AMCP 706-210, Fuzes

am cp 706-210 tration. A shear wire is used to hold the pin in place prior to target impact. 12-3.2 D ELAY FUZES Delay fuzes are made so that pyrotechnic de lays may be inserted in the explosive train as de sired. They are usually in the tail or midsection of the bomb for protection during impact. Fig. 12-6 illustrates Fuze, Bomb Tail, M 9061 ,4. The operation is described in the paragraphs which follow. F ig u r e 12-S . E x p l o s i v e Train o f Fuze, M904E2 12-3.2.1 Fuze O p e ra tion raise the reliability of lead initiation (see par. A drive assembly acting through a flexible 42). A gap of as much as 0.060 in. will suit this shaft rotates pinion and extension assembly (1) case as a first trial. Tests will dictate any change. at a constant speed of approximately 1800 rpm. This motion drives the plunger release screw (2) The detonator must be sensitive and initiated directly, which withdraws from the plunger as­ by flash; hence, it will contain an igniting mix­ sembly (3) freeing it to move longitudinally upon ture, a primary explosive, and an explosive simi­ sufficient deceleration of the fuze. A creep lar to that’ in the lead. For the detonator to fit spring (4) prevents the plunger from moving be­ into the arming rotor, it cannot be over 0.4 in. cause of velocity changes of the bomb d u rin g free long. It should have a length to diameter ratio of fall. about 3:2 for proper propagation of the deto­ nation wave (see par. 4-4.4.2). The M35 Deto­ As the plunger release screw rotates, the rotor nator meets these requirements. The aluminum release screw assembly (5), being keyed to it, cup is 0.370 in. long by 0.241 in. diameter. It withdraws from the rotor cavity allowing the has a base charge of 200 mg tetryl, and a primary rotor (6) to move by spring action thus bringing charge of 266 mg lead azide. the detonator into line with the rest of the explo­ It is convenient to have the plug-in delay ele sive train. This occurs approximately 0.4 sec be­ ment contain primer, pyrotechnic delay column, fore release of the plunger. A detent (7) locks and relay. Delay Element, M9 is such a unit (Fig. the rotor in the armed position. 47). Actually, it is six different units, depending on the delay (nondelay, 0.010, 0.025, ‘0.050, Impact then causes the plunger assembly to 0.100, and 0.250 sec). The primer is a standard move forward until an annular groove in it in­ Percussion Primer, M42, and the relay element a dexes with a steel ball (8). The spring-loaded lead azide relay similar to the M6. Zirconium/ firing pin (9) then forces the ball into the groove barium chromate delay composition is used for and is thus freed to be propelled into the primer. the delay, added between primer and relay to make up the component which is stamped and This particular fuze has a desirable safety fea­ coded as to delay for easy identification. A lock­ ture. An inspection window (10) judiciously ing pin is added to the fu z e to orient this com­ placed serves to indicate whether the fuze is ponent in the proper position in order to mini­ safe or armed. The flexible drive shaft drives the mize the possibility of the fuze being inserted spindle from which the plunger release screw is turned. As the plunger release turns, the gear into the bomb without this part. moves away from the window. On target impact, the frangible nose of the A Delay Element, T6, loaded to give either fuze is crushed so that the striker body is driven 4-5 sec or 11-14 Sec functioning delay, is inserted rearward forcing the striker pin into the primer. into the fuze cavity just forward of the firing pin. For this percussion primer, the firing pin has a This delay element contains a primer, a pyrotech­ hemispherical point to fit the anvil of the primer nic delay column, and a lead azide relay charge. (see par. 3-3.1). It should be made of steel to re­ The output of this delay element flashes into an sist bending or compression during target pene­ additional relay and thence into the detonator. 12-7

AMCP 706-210 FLIGHT - PINION ANO EXTENSION A SSEM B LY 6 - ROTOR 2 — PLUNGER RELEASE SCREW 7 “ DETENT 3 - PLUNGER ASSEMBLY 8 - STEEL BALL 4 — CREEP SPRING 9 — FIRING PIN 5 — ROTOR RELEASE SCREW ASSEM BLY 10 - INSPECTION W INDOW f i g u r e 1 2 - 6 . Fuze, Bomb Tail, M906 This unit is similar to Delay Element, M9, w here r is the radius to the centrifugal weights. shown in Fig. 4-7. To release the rotor, r m ust be positive so that moj2 > k . For th e d ru m to grab the rotor, r m ust 12-3.2.2 Drive Assem bly be neg ativ e or k > hud2 . T herefore, th e grab speed is less than the release speed. Thus the The fuze arming mechanism is driven through grab speed is the proper one to use in designing a flexible shaft by Drive Assembly, M44, in the the governor. tail fin of the bomb. Since the fuze can be used on many sizes of bombs, this arrangement allows The spring will stretch because it is in the cen­ drive and fuze to be separated different distances trifugal field. Hence, this factor must also be con­ as required by various tail fin assemblies. Three sidered in designing the spring. The assembly is different lengths of flexible shafts cover the nec­ broken down into parts, their masses determined, essary range of bomb sizes. and the centrifugal forces calculated, to deter­ mine the initial spring tension. The spring is de­ The governor is the same as that in Fuze, signed as discussed in pars. 10-2.1 and 10-3.1. M 904E2, Figs. 12-3 and 12-4. A close-up of the governor is show n in Fig. 12-7. V anes spin the 12-4 TIME FUZES internal drum w hich engages one-piece die-cast alu m in u m w eights. A t the p ro p er .speed (1800 Time fuzes may be used to function bombs in rpm) the weights disengage from the drum under the influence of the centrifugal field, thereby WEIGHT preventing further increase of output shaft speed. The governor spring is made strong enough to hold the weights in contact w ith the internal drum at the desired speed. Note that the centrif­ ugal force upon the parts increases as they move radially outw ard. The equation of m otion for these p arts a t a constant spin velocity o> is (see par. 6-2 for term s) F ig u re 12-7. C on stan t S p e e d G overnor o f D rive, nr = (ma>2 - k ) r (12-2) M44 12-8

AMCP 706-210 the air. An explosion above the ground creates ejected allowing the firing pin (2) to move for­ an area of greatest lethality for ground troops ward out of the slider cavity. This motion per­ and for soft surface targets. The newest fuzes use timing devices for both arming and func­ mits the T5 movement assembly to start. Simul­ tioning processes. taneously, the vane (3) is freed to rotate. Then 12-4.1 ‘O PER ATIO N (a) ARMING IS ACCOMPLISHED AS FOL­ LOWS: Rotation of the vane drives the governor Fig. 12-81 illustrates Fuze, B om b Nose, M 198, drum (4) directly. A governor spring (5) holds that contains a timer for both arming and firing centrifugal weights in contact with this drum; de­ processes. The parts operate as follows: Upon sign of the spring and weights provides for a release fro m the aircraft and consequent with­ governing speed of approximately 1950 rpm. drawal of arming wire, the arming pin (1) is This motion translated through a gear reduction (6) drives the arming gear (7). The arming delay is determined by the arc through which this gear I — A R M IN G PIN 8 — ARMING STEM J>— F IR IN G PIN 9 — SLIDER J — VANE 4 — GOVERNOR DRUM IO- PRIMER 5 — GOVERNOR SPRING 6 - GEAR REDUCTION II — DETENT 7 — ARMING GEAR 12— DISK A S S E M B L Y T5 1 3 — TIM IN G DISK L E V E R 14— FIRING PIN SPRING RETAINER SECTION AA END VIEW F ig u re 72-8. Fuze, B o m b N o s e , M 798 12-9

