mountedmachine guns over the fenders which were fired byremote control from inside the tank. Another ap-proach replaced the commander's cupola with atwin machine gun turret. This was designated thetwin machine gun mount T121 and was designed tofit on either the M26 or M4 medium tanks. Themount was armed with either two .30 caliber or two.50 caliber machine guns and was aimed and firedfrom inside the turret. The mount was tested atAberdeen on both the Pershing and the Sherman inApril 1946 along with the fender mount guns.

Right: A comparison between the T121 mount and the stand-ard vision cupola. The extra height of the T121 was a majordisadvantage of this type of mount.Below: The T121 mount with two .50 caliber machine gunsunder test on the Pershing at Aberdeen Proving Ground. Notethe .30 caliber machine gun mounted on the right fender.

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T26E2 production pilot (above and below) at Aberdeen Proving Ground in July 1945.

THE M45 (T26E2), T26E4, AND T26E5

Because of the successful application of the 105mm howi t ze r to the M4 tank series, earlyconsideration was given to arming the T23 with thesame weapon. Following the "combat team" concept,it was desirable to use a common chassis for as manyweapons as possible. A combination mount, based onthe one used with the 76 in the T23, was designedand built for the 105 mm howitzer M4. With the shiftin interest to the T26E1, the design was reworked,incorporating a heavier gun shield, for application tothat vehicle. Mounting the howitzer, the tank wasassigned the designation T26E2. Drawings of thehowitzer mount, turret, and fighting compartmentwere released to the Fisher Tank Arsenal and Chryslerat Detroit Tank Arsenal in October 1944. Woodenmock-ups were prepared to aid in the design and thenecessary stowage rearrangement to replace the 90mm ammunition with 105 mm rounds. The gunshield was redesigned to minimize any impact loadingon the trunnions and trunnion bearings which mightresult from a hit on the shield. The first turret wasconstructed at Fisher for installation on the pilotchassis built at Detroit Tank Arsenal.

The 105 mm howitzer M4 was considerablylighter in weight than the 90 mm gun it replaced andthis was compensated by increasing the maximumthickness of the gun shield to 8 inches and the frontturret armor to 5 inches. The turret sides varied from3 to 5 inches in thickness. The new mount carried thecoaxial .30 caliber machine gun M1919A4, an M76Gtelescope, and was designated the combination mountTl 17, later standardized as the M71. Hydraulic powertraverse was provided and the mount was stabilized in

elevation which ranged from -10 to +35 degrees. Therearranged stowage allowed space for 74 rounds of105 mm ammunition. Other features of the tank wereidentical with the late production M26.

Although scheduled for completion in April1945, interest in the 105 mm howitzer as tank arma-ment had begun to drop and the pilot tank (regis-tration number 30131576) was not delivered toAberdeen until July. Originally, it was intended toproduce more tanks armed with the 105 mmhowitzer, than with the 90 mm gun. However, laterbattle experience in Europe had reversed this trendby the spring of 1945 and major emphasis was cen-tered on the high velocity gun. Both Chrysler andFisher were originally issued contracts to produce theT26E2. With the end of the war in Europe and re-duced interest in the howitzer as tank armament,Fisher's contract was cancelled and Chrysler's re-duced in numbers. Production began in July 1945 atDetroit Tank Arsenal. Production was cut backfurther at the end of the war and only 185 vehicleswere produced by the end of 1945. In the postwarperiod the tank was standardized as the medium tankM45 and some saw action in Korea.

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The T26E2 production pilot shows several modifications standardized for late production Pershings. Note the additionalpedestal for the .50 caliber machine gun in front of the commander's cupola and the exhaust muffler mounted on the rear ofthe hull.

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Two views of the T26E2 during Armored Board tests at FortKnox are shown above and at the left. Note the low positionof the coaxial machine gun compared to the 90 mm gun Persh-ings. On this tank, the .50 caliber machine gun has beenstowed, fully assembled, on the turret bustle rack. The barrelcan be seen protruding from behind the turret.

The gun mount cover is removed in the photograph at theright revealing the heavy curved gun shield. This shield wasalmost twice as thick as that on the standard Pershing M67 gunmount, reaching a maximum of eight inches. Like other lateproduction Pershings, the T26E2s were equipped with theT80E1 double pin track.

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Scale 1:48Medium Tank M45 (T26E2)

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Armament details of the M45 include the howitzer travelinglock and coaxial .30 caliber machine gun port (above right).The hull mounted drivers' periscopes have been eliminatedleaving only one periscope per driver, fitted in the hatch cover.The interior view from the loader's position (at left) shows thebreech of the 105 mm howitzer M4 and the coaxial .30 calibermachine gun.

The inside of the turret shows the gunner's station (at left) and the radio equipment stowed in the turret bustle just back ofthe loader. The AN/VRC-3 radio was used for communication with infantry units during support operations.

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The 105 mm howitzer M4 (top right) was ballistically identicalwith the standard M2A1 field artillery weapon. The breechwas rotated 90 degrees with a horizontal sliding breechblockreplacing the vertical sliding block of the artillery piece. Thesame semifixed ammunition was used for both weapons. Withthis type of ammunition, the projectile is removable from theloosely attached cartridge case, permitting the propellingcharge to be adjusted. Removal of powder increments allowedthe strength of the propellant to be set over a range from oneto seven. The most widely used 105 mm round was the highexplosive shell Ml. This shell together with the HEAT (highexplosive antitank) M67 hollow charge round is illustrated atthe right.

The 105 mm howitzer mount in the three views above and atthe right was developed for the medium tank T23. Furtherwork on this mount was discontinued when interest shifted totheT26El.

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The first experimental mounting of the 90 mm gun T15E1 in T26E1 number 1 (above and below) at Aberdeen ProvingGround. The large external equilibrator spring was completely exposed on this early installation. Note the heavy counter-weight on the turret bustle necessary to balance the long gun.

Ballistically the 90 mm gun M3 was quite similarto the German 8.8 cm KwK 36, mounted in the TigerI. Like the 90, it was developed from an antiaircraftgun, in this case the 8.8 cm Flak 18. With theappearance of the high powered German 8.8 cm KwK43 in the King Tiger or Tiger II tank and its equiva-lent Pak 43 antitank gun, the need for a higherpowered version of the 90 was apparent. To meet thisrequirement, the 90 mm gun T15 was developed andmounted on a towed carriage. The new weapon was73 calibers in length and had a much longer, highercapacity chamber. To expedite production of the firsttwo gun tubes, use was made of two forgings alreadyon hand at Watervliet Arsenal. These forgings wereslightly undersize for the T15 design and resulted in agun tube with a slightly smaller chase. These first twoguns were designated as 90 mm guns T15E1. Amuzzle velocity of 3750 ft/sec was attained with theT30E16 (APCR) type shot. The T33 shot had amuzzle velocity of 3200 ft/sec in the new gun andcould penetrate the Panther's frontal armor up to arange of 2600 yards.

The excellent armor protection of the KingTiger and Panther tanks made it increasingly desirableto mount such a high powered weapon in a tank andthe most suitable vehicle available was the Pershing,just coming into production. For test purposes, aT15E1 gun was mounted in T26E1 number 1 atAberdeen Proving Ground and proof fired. Thesetests indicated it was extremely difficult to handlethe long ammunition for the T15 gun inside acramped tank turret. The complete T33 round was 50inches in length. Stowage of the long fixed roundsalso presented a problem. To correct this, the gun wasredesigned to use two piece, separated ammunition.With this system, the projectile was loaded first andthe cartridge case was placed behind it. The cartridgecase and projectile were stored separately and thenose of the case was plugged. With its chamber re-designed for two piece ammunition, the gun was re-designated 90 mm gun T15E2.

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OCM action in March 1945 designated the tankmounting this weapon as the T26E4 and authorized alimited procurement of 1,000 in place of an equalnumber of M26 tanks. Two temporary pilots wereconverted by the Wellman Engineering Company andthese were readily identified by the externalequilibrator springs necessary to compensate for thelong heavy gun barrel. Other changes included theinstallation of a heavier elevating mechanism, turrettraveling and turret ring locks, and modification ofthe cradle to handle the heavier weapon. The turretwas balanced by welding a heavy counterweight torear of the turret bustle and the ammunition stowagewas redesigned. The first temporary pilot was shippedto Aberdeen Proving Ground on January 12, 1945and, following proof firing, was shipped overseas.This first tank was the further modified T26E1 num-ber 1 and was still equipped with the T15E1 gunusing the one piece, fixed ammunition. Its adventuresin Europe have already been described. The secondtemporary pilot T26E4 was converted from T26E3serial number 97 (registration number 30119907) andshipped to Aberdeen for test. This vehicle had theT15E2 gun with separated ammunition.

The second temporary pilot T26E4, serial number 97, undertest at Aberdeen Proving Ground. The double external equilib-rator springs are now enclosed in protective cylinders. The firsttemporary pilot was fitted with this same type of equilibratorprior to its shipment to Europe. Since the second pilot wasconverted from a production T26E3, the turret was fitted withthe small oval loader's hatch.

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The design for an internal hydropneumatic equi-librator was completed and incorporated in the pro-duction vehicles. The new stowage arrangements pro-vided space for 54 rounds of separated 90 mm ammu-nition. Except for the changes necessary to handlethe heavier gun, the T119 combination gun mountwas identical with that on the M26. The same coaxial.30 caliber machine gun was carried, but an M71E4telescope was installed for use with the higher velo-city gun. The turret was equipped with a hydraulicpower traverse system. Elevation ranged from -10 to+20 degrees and no stabilizer was fitted. With the endof the war in Europe, the number of T26E4s wasreduced to 25, all produced at the Fisher TankArsenal. Tests at Aberdeen Proving Ground ranthrough January 1947. Because of the loading pro-blems associated with the two piece ammunition, in-terest in this type of weapon rapidly faded with thecessation of hostilities and the appearance of betterdesigned one piece ammunition for tank guns. Someof the T26E4s were eventually used as target vehicles.

The T26E4 production pilot converted from T26E3 serialnumber 84. The hydropneumatic equilibrator has been in-stalled eliminating the external springs.

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These views of the production pilot (above) show the new traveling lock fitted for the long barreled high velocity gun.

A production T26E4 was shipped to Fort Knox for tests by the Armored Board. This tank (below) was registration number30128151, serial number 1405. The necessity for the new traveling lock for the gun is apparent (below left). Unless the gunwas carried in an elevated position, the long barrel might strike the ground when crossing rough terrain. The extremes ofelevation and depression obtainable with this mount are shown at the lower right. Like other late production Pershings, theT26E4 is equipped with the T80E1 double pin track and the lugs for the power unit hoisting device have been omitted fromthe turret. The drivers' auxiliary periscopes have also been eliminated.

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Scale 1:48

Medium Tank T26E4

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Even with two piece ammunition, the extreme length of thecartridge case caused loading problems. The interferencebetween the case and the turret ring shown above occurredwhen the gun was in an elevated position.

A T26E4 operating in wooded terrain at Aberdeen ProvingGround. Maneuvering in such areas required extreme care withthe long barreled cannon. One mistake would wrap it around atree. Note the twin .50 caliber antiaircraft machine guns onthis tank.

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The 90 mm gun T15E2 is shown here with two types of itsseparated ammunition.

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The T26E5 at Aberdeen Proving Ground (above and below) in July 1945. This tank was registration number 30150824 withserial number 10007. Compare the massive turret and front hull castings with the standard Pershing.

The successful combat use of the heavilyarmored assault tank M4A3E2 pointed out thedesirability of an equivalent version of the M26.Preliminary studies produced a design with a slopedfront hull having a maximum actual thickness of 4 3/4inches. A new turret casting provided an 8 inchthickness. This was intended to give a frontal armorbasis of 8 inches for the entire vehicle. Othernecessary changes were increased equilibratorcapacity to offset the gun shield weight and a lowergear reduction to handle the overall increased vehicleweight. Five inch extended end connectors were usedon the T80E1 tracks to reduce the ground pressure.

OCM action on January 18, 1945 recommendedthe procurement of ten tanks, T26E3, with thesemodifications and that the modified vehicle bedesignated T26E5. This was approved on February 8,1945. However, on March 29 the OrdnanceCommittee recommended additional increases in thefrontal armor and changed the quantity of tanks to27. Under the new specification, the hull castingwould have a thickness of 6 inches at 46 degrees onthe upper slope and 4 inches at 54 degrees on thelower slope. The turret casting had a thickness of 7 1/2inches on the front, 3 1/2 inches on the sides and 5inches on the rear to balance the heavy gun shield.The new gun shield casting had an actual thickness of11 inches at 0 degrees. This heavy shield requiredincreased equilibrator capacity plus a 60 poundweight on the recoil guard to balance the gun.Additional thickness was added to the front turretring splash guard to protect the thin machined surfaceof the turret adjacent to the ring. It was necessary todecrease the width in the rear portion of the hullescape doors to provide clearance between the doorsand the turret. With these changes, the vehicle weightincreased to 102,300 pounds, but by use of the 23inch T80E1 track and 5 inch extended endconnectors, the unit ground pressure was held to 11.9pounds per square inch. The weight increase alsorequired a change in the final drive gear ratio from1:3.95 to 1:4.47.

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Production started at Chrysler in June 1945 andthe first pilot vehicle (registration number 30150824)was delivered to Aberdeen Proving Ground in July.The tests at Aberdeen indicated that the T26E5compared favorably in performance with the M26.However, it was necessary to drastically reduce speedover rough terrain to avoid damaging the suspensionsystem. With the end of the war, no additionalvehicles were produced and the 27 T26E5s were usedfor test purposes.

To lower the ground pressure, the track width was increasedby replacing the standard end connectors on the double pintracks with the 5 inch "duckbill" extended connectors. Asshown below, external stowage arrangements were the same asthe standard late production Pershing.

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Scale 1:48Medium Tank T26E5

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The third production T26E5, serial number 10009, during testsat Fort Knox. The gun mount cover has been removed and themassive gun shield is exposed. Note an almost square edge hasreplaced the curved lower part of the standard shield. This wasan attempt to minimize the shot trap caused by the lower edgeof the shield in much the same way as the Germans modifiedthe late production Panther G. Further details of the turretand shield are shown in the bottom photograph. The numberschalked on the turret indicate the actual thickness of the cast-ing at that point. Note that the extended end connectors havebeen removed from the tracks and standard width sandshieldsfitted. This was necessary to reduce the overall width for trans-portation.

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The second pilot M26E1 (above and below) during tests at Aberdeen Proving Ground.

The M26E1, M26E2, AND M26A1

After the difficulties with separated ammunitionin the T26E4, the 90 mm gun T54 was developed toprovide a weapon with a fixed, one piece roundsuitable for use inside a tank turret. The ballisticperformance and chamber capacity of the 90 mm gunT15E2 were retained, but the cartridge case wasredesigned with shorter and fatter dimensions. Thisprovided a complete round of convenient size tohandle and load inside the tank turret. The overalllength of the T54 was less than the T15E2, due to itsshorter chamber and the muzzle brake was reduced toa single baffle model by machining off the frontbaffle from a standard 90 mm brake. Except for themuzzle brake, the gun was quite similar in appearanceand performance to the German 8.8 cm KwK 43,which armed the King Tiger.

In June 1945, the Ordnance Committeeapproved the development of two M26 pilots mount-ing the new gun. These pilots were assigned the de-signation M26E1. To reduce the congestion inside theturret, a concentric recoil mechanism was developedfor use with the T54. Except for the new recoilsystem, the rest of the gun mount and turret com-ponents were basically the same as on the T26E4.The coaxial .30 gun in the T26E4 was replaced by a.50 caliber machine gun HB M2 and the new mountwas designated as the 90 mm combination gun mountT126. It also carried an M83C direct sight telescopefor the gunner. Ammunition stowage was rearrangedto carry 41 of the new stubby fixed rounds.Thirty-six of these were stowed in the floor bins andfive were in the ready rack on the loader's side of theturret.

The two tanks were converted by the MartensFerry Division of Blaw Knox Company and thesecond pilot was shipped to Aberdeen ProvingGround, while the first was retained at DetroitArsenal.

The tests at Aberdeen, from February 1947 toJanuary 1949, indicated that the accuracy of firefrom the 90 mm gun T54 and the reliability of itsconcentric recoil mechanism were excellent. Theweapon was considered superior to all other U.S. tankguns tested up to that time.

The limited funds available during the imme-diate postwar period drastically reduced new vehicledevelopment. Following the precedent set prior toWorld War II, effort was concentrated on developingcomponents. This method had proven successfulduring the 1930's and had resulted in a suitable lineof engine, power train, and suspension componentsbeing ready when the need came in 1940. Followingthis approach, studies were made on improvements intransmission and power plant design.

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The second pilot was converted from M26 serial number 837produced by Fisher and is still equipped with the T81 singlepin track. The gun travel lock was modified similar to that forthe T26E4 in order to hold the long barrel at a higher eleva-tion. The attachment points for the original travel lock are stillin place. The long barrel of the .50 caliber coaxial machine guncan be seen protruding from the gun shield.

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Scale 1:48

Medium Tank M26E1

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The stubby round for the 90 mm gun T54 is compared (above left) with the standard 90 mm, 76 mm, 75 mm, and 37 mmtank ammunition. Stowage arrangements are shown below in the ready rack (bottom left) and floor bins (bottom right) asviewed from the loader's hatch. The T54 gun in the T126 combination mount (above right) saved considerable space in theturret due to the compact concentric recoil mechanism. The coaxial machine gun and telescopic sight have not been fitted inthis photograph.

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Medium tank M26E2 during the test program at AberdeenProving Ground in May 1948. In addition to the rear hullmodifications, a major recognition point is provided by thefender mounted mufflers connected to the transverse exhaustpipes.

In 1948, a modernization program was begun toproduce an, improved version of the medium tankM26. The modernized vehicle was to have a new 810horsepower air cooled tank engine in combinationwith a cross-drive transmission.

Both the engine and transmission were productsof projects started during the war and continued intothe postwar period under the componentdevelopment program. Together they provided apower unit of 810 horsepower which was over fiveinches shorter than the 500 horsepower package itreplaced. This remarkable achievement was due to theGeneral Motors cross-drive transmission. TheContinental AV-1790-3 air-cooled engine was 67.25inches in length compared to 45.35 inches for theFord GAP in the M26, but the cross-drivetransmission only took up 29.5 inches in lengthcompared to 56 inches for the transmission anddifferential it replaced.

As its name indicated, the cross-drive wasmounted in the transverse direction at the rear of theengine compartment and it combined the functionsof the transmission, steering control, and vehiclebrakes. As a transmission, it incorporated twohydraulically selected gear ranges driving through atorque converter. A portion of the engine power wastransmitted through a mechanical path by-passing thetorque converter. This mechanical power, in additionto the power transmitted hydraulically, was appliedequally to both output shafts except that in steering,all of the mechanical power was applied to one sideto provide the necessary speed difference between thetracks. Braking was accomplished by built-in disctype brakes actuated mechanically from a pedal inthe drivers compartment. Steering and shifting wereby means of a "joy-stick" type control lever, greatlyreducing driver fatigue. Detroit Arsenal installed thenew power package in a modified M26 and thevehicle was redesignated as the medium tank M26E2.In May 1948 the M26E2 (registration number3012420) was shipped to Aberdeen Proving Ground

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Scale 1:48

Medium Tank M26E2

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for test. Like most experimental tanks, it sufferednumerous problems, mostly associated with thereliability of the early models of the new power traincomponents. However, the speed and handlingcharacteristics were far superior to the earlier M26and the test results were incorporated in the newermedium tank T40, later standardized as the M46.

Originally, the M26E2 was intended to carry thehigh velocity 90 mm gun T54 tested in the M26E1, aswell as general improvements in the fire controlsystem. However, the high velocity gun was droppedand efforts were made to improve the standard 90mm gun M3. A bore evacuator was fitted around thetube just back of the muzzle brake to eliminatepowder fumes from the turret when firing. Themuzzle brake was redesigned to a lighter weight,single baffle version, since its major function was todirect the blast sideways reducing the obscurationfrom dust kicked up during firing. With thesechanges, the gun was installed first on the mediumtank T40 and later standardized on the M46 as the 90mm gun M3A1 in combination mount M73.

When supplies of the new M3A1 gun becameavailable, it was possible to refit some of the standardM26s with the new weapon. For the M3A1, the M67mount was fitted with a lighter equilibrator spring,because of the smaller torque imposed by the lightermuzzle brake. The gun travel lock was also modifiedand the designation changed to the combinationmount M67A1. Some of these vehicles were alsofitted with an elevation stabilizer for the gun. Boththe M26A1 and the M46 were destined to servealongside the standard Pershing in Korea.

The Pershing's offspring, the medium tank T40. Developedfrom the M26E2, it was later standardized as the M46 andbecame the first of a series of tanks to carry the name Patton.The fender mounted mufflers are still apparent and the 90 mmgun has been fitted with a bore evacuator. Note that themuzzle brake has been modified to a single baffle model quitesimilar to that on the M26E1.

Details of the 90 mm gun M3A1 are shown above and below.This is the weapon that equipped both the M46 and theM26A1.

