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Ue So NAVALTECHNICAL MISSION* INe EUROPE

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npo?s No . 491-45

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C::.XiaI C.L . I?y .r"TZ::S

Seztumbs- r 1;45

DSCISSIFIBD .T_'-'-'"

DOD DIR 6200 .9

IDTICELECTE

AUG 2 1984

DWCUiSSIFIE9

DISCRIBUTIOI ST;-,TS-.:r I.T F+

Approved for p, bL-- ietaase;

84

OS -Distributicn Un.iinited 15 546

Reproduced FromBest Available Copy

S ,* NAVALTECHNICALeMISSION * IN * EUROPE

DISTRI3UTI)II Tot

U . S , NAVAL TTMMICAL MISSION IN EUROPc/o Pleat Post Office

New York, N.Y.

Me :

A9- "16 (3) (40/Hn.)

Serial : 01182

29 September 1945

From :

Chiof, U .S . 11aval Technical Itission in uurope .To

Chief of Naval Operations (OP-16--p-) .

Subject :

U.S . Naval.Technical iiiission in Europe TechnicalReport No . 491-"45, Gorman '"idchanical Timu 'Fuzes- Forwarding of .

Enclosuros :

(A.)

(H , i) Ono (1) comploto copy of sub loci: ranortan listed in distribution .

(I3 )

(H' :') Ono (1) sot of nog«'uivos of photographsin sub joct ronort irith co-,y No . 1 as listodin disIl- ribution .

1.

Enclosures (A) and (B) a.ro forwarded hcrowith .

2.

CNO (07-16-PT) is ronuostcd to make comnloto addit-ional cohios of ',..!Zis rc;Port for forwarding to such othor agoncicsas may bo intoraot.;d�

c , 7,)

0R--16-I)T )

. . . . . . . w/X7nclosurc: 8

, . . . . .

Corjy No .

1FIAT .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cony 110 .

20Lice of 'Rosoarch and Invontion . . . . . . . " . " Cony 1,10 .

JvX0.'ll`iflvr:u "" . . . . " . . .

. .. . . . . . . . . . . . . . " . . . . . ". Co"y 140.

4Co^J1av,u for AI-ilralty . . . . . . . . . . . . . . . . . . . Cony No .

Con No.BuOrd (Rc 2b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ropy 1108 .1-xvT .:cltis_iu

(i .aiSl Ftl,:.X 1

" " . . . . . . . . . " " . . . . " Cony No .

. V . IiON :SINGERCant . U. S . IT .Acting

NTIS GRA&IDTIC TABUnannouncedJustification--

ByBy

M -7Distribution/_Availability Codes

Avail and/orDist I Special

M

REPORT No . 491-45

GERri;LIT i'MCFJLITI= ^IIm FUZES

SUIIa -$Y

T . , rurrost cf t .-is investi- " : ,,tion was to discovt r the trendof dcvoln, m, :r.t ;nd- dc!si ;-n cf .r uch-micn1 Time Fuzes . Essenti .̂llyonly two of seven :rroduction -nl, ,zts contribu,ed now ideas on thesubjc - ct .

The trt. nd in dovt loo:nt:nt r .r,y be chr.raoterized as asc rcX. for me ns of srttim , t':c, fuzc in the X= b :: ..rrF1 ^nd thelatest desi :ns show - dencmd for dual -, urnoso fuzes as well rsa dt :sirk. to make the fuze independent of t} .c s-oin of tiaenrnj( .tilt , .

SepttX, :brr 1945

" 'X. AUG 2 tX

T

OF COYT.';NTS

Page

1 . The Krupp Ty,e Mechanical Time "Fuze . 3

2 . The Jundinas Tyne Mechrnical Timo Fuze . 10

3 . Combined Mechanica]. Time ^nd Impact Fuzes . 16

4 . MechozivLl Time Fuzes Devices forEliminating D,:ad Tine . 27

5 . Hiscellrny, 42

Appendix I, Forms of Germcn Time Fuzes . 47

MIL-AT 1 MSIC.&L TI:T FU=- 03

1 . The Krupp TVs Mechanical Time Fuze .

(a) General .

The Kru- ,p tyne Mochnnical Time Fuze was improved during theWnr years . The design of this Raze lands itself readily toixdrxtn.tions, some 30 being Down, most of them unimportant for,the purpose of this report .

(1) Description of Zt .Z,5/30,

(2) Safoty Devices .

Referring to Figure 1, the clock is operated by amriin spring a4pted to rote.tc a central hollow shaft which iselotted to accommodate and in turn rotate the Firing ArmRetainer (1) .

The hollow shaft contains e. helical spring,co"ressed as shown . The F, A . Retainer is held nacially againstt:ae cormrcssod spring by nn Annular Ring (2) which is integralwith the "4justa blo

(hp .

The F . :a . Retainer is held in its zeroposition by :L St:rn.r (S) ,

In opcr tion, the; Cap is rotated,by the Raze Setter,the desired number of degrees whereby the firing slot is movedto the required position .

As the bullet is fired the setbackforce dc.pressus the Se fir (3) , the F. A. Retriner is ^ioved counterelcokwiso held in its plane by the nrinul,--.r ring (2) until it justpasses the firing slot projc;ction (4) . Tho F . .,� Ret -Aner isncXw forced forward by the Sprint (5) relerLsine, the Firing Arm(6) .

The Firing ium, rotri.ted by the wring (7) allows thv firingPin (9) to rotate . The projecticn (9) on the firing, Pin slitsoff the acne shrpe Gudp(,cn (10) urged by the Spring ( 7) and firesthe, primer which is loc,Xtod directly bc,ne "-.th the Firing; Pin inthe Body (nc-t shown) .

?Mile the : r . . . . Ret :_ancr (1)

is in the

zero positionit is stopped fr-n rotating by set b,!%ck seas (3) and retained^axially by Bracket (13) . It is thus possib?.,c tX sot the Fuze

1 . (a) General (cont'd) .

by rotating the C . ,p with.its annul,-":r ring throughout 360° withoutfiring while in the Fuze setter .

The Blocker Arm (14) prevents the Firing Fin fromfiring until the Fuze is rotated at about 50 E .F.S .

