I

F R L -RE-1-i

OR THELOW-TEMPERATURE LUBRICANTS" •.• FOR THE M134 AIRCRAFT MACH4INE GUN (MINIGUN)

TECHNICAL REPORT -

~DEC N-.. , ; I ,...

• .: •. ,Fred Novekoff I 19:,;!7.1

February 1971CENC &

SCIENCE & TECHNOLOGY LABORATORY

RESEARCH &$ ENGINEERING DIRECTORATE

U. S.iARMY WEAPONS COMMAND

This document has been approved for public release and sale; itsdistribution is unlimited. Roprodu.. d b.

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DISCLAIMER:

The findings of this report are not to be construedas an off~ciai Department of the Army.. position unless sodesignated by. other authorizeddouuments*. .*,

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I ORIGINA T rNG c IAvj Y (C•opof. St RthO) ,RPORT SEIICURITV CLAESIFlCATION

S. Army Weapons Commend |__ IResearch and Engineering DirectorateRuck isiand, 1111nols 61201

3 REPORT TI1LE

LOW-TEMPERATURE LUBRICAV-S FOR THE M134 AIRCRAFT MACHINE GU.N(MINIGUN) (U)

4. DESCRIPTIVE NOTES (Type Of PepOI and inVau.Iv daSes)

Final Report I June 1970 - 30 November 19O70.A TIORISI (PI..t Wame, middle fIlti.I, lIs. Peine)

Fred Novekoff

6 REPORT DATE 7a. TOTAL NO, OF PACES 71). NO. OF REPSFebruary 971 19 1 4

00. CONTRACT OR GRANT NO. go. ORIGINATOR'! 64EPORT NUIt.OERIEI

. PROJECT "O. RE-71-1DA 1G062105A107

€. 9b. O TMrR REPORT NOW5 (Anji , ý ha nu*Ib~r@ thtia r ha -1be gried

AMS Code 502E.11.891d.

10 DISTRIBUTION STATEh.'4NT

This document has been approved for public release -and sale; itsdistribution is unlimited.

I'. SUPI.EMENTARY NOTES 2. SPONBORING MI1.iT:.RY AC TIVITY

.U. S. Army Wealpon3 Command

13. AOISTRACTlbrcn\

An investigation of low-temperature lubricantS for the M134 AircraftMdchine Gun (Minigun) was requested by Aircraft Weapons SystemLaboratory (AMSWE-REW-G). The tests were con ýcted at Air ProvingGround Center, Eglin Air iorce Base, Florida. .Two lubricants, specifi-cations MIL-L-14107(LAW) and MIL-L-4615U(LSA-T), and two experimentallubricants, AWC #1 and AWC'#6 were investigated. The wEaron used forthis Investigation was the Minigun, 7.62MM, Auton;6itic Gun GAU-2B/A.The purpose of the test was to determine which lubricant was suitableunder sustained firing conditions at ambient temperature, at (pF,-301F, and -65*F. Data were obtained concerning malfunctions, ratecf fire, time to reach peak rate in seconds, oil application, roundsfired, barrel temperature, and receiver temperature. It was foundthat LAW, the currently authorized low-temperature (0U to -65*F)lubricant for many weapons, could not be recommended it any tempera-ture or the minigun. LSA-T performed better than either AWO #1 orAWC #6 at ambient temperature. At OOF no significant difIereýnceoccurred between these three compounds. However, at -300F, AWC #1was superior to the other three. At -65'F, AWC #1 and AWC #6 gavebetter Performance than LSA-T. (U) (Novekoff, Fred)

D D '° 1473 EPLACES 00 FORM 147.... JAN , 4. ,IC . Unclassified

0-curity C•Isnlfication

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ROLE~ WT ROLE WT R OLE

1. Lubricants

2. Lubricants, Low Temperature

3. Lubricants, Aircraft Weapons

4. 7.52MM Automatic Gun GAU-2B/A(Minigun)

Unclassitiedsecurity Classification

L

AU

SCIENCE AND TECHNOLOGY LABORATORY

RESEARCH AND ENGINEERING DIRECTORATE

U. S. ARMY WEAPONS COMMAND

TECHNICAL REFORT

RE-71-1

LOW-TEMPERATURE LUBRICANTSFOR THE M134 AIRCRAFT MACHINE GUN (MINIGUN)

Fred Novekoff

February 1971

DA IG062105AI07 AMS Code 502Eo11 801

This document has been approved for public release and sale;its distribution is unlimited.,

ri

ABSTRACT IAn investigation of low-temperature lubricants for

the M134 Aircraft Machine Gun (Mini un) was requested byAircraft Weapons System Laboratory (AMSWE-REW-G). lhetests were conducted at Air Proving Ground Center, EglinAir Force Base, Florida. Two lubricants, SpecificationsMIL-L-14107(LAW) and MIL-L-46150(LSA-T), and two experi-mental lubricants, AWC #1 and AWC #6 were investigated.The weapon used for this investigation was the Minigun,7.62MM, Automatic Gun GAU-2B/A.