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An example of the modernized Pershing, the M26A1, on dis-play (above) today in Berlin. It was rescued from the junk pileand restored by the 40th Armor. This tank, serial number 394,originally had the registration number 30127140 and wasproduced by Fisher in March, 1945. Markings uncovered dur-ing restoration, indicated it was used by at least two NATOarmies following its U.S. service. Photographs taken at earlierstages of the restoration process are shown at left and below.

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An artist's drawing showing the 90 mm antiaircraft gun Ml mounted on the chassis of the T23 medium tank.

VEHICLES BASED ON THE M26

Experience during the early war years under-lined the advantage of using the same basic chassis foras many vehicles as possible. A standard set of com-ponents greatly reduced the spare parts inventory andsimplified maintenance procedures. This lesson gavebirth to the "combat team" concept. The "combatteam" was a group of vehicles such as artillery motorcarriages, cargo carriers, tank recovery vehicles, andsimilar equipment, all based on a particular tankchassis and using as many standard parts as possible.Following this idea, a variety of vehicles weredeveloped using components from the T20 seriestanks.

In early 1943, a design study called for themounting of the 90 mm antiaircraft gun on themedium tank T23 chassis and in March such an

installation was demonstrated to General Devers,General Barr, and other officers. These tests proveduseful in the design of the T25 and T26 tanks later inthe year.

Following the success of the 155 mm gun motorcarriage M12, a lightweight chassis using the engineand power train of the medium tank T23 was pro-posed as a new artillery motor carriage, designed tocarry either the 155 mm gun M1 or the 8 inchhowitzer M1. The vehicles were designated re-spectively, 155 mm gun motor carriage T79 and the 8inch howitzer motor carriage T80. The cargo carrierT25 based on the same chassis was proposed as anaccompanying vehicle. Objections by the ArmyGround Forces to the use of the electric drive re-sulted in the rejection of all three vehicles.

A model of the T23 chassis fitted with the 90 mm antiaircraft gun.

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In April 1944, the Army Ground Forcesapproved the development of the 8 inch howitzermotor carriage T84 based on the medium tank T26E1chassis. The f irs t pilot (registration number40215108) was completed at the Chrysler Engineer-ing Division Tank Laboratory and shipped to Aber-deen Proving Ground, arriving in February 1945.Although it used many components of the T26E3,they were drastically rearranged. A new hull was con-structed with a maximum armor thickness of oneinch and the upper front plate was sloped at 64degrees from the vertical. Separate, four block, visioncupolas for the driver and assistant driver replaced thecustomary periscopes. The other six crew membersrode at the rear of the carriage. The standard T26E3power train was rotated 180 degrees placing thedifferential at the front of the vehicle, the trans-mission between the drivers, and the Ford GAFengine just behind the driving compartment. TheT26E3 suspension, fitted with the 24 inch T81 track,was used with the drive sprockets moved up to thefront and the idler and track compensating armmounted at the rear. By converting to a front drivevehicle, maximum free space was obtained at the rearfor mounting the 8 inch howitzer M l. Six emergencyrounds of 8 inch ammunition were stowed below thefloor at the rear of the carriage.

When received at Aberdeen, the upper frontarmor was a solid rolled plate carrying two rows ofs tuds for moun t ing spare track links. Laterphotographs, taken in April 1945, show that a largeaccess hole was cut in the plate and closed by abolted removeable cover. No doubt the change wasmade to permit servicing of the differential withoutremoving the power train from the hull.

The sketch and the photographs show the 8 inch howitzermotor carriage T84 as it was received at Aberdeen ProvingGround.

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The T84 was a front drive vehicle with the sprocket at thefront and the adjustable idler at the rear (above). As receivedat Aberdeen, the front armor was a solid plate (left) fittedwith studs for mounting track links. Compare with the topview (below) showing a removable cover bolted on the frontplate. The arrangement of the external stowage is also clearlyshown in this photograph.

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The 8 inch howitzer motor carriage T84 during firing tests at Aberdeen in April 1945. The shell is being rammed in the leftphotograph and at the right, the howitzer has just been fired and the tube is in full recoil.

Crew seating arrangement on the motor carriage (right). Sixmen were carried in the positions shown. The two remainingcrew members rode in the drivers' positions in the front hull.

Stowage space for six emergency rounds of 8 inch ammunition was provided in the hull floor behind the howitzer mount(bottom left). The other photograph (bottom right) shows the breech mechanism of the 8 inch howitzer Ml with the block inthe closed position. The handwheels for moving the howitzer in azimuth and elevation as well as the sighting equipment canbe seen on both sides of the weapon.

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Cargo carrier T31 during the postwar period at Aberdeen Proving Ground. The chassis was identical to that of the 8 inchhowitzer motor carriage T84 and also was fitted with an access hole in the front armor plate. Note that a steel strip has beenwelded around the hole to prevent bullet splash from entering under the hole cover.

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The cargo carrier T31, based on the same chassiscomponents, was designed as the accompanyingvehicle. The carrier used the same front drive arrange-ment, suspension, and hull construction as the T84,with one inch armor protection on the front andlower sides. The howitzer mount was replaced by alarge open top stowage compartment constructed ofhalf inch armor plate. Space was available for 60 com-plete rounds of 8 inch howitzer ammunition with aspecial crane for handling the heavy shells. Four ofthe six man crew rode in the stowage compartment.A .50 caliber machine gun on a ring mount over theassistant driver's hatch provided antiaircraft defense.One pilot T31 was completed by the ChryslerEngineering Division.

The views above and below show the cargo carrier T31 after completion at Chrysler on April 9, 1945. The upper photographshows the bad weather hoods erected over the drivers' hatches.

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The top views (above) show the stowage compartment with and without the canvas cover in place. The racks for thepropellant charges are in the center of the compartment. Shell stowage is shown in the left stowage compartment (below left)and the right shell locking tray (below right).

The individual weapons for the crew were located in the small arms stowage on the front bulkhead (below left). Five crewmembers were issued carbines while the sixth received a .30 caliber rifle M1903A3. The latter was no doubt for use with theantitank rifle grenades shown in right side stowage compartment (below right).

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The 240 mm howitzer motor carriage T92 at Aberdeen Proving Ground on 7 July 1945 is shown in the top and bottomphotographs. A single post traveling lock was used to minimize the blocking of the driver's vision. This was considered animprovement over the T84.

The effective use of the 155 mm GMC M12 inEurope had encouraged Ordnance to consider thedevelopment of even heavier self-propelled artillery.In January 1945, self-propelled mounts were pro-posed for the 8 inch gun Ml and the 240 mmhowitzer M1. T26E3 components were used for theengine, power train, and suspension with a lighterweight chassis and the two weapons were designated,the 240 mm howitzer motor carriage T92 and the 8inch gun motor carriage T93. The chassis were identi-cal in both cases and the weapons could be inter-changed. Following the design experience with the 8inch howitzer motor carriage T84, a lightweight,although longer, hull was constructed with a maxi-mum armor thickness of one inch. Two cupolas, with

The T92 was a snug fit on a flatcar even without extended endconnectors on the track.

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three vision blocks each, were provided for thedrivers. Unlike the T84, the cupolas were mounted inthe sloped front armor, the angle of which was in-creased to 72 degrees from the vertical. The re-maining six members of the eight man crew rode ateach side of the gun behind the mount. Noammunition was stowed on either the T92 or T93.Because of the larger and heavier weapons, the chassiswas lengthened, requiring an additional roadwheelover the standard T26E3 suspension. Double pinT80E1 tracks were installed and were often fittedwith five inch extended end connectors to lower theground pressure. The power train was reversed, as onthe T84, converting the carriage to a front drivevehicle. The cargo carrier T31, with stowage re-arranged to handle the heavier ammunition, was in-tended to be the accompanying vehicle for bothweapons.

Original intentions were to ship the pilotcarriages to the Pacific Theater for combat testing. Itwas believed that their powerful weapons would be ofgreat value in reducing the Japanese bunkers and cavedefenses. However, the atomic bomb brought aboutthe surrender of Japan before the plan was put intoeffect.

Five pilot T92s were constructed, but thelimited procurement order issued in March 1945 wascancelled by the end of hostilities. Two pilot T93swere built and under test at the end of the war. Oncethe war was over, interest in the T92 and T93declined. Tests at Aberdeen revealed the need for amore powerful engine for such heavy vehicles. It wasrecommended that future heavy self-propelledar t i l lery be designed around the power traincomponents of the new heavy tanks T29, T30, andT32 then under test.

Below: Ready for loading, the 8 inch gun is in firing positionwith the loading tray in place.

The 8 inch gun motor carriage T93 was identical to the T92except that the howitzer was replaced by the 8 inch gun Ml.Note the extreme overhang in the travel position above, whenfitted with the long barreled cannon. The 8 inch gun in firingposition at maximum elevation is shown below.

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This sequence of photographs from side to top clearly shows the general arrangement and external stowage of the T92.Except for the main weapon, the T93 was identical.

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Front and rear views of the T92 are shown above. Note theaccess hole and cover plate on the front armor similar to thatontheT84andT31.Details of the spade are seen in the view at the left. In thisphotograph the spade is raised only about halfway to thetravel position.

The T92 climbing over the tires onto a tank transporter. Note that the 5 inch extended end connectors have been fitted.

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The 240 mm howitzer during firing at Fort Bragg, North Carolina. According to the markings on the vehicle, this was actuallythe 8 inch gun motor carriage T93 number 1 with the gun replaced by a howitzer.

The T92 at speed during field tests at Aberdeen. The 5 inch end connectors are fitted to reduce the ground pressure.

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Construction details which apply equally to the T92 or theT93. The arrangement of the seven road wheels with shockabsorbers mounted on the first two and last two is clearlyvisible (above). Raising the number of road wheels to sevenalso required the addition of a track return roller giving a totalof six per side. The gun mount for the 240 mm howitzer orthe 8 inch gun is seen at the left.A rear view of the chassis (bottom left) shows its appearancebefore fitting the gun mount.With the top plate carrying the vision cupolas removed, theentire drivers' compartment is exposed (bottom right). Similarto the tanks, the instrument panel is mounted in the centerand duplicate controls are provided for the driver and assistantdriver.

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170

Tank recovery vehicle T12 with the boom extended over the front (above left) and left side (above and below) of the vehicle.The front spade is lowered to brace the vehicle when lifting a heavy load over the front.

In 1944, development was started on a tankretriever based on the Pershing chassis. The newdesign was designated the tank recovery vehicle T12and was intended to be a service unit for handlingheavy turrets, power units, and other components, inaddition to its function of removing tanks from thebattle area. The standard turret of the M26 wasreplaced by a lighter turret 1-1/4 inches thick, fittedwith a telescopic boom and winch. The turret andboom could be traversed 360 degrees and operated inany position. With the boom at the rear in travelingposition, its lifting capacity was 25 tons. Twenty tonscould be lifted with the boom at extreme extension,but with the load not more than eight feet, fourinches from the vehicle. The boom could be raised orlowered with a load not exceeding 12 tons and theturret could be traversed with a maximum load ofeight tons. Two winches, one for the boom and onefor line operations, were mounted in the bulge at therear of the turret. The chassis, hull armor plate, andcontrols were the same as the M26 tank. T80E1double pin tracks with five inch extended endconnectors gave a total track width of 28 inches.Normally, a crew of six was required. The .30 calibermachine gun was retained in the bow mount and a.50 caliber antiaircraft machine gun was ring mountedat the right on top of the turret. A vision cupola wasprovided for the vehicle commander on the left sideof the turret roof.

Although cancelled by the end of the war, adesign was proposed for the mine resistant vehicleT15E3 based on the M26 tank. This vehicle was to befitted with heavy belly armor and mine resistanttracks to permit greater safety when used as a primemover for mechanical mine exploding devices.

The top view (at right) shows the boom in the traveling posi-tion over the rear. The open, ring type, machine gun mountand the commander's cupola are visible on top of the turret.

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The interior arrangement is shown in the sectional view above. Details of the spades in the raised and lowered positions can beseen below.

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Scale 1:48

Tank Recovery Vehicle T12

Unlike the other drawings in this book, these views of the T12were reproduced directly from the original Arsenal drawings.An error is noted in the rear view. The tank is shown equippedwith T81 single pin tracks fitted with extended end con-nectors, an obviously impossible condition. No doubt a war-time draftsman tried to save some time by tracing the tracksfrom a Pershing drawing and adding the "duckbill" con-nectors. For a proper view of the T80E1 double pin track withthe extended end connectors, see the drawing of the T26E5 onpage 148.

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PART III

FINAL SERVICE

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The Soviet built T34/85 medium tank.

KOREA

Before dawn on Sunday, June 25, 1950, units ofthe North Korea People's Army (NKPA), attackedsouthward across the 38th parallel. The attack forcenumbered about 90,000 men and included seveninfantry divisions and one armored brigade. The in-vasion was without warning and achieved completesurprise, although many ominous signs during pre-vious weeks had indicated the possibility of animpending attack.

On June 8, 1950, newspapers in the northerncapital of P'yongyang published a manifesto callingfor the election of a national parliament from bothnorth and south to meet in Seoul on August 15, thefifth anniversary of Korea's liberation from Japan.Apparently the northern leadership believed that a"Blitzkrieg" invasion would be able to destroy theRepublic of Korea (ROK) Army in the south in asingle rapid thrust. The elections could then be heldunder northern control in the occupied area and asingle communist government established in Seoul bythe middle of August. To achieve such a rapid andcomplete victory, a striking force of great power andmobility was required. This was provided by the 150Soviet T34/85 tanks available to the NKPA. The105th Armored Brigade was equipped with 120 T34sand the remaining 30 were assigned to the 7th In-fantry Division at Inje in east central Korea just priorto the attack. The tanks of the 105th led the drive tothe Han river and, after the capture of Seoul, the unitwas redesignated the 105th Armored Division.

The T34 which performed so effectively in theseoperations was the same vehicle widely used by theSoviet Army during the latter part of World War II.The combination of the 85 mm gun and the wellarmored, highly mobile chassis was a formidablefighting vehicle, difficult to defeat even with the bestof antitank weapons. In June 1950, such weaponswere not available to the South Korean Army. Theyhad only the early World War II 37 mm antitank gunsand their artillery was limited to a few U.S. 105mmM3 howitzers. This was a short barreled version of thestandard M2A1 weapon, with a lower muzzle velo-city. Little or no HEAT ammunition was provided forantitank defense. The infantry units were equippedwith the obsolete 2.36 inch "Bazooka" rocketlauncher left over from World War II and itsammunition was old and unreliable.

In June 1950, the South Korean Army had notanks and the U.S. forces in the Far East were notmuch better off. Each of the four U.S. divisions onoccupation duty in Japan was assigned a tankbattalion, but each had only one company (A)organized and equipped. Even though some weredesignated as heavy tank battalions, the onlyequipment provided was the M24 light tank. Thisvehicle was satisfactory for occupation duty andminimized the damage to light bridges and roads inJapan.

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A U.S. M24 light tank moves through a Korean village enroute to the front on July 8, 1950.

Despite their lack of suitable weapons, theSouth Koreans fiercely resisted the initial advance ofthe T34s. Antitank weapons were improvised usingsatchel charges and hand grenades. South Koreansoldiers even climbed on top of some tanks trying topry open a hatch to throw in a hand grenade. A fewT34s were destroyed, but the usual result was thatthe attackers were killed and the tanks rolled onunharmed. The appearance of invincibility had its

effect on morale and it rapidly became difficult tofind volunteers willing to attack the tanks.

With the entry of American ground troops intoaction, the M24 light tanks were moved from Japanto Korea. They were first committed to battle July10, 1950 near Chonui. It was rapidly apparent thatthe M24, although a good reconnaissance vehicle, wasno match for the T34 and two were lost during theafternoon of the 10th.

Dug in to protect its light armor, an M24 awaits the appearance of the enemy, July 9, 1950.

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The M24 light tanks engage the enemy near Chonui on July 10, 1950.

The original Signal Corps caption indicates the M24 shown inthe two views at the right was the first U.S. tank in action inKorea on July 10, 1950. The crew is shown cleaning up thetank, nicknamed "Rebels Roost", after returning from thefront.

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One of Lieutenant Fowler's Pershings test firing its guns near Taegu on July 22, 1950, six days before moving to Chinju.

Immediately after the outbreak of war, theOrdnance stores in Japan were ransacked to provideall available weapons to the forces ordered to Korea.On June 28, three Pershing tanks were located at theTokyo Ordnance Depot. All three were in very poorcondition requiring major repair. This work beganimmediately and was completed on July 13th. Thetanks, manned by 14 enlisted men under thecommand of 1st Lieutenant Samuel R. Fowler,arrived at Pusan on July 16. Lieutenant Fowler andhis crews had been trained on the M24 light tank sothey immediately began to zero their guns andfamiliarize themsleves with the heavier M26. It soonbecame obvious that the rebuilt engines left a lot tobe desired. The standard fan belts had not beenavailable in Japan and the substitutes stretched after ashort period of operation allowing the fan to stop andthe engine to overheat. New belts were requested, buthad not arrived when the three tanks were shipped byrail to Chinju arriving early in the morning of July 28.As the only medium tanks in Korea, they had to beused to try and stop the NKPA drive toward Pusanfrom the southwest. Fowler and his crews, stillawaiting their fan belts, remained with the tanks nearthe rail depot south of the Nam River until themorning of July 31, when enemy troops enteredChinju. Knowing his tanks would not withstand along road march, Fowler telephoned Masan and wastold that railway flatcars were on their way to Chinjuto evacuate the Pershings. He then decided to wait,

even though the infantry was pulling back fromChinju. About 1300 hours, an enemy patrol ofplatoon strength approached the rail station and wastaken under fire by the three tanks. The .30 and .50caliber machine guns wiped out the enemy force, butL ieu t enan t Fowler was wounded during theexchange. His crew placed him in his tank and, asother enemy troops were in the vicinity, the threePershings moved eastward along the road towardMasan. After about two miles, they were halted by ablown bridge and dismounted to proceed on foot. Alitter was being prepared for Fowler when an enemyambush opened fire, forcing some of the men to seekshelter under the bridge. Master Sergeant BryantShrader was still inside one of the tanks and hereturned the fire and maneuvered the Pershing to pickup six other men through the bottom escape hatch.Unable to reach the men under the bridge, he droveback down the road to Chinju, stopping at the NamRiver. Here the overheated engine stalled and wouldnot start again and the seven men abandoned thetank. Hiding from enemy troops, Shrader and his menmanaged to work their way back to the Americanlines at Masan, but Lieutenant Fowler and the menleft at the bridge were killed or captured. Eight menand the only three medium tanks in Korea were lostmainly through the lack of such insignificantcomponents as fan belts. It would be difficult toprovide a better modern example of the loss of abattle "for the want of a horseshoe nail".

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Two additional views of Lieutenant Fowler's Pershings while zeroing their guns at Taegu. Since the crews had trained on theM24 light tanks, they were forced to learn the operation of the Pershing on a crash basis.

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A Pershing on the road to Sach-on in action against a North Korean thrust in the Masan-Chinju area on August 10, 1950.

The key role played by the Soviet built tanksmade it essential that U.S. medium tanks swiftly betransferred to Korea. The Army notified GeneralMacArthur July 10th that it planned to ship threebattalions of medium tanks directly to the Far East asthe quickest means of getting these vehicles withtrained crews into action. The battalions selected

Troops of the 1st Cavalry Division are introduced to thenewly arrived Pershing before returning to the front on August10, 1950.

were the 6th equipped with M46s, the 70th withM26s and M4A3s, and the 73rd equipped with theM26. So once again, the Pershing and the Shermanwent to war, unloading at Pusan, Korea on August8th.

While arrangements were being made to ship thebattalions from the United States, Eighth Armyactivated the 8072nd Medium Tank Battalion inJapan. This unit was equipped with World War IIShermans salvaged from the Pacific islands andrepaired in Japan. Company A landed at Pusan onJuly 31st followed by the remainder of the battalionon August 4th. Three days later the unit wasredesignated as the 89th Tank Battalion.

The new battalions were immediately deployedto strengthen the defense of the perimeter protectingPusan. The 6th was moved to the Taegu area as partof the Eighth Army reserve, while the 70th was sentto support the 1st Cavalry Division. The 73rd wassplit up with A Company moving to Ulsan, BCompany going to the Kyongju and Kigye area, and CCompany reinforcing the 27th Infantry north ofTaegu in the region soon to be known as the"Bowling Alley". Additional reinforcements,including the 72nd Tank Battalion and the 1st MarineTank Battalion, also arrived bringing the tankstrength in the Pusan perimeter to over 500 by lateAugust. Except for the 6th equipped with M46P a t t o n s , the medium tanks consisted ofapproximately equal numbers of Pershings andShermans.

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Above: Pershings assigned to the 89th Tank Battalion firing onNorth Korean positions in the area of the U.S. 29th InfantryRegiment on August 25, 1950. The earth ramps were used toincrease the elevation and obtain the maximum range with the90.Right: Four M26s firing on a North Korean observation postacross the Naktong River during the fight for the Pusan perim-eter.Below: M26 from C Company, 72nd Tank Battalion in actionalong the Naktong River line on August 31st. In all of thesephotographs the tanks are being used as mobile artillery.