Above thisspin the Blocker Arm rotvtes, against e: spring, to clear theFiring Fin.

The Fuze operates freely and may be handled andassembled to the Round spfoly . It is waterproofed externally withwax but no dessicant has been used within the Fuze to absorb theremaining moisture, .

The two wedges that lack the cap in position atsetback gverc ,.to -tt about 2000 g. estimated to be just before therotating band engagus the rifling in a gun similar to our 3"e.nd the setback scar releases the aiming mechanism at about twicethis volue . W cx-4Xct thvt the cep with Its firing slot will stAyin the set position, nzd not twist, due to the high angular accel-eration experienced. when the rot--ting band engr.ges the rifling .

c:1lyr

The escapement Lever of, for instance, a 30 seconduzc, 'hl:s a frequency of 1X2 cycles . The clock is started redthe-. r- :ttX of the rscrpement Lever is observed stroboscopically .The effective part of the Hairspring is made longer if the= rate istoo iAgh %nd shortc;r if the re.te is too low . If the+ limit of%djustmont is retched and the rate is still too high anotherEscapement Lever is mounted ; if the rate should be too low the twobrass weights on the 2scapenent Lever are reduced in weight there-by reducing tho rotary moment of Inertia and increasing the naturalfrequency of the system .

(3) Notos on Operation . .

(4) Notes on .Ad3ustment,

The fuze is adjusted -nd tested for timing stati"-

OOITF'IDENTIt1L

s

1 .

(a) General (cent " d) ,

CQWFIDMI"

It is noted that only one end cf the Hairepiring issubject to adjustment . The EscapAment Lever is mounted to thatit con be replaced without tearing down the clock nd the escripe-mont wheel is readily adjustable to match,

The clock is * testod in ^,fixture for elapsed timeby comparison with a seconds pbndulup . An electromagneticroloase for the pendulum is synchronised with the steaming cf theclock . The fixture simulates the annt4ltr ring in the cep endwhen the F . A. Ret-inor is reler.aod thrrugh the slot in the jig#r~n electronrXgnetic brake stops the pendulum . The elapsed timeis hold from .05 to .1 seconds for 30 and 60 second Fuzes- in thefactory .

.

This system of e.djusting rmd testing is samewhatslower than the Electrc:-nic &tits Testing System used in ..mericanfnctc-rios .

Tharc: is nc cbjecticn to t; sting the clock staticnlly(i .e . . act spinning), the error due to eentrif`ignl Force' on theHairsroring is subst " .nti,ally e c( :nst nt,,' rathrugh a differentconstant for c-ch rcl.nge of shin .

(5)

)n- D ,si r:;n %,nd Production .

Evalu!stine the basic dosi6m of the 'raze we note thatthe clock is she rt a::ially because the -Prim(- ;r requires nc greatFiring-Pin velocity . This allows the desiglaer tc plr.ce the clockwell t .,. the: re c.:r in the Dody and the assembly beecmes more rugged �The four plates are securely held together with three throughscrewswhici)

re nls-) used to bolt the clock to the bcd.y making, r.subst-.ntial assembly . The running frictit n h,-.s been reduced byusinf only .3 gears c%nd by rmking the e$capoment wheel very light,

The ri%in spring is highly stressed, cz crrtnonpr-ctice in the design of clocks %nd. c^used m^.ny rejections dueto bee^.kf .fe . It is estimated thra 18%, ,)f Krupp type Fuzes in_.fricn were ino,)er:ptivo due tc broken nnln springs .

The osc-"ncnt is self-stnxtinE !W. there- is littlediffor , act . in torque required. tc , stc;rt ,and tc - run . Thc mothnd ofccckinp, the firing, pin is nc better th^.n th,--.t useca, in othormec_ti=ic1A Time huz , -s .

The idcr . ! f acprxaing the two elements

1. - ( r0 - General (c(.-nt'd),

which initiate the firing, i .e� the F_.

Retainer find the Slrtin the -mules rinr-, instead r f mounting them in the srzae unit isvery nc.or practiet., The setback rblease scheme is fair.. There isnt) need to trke up backlFah in the geRrlorain . The design lendsitself to variationu fc;r special purposes as we shall see below.The w: rkno.nship is excellent,

The Krupp type mchanical tine fuze was improvedover the b%sic design by Gebruder Thiel, clock rend watch rwnufao-turers in Thuringia .

Four rlants produced f.'fioroximately 15,000dt.ily ur, to 1942 . Subsequently only two plnats were producingthis fuze fit the r!,,te c.,f ::brut 7,000 daily, Thu fuze describedcc;st the GovNrnnXXnt 10 rXr?-s each,

(b) Delayed Arming Time Fuzes .

(1) Des crirticn .

?vferi .netX is nar_c t^ Figure lf.,

Item 2 is thec-nnulrtr rink.- in which the firinz; slat is looted, A similr'.rannulus (3) with -n rrnin ; .; slot is fastened t- the trp plate of

clack .

^.rvin, : slat is (f course quite similar to thefiring slot, n1th u,7J,: tht. functic.ns of the two slots aredifferent .

Assunint:- that the clock is stnrtad by the setbackforce, the- =irinr-, Arm Retainer is n^w kept in its planc cXf rX)tvtionby thi: fixed annulus until it rt-aches the arminr ; slot when it isforced frrward :-,-ainst the Xtidjust^.tile annulus . Continuing; torotate in this now >>lane, the Firing jxn Retainer fine.lly reachesthe firing; slat and the Fuze fires .

(2) CrnnX:Xnts .

001T.JDENTI .Z

1nv "Xcheme was used in Fuzes f:;r 380 mm and 406 amruns . In such large caliber 1;une, t : -, c, l(jw setback force requiresthn.t the gel( P.sc Svar is s< .t t .̂ :-pt rrttc, -it about 601% c:f the v.nluefr.r snaller cf.libcr tuns . The Xe3gyed arming is an additionalsafuf;uard e,X ;ainst rrenatures , me. will advntee. f " r longer timesettings . rX:r inst-.nce, if we decided th^.t wo w" uld nrt want tc,

l, (b) Dc;laycd XLrninF.; Time Fuzes (eont'd ,wr, ,

set the: Fuze for less then 10 seconds time rind that a, time Pslank; as say 40 sccf ,nds was desired . By using the above describedconstruction our opportunity for accurate timo setting would be1/4 cr 25% better then if we were tc use the ccnvcnticnr+.l methcid,

(c) BB, listic Tests,

COPTFIDENTI:LL

ti few ropcrts c,f ballistic tests have be a>me avuileble,Figure 1B shows test results on 5 sec� 30 see . and 45 sec, Krupptype Mechnnical Time F'uzer .

