Lubrication Clockwork Fuze Mechanism for Bomb UK 1948

7/28/2019 Lubrication Clockwork Fuze Mechanism for Bomb UK 1948

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TECH.OTE ARM.407 i' TECH.OTE ARM.407 DeclPADS

FARNBOROUGHANTSTECHNICALOTE o:RM .407 REVIEWEDN :

Illt+IrSDat _2ai*;Signatort LUBRICATIONF

CLOCKWORKUZEMECHANISMSFOROMBS


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TechnicalNoteNo.Arm.407December,1948

ROYALAIRCRAFTESTABLISHMENT,FARNB0R0UGHLubricationof Clockwork FuzeMechanismsforBombs

byF.Hov/ick

R.A.E.ef: Arm.S.1426/RRG/FH/31S U M M A R Y

Testsofthe valueofmineraland non-mineraloils,siliconefluidsandgreases,and colloidalgraphiteaslubricantsforclockworkfuzemovementsaredescribed.hework hasparticularreferencetotheefficacyof the variouslubricantsunderextremesoftemperature.ometestswithno lubricantare recorded.Itisconcludedthatsilicone fluidsandgreasesareat presentthe mostsuitable foraircraftbombfuzerequirements.

LISTOFCONTENTS Page1ntroduction2ethodofTest3esults3.1 on-MineralOils


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4ATechnicalNoteNo.Arm.407

LISTOFAPPENDICES AppendixTestnFuzevi.IIIA.IIubricatedwithFluidSiliconesFuzeM.IIIA.II. LubricationwithSiliconeGreaseIExtractsromecordsfestsnColloidalGraphiteIIListfLubricatingOils, etc. V


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TechnicalNoteo. .Arm.407

1ntroductionFailureswhichccurredwithlareuzes, e.g. theM.III (American)duringhewaryears, werehownobeuenpart toheubricant.Thiseterioratedduringtorage, especiallyatighemperaturesndfailed hencalleduponounctionat extremeowemperatures. TheobjectfhisNotesocollectndecordheesultsfhexperi-mentalworkcarriedutnubricationfuzemechanismsordverseconditions.

2ethodfTestThevalueof alubricantassuchwasassessedbycomparisonwith

thebestofthenon-mineraltypesof oilsuchasEzraKelleyoi lusedbywatchmakersforover a century.estswerecarriedoutwithtwotypesofmovement.hefirst wasanordinary2" drumlevermovementasusedin British flare fuzes,thebalancegiving4beatspersecond,capableof runningfor30hrs.withonewinding.ointstobelubricatedincludedlowandhighpressures withinversehigh andlowspeeds.hebalanceincludedastaticconditionbetweeneach beatwith rapidacceleration anddeceleration.ncontrast,thesecond,theAmerican M.IIIfuze movement,had a rangeof6-92secondsand an escapementspeedof196 beatspersecond.nessentialrequirementofthismovementwasitscapacitytoselfstart. (AlltheAmericanflare fuzeshadthesame basicclockworkmechanism).

Runningtests wereconfinedtoth e2 "drumtypeasabove andpreparationofthetestmovementinvolvedreducing frictiontoa minimumandensuringuniformity of balancewheelperformance.he balance wheelarcwouldnaturallydiminish attheendofa 2 4h r .runandwould befurther diminishedbydeteriorationofthe lubricant,untilfailuretocompletea2 1 + hr.period occurred.ovementswere placedinsealedcanisters for bothhighandlowtemperaturetests. Earlytestsathightemperaturecompriseda2 1 + hr.periodat +60G.histimewas,laterincreased to48hrs. ^^>

WiththeM.IIIfuzemovementdeteriorationofthe lubricantwouldsooncausefailureduetoth eheavyloadingatthepressurepoints,especiallytheescapement,where pressureforimpulsingth e balanceisbypointcontact.orassessingthevalueof anewlubricant,movements,usually 12 innumber,were chosenwithknownrecords,andatiming datumprovidedbyrunsatnormaltemperature.leansingwaseffected withpetroleum etherwithseparate rinsing,andifnotprovided,countersinksmadefortheterminalsofthe bearingpivots.arewastakentoavoidover-lubrication whichwoulddefeattheobjectoftheprovision ofthesecountersinks.