AMCP 706-210 must rotate to index a notch in it with the The mass, 6.34 x 1 0 '4 slug, is calculated from arming stem (8). The stem then moves forward volume and density; the spring constant, 6.43 and allows the slider (9) to move by spring action in.-lb, is obtained from Table 6-l; and by letting bringing the primer (10) into line with the firing S be 0.55 in., one-half the maximum travel (the pin and the rest of the explosive train. A spring same as x ), the time is found to be 4.5 msec. loaded detent (11) then drops into a hole in the This short time may be neglected. Even with a slider and holds it in the armed position. friction force of 1 lb, the time is only extended to 6 msec. For all practical purposes then, the (b) FUNCTIONING IS ACCOM PLISHED time to eject the arming pin may be neglected AS FOLLOWS: Ejection of the arming pin re­ in computing the arming delay. moves a projection on it from a slot in the Disk Assembly, T5 (12) allowing the movement to 12-4.3 THE PRO PELLER start. Starting is assured by a spring-loaded mem­ ber (not shown) which sweeps across the escape The propeller has two vanes which act like the wheel imparting motion to it. The timing disk blades of a windmill as shown on Fig. 12-8. They lever (13) rids the periphery of the disk assembly until the notch in the disk from which the arming pin was ejected indexes with the lever. The spring- loaded lever then drops into the slot releasing a system of levers which in turn releases the spring- loaded retainer firing pin spring (4). This retainer then drives the firing pin into the primer firing the fuze. The functioning delay is determined by the arc through which the Disk Assembly, T5 must rotate before the system of levers is ac­ tuated. The functioning delay may be set in 0.5 sec intervals between 4 and 91 sec. This is accom­ plished by rotating the head and bearing housing assembly relative to the body assembly. The arm­ ing delay is automatically set at about half the functioning delay. 12-4.2 THE AR M IN G PIN The arming pin must be removed before the COTTER PIN disk assembly can turn. Fig. 12-9 shows the de­ tails of the arming pin assembly. The arming pin 0.0478 is held by a cotter pin during shipment and in­ stallation in the bomb rack. The initial spring NOTE:- ALL DIMENSIONS IN INCHES load on the cotter pin can be calculated from the Figure 12-9. Arming Pin A s s e m b l y o f Fuze, M l 98 equation for a helical spring given in Table 6-1 and by using Fig. 12-9; it is found to be 3.53 lb. The shear stress on the pin is then 580 psi which is well within normal limits. Computation of time to arm is based on Eq. 6-3 without friction or on Eq. 6-6 with friction. If one assumes negligible friction, the minimum time t for the arming pin to move a distance S is then obtained (see pars. 6-2.2.2 and 6-2.2.3 for terms) t = -1, * - S (12-3) 1 .2 -1 0

AMCP 706-210 spin in the air stream at a high rate to tu rn the instance, a safety device such as an arming wire governor drum which then regulates the rotation is n eed ed for each bom b. T he u su a l p ractice is of the first shaft of the gear reduction train. to em ploy a n octopus-type device in w h ich th e The power output of the vanes depends upon arming wires from the separate bombs are con­ th e ir efficiency in a ssim ila tin g th e en erg y of nected to one pawl on the bomb rack. the air stream. If the vanes are treated like sails, a n e x p r e s s i o n f o r t h e p o w e r d e v e lo p e d Hp , 12-5.2 DEPTH BOM BS ft-lb/see, is Hp (v? v 02') sin d cosd (12-4) D ep th bom bs are dropped from airc ra ft and are expected to explode a fte r sin k in g to a ce r­ ta in d ep th . F u ze ac tio n s th e n follow th is se ­ quence: th e fuze arm s during its free fall, w ater w h ere R is th e m e a n ra d iu s of the vane, in.; A is im p a ct does n o t affect th e fuze, an d th e fuze th e area, in? ; P a is the air density, l b / f t 3; v t is the velocity behind the blade, fps; v0 is .the velocity functions by the increased w ater pressure present in fro n t of th e blade, fps; an d 0 is th e angle of at the required depth. Of the many features nec­ attac k of th e vane, deg. T his eq u atio n req u ires essary , only th e m eth o d for p rev e n tin g w a te r em p irical v alid atio n b ecau se th e velocity of th e air stream near the vane is now known. If we as­ impact from affecting the fuze will be discussed. sume a vane angle Q of 20°, th e air n ear th e vane L e t F u z e , Bomb Tail, A N M A R K 2 3 0 (Fig. 1 2 -1 0 ) m o v in g a t 42 m p h (61.6 fps), a n in c re a se in a ir serve as an example. speed ‘after passing through th e vane by 10% to This fuze is arm ed in the air before it hits the 6 7 .7 6 f p s , co 1 6 0 vrrad /sec, a n a r e a o f 0 .0 4 in ? , and a radius of 1.2 in., th e power generated will w a te r. T h e a rm in g p ro c e ss re le a s e s d e te n ts (5) be 10.5 w a tt. T h e d e n s ity o f a ir p „ is a ssu m e d t h a t fre e th e d e p th s p rin g (9). U p o n w a te r s u r ­ to be 0.08072 lb /ft3 . T hus th e pow er g e n e rate d is slightly more th a n th a t consumed by an elec­ face impact, th e firing plunger (7) tends to move tric clock. fo rw a rd in to th e firin g p in (6) b u t th e in e rtia 12-5 SPECIAL FUZES c o u n te rb a la n c e (8) r e s tr a in s it. A n a p p ro x im a te A n u m b er of special fuzes are u sed in bom bs th a t cover various tactical uses, e.g., bomb clus­ setb ack force m ay be calcu lated from E q. 5-10 ters, depth bombs, and fragmentation bombs. from th e d ra g force on th e bom b b ecau se th e 12-5.1 B O M B CLUSTERS d ra g coefficient for th e bom b in w a te r is th e Bomb clusters are used to drop several bombs same as th a t for the bomb in air5 . a t one tim e w ith one bom b sighting. U sually, W hile bomb velocity v aries w ith drop height, sev eral sm all bom bs are enclosed in a single casing. A n explosive device d isru p ts th e casin g velocity reaches a constant value eventually when an d sep arates th e bom bs before th ey strike th e g round. H ence, a fuze is n eed ed to o p era te th e th e drag force in air ju st equals the bomb weight. explosive device. Since this fuze functions fairly close to th e airc ra ft, low explosives, su ch as This steady velocity, attained during free fall, is b lack pow der or nitrocellulose, are specified w ith in itia to rs sim ilar to cartrid g e prim ers. O f also th e w a te r e n try velocity. E q. 5-3 is th e n course, each bom b h a s its ow n fuze th a t m u st not be initiated by th e cluster fuze. u sed to determ ine KD (see p a r . 5 -3 .1 .1 for term s) Wg If th e b om bs are too larg e to be enclosed in one casing, they may be packed in a bundle th at 12p d 2zv„2 (12-5) separates upon release from the aircraft. In this from w h ich th e force on th e p a rt of w eig h t is from Eq. 5-10 F = — = 775 Up (12-6) when the densities of w ater p w and air P a at 20” C are substituted in Eq. 12-6. T h e c o u n te rb a la n c e w e ig h ts (8) a re effective because th ey create a larg er m om ent th a n th e firing plunger (7) a t the pivot p in (3). Eq. 12-6 is used to calculate the forces from which the stress in th e pivot is found (see par. 6-4.2). 12-11