In ccnnecticn with the test on the 45 sec, Fuzo on December12, 1943, the statement was made (by O,K.L,) that the 45 sec,Fuze was entirely useless . It was th :-,ught th:.A the errcre wereduo to Cap slippage _W extensive tests wore made using Fuzesin which the ce'just, .ble caps were fastened to the Bodies, by necuisof screws agpinst ether Fuzes with Caps having stenenrt torque .No grecA differonee w;is found. Six m^nths lator, the situationwith ruepect tc 45 sue, Fuzes hoc? irrorc-ved .

0

3 6 9 /2T

FIG . IA .

BALLISTIC. TESTS.

iS 18 aX 27

kst fir-/Y 19 4JO see. l'?mN. Tlyr FXzff

ztz s/.X

Tsf - Au

l8-?O, l9W5,wc l7ECII TIME FUZE zfz

SX

1/0 26AX1 Xs .

` Vo 29w

Jil -aoA= Asl`f;r 22-`m, loo*.

8= *re

DEC' . /2

,

XSseY. /'1R?y. Tll'1f FXJ2'E

zfz sXXo

(r) General,

WNT1Ja.1MIsaL7 - .

The Junghans. Tyne-Hechrilicx:l Time Fuze- ,

Distinct fry ri the Kr=p type fuze, which as we hive seen incper^.tad by r~ mainspring, the motive power for the Junghans typefuze clock is derived from centrifugal farce, The Jungbans fuzewas used in large qurntities , during the entire war . It is describedhere because the centrifugal. drive and the firing mechanism werec6upletely redesigned just prior to the war,

(b)

Descriptic, n of Fuze Zt . Z 130 .F ,.. .

.

Figure 2 shows the firing mechanism in the arned nzd fired.prsiticn . The timing disc (1) rotates clockwise with its firingslot into which the firing arm (2) is mcved thereby turning itsshaft r_xirlly. The plate (3) which was held from operating bythe firing arr. shaft can maw rotate outwards through the slot asin6ientef.. in the figure, The plate (3) is fastened . t o an auxi-liary shaft (4) which therf:frre rotates with the elate, Thelower fh .ztened pcrti,-n c.f the auxilirxy shaft kept -the hookshaped sear (5) frcm disengaging the primer container (6) untilthe auxiliary sh.-- :ft turner? c:b-ut its axis .

The sear now rotatesoutward, the primer cX,ntr:iner thereby released --.oves town-rd thefiring pin (7), The aoticns cf all members described are derivedfrom' centrifugal -force nee? are sh^wa in the final fires? positionin,Figure 2E,

.

Earlier in the war a flat spring was pl red. between the primercont -aner nnX the plate where the helical spring (9) is new shown,Tie phase wee to augment the ration of the primer container toinsure; firing but ihfle contruletion' we.'s found_ to be dangerousand. the . spring was revlaced by. the weak helical spring ahcwn toprevent tho,primer container from rattling .

Figure ?'1 shows the centrifugal drive red n_ bottom view ofthe clock. In the .botton view (1) is a safety elate urged intosafe position by spring (2),

Innediately above the safety plateis located a set b..--.xk pin (not s . . -wn) with a hemispherical mintbearing on the,hole in the safety rlnte, mrking the arrangementbore safe, 'The escapemett is released., to start the fuze clock,by the set brX.ck pin (4) which is held. in position by spring (5),

-10-

00le'FIM"IAL

IL the top view cf 'mfrs 211 is a nwn the centrifgollyoperated erive, The weighted gear secure (1) operate the centralrin1c-n (3) thrnugh the two pinions and ge-tre (j), Beneath eachgoes sector in located r: weak hairpin sha-ped spring to urge

.the sectors towards the periphery of the clock . These springsare too wonk to contribute mw nrhreeiable force to the drive butmerely koop the gear teeth in eontnet do ewc10 backlash in the geartrain . The gear sectors (1) are slotte6. I's shown at (4) to takeun, y1oldably, the shock of the angular rdeeelerntion exrorieneed,when the routing bind of the bullet ontoro the rifling of thebarrel .

In a torn gun the v.X.lue of this acceleration is ofcensidernblo magnitude due to the run up of the projectile .

-lthcugh not ehcwn two stops were provided to prevent thehairs-+arinp from bas Fddn#; or taking; a set at the moment of maximumangtitlnr meooleraticn.

The steps are of cc urea arranged so thatthe hairspring rzy operate freely at all other times,

:irure 2H s -we a _riot of the available torque cn the central")inic;n .

(a) Notes .

The fuss! clock is rcpul:- tci. by ,-bservation of elnpoec! time,The rogulitinp- mrehino has a aeunting fixture for clock containingtwr electric contact members which are turraneN-d so th,,,.t one startsand tho other st , ps a master clock .

The fuze is nl::eod in then-ant end rotated at 16,000 R .p J( . . contact riember 01 holding thevsc :xpement lever tc prevent the fuse clock frrm stnrtinP until itr, f.cLos the eesired velocity, whoreupcn rustuatod by the oentrifuRalf ace, the c nt^.ot croaals to str " rt the fuse: clock ^nO the masterclock simult :nocusly, The timing disc has previously been setnt 30 sco-ne.s rnc'. when the fuse clock fires the r;uxiliary shaft(4) Floaro 2 ,)perr4tes cr.ntact rn nber #2 t- st .)n the master clock.The elrneoe. time is ro ;td and nfjustnents -f hatrsprinp length areru ec, if nocce®n.ry, t- secure satief etrry 1 -rerntic:n .

They Jungh-ns tyre+ fuse was n . ,Ce in ccnsider,bly larger quanti-ties thrtn the kruoo ty "e . It to estinr.tee that -tb , ut 250,OM unitswar.:_ mne.o tit mthly f r, n 1"37 to 1942 .