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The first encounter between the Pershing andthe Soviet T34 occurred just before dark on August17th during the first battle of the Naktong Bulge. Thelatter name was given to the loop of the Naktongriver just west of Yongsan, where elements of theNor th Korean 4th Division had crossed andpenetrated several miles east of the river. The U.S.24th Infantry Division, including the 1st MarineProvisional Brigade, counterattacked to destroy theenemy forces east of the Naktong. On the evening ofthe 17th, troops of the 1st Battalion, 5th Marineswere digging in after taking hill 102. This positionoverlooked the road crossing the pass betweenCloverleaf hill on the north and Obong-ni ridge to thesouth. It was along this road that the marinesobserved three T34s, followed later by a fourth,moving eastward toward the pass. Bazooka andrecoilless rifle teams were positioned to ambush theenemy tanks and three Pershings were called forwardto positions covering the eastern end of the pass. Asthe first T34 rounded a bend in the road it was hit byboth recoilless rifle and bazooka fire which stoppedthe vehicle, but did not silence its guns. The firstPershing now took a hand, setting it on fire with asingle 90 mm round. Small arms fire killed one crewmember who attempted to escape. The bazookateams accounted for the "second T34 the moment itcame into sight and as the third made its appearance,two Pershings destroyed it with 90 mm fire. Thefourth T34 had dropped well behind the others andwas destroyed by air action.

Above: The Marine Corps Pershing shown here on August 17,1950 is in the area where the first action occurred with theSoviet T34. Note the empty 90 mm cartridge cases along theside of the road.Below: Another Marine Corps M26 photographed in the samearea two days earlier while supporting 1st Cavalry Divisiontroops on August 15th.

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Above: Another Marine Corps M26 near Yongsan. Note that all of these Marine Corps tanks are still equipped with theoriginal T81 single pin tracks.Below: A Pershing from Company C, 73rd Tank Battalion moves up to support the 27th Infantry in the Taegu-Waegwansector on August 20, 1950.

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The "Bowling Alley" looking north toward enemy territory on August 21,1950. A Soviet built SU-76 self-propelled gun hasbeen destroyed on the road and U.S. artillery fire can be seen falling on the enemy positions up the valley.

Following the fight on August 17th, thePershings were frequently in action against the enemyarmor. On the following day the scene shifted to theTaegu front further north. Here the 27th Infantryattacked along the Taegu-Sangju road to relieve en-emy pressure on Taegu. About two miles north ofTabu-dong, enemy resistance held up the advance ofthe ROK units in the hills on both flanks of theAmerican force. The 27th then halted and formed aperimeter across the road, just north of the village ofSoi-ri. The Pershings of Company C, 73rd Tank Bat-talion were in support, with one platoon in the frontlines and four more tanks in reserve just back of theline. That evening, August 18th, they fought off thefirst of seven NKPA night attacks which were to con-tinue through August 25th. Every night, the enemyattacked south.with infantry, tanks, and self-propelled guns following the straight section of roadbisecting the American positions. Apparently duringthe wild action on the night of August 21st, this areawas nicknamed the "Bowling Alley" by men of FCompany, 27th Infantry. On this night, the enemyT34s were firing straight up the road trying to knockout the Pershings in the U.S. positions. The tracers ofthe armor piercing projectiles streaking up the roadand the thunder of gunfire rolling back from the hillson either side combined to give the impression of agigantic bowling alley.

Enemy attacks continued through the night ofAugust 24th, by which time confirmed enemy lossesincluded 13 T34 tanks and 5 self-propelled guns. U.S.troops were relieved on the night of August 25th byROK forces.

A Pershing nicknamed "Pat" from C Company, 73rd TankBattalion loads ammunition in the "Bowling Alley" on August21st.

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Pershings move between three T34s destroyed in front of theU.S. positions. One T34 is still carrying its jettisonable fueltanks. These photographs taken on August 24th show thetypical cluttered appearance of the tanks in action with allsorts of items stowed in a non-regulation manner. In thebottom photograph, the Pershing is firing at a group of NorthKoreans laying a mine field further up the valley. The muzzleblast kicks up the dirt in front of the tank.

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Above: An M26 bypasses a destroyed bridge near Tabu-dong.Below: Another Pershing in action in the same area. Both photographs were dated August 24,1950.

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Pershings of the 73rd Tank Battalion move into position onAugust 27, 1950. The tanks in these views were marked with agirl's name on the front and sides. The top tank also has thecrew member's name painted by his station.In the bottom photograph, the air from the engine coolingfans causes the aircraft recognition panel to billow above therear deck.

After the early encounters, many other actionsoccurred between the Pershing and the T34, but themajor tank work was in infantry support. Like theGerman Tiger six years earlier, the Pershing had nodifficulty in dealing with the T34 on a tank for tankbasis. The 90 mm gun could easily destroy the Sovietbuilt tanks at all normal combat ranges. However, thehigh power to weight ratio and wide tracks of theT34 gave it superior mobility, particularly in roughcountry. The Pershing continued to serve widely,particularly during the first six months of the war.However , when the action moved into moremountainous country, the M4A3 with the same en-gine, but lighter weight was preferred. By the end ofthe war, the old Sherman had again become the mostwidely used tank in action.

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Above: Men of the 9th Infantry Regiment riding on an M26 move to meet an enemy attack across the Naktong River,September 3, 1950.Below: An example of field camouflage applied to the Pershing. Another interesting point is the .30 caliber machine gunfitted to the forward pedestal mount. The .50 caliber weapon is retained on the rear mount.

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Tanks of the 73rd Battalion wait to board LSTs at Pusan for the move north to Inchon. Note the two versions of travelinggun locks in these photographs. The type shown below attached to the rear plate is the later production version.

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Above: An M26 of the 72nd Tank Battalion supporting troops of the 9th Infantry Regiment on the Naktong River line,September 1950.Below: A Pershing moves into position in the Tabu-dong area while the infantry awaits orders to move up.

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South KoreaArea of Operations, June-December 1950

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The T34 could also destroy the Pershing. This shows an 85mm hit on the front of an M46 Patton which had the samefrontal armor as the Pershing. The shot struck perfectly at thebase of the lug which provided a shot trap giving much thesame effect as a vertical plate. This illustrates the danger in-volved with any attachments that interrupt the smooth shapeof the front armor.

An 85 mm hit in the shot trap at the bottom of the Pershing'sgun shield. The shield has been removed and the turret rotatedto face the side of the tank.

Even the smaller enemy antitank guns could be deadly. The hitshown here on an M46 of the 64th Tank Battalion came froma Soviet built 57 mm gun.

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Above: Two M26Als entering Seoul on September 29,1950. These vehicles can easily be identified by the bore evacuator onthe 90 mm gun and the absence of fender mounted mufflers characteristic of the M46.Below: An M45 of the 6th Tank Battalion crosses the Kumho River on an underwater crossing of rocks and sand bags

reinforcing the river bed, 18 September 1950.

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CONCLUSION

The Pershing story might well be summarized bythe words of Captain Elmer Gray replying to the tankcrews at Aachen when they asked if the Pershing wasequal to the German King Tiger and Panther. Hisanswer was, "Hell no, but it is the best tank we haveyet developed and we should have had it a yearearlier". The reasons for the delay of the Pershingwere many, among them, the commitment of theArmy Ground Forces to the exploitation role and thedoctrine which specified that tanks should not fighttanks. The latter view, strongly supported by GeneralMcNair, retarded the development of heavily armedand armored tanks until experience with the Germanheavy weights proved that such encounters could notbe avoided.

Anticipating the requirements of 1944, GeneralBarnes, in October 1943, had urgently requestedimmediate production of 500 each of the T23,T25E1, and T26E1. The request was rejected on thegrounds that no requirement existed for these tanks.This resulted, in part, from the attitude of theArmored Force which wanted the 90 mm gun, butnot in a new tank. The Armored Force believed that a

new tank chassis would not be fully developed intime to be of effective use in the war and preferred tohave the familiar Sherman modified to mount theheavier gun. Army Ground Forces, on the other hand,did not object to the new tanks, but rejected the 90mm gun as tank armament. AGF opinion was that, ifthe tanks were equipped with the 90 mm gun, theywould be encouraged to engage in tank-versus-tankbat t les and abandon their proper role as amaneuvering element. In the AGF view, all antitankaction was the function of the artillery and tankdestroyers. This argument resulted in all productionrequests being rejected. Fortunately, experienceoverseas, where the Panthers and Tigers were beingencountered in Italy, broke the deadlock. Planningfor the invasion of Normandy was in full swing andGeneral Devers cabled from London requesting thehighest priority for the T26E1. In January 1944, 250T26E1s were authorized in addition to the tenalready ordered. General Barnes considered thesequantities inadequate and continued to press forproduction of 1000 new tanks.

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In addition to Korea, the Pershing served widely in Europe with the U.S. and other NATO forces. An M26 of the 63rd TankBattalion crossing the Main River at Aschaffenburg, Germany during Exercise "Combine" in October 1951.

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The battle against the 90 mm gun as tankarmament was not yet dead and in April 1944, AGFmade the ridiculous request that 6000 T25E1 andT26E1 tanks be produced with 75 mm and 76 mmguns respectively. Ordnance parried with thesuggestion that such a program be given low priority,since both weapons were being supplied in the lighttank M24 and the medium tank M4. Luckily, theEuropean Theater again stepped in and, shortlybefore D-Day, requested that all production of 75mm and 76 mm medium tanks be stopped. In thefuture, they wanted only the 90 mm gun and the 105mm howitzer as tank armament. After D-Day and theNormandy battles with the German Panthers andTigers, the importance of a high powered gun finallyreached full realization. A less desirable result of theexperience was the emphasis placed on heavier armorand the loss of interest in the T25E1. It was onlynatural for the troops to want as much armorprotection as they could get and certainly as much ason the enemy's tanks. However, to carry thenecessary weight and still retain good mobility overrough terrain required a more powerful engine thanthe Ford GAF. Such engines were under development

for the new heavy tanks, but were not yet inproduction by the spring of 1945. The T25E1provided a much better balance between firepower,mobility, and armor with the 500 h.p. engineavailable.

Based on his experience, General Harmon saidthat the ideal tank should have the most powerfulgun available, followed by the best mobility and thenas much armor as possible, without interfering withthe first two. Modern tank development in Europehas followed this trend, with the Leopard in Germanyand the AMX 30 in France. Both vehicles emphasizefirepower and mobility, with armor limited to thatnecessary to provide protection against automaticweapons such as the Soviet 57 mm antiaircraft guns.It is interesting to note that the T25E1 closelyapproached this same formula and might have been abetter choice for development than its heavierbrother. However, like other phases of the T20program, it provided information for future designsand this was perhaps the greatest value of the series.The wide range of components and design conceptsinvestigated during this period established the basisfor modern tank development in this country.

Marine Pershings push north to Wonju, Korea against the Chinese Communist Forces, February 1951.

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PART IV

REFERENCE DATA

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THE PERSHING, PANTHER, AND TIGER IA COMPARISON

When the Pershing was introduced into battle inearly 1945, German armored power was representedby the Panther, the Tiger I, and the Tiger II. The highpowered 8.8 cm KwK 43 and extremely heavy armorof the latter placed it in the category of a heavy tank,far superior in striking power and protection to thePershing. The Pershing was not designed to competewith such a vehicle on a tank versus tank basis. TheTiger I, however, had been studied since its introduc-tion in late 1942 and it exercised considerable influ-ence on the final Pershing design, since one objectivewas to provide a medium tank with equivalent fire-power and protection. The Panther, designed by theGermans after the encounter with the Soviet T34,had been developed through three models into asuperb fighting vehicle intended to become the stand-

ard of the Panzer troops. Major production planswere centered around the Panther and further devel-opment was in progress. If the war had continued, thePanther would have accounted for a much higher per-centage of the German armored force. It is interestingto compare the Pershing with the Panther as well asthe Tiger I, the tank it was designed to defeat. Themajor characteristics of all three tanks are listed inthe tables and some of the more important items arecovered in the following brief discussion.

The Pershing, Panther, and Tiger I were closeenough in fighting power so that each could defeatthe others under favorable circumstances. As de-scribed in Part I of this book, the Pershing on occa-sion destroyed both German vehicles and was in turnknocked out by them. The purpose of this compari-

Panzerkampfwagen V, Ausfuehrung G, Panther

son is to determine their relative standing in regard tothe various tank design parameters. Any such com-parative evaluation must first consider the basicdesign factors of firepower, mobility, and protection.Other qualities such as reliability, ease of transport,and crew comfort certainly have an important effect,but once committed to battle, the survival of the tankrests mainly on the three prime considerations.

In tank versus tank combat, firepower, as exem-plified by armor penetration performance, is of thegreatest importance. The ability of the main weaponto destroy the enemy tank at long range from anyangle simplifies the tactical problem and reduces therequirements for maneuver and armor protection.Closely tied to the requirement for a powerful gun isthe necessity for adequate fire control equipment topermit rapid and accurate engagement of the enemyat the maximum effective range.

Panzerkampfwagen VI, Ausfuehrung E, Tiger I

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Medium Tank M26, General Pershing

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All three tanks mounted powerful weapons andtheir armor piercing performance overlapped some-what, with the variety of ammunition available. The90 mm gun M3 of the Pershing and the 8.8 cmKwK 36 of the Tiger I gave quite similar results whenusing the same type of APCBC ammunition with amuzzle velocity of approximately 2650 ft/sec. ThePanther's 7.5 cm KwK 42, with a 400 ft/sec increasein muzzle velocity, obtained greater armor penetra-tion than either of the larger weapons despite itslighter projectile weight. The muzzle velocity of thelate production 90 mm APCBC ammunition (APCM82) was increased to 2800 ft/sec, but very littlewas available prior to the end of the war in Europe.The higher muzzle velocity gave the 90 superiorityover the Panther's gun at ranges exceeding about1000 yards, since the velocity did not drop off asrapidly with the heavier projectile. The new 90 mmT33 shot, heat treated to a higher hardness level, alsoshowed superiority, particularly at the longer ranges.Introduction of the APCR type lightweight shot withthe tungsten carbide core (HVAP T30E16) alsoincreased the performance of the 90. Similar ammuni-tion was developed for the German weapons, butproduction was halted due to shortages of tungsten.In spite of the great variety of results obtainable withdifferent types of ammunition, the fact remains that7.5 cm KwK 42 showed superior armor penetrationusing the standard APCBC projectiles readily availableduring the latter months of the war. The completeAPCBC round for the Panther's gun weighed about31 pounds compared to 43 and 34 pounds for thoseof the Pershing and Tiger I respectively. The lighterweight made the ammunition easier to handle in thetank turret, increasing the rate of fire. The larger gunscould, of course, fire a higher capacity high explosiveshell, but they were less effective as the hole punchersrequired for tank versus tank action. On this basis thePanther must be rated first in regard to firepowerfollowed by the Pershing and then the Tiger I.

The power to weight ratio and the unit groundpressure provide two readily obtainable measures ofmobility for an armored fighting vehicle. On the firstcount, the Panther was clearly superior with a ratio of13.8 gross horsepower per short ton compared toapproximately 11 horsepower per ton for the Persh-

ing and Tiger I. On the basis of ground pressure, thePershing and Panther were equal with a unit pressureof 12.5 psi compared to 13.9 psi for the Tiger I. Eventhe 13.9 psi value was obtainable only through theuse of 28.5 inch wide battle tracks which extendedthe overall vehicle width to 147 inches. In compari-son, the overall width of the Pershing and Pantherwere 138 and 129 inches respectively. The smallerwidth of the Panther was a definite advantage innegotiating narrow streets and bridges. In regard tothe latter, the overall weight of the tank was impor-tant. The Pershing had the advantage of being almostfour tons lighter than the Panther and over 16 tonslighter than the Tiger I. Considering all of these fac-tors, the Panther once again must be rated firstfollowed by the Pershing and the Tiger I.

Good practice in the design of armor requiresbalanced protection. This means that all parts of avehicle should have equal protection from attackfrom any one direction and, if there is any variation,the greatest protection should be applied to the areamost likely to be hit. Both the Pershing and thePanther violated this principle. The sloped front hullarmor on both tanks was far stronger than the gunshield or turret front. Thus the weakest area from thefront was the turret, which also had the highestprobability of being hit. The actual thickness of thegun shield was quite close for all three tanks givingapproximately the same degree of protection. Thelower height of the Pershing was a decided advantageover the Panther and Tiger, reducing the chance ofhits on the turret. Considering only the weakest areasfrom each direction, the three tanks were approx-imately equal in protection from the front and thePershing and Tiger I were slightly superior from thesides and rear. One advantage of the Panther designshould also be mentioned. The Panther turret was setback on the hull far enough so that a shot whichricocheted from the glacis plate would miss the gunshield. A similar ricochet on the Pershing would strikethe gun shield.

The reader can make further comparisons usingthe data in the tables. However, based on the criteriaof firepower, mobility, and protection, the Pantherwould have to be ranked first followed by the Persh-ing and lastly the Tiger I.

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201

GENERAL DATACrewLength: Gun forwardLength: Without gunGun Overhang:Width: OverallHeight:Tread:Ground Clearance:Fire Height:Turret Ring Diameter: (inside)Weight, Combat Loaded:Power to Weight Ratio: GrossGround Pressure: 0 penetration

ARMORType:Hull Thickness:

Front, upperlower

Sides, upper frontupper rearlower frontlower rear

RearTopFloor, front

rearTurret Thickness:

Gun ShieldFrontSidesRearTop

ARMAMENTPrimary:

TraverseElevation

Secondary:

AMMUNITIONPrimary:Secondary:

ENGINEMake and Model:Type:Displacement:Horsepower: Gross

POWER TRAINTransmission:Steering:

RUNNING GEARSuspension:Tracks: width

ground contact lengthshoes/track

PERFORMANCEMaximum Speed: roadMaximum Grade:Maximum Trench:Maximum Vertical Wall:Maximum Fording Depth:Cruising Range: roads

Medium Tank M26Pershing

5340.5 inches (865cm)249.1 inches (633cm)91.4 inches (232 cm)

138.3 inches (351cm)109.4 inches (278cm)110 inches (279cm)

17.2 inches (44cm)78 inches (198cm)69 inches (175cm)

92,355 pounds10.8 hp/ton

12.5 psi

Homogeneous, rolled & cast

4.0 inches (102mm) @ 46 deg.3.0 inches (76mm) @ 53 deg.3.0 inches (76mm) @ 0 deg.2.0 inches (51mm) @ 0 deg.3.0 inches (76mm) @ 0 deg.2.0 inches (51mm) @ 0 deg.2.0 inches (51mm) @ 10 deg.0.875 ins. (22mm) @ 90 deg.1.0 inches (25mm) @ 90 deg.0.5 inches (13mm) @ 90 deg.

4.5 inches (114mm) @ 0 deg.4.0 inches (102mm) @ 0 deg.3.0 inches (76mm) @ 0 deg.3.0 inches (76mm) @ 0 deg.1.0 inches (25mm) @ 90 deg.

90mm Gun M 3360 deg., power & manual+20 to -10 degrees, manual(1) .30 cal. MG coaxial(1) .30 cal. MG bow mount(1) .50 cal. MG AA mount

70 rounds 90mm5000 rounds .30 cal.550 rounds .50 cal.

Ford GAFLiquid cooled, V-81100 cubic inches (18.03L)500 hp @ 2600 rpm

TorqmaticControlled differential

Torsion bar24 inches (61cm)153.5 inches (390cm)82

25 miles/hour60 per cent8 feet (245cm)46 inches (117cm)48 inches (122cm)100 miles, approx.

PzKpfw V, ausf. GPanther

5348.8 inches (886cm)273 inches (693.5cm)

75.8 inches (192.5cm)128.8 inches (327cm)118 inches (299.5cm)103 inches (268cm)

22 inches (56cm)91 inches (230cm)65 inches (165cm)

99,873 pounds13.8 hp/ton

12.5 psi

Homogeneous, rolled

3.1 inches (80mm) @ 55 deg.3.1 inches (80mm) @ 35 deg.

.6 inches (40mm) @ 30 deg.

.6 inches (40mm) @ 30 deg.

.6 inches (40mm) @ 0 deg.

.6 inches (40mm) @ 0 deg.

.6 inches (40mm) @ 30 deg.0.6 inches (15mm) @ 90 deg.0.8 inches (20mm) @ 90 deg.0.5 inches (13mm) @ 90 deg.

4.7 inches (120mm) @ 0 deg.3.9 inches (100mm) @ 10 deg.1.8 inches (45mm) @ 25 deg.1.8 inches (45mm) @ 28 deg.0.6 inches (15mm) @ 84-90 deg.