Thetestsmadewithcolloidalgraphiterequiredpreliminarypreparationofth ebearingsurfacesbysmoothing,furthersmoothingofthegraphiteafteritsapplicationbeingdonewithpeg wood.ainspringswerebesttreatedwithAlcoholResin dispersion.


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TechnicalNoteNo.Arm.407

the lowesttemperatureatwhichfunctioningcouldbereliedupon.3 . 2 MineralOils

Asa resultofthefailureofnon-mineraloilstheAmericansinearly1944changedto amineraloilWS.429*hisloweredthetemperaturelimittoabout-50C " b u tintroduceddifficultiesduetocreepingandgummingonstorage.heseeffectsbecomeextremelypronouncedundertropicalconditions.reepingwascounteredbytheuseofaliberalapplicationofthelubricant.orkdirectedtofindingamineraloillubricantforBritishfuzemechanismsledtosimilarresults,the oilDTD.44/Dbeingfinallychosen.hetendencytooreepwasovercomebytheuse ofa 'non-spread dope'.vaporation andgummingunderprolongedhightemperaturestoragestill remainedaproblem butth erapidityoffuzeexpenditureunder wartimeconditionspermittedittobetemporarilyshelved.3 *3 SiliconeFluidandGrease

A comparativerunningtestoverconsiderable periods,showedthatasalubricantsiliconefluids did notcomparefavourablywithconven-tionallubricatingoils.heirstabilityandsmall viscositychangeathighandlowtemperaturewerehoweverremarkable,and theygavereliablelowtemperature operationto-50to-55C.ilicone greaseDC.33hadequallyvaluableproperties.heinferiorlubricatingqualitieswerenotconsideredto bedetrimentalfor the'onceonly'runrequiredoffuze mechanismsatthetimeof theirexpenditure.

ParticularsofthesetestsaregiveninAppendicesIandI I .3 4 ColloidalGraphite

Clockparts preparedasshownon Pig1weresubjected toacon-tinuousrunningtest.atisfactoryresultsdownto below-70Cwereobtained,butthe performanceofcolloidalgraphiteasalubricantatnormaltemperaturesisinferiortothatofanyof thefluid lubricantstested.etailed resultsofthe testsappearin Appendix III.3 3 Lubrication Absent

TestswithdegreasedandunlubricatedM.IIIfuzesestablishedtheirunreliable performanceinthiscondition.esultsof thistestappearin Appendix I(Table I).4 Conclusions

Theeffectivelowtemperature rangeofthenon-mineraltypesoflubricantsslimitedtoapproximately -20C. Theyhave good lubrica-tingandstaying qualities.

ThemineraltypesNos.8,9, 10and 1 1(seeAppendix IV )represent


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Technicaloteo.rm.407Colloidalraphiteannlybeppliedwhereheearingurfaceisufficientlyenerous* Pointontactsoralance/heelbearings

ofhe"rumlockworkmovement, orcapewheeloalletfhed.Illbeingquivalentooubricant, astwouldcrapeffnction. Intheestshebalanceivotswereiledorheontinuousunningestatormalemperature, andheormaloatinggaveestesults.Note: TheermanNo.17,ongdelaylockworku2eadnppreciable

thicknessfraphitenhecapewheeleeth,utnorderoessenfriction, hardenedndpolishedteelnsertswerencludedorivotbearings. Withheseofinementsts4r. runppearedobesatisfactory.

SiliconeFluidsndGreasesoverwideangefiscositiesndadvantageanbeakenfhisact to suit articularequirement.Theangerom00/50C.S. to00/200/CS.asoundobemostuitable.Where igherviscositywasoquired, asormainsprings, etc.iliconeGreaseD-33satisfactory.Anyendencyoreepwithheowerviscositiesanbeounteredbyhesefon-spreadope, andoncompatibilityaseenbserved.

Attached;-Pig.1

rg.rm.55524-Appendices V.