AMCP 706-210 Figure 12-10. Fuze, Bomb Tail, AN MARK 230 The operation of proximity fuzes requires the follow ing com ponents: radio tra n s m itte r an d re ­ W a te r se e p s th ro u g h th e w a te r p o rts (4) a n d ceiver, selective amplifier, electronic switch, elec­ (2) in to th e b ello w s (1). W h e n th e w a te r p r e s ­ su re exceeds th e p re ssu re o u tsid e th e bellow s, tric detonator, electric power supply, and safing the expansion moves the firing plunger. Bellows an d arm ing device. are m an u factu red w ith specified pressurem otion ratios. F o r bom bs, th e rad io m u s t be b u ilt so th a t it 12-5.3 FRAGMENTATION BOMBS is relatively insensitive to vibrations produced by the buffeting of the air stream. The radio signals F ragm entation bombs contain fuzes th a t m ay sh o u ld b e c o n c e n tra te d in fro n t o f th e b o m b so be initiated either after a preset time interval or th a t the ground will reflect the waves strongly. A upon targ et influence6 . T he p ro x im ity fuze il­ dipole antenna w ith a reflector has a lobe-shaped lustrates the latter initiation features. Proximity ra d ia tio n p a tte rn as sh o w n in F ig. 12-11. T he f u z e s d e t o n a t e t h e m i s s i l e u p o n i t s approach to a w ide lobe in d ic a te s th a t th e se n sitiv ity is a b o u t target (a direct hit is not required). In m any in­ the same for all angles of impact near the verti­ stances, explosion before a c tu a l co n tact is th e cal. Common angles of ground im pact for bombs conditionin which m axim um damage is inflicted. d ro p p ed fro m v a rio u s h e ig h ts v a ry fro m 55° to 72” as shown in Table 12-2. T he concept of o p eratio n of p ro x im ity fuzes is offered m erely as a n in tro d u c tio n to th e su b ­ T he p roxim ity fuze is in itia te d by circu m ­ ject of proxim ity fuzes. T hese fuzes are tre a te d in detail in other pubhcations p_t. stan ces ex p lain ed by th e D oppler p rin cip le: If th e re is relativ e m otion b etw een source an d re ­ Since p ro x im ity fuzes d eto n ate a s th e y a p ­ ceiver, the received waves will differ in frequency p ro ach th e targ et, th ey are id eal for bom bs in ­ fro m the tran sm itted waves. Fig. 12-12 shows the te n d e d to be ex p lo d ed a s a ir bursts . A ir b u rs ts condition in w hich th e receiver gets w aves re­ have advantages over ground bursts because frag­ flected from the ground just as though an image ments of an exploded bomb and dispersed chem­ source beneath the ground w ere sending them . icals travel in relatively straight lines. A ditch or Since this image is equidistant from ground level slight hill offers a high degree of protection from with the source, it moves tow ard the ground sur­ ground bursts to soldier or truck. If the bomb ex­ plodes in the air, fragm ents or chemicals will be face at the same velocity as the bomb falls. The h u rled into foxholes or over barriers so th a t the received frequency f is shielding effect is greatly reduced. The height at which an air burst produces its maximum damage fr = ft ^ , cy cle/sec (12-7) is ra th e r critical. I t m u st be h ig h en o u g h to ex ­ pose the proper targ et area b u t not so high th a t i n w h i c h Cjfys t h e v e l o c it y o f t h e r a d i o w a v e s , the target is beyond the lethal range of fragm ents f is th e frequency tran sm itte d , an d vL- v $ th e or the optimum range of chemicals. v e rtic a l velocities of receiv er a n d source. Since th e bom b velocity v s « cL , th e ex p ressio n for F rcan be approxim ated by (12-8) an d th e difference in freq u en cies becom es 2 v J J ci- The receiver compares the two signals (the re­ flected and a portion of the transm itted) by am ­ plifying the beat frequency note (2 v s f (/ c L ) p ro ­ duced by th e tw o sig n als. T he am p litu d e of th is note depends upon the am plitude of the reflected signal which is a function of target range. In this way, fuze in itiatio n is controlled by bom btarget d is ta n c e . 12-12

AMCP 706-210 w ants the fuze to be initiated at a certain height above ground regardless of bomb release altitude. T herefore, h e m u s t d esig n th e am p lifier to h av e a c o n stan t g ain th ro u g h o u t th e possible ran g e of b e a t frequencies. A response curve shaped as shown in Fig. 1213 will suffice. Figure 1 2 -1 1 . Antenna Pattern of Bomb Proximity F ig u r e 12-13. T y p i c a l A m p l i f i e r R e s p o n s e C u rv e Fuze 12-5.4 BOMBLET FUZES CL= VELOCITY OF RADIO WAVEQ t As m entioned in par. 12-5.1, bomb clusters are GROUND m ade up of sev eral bom bs or bom blets, each b o m b le t being fu z e d individually. B o m b le t fuzes V. are designed in the same m anner as bomb fuzes; // // ' IMAGE the intended apphcation dictates the fu n c tio n in g action. A n ex am p le of a bom blet is show n in F ig . 1214. I t is th e a n tita n k B om b, B L U 7/B, equipped w ith a mechanical impact fuze. Fuze action is as follows: W hen the b o m b le t is ejected from its dispenser, th e fuze safety clip (1) is w ithdrawn. The air stream tears off the retain ­ in g clip (2) th a t p e rm its th e re ta in in g s tra p (3) and a ir c h u te (parachute) protector (4) to fall off. T h is action p erm its th e ribbon airchute-folded w ith in th e p ro tecto r-to open up an d function. Functioning of th e a ir c h u te yanks out the cap (5) a p p r o x i m a t e l y lA in c h . T h e f i r i n g p in , a t t a c h e d to th e cap by a sp rin g pin, also m oves w ith th e AIRCHUTE ASSEMBLY PACKED HERE (5) CAP CONTAINING SAFETY THUMB SCREW Figure 12-12. Doppler Principle 14) PROTECTOR B om b velocity v arie s w ith drop h e ig h t as F ig u r e 12-14. B om b, BLU 7/B show n in Table 12-2, w hich m eans th a t th e fre­ q u e n c y of the received signal will vary and hence th e b e a t freq u en cy w ill v ary . B u t th e d esig n er 12-13

AMCP 706210 cap. Withdrawal of the firing pin from its posi­ nism that provides a delay of 0.8 to 1.3 sec, at tion against the side of the rotor permits the which time the stah detonator is in line with the spring-load&d rotor to turn. However, rotation firing pin. The explosive train consists of deto­ of the rotor is slow ed down by a delay mecha­ nator, lead, booster pellet, and shaped charge. REFERENCES a-t Lettered references are listed at the end of this 4. TB 9-1980-1, Fuze, Bomb: N ose, M904 Series; Fuze, Bomb: Tail M905; Fuze, Bomb:Tail, M906; handbook. Fuze, Bomb: MT, M907, M908, M909 and Delay Elements M9, T5E3, and T6E4: Descriptionand 1. TM 9-1325-200, Bombs and Bomb Components, Dept, of Army, April 1966. Use, Dept. of Army, February 1966. 2 . F u zin g Systems for Air Launched Weapons (U), G. Birkoff, Drag o f Projectiles W ithout Yaw, J o in t T e c h n ic a l C o o r d in a t in g G ro u p fo r A ir 5. U.S. Army Ballistic Research Laboratories, Re­ Launched Non-Nut lear Ordnance, JTCG-ALMNO, port 422, Aberdeen Proving Ground, Md., 30 Oc­ tober 1943. issued by the Naval Air Systems Command, I J. J. Gehrig, Lethal A r e a s o f Some Fragmenta­ I Washington, D.C., 1966 (Confidential). 6. tion W eapons, U.S. Army Ballistic Research 3. Marvin Kasper and Arthu r Wrenn, MK 81 and Laboratories, Report 717, Aberdeen Proving MK 82 Bomb Release Curves, U.S. Naval Ord­ Ground, Md., September 1953. nance Laboratory, White Oak, Md., Technical Report 65-230, 20 May 1966. 12-14

AMCP 706-210 CHAPTER 13 STATIONARY AMMUNITION FUZES 13-1 GENERAL manually, m echanically by m inelayer, or de­ livered aerially. Stationary ammunition, such as a mine, is am­ m unition that is set into place to im pede enem y Fuze, M603, a typical m ine fuze, is show n in advance. W hereas other am m unition travels to Fig. 1-5, installed in the high explosive Antitank the target, stationary ammunition demands that Mine, M15. When pressure is applied to the top, the target approach it. Its fuzes are designed with a B elleville spring is reversed and drives the firing the same considerations as those for other ammu­ pin into the detonator. nition except that environm ental forces cannot usually be used for arming action. Fuzes for sta­ Land mines are triggered mechanically by pres­ tionary ammunition contain a triggering device, sure (as Fuze, M 603), pull, or release of tension. two independent arming actions, and an explosive Pressure-operated antipersonnel mines are de output charge. Incendiary and chemical charges signed to be trig g ered by lo ad s of ab o u t 25 lb. are used occasionally. Stationary am m unition is Antitank mines are designed so that they will not often hidden from view by burying it in the initiate w hen a person walks on them. They are ground, planting it under water, or disguising it triggered by a force from 200 to 750 lb. H idden in harm less looking objects (boobytraps). Fuzes trip w ires can be used to set off the m ine w hen are initiated by mechanical or electrical stimuli pulled (tension) or cut (tension releases). through either contact or proximity action of the approaching target. Influence devices such as magnetic dipneedles or magnetometers may also be used to fire anti­ 13-2 LAND MINES tank mines in cases where it is desirable for firing to occur between the treads of the vehicle. Here, 13-2.1 LAN D MINE TYPES technology m ust be applied, involving study of the magnetic disturbances produced by moving A land mine is a charge of high explosive, in­ armor of the weight and speed it is desired to in­ cendiary m ixture, or chemical composition en­ tercept, and the heading in the earth's magnetic cased in a metallic or nonmetallic housing w ith field. an appropriate fuze, firing device, or both that is designed to be actuated unknow ingly by 13-2.2 REVERSING BELLEVILLE SPRING TRIGGER enemy personnel or vehicles. Although meant to dam age or destroy enemy vehicles and other Reversing Belleville springs provide a conven­ materiel or to kill or incapacitate enemy person­ ient m ethod for initiating land mines. W hen a nel, the primary function of a land mine is to de­ force is applied to this special type of Belleville lay and restrict the movements of the enemy' ,2. spring in one of its equilibrium positions, the spring flattens and then moves rapidly into its Land mines are divided into two general classes other equilibrium position. As indicated in Fig. d esig n ated antipersonnel a n d antitank. A nti­ 13-1, the spring does not require any external personnel m ines may be of fragm entation or force to snap through to the second position blast type. Both types m ay be designed to ex­ after passing the flat position. These springs are plode in place, whether buried or emplaced above designed w ith the equations below. In applying ground. Others, known as bounding mines, con­ the equations it is im portant that dim ensions be tain an expelling charge that projects the frag­ consistent. The spring force is given by menting component of the mine above ground be­ fore it detonates. Antitank mines are used against (13-1) tanks and other w heeled or tracked vehicles. These mines may be of the blast type or may em­ F maximum occurs when ploy the shaped charge effect. Mines are emplaced 13-1