7.5cm KwK 42360 deg., power & manual+20 to -4 degrees, manual(1) 7.92 MG coaxial(1) 7.92 MG bow mount(1) 7.92 MG AA mount

82 rounds 7.5 cm4200 rounds 7.92mm

Maybach HL 230 P30Liquid cooled, V-121457 cubic inches (23.88L)690 hp (700PS) @ 3000 rpm

ZF AK 7-200MAN, multigeared

Double torsion bar26 inches (66cm)154.3 inches (392cm)87

28 miles/hour60 per cent8 feet (245cm)35. 5 inches (90cm)75 inches (190cm)124 miles

PzKpfw VI, ausf. ETiger I

5333 inches (846cm)249 inches (632 cm)

84 inches (214cm)147 inches (373cm)114 inches (290cm)111 inches (282cm)

17 inches (43cm)73 inches (185cm)73 inches (185cm)125,400 pounds

11.0 hp/ton13.9 psi

Homogeneous, rolled

4.0 inches (102mm) @ 24 deg.2.4 inches (62mm) @ 60-80 deg.3.2 inches (82mm) @ 0 deg.3.2 inches (82mm) @ 0 deg.2.4 inches (62mm) @ 0 deg.2.4 inches (62mm) @ 0 deg.3.2 inches (82mm) @ 8 deg.1 .0 inches (26mm) @ 90 deg.1.0 inches (26mm) @ 90 deg.

4.3 inches (110mm) @ 0 deg.4.0 inches (102mm) @ 10 deg.3.2 inches (82mm) @ 0 deg.3.2 inches (82mm) @ 0 deg.1.0 inches (26mm) @ 81 deg.

8.8cm KwK 36360 deg., power & manual+ 17 to -6.5 degrees, manual(1) 7.92 MG coaxial(1) 7.92 MG bow mount(1) 7.92 MG AA mount

92 rounds 8.8cm5 100 rounds 7.92mm

Maybach HL 230 p45Liquid cooled, V-121457 cubic inches (23.88L)690 hp (700 PS) @ 3000 rpm

Maybach OlvarHenschel L600C

Torsion bar28.5 inches (72.5cm)158 inches (401cm)95

23 miles/hour75 per cent7.5 feet (229cm)31 inches (7 9cm)48 (122cm) or 156 (396cm) ins.73 miles

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PzKpfw V ausf. G, Panther

Medium Tank M26 (T26E3)

PzKpfw VI ausf. E, Tiger I

The low, wide silhouette of the Pershing is obvious particularly when compared with the Panther. The gun overhang was alsomuch greater on the Pershing than for the other two tanks.

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VEHICLE DATA SHEETS

Specifications for each of the major vehiclesdescribed in this book are outlined in the followingdata sheets. An effort has been made to obtain com-parable values for each item despite the wide varia-tions found in the official documents. Dimensionssuch as length, width, and height varied widelydepending on the source. Lengths, for example, oftendid not indicate the position of the gun or if sand-shields and a towing pintle were included. The heightmeasured in the field varied with the load and theresulting spring compression. Where possible, theoriginal design dimensions are used, obtained fromthe arsenal drawings. If these were not available, acomparable value was estimated using the measure-ments taken during tests at Aberdeen Proving Groundand Fort Knox.

Most of the terms used in the data sheets are selfexplanatory, however, some may be clarified byfurther discussion. For example, the tread is thewidth measured between track centers. The fireheight is the distance measured from the ground tothe centerline of the main weapon bore, when theweapon is aimed forward at zero elevation.

Engine power is listed as gross horsepower andnet horsepower. The gross horsepower refers to themaximum power delivered at the output shaft of theengine including only those accessories essential to

the operation of the engine. The effect of fans, gener-ators, air cleaners, etc. is excluded from these mea-surements. The net horsepower is the power actuallydelivered at the output shaft as installed in the vehicleincluding all of the accessories. The same criteriaapply to the measurement of the gross and nettorque.

The ground contact length at zero penetration isdefined as the distance between the centers of thefirst and last road wheels. This value is used to com-pute the ground contact area for determination of theground pressure. Combat weights are used for all cal-culations.

The stowage of the experimental vehicles variedduring their life reflecting the results of the testingprogram and changing user requirements. Early pilottanks were fitted with a .30 caliber antiaircraftmachine gun. This was later replaced by the .50 cali-ber weapon standard on all U.S. tanks.

Ballistic tests on the Pershing showed thedrivers' auxiliary periscopes to be vulnerable to theblast from high explosive shells detonating against theturret. To strengthen the hull roof against this type ofattack, the auxiliary periscopes were eliminated fromthe late production vehicles. As can be seen in photo-graphs of the T26E5 and other late production tanks,only the hatch cover periscope are retained.

203

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MEDIUM TANK T20

204

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 294 inchesLength: Gun to rear, over sandshields 245 inchesLength: Over sandshields, w/o gun 227 inchesGun Overhang: Gun forward 67 inchesWidth: Over sandshields 123 inchesHeight: Over mg mount 96 inchesTread: 102 inchesGround Clearance: 17 inchesFire Height: 75 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 65,758 poundsWeight, Unstowed: 60,704 poundsPower to Weight Ratio: Net 13.7 hp/ton

Gross 15.2 hp/tonGround Pressure: Zero penetration 13.5 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 2.5 inches 47 degreesLower 2.5 inches 53 degrees

Sides 2.0 inches 0 degreesRear 1.5 inches 10 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Front 3.5 inches 0 degreesSides 2.5 inches 0 to 13 degreesRear 2.5 inches 0 degreesTop 0.75 inches 90 degrees

ARMAMENTPrimary: 76 mm Gun M1A1 in Mount T79 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +25 to -10 degreesFiring Rate: (max) 20 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary:(1) .30 caliber MG M1919A4 flexible AA mount on turret*(1) .30 caliber MG M1919A4 coaxial w/76mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (1) .45 caliber SMG M1928A1

AMMUNITION70 rounds 76mm 12 hand grenades540 rounds .45 caliber7000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope T92 Azimuth Indicator M19Periscope M4 Gunner's Quadrant Mlwith telescope Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Hatch Periscope M6 (1)Gunner None Periscope M4 (1)Loader Hatch Periscope M6 (1)

Total Periscopes: M4 (1), M6 (6)

*Early armament and stowage, .30 caliber AA MG later replaced by a.50 caliber weapon

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry196 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.4:1Gear Ratios: 1st 1.63:1 3rd 0.39:1

2nd 0.74:1 reverse 1.17:1Steering: Controlled differential

Bevel Gear Ratio: 2.434:1 Steering Ratio: 1.515:1Brakes: Mechanical, external contractingFinal Drive: Spur gear Gear Ratio: 2.84:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.038 inchesRUNNING GEARSuspension: Horizontal volute spring

12 wheels in 6 bogies (3 bogies/track)Tire Size: 20 x 9 inches6 track return rollers (3/track)Adjustable idler at front of each trackIdler Size: 22 x 9 inchesShock absorbers fitted on front and rear bogies

Tracks: Outside guide, T48 and T51Type: (T48) Double pin, 16.56 inch width, chevron

(T51) Double pin, 16.56 inch width, smoothPitch: 6 inchesShoes per Vehicle: 158 (79/track)Ground Contact Length: 147 inches

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCMain Generator: (2) 24 volts, 50 amperes, driven by power take-off

from main engineAuxiliary Generator: (1) 24 volts, 125 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 30 miles/hour

Short periods, level 35 miles/hourMaximum Tractive Effort: TE at stall 40,000 pounds

Per Cent of Vehicle Weight: TE/W 60.8 per centMaximum Grade: 58 per centMaximum Trench: 7.5 feetMaximum Vertical Wall: 24 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 65 feetCruising Range: Roads approx. 150 miles

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MEDIUM TANK T20E3

205

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 294 inchesLength: Gun to rear, over sandshields 245 inchesLength: Over sandshields, w/o gun 227 inchesGun Overhang: Gun forward 67 inchesWidth: Over sandshields 127 inchesHeight: Over mg mount 97 inches

Tread: 105 inchesGround Clearance: 16 inchesFire Height: 76 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 67,500 poundsWeight, Unstowed: 62,500 poundsPower to Weight Ratio: Net 13.3 hp/ton

Gross 14.8 hp/tonGround Pressure: Zero penetration 12.8 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 2.5 inches 47 degreesLower 2.5 inches 53 degrees

Sides 2.0 inches 0 degreesRear 1.5 inches 10 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Front 3.5 inches 0. degreesSides 2.5 inches 0 to 13 degreesRear 2.5 inches 0 degreesTop 0.75 inches 90 degrees

ARMAMENTPrimary: 76mm Gun M1A1 in Mount T79 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +25 to -10 degreesFiring Rate: (max) 20 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret*(1) .30 caliber MG M1919A4 coaxial w/76mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (1) .45 caliber SMG M1928A1

AMMUNITION68 rounds 76mm 12 hand grenades300 rounds .50 caliber600 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Dkect Indirect

Telescope T92 Azimuth Indicator M19Periscope M4 Gunner's Quadrant Mlwith telescope Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Hatch Periscope M6 (1)Gunner None Periscope M4 (1)Loader Hatch Periscope M6 (1)

Total Periscopes: M4 (1), M6 (6)

*Late armament and stowage, a .30 caliber AA MG was originallyspecified

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry196 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.4:1Gear Ratios: 1st 1.63:1 3rd 0.39:1

2nd 0.74:1 reverse 1.17:1Steering: Controlled differential

Bevel Gear Ratio: 2.434:1 Steering Ratio: 1.515:1Brakes: Mechanical, external contractingFinal Drive: Spur gear Gear Ratio: 2.84:1Drive Sprocket: At rear of vehicle with 27 teeth

Pitch Diameter: 25.054 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 4.5 inches6 dual track return rollers (3/track)Final version equipped with 10 track return rollers (5/track)Dual compensating idler at front of each trackIdler Size: 24.5 x 4.5 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, cast steelType: Single pin, 18 inch widthPitch: 6 inches ,Shoes per Vehicle: 166 (83/track)Ground Contact Length: 145.2 inches, left side

148.7 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCMain Generator: (2) 24 volts, 50 amperes, driven by power take-off

from main engineAuxiliary Generator: (1) 24 volts, 125 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) l 1/2 quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 30 miles/hour

Short periods, level 35 miles/hourMaximum Tractive Effort: TE at stall 40,000 pounds

Per Cent of Vehicle Weight: TE/W 59.3 per centMaximum Grade: 50 per centMaximum Trench: 7.5 feetMaximum Vertical Wall: 24 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 65 feetCruising Range: Roads approx. 150 miles

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MEDIUM TANK T22

206

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 293 inchesLength: Gun to rear, over sandshields 253 inchesLength: Over sandshields, w/o gun 240 inchesGun Overhang: Gun forward 53 inchesWidth: Over sandshields 123 inchesHeight: Over mg mount 96 inchesTread: 102 inchesGround Clearance: 19 inchesFire Height: 77 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 69,300 poundsWeight, Unstowed: 64,246 poundsPower to Weight Ratio: Net 13.0 hp/ton

Gross 14.4 hp/tonGround Pressure: Zero penetration 14.2 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 2.5 inches 47 degreesLower 2.5 inches 53 degrees

Sides 2.0 inches 0 degreesRear 1.5 inches 10 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Front 3.5 inches 0 degreesSides 2.5 inches 0 to 13 degreesRear 2.5 inches 0 degreesTop 0.75 inches 90 degrees

ARMAMENTPrimary: 76mm Gun M1A1 in Mount T79 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +25 to -10 degreesFiring Rate: (max) 20 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret*(1) .30 caliber MG M1919A4 coaxial w/76mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (1) .45 caliber SMG M1928A1

AMMUNITION68 rounds 76mm 12 hand grenades300 rounds .50 caliber600 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope T92 Azimuth Indicator M19Periscope M4 Gunner's Quadrant M1with telescope Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Hatch Periscope M6 (1)Gunner None Periscope M4 (1)Loader Hatch Periscope M6 (1)

Total Periscopes: M4 (1), M6 (6)*Late armament and stowage, a .30 caliber AA MG was originallyspecified

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry200 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINClutch: Dry disc, 2 plateTransmission: Synchromesh, 5 speeds forward, 1 reverse

Gear Ratios: 1st 7.554:1 4th 1.108:12nd 3.105:1 5th 0.733:13rd 1.768:1 reverse 5.646:1

Steering: Controlled differentialBevel Gear Ratio: 3.53:1 Steering Ratio: 1.515:1

Brakes: Mechanical, external contractingFinal Drive: Spur gear Gear Ratio: 2.84:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.038 inchesRUNNING GEARSuspension: Horizontal volute spring

12 wheels in 6 bogies (3 bogies/track)Tire Size: 20 x 9 inches6 track return rollers (3/track)Adjustable idler at front of each trackIdler Size: 22 x 9 inchesShock absorbers fitted on front and rear bogies

Tracks: Outside guide, T48 and T51Type: (T48) Double pin, 16.56 inch width, chevron

(T51) Double pin, 16.56 inch width, smoothPitch: 6 inchesShoes per Vehicle: 158 (79/track)Ground Contact Length: 147 inches

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCMain Generator: (1) 24 volts, 50 amperes, driven by power take-off

from main engineAuxiliary Generator: (1) 24 volts, 125 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hourMaximum Tractive Effort: TE at stall 57,600 pounds

Per Cent of Vehicle Weight: TE/W 83.1 per centMaximum Grade: 60 per centMaximum Trench: 7.5 feetMaximum Vertical Wall: 24 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 65 feetCruising Range: Roads approx. 150 miles

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MEDIUM TANK T22E1

207

4 men254 inches240 inches240 inches

14 inches123 inches95 inches

102 inches19 inches77 inches69 inches

estimated 68,000 poundsestimated 63,000 pounds

13.2hp/ton14.7 hp/ton14.0 psi

GENERAL DATACrew:Length: Gun forward, over sandshieldsLength: Gun to rear, over sandshieldsLength: Over sandshields, w/o gunGun Overhang: Gun forwardWidth: Over sandshieldsHeight: Over mg mountTread:Ground Clearance:Fire Height:Turret Ring Diameter: (inside)Weight, Combat Loaded:Weight, Unstowed:Power to Weight Ratio: Net

GrossGround Pressure: Zero penetrationARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 2.5 inches 47 degreesLower 2.5 inches 53 degrees

Sides 2.0 inches 0 degreesRear 1.5 inches 10 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Front 3.5 inches 0 degreesSides 2.5 inches 0 degreesRear 2.5 inches 0 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 75mm Gun M3 in Mount M34 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +15 to -10 degreesFiring Rate: (max) 20 rounds/minuteLoading System: Automatic, hydraulicStabilizer System: Elevation only

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret*(1) .30 caliber MG M1919A4 coaxial w/75mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (1) .45 caliber SMG M1928A1

AMMUNITION64 rounds 75mm 12 hand grenades300 rounds .50 caliber600 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Periscope M4 Azimuth Indicator M19with Telescope Gunner's Quadrant MlM38 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Hatch and Periscope M6 (1)

pistol portGunner Hatch Periscope M4 (1)

Total Periscopes: M4 (1), M6 (5)Total Pistol Ports: Hull (0), Turret (1)

*Late armament and stowage, a .30 caliber AA MG was originallyspecified

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry200 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINClutch: Dry disc, 2 plateTransmission: Synchromesh, 5 speeds forward, 1 reverse

Gear Ratios: 1st 7.554:1 4th 1.108:12nd 3.105:1 5th 0.733:13rd 1.768:1 reverse 5.646:1

Steering: Controlled differentialBevel Gear Ratio: 3.53:1 Steering Ratio: 1.515:1

Brakes: Mechanical, external contractingFinal Drive: Spur gear Gear Ratio: 2.84:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.038 inchesRUNNING GEARSuspension: Horizontal volute spring

12 wheels in 6 bogies (3 bogies/track)Tire Size: 20 x 9 inches6 track return rollers (3/track)Adjustable idler at front of each trackIdler Size: 22 x 9 inchesShock absorbers fitted on front and rear bogies

Tracks: Outside guide, T48 and T51Type: (T48) Double pin, 16.56 inch width, chevron

(T51) Double pin, 16.56 inch width, smoothPitch: 6 inchesShoes per Vehicle: 158 (79/track)Ground Contact Length: 147 inches

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCMain Generator: (1) 24 volts, 50 amperes, driven by power take-off

from main engineAuxiliary Generator: (1) 24 volts, 125 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 4 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(1) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hourMaximum Tractive Effort: TE at stall 57,600 pounds

Per Cent of Vehicle Weight: TE/W 84.7 per centMaximum Grade: 60 per centMaximum Trench: 7.5 feetMaximum Vertical Wall: 24 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 62 feetCruising Range: Roads approx. 150 miles

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MEDIUM TANK T23, Pilot #2

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 298 inchesLength: Gun to rear, over sandshields 254 inchesLength: Over sandshields, w/o gun 237 inchesGun Overhang: Gun forward 61 inchesWidth: Over sandshields 123 inchesHeight: Over mg mount 96 inchesTread: 102 inchesGround Clearance: 19 inchesFire Height: 77 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 72,500 poundsWeight, Unstowed: 66,500 poundsPower to Weight Ratio: Net 12.4 hp/ton

Gross 13.8 hp/tonGround Pressure: Zero penetration 14.9 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 2.5 inches 47 degreesLower 2.0 inches 53 degrees

Sides 2.0 inches 0 degreesRear 1.5 inches 0 to 30 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Front 3.5 inches 0 degreesSides 2.5 inches 0 to 13 degreesRear 2.5 inches 0 degreesTop 0.75 inches 90 degrees

ARMAMENTPrimary: 76mm Gun M1A1 in Mount T79 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +25 to -10 degreesFking Rate: (max) 20 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary :(1) .30 caliber MG M1919A4 flexible AA mount on turret*(1) .30 caliber MG M1919A4 coaxial w/76mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (1) .45 caliber SMG M1928A1

AMMUNITION75 rounds 76mm 12 hand grenades450 rounds .45 caliber7000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope T92 Azimuth Indicator M19Periscope M4 Gunner's Quadrant Mlwith telescope Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Hatch Periscope M6 (1)Gunner None Periscope M4 (1)Loader Hatch Periscope M6 (1)

Total Periscopes: M4 (1), M6 (6)

*Early armament and stowage, .30 caliber AA MG later replaced by a.50 caliber weapon

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry179 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Electric drive with speed infinitely variable both forward

and reverseSteering: ElectricBrakes: ElectricFinal Drive: Spur gear Gear Ratio: 5.31:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.038 inchesRUNNING GEARSuspension: Vertical volute spring

12 wheels in 6 bogies (3 bogies/track)Tire Size: 20 x 9 inches6 track return rollers (1 at rear of each bogie)Adjustable idler at front of each trackIdler Size: 22 x 9 inches

Tracks: Outside guide, T48 and T51Type: (T48) Double pin, 16.56 inch width, chevron

(T51) Double pin, 16.56 inch width, smoothPitch: 6 inchesShoes per Vehicle: 158 (79/track)Ground Contact Length: 147 inches

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCBattery Charging Generator: 24 volts, 300 amperes, driven by power

take-off from main engineAuxiliary Generator: 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 35 miles/hourMaximum Tractive Effort: TE at stall 56,000 pounds

Per Cent of Vehicle Weight: TE/W 77.2 per centMaximum Grade: 60 per centMaximum Trench: 7.5 feetMaximum Vertical Wall: 24 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) pivotCruising Range: Roads approx. 150 miles

208

Page 205: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T23

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 297.5 inchesLength: Gun to rear, over sandshields 253.8 inchesLength: Over sandshields, w/o gun 236.9 inchesGun Overhang: Gun forward 60.6 inchesWidth: Over sandshields 122.5 inchesHeight: To top of cupola 98.8 inchesTread: 102 inchesGround Clearance: 19.1 inchesFire Height: 77 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 75,311 poundsWeight, Unstowed: 68,200 poundsPower to Weight Ratio: Net 11.9 hp/ton

Gross 13.3 hp/tonGround Pressure: Zero penetration 15.5 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 3.0 inches 47 degreesLower 2.5 inches 56 degrees

Sides, Front 2.0 inches 0 degreesRear 1.5 inches 0 degrees

Rear 1.5 inches 0 to 30 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 3.5 inches 0 degreesFront 3.0 inches 0 degreesSides 2.5 inches 0 to 13 degreesRear 2.5 inches 0 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 76mm Gun M1A1 in Mount M62 (T80) in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +25 to -10 degreesFiring Rate: (max) 20 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/76mm gun in turret(1) .30 caliber MG M1919A4 in bow mount(1) 2 inch Mortar M3 (smoke) fixed in turretProvision for (4) .45 caliber SMG M3Provision for (1) .30 caliber Carbine Ml

AMMUNITION66 rounds 76mm 12 rounds 2 in. (smoke)300 rounds .50 caliber 12 hand grenades600 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71D Azimuth Indicator M19Periscope M4A1 Gunner's Quadrant Mlwith Telescope M47 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M4A1 (1)Loader Hatch and Periscope M6 (1)

pistol portTotal Periscopes: M4A1 (1), M6 (6)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry179 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max) :Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Electric drive with speed infinitely variable both forward

and reverseSteering: ElectricBrakes: Electric and mechanical BendixFinal Drive: Spur gear Gear Ratio: 5.31:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.038 inchesRUNNING GEARSuspension: Vertical volute spring