AdvanceDistribution:-DArmRD ADArmR ADAmiRDRDArm5RDArmR2RDInstASec. O BCEADGSAR TPA5AIB0 DRAE DDRAE(W)IAPDept. (Mr. Honick)Chein .Dept. (Mr.tkinson)Arm.Dept. 0


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COMiilDENTlAt-Technicaloteo.Am.407

APPENDIX.ITestson Fuse M.III A.IIlubricatedwithFluid Silicones

(Test RecordNo.1019dated14 Jan.1947)Introduction

The M.IIIfuze wasoriginallylubricated withporpoise jawoil(Grade watchoi lU.S.Spec. 2-47) >" b u tin January,1944*thelubrica-tion wa schangedtoamineraloil(V.S.429manufactured byth eStandardOilGo.andconformingtoU.S.Spec.AN0.4).

FuzeslubricatedwithGrade watch oi l werefoundtofunctionsatisfactorilydowntoatemperatureof-35C(TestRecord No.F85jAlthoughtheuseofmineraloilgaveaslightly lowertemperatureforreliableoperation,itwa sfoundthatthelubricantcrept andevaporatedduringtropicalstorage,causingth efuzetofail.

Effortshavethereforebeenmadetofindalubricatingfluidtoenablethe fuzetowithstandprolongedtropicalstorageandsubsequentlytofunctionsatisfactorilyatalowtemperature.hefluidsinvestigatedin thesetestsareaseriesoffluidSiliconesmanufactured by Messrs.DowCorning. These fluids,obtainableinarangeofviscosities,areveryinvolatileandtheirviscositydoesnotchangegreatlyoverawiderangeoftemperature.ObjectofTests1o determineif lubricantisnecessaryforth e fuze.2oinvestigatetheperformanceofthefuzeatlowtemperaturewhenlubricatedwithfluidsiliconesandtocomparetheresults witha fuzelubricatedwithmineraloil.3oinvestigatetheperformanceofthefuzeatlowtemperatureafter prolongedstorageat70C whenlubricatedwithfluidsilicones.MethodsofTest1ix fuzesweredegreasedandtestedatnormaltemperaturewithasettingof92seconds. Theresultsaregivenin TableI .2ighteenfuzesremaining fromthebatchoffortyeighttestedinJune,1945,(TestRecordF15&)were dismantled and degreasedwithpetroleumether.ttentionwasgiventothepivotsand bearingstoensuresmoothness.ountersinkswereprovidedforthelubricantandnonspreaddope was applied j otheadjacentparts.

Sixteenof thefuzesingroupsoffourwere lubricatedwith DowCorningsilioonefluidsoffourviscosities,viz.350,200,100and 50Centistokes. Themainsprings weretreatedwithcolloidalgraphiteina resin-alcohol dispersion*he remainingtwofuzeswerelubricated


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SECRETTechnicalNoteNo.. A n n . 4 0 7

fuzeswereimmediatelytimedat laboratorytemperaturewith anaccuratestopwatch.heresultsofth etestsat-60C,-53Cand -50CaregiveninTableIITestsNos.4,5and 6 .3hefuzeswereplacedinanovenmaintainedatatemperatureof72 to74Cduring workinghours.uringotherhourstheoven wasswitchedoff. Thesi x weeksperiodofstoragewas madeupasfollows:-

2 periodsof 48hoursathightemperature2 i i4 " " "

26" 8 ""gIIZ)tII Total70

Afterremovalfromtheoven,the fuzeswereplacedinarefrigeratorandtestedatatemperatureof-60C.heresults aregiveninTableIITestNo.7.4welveofthefuzesweredismantled,th elubrication ofthe main-springs changedfromcolloidalgraphitetoDowCorningSiliconeCreaseD33*th emechanismlubricatedagainwith thesiliconefluidsandatestmade at-60C.heresultsaregiveninTableIITestNo.8.Conclusions

Ofthesixfuzestested withoutlubrication,threestoppedaftera fewsecondsonthefirsttest,whilsttheremainderfailed afterseveraltests.ubricationisthereforeessentialtot h e . f u z e . . .The useof fluidsiliconesinsteadof oilgreatlyimprovestheperformanceofthefuzeascomparisonof TableIIwith TablesIandIIofTestRecordNo.F156willshow.fter a prolongedtropicaltest,thefuzeisstillcapableoffunctioningcorrectly at-60C,thelowesttemperatureatwhich the testsweremade,when lubricated withDowCorningfluidsiliconesType500of viscosities200,100or 50Centistokes.Thelubricating propertyoffluidsilicones beinglessthanoils,

itisconsideredadvisablethatallslidingsurfacessuch aspivots,etc.bemadeassmoothaspossible.urthertestsare beingmade " w i t hfuzeslubricated 'withsilicone grease whichhasth e advantagethattheapplication ofnonspreaddopetothemechanismsisnotnecessary.TABLEI