AMCP 706-210 APPLIED FORCE (13-2) For purposes of reliable initiation, the designer may prefer to place the detonator at the position y in which the firing pin has the maximum kinetic energy. This position is found by further deriva­ tions based on the above equations3 . Suppose a reversing Belleville spring is needed for a m in e th a t is a c tu a te d by a m in im u m force o f 35 lb. A cco rd in g to th e sp ace a v a ila b le d m a y b e 2 in . a n d d i = 0 .5 in . F o r nonmagnetic an d n o nm etallic m in es a phenolic lam in ate (E = 13.5 x 10s psi, v = 0.3) is u se d for th e spring material. This leaves the spring height h a n d th e th ic k n e s s t s to b e d e te r m in e d . E q . 13-2 gives th e deflection y for m ax im u m p ressu re in te rm s of h and t,. As a trial let ts = 0.025 in. and h = 0.25 in. so th a t y becomes 0.107 in. Substi­ tu tio n of these values in Eq. 13-1 gives the m axi­ m u m sp rin g force F a s 144 lb w h ich is too g re a t for a 35 lb actuating force. F o r a second tria l, h is re d u c ed to 0.15 in. from w hich y a t th e m ax im u m load becom es 0.066 in . T h e n from E q. 13-1, th e m a x im u m force b eco m es 31 lb. T h is v a lu e falls w ith in th e specified lim it. I t re m a in s to d eterm in e w h eth e r th e sp rin g m a te ria l w ill w ith sta n d th e stresses cau sed by th is load. Eq. 13-4 in d ic ates th a t th e m axim um s t r e s s i n t h e s p r i n g <7 i s 4 9 ,0 0 0 p s i w h i c h is not excessive for a phenohc laminate. w here E is the modulus of elasticity of the m ate­ 13-2.3 PULL-RELEASE TRIGGER rial, t t is the leaf thickness, y is the spring deflec­ The pull-release device is a trigger th a t illus­ trates the use of a trip wire. One for a land mine tion, h is the initial distance of the leaf from the is sh ow n in Fig. 1 3 -2 1 . T h e m a in fuze body is c e n t e r p o i n t (s e e F ig . 1 3 - 1 ) , v is P o is s o n ’s r a t i o m o u n ted firm ly to th e m ine. T he trip w ire is for the material, d„ and d . are the outer and inner stretched across the expected path of enemy ad­ vance an d th e slack ta k e n up by tu rn in g th e d iam eters, respectively. B is th e follow ing p a ­ k n u rled knob. T he safety co tter p in is rem oved ram eter an d th e device cocked by tu rn in g th e k n u rled knob u n til th e safety p in can be rem oved from 6 (d0 - d . ) 2 its slot. T he sh o u ld e r on th e sa fe ty p in a n d th e safety wire are interlocks th a t require the device d l n in (d o/ d 0 to be arm ed in this sequence. The device is now ready to be triggered. M axim um stress a max occurs on the inner edge The pull-release device also serves to provide ° an antiremoval feature. When the mine is buried in the ground, the device is planted on the mine of the spring w hen y - h and is given by with the wire attached to the ground. Personnel / d- d, . d\\ who remove th e m ine will set th e fuze off. 1_ 2 The essential part of the trigger is an expansible 2 ( l n f y d ' - d ' ) ' (13-4) socket shown schematically in Fig. 13-3. W hen a + 2 d t (do + d t ) I 13-2

AMCP 706-210 KNURLED KNOB F ig u re J3-2. p u ll-re le a s e Device tension is applied to the trip wire, the trip plun­ faces of the fingers, the equations of equilibrium ger and the firing pin with four cantilever spring (13-6) fin g e rs m ove to th e rig h t a n d co m p re ss th e coil will be spring. If the large section of the fingers passes from b e n e a th th e sh o u ld er, only th e stiffn ess of F . Ft the fingers and the friction at the joint can retard mm= F c o s d + u F s i n d = t h e i r o p e n i n g . A s t h e s p r i n g fo rc e Fs in c r e a s e s , the forces at point B increase causing the fingers 4\" 4 to deflect an d th e jo in t to se p a ra te . T he trip p lu n g e r co n tin u es to th e rig h t, an d th e firin g F,I - nF s in d - 'uFn c o s $ p in is d riv en into th e d eto n ato r by th e firing pin spring. T h e tw o e q u a tio n s are solved sim u ltan eo u sly w ith E q. 13-5 to yield th e trip w ire trig g e rin g The forces on the trip plunger and finger are fo rc e Ft ( p e r p e n d i c u l a r to t h e w ir e ) in d ic a te d on F ig. 13-3. T he force Fj (ac tin g as th e reactio n to a co n cen trated load on a ca n ti­ Section A -A -FRICTION lever beam) is given by Enlargement o f Poi n t B FORCE w h ere y is th e deflection a t B , [ is th e effective TRIP length of the finger, E is the modulus of elasticity, PLUNGER an d I, is th e second m o m en t of a re a a t th e sec­ Figure 73-3. Expansible Socket of Pull-release tio n AA . A ny co n sisten t set of dim ensions m ay Device be used. 13-3 I f Fn i s t h e c o m p o n e n t o f Fj n o r m a l to t h e