12 wheels in 6 bogies (3 bogies/track)Tire Size: 20 x 9 inches6 track return rollers ( 1 at rear of each bogie)Adjustable idler at front of each trackIdler Size: 22 x 9 inches

Tracks: Outside guide, T48 and T51Type: (T48) Double pin, 16.56 inch width, chevron

(T51) Double pin, 16.56 inch width, smoothPitch: 6 inchesShoes per Vehicle: 158 (79/track)Ground Contact Length: 147 inches

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCBattery Charging Generator: 24 volts, 200 amperes, driven by power

take-off from main engineAuxiliary Generator: 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) l 1/2 quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 35 miles/hourMaximum Tractive Effort: TE at stall 56,000 pounds

Per Cent of Vehicle Weight: TE/W 74.4 per centMaximum Grade: 60 per centMaximum Trench: 7.5 feetMaximum Vertical Wall: 24 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) pivotCruising Range: Roads approx. 100 miles

209

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MEDIUM TANK T23E3

210

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 306 inchesLength: Gun to rear, over sandshields 253.8 inchesLength: Over sandshields, w/o gun 244.4 inchesGun Overhang: Gun forward 62 inchesWidth: Over sandshields 128 inchesHeight: To top of cupola 100.6 inchesTread: 105 inchesGround Clearance: 17.6 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 79,390 poundsWeight, Unstowed: 72,000 poundsPower to Weight Ratio: Net 11.3 hp/ton

Gross 12.6 hp/tonGround Pressure: Zero penetration 13.9 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 3.0 inches 47 degreesLower 2.5 inches 56 degrees

Sides, Front 2.0 inches 0 degreesRear 1.5 inches 0 degrees

Rear 1.5 inches 0 to 30 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 3.5 inches 0 degreesFront 3.0 inches 0 degreesSides 2.5 inches 0 to 13 degreesRear 2.5 inches 0 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 76mm Gun M1A1 in Mount M62 (T80) in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +25 to -10 degreesFiring Rate: (max) 20 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/76mm gun in turret(1) .30 caliber MG M1919A4 in bow mount(1) 2 inch Mortar M3 (smoke) fixed in turretProvision for (4) .45 caliber SMG M3Provision for (1) .30 caliber Carbine Ml

AMMUNITION84 rounds 76mm 12 rounds 2 in. (smoke)500 rounds .50 caliber 12 hand grenades600 rounds .45 caliber4000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71D Azimuth Indicator M19Periscope M4A1 Gunner's Quadrant Mlwith Telescope M47 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M4A1 (1)Loader Hatch and Periscope M6 (1)

pistol portTotal Periscopes: M4A1 (1), M6 (6)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry179 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Electric drive with speed infinitely variable both forward

and reverseSteering: ElectricBrakes: Electric and mechanical BendixFinal Drive: Spur gear Gear Ratio: 5.31:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.054 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 4.3 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 4.3 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, cast steelType: Single pin, 19 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 148.3 inches, left side

152.3 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCBattery Charging Generator: 24 volts, 200 amperes, driven by power

take-off from main engineAuxiliary Generator: 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, Ml9, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 35 miles/hourMaximum Tractive Effort: TE at stall 56,000 pounds

Per Cent of Vehicle Weight: TE/W 70.5 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 36 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) pivotCruising Range: Roads approx. 100 miles

Page 207: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T23 HVSS

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 308 inchesLength: Gun to rear, over sandshields 264 inchesLength: Over sandshields, w/o gun 237 inchesGun Overhang: Gun forward 71 inchesWidth: Over sandshields 137 inchesHeight: To top of cupola 98 inchesTread: 108 inchesGround Clearance: 18 inchesFire Height: 76 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 82,000 poundsWeight, Unstowed: 75,000 poundsPower to Weight Ratio: Net 11.0 hp/ton

Gross 12.2 hp/tonGround Pressure: Zero penetration ll.8 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 3.0 inches 47 degreesLower 2.5 inches 56 degrees

Sides, Front 2.0 inches 0 degreesRear 1.5 inches 0 degrees

Rear 1.5 inches 0 to 30 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 3.5 inches 0 degreesFront 3.0 inches 0 degreesSides 2.5 inches 0 to 13 degreesRear 2.5 inches 0 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 76mm Gun M1A1 in Mount M62 (T80) in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +25 to -10 degreesFiring Rate: (max) 20 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/76mm gun in turret(1) .30 caliber MG M1919A4 in bow mount(1) 2 inch Mortar M3 (smoke) fixed in turretProvision for (4) .45 caliber SMG M3Provision for (1) .30 caliber Carbine M1

AMMUNITION66 rounds 76mm 12 rounds 2 in. (smoke)300 rounds .50 caliber 12 hand grenades600 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71D Azimuth Indicator M19Periscope M4A1 Gunner's Quadrant Mlwith Telescope M47 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M4A1 (1)Loader Hatch and Periscope M6 (1)

pistol portTotal Periscopes: M4A1 (1), M6 (6)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry179 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Electric drive with speed infinitely variable both forward

and reverseSteering: ElectricBrakes: Electric and mechanical BendixFinal Drive: Spur gear Gear Ratio: 5.31:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.038 inchesRUNNING GEARSuspension: Horizontal volute spring

12 dual wheels in 6 bogies (3 bogies/track)Tke Size: 20 x 6.25 inches4 dual track return rollers (2/track)6 single track return rollers (3/track)Dual adjustable idler at front of each trackIdler Tire Size: 22 x 6.25 inchesShock absorbers fitted on each bogie

Tracks: Center guide, T80Type: (T80) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 158 (79/track)Ground Contact Length: 151 inches

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCBattery Charging Generator: 24 volts, 200 amperes, driven by power

take-off from main engineAuxiliary Generator: 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 35 miles/hourMaximum Tractive Effort: TE at stall 56,000 pounds

Per Cent of Vehicle Weight: TE/W 68.3 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 36 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) pivotCruising Range: Roads approx. 100 miles

211

Page 208: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T25, Püot #2

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 312 inchesLength: Gun to rear, over sandshields 270 inchesLength: Over sandshields, w/o gun 237 inchesGun Overhang: Gun forward 75 inchesWidth: Over sandshields 137 inchesHeight: To top of cupola 108 inchesTread: 108 inchesGround Clearance: 18 inchesFire Height: 77 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 84,210 poundsWeight, Unstowed: 78,810 poundsPower to Weight Ratio: Net 10.9 hp/ton

Gross 12.2 hp/tonGround Pressure: Zero penetration 12.3 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 3.0 inches 47 degreesLower 2.5 inches 56 degrees

Sides, Front 2.0 inches 0 degreesRear 1.5 inches 0 degrees

Rear 1.5 inches 0 to 30 degreesTop 0.75 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 3.5 inches 0 degreesFront 3.0 inches 0 degreesSides 2.5 inches 0 to 8 degreesRear 2.5 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun M3 (T7) in Mount T99 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mount(1) 2 inch Mortar M3 (smoke) fixed in turretProvision for (4) .45 caliber SMG M3Provision for (1) .30 caliber Carbine Ml

AMMUNITION50 rounds 90mm 12 rounds 2 in. (smoke)500 rounds .50 caliber 12 hand grenades720 rounds .45 caliber4500 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71C Azimuth Indicator M19Periscope M8A1 Gunner's Quadrant Mlwith Telescope T121 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M8A1 (1)Loader Hatch and Periscope M6 (1)

pistol portTotal Periscopes: M8A1 (1), M6 (6)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry179 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Electric drive with speed infinitely variable both forward

and reverseSteering: ElectricBrakes: Electric and mechanical BendixFinal Drive: Spur gear Gear Ratio: 5.31:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.038 inchesRUNNING GEARSuspension: Horizontal volute spring

12 dual wheels in 6 bogies (3 bogies/track)Tire Size: 20 x 6.25 inches4 dual track return rollers (2/track)6 single track return rollers (3/track)Dual adjustable idler at front of each trackIdler Tire Size: 22 x 6.25 inchesShock absorbers fitted on each bogie

Tracks: Center guide, T66 and T80Type: (T66) Single pin, 23 inch width

(T80) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 158 (79/track)Ground Contact Length: 149 inches

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCBattery Charging Generator: 24 volts, 200 amperes, driven by power

take-off from main engineAuxiliary Generator: 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 30 miles/hour

Short periods, level 34.5 miles/hourMaximum Tractive Effort: TE at stall 56,000 pounds

Per Cent of Vehicle Weight: TE/W 66.5 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 36 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) pivotCruising Range: Roads approx. 100 miles

212

Page 209: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T25E1

213

GENERAL DATACrew: 5 menLength: Gun forward, over pintle 323.3 inchesLength: Gun to rear, over sandshields 268.6 inchesLength: Over ss and pintle, w/o gun 247.8 inchesGun Overhang: Gun forward 75.5 inchesWidth: Over sandshields 127.0 inchesHeight: To top of cupola 109.4 inchesTread: 105 inchesGround Clearance: 17.2 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 77,590 poundsWeight, Unstowed: 70,000 poundsPower to Weight Ratio: Net 11.6 hp/ton

Gross 12.9 hp/tonGround Pressure: Zero penetration 13.6 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 3.0 inches 46 degreesLower 2.5 inches 53 degrees

Sides, Front 2.0 inches 0 degreesRear 1.5 inches 0 degrees

Rear, Upper 1.5 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 3.5 inches 0 degreesFront 3.0 inches 0 degreesSides 2.5 inches 0 to 8 degreesRear 2.5 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun M3 (T7) in Mount T99 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mount(1) 2 inch Mortar M3 (smoke) fixed in turretProvision for (5) .45 caliber SMG M3

AMMUNITION42 rounds 90mm 12 rounds 2 in. (smoke)500 rounds .50 caliber 12 hand grenades600 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71C Azimuth Indicator M19Periscope M8A1 Gunner's Quadrant Mlwith Telescope T121 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M8A1 (1)Loader Hatch Periscope M6 (1)

Total Periscopes: M8A1 (1), M6 (6)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200rpm1414 lb, dry202 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 2.08:1Brakes: Mechanical, external contractingFinal Drive: Spur gear Gear Ratio: 3.48:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 4.3 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 4.3 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, cast steelType: Single pin, 19 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 148.3 inches, left side

152.3 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 610 in rear of turretInterphone: RC 99, 4 stationsFlag Set M238, Panel Set AP50A, SpotlightFIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 30 miles/hour

Short periods, level 35 miles/hourMaximum Tractive Effort: TE at stall 53,000 pounds

Per Cent of Vehicle Weight: TE/W 68.3 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 40 feetCruising Range: Roads approx. 110 miles

Page 210: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T26

214

GENERAL DATACrew: 5 menLength: Gun forward, over sandshields 318.5 inchesLength: Gun to rear, over sandshields 270.0 inchesLength: Over sandshields, w/o gun 244.4 inchesGun Overhang: Gun forward 74.1 inchesWidth: Over sandshields 138 inchesHeight: To top of cupola 109 inchesTread: 110 inchesGround Clearance: 17.2 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 95,100 poundsWeight, Unstowed: 89,700 poundsPower to Weight Ratio: Net 9.5 hp/ton

Gross 10.5 hp/tonGround Pressure: Zero penetration 12.9psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear 2.0 inches 0 to 30 degreesTop 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 4.5 inches 0 degreesFront 4.0 inches 0 degreesSides 3.0 inches 0 to 8 degreesRear 3.0 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun M3 (T7) in Mount T99E1 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mount(1) 2 inch Mortar M3 (smoke) fixed in turretProvision for (4) .45 caliber SMG M3Provision for (1) .30 caliber Carbine Ml

AMMUNITION58 rounds 90mm 12 rounds 2 in. (smoke)500 rounds .50 caliber 12 hand grenades720 rounds .45 caliber4500 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indkect

Telescope M71C Azimuth Indicator M19Periscope M8A1 Gunner's Quadrant Mlwith Telescope T121 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M8A1 (1)Loader Hatch and Periscope M6 (1)

pistol portTotal Periscopes: M8A1 (1), M6 (6)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry179 gallons32 quarts

ENGINEMake and Model: Ford GANType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransmission: Electric drive with speed infinitely variable both forward

and reverseSteering: ElectricBrakes: Electric and mechanical BendixFinal Drive: Spur gear Gear Ratio: 6.5:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCBattery Charging Generator: 24 volts, 200 amperes, driven by power

take-off from main engineAuxiliary Generator: 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loaderInterphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hour

Short periods, level 28 miles/hourMaximum Tractive Effort: TE at stall 69,000 pounds

Per Cent of Vehicle Weight: TE/W 72.6 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 36 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) pivotCruising Range: Roads approx. 75 miles

Page 211: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T26E1

GENERAL DATACrew: 5 menLength: Gun forward, over pintle 324.6 inchesLength: Gun to rear, over sandshields 269 inchesLength: Over ss and pintle, w/o gun 249.1 inchesGun Overhang: Gun forward 75.5 inchesWidth: Over sandshields 138.3 inchesHeight: To top of cupola 109.4 inchesTread: 110 inchesGround Clearance: 17.2 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 87,350 poundsWeight, Unstowed: 81,300 poundsPower to Weight Ratio: Net 10.3 hp/ton

Gross 11.4 hp/tonGround Pressure: Zero penetration 12.1 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 4.5 inches 0 degreesFront 4.0 inches 0 degreesSides 3.0 inches 0 to 8 degreesRear 3.0 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun M3 (T7) in Mount T99E1 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mount(1) 2 inch Mortar M3 (smoke) fixed in turretProvision for (5) .45 caliber SMG M3

AMMUNITION42 rounds 90mm 12 rounds 2 in. (smoke)500 rounds .50 caliber 12 hand grenades600 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71C Azimuth Indicator M19Periscope M8A1 Gunner's Quadrant Mlwith Telescope T121 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M8A1 (1)Loader Hatch Periscope M6 (1)

Total Periscopes: M8A1 (1), M6 (6)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry202 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 2.08:1Brakes: Mechanical, external contractingFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 cast steelType: (T81) Single pin, 24 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 148.3 inches, left side

152.3 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 610 in rear of turretInterphone: RC 99, 4 stationsFlag Set M238, Panel Set AP50A, SpotlightFIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hour

Short periods, level 30 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 68.7 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 40 feetCruising Range: Roads approx. 100 miles

215

Page 212: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK M45 (T26E2)

GENERAL DATACrew: 5 menLength: Howitzer forward, over muffler 256.7 inchesLength: Howitzer to rear, over muffler and ss 254.3 inchesLength: over ss and muffler, w/o howitzer 254.3 inchesGun Overhang: Howitzer forward 2.4 inchesWidth: Over sandshields 138.3 inchesHeight: Over mg Mount 110.9 inchesTread: 110 inchesGround Clearance: 18.8 inchesFire Height: 80 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 93,000 poundsWeight, Unstowed: 86,000 poundsPower to Weight Ratio: Net 9.7 hp/ton

Gross 10.8 hp/tonGround Pressure: Zero penetration 13.2 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Howitzer Shield 8.0 inches 0 degreesFront 5.0 inches 0 degreesSides 5.0 to 3.0 inches 0 to 8 degreesRear 2.5 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 105mm Howitzer M4 in Mount M71 (T117) in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +35 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: Elevation only

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/105mm howitzer in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (5) .45 caliber SMG M3Provision for (1) .30 caliber Carbine M2 w/grenade launcher

AMMUNITION74 rounds 105mm 12 hand grenades550 rounds .50 caliber900 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENT*Primary Weapon: Direct Indkect

Telescope M76G Azimuth Indicator M20Periscope M10D Elevation Quadrant M9Elbow Telescope M62

Vision Devices: Direct IndirectDriver Hatch Periscope M13 (1)Asst. Driver Hatch Periscope M13 (1)Commander Vision cupola Periscope M15 (1)

and hatchGunner None Periscope M10D (1)Loader Hatch and Periscope M13 (1)

pistol portTotal Periscopes: M10D (1), M13 (3), M15 (1); In addition the follow-

ing spares are carried, M10D (1), M13 (4)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

*Late production vision devices, drivers' auxiliary periscopes eliminated

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry183 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loader; AN/VRC 3 in rear of turret onsome tanks (infantry communication)

Interphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hour

Short periods, level 30 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 64.5 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 100 miles

216

Page 213: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK M26 (T26E3)

217

GENERAL DATACrew: 5 menLength: Gun forward, over pintle 340.5 inchesLength: Gun to rear, over sandshields 285 inchesLength: Over ss and pintle, w/o gun 249.1 inchesGun Overhang: Gun forward 91.4 inchesWidth: Over sandshields 138.3 inchesHeight: To top of cupola 109.4 inchesTread: 110 inchesGround Clearance: 17.2 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 92,355 poundsWeight, Unstowed: 84,850 poundsPower to Weight Ratio: Net 9.7 hp/ton

Gross 10.8 hp/tonGround Pressure: Zero penetration 12.5 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 4.5 inches 0 degreesFront 4.0 inches 0 degreesSides 3.0 inches 0 to 8 degreesRear 3.0 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun M3 (T7) in Mount M67 (T99E2) in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (5) .45 caliber SMG M3Provision for (1) .30 caliber Carbine M2 w/grenade launcher

AMMUNITION70 rounds 90mm 12 hand grenades550 rounds .50 caliber900 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71C Azimuth Indicator M19Periscope M10F Gunner's Quadrant MlPeriscope M4A1, spare Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M10F (1)Loader Hatch and Periscope M6 (1)

pistol port

Total Periscopes: M10F (1), M6 (6)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry183 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506,(command tanks

only) on shelf in front of loader; AN/VRC 3 in rear of turret onsome tanks (infantry communication)

Interphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hour

Short periods, level 30 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 65.0 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 100 miles

Page 214: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T26E4

218

GENERAL DATACrew: 5 menLength: Gun forward, over pintle 406 inchesLength: Gun to rear, over sandshields 348 inchesLength: Over ss and pintle, w/o gun 249.1 inchesGun Overhang: Gun forward 157 inchesWidth: Over sandshields 138.3 inchesHeight: To top of cupola 109.4 inchesTread: 110 inchesGround Clearance : 17.2 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 96,000 poundsWeight, Unstowed: 88,000 poundsPower to Weight Ratio: Net 9.4 hp/ton

Gross 10.4 hp/tonGround Pressure: Zero penetration 13.0 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 4.5 inches 0 degreesFront 4.0 inches 0 degreesSides 3.0 inches 0 to 8 degreesRear 3.0 inches plus 0 to 5 degrees

counterweightTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90 mm Gun T15E2 in Mount Tl 19 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 4 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (5) .45 caliber SMG M3Provision for (1) .30 caliber Carbine M2 w/grenade launcher

AMMUNITION54 rounds 90mm 12 hand grenades440 rounds .50 caliber900 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENT*Primary Weapon: Direct Indirect

Telescope M71E4 Azimuth Indicator M200Periscope M10E4 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M13 (1)Asst. Driver Hatch Periscope M13 (1)Commander Vision cupola Periscope M15 (1)

and hatchGunner None Periscope M10E4 (1)Loader Hatch and Periscope Ml3 (1)

pistol portTotal Periscopes: M10E4 (1), M13 (3), M15 (1); In addition the follow-

ing spares are carried, M10E4 (1), M13 (4)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

*Late production vision devices, drivers' auxiliary periscopes eliminated

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry183 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loader; AN/VRC 3 in rear of turret onsome tanks (infantry communication)

Interphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 20 miles/hour

Short periods, level 25 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 62.5 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 100 miles

Page 215: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK T26E5

GENERAL DATACrew: 5 menLength: Gun forward, over pintle 340.5 inchesLength: Gun to rear, over sandshields 285 inchesLength: Over ss and pintle, w/o gun 249.1 inchesGun Overhang: Gun forward 91.4 inchesWidth: Over sandshields 148 inchesHeight: To top of cupola 109.4 inchesTread: With 23 inch tracks 110 inches

With 28 inch tracks 115 inchesGround Clearance: 17.2 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: 102,300 poundsWeight, Unstowed: 94,500 poundsPower to Weight Ratio: Net 8.8 hp/ton

Gross 9.7 hp/tonGround Pressure: Zero penetration, 23" trk 14.5 psi

28"trk 11.9 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 6.0 inches 46 degreesLower 4.0 inches 54 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 1.5 to 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 11.0 inches 0 degreesFront 7.5 inches 10 degreesSides 3.5 inches 0 to 8 degreesRear 5.0 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun M3 (T7) in Mount M67 (T99E2) in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 20 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (5) .45 caliber SMG M3Provision for (1) .30 caliber Carbine M2 w/grenade launcher

AMMUNITION70 rounds 90mm 12 hand grenades550 rounds .50 caliber900 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENT*Primary Weapon: Direct Indirect