TimingTestsonFuze I I . I l lA.IIwithoutlubricantAllfuzestestedatmax.settingof92sees,andat normaltemperatureFuze N o .

12

Timeinsees,from releaseofclockworktofiringStartedandstoppedafterabout15sees.


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CONFIDENT!.TechnicalNote o. arm.407i f fPMDIXU

Fuze.i.Ill, ,.fIILubricationwithSiliconerease(TestRecord o. 1026ated6my, 1947/Introduction

Theequirementfombroup, Ann*Dept..A.E. for upplyof30uzesoiveeliableperationat500, hasyieldedesultswhichareonsideredobefufficientnterest tobepresentednheormof Testecord.TheperformancefSiliconeFluidssubricantssiven in

TostRecordNo.1019 (14thanuary, 1947; issuedpreviously. SubsequenttestswithSiliconerease 3 3 haveivenoodowemperatureesultsandtssemakeshepplicationfon-spreaddopennecessary. Thetw oourcesfmanufacturefFuzeM.IIIreG.T.I. andW.CCo. andpreviousests havebeen'madewith"G'.T.I.seingmoreeliable, butthosevailabletresentref / ' .O.Co'smanufacturendweresedortheest. To improveelftartingt asecessaryoandinishhoworkingurfaces, andoessenheikelihoodfailureofhestartingdetentoject.bytsbeing pheldnpositionbyhe slot intheimingdisc, its.hookprovidedoerkthelockworkntoction;waseducedneightbypproximatelynealf.Object ofest

Toprovide0uzesM.III..II-"92-sec. delayorombTailmokeGenerator, tounctionat50C.L ie thod

Toprovide means ofxamininghelockworkscapement inction,it asecessaryoprovideightingolessn"fuzesofG.T.I,manu-facture, andossist inelftarting, theworkingurfaceswerefinishedmooth.Theubricantwasppliedveryparinglyduringssembly.Timingwastongestdelayf2econdswithrrorsnhesidesheendencysoaintowemperature.Theefrigeratorbeingsedtight gaveateast 12rs..athetestemperaturebeforeimingheuzes, theemperaturessedbeing-63C, -57Cnd53C Doubtfuluzes, after.adjustment,wereivenainal testt59C Fu'zesNos.:9nd9wereejected, theormerbeingeplacedbyxincludedormergency) and o.19by uze'rompreviousest onSiliconeFluid500/100smarked (5). Thisassedandesteds shownwithoutalteration.

ResultsForhepurposeequiredheesultsreuiteatisfactory. A


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TechnicalNote o. Arm.407

APPENDIXIIIExtractsromecordsfestsnColloidalraphite

"Allbearingurfacesndgeareethwarereatedwith 'dag'colloidalraphitedispersednndustrialpiritoprovideitherdrygraphiteilmrndsorbedilm,whilsthepringtripsweretreatedwith Resin/Alcoholispersionwhichurxperimentshowsmoreuitableorhisypefreatmenthanheotherproduct"."Thepartsweressembled, thebalancewheelivotswereubricatedwithKelleylockoilndn9thune, 1946hemovementswereetrunning. Thebalancewheelivotbearingswereotubricatedwithgraphite, asheesignwasnsuitableorhisubricant. Itasobservedhathebalancewheelrcwaspproximately80. At thendof 24ourshemovementswareewound. Theewinding asarriedutdaily, excepttweek-endsndnytoppageduringhe4ourestperiodoted.Theirstmovementoail asNo.15which, afterunning08ours,wouldotomplete 4ourun. Winding asontinuedndompletefailureounccurredafterpproximatelyhreemonths.Theemainderfhemechanismsontinuedounorrectlyor4