From 1942 to 1944 the Kodenk

2,

( c)

rT

tea

(c: nt' d) .

factcry chenged from Krupp to Junghens fuzes adding aaXther100,000 units per month to the total capacity frr the manufactureof this fuze .

The Trice tc the Government was 11 marks for the ZT . 2, Fgand 1.4 ra-rks fc:r D(;pp Z S/6U pg .

COITEIDEYTI.z

O

Ease I : pct Unit .

ICOYFIDENTIAL

3.

Combined Mechani cal Time P,nd Impact Fuses .

Apparently the need for an impact detonating element in themeeh,nieal time fuze becom.. acute in the summer of 1944 . Threedistinct kinds were designed between that time And march 1945 .In chronological order wo havet

The Krgpp Type Base Impact Unit with severalminor variations .The dunghans Type Point Detonating Unit withthree variations .The Skoda Tyre Point Detonating Unit withfour variations .

This unit dptes from July 1944 and -is shrwn in Figure 4 .

Itsuse w:-.s c-. nfined to Krupp Tyke Time Fuzes .

Referring tc Figure 4a Plate (1) serewthreaded into the body beneath the Fuse Clock,c,rri .:e a fixed firing rin (2) .

Recessed in the body is acylindrical princr h ")using (3) retained, in the static position ofthe fuze, by ccnvuntional clapper style detents (4) . An anti-creepspring (5) bears ageinat the primer housing .

The modo of ,^per^.tion of this unit is obv' ous .

Some variationsare provided with longer bodies admitting larger primers . Thecombination was known .a Dopp .Z e/30, Depp Z a/60 depending on themaximum running time -,f the time fuze .

(b)

"Jungfrau" Point Detonating Element .

Ge'oruder Junghaus developed throe quite eimilcr point detonatingdevices for their mechanical tine fuse .

(1) The. first design, known as Dnpp . Z S/6o Fl, hPd ag6F:r arrrngement for Xxning the imptct unit some distancebay-nd the muzzle (,f the gun (Maskonsicherheit) . Somethcusr.nds were nade for O .K .M. at "hessap", H=burg. Itwas less sensitive th_°:n desired.

( ."-_) The aocond design, kn:)wn ea E . Dopp Z S/30 operatedlike "Jungfrnu" but had two hook. shpped centrifugal' detents

-16-

CONFIDENTIAL

Jun frau" Point Detonatin&,dement cont!d),

for the impact firing in. Premature enfety of the imractunit Makensicherheit) could be-varied by

,e, step for the

impact primer which was operated by the nunb6r 4 gear in thefuzes Clock . Approximately 66,000 units were made before thewar ended .

(3) In reer nee to a demand from the O .K .M. for greatersensitivity of the irTmct unit the OJungfrau" was developedrjzd submitted to O .K .M . -B Febru= 1945 .

Very few were madeetnd acne were 'used in Aetuz:1 warfare .

Description .

The impact firing pin (1) -:nd the centrifug l detent (4)Figure 5 xe assembled to d mounting cup which is threadedinto and adapted tc be rntat(d with the Cap. This mount'cc - nt, ins ales the hanmer a'r,ring and the set'-pin.

The firingpin (1) is provided with a collrar (2) ec,, that 'it ban be heldin a, safe :ocsition by the centrifWAly operated detent (4) .A lieit helic%l erring (3) between the center shaft of thefuze clock -,nd they firing rin eloovc he>lds the firing pinin position while the; bullet is in flight .

The detent (4)cper.ates aplinst the spring (5) .

In the number 6 plate ofthe fuze clock, is ruceesee a nrimer slide (6) which is heldcut of line with the firing pin by the spring (7) while theclock is stationary . It will be observed that due to therevised Junghaus drive, making the central pinion shorter.̂nd larger in diameter a fair sized h(lo can, be drilled nxinllythrough the pinion to accomodate the firing rein.

0peratinn .

The operatitn of the impnet element is shc-.wn in Figure5, the 'primer fires through the fuze clock into the booster .

(c)

Skoda Throe 'Point Daton, .tins Unit

(1)

Goner a .

During February 1945 a-,point dotrnating clement aea unitary structure w: ,.s devisee? - .nd t, sted at the Skndr. Works .

-1 7-

C017ID.TFTI: 11

1. (e) STcoda Tj=e Print DeV.nating Unit (cent! e?) ,

It hrd tw- rc?v:+ntnges over the nevi " usly described units . Firstit w. ,.s more sensitive:, second it could be very simply adapted. toexisting Zt . Z . $130 time fuzes ;f which more thr,n seven millionwere av:^Jlable . The O .Y .N. nuth,- razed the conversion of existingmechanical time fuzes to,Skoda CC Z s/30 on 14 March 1945 as atempcr^ry mer.eure, the ultimr:te in sensitivity not having beenfound as yet,

(2) Description,

Referring to Figure 6 it is observed that the CColemc;nt (1) is mounted in the car of the time fuze no a unitarystructure . 11 relatively lrrge charge (2) is adapted to be ignitedby the sensitive primer (3) , The sensitive mriner is urgedtown-rd the rude by the spring (4) but is hold in safe, position bythe firing pin (5) .

The firing pin is held in position by thespring (6) ' ,.rd the : ball' M-

(3) O er, -,t ion,

TX :c.: . unit st,-:rts tc arm when the r,und is fired,the set b .ck fcrco :acting cn the firing:pin compresses the spring(6) ^.11owinE; the ., 11 (7) tc : frill out into the wide part of thehousing (9) .

:after the bullet is boy, nd. the accclerntion fieldof the gun, the firing pin is urged f .Xrwnrd by the spring againstthe dashpot effect cf past^n (9), the complete rrming being thereby retarded for e. distrance, said tc be - frcm 15 to 150 feet beyondthe muzzle . The sensitive primer is n w free to mt,ve into firingp:sition . Upon impact the charge fires through the fuze clock intothe bX.oster .

(d) Johrinn-Super-Zundwerk.

DescriutIc n .