The purpose of the test was to determine which lubri-cant was suitable under sustained firing conditions atambient temperature, at OF, -30 0 F, and -65'F. Data wereobtained concerning malfunctions, rate of fire, time toreach peak rate in seconds, oil application, rounds fired,barrel temperature, and receiver temperature. It was foundthat LAW, the currently authorized low-temperature (00 to-65°F) lubricant for many weapons, could not be recommendedat any temperature on the minigun. LSA-T performed betterthan either AWC #1 or AWC #6 at ambient temperature. AtOF no significant difference occurred between these threecompounds. However, at -30'F, AWC #1 was superior to theother three. At -65'F, AWC #1 and AWC #6 gave better per-formance than LSA-T.

ii

FOREWORD

This work was performed in part under Project Directive0019VO01 and AMS Code 5dE.1i.801. under prnjet titl!

"Lu ,rica-,•L, Friction and Wear." The subtask title was"Weapons Lubricant Field Tests." Additional work was per-formed under AMS Code 5142.12.l1209.15, project title"Development of Aircraft Gun Type Subsystem," with workunit title "Investigate Low-Temperature Lubricants for Usewith the M134 Machine Gun,"

iii

CONTENTS

Page

Title Page 1

Abstract ii

Foreword iii

Table of Contents iv

Objective

Introduction

Procedure

Results and Discussion 4

Conclusions and Recommendations 12

Literature Cited 13

Distribution 14

DD Form 1473 (Document Control Data - R&D) 18

v

iv

OBJECTIVE

The objective of this investigation was to determinewhich low-temperature (00 to -65OF) lubricant should bespecified for use on the M134 Aircraft Machine Gun (Minigun).

INTRODUCTION

The Science and Technology Laboratory was requestedby the Aircraft Weapons Systems Laboratory (1) to investi-gate the possibility of using MIL-L-14107 for the M134 gunundeo" sustained firing at temperatures below -30°F dnd(2) to develop a polytetrafluoroethylene (PTFE) lubricantfor low temperature use.

Data were unavailable at all temperatures, and the datathat were available led to conflicting recommendations onlubrication. Tests at Aberdeen Proving Ground' indicatedthat LSA-T was inadequate at -65°F. Lubrication Order9-1005-257-122 recommends the use of LSA-T from above +32'Fto -]0"F. This recommendatLion conflicts with that of theScience and Technology Laboratory which recommended the useof LSA-T down to -390F.

Firing tests were conducted in June 1969 at Eglin AirForce Base to evaluate and qualify nine LSA-T formulationsreceived from various suppliers. 3 These formulations weretested on the Minigun at high temperature (180 0 F), atambient temperature (40' to 1000 F), and at low temperature(-30 to -65°F). Results of this test indicated that LSA-Tis adequate to only -30'F. However, an experimental lubri-cant, AWC #6, performed adequately at -65F, None of theseformulations were tested under sustained firing conditions.Therefore, additional firing tests were needed.

PROCEDURE

A. Materials Used

The lubricants used in this investigation arebriefly described below:

Lubricant MIL-L-14107B(LAW) is a fluid and is theauthorized arctic preservative lubricant for sinall-armsweapons under cold-weather conditions (0' to -65'•F), The

lubricating oil consists of a tetra-alkyl silicate intowhich additive materials have been incorporated to inhibit

Aint ad ox4 dati-n

Lubricant MIL-L-46150(LSA-r) is a semifluid com-pound with 2" per cent polytetrafluoroethylene (PTFE).This is a thickened synthetic diester lubricant with in-hibitors that provide resistance to corrosion and oxidation.

Lubricant AWC #1 is a semifluid compound containing10 per cent PTFE molding powder. This lubricant is a sili-cate ester thickened with lithium stearate and contains anantiwear additive, oxidation inhibitor, and a corrosion-in-hibitor system, in addition to the PTFE powder.

Lubricant AWC #6 is a semifluid compound with 5per cent PTFE added. This lubricant is a pelargonic acidester thickened with lithium stearate, and contains anantiwear additive, oxidation inhibitor, and a corrosion-inhibitor system,

B W eapon Used

Two Automatic Guns, 7.62MM, GAU-2B/A, mounted onAircraft Machine Gun Module 7.62MM, Air Force Model MXU-470/Awere used. The gun module drum for this weapon is capableof hulding 2000 rounds. The 7.62MM Automatic Gun is anelectrically driven, six-barrel, Gatling-type weapon withlow (2000), medium (4000), and high (6000 rounds per minute)firing rates. It is air-cooled, can be belt- or drum-fed,and is fully automatic, The six barrels have a fixed head-space and are of the quick-change type. This weapon, commonlycalled the Minigun, is presently used in a helicopter arma-ment function, The major components of this weapon are rotorassembly, six bolt assemblies, six removable track, gunhousing, safing sector, housing cover, guide bar, rear gunsupport, six barrels, and barrel clamp.