AMCP 706-210 ten-foot w ire, l = 120 in., S ( = 60 in., Ss = 0.3 in., a n d F = 8.7 lb; th en Ft = 1.2 lb. w h ere p. is the coefficient of friction a n d y is 13-3 SEA MINES the deflection necessary for the parts to separate. Sea mines are explosive devices placed in the The following design criteria are evident: path of vessels to impede their progress. The in­ (1) for a sensitive trip w ire, the req u ired trip herent strength of a ship requires that sea mines force sh o u ld n o t be great, hence (2) the fingers contain large explosive charges usually HBX or should not be too stiff yet should return to the TNT. They are actuated when touched or closely closed position quickly so as not to engage the approached by a ship. Since concealment in water shoulder on the firing stroke. is relatively easy, size is not necessarily lim ited so that generally there is abundant space for the To design a device similar to that in Fig. 13-2, fuze mechanisms. the designer m ight start w ith steel fingers one inch long. The cross section of the fingers m ust All naval underwater mines fall within one or be a quadrant of a ring so that its second moment the other of two broad classes, independent or of area is controlled. Once planted and armed, independent mines are actuated automatically by the presence: w here f j and r 2 are the inner and outer radii, of a ship. In contrast, controlled mines transm it respectively. If r j = 0.036 in. an d r 2 = 0.10 in., an electrical signal to a shore station when a ship I, = 2.0 x 10’6 in? The rad ia l interference be­ passes. Personnel at the shore station may either tw een fingers an d trip plunger can be 0.005 in. m erely observe the signal or m ay detonate the From Eq. 13-7 w ith 0 = 30°, the pull force on m ine by a return signal. This broad system of the trip w ire m ust be 8 lb to release the firing classifying mines is cut across by three other pin. classification m ethods, nam ely: (1) m eth o d of planting (by minelayer, subm arine, or aircraft), W hen the trip w ire is set and the device is (2) p o sition after p lan tin g (bottom , m oored, or cocked, the firing pin spring is com pressed two drifting), a n d (3) by ty p e of firin g m e c h a n ism 4 . inches. In this condition the fingers will not be The firing mechanism can be activated by con­ forced apart ( F t = 7.6 lb) and the body shoulder tact (electrochemical, galvanic, or mechanical w ill continue to restrict their cantilever action. action) or by influence (magnetic, acoustic, or Only after the spring has been compressed an­ pressure action). other 0.30 in. can the increased section pass the body shoulder. Since the spring force now ex­ Safety is provided in a num ber of ways. Sur­ ceeds the S-lb release requirement, the fingers can face laid mines usually have a soluble washer that open to release the firing pin. prevents arm ing until the washer has been dis­ solved by sea w ater (see par. 8-3). A ircraft laid To determine the sensitivity of the device to a mines employ an arm ing w ire just like bombs. tripping force Ft the following equation may be Submarine mines have a positive lock safety bar used which falls free w hen the mine is ejected from a torpedo tube. D etonator safety is provided by w here F is the spring force at release, S s is the separating the detonator from the booster. A distance the spring must be compressed from the hydrostatic extender mechanism is a common de cocked positio n to release the firing pin, 1is the vice for m oving the detonator close to the trip w ire length, and St is the distance from the booster charge. M any mines also have a tim ing fuze to the trip force. This is illustrated on Fig. m echanism to delay arm ing for a preset time 13-4. after planting. This same tim er can also serve as If the tripping force occurs at the center of a 13-4

AMCP 705-210 a self-destruction mechanism to destroy’ the mine after a fixed elapse of time. 134 BOOBYTRAPS Boobytraps are explosive charges fitted with a Fi gore 73-5. Pressure-release’ Firing Device, M5 detonator and a firing device, all usually con­ cealed and set to explode when an unsuspecting provides static friction on the shaft. When a person triggers its firing mechanism as by step­ force is exerted on the pull wire, the spring de ping upon, lifting, or moving harmless looking fleets until the force is large enough to overcome o b je c ts 5 . The pressure-release type firing device shaft friction. At this time the shaft slips through (mousetrap) is an example. Fig. 1 3 -5 5 illustrates the explosive and wipes against the igniter mix. the action of the M5 Firing Device. The release The friction generates enough heat to start the plate has a long lever so that a light weight will chemicals reacting in order to ignite the charge. restrain it. The spring propels the firing pin Design of this mechanism, therefore, depends against the primer when the release plate lifts. critically upon the force required to overcome The firing pin spring turns the firing pin through shaft friction. The spring should store enough an angle of about 180”. energy to extract the shaft, once motion is started, because the rise in temperature at the The explosive train in the fuze consists simply interface of head and explosive is a function of of the firing pin and a percussion primer. A tube shaft velocity. directs the flash to the base cup which is coupled at the threads. No delay is used. Safety is pro­ FRICTION COMPOSITION vided by a safety pin inserted and held by a cotter pin so as to prevent the release plate from lifting. Figure 13-6. Firing D e v ic e , M2 The firing pin spring is of the torsion type in which a wire coil is wound as the device is cocked. This spring force is calculated from the equation F (13-10) where l is the length of the spring, r is the lever arm of the force F, and 6 is the angle of twist in rad for the coil. For this spring the approximate dimen­ sions might be l = 0.50 in., r = 0.50 in., dv = 77 d ^ 0 .0 3 5 in ., so t h a t 1. = - f - = 0.073 x 1 0 '6 in f , 64 E = 30 x 1 0 6 psi, and 0 = n rad. F then is 28 lb, and, because of the 7 :1 lever ratio, the force on the release plate will be about 4 lb. Thus, a heavy book could serve as the bait for this boobytrap. A different method of initiating boobytraps is employed in the M2 Firing Device, shown in Fig. 1 3 -6 5. A friction device initiates a fuze from the heat created by an action similar to that of a safety match being pulled through a pair of striker covers placed face to face. The head of the wire, coated with a friction composition, usually a red phosphorus compound, is supported in a channel by a silicone compound. The igniter compound may be a mixture of potassium chlo­ rate, charcoal, and dextrine. In addition to serving as a seal, the silicone 13-5

AMCP 708210 REFERENCES 1. TM 9 - 1 3 4 5 - 2 0 0 , Land M ines, Dept, of Army, 4. NAVPERS 10797-A, Naval Ordnance and Gun­ nery- Vol. 1 , Bureau of Naval Personnel, W a s h ­ June 1964. ington, D.C., 1957. 2. AMCP 706-241 (S), E n gin eerin g Design H a n d ­ 5 . FM 5-3 1, B o o b y tr a p s , Dept, of Army, S e p te m ­ book, Land Mines (U). 3. A. M. W a h l, M e c h a n i c a l S p rin g s, M c G ra w -H ill ber 1965. Book Co., Inc., N.Y., 1963, pp. 155-175. ( 1 3 -6

AMCP 706-210 CHAPTER 14 DESIGN GUIDANCE 14-1 NEED FOR DESIGN DETAILS are due to oversight. Fuze designers are apt to consider components as complete items with Because military fuzes are subjected to greater little attention given to their materials of con­ rigors than switches, timers, or other commercial struction until a failure or high contact resistance devices, their design requires unusual care and at­ occurs that could possibly be the result of the te n tio n to detailed features. Fuzes must function outgassing of organic plastic materials. Erratic reliably, operate over a wide range of environ­ contact behavior can be minimized by monitor­ ments, and perform without maintenance after long storage. No commercial system, be it elec­ ing the choice of materials and by cleaning. trical or mechanical, is called upon to fulfill all No contact material is adequate for all switch­ of these stringent conditions. Once the fuze has been manufactured, it is stored until used. It ing situations and compromises must always be must then perform as intended. For this reason, made keeping in mind the most critical charac­ the fuze designer must make certain that all de­ teristics to be satisfied. The contact material tails are given their proper attention during de should have the following ideal characteristics: sign and development. (1) Conductivity of copper or silver Guidance is provided in this Chapter for sev­ (2) Heat resistance of tungsten eral details. This information complements the (3) Freedom from oxidation of platinum or considerations in fuze design (Chapter 9) con­ palladium cerned with having the fuze function as intended (4) Resistance to organic film formation of as well as the general design considerations gold (Chapter 2) treating such factors as design philos­ (5) Inexpensiveness of iron. ophy, economics, standardization, and human There are two distinct types of contact con­ factors engineering. Some of the details presented tamination, organic or thin film contamination here pertain to common components such as and particle or particulate contamination’ . The switch contacts or time setters. Others treat the effect of particle contamination can be highly use of materials and lubricants, the selection of disastrous because of its erratic behavior. Monitor which can adversely affect fuze performance. tests can show low resistance for hundreds of Subjects like tolerancing, potting, and packaging operations with a sudden rise to a very high re ­ deal with assembly problems. sista n c e value. Since not all particles can be burnt away by the contact current and voltages, it is 14-2 PREVENTION OF CONTACT CONTAMI­ evident that particulate contamination can per­ NATION sist for a very long time. Organic film contami­ nation, on the other hand, will generally indicate The widespread use of transistor circuits in a gradual rise in the contact resistance and can be fuzes for electromechanical devices such as re­ partially burnt away if the voltages are high lays and switches has emphasized the problem of contact failure in low-level switching circuits. enough. Since transistor circuits are characterized by low Particle contam ination can be caused by: voltages and currents, care must be exercised in (1) Poor choice of insulating material the selection of the contacts employed. A high (2) Poor cleaning of machined and finished percent of relay failures can be charged directly to contact failure. One of the most prevalent fac­ parts tors that causes contact failures is contamination (3) Use of poor grades of internal gas which results in excess contact resistance and (4) Normal wear or erosion particles. wear. Organic film contamination can be caused by: (1) Poor choice of insulating materials Many switch contact contamination problems (2) Inferior cleaning techniques (3) No bake-out of organic parts (4) Poor choice of soldering techniques (5) Poor hermetic sealing 14-1