I`itute 7 sh -we ^. design whi eh st mewhat resembles the, Skcdaunit in that it could. rc!f;dily be applied tc existinp, time fuzes .The firing min (1) is r ,_t ;;inee in the un .̂rmed nositicn b : - n detentsystem consisting: of ^ nct0hee T,lXXte (2) r.nd rn -luminura sriral(3) . Bet , :oen the firing min cane. the -vrimcr is recessed P. centri-fugally eperc:tec! safety slide (4) . The cmerr.tion of the fuze isclearly d.iseornable by in5-,,ection of the rirure . XX*nother very

_1 9-

3. (d ) Johann-Super-Zundwerkl corit 4 d

(e) Notes .

OM17IDBYTIAL

similnr .versicn of the fuze is shown in Figure 8 *Xna it thirddevice, not shown, and no model, was also made owing to theurgency of the project,

AV

No, 2 fuse, rigwre S ; was ready first and .40 onM-ples were &Asznd tested. The ballistic tests were s.ztisfnctory but the designwas rejected, not being mr-isture proof . No . l, Figure 7, of which240 a<imples were tested was Rpproved .by,tho O .K .M.

Tests were mado for sensitivity,at reduced velocity and boththe Skoda end the Super Zundwerk fired at Vo 4 feetsecond Xninst 1 rim Duhal or 4 no cr.rXdbcr,

perrd . The premature safety(naskensicherheit) was abt)ut 30 Poet beyond the muzzle, more

definite with the .aluminum Sp-ral System then with the " potsystem (no in Skod.a),

These fuzes were tested about Nareh, 1945 and none were actuallyused in warforo,

It is worth nc- tank; the st .`Aenen,Xs cf a PW, relative to theefficacy of the Cc-mbin :ticn Fuze . In a report issued by the Officeof the Director of Intelligence,'liq,, USSTAF (Rear), 5 June 1945,Walter von xthelm, GonerU der F)akartillerie, former inspector, general of flak, was interrogated relative tc Puzes among othersubject$ .

"In the latter period of the war, .olanes were se wellcX : ,nstructed and armored that IM projectiles hX..d to burst within 4meters of a plane to be effective ."

"It was calculated (on probable errors) And c0nfirMed experi-mentAlly thca a 4-motored plane such as B-17 o." B-24 woule. receivea Oireet hit once in nbcut each one thousand rounds fired ."

"This fuze was develmed tc burst cn iripaet c.nd if contact wasn,ot mAde on a nlune, then -c-,,n time cs with the customary time fuze .It wc.s very successful !,.nd ner algae, dropped from 3000 rounds withtime fuzes tr, 900 round with this Fuze,"

"This fuze went into prcdueticn in the f ":11 cf 1944. InOctober, 1944, prcducticn wra 1800-2000 fuzes and this was tc be

3 . (e) Notes (cent' d) ,

CODTFIDENTIAL

inerev.sed rrpidly until T>rcducticn of fuzes would be of this tyne ."(

u7ted. verb ytizl . )

The fuze referred to. is E Dcpp Z S/30, the Immediate precursorof "Jungfrau" (See "Jungfrau" second design above) .

- 'o c n readily see how both of these figures far numbers ofrounds would have been a ,?'eat deal smnller had the GermanssucceXXIed in developing a good mech,!tnicA.l time fuze, to be, set for"tine to burst"while in the h-un barrel, thereby eliminating thedead time as will be discussed in Part k,

X^XXX..XXXXXXX .XXX~,nX`

.e

L",

I

\

ON X

lwlow

evil\\WXX. .- y

-'y

v

Xnlai

INS

I ; "Nsor.ri

rgX

INlX

;

Xl'M k

f

v

(1) Genera.]. .

CONFIDENTS

Mochanicul Time Fuses ;Devices for SliminntiDs!d Tiaw,

The mechanical time fuse has ah inherent possibility ofaccurE.cy far beyond that of any rther fuse known to date .Unforturiately - present usage permits a variable error between the-,)rccoss of setting the fuze for "time to burst" and the actualfiring; of the gun. This variation, amrXunting to maaay times(10) any timing error existing in the fuse itself, obviously makesthe fuse much less useful than intended.

Both the British and Grrmnns have tried to develop devices tocliminnte all or part of this dead time, and while none of thesedevices has been used in actual warfare, nevertheless the subjectseems sufficiently important to warrant a brief summery of whathas boon done to d.=A-te,

(c:) The 1'iidgeley Time Fuze .

-27-

Tho idguley time fuze w¬.s Aevised and constructedby the Midgolcy-Harms Or , . . Ltd., London about the beginning of thenwar . 3t has 'hewn t-ffered t- the British Government and it issaid that while the British ?1f,vy ash,-;uld like to have it made insome g%antity, the Government was n ":t in a rosition to assign theneco s sary we rkmcn

to the con?,nny.

. Toe fuze was designed tc be set for "time to burst"after the round has been rammed, by ac%-ustic means, Na actualfiring tests have been rice but the fuse r4nd associated gerx hasbeam found to aperate satisfactorily in dummy trials .

(2) Descri2tion of the Fuze .

The standard Briti .ih neeLanieal time fuze is of theKrupp typo described_ in Pnrt 1, in which the firing arm contPiner,after release of the set back arm rotcttes counter clockwiserostrainod in the rlnne of rotation by an annulus . When the firingarm container reaches the firing; slot in the annulus it movesr=in11y rcleasirk ; the firing c m which in turn releases the firing-in .

.

00)WIDBNT14

) The I11dgoleZ Time Fuze (cent!+:,LIn- the Midgeley Fuse shcmi'diagrammatically in '

, iguro 9 we have a standard fuse clock (,1) . and-also at auxiliaryclock (2) which rotaiee tho aanulue.O) . 2t will be recalled thatin the conventional Krupp type time fuse the firing slot is locatedinan annulus which is pXrt of the can and that the "time to buretsis set by rotating the_cap with'.respeet to the body thereby placingthe firing .siot in tho annulus * in-the desired geometrical .rosition,In the' Midgoloy' fuze the annulus with it's firing slot, ±s constantlyrotated by the auxiliary clock. The appropriate geometri"Iposition of the firing slot becomes fixed vnly at firing of theround when the set back force will cause the annulus to beimpinged upon a numbor of fixed sharp pins .