The ammunition is a 7,62MM cartridge-linked, 4-ball;and l-tracer M13 linked, covered by FSN 1305-926-3942-A165.The ammunition was obtained from Hill Air Force Base, Ogden,Utah, but shipped from Lexington Blue Grass Army Depot,Richmond, Kentucky.

C. Firing Tests

All firing tests were conducted with the weaponsset for automatic fire at the high rate of 6,000 rounds perminute, Details of each test are outlined in the followingparagraphs:

1 Firinq Test at Amhipnt TPmni t'c',,*'o

(400 to 100 0F)

Th, wc " po, s w. , rer 1 disa se,,,unIe d d cleaned of all1traces of lubricants and residues with Stoddard Solvent(PD.680 "Dry Cleaning Solvent"), The parts were then driedwith the use of an air hose and moisture-free compressedair. The lubricant was then applied generously to the gunwith a brush. The front and rear bearings of the weaponare lubricated with a special lubricant; these bearingswere excluded from the test, After lubrication, the weaponwas moutited on the stand and test fired. The two weaponswere used alternately in these tests; while one was beingfired, ithe other was teing prepared for the next test. Six-teen '1,000 round-bursts were fired with each lubricant, ex-cept that the LAW was not used in this test. In each test,the weapon being fired was cooled for two minutes followingeach odd numbered burst and cooled to ambient. tempcraturefo)lowing each even-numbered burst, The rate of fire andthe peak rate (reached within 0.5 second) were recorded.Barrel temperatures were determined for the ambient testsonly. When the sixteen bursts were completed, the gun wasexamined for dry area., wear, galling, carbon or, other de-leterious effects.

2o Firinq Test at O°F

The weapons were pripared in the same way as thosefor the ambient test, except for the following changes.

1 (a) Each gun along with the ammunition was soaked at O°Ffor four hours before firing. (b) The barrels were cooledto l00!1O0 F after each 2,000 rounds. Again, !6,000 roundswere fired for each lubricant except for LAW.

3. Firiig Test at *-30°F

The procedure was the same as above, except thatthe lubricated gun and the ammunitiorn were so,.\ked at -30*Ffor four hours before firing. Here, 16,000 roands were"fired for each lubricant, including the LAW.

4• Firing Test at -655F

The procedure, outlined abcve, was again followed,except that the lubricated gun and the ammunition weresoaked at .65°F for four hours, The weapon was expected toreach peak rate within l .0 second at this temperature.Again, 16,,000 rounds were fired for each lubricant,

3

RESULTS AND DISCUSSION

Results of the firing tests are shown in Tables Ithrough V,, LSA-T performed better than AWC #1 or AWC #6at ambient temperature on the basis that the weapon accel-erated to the highest rate in the shortest time (Table I).No significant difference is apparent in the performancebetween these three compounds at 09F.

The data at -30'F (Table III) show that the AWC #1 wassuperior to .he other three lubricants tested; based on thcihighest rate, MIL-L-14107 is considered unsatisfactorysince jamming occurred.

At -65%F, the AWC #6 gave slightly improved performanceover the AWC #1 and the LSA-T (Table IV), Again, boltsjammed when MIL-L-14107 was used,

in Table V, average firing rates and barrel tempera-tures are itemized under the test conditions described.The barrel temperatures were taken at every 1000-round burstso that the maximum temperature reflected the end of thesecond l000-round burst before cooling to ambient tempera-ture. This temperature varied dependent on the type of day.The firing rate was also taken at every burst and reflectsthe average peak firing rates., Since the feed ammunitionmodule held 2000 rounds, the load affected the firing rate.Current requirements for the rate of fire are based on a100-round belt load which requires 6000 rounds per minute.This acc~unts for the lower firing rates recorded.

The Minigun, lubricated with MIL-L-14107, malfunctioned3 times in 277 rounds (Table Ill footnote). To provewhether the malfunctions were caused by the lubricant, LSA-Twas applied liberally to the rotor and bolts. The remain-der of a 2000-round complement, or 1723 rounds, was firedin two bursts without a malfunction. MIL-L-1410? lubricantwas then tried at -65FoF The bolts jammed at 57, 100, and400 rounds (Table IV footnote). The gun was theni removedand no further testing was conducted on MIL-L-14107. Recentlubricant friction and durability tests 4 under simulatedweapon conditions at ambient temperature also show that LAW'as little or no lubricating ability compared with LSA-T.