hours, somewithdiminishingbalancewheelrcndccasionalailures,untilfterboutourmonthsnOctober5th, 1946,Nos.1, 2, 12 , 13nd14,wouldotunor4ours. By ecember2th946,afterbout sixmonthsest,os4, 6, 8nd1 alsowouldotlwaysunor4ours.O nanuary0th947, afterboutevenmonthsest, thepositionwashatNo.15wouldnotun, Nos.1, 2 , 4, 6, 8, 11 , 12 , 13nd4wouldnotomplete4oursunning,whilst theemainingive, i.e. Nos3 j 5,7, 9nd0wouldgenerallyunor4oursbutheirbalancewheelrcwasnlybout80.Theesultshowhat lightlybetterperformanceasbeenivenbyheormaloating (Nos .1 to nd o0) asomparedwithhedsor-bedilmNos .11 to5) ThedifferencenperformancebetweenNos.1 toand o0snsufficientoustifyhepplicationfheoatingothegearwheeleethndheinions.Theesultsmaybeomparedwithmovementsubricatedwithuitableoilromwhicheliableerviceorateast twelvemonthsasbeenb-tained. Themovementsnhis testgaveeliable serviceorbout0o50^nlyfhisime.Foruchpurposesoweversfuzomechanisms,whereheotalrunningimencludingestingshort, theperformancemightberegardedsatisfactory.Theoatingfhemainspringswithdag'dispersedn esin-


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CONFIDENT!*Technicaloteo. Arm.407APPENDIXV

ListfLubricatingOils, etc.Non-Mineral1.zraKelleyWatchrClockOil, Newedford,Ma3s.2..P.ye iii n IIi

Aliens,.304. Stafford Allen,ondon.4. Aliens.427.

NotesPorpoiseawPorpoiseawsubstituteBlackfishead

oil

Mineral5..T.D.44A6..S.429/A.N.04tandardOilo.U.S.ii.)0utf

) services7 ..TD#561British equivalent of No.6.Ibeing

)corrosive8.S EdgarVaughanGcmrnercial Typesseday contractors9..1211 AlexanderDuckham Commercialypesusedbyontractors.10./Iobius Hannover Gommericalypessedbyontractors.11.ntava91. =D.T.D.8119 Commercialypes usedbyontractors.

LowTemperature1 11

Silicone1 2 . SiliconeFluid Type2005OC . S . DowCorning1 3 .1 4 .1 5 .1 6 .

" 000 0" "00001 1 1000

Grease D. C 3 3 *

it1 1 11 1 1 i

Highndow Temperature


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[dstl]Information('nitreKnowledgeServices[dstl]Vuium Down,SalisburyWiltsSP 4aiQId 0I9S0-6I37S3 F a >0IM0-6139W

Defense Technica lInformationCen te r(DTIC) 8725 John J.KingmanRoad,Suit0944 FortBelvoir,V A 22060 - 6 218U.S.A.AD#:DateofSearch:13February2 0 0 7 Record Summary:Title:Lubricat ionofclockwork fuze mechanismsforbombsCoveringdates1948 Availabil i ty OpenDocument,OpenDescription,NormalClosurebeforeFOIAct:30 yearsFormerre ference(Department ) TNARM 4 0 7 HeldbyTheNat iona lArchives,Kew

Thisdocumen tisnow avai lable a ttheNationalArchives,Kew,Surrey,United Kingdom.DTICha schecked th eNat iona lArchivesCata loguewebsi te (ht tp: / /www.nat ionalarchives.gov.uk)and found th edocumen tisavai lablea nd re leasabletoth epublic.AccesstoUKpublicrecordsisgovernedbystatute ,name lyth ePublicRecordsAct,1958,a nd th ePublicRecordsAct,1967.Thedocumen thasbeenre leasedunde rth e30 yea rrule.(Thevastmajori tyofrecordsselected forpermanen tpreservat ion a re made avai lable toth epublicwhen theya re 30 yearsold.Thisiscommonly referred toa sth e30 yea rruleand wa sestablished bythePublicRecordsActof 1967).ThisdocumentmaybetreatedasUNLIMITED.

Lubrication Clockwork Fuze Mechanism for Bomb UK 1948

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