Into the body ii secured a reed (6) and on the rimof the annulus is affixed a i::luck (5) in such a way that for ertchrevolution of the annulus the pluck strikes .the reed Xo emit asound ; As embodied in the latest model the annulus mckes onerevc lution per soer.nd vne. tho reed omits a 3000 eyel1P note eachsecond . Becouse the position cf the pluck with respect to thefiring slot in thc,r=ulus .i s fixed, the 3000 cycle note defini-tely jocntes tho firing; slot distance from the zero roint cf thefiring arm ccnttcinor .

In operrticn the round Is picked up, pin (j)manually depressed. t o start the auxiliary clock and the sound isrammed . The rim c,f the eurtridg,:; ctlge, (see Figure 0) makes

,.physieel ec ntr..ct with the projectiag ,part of a microphone (11)which is fastened to the breech end of the gun, Bvcry soundomittod to now picked up by the microphone, amplified and filteredto oxcludo all but the fundamental of 3000 cycles .

On to the dial of the predictor (16) is affixed onec,.ntr ct X.nd %cth, .r contact is fastened to ",'rotating arm (13), bothbeini, in the firing; dircuits . Rotr.ting txn (13) is aerated to berot ted through n. friction erivo Xy means of a synchronous motor,turning ono revolution -nor second, rrecisely like the annulus inthe fuze . A relay (12) servos to h - ld tho arm Pt tho zero ntsitionag%inst the friction drive as illustrated in,Figure 9 .

The round. i s in the s and at the first 3000 cycle

(1) Gen::rnl .

COMIDOTIAL

,Ja) Thg HdgX

ley Time Fuze. ( ,cont l d) ,

signal picked up by the microphone the relay is actuated, releasingthe rotating am . The contact on the predictor dial'can be adjustedby the fire control gear up to the time that it is desired to closethe firXng pircuit p41ae'whe^re,- whereby . the contact-'on the dialbecomes- alive and when, nest , it ; is - actuated by the Mating armfiras the guA. . . . .. . ..The rotating!XaXus having, been - synchronized bythe 3009 cycle note . operpting, the; releq, -the fuse ie evidentlyact for "time to burst" at the instant of cpntrct4 To achieve ;u high order of nccuracy the auzilinry clock has an eacpamontfrequency of: 700 oycles s%nd is well designed .

The running time ofthis clock is 30 seconds, thus thb round meet be' fired within'this timC after the clock ltas been stnrtod,

" .

This aiathnd- of ellmin4ing; aetd time has a number,c4 drnwb#Acs which are immediately scppi-re4t, as well as introducingin itself nn urror l-,rger than the one it intends to eliminate .

It . mF,v be mentioned hire thA,t nttempts were made topick up thin sound . without metr.llic connection but it turned outthat ever a slight coating cf grease tends to attenuate the 3000cycle mote so the t it com-nietnly masked by rendom noises .

Thenecessity for met^llic connection sev(rely limits the utility ofmethod.

It will be observed that the present arrangementtakes no %ccount of the time elapsing between ecntact in the firingcircuit and the actuat,set bank which locks the annulus in place .If this time lapse is, say . .l .seGonds, .the annulus obviously mikes ,.1 revolution or 360 whXeh corresponds to an error of more thFm3 saernds in this fuze.

(b) Mechanical 2-clock I'uzc .

The idea of setting the mechrnic .̂1 time fuze for"time to burst" with the round in the gun barrel wn,s 'proposed bythe OeK,L . nbnut the cod of May 1943 . Both O .K .L . ^nd O .K .M .were anxious to have this work progress rapidly and,two laboratories

-29-

(2) Descript4on . X

00WIM11TIAL

4 . (b) Mechrinical 2-clock ruse (oont'd)

weru charged with developing, independently, the desired device .

The finished units turned out to be very much rtlikein principle and only one needs to be described,

Referring to Figure 9, c: June-Lens Fuse clock is shownPS (1) .,ad directly above a time set clock (2) adapted to rotatethe, timing disc (3) of the fuse clock at 1200 per second for 30seconds, Figure 92 shown the methc.d of operation diagrammatically.Just before rn ming tha-round was placed into a cup - (4) and thetime set clock stprted by manfully depressing plunger (5),

Theoperation cf plunger (5) also made a circuit which releasedrotn.ting arm (6) driven by a meater clock at the some velocityno the timing disc in the fuze clock, and affected %ynchroniem ;Firing relrq (7) was mounted on an annular ring and positionedby the existing fire c(ntrr-l gear. The method of operation isclearly discernible from the din.gr:ua 9A.

(3) Plates .

Tt o Krupp scheme woe retiAy first and wr±s tested inMarch 1945, While the 1:lbcratnry tests had turned out well theproving ground tests were unsnt isfactory,

The fuze was known-is "Im Rohr BinstaellbFro Zunder Zt . Z 5130 M2n .

The Junghnnsscheme wn.s not tested .

-30--

This method is obviously an imprcvenent ever then.coustic system being more widely applicable .

The particularombodyment Xs shown would slow up_ the firing somewhat fl.nd justlike the Midgely fuze the error is of the acme order as the onethey were trying to correct, Because the timing disc makes one-third as m "'my revc:luti ,:ns per second cis thr%t of the Midgely fuze,the error is nbc ut 120 'or once sccc-nd plus,

The Germans checkedthe time lapse between contact nnd seL back. on their guns andcund that it v- .ried from .05 tc .15 seconds depending mrinly on

the temp(=turn c-f the powder . Frc>m this considsrati : , n it nodoubt beaxie obvious to them that W system with a revolving timingdisc to be locked n.t set brick wr,uld bo subject to r. l r.rge error orunduly impede thtr firing .

4, Nechnnieal Tine'Fuzos Deuces fc.,r Eliminrting Dead Time

cXnot I d) .

(c)

jlectrie4ly 'Set 146chanieal Tima Fuze

( 1)

Gemr,-,.l .

OOVFI;DlqnlAL

The development of can electrical system for settingthe mechanical time fuzo while the round was in the gun barrelw=..s Basted in 1941 In the Jungh=,ns Reser.rch Labors-tory at Freiburg.It was uriginUly intended that the system would be used for Sg mmflak but it turned out to rcquire a wire through the sound end thebreechbl-ek which was objections:ble .