Telescope M83C Azimuth Indicator M19Periscope M10F Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M13 (1)Asst. Driver Hatch Periscope M13 (1)Commander Vision cupola Periscope M15 (1)

and hatchGunner None Periscope M10F (1)Loader Hatch and Periscope M13 (1)

pistol portTotal Periscopes: M10F (1), M13 (3), M15 (1); In addition the follow-

ing spares are carried, M10F (1), M13 (4)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

*Late production vision devices, drivers' auxiliary periscopes eliminated

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200rpm1414 lb, dry183 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 4.47:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 2 6 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T80E1 w/5 inch end connectorsType: (T80E1) Double pin, 23 inch widthTotal Track Width: 28 inches with end connectorsPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loader; AN/VRC 3 in rear of turret onsome tanks (infantry communication)

Interphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 20 miles/hour

Short periods, level 25 miles/hourMaximum Tractive Effort: TE at stall 68,000 pounds

Per Cent of Vehicle Weight: TE/W 66.5 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMaximum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 80 miles

219

Page 216: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

MEDIUM TANK M26E1

GENERAL DATACrew: 5 menLength: Gun forward, over pintle 376 inchesLength: Gun to rear, over sandshields 321 inchesLength: Over ss and pintle, w/o gun 249.1 inchesGun Overhang: Gun forward 127 inchesWidth: Over sandshields 138.3 inchesHeight: To top of cupola 109.4 inchesTread: 110 inchesGround Clearance: 17.2 inchesFire Height: 78 inchesTurret Ring Diameter: (inside) 69 inchesWeight, Combat Loaded: estimated 94,600 poundsWeight, Unstowed: estimated 87,000 poundsPower to Weight Ratio: Net 9.5 hp/ton

Gross 10.6 hp/tonGround Pressure: Zero penetration 12.8 psiARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 4.5 inches 0 degreesFront 4.0 inches 0 degreesSides 3.0 inches 0 to 8 degreesRear 3.0 inches plus 0 to 5 degrees

counterweightTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun T54 in Mount T126 in turret

Traverse: Hydraulic and manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +15 to -10 degreesFiring Rate: (max) 6 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .50 caliber MG HB M2 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (5) .45 caliber SMG M3

AMMUNITION41 rounds 90mm 12 hand grenades1100 rounds .50 caliber (estimated)900 rounds .45 caliber2500 rounds .30 caliber (estimated)

FIRE CONTROL AND VISION EQUIPMENT*Primary Weapon: Direct Indirect

Telescope M71E4 Azimuth Indicator M20Periscope M10E4 Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M13 (1)Asst. Driver Hatch Periscope M13 (1)Commander Vision cupola Periscope M15 (1)

and hatchGunner None Periscope M10E4 (1)Loader Hatch and Periscope M13 (1)

pistol portTotal Periscopes: M10E4 (1), M13 (3), M15 (1); In addition the follow-

ing spares are carried, M10E4 (1), M13 (4)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

*Late production vision devices, drivers' auxiliary periscopes eliminated

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry183 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loader; AN/VRC 3 in rear of turret onsome tanks (infantry communication)

Interphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 20 miles/hour

Short periods, level 25 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 63.4 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 100 miles

220

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MEDIUM TANK M26E2

5 men335 inches285 inches244 inches

91 inches138 inches109 inches110 inches

17 inches78 inches69 inches

estimated 94,000 poundsestimated 86,500 pounds

15.0 hp/ton17.2 hp/ton13.3 psi

GENERAL DATACrew:Length: Gun forwardLength: Gun to rearLength: Without gunGun Overhang: Gun forwardWidth: Over sandshieldsHeight: To top of cupolaTread:Ground Clearance:Fire Height:Turret Ring Diameter: (inside)Weight, Combat Loaded:Weight, Unstowed:Power to Weight Ratio: Net

GrossGround Pressure: Zero penetrationARMORType: Turret, cast homogeneous steel; Hull, rolled and cast homogen-

eous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Gun Shield 4.5 inches 0 degreesFront 4.0 inches 0 degreesSides 3.0 inches 0 to 8 degreesRear 3.0 inches 0 to 5 degreesTop 1.0 inches 90 degrees

ARMAMENTPrimary: 90mm Gun M3 in Mount M67 in turret

Traverse: Hydraulic and Manual 360 degreesTraverse Rate: (max) 15 seconds/360 degreesElevation: Manual +20 to -10 degreesFiring Rate: (max) 8 rounds/minuteLoading System: ManualStabilizer System: None

Secondary:(1) .50 caliber MG HB M2 flexible AA mount on turret(1) .30 caliber MG M1919A4 coaxial w/90mm gun in turret(1) .30 caliber MG M1919A4 in bow mountProvision for (5) .45 caliber SMG M3Provision for (1) .30 caliber Carbine M2 w/grenade launcher

AMMUNITION70 rounds 90mm 12 hand grenades550 rounds .50 caliber900 rounds .45 caliber5000 rounds .30 caliber

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Direct Indirect

Telescope M71C Azimuth Indicator M19Periscope M10F Gunner's Quadrant M1Periscope M4A1, spare Elevation Quadrant M9

Vision Devices: Direct IndirectDriver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchGunner None Periscope M10F (1)Loader Hatch and Periscope M6 (1)

pistol portTotal Periscopes: M10F (1), M6 (6)Total Pistol Ports: Hull (0), Turret (1)Vision Cupolas: (1) w/6 vision blocks on turret top

ENGINEMake and Model: Continental AV-1790-1 or -3Type: 12 cylinder, 4 cycle, 90 degree veeCooling System: Air Ignition: -1 battery, -3 magnetoDisplacement: 1790 cubic inchesBore and Stroke: 5.75 x 5.75 inchesCompression Ratio: 6.5:1Net Horsepower (max): 704 hp at 2800 rpmGross Horsepower (max): 810 hp at 2800 rpmNet Torque (max): 1440 ft-lb at 2200 rpmGross Torque (max): 1610 ft-lb at 2200 rpmWeight: 2380 lb, dryFuel: 80 octane gasoline 190 gallonsEngine Oil: 72 quartsPOWER TRAINTransmission: Cross-drive, 2 ranges forward, 1 reverse

Single stage hydraulic converterStall Multiplication: 5.2:1Overall Usable Ratios: low 15.5 reverse 20.6

high 7.1Steering Control: Mechanical wobble stick

Steering Rate: 5.7 RPMBrakes: Multiple discFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCMain Generator: (1) 24 volts, 175 amperes, driven by power take-off

from main engineAuxiliary Generator: (1) 24 volts, 175 amperes, driven by the auxiliary

engineBattery: (4) 12 voltsCOMMUNICATIONSRadio: SCR 508 or 528 in rear of turret; SCR 506 (command tanks

only) on shelf in front of loader; AN/VRC 3 in rear of turret onsome tanks (infantry communication)

Interphone: (part of radio) 5 stationsFlag Set M238, Panel Set AP50A, SpotlightFlares: 3 each, M17, M18, M19, and M21 (command tanks only)Ground Signals Projector M4 (command tanks only)FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1½ quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hourMaximum Tractive Effort: TE at stall 81,000 pounds

Per Cent of Vehicle Weight: TE/W 86.2 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) pivotCruising Range: Roads 175 miles

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8 inch HOWITZER MOTOR CARRIAGE T84

GENERAL DATACrew: 8 menLength: Overall 273 inchesWidth: Over sandshields 136.3 inchesHeight: Overall 125 inchesTread: 110 inchesGround Clearance: 17.7 inchesWeight, Combat Loaded: estimated 82,000 poundsWeight, Unstowed: 76,660 poundsPower to Weight Ratio: Net 11.0 hp/ton

Gross 12.2 hp/tonGround Pressure: Zero penetration ll.8 psiARMORType: Rolled homogeneous steel, welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 1.0 inches 64 degreesLower 1.0 inches 35 degrees

Sides, Upper 0.5 inches 0 degreesLower 1.0 inches 0 degrees

Rear 0.5 inches 30 degreesTop 0.5 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesHowitzer Shield 0.5 inches 40 degreesARMAMENTPrimary: 8 inch Howitzer Ml in mount at rear of hull

Traverse: Manual 15 degrees each sideElevation: Manual +60 to -5 degreesFiring Rate: (max) 1 round/minuteLoading System: Manual

Secondary:Provision for (1) .30 caliber Rifle M1903A3Provision for (7) .30 caliber Carbines M2Provision for (1) Grenade Launcher M8

AMMUNITION6 rounds 8 inch 12 hand grenades10 rifle grenades

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Telescope M69E2

Panoramic Telescope M12Gunner's Quadrant M1

Vision Devices: Direct IndirectDriver Vision cupola None

and hatchAsst. Driver Vision cupola None

and hatchVision Cupolas: (2) w/4 vision blocks on hull roof

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry200 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At front of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at rear of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 149.6 inches, right side

153.4 inches, left sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 75 amperes, driven by power take-off from

main engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 610 or 628 in left sponson compartmentInterphone: RC 99, 4 stationsFIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(1) 1 1/2 quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 73.2 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 36 inchesMaximum Fording Depth: 36 inchesMinimum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 100 miles

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8 inch GUN MOTOR CARRIAGE T93

GENERAL DATACrew: 8 menLength: Overall 447 inchesWidth: With 23 inch tracks, w/o ss 133 inches

With 28 inch tracks, w/o ss 143 inchesHeight: Overall 126.9 inchesTread: With 23 inch tracks 110 inches

With 28 inch tracks 115 inchesGround Clearance: 18.7 inchesWeight, Combat Loaded: 132,600 poundsWeight, Unstowed: estimated 128,000 poundsPower to Weight Ratio: Net 6.8 hp/ton

Gross 7.5 hp/tonGround Pressure: Zero penetration, 23" trk 16.0 psi

28" trk 13.2 psiARMORType: Rolled homogeneous steel, welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 1.0 inches 64 to 72 degreesLower 1.0 inches 40 degrees

Sides, Upper 0.5 inches 0 degreesLower 1.0 inches 0 degrees

Rear 0.5 inches 10 degreesTop 0.875 inches 90 degreesFloor 1.0 inches 90 degrees

Gun Shield 0.5 inches 30 degreesARMAMENTPrimary: 8 inch Gun Ml in Mount T31 at rear of hull

Traverse: Manual 12 degrees each sideElevation: Manual +65 to 0 degreesFiring Rate: (max) 1 round/minuteLoading System: Manual

Secondary:Provision for (1) .30 caliber Rifle M1903A3Provision for (7) .30 caliber Carbines M2Provision for (1) Grenade Launcher M8

AMMUNITION10 rifle grenades 12 hand grenades

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Elbow Telescope M16A1E1

Panoramic Telescope M12Gunner's Quadrant M1

Vision Devices: Direct IndirectDriver Vision cupola None

and hatchAsst. Driver Vision cupola None

and hatchVision Cupolas: (2) w/3 vision blocks on front hull plate

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry245 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max):Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Planetary gear Gear Ratio: 6.25:1Drive Sprocket: At front of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

14 individually sprung dual road wheels (7/track)Tire Size: 26 x 6 inches12 dual track return rollers (6/track)Dual compensating idler at rear of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T80E1 w/5 inch end connectorsType: (T80E1) Double pin, 23 inch widthTotal Track Width: 28 inches with end connectorsPitch: 6 inchesShoes per Vehicle: 188 (94/track)Ground Contact Length: 180 inches, average

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCMain Generator: (1) 24 volts, 50 amperes, driven by power take-off

from main engineAuxiliary Generator: (1) 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSInterphone: RC 99, 4 stationsRemote Control Equipment: RC 261FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1 1/2 quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 15 miles/hour

Short periods, level 20 miles/hourMaximum Tractive Effort: TE at stall 95,000 pounds

Per Cent of Vehicle Weight: TE/W 71.6 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 36 inchesMinimum Turning Circle: (diameter) 70 feetCruising Range: Roads approx. 50 miles

223

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240mm HOWITZER MOTOR CARRIAGE T92

224

GENERAL DATACrew: 8 menLength: Overall 382 inchesWidth: With 23 inch tracks, w/o ss 133 inches

With 28 inch tracks, w/o ss 143 inchesHeight: Overall 126.9 inchesTread: With 23 inch tracks 110 inches

With 28 inch tracks 115 inchesGround Clearance: 18.7 inchesWeight, Combat Loaded: 127,500 poundsWeight, Unstowed: estimated 123,000 poundsPower to Weight Ratio: Net 7.1 hp/ton

Gross 7.8 hp/tonGround Pressure: Zero penetration, 23" trk 15.4 psi

28" trk 12.6 psiARMORType: Rolled homogeneous steel, welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 1.0 inches 64 to 72 degreesLower 1.0 inches 40 degrees

Sides, Upper 0.5 inches 0 degreesLower 1.0 inches 0 degrees

Rear 0.5 inches 10 degreesTop 0.875 inches 90 degreesFloor 1.0 inches 90 degrees

Howitzer Shield 0.5 inches 30 degreesARMAMENTPrimary: 240mm Howitzer Ml in Mount T30 at rear of hull

Traverse: Manual 12 degrees each sideElevation: Manual +65 to 0 degreesFiring Rate: (max) 1 round/minuteLoading System: Manual

Secondary:Provision for (1) .30 caliber Rifle M1903A3Provision for (7) .30 caliber Carbines M2Provision for (1) Grenade Launcher M8

AMMUNITION10 rifle grenades 12 hand grenades

FIRE CONTROL AND VISION EQUIPMENTPrimary Weapon: Elbow Telescope M16A1E1

Panoramic Telescope M12Gunner's Quadrant Ml

Vision Devices: Direct IndirectDriver Vision cupola None

and hatchAsst. Driver Vision cupola None

and hatchVision Cupolas: (2) w/3 vision blocks on front hull plate

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement: 1100 cubic inchesBore and Stroke: 5.4 x 6 inchesCompression Ratio: 7.5:1Net Horsepower (max): 450 hp at 2600 rpmGross Horsepower (max): 500 hp at 2600 rpmNet Torque (max): 950 ft-lb at 2200 rpmGross Torque (max): 1040 ft-lb at 2200 rpmWeight: 1414 lb, dryFuel: 80 octane gasoline 245 gallonsEngine Oil: 32 quartsPOWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Planetary gear Gear Ratio: 6.25:1Drive Sprocket: At front of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

14 individually sprung dual road wheels (7/track)Tire Size: 26 x 6 inches12 dual track return rollers (6/track)Dual compensating idler at rear of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T80E1 w/5 inch end connectorsType: (T80E1) Double pin, 23 inch widthTotal Track Width: 28 inches with end connectorsPitch: 6 inchesShoes per Vehicle: 188 (94/track)Ground Contact Length: 180 inches, average

ELECTRICAL SYSTEMNominal Voltage: 24 volts DCMain Generator: (1) 24 volts, 50 amperes, driven by power take-off

from main engineAuxiliary Generator: (1) 24 volts, 50 amperes, driven by the auxiliary

engineBattery: (2) 12 volts in seriesCOMMUNICATIONSInterphone: RC 99, 4 stationsRemote Control Equipment: RC 261FIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1 1/2 quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 15 miles/hour

Short periods, level 20 miles/hourMaximum Tractive Effort: TE at stall 95,000 pounds

Per Cent of Vehicle Weight: TE/W 74.5 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 36 inchesMinimum Turning Circle: (diameter) 70 feetCruising Range: Roads approx. 50 miles

Page 221: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

CARGO CARRIER T31

GENERAL DATACrew: 6 menLength: Overall 252 inchesWidth: Over sandshields 136.3 inchesHeight: Overall 106 inchesTread: 110 inchesGround Clearance: 17.7 inchesWeight, Combat Loaded: estimated 80,000 poundsWeight, Unstowed: estimated 50,000 poundsPower to Weight Ratio: Net 11.3 hp/ton

Gross 12.5 hp/tonGround Pressure: Zero penetration 11.5 psiARMORType: Rolled homogeneous steel, welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 1.0 inches 64 degreesLower 1.0 inches 35 degrees

Sides, Upper 0.5 inches 0 degreesLower 1.0 inches 0 degrees

Rear, Upper 0.5 inches 0 degreesLower 0.5 inches 30 degrees

Top 0.5 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesARMAMENT

(1) .50 caliber MG HB M2 on ring mt. over asst. driverProvision for (1) .30 caliber Rifle M1903A3Provision for (5) .30 caliber Carbines M2Provision for (1) Grenade Launcher M8

AMMUNITION*60 rounds 8 inch howitzer 12 hand grenades600 rounds .50 caliber10 rifle grenades

VISION EQUIPMENTDirect Indirect

Driver Vision cupola Noneand hatch

Asst. Driver Vision cupola Noneand hatch

Vision Cupolas: (2) w/4 vision blocks on hull roof

*Alternate stowage arrangements for ammunition for the 240mmhowitzer, 8 inch gun, 155mm gun, or 155mm howitzer

1100 cubic inches5.4 x 6 inches7.5:1450 hp at 2600 rpm500 hp at 2600 rpm950 ft-lb at 2200 rpm1040 ft-lb at 2200 rpm1414 lb, dry200 gallons32 quarts

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement:Bore and Stroke:Compression Ratio:Net Horsepower (max):Gross Horsepower (max):Net Torque (max) :Gross Torque (max):Weight:Fuel: 80 octane gasolineEngine Oil:POWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At front of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at rear of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T81 and T80E1Type: (T81) Single pin, 24 inch width

(T80E1) Double pin, 23 inch widthPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 149.6 inches, right side

153.4 inches, left sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 75 amperes, driven by power take-off from

main engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 610 or 628 in left sponson compartmentInterphone: RC 99, 4 stationsFIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(1) 1 1/2 quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 75.0 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 36 inchesMaximum Fording Depth: 36 inchesMinimum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 100 miles

225

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TANK RECOVERY VEHICLE T12

226

GENERAL DATACrew: 6 menLength: Boom to rear, travel position 298 inchesLength: Without boom 263 inchesBoom Overhang: Boom to rear 35 inchesWidth: Over sandshields 148 inchesHeight: Boom in travel position 134 inchesTread:-With 23 inch tracks 110 inches

With 28 inch tracks 115 inchesGround Clearance : 18 inchesWeight, Combat'Loaded: estimated 90,000 poundsWeight, Unstowed: estimated 80,000 poundsPower to Weight Ratio: Net 10.0 hp/ton

Gross 11.1 hp/tonGround Pressure: Zero penetration, 23" trk 12.7 psi

28" trk 10.5 psiARMORType: Turret, rolled homogeneous steel; Hull, rolled and cast homo-

geneous steel; Welded assemblyHull Thickness: Actual Angle w/Vertical

Front, Upper 4.0 inches 46 degreesLower 3.0 inches 53 degrees

Sides, Front 3.0 inches 0 degreesRear 2.0 inches 0 degrees

Rear, Upper 2.0 inches 10 degreesLower 0.75 inches 62 degrees

Top 0.875 inches 90 degreesFloor, Front 1.0 inches 90 degrees

Rear 0.5 inches 90 degreesTurret Thickness:

Front 1.25 inches 0 degreesSides 1.25 inches 0 degreesRear 1.25 inches 0 degreesTop 1.0 inches 90 degrees

ARMAMENT(1) .50 caliber MG HB M2 on ring mount on turret top(1) .30 caliber MG M1919A4 in bow mountProvision for (2) .45 caliber SMG M3Provision for (4) .30 caliber Carbines M2Provision for (1) 2.36 inch Rocket Launcher M9A1Provision for (1) Grenade Launcher M8

AMMUNITION550 rounds .50 caliber 10 rockets 2.36 inch360 rounds .45 caliber 10 rifle grenades2000 rounds .30 caliber 12 hand grenades

VISION EQUIPMENTDirect Indirect

Driver Hatch Periscope M6 (2)Asst. Driver Hatch Periscope M6 (2)Commander Vision cupola Periscope M6 (1)

and hatchTotal Periscopes: M6 (5)Vision Cupolas: (1) w/6 vision blocks on turret top

ENGINEMake and Model: Ford GAFType: 8 cylinder, 4 cycle, 60 degree veeCooling System: Liquid Ignition: MagnetoDisplacement: 1100 cubic inchesBore and Stroke: 5.4 x 6 inchesCompression Ratio: 7.5:1Net Horsepower (max): 450 hp at 2600 rpmGross Horsepower (max): 500 hp at 2600 rpmNet Torque (max) : 950 ft-lb at 2200 rpmGross Torque (max): 1040 ft-lb at 2200 rpmWeight: 1414 lb, dryFuel: 80 octane gasoline 202 gallonsEngine Oil: 32 quartsPOWER TRAINTransfer Case: Planetary reduction gears

Gear Ratio: 1.377:1 engine to transmissionTransmission: Torqmatic, 3 speeds forward, 1 reverse

Torque Converter Ratio: Varies from 1:1 to 4.8:1Gear Ratios: 1st 1:1 3rd 0.244:1

2nd 0.428:1 reverse 0.756:1Steering: Controlled differential

Bevel Gear Ratio: 3.53:1 Steering Ratio: 1.79:1Brakes: Mechanical, 3 shoe, reverse anchorFinal Drive: Spur gear Gear Ratio: 3.95:1Drive Sprocket: At rear of vehicle with 13 teeth

Pitch Diameter: 25.068 inchesRUNNING GEARSuspension: Torsion bar

12 individually sprung dual road wheels (6/track)Tire Size: 26 x 6 inches10 dual track return rollers (5/track)Dual compensating idler at front of each trackIdler Tire Size: 26 x 6 inchesShock absorbers fitted on first 2 and last 2 road wheels on each side

Tracks: Center guide, T80E1 w/5 inch end connectorsType: (T80E1) Double pin, 23 inch widthTotal Track Width: 28 inches with end connectorsPitch: 6 inchesShoes per Vehicle: 164 (82/track)Ground Contact Length: 151.5 inches, left side

155.5 inches, right sideELECTRICAL SYSTEMNominal Voltage: 24 volts DCGenerator: (1) 24 volts, 150 amperes, belt driven by either the main

engine or the auxiliary engineBattery: (2) 12 volts in seriesCOMMUNICATIONSRadio: SCR 508 or 528 on shelf in turretInterphone: (part of radio) 5 stations plus RC 298 external interphone

extensionFlag Set M238, Panel Set AP50A, SpotlightFIRE AND GAS PROTECTION

(2) 10 pound carbon dioxide, fixed(2) 4 pound carbon dioxide, portable(2) 1 quart carbon tetrachloride, portable(1) 1 1/2 quart decontaminating apparatus

PERFORMANCEMaximum Speed: Sustained, level road 25 miles/hour

Short periods, level 30 miles/hourMaximum Tractive Effort: TE at stall 60,000 pounds

Per Cent of Vehicle Weight: TE/W 66.7 per centMaximum Grade: 60 per centMaximum Trench: 8 feetMaximum Vertical Wall: 46 inchesMaximum Fording Depth: 48 inchesMinimum Turning Circle: (diameter) 60 feetCruising Range: Roads approx. 100 miles

Page 223: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

WEAPON DATA SHEETS

The general characteristics and performance datafor the major armament mounted on the T20 seriesvehicles are included in the following pages. To avoidconfusion, caliber lengths are quoted for each weaponusing both the U.S. (bore length only) and the Ger-man method (muzzle to rear face of breech). Otherdimensions are defined in the sketch below.