AMCP 706-210 (6) Lubricating oils Figure J4-I. Packing Box and Fuze Supports (7) Organic dyes present in anodized protec­ tive coatings. 14-4 LINKAGE OF SETTER COMPONENTS When contamination-particle or organic film— occurs, the following steps should be taken: Designs of mechanical setter d ev ices should (1) Determine if the contact requirements include consideration of the linkage of the setter are realistic. components and setter display components in (2) Determine if wiping action and contact conjunction with the device being set. pressures can be increased without adversely af­ fecting the operation of the device. The parallel mechanical linkage (Fig. 142(A)) (3) Make an initial, simple chemical analysis permits concurrent positioning of setter display test of contaminant. components and the item to be set. This type of (4) Determine if the contamination problem linkage could cause the display of a false reading is of a particle nature, organic film nature, or because the setter display does not necessarily both. Some of the methods for analysis are have to agree with the information actually set solubility tests, spectrographic analysis, chem­ into item (the linkage to either the setter display ical spot tests, microscopy, electron microscopy, components or item being set could be faulty). electron diffraction, X-ray diffraction, radio­ The series linkage (Fig. 14-2(B)) is little improve­ active tracers, infrared spectroscopy, and plastic ment over the first because the linkage to the replica2 . item to be set could be deficient even though a (5) Take appropriate steps to eliminate the setting is displayed. Deficiencies are more prone contamination by a complete materials review of to occur in the high-torque gear trams of the item metals, insulators, and gases used, an inspection to be set rather than in the low-torque gear trains of the manufacturer’s quality control and clean­ of the setter display assembly (the linkage be­ ing techniques, and an inspection of the validity tween the two could shear). The most reliable of test results for the hermetic seals. and safest linkage (at no increased costs) is a different series linkage (Fig. 14-2(C)) in which 14-3 PACKAGING the setting actually positioned into item being set is displayed after the fact of actual setting. Safety in transportation and storage depends to a large degree on how the fuze is packaged. Al­ though specifications and packaging designs have been standardized, the designer should be fa­ miliar with the various levels o f shipment as they might affect his design. A packaging handbook should be consulted3. For the most part, the packaging of fuzes has been standardized4. For overseas shipment (Level A), 8 artillery or 10 rocket fuzes are packaged in a water-vapor-proof, rectangular, quick-opening type, metal box having polystyrene supports to contain the fuzes (Fig. 14-1). Two metal boxes are overpacked with a wooden wirebound box. For long term storage (Level B), 36 metal boxes of packaged fuzes are placed in a pallet type box. For interplant shipment (Level C), the assembled or partially assembled fuzes are packaged in a fiberboard carton utilizing the same polystyrene supports used in the metal boxes. The rocket fuzes are placed in a carton having an eg g crate type separator. The cartons are over-packed with an inexpensive wooden wirebound box. 14-2

AMCP 706-210 co m p o u n d , a n d (7) p o ttin g co m p o u n d s m a y a f­ fect the electrical characteristics of a circuit. The m ost com m on types of pottin g com ­ pounds in use are: epoxies, polyurethanes, poly­ SETTER SETTER DISPLAY ITEM esters, a n d silicones. T ypical c h a ra c te ristic s of COMPONENTS BEING SET (HIGH TORQUE) these potting m aterials are shown in Table 14-15. ( B ) INPUT COMPONENTS \"+ Som e p o ttin g fo rm u latio n s m ay be incom ­ (LOW TORQUE) patible w ith explosives. If th e p o ttin g resin and explosive are n o t in close proxim ity, in c o m p ati­ ( C ) INPUT SETTER ITEM SETTER DISPLAY bility is of little concern. C u rin g of som e resin s COMPONENTS BEING SET COMPONENTS (HIGH TORQUE ) (LOWTORPUE] directly in co n tact w ith explosives is th e m o st ris k y co n d itio n . A lso, in tim a te m ix tu re s o f p re figure 14-2. Linkage of Setter Components cured resins with certain explosives may be dan­ gerous. It is the amine curing agent and not the resin itself th a t is incom patible w ith a n explo­ 14-5 M A TER IA LS sive. F re q u e n tly , acid a n h y d rid e c u rin g a g e n ts The characteristics and properties of the engi­ can be used n ear explosives if tem peratures are n eerin g m aterials used in th e construction of fuzes are b est d eterm in ed by consulting h a n d ­ n o t too h ig h . In a n y ev en t, th e fuze d e sig n er books and specification sheets provided by m anu­ factu rers. T he m a teria ls are continuously su b ­ sh o u ld alw ay s specify th a t m a te ria ls u sed n e a r ject to im p ro v em en ts b ecau se of d ev elo p m en t work, and technical data are subject to constant explosives m ust be compatible w ith them6. revision. This paragraph, therefore, presents in ­ formation only on a few special m aterials of p ar­ T he p o ttin g com pound d esired for a fuze ticular interest to the fuze designer. assembly should : 14-5.1 POTTING CO M PO UNDS (1) H e rm e tic a lly se a l th e u n it fro m its e n ­ P o ttin g com pounds are u sed to en c ap su late electronic p a rts for p ro tectio n a g a in st te m p e ra ­ v iro n m en t w ith a m inim um of stress a t the ture, pressure, moisture, dirt, corrosion, fungus, v ib ratio n , shock, an d arcing b etw een com po­ boundaries and a minimum of strain in the resin nents. itself. The electronic components of m oderate power rating, such as those used in fuzes, are more re­ (2) S u p p o rt th e u n it a n d c u s h io n it fro m liable an d have longer life w hen properly encap­ sulated. In this case the potting material provides shock. This requires some resiliency at all oper­ n o t only p ro tectio n from th e ad v erse e n v iro n ­ m ents but also structural rigidity. ating temperatures. D isad v an tag es of p o ttin g electronic com po­ (3) P ro v id e good e le c tric a l in s u la tio n a t a ll nents are: (1) replacing w ires an d com ponents of a potted assembly is almost impossible, (2) com­ freq u en cies, a n d low ab so rp tio n esp ecially a t pounds generally do not w ithstand very high or very low tem perature, (3) since th e potting m a­ high frequencies. te ria l occupies all free space in a n assem b ly , it so m e tim e s a d d s w e ig h t to th e a sse m b ly , (4) th e (4) P ro te c t th e u n it fro m e x tre m e te m p e r a ­ circuit m ust be specifically designed for potting, (5) extra tim e an d labor are required to clean the tu re changes, y et d issip ate th e in te rn a l h e a t circu it a n d to p ro tec t co m p o n en ts p rio r to e m ­ bedm ent, (6) component h ea t is trap p ed an d re ­ generated. . tained by the insulating character of the potting (5) B e t r a n s p a r e n t so t h a t e m b e d d e d com­ ponents can be seen. (6) Have good adhesion to all potted surfaces including sides of the container. (7) Have a curing or baking tem perature not h ig h e r t h a n 150°F . H av e low i n t e r n a l tempera­ tures due to controlled, slow exotherm al reaction. (8) Not shrink during curing. (9) N o t b eco m e b r ittle a t te m p e r a tu re s a s low as -65” F, m elt a t high tem peratures, or lose an y of th e above d esirable q u alities a t any op­ erating tem perature. (10) R e sist d e te rio ra tio n by th e w e a th e r an d chemical agents. (11) B e co m p atib le w ith th e e m b ed d e d com ­ ponents and adjacent materials. (12) N o t ca u se o rg an ic or p a rtic le c o n ta m i­ nation of electrical contacts (see par. 142). 14-3