In 1943 the development wasrosumod fc;r use with anti-aircraft rocket R 42 . The un :.t to bedescribed is s~ further simplificetion over the fuses actuallytested and wr :.s made possible by the ccnatruction of a high speednechnnicsl counter .

(2) Description of the proposed R:-.cket Fuze .

Rcfrrcnce is ru.de tc Figure 10 in which a fuse clockis shown as (1) having .^, cupped timing disc which is adapted to berotated at 1 RPS by ^ spring mritor,

Disc (2) which serves asgovernor is pct :stud .t 100 RPS by the erring motor, The toothedwheel ( ) 'r"_nd the e^n (4) rxe mountod on the acne shrft rs the disc(2) rind thorc1r,,ro :".lso rotate with a velocity of 100 WS .

Thusthe enn (4) makes sand brvnks contacts (5) 100 times per second,shorting out r .nd unshorting resistance R which is rlpced oleetriog11y

'across the contacts (5) .

. Separately mounted is an electromagnet (6) to thearnaturE, (7) cf which i s attached pin (9) .

By orerat ing the magnetthe pin (9) releases the toothed disc (3) thereby starting thespring motor which rotates the timing disc ( ,n the fuze clock . Thenumber of operations r)f contacts (5) are counted by an externalcounting relay and at the rosired count the magnet is de-energized,thu ^rupture drops pin (9) into " no -f ttie ten slots of disc (3)atoirning the spring mtXtor thereby arresting the timing disc .

Fi b7uxe 10B shows a diagram cf the arrangvment . Ris the resistc ,ace across the contacts (5) in the fuze . (6) is themagnet by raes ,.ns :-f w.Ach the fuze: cryn be set as c'.escribed ^ibove .

( c) Xlectricr:lly, Sef Divetu>xri,'va1: Tfthe faze ; : . j cXXnta d)

External to the fuze are contacts ll and 1,2,,whiph,are - . ,,de manuallyas shown, 12 being' the . holding. cantact'*ibis the-relay L.

Depressingswitch M starts the operation cf setting the fuze,

A plus potentialthrough resistor'D and point X actuates meet . (6) to start thegoring drive and thereby the timing . dise. Contacts (5) in the fuzeoperate and unshort the rbsistanca.It,iu the fuze thereby raisingthe .potential at X, i .e ., .the alternate high and low potential atX, 100 times per second, caused,by the opening and closing of-contacts (5) may now be ugod to sot the fuse for'tho proper "timeto . burstf while it is in the gun barrel,' The .counting circuitconsists of-a five element tube (T) the plates cf which are connectedto 'the coils a and ii on the counting relray that, operates therot:tins azxt (9) : Tho predictor sets contact (N) to the destrefposition and when the rotating A.rm (9) mnkes eont ct with N thefiring circuit is nrXAe .

In this niurticular circuit the e6netants are chosenso that when the potential at X is low,, making Y negative, the flowof current through nlr-te A and coil a stops, At this eaoment the,potential on ::c1 ri-sos area. grid 2 becomes positive .

The tube currentnow flows thrcup 'plate B 'Maid cX-il b counting another ,005 secondstep.

At each `step the rotrA ins am advances exact when it reachesN, as mentioned. abnvc, the firing circuit is made, The countingrcllV is said tc be capable of operating on pulses of,00h secondsduration.

.

It was pointed out above that the fuse was producedIn 1945 for the R 42 rocket . when the rocket shin reaches 2000RPM (some ,2 to .3 seconds after firing) the tiring disc isclamped to the gear train of the fuze clock by the centrifugullyoperated clutch shoes (10)figure Sf .' At 5000 RPM ( .6 to .7seconds) the coupling pins (11), which have kept the timing caseoonnacted to the erring motor and`thertfore stationary up to thispoint, release the timing disc which can now be rotated by the clock.4.t 9000 RPM ( .9 to 1 *ecand) the-fuze clock is started by theoper!Aion of t_ centrifugally operated release for the escapementlover (not shown) .

'

(3) Notes .

0ONPIDENTIAL. r wiYX+ XXXK4r

Because the timing disc rotates at 1 RPS and can be

0ONFIDMTTI hL

4 . (c) ElectricnIly Scat Mechanical Time fuze (cent' d) .

stopped within 1 millisecond. the inaccuracy due to the setting

mochnnisn is exceee.ingly small derendent only (-)n how olosely

firing contr.gt N can be set . The, awing drive has been worked

c-ut so that they gear trrAn between the toothed disc and. the timing

disc h!s not lost motion end therefore no error other than thatin the fuze clock itself is evident .

The fuzes were tested md rron^unced satisfactory

for the Turoose for which they were intended .

In October 1944

Junghans started. to produce 7500 units and the first 500 were

sent by truck to the lending :nXant .

The truck was destroyedby a bomb, the Gr-rm%ns destroyed t:11 Texts in the plant so that

no sanple is avail .blo .

Owing to the limited. experience the cost wns not

known but it wris said. that the spring mXXtor was much cheaper

th...,u the set clock in the 2 clock system previously described .

The fuze was known as "Zt Z . s/30 Fg' mit electrischen

einstellwerk fur R 42 (21.4 cm)" rad wa.s procured by O .K .L.

s

0 0 0 0 0 0 0 0 v w qr

M

5 . Miscellr.nv

aWUNC[ASSIFIM

U) JunX;hans Univ1rrsal Mechanical Time Fuze .

Aftt,r scLje years cf er?erience with centrifugally cperntcdtine fuzus Qebruder Jun&tans decidet.i that a much'more useful fnspcould. bG rroduceO. by using a spring drive, 'They r:%icXdod. the useof a clock mainer-ring in the light of their own and Krun?o'sc :x77orience with breakage cf the . conventiontal mainsprings. Theybelieved that the fuze should have an irm_ XXct element to make itm^re useful and. that the clock should be small to fit intosqueeze bare projactiles .,

The c'.evelopment cf this fuze, known as "Vereinfaehter ZeitZunc.er, Kleinwerk, mit Zugbrjrd Antviebu wn.s started in 1944 and afqw hundxed sermles, were made .