Official nomenclature in effect during the periodof greatest service is used to describe each type ofammunition. Since the terminalogy changed occasion-ally, a standard nomenclature is added in parenthesis.An explanation of the standard terms, which are usedseparately and in combination, is given below:

AP Armor piercing, uncappedAPBC Armor piercing with ballistic cap, with-

out armor piercing capAPCBC Armor piercing with armor piercing

cap and ballistic capAPCR Armor piercing, composite rigidCP Concrete piercingHE High explosiveHEAT High explosive antitank, hollow charge-T Tracer

All armor plate angles quoted in the data sheetsare measured between a vertical plane and the platesurface. This is illustrated by angle a in the figurebelow. The armor plate penetration performance ofthe various projectiles is usually quoted for a 30degree angle of obliquity. This angle is defined as theangle between a line perpendicular to the armor plateand the projectile path. This is shown by angle ßbelow.

In regard to armor penetration, it should benoted that the values obtained at 30 degrees obliquitydo not necessarily indicate the relative performanceof these projectiles at other angles. For example, the90 mm AP T33 is approximately equal to the APCM82 at 30 degrees, but at the 55 degree angle of thePanther's front plate, the latter fails completely whilethe T33 will penetrate at ranges up to 1100 yards.Against this type of high obliquity target, the mono-bloc shot was also much more effective than theHVAP or APCR type projectile.

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75mm Gun M3

Carriage and Mount

Length of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Muzzle Brake, etc.Overall LengthDiameter of BoreChamber CapacityWeight, TubeTotal WeightType of Breechblock

RiflingAmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)

Penetration Performance

APC M61

AP M72

APC M61

AP M72

Range

Range

Medium Tank M3 series in Mount Ml, Medium Tank M4 series in Mounts M34 and M34A1,Medium Tank M7 in Mount M47, Medium Tank T22E1 in Mount M34 with an automatic loader,Assault Tank T14 in Mount M34A114.4 inches96.2 inches12.96 inches (APC M61), 11.5 inches (HE M48)97.67 inches (APC M61), 99.1 inches (HE M48)110.63 inches, 37.5 calibers7,75 inches118.38 inches, 40.1 calibersNone118.38 inches2.95 inches88.05 cubic inches (APC M61), 80.57 cubic inches (HE M48)611 pounds893 poundsSemiautomatic sliding wedge. Gun mounted so breechblock slides vertically in Mount Ml, at 45degrees in Mount M47, and horizontally in Mounts M34 and M34A124 grooves, uniform right-hand twist, one turn in 25.59 calibers (slope 7 degrees)FixedPercussionAPC M61 Projectile (APCBC/HE-T) 19.92 poundsAP M72 Shot (AP-T) 18.80 poundsHE M48 Shell (HE), Supercharge 19.56 poundsHE M48 Shell (HE), Normal 18.80 poundsHC BI M89 Shell, Smoke 9.83 poundsAPC M61 Projectile (APCBC/HE-T) 14.96 poundsAP M72 Shot (AP-T) 13.94 poundsHE M48 Shell (HE) 14.70 poundsHC BI M89 Shell, Smoke 6.61 pounds38,000 psi20 rounds/minuteAPC M61 Projectile (APCBC/HE-T) 2,030 ft/secAP M72 Shot (AP-T) 2,030 ft/secHE M48 Shell (HE), Supercharge 1,980 ft/secHE M48 Shell (HE), Normal 1,520 ft/secHC BI M89 Shell, Smoke 850 ft/secAPC M61 Projectile (APCBC/HE-T) 427 ft-tonsAP M72 Shot (AP-T) 398 ft-tonsHE M48 Shell (HE), Supercharge 400 ft-tonsHE M48 Shell (HE), Normal 235 ft-tonsAPC M61 Projectile (APCBC/HE-T) 14,000 yardsAP M72 Shot (AP-T) 10,650 yardsHE M48 Shell (HE), Supercharge 14,000 yardsHE M48 Shell (HE), Normal 11,400 yardsHC BI M89 Shell, Smoke approx. 1,500 yardsHomogeneous Armor at 30 degrees obliquity500 yards 1,000 yards 1,500 yards2.6 inches(66mm)3.0 inches(76mm)

2.4 inches(60mm)2.5 inches(63mm)

Face-Hardened Armor at 30 degrees obliquity500 yards 1,000 yards2.9 inches 2.6 inches(74mm) (67mm)2.6 inches 2.1 inches(66mm) (5 3mm)

2.2 inches(55mm)2.0 inches(51mm)

1,500 yards2.4 inches(60mm)1.6 inches(41mm)

2,000 yards2.0 inches(50mm)1.7 inches(43mm)

2,000 yards2.1 inches(54mm)1.3 inches(33mm)

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Carriage and Mount

Length of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Muzzle Brake, etc.Overall LengthDiameter of BoreChamber CapacityWeight, Tube (without muzzle brake)Weight, Complete (without muzzle brake)Weight, Muzzle Brake M2Total WeightType of Breechblock

Rifling

AmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)

RangePenetration Performance

APC M62

HVAP M93

AP M79

Penetration values are for the M1A1 gun. A

76mm Gun M1, M1A1, M1A1C, and M1A2

Medium Tank M4 series in Mount M62, Medium Tanks T20, T20E3, T22, and T23-2 in Mount T79,Medium Tanks T23 and T23E3 in Mount T80, Motor Carriages M18, T86, and T86E1 in Mount M122.46 inches133.54 inches20.7 inches (square base projectiles)135.3 inches (square base projectiles)156.00 inches, 52.0 calibers7.75 inches163.75 inches, 54.6 calibers11.6 inches, Muzzle Brake M2 on M1A1C and M1A2163.75 inches (Ml, MlAl), 175.4 inches (M1A1C, M1A2)3.000 inches142.6 cubic inches (APC M62), 140.50 inches (HE M42A1)870 pounds (M1), 940 pounds (M1A1)1,141 pounds (M1), 1,206 pounds (M1A1C), 1,231 pounds (M1A2)62 pounds1,141 pounds (M1), 1,268 pounds (M1A1C), 1,293 pounds (M1A2)Semiautomatic sliding wedge. Gun mounted so breechblock slides horizontally in Mounts M62,T79, and T80, and at 45 degrees in Mount Ml28 grooves, uniform right-hand twist, one turn in 40 calibers (M1, M1A1, M1A1C) or 32 calibers(M1A2)FixedPercussionAPC M62 Projectile (APCBC/HE-T) 24.80 poundsHVAP M93 Shot (APCR-T) 18.91 poundsAP M79 Shot (AP-T) 24.24 poundsHE M42A1 Shell (HE) 22.23 poundsHC BI M88 Shell, Smoke 13.43 poundsAPC M62 Projectile (APCBC/HE-T) 15.44 poundsHVAP M93 Shot (APCR-T) 9.40 poundsAP M79 Shot (AP-T) 15.00 poundsHE M42A1 Shell (HE) 12.87 poundsHC BI M88 Shell, Smoke 7.38 pounds43,000 psi20 rounds/minuteAPC M62 Projectile (APCBC/HE-T) 2,600 ft/secHVAP M93 Shot (APCR-T) 3,400 ft/secAP M79 Shot (AP-T) 2,600 ft/secHE M42A1 Shell (HE) 2,700 ft/secHC BI M88 Shell, Smoke 900 ft/secAPC M62 Projectile (APCBC/HE-T) 724 ft-tonsHVAP M93 Shot (APCR-T) 7 5 3 ft-tonsAP M79 Shot (AP-T) 703 ft-tonsHE M42A1 Shell (HE) 650 ft-tonsAPC M62 Projectile (APCBC/HE-T) 16,100 yardsHVAP M93 Shot (APCR-T) 13,100 yardsAP M79 Shot (AP-T) 12,770 yardsHE M42A1 Shell (HE) 14,200 yardsHC BI M88 Shell, Smoke (at 12 degrees) 2,000 yardsHomogeneous Armor at 30 degrees obliquity500 yards 1,000 yards 1,500 yards 2,000 yards3.7 inches 3.5 inches 3.2 inches 3.0 inches(93mm) (88mm) (82mm) (75mm)6.2 inches 5.3 inches 4.6 inches 3.9 inches(157mm) (135mm) (116mm) (98mm)4.3 inches 3.6 inches 3.0 inches 2.5 inches(109mm) (92mm) (76mm) (64mm)

slight increase for APC is obtained with the M1A2 at the longer ranges

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90mm Gun M3

Carriage and Mount

Length of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Muzzle Brake, etc.Overall LengthDiameter of BoreChamber CapacityWeight, Complete (without muzzle brake)Weight, Muzzle Brake M3Total WeightType of BreechblockRiflingAmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)

Penetration PerformanceRange

APC M82 (2,650)

APC M82 (2,800)

HVAP M304 (T30E16)

AP T33

Medium Tanks T25 and T25E1 in Mount T99, Medium Tanks T26 and T26E1 in Mount T99E1,Medium Tanks M26 (T26E3), M26E2, and T26E5 in Mount M67 (T99E2), Motor Carriage M36series in Mount M4 (T8). This weapon mounted experimentally in the Heavy Tank T1E1 andMotor Carriages M10 and M1824.8 inches152.4 inches20.8 inches (boat-tailed projectiles)156.4 inches (boat-tailed projectiles)177.15 inches, 50.0 calibers9.00 inches186.15 inches, 52.5 calibers16.0 inches, Muzzle Brake M3 on late production202.2 inches with muzzle brake3.543 inches300 cubic inches2,300 pounds149.5 pounds2,450 poundsSemiautomatic, vertical sliding wedge32 grooves, uniform right-hand twist, one turn in 32 calibersFixedPercussionAPC M82 Projectile (APCBC/HE-T) early 42.75 poundsAPC M82 Projectile (APCBC/HE-T) late 43.87 poundsHVAP T30E16 Shot (APCR-T) 37.13 poundsAP T33 Shot (APBC-T) 43.82 poundsHE M71 Shell (HE) 41.93 poundsAPC M82 Projectile (APCBC/HE-T) 24.11 poundsHVAP M304 (T30E16) Shot (APCR-T) 16.80 poundsAP T33 Shot (APBC-T) 24.06 poundsHE M71 Shell (HE) 23.29 pounds38,000 psi8 rounds/minuteAPC M82 Projectile (APCBC/HE-T) early 2,650 ft/secAPC M82 Projectile (APCBC/HE-T) late 2,800 ft/secHVAP M304 (T30E16) Shot (APCR-T) 3,350 ft/secAP T33 Shot (APBC-T) 2,800 ft/secHE M71 Shell (HE) 2,700 ft/secAPC M82 Projectile (APCBC/HE-T) early 1,174 ft-tonsAPC M82 Projectile (APCBC/HE-T) late 1,310 ft-tonsHVAP M304 (T30E16) Shot (APCR-T) 1,307 ft-tonsAP T33 Shot (APBC-T) 1,310 ft-tonsHE M71 Shell (HE) 1,177 ft-tonsAPC M82 Projectile (APCBC/HE-T) early 20,400 yardsAPC M82 Projectile (APCBC/HE-T) late 21,400 yardsHVAP M304 (T30E16) Shot (APCR-T) 15,700 yardsAP T33 Shot (APBC-T) 21,000 yardsHE M71 Shell (HE) 19,560 yardsHomogeneous Armor at 30 degrees obliquity500 yards 1,000 yards 1,500 yards 2,000 yards4.7 inches 4.4 inches 4.1 inches 3.8 inches(120mm) (112mm) (104mm) (96mm)5.1 inches 4.8 inches 4.5 inches 4.2 inches(129mm) (122mm) (114mm) (106mm)8.7 inches 7.9 inches 7.0 inches 6.1 inches(221 mm) (199mm) (176mm) (156mm)4.7 inches 4.6 inches 4.5 inches 4.3 inches(119mm) (117mm) (114mm) (109mm)

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Carnage and MountLength of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Muzzle Brake, etc.Overall LengthDiameter of BoreChamber CapacityWeight, Complete (without muzzle brake)Weight, Muzzle Brake M3Total WeightType of BreechblockRiflingAmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)Penetration Performance

RangeAP T43

HVAP T44

90mmGun T15E2

Medium Tank T26E4 in Mount T119, Heavy Tanks T32 and T32E1 in Mount T11940.7 inches207.2 inches36.7 inches (boat-tailed projectiles)211.2 inches (boat-tailed projectiles)247.9 inches, 70.0 calibers9.0 inches256.9 inches, 72.6 calibers16.0 inches, Muzzle Brake M3272.9 inches3.543 inches488 cubic inches (estimated)3,270 pounds150 pounds3,420 poundsSemiautomatic, vertical sliding wedge32 grooves, uniform right-hand twist, one turn in 32 calibersSeparatedPercussionAP T43 Shot (APBC-T)HVAP T44 Shot (APCR-T)HE T42 Shell (HE)AP T43 Shot (APBC-T)HVAP T44 Shot (APCR-T)HE T42 Shell (HE)41,500 psi4 rounds/minuteAP T43 Shot (APBC-T)HVAP T44 Shot (APCR-T)HE T42 Shell (HE)AP T43 Shot (APBC-T)HVAP T44 Shot (APCR-T)HE T42 Shell (HE)

51.2 pounds44 pounds50.4 pounds24.06 pounds16.70 pounds23.3 pounds

HE T42 Shell (HE)Homogeneous Armor at 30 degrees obliquity500 yards 1,000 yards 1,500 yards5.2 inches 5.0 inches 4.9 inches(132mm) (127mm) (124mm)9.6 inches 8.7 inches 7.7 inches(244mm) (221mm) (196mm)

3,200 ft/sec3,750 ft/sec3,200 ft/sec1,711 ft-tons1,628 ft-tons1,654 ft-tons

27,000 yards

2,000 yards4.8 inches(122mm)

6.8 inches(173mm)

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90mm Gun T54

Carriage and MountLength of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Muzzle Brake, etc.Overall LengthDiameter of BoreChamber CapacityWeight, Complete (without muzzle brake)Weight, Muzzle BrakeTotal WeightType of BreechblockRiflingAmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)Penetration Performance

RangeAP

HVAP

Medium Tank M26E1 in Mount T12624.6 inches209.184 inches21.8 inches212 inches233.8 inches, 66.6 calibers8.45 inches242.25 inches, 68.4 calibers6.75 inches, Muzzle Brake M3E2249.0 inches3.543 inches465 cubic inches3,400 pounds80 pounds3,480 poundsSemiautomatic, vertical sliding wedge32 grooves, uniform right-hand twist, one turn in 32 calibersFixedPercussionAP Shot (APBC-T)HVAP Shot (APCR-T)HE Shell (HE)AP Shot (APBC-T)HVAP Shot (APCR-T)HE Shell (HE)40,000 psi6 rounds/minuteAP Shot (APBC-T)HVAP Shot (APCR-T)HE Shell (HE)AP Shot (APBC-T)HVAP Shot (APCR-T)HE Shell (HE)

HE Shell (HE)Homogeneous Armor at 30 degrees obliquity500 yards 1,000 yards 1,500 yards5.2 inches 5.0 inches 4.9 inches(132mm) (127mm) (124mm)9.6 inches 8.7 inches 7.7 inches(244mm) (221mm) (196mm)

approx.approx.approx.

49424824.116.723.3

poundspoundspoundspoundspoundspounds

3,200 ft/sec3,750 ft/sec3,200 ft/sec1,711 ft-tons1,628 ft-tons1,654 ft-tons

27,000 yards

2,000 yards4.8 inches(122mm)

6.8 inches(173mm)

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Carriage and Mount

Length of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Muzzle Brake, etc.Overall LengthDiameter of BoreChamber CapacityWeight, TubeTotal WeightType of BreechblockRiflingAmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)

Penetration Performance

105mm Howitzer M4

Medium Tank M4 series in Mount M52, Medium Tank M45 (T26E2) in Mount M71 (T117), MotorCarriage M37 in Mount M515.03 inches78.02 inches11.38 inches (boat-tailed projectiles)81.67 inches (boat-tailed projectiles)93.05 inches, 22.5 calibers8.25 inches101.3 inches, 24.5 calibersNone101.3 inches4.134 inches153.80 cubic inches973 pounds1,140 poundsManually operated, horizontal sliding wedge36 grooves, uniform right-hand twist, one turn in 20 calibersSemifixed, variable charge except for HEAT M67PercussionHE M1 Shell (HE) 42.07 poundsHEAT M67 Shell (HEAT-T) 36.85 poundsWP M60 Shell, Smoke 43.77 poundsHC BE M84 Shell, Smoke 41.94 poundsHE M1 Shell (HE) 33.00 poundsHEAT M67 Shell (HEAT-T) 29.22 poundsWP M60 Shell, Smoke 34.31 poundsHC BE M84 Shell, Smoke 32.87 pounds28,000 psi8 rounds/minuteHE M1 Shell (HE) maximum charge 1,550 ft/secHEAT M67 Shell (HEAT-T) 1,250 ft/secWP M60 Shell, Smoke maximum charge 1,550 ft/secHC BE M84 Shell, Smoke maximum charge 1,550 ft/secHE M1 Shell (HE) maximum charge 555 ft-tonsHEAT M67 Shell (HEAT-T) 317 ft-tons

HE M1 Shell (HE) maximum charge 12,205 yardsHEAT M67 Shell (HEAT-T) 8,590 yardsWP M60 Shell, Smoke maximum charge 12,150 yardsHC BE M84 Shell, Smoke maximum charge 12,205 yardsHomogeneous Armor at 0 degrees obliquity, HEAT M67, 4.0 inches at any range

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Carriage and MountLength of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Breech MechanismOverall LengthDiameter of BoreChamber CapacityTotal WeightType of BreechblockRiflingAmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energey is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)

Penetration Performance

8 inch Howitzer M1 and M2

Towed Carriage Ml, Motor Carriage T84, Motor Carriage M43 in Mount M1735.2 inches164.8 inches26.2 inches (HE M106)173.83 inches (HE M106)200.0 inches, 25.0 calibers9.6 inches209.59 inches, 26.2 calibers6.4 inches216.0 inches8.00 inches1,527 cubic inches (HE M106)10,240 poundsStepped thread interrupted screw, horizontal swing64 grooves, uniform right-hand twist, one turn in 25 calibersSeparate LoadingPercussionHE M106 Shell (HE) with Charge M2HE Mk1A1 Shell (HE) with Charge M1HE M106 Shell (HE)HE Mk1A1 Shell (HE)33,000 psi1 round/minuteHE M106 Shell (HE) with Charge M2HE Mk1A1 Shell (HE) with Charge M1HE Ml06 Shell (HE) with Charge M2

228.19 pounds213.19 pounds200.00 pounds200.00 pounds

1,950 ft/sec1,339 ft/sec5,272 ft-tons

HE M106 Shell (HE) with Charge M2 18,510 yardsHE Mk1A1 Shell (HE) with Charge M1 11,170 yardsReinforced Concrete at 0 degrees obliquity, HE M106 with CP Fuse M78; 5.5 feet at 1,000 yards,4.7 feet at 3,000 yards, 4.0 feet at 5,000 yards, 3.2 feet at 10,000 yards, 3.1 feet at 15,000 yards