AMCP 706-210 T A B LE 14-I. CO M PARISO N OF PROPERTIES OF T Y P IC A L POTTING M ATERIALS Mate Linear Therm ! Therm l Vo 1 ume Dielectric Shrinkage Expansion Conductivity Strength Epoxy Res is t iv ity Unfilled very low -m ed. low-high low -m edium good-excel. very good Filled (rig id ) very low -low low high very good-excel. very good-excel. Filled (flexible) low -high low-high m edium good-very good very good very low -low very low very low -low very good good Syntatic very low low-high very low very good (not avail.) P o ly u re th a n e very low -high high very low good-very good good-very good Foam cast m e d .-v e ry high low -high m edium good-very good very good m edium good-very good P o ly e ste r m ed .-v ery h ig h h lg h good Filled (rigid) Filled (flexible) low high very high excellent good high m edium very good very good S ilic o n e very low very high m edium excellent excellent cast (fiied) R TV rubber very high Gel K ey to R anges L IN E A R S H R IN K A G E , (in./in.): v ery lo w 0.0 02 ; lo w 0 .0 0 2 1 -0 .0 0 4 ; m e d iu m 0 .0 0 4 1 ­ 0.010; h ig h 0.0101-0.010; very h ig h 0.0201. T H E R M A L E X P A N S IO N , (in./in.°C)x 10'5: v ery lo w 2 .0 ; lo w 2 .1 -5 .0 ; h ig h 5 .1 -1 0 ; very h ig h 10.1 (fig ures referen ced against alum inum ). T H E R M A L C O N D U C T I V I T Y , (cal/sec/cm2 /°C p e r c m ) x 10'4 : v e r y lo w 1 .5 ; lo w 1.6— 4.0; m edium 4.1-9.0; hig h 9.1-20; very h ig h 20.1. V O L U M E R E S IS H V IT Y , (ohm -cm ): good 10’ 1-1 0 ’ J ; very good 10’ 1 -1 0 ’ 4 ; excellent 10’ s -10’ 7 . D I E L E C T R I C S T R E N G T H , (volt/m il): g o o d 2 2 5 -3 9 9 ; v e ry g o o d 400—500; e x c e lle n t 5 00 . 14-5.2 SEALIN G MATERIALS rubber, synthetic rubber, and plastics. Whenever possible, the designer should use this kind of me­ In addition to the potting compounds, the se­ chanical seal rather than liquid or paste because lection of sealing methods for fuzes requires the production quality is more readily assured. careful consideration of the designer. The locations and uses of seals in a typical elec­ A sealant is a liquid or paste which is applied tronic fuze are shown in Fig. 14-3. to a joint to prevent or reduce the penetration of gases, liquids, dust or all of these. Two types The following factors must be carefully of joints on which sealants are often used in fuze weighed when selecting a sealant or sealing construction are the butt or crimped joint, and material: the threaded joint. A sealant used on threads must not act as a cement for the threaded joint, (1) Physical properties of the sealant or but must be easily broken to permit inspection sealing material, such as tensile strength, com­ or repair of enclosed components. A sealant for pression set, elongation, and hardness. a butt or crimped joint has greater latitude be­ cause this type of joint is usually a permanent (2) Chemical compatibility. The seal must be one and cementing is desired. chemically compatible with the metals, fuels, lubricants, explosives, acids, or other materials The term sealing materials is also one which to which it may be exposed (see also item (4) refers to the sheet stock and molded shapes of below). resilient character which form the gasket type of seal commonly used in fuzes. The materials (3) Storage characteristics. The seal must most often used for this purpose include natural withstand exposure to a wide range of environ­ ments over a long period of time in storage. 14-4 (4) Outgassing. Any products of outgassing, especially during the curing process of the sealing

AMCP 706-210 material, must not cause particle or organic con­ electric and proxim ity fuzes, have a num ber of tam in atio n of electrical contacts (see par. 14-2) desirable properties. Some of these are: nor fouling or corrosion of other fuze parts. (1) They can be u se d to join m etals at rela­ (5) T em perature. tively low temperatures. No sealant or sealing material has all the quali­ ties required. The problem, then, is to choose the (2) They can w ith sta n d considerable b e n d ­ best com bination of characteristics. Choice is ing w ithout fracture. usually based prim arily on the overall physical and chemical properties of the m aterials and (3) They can usually be applied by sim ple secondarily on its aging properties. Other things means and can be used with metals having rela­ to be considered before a final decision is m ade tively low melting points. are availability of materials, cost, ease of applica­ tion, toxicity, useful pot life, and service life'. The most commonly used soft solders are tin- The materials commonly used as sealants in­ lead alloys. These soft solders have the prim ary clude various rubbers, neoprene, polyesters, disadvantage that they have low strength com­ alkyds, phenolics, vinyls, and flexible epoxy pared with the metals usually joined. Character­ resinss . No sealant has been fo u n d w hich w ill istics of soft solder alloys are show n in Table produce a joint as tight as a w ell-soldered joint. 14-2. The designer should look to the present ef­ fort m ade to apply one-com ponent sealers so as Conductive adhesives can sometimes be used to avoid pot life problems. in applications where heat generated during the soldering process m ight damage tem perature- POLYETHYLENE sensitive components. Typical applications in­ clude bonding barium tita n a te elements together NOSE CUP or to ferrite rods, m aking electrical connections to battery term inals, and repairing printed cir­ cuits. 14-6 CONSTRUCTION TECHNIQUES Two important aspects must be considered in the design of a fuze. First, the components must be selected and incorporated into the fuze in such a m anner that they will perform their in­ tended function properly. Second, the com­ ponents m ust be assembled into the completed fuze so as to m aintain their in teg rity , their re­ lationship w ith one another, and their function­ ing reliability in spite of the extreme environ­ m ent to which they are subjected. This second aspect requires unusual care in the construction and assembly of the fuzes in order to assure proper performance. ■* TYPE D -C -33 14-6.1 M ECH ANICAL CONSIDERATIONS N O T E : \"0“ R IN G S COATED W IT H D O W -C O R N IN G The permissible volume and weight of the fuze and its location are generally specified at the S ILIC O N E G R E A S E O R EO UAL start of a program. The anticipated fuze environ­ ments during operational use and during storage, Figure 14-3. Location of Seals in a Typical handling, and transportation are also specified. Electronic Foze These environments, particularly any unusual ones, m ust be kept in m ind from the start of a 14-5.3 SOLDERS fuze program. Solders are one of the m ore troublesom e en­ When designing housings, packages, and other gineering materials9 0 . The two general classes m echanical parts of a fuze, it is not sufficient to of solder are soft solder and hard solder. consider only the mechanical requirem ents for Soft solders, which are used extensively in 14-5

AMCP 706-210 T A B L E 1 4 -2 . L O W -M E L T IN G S O F T S O L D E R S U S E D IN E L E C T R IC A L E Q U IP M E N T Sn, % Pb, % B i, % Cd, % Liquidus ,°F S o lid u s, °F Use 18 30 70 361 4 9 6 Wiping solders 35 65 361 477 40 60’ 361 460 General purpose, 45 55 361 441 radio, TV 50 50 361 421 60 40 361 370 E lectronics, p rin ted 62 38 361 eutectic 361 c irc u its 16 32 52 205 eutectic 205 Low tem p eratu re 25 25 50 266 205 37.5 50 12.5 374 205 50 25 25 338 205 51 31 288 eutectic 288 Low tem p eratu re strength, volume, and weight. In m any instances, (7) Design all fuzes, with the possible excep­ their effect on the performance of the fuze m ust tio n of th e m o st in ex p en siv e d esig n s, so th a t be considered. T he dim ensions of som e p arts, they m ay be tak en ap a rt should a functional or and the tolerances on the dimensions, may have safety failure occur in subsequent lot acceptance a direct relation to performance. On other parts, testing. th e degree of stiffness or positio n al v ariatio n u n d e r conditions of shock or v ib ratio n m ay af- (8) L o cate o r o rie n t fu n c tio n a l co m p o n e n ts so a s to ex p erien ce th e le a s t d e trim e n ta l effect fe e t th e p e rfo rm a n c e o f a fuze. from interior and exterior ballistic environments. M any mechanical design problems can be elim­ (a) Orient gear and pinion assembly in inated by following a logical design approach. A tim ers if possible so th a t the pinion shoulder sup­ suggested approach is as follows: ports the gear under setback loading rather th an . (1) D eterm in e th e m echanical req u irem en ts relying on the staking or spin operations used in in shape, dimension, rigidity, material, and finish assembling the gear to the pinion to accomplish imposed by the functions of the fuze. th e required stru ctu ra l in teg rity under setback. (2) D e te rm in e th e m e c h a n ic a l re q u ire m e n ts (b) U se a v e rtic a l h a irs p rin g in th e in shape, dim ension, stren g th , m aterial, an d P opovitch escap em en t to reduce h a irsp rin g d is­ fin ish , etc., im p o sed by o p e ra tio n a l use, tr a n s ­ tortion due to ballistic environments thereby in­ portation, handling, and storage. creasing tim er accuracy. (3) M a k e a p re lim in a ry d e sig n a n d ch eck (9) P re p a re th e m a n u fa c tu rin g in fo rm a tio n , critical elements for stress, resonant frequency, incorporating all of th e inform ation w hich m ust static and dynamic balance, etc. be observed in th e m anufacture and inspection of the fuze. (4) E x a m in e th e s e d e sig n s w ith re sp e c t to ability of the shop to manufacture and to main­ 14-6.2 EN C A PSU L A T IO N ta in th e required tolerances (see par. 14-8). O ne o f th e m o st com m only u sed m eth o d s of (5) C h eck th e p re lim in a ry d e sig n s b y o b ­ m aintaining the functional relationship of com­ serv in g th e perfo rm an ce of a p re lim in a ry fuze ponents and preserving the integrity of the fuze m odel subjected to te s ts p e rtin e n t to th e v erifi­ is th a t of encapsulation of the m ain fuze assem ­ cation of th e design. bly. The m aterials used for encapsulation are de­ scribed in p ar. 14-5. T he p re se n t d iscu ssio n is (6) R ev ise th e d e sig n a s in d ic a te d b y th e m odel te sts and rep eat th e te sts if necessary. 14-6