Twenty units were tested and f-,undto be satisfnctcry, however, the O .K .L . wanted the clock mr.de' stillsmillor but the war was over before the redesign cc. ,uld be started.Tho clock, as mfu'.e, was 32 P.m in diametrr (standard. 38) and wasdriven by two- hr1icr 1 wrings operating normal tc axis of theclock, rc.t,,.tinr the central rinicn by rioans c f a steelbend .

Aconplett; sA -:f wX rkin,, 0.r-:winF;s h,:s been fcrwarc°.ed to CM (or-i6-PT)

( b)

llech-nic .1 Time maize f cr Srin St-bilizAd Roclmts .

The "Junr-fr^.u" desire -,;reviously described wr.s revised bysubstituting centrifugrXlly opert:,,ed. elements for these thcA werecperX .ted by setbt-.ok . Ab,:ut 25,000 units were made for 21 cmdiameter rockets and 1 rger . The ogive of the rocket wr.s extendedtc, conpletely hc.use the fuze and an additional external hammer wnsnr,do to project in front of this windshield to actuf:te the pointdetr.nrtin.- element X, f the time fuze .

This fuze w " ;s known as R,Drip Z S/60 .

(c)

Self Destructi X - n Fuze. (Rotating),

burin.~ Jrnw^.ry 1945 a simplified self destruction element wasdevclcpcc. fc .r the 37 -m fuze .

Figure 1.', . sh : ws the working --)rincinleof tht; unit . In the figure (?) is rn ^.rm secured r.s shown but freetc . move outward when the bullet sins . Srring (5) is loaded bythr m "Ainn cf the r..rn . lrft,-r the srin has diminished to thedesired extent the l(4 .c'_ed sr)rin,, Xv( .rc,)mes the centrifugal farce

-42-

5 . (c) Self Destruction Fuze (Rotati ) (cont'd) .

on the arm allowing; it to move inwrrd . The closer it approachesthe center the mere rgpid is this motion and finally it firesprimer (4) . The gas pressure acting on the enlarged portion ofthe firing pin (2) causes the firing -min to fire the main primerthereby destroying the bullet,

60 units were made by hand were found to be satisf^ctcry .The design wa sent to the O .K .L . for aprrov%l gust about the endof the wnr. It should be noted thrt the aluminum spiral asdivided makes an excellent and inexpensive detent . Tests shearthat at 30,000 RPM tho bullet is safe (Maskensicherhuit) 45 feetbeyond the muzzle in the 3.7 mm design. At 50,000 RPM the 'bulletis spfe 24 feet beyond the muzzle in :-the 20 iam design .

The described unit was intonded to provide a less expensivefuze than usod prevvcusly and was called "Verimfachter 3 .7 cm2erleger" .

It was adjusted in the,factory by bending the tail eadof the spring.

The fuze it was to replace cost 1 .88 marks and the smallerfuze cc st .61 mztr!cs . The aluminum spirnle were made X n specialmachines at the rr ;te of iN ut 100 nor minute,

X" MCLASSfFJED

(d)

Self Destruction Fuze (Yon-rotatin

-43-

The fuze. shown in Figure 12 was never designed but the »roe-"pective designer thought it could? be made s(mewhat as indicated .The block (1) provided with the slotted nlato (la) is resting cnthe plate secured by spring (3) and encompnseas the firing; min(2) . y By setback (about 40 ,g) the block moves downward and rotatesthe firing; Tin.

This rotation winds the erring (4) by moving sector(8) .

After the bullet is in flight, spring (4) operates sector (9)which is slowed down by the ratchet (12) through wheels (9, 10:end 11), The self destruction firing ann (5) previously cockedcn the htalfshaft (8a) is reler.sed when the sh-.Pt (8a) has movedsufficiently and strikes tho primer (7) whereupon the gas pressureoperates firing pin (2) and. the bullet is destroyed.

FiscelltSy ( contIc'.) .

electric Fuze fur .:cllcw Che.rF;e (100 mm projectile) .

To sE-curt: the fast fuse response required for a hallow chrxgethe Germt,ns &ev#:lopod nn electrict.l impact fuze which generat-.dits cwn curront . Within e cylindrical enclosure 22 mm in diameterand 37 mm loni; was springy; mounted a permanent magnet cup end softiron ccre c^ntnining ^ windini=; which terminated in two ?Mugs .Exterinr to cup w, s xlaoed .l Y condenser . The cup was shorted,.t its open end by ^n irc:n keeper secured to the extornal structure,alt the moment of imp^.ct the magnet assembly moved. away frc:m thekeener the rr:sulting voltage (180-200 V) charged the condenser andfired a sensitive electric squib . The unit seemed tc be in thedevelopment str�ge and nc srmples are avail, .ble,

(f) Tnchogrnrh fcr Reccrdink; Spin .

Utilizing !-, nechr.nic,:l tine fuze clcck with suitable recordingr,. , int enc'. disc ennb1cd_the Germans to find the srin of nrojeetilesend rockets in fti sirrle yet seemingly sufficiently accurate wry,ti1, .rking r.rr.win;;s toguther with curves nlottec, in ^ fe%r tests havebeen forwoxd.ed t;

CZTO (O:p-1Er-rT) .

Prepared by ;

K, G. BrRGGFMT,Technician .

APPENDIX i

FORMS OF GER2UN TIPM FU ,S .

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0

s

"wss

- `_ s'4` "_ oa

tA 4i FI

"tea. H.`

,For E, cXiprehansive survOY of German Fuses reference is made

to U. e .

Te ::hnieel IMiseloh in Mtrope Technical Report I1o .

1 101--45, prre1N-ek: by Lt .(3g) R. Li Gellein, USNR.

The

aeeigns dealt with in this report were screened out

from f.

. .%mount of material anc? we:. e . ., in the main, proposed too

late to b :: .

in actual warfare .

- The material reported on here was collected, screened and e--valuatea by:

Comdr . M. L . IULTHSON,Lieut . R. T, XX.RI C4:T ,Lient . R. L . WXTSON,Lieut . P . H . C;LSTLs,-ON,Lt,(Jg) R. L . GELLEIN,Tech, M. L. KIRBY .