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Carriage and MountLength of Chamber (to rifling)Length of RiflingLength of Chamber (to projectile base)Travel of Projectile in BoreLength of BoreDepth of Breech RecessLength, Muzzle to Rear Face of BreechAdditional Length, Breech MechanismOverall LengthDiameter of BoreChamber CapacityTotal WeightType of BreechblockRiflingAmmunitionPrimerWeight, Complete Round

Weight, Projectile

Maximum Powder PressureMaximum Rate of FireMuzzle Velocity

Muzzle Energy of Projectile, KE= 1/2 MV2

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount)

Penetration Performance

8 inch Gun M1

Towed Carriage M2, Motor Carriage T93 in Mount T3171.8 inches328.15 inches61.4 inches (HE M103)338.58 inches (HE M103)400.0 inches, 50.0 calibers9.5 inches409.5 inches, 51.2 calibers5.0 inches (estimated)415 inches (estimated)8.00 inches5,156 cubic inches (HE M103)29,800 poundsStepped thread interrupted screw, vertical swing64 grooves, uniform right-hand twist, one turn in 25 calibersSeparate LoadingPercussionHE M103 Shell (HE) maximum chargeMk14 Projectile, Common (APBC/HE) max. chg.HE M103 Shell (HE)Mk14 Projectile, Common (APBC/HE)38,000 psi1 round/minuteHE M103 Shell (HE) maximum chargeMk14 Projectile, Common (APBC/HE) max. chg.HE M103 Shell (HE) maximum charge

346 pounds366 pounds240 pounds260 pounds

2,850 ft/sec2,750 ft/sec

13,514 ft-tons

HE M103 Shell (HE) maximum charge 35,630 yardsMk14 Projectile, Common (APBC/HE) max. chg. 32,500 yardsReinforced Concrete at 0 degrees obliquity, HE M103 with CP Fuse M78; 5.2 feet at 15,000yards, 4.5 feet at 19,000 yards, 3.8 feet at 23,000 yards, 3.7 feet at 27,000 yards

235

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240mm Howitzer M1

Carriage and Mount Towed Carriage M1, Motor Carriage T92 in Mount T30Length of Chamber (to rifling) 63.8 inchesLength of Rifling 257.69 inchesLength of Chamber (to projectile base) 53.3 inches (HE M114)Travel of Projectile in Bore 268.16 inches (HE M114)Length of Bore 321.5 inches, 34.0 calibersDepth of Breech Recess 9.5 inchesLength, Muzzle to Rear Face of Breech 331.0 inches, 35.0 calibersAdditional Length, Breech Mechanism 5.0 inches (estimated)Overall Length 336 inches (estimated)Diameter of Bore 9.45 inchesChamber Capacity 4,430.0 cubic inches (HE M114)Total Weight 25,100 poundsType of Breechblock Stepped thread interrupted screw, vertical swingRifling 68 grooves, uniform right-hand twist, one turn in 25 calibersAmmunition Separate LoadingPrimer PercussionWeight, Complete Round HE M114 Shell (HE) maximum charge 438.78 poundsWeight, Projectile HE M114 Shell (HE) 360 poundsMaximum Powder Pressure 36,000 psiMaximum Rate of Fire 1 round/minuteMuzzle Velocity HE M114 Shell (HE) maximum charge 2,300 ft/secMuzzle Energy of Projectile, KE= 1/2 MV2 HE M114 Shell (HE) maximum charge 13,202 ft-tons

Rotational energy is neglected andvalues are based on long tons (2,240pounds)

Maximum Range (independent of mount) HE M114 Shell (HE) maximum charge 25,255 yardsPenetration Performance Reinforced Concrete at 0 degrees obliquity, HE Ml 14 with CP Fuse M78; 4.9 feet at 12,500

yards, 4.4 feet at 15,000 yards, 4.1 feet at 19,000 yards

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REFERENCES AND SELECTED BIBLIOGRAPHY

Books and Manuscripts

Hechler, Ken, "The Bridge at Remagen," Ballantine Books, New York,New York, 1957

. , "Spearhead in the West," The History of the ThirdArmored Division 1941-1945

Green, Constance McL., Harry C. Thompson, and Peter C. Roots, "TheOrdnance Department: Planning Munitions for War," The U.S.Army in World War II, Office of the Chief of Military History,Washington D.C., 1955

Thomson, Harry C. and Lidâ Mayo, "The Ordnance Department: Pro-curement and Supply," The U.S. Army in World War II, Office ofthe Chief of Military .History, Washington D.C., 1960

Mayo, Lidà, "The Ordnance Department on Beachhead and Battle-front," The U.S. Army in World War II, Office of the Chief ofMilitary History, Washington D.C., 1968

Chase, Daniel, "A History of Combat Vehicle Development," un-published manuscript

Whiting, T. E., "Statistics," Manuscript prepared for the History of theU.S. Army in World War II, Office of the Chief of Military History,Washington D.C., 9 April 1952

Appleman, Roy E., "South to the Naktong, North to the Yalu," TheU.S. Army in the Korean War, Office of the Chief of MilitaryHistory, Washington D.C., 1961

Reports and Official Documents

"Summary of Combat Vehicle Development," Office Chief of Ord-nance, Detroit, 1945

"The Design, Development, and Production of Tanks in World War II,"Office Chief of Ordnance, Washington D.C., 15 August 1944

"Record of Army Ordnance Research and Development—Tanks," OCO,Washington D.C., undated

"Catalogue of Standard Ordnance Items-Tanks and AutomotiveVehicles," OCO, Washington D.C., Revised to June 1945

"A Handbook of Ordnance Automotive Engineering-Volume 1, Com-bat and Tracklaying Vehicles," Aberdeen Proving Ground, Mary-land, 1 May 1945

"Report of the Fiscal Year 1944-1945, Research and DevelopmentService," OCO, Washington D.C., October 1945

"New Ordnance Materiel," OCO, Washington D.C., January 1945"Pacific Area Materiel," OCO, Washington D.C., July 1945"Notes on Materiel, Medium Tanks T20 and T20E3," Fisher Body

Division, General Motors Corporation, Detroit Michigan, undated"Notes on Materiel, Medium Tank T22," Chrysler Corporation Detroit,

Michigan, undated"First Report on Automatic 75 mm gun in Medium Tank T22E1 and

First Report on Ordnance Program No. 5738," APG, Maryland, 2April 1945

"Preliminary Specification RY-24184, T23 Medium Tank built by ErieWorks," General Electric Company, Schenectady, N.Y., March 1943

"Final report on the Ten Production Models Medium Tank T23, ProjectNo. P-417-1," The Armored Board, Fort Knox, Kentucky, 4November 1944

"Pilot Tank T23E3 with Torsion Bar Suspension, Report No.T-61505.38-01," Chrysler Engineering Division, Detroit, Michigan,14 November 1944

"Final Report of Test of Three Medium Tanks T23 with 23 inch trackand horizontal volute spring suspension, Report No. P659," TheArmored Board, Fort Knox, Kentucky, 27 August 1945

"Technical Manual TM9-734, Medium Tank T23," War Department,Washington D.C., 24 March 1944

"Pilot Tanks, T25 Medium Tanks Equipped with 90 mm Gun, ReportNo. T-61505-01," Chrysler Engineering Division, Detroit, Michigan,23 June 1944

"Final Report of Test of Medium Tank T25, Project No. P-595," TheArmored Board, Fort Knox, Kentucky, 14 August 1945

"Final Report of Test of Medium Tank T25E1, Project No. P-545,"The Armored Board, Fort Knox, Kentucky, 17 March 1945

"Notes on Materiel, Medium Tanks T25E1 and T26E1," War Depart-ment, Washington D.C., June 1944

"Notes on Materiel, 90 mm Combination Gun Mount T102," RockIsland Arsenal, June 1945

"T26 Heavy Tank Pilot Vehicle, Report No. T-61905.8," ChryslerEngineering Division, Detroit, Michigan, 4 May 1945

"Final Report on Comparative Test of Heavy Tank T26 and HeavyTank T26E1, Project No. P-636," The Armored Board, Fort Knox,Kentucky, 28 September 1945

"First Report on Test of Heavy Tank T26E1 and First Report onOrdnance Program 6004," APG, Maryland, 26 May 1944

"Final Report on Test of Heavy Tank T26E3, Project No. P-546-1,"The Armored Board, Fort Knox, Kentucky, 9 May 1945

"Technical Manual TM9-735, Heavy Tank T26E3," War Department,Washington D.C., 15 January 1945

"Technical Manual TM9-735, Medium Tanks M26 and M45," WarDepartment, Washington D.C., August 1948

"Technical Manual TM9-1735A, Medium Tanks M26 and M45, PowerTrains," War Department, Washington D.C., September 1947

"Technical Manual TM9-1735B, Medium Tanks M26 and M45, Tracks,Suspension, Hull, and Turret," War Department, Washington D.C.,September 1947

"First Report on Medium Tank T26E4 and Seventeenth Report onOrdnance Program 6009," APG, Maryland, 14 February 1947

"First Report on Test of Medium Tank T26E5 and Twelfth Report onOrdnance Program No. 6009," APG, Maryland, 22 July 1946

"Test of 90 mm Combination Gun Mount T126 in Medium TankM26E1, First Report on Project TT2-6-34," APG, Maryland, 15April 1949

"First Partial Report on Pilot Model Test of Medium Tank M26E2 andMedium Tank T40 and Second Report on Project TT2-668," APG,Maryland, 27 June 1950

"Notes on Materiel, Multiple Rocket Launcher, 4.5 inch T99," ChryslerCorporation, Detroit, Michigan, 15 November 1945

"Notes on Materiel, Eight Inch Howitzer Motor Carriage T84," ChryslerEngineering Division, Detroit, Michigan, undated

"Notes on Materiel, Eight Inch Gun Motor Carriage T93," ChryslerCorporation, Detroit, Michigan, 15 August 1945

"Notes on Materiel, 240 mm Howitzer Motor Carriage T92," ChryslerCorporation, Detroit, Michigan, 15 July 1945

"Notes on Materiel, Eight Inch Gun Motor Carriage T93," ChryslerCorporation, Detroit, Michigan, 15 August 1945

"Notes on Materiel, 240 mm Howitzer Motor Carriage T92," ChryslerCorporation, Detroit, Michigan, 15 July 1945

"Test of 240 mm Howitzer Motor Carriage T92 and First Report onProject TT2-538," APG, Maryland, 3 May 1949

"Notes on Materiel, Cargo Carrier T31," Chrysler Engineering Division,Detroit, Michigan, undated

"Notes on Materiel, Tank Recovery Vehicle T12," Pressed Steel CarCompany, Inc., Chicago, Illinois, 1 December 1945

"Three M26 tanks at Chinju 31 July 1950," Inspector General Report,10 September 1950

"The Employment of Armor in Korea, Vol. I," The Armor School,Fort Knox, Kentucky 1952

"Summary of Activities," 2nd Battalion 27th Infantry, 21-22nd August1950

"Technical Manual TM9-1901, Artillery Ammunition," War Depart-ment, Washington D.C., 29 June 1944 and Department of theArmy, September 1950

"Technical Manual TM9-1907, Ballistic Performance Data of Ammuni-tion," Department of the Army, Washington D.C., July 1948

238

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INDEX

Ammunition37 mm, 15375 mm, 153, 22876 mm, 153, 22990 mm, for M3 gun, 20-21, 25, 27, 39,

98, 120-121, 127, 140, 153, 199-200,230for T15 gun, 28, 140for T15E2 gun, 140, 145, 231forT54gun, 150, 153, 232

105 mm, 139, 2338 inch, for howitzer Ml, 161, 234

for gun Ml, 235240 mm, 236

Antitank GunsGerman, 23Japanese, 47 mm, 41Soviet, 57 mm, 192

Antwerp, Belgium, 13, 14, 34Armies, U.S.

Fkst, 13-26Ninth, 34Tenth, 44Third, 38

Armored Board, Fort Knox, Ky., 13, 82, 88,, 92,94,97,100,101,104,107,117,

121, 136, 143, 149Armored Divisions, U.S.

2nd, 343rd, 12-285th, 349th, 9-13, 16-25llth, 38

Armored Infantry, U.S.27th, Co. A, 9-12

Armored Regiments, U.S.32nd, Co. D, 17, 2532nd, Co. E, 17,2532nd, Co. G, 17,2532nd, Co. H, 1732nd, Co. I, 1733rd, Co. D, 1733rd, Co. E, 17,2033rd, Co. F, 17-1833rd, Co. H, 17, 2233rd, Co. I, 17, 22

Army Groups, U.S., 12th, 13Assignment of Tanks, Zebra Mission, 17Barnes, Major General G.M., 13, 14, 43, 49Borden, Brigadier General William A., 41Bore sighting, 16, 17"Bowling Alley" in Korea, 184-185Bradley, General Omar, 13, 14Brosha, 1st Lt. William, 5Cargo Carriers

T25, 158T31, 162-163, 165, 225

Chinju, Korea, 178, 191Colby, Colonel Joseph, 13, 14, 43, 49Cologne, Germany, 20-25

action in front of Cathedral, 25Cross drive transmission, 58, 154Day, Johnny, 5Dean, Colonel George, 13Divisions, North Korean

105th Armored, 1757th Infantry, 1754th Infantry, 182

239

Howitzer Motor Carriages, see MotorCarriages

Jarrett, Colonel G.B., 30Key, Sergeant Chester, 10, 22Le Havre, Fiance, 34MacArthur, General of the Army Douglas,

180Marine Provisional Brigade, 1st, 182Marshall, General of the Army George C., 13Maxwell, Major General Russell, 13Motor Carriages

T79, 155 mm gun, 158T80, 8 inch howitzer, 158T84, 8 inch howitzer, 159-161, 222T92, 240 mm howitzer, 164-169, 224T93, 8 inch gun 164-169, 223

Mott, 1st Lt. Hugh B., 11München Gladbach, Germany, 34Munson, 1st Lt. Max, 5Okinawa Mission, 41-46Ordnance Battalions, U.S.

310th, 20Ordnance Companies U.S.

81st Heavy Maintainance Tank Co., 44293rd Heavy Maintainance Tank Co., 44536th Heavy Maintainance Tank Co., 34559th Heavy Maintainance Tank Co., 14

Panther, German PzKpfw V, 25, 194, 199-202at Cologne, 25compared with Pershing, 194, 199-202

Panzer III, German PzKpfw III, 49Panzer IV, German PzKpfw IV, 20, 25, 49

destroyed at Elsdorf, 20Patton, General George S., Jr., 17, 38Price, L.R. "Slim", 5, 13-14, 16-17, 28, 34,

38Regiments, U.S.

27th Infantry, 184Remagen, Germany, 9-12Rhine River, 9-12, 38Roer River, 9, 10, 17Shaw, William A., 13,34Shrader, Master Sargeant Bryant, 178Sherwood, S.S. Katherine D., 42"Space Engineering", design concept, 50Stillwell, General Joseph W., 43"Super Pershing", T26E4 Temporary pilot #1

in Europe, 28development, 140, 141

Tank Battalions, U.S.1st Marine, 180-1836th, 180, 19314th, Company A, 9, 1719th, Companies A, B, and C, 17, 2663rd, 19464th, 19270th, 18072nd, 180-181, 19073rd, 180, 183-185, 187, 18989th, 180-181193rd, 41,44711th, 448072nd, 180

Tank Destroyer Battalions635th with 90 mm gun T8, 28

Tank EnginesFord GAA, 50

Divisions, U.S.2nd Armored, 343rd Armored, 12-285th Armored, 349th Armored, 9-13, 16-25llth Armored, 381st Cavalry, 180, 18324th Infantry, 182

Diiren, Germany, 17, 20Early, Sgt, 25Eisenhower, General D.D., 13Electric drive transmission, 50, 72Elsdorf, Germany, 17-20Engeman, Lt. Colonel Leonard, 10"Fireball", T26E3 number 38, 17-20Fowler, 1st Lt. Samuel R., 178-179Frankfurt, Germany, 38Gray, Colonel Edward E., 5Gray, Lt. Colonel Elmer E., 5, 13-44, 194Griffin, Captain Gifford, 5, 13-14, 25, 34, 38Grimball, 1st. Lt. John, 10-12, 15, 22, 25Gun Motor Carriages, See Motor CarriagesGun Mounts, U.S.

Combination Mount M34, 68, 72, 228Combination Mount T79, 58, 73, 229Combination Mount M62(T80), 73, 74,

81,229Combination Mount T99, 116, 230Combination Mount T99E1, 116, 230Combination Mount M67(T99E2), 118,

127,230Combination Mount M67A1, 156Combination Mount T102, 118Combination Mount M71(T117), 134,

233Combination Mount T119, 142, 231Combination Mount T126, 150, 153,

232Guns, German Tank

7.5 cm KwK 40, 507.5cm KwK 42, 200, 2018.8 cm KwK 36, 120,200, 2018.8 KwK 43, 28, 120

Guns, Soviet Tank85 mm, 192

Guns, U.S. Tank75 mm M3, 50, 68, 228

with automatic loader, 50, 68, 703 inch M7, 5076 mm Tl, 50, 7276 mm, Ml, 50, 72, 22976 mm M1A1, 50, 58, 72, 86, 22976mmMlA2, 22990 mm M3(T7), 20, 28, 94, 120, 121,

127, 187, 200, 230ejection failure, 17

90mmM3Al, 15690 mm T8, 2890mmT14, 11890mmT15, 14090mmT15El, 28, 14090 mm T15E2, 140, 145, 23190mmT54, 150-151,153, 232105 mm Howitzer M4,134, 139, 233

in T23 medium tank, 139105mmT5El, 119

Hodges, Lt. General Courtney H., 14Hoge, Brigadier General William M., 10

Page 235: Presidio - Pershing a History of the Medium Tank T20 Series. Pershing

Ford GAF, 50, 72Ford GAN, 50, 112

Tank Recovery Vehicle T12, 170-172, 226Tank Transmissions

cross drive, 58, 154electric drive, 50-72torqmatic 52, 112

Tank Transporters M25, modified, 14, 34Tank, German

PzKpfw III, 49PzKpfw IV, 20, 25, 49PzKpfw V, Panther, 25, 194, 199-202PzKpfw VI, Tiger I, 18, 20, 25, 199-202PzKpfw VI, Tiger II, 28, 194, 199

Tanks, SovietT34/85, 175-176, 182, 184-185, 187, 192

Tanks, U.S.T20, 50-58, 204T20E1,50, 68T20E2, 50T20E3, 50-52, 58-61,205T22, 50-51, 62-67, 206T22E1, 50, 51,62, 68-71,207T22E2, 50T23, 50, 51, 72-87, 208-209T23, HVSS, 92-93, 211T23E1, 50T23E2, 50T23E3, 51,89-91,210T23E4, 92T25, 51,81,94-99, 212

T25E1, 51, 104-119, 194-195, 213modified to T26E3 standard, 117-118with 105 mmgunTSEl, 119with integrated fighting compartment,

119T26, 51, 94, 100-103, 214T26E1, 51, 104-119, 194-195, 215T26E2, see M45T26E3, see M26T26E4, 28, 51, 134, 140-145, 218T26E5, 51, 134, 146-149, 219T40, 156M4 Sherman, 41,49, 50M24, Chaffee, in Korea, 175-177M26 (T26E3), Pershing, 9-46, 51, 104,

117-118, 120-133,217in Korea at Chinju, 178-179in Korea at "Bowling Alley", 184,185versus Panther and Tiger, 18, 20, 25

194, 199-202versus T34, 182, 184-185, 187, 192improvement in ballistic protection,

121flotation gear, 130with Rocket LauncherT99, 132with twin machine gun mount T121,

133with fender mount machine gun, 133

M26A1, 150, 156-157, 193in Korea, 193

M26E1, 150, 153

M26E2, 58, 150, 154-156M45 (T26E2), 51, 134-139, 193, 216

in Korea, 193M46, 58, 156, 192

Tauss, Captain William, 42 , 45Tiger, German PzKpfw VI, 18, 20, 25, 28,

194, 199-202Timmerman, 2nd Lt. Karl H., 9-12Torqmatic Transmission, 52, 112Tracks

T48, 62, 72, 82, 204, 206, 207, 208, 209T51, 52, 204, 206, 207, 208, 209T66, 94, 95, 97, 212T80, 92, 97, 211,212T80E1, 22, 120, 122, 129, 136, 146,

147, 159, 165, 167, 169, 170, 214,216, 217, 218, 219, 220, 221, 222,223, 224, 225, 226with extended end connectors, 146,

147, 165, 167, 169, 170, 219,223, 224, 226

T81, 100, 101, 108, 114, 120-121, 151,183, 214, 215, 216, 217, 218, 220,221,222,225modified, 122

T91, 122On T20E3 medium tank, 58, 205On T23E3 medium tank, 87, 89, 210On T25E1 medium tank, 114, 118, 213

Zebra Mission, 13-40

240