4

ITABULL iI

ACCELERATION AND FIRING RATES AT AMBIENT TEMPERATURE

Firing Rate, rounds/minute

Time, second LSA.-T * AWC #1 ** AWC #6 *

0.1 3514 3621 3736

0.2 5014 4621 4814

0.3 5657 5207 5242

0.4 6171 5478 5385

0.5 6271 5521 b40J

0.6 6271 5521 5492

0.7 6271 5521 5529

0.8 6271 5521 5579

0,,9 6271 5521 5621

1.0 6271 5521 5621

*•-Barrel temperature after 1,000-round burst: 920*F

*•*-Barrel temperature after 1,000-round burst: 980'F

k**-Barrel temperature after 1,000-round burst: 1080°F

5

TABLE II

ACCELERATION ANI FIFING RATES AT 0°F

FiringRate, rounds/minute

Time, second LSA-T AWC #1 AViC #6

0.1 4221 4038 4108

0.2 5614 5638 6092

0.3 6179 6323 6446

0.4 6386 6469 6500

0.5 6436 6554 6546

0.6 6493 6554 6546

0.7 6514 6554 6546

0.3 6529 6554 6546

U. ') 6543 6554 6546

1,0 6543 6554 6546

6

I

TABLE III

ACCELLRATIOfl ANO FIRING RATES AT -30°F

Firing Ratet rounds/minute

Time, second *MIL-L-14107 LSA-T AWC #1 AWC #6

0.1 3000 3950 4200 3900

0.2 3900 4700 6300 5100

0.3 5400 5750 6450 5700

0.4 5800 6200 6600 6090

0.5 5900 6200 6700 6090

0.6 -- 6200 6700 6090

0.7 -- 6200 6700 6090

0.8 -- 6200 6700 6090

0.9 -- 6200 6700 6090

1.0 -- 6200 6700 6090

*Malfunctions - bolts jammed after 120, 112, and 45 roundsin three trials

1

T An 1 T V

.*.v.~ ATC AT -9 O

ACCELt-HAKiNU AND FIRUING "RTi E

Firing Rate, rounds/minute

Time, secnnd *MIL-L-14107 LSA-T AWC #1 AWC #6

0.1 3000 3757 4050 3450

0.2 5200 4886 5400 5100

0.3 5700 5443 5850 5850

0.4 5800 5471 5900 5850

0.5 -- 5529 5900 6000

0.6 _. 5629 5900 6000

0.7 5743 5900 6000

0.8 -- 5743 5900 6000

0.9 .. 5743 5900 6000

1.0 -. 5743 5900 6150

*Malfunctions - bolts jammed after 57, 100, and 400 rounds

in three trials

8

TABLE V

AVERAGE FIRING RATES AND BARREL TEMPERATURES

Firing Rate/--rounds/minute

BarrelLubricant Temp., OF Ambient O°F -30°F -650 F

AWC #1 880 - 1080 5500 6520 6590 5625

AWC #6 810 - 960 5690 6700 5880 5850

LSA-T 900 - 910 5914 6460 6125 5640

MIL-L-14107 --- No No *

Test Test

*Malfunctions occurred. Bolts jammed because ofdeficient lubrication.

9

CONCLUSIONS AND RECOMMENDATIONS IBased upon the tests conducted, MIL-L-14137B lubricant

cannot be recommended fur use at any temperature on the7,62MM Automatic Gun GAU-2B/A, known as the Minigun.MIL-L-46150(LSA-T) can be used from ambient temperature to-30*F. Lubricant AWC #1 or AWC #6 can be used satisfactorilyfrom 00 to -65°F on this weapon.

It is recommended that a purchase description be preparedestablishing requirements and test procedures for ExperimentalLubricants AWC #1 or AWC #6, This document will make thematerials readily available within the military supply system.

10

LITERATURE CITED

1. Steier, G. M., "Final Report on Comparison Test ofPod, Aircraft Gun 7.62MM, XMIBEl (QualityAssurance)," Aberdeen Proving Ground ReportAPG-MT-3431, January 1970.

2. "Armament Pod, Aircraft, 7.62 Millimeter Machine Gun:XM18 and XMI8EI," Lubrication Order L09-257-12,10 October 1969.

3. Novekoff, F., "RIAPD-688 Lubricant, Semifluid LowFriction (Automatic Weapons) for Automatic 7.62MM,GAU-2B/A," U. S. Army Weapons Command Science andTechnology Laboratory Technical Report , inprepa rati on.

4. Bornong, B. J., "Lubricant Friction and DurabilityTests Under Simulated Weapon Conditions," U. S.Army Weapons Command Science and TechnologyLaboratory Technical Report RE-70-190, November1970.

11

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