AMCP 706-210 concerned with encapsulation as a construction nose of the fuze. The remaining electronic com­ technique. ponents, consisting of a two-stage amplifier and a thyratron firing circuit, are mounted immediately The basic encapsulating methods are potting, below the oscillator tube. A plastic catacomb, dipping, coating, and casting. Potting involves which houses many of the electronic compo­ melting the embedding compound and pouring it nents, is shown in the lower right part of Fig. into a pot or mold. The pot is normally left in 14-4. The catacomb also serves as a mounting place and the resin used is comparatively soft. block around which the components are wired Dipping and coating are generally confined to (Fig. 14-5). In other applications, printed end single components such as coils, resistors, or ca­ plates have been used on one or both sides of the pacitors. Casting usually involves the use of resins catacomb (Fig. 14-6). which require the chemical process of polymeri­ zation to set. The resulting compound is hard and The catacomb may be molded from a plastic the mold is stripped from it. Molds may be made material, cast, die-cast, or machined from metal. of metals or rigid plastics. Sometimes the catacombs are also molded and fired from a ceramic material. Two different approaches are possible in the embedment of electronic assemblies. One is to Fuzes for missiles often use the central spine embed the entire circuit in one large casting. The support concept. In this type of construction, a disadvantage of this is, if one component fails, structural shape, usually an I or cruciform sec­ the entire circuit is useless and must be discarded. tion, is used as the central frame of the fuze. The The repair of embedded circuits is difficult be­ components of the fuzing system are attached to cause dissolving the resin is time-consuming and this frame, then joined by interconnecting cab may be injurious to elements of the circuit. ling, with the covering skin forming a second Drilling and other machining processes to gain portion of the structure surrounding the fuze. access to defective components are expensive, time-consuming, and practical only where clear 14-7 LUBRICATION resins have been used. A lubricant is expected to perform the jobs of The second approach is to make several smaller minimizing friction, wear, and galling between castings, embedding components such as tubes sliding or rolling parts. It must do these jobs (having high failure rates) separately. This re­ under two types of conditions: (1) those which duces the possibility of having to throw away are inherent in the component element itse lf- large castings containing many usable compo­ such as load, speed, geometry, and frictional nents when one component fails. Ideally, unit heat-and (2) those which are imposed from ex­ casting should contain components having simi­ ternal sourcessuch as temperature and compo­ lar life expectancies. sition of the surrounding atmosphere, nuclear radiation, inactive storage, vibration, and mech­ 14-6.3 SUPPORTING STRUCTURE anical shock. The imposed conditions are usually the more restrictive ones for lubricant selection. Because of the extreme environments of shock and vibration in which fuzes must operate, a Mechanical fuze components contain elements great deal of design effort is devoted to the main which undergo a variety of sliding and rolling structure of the fuze. There are two common motions, and combinations of the two. For ex­ concepts used in the construction of the main ample, a mass translating on guide rods involves fuze structure-the catacomb concept, and the linear sliding only, the balls in a ball bearing in­ central spine support concept. volve essentially all rolling motion, and meshing gear teeth surfaces experience both rolling and Fuzes for conventional weapons, such as sliding motions. For any given type of motion, rockets and mortar projectiles, are generally of the lubricant found to be satisfactory in one case catacomb construction. Ideally, all parts should will not necessarily be suitable for another if be made as a block so that the completed fuze is loads, speeds, etc., are not similar. literally “as solid as a rock.” Selection of the proper lubricant requires not Fig. 14-4 shows the basic construction of a only knowledge of the specific function which typical mortar proximity fuze. The top part, the lubricant is required to perform in the de­ which is made of plastic, contains a four-tube vice being lubricated but also consideration of electronic system with the RF oscillator in the J4-7

AMCP 706-210 PRINTED C IR C U IT ASSEMBLED ELECTRONIC AMPLIFIER HEAD OSCILLATOR A M P L IF IE R ASSEMBLY Figure 14-4. Construction o f Typical M ortar F u re , M517 Figure 14-5. Catacomb Amplifier Figure 14-6. Catacomb Am plifier W ith Printed End Plates HP

AMCP 706-210 the interactions include chemical processes— greases, and solid-with summaries of their pro­ such as corrosion of the metal parts by compo­ perties are contained in a JANAF Journal nents of the lubricant, e.g., corrosion due to Article’ 1 . oxidation of M oS2 in the absence of suitable in­ hibitors, or solution of copper alloys during lub­ 14-8 TOLERANCING ricant oxidation processes; or physical interac­ All fuze parts must be properly to le ra n c e d tions, e.g., attack by active organic materials on following good design practice. Every length, synthetic elastomers and plastic structural mem­ diameter, angle, and location dimension must be bers. In addition, the inherent stability of the given and defined in tolerances as broad as the lubricant must be considered. Stability is of par­ performance of the part can tolerate to permit ticular importance if storage for long periods of most economical manufacturing procedure. Par­ time with or without elevated tem peratures ticularly in high-volume parts, costs rise rapidly (which speeds up oxidation rate) is involved. (In as tolerances are made tighter. All fits must be general, lubricants are inhibited against oxidation stipulated. These fits should be chosen with pri­ by appropriate additives, but since temperature mary consideration for function and accuracy, is an important parameter, the oxidation sta­ but they should be usable in inspection and bility characteristics of the lubricant should be manufacturing. All tolerance combinations and taken into account in connection with the ex­ permutations must be both workable and safe. pected storage life and pertinent temperatures of the mechanism being lubricated). Oxidation Assembly drawings can readily show the phy­ of fluid or semi-fluid lubricants may lead to sical relationship of various components but thickening of the lubricant with consequent in­ interferences and clearances must be calculated from the dimensions1 1 Tolerance stack-ups in­ creased forces being required for operation, or dicate whether parts can be properly assembled corrosive attack on the materials of construction. and whether an assembly will operate as ex­ pected. Consideration should be given to ex­ A wide variety of fluid and semi-fluid lubri­ p e c te d user environments, temperature extremes, cants are available covering a wide temperature and their effects upon critical interference and range of applicability, a range of compatibility clearance fits. with organic and inorganic structural materials, and a range of other properties which may be It is imperative in the development of mech­ pertinent, e.g., nonspreading, lubricity, etc. In anical timers and fuzing that tolerance stack-up addition, both dry powdered and bonded solid- determinations be complete before the manu­ film lubricants are available. The choice of a lub­ facture of development hardware. It is further ricant depends on the totality of functions which imperative that all engineering change orders the lubricant must perform, and the structural (development and production) request continual and functional features of the mechanism being review, revision, and updating of original stack-up lubricated. For example, a very severe n o n s p re a d ­ calculations with every contemplated change. ing and low vapor pressure requirement in con­ This is extremely important because tolerances in nection with long term storage may lead to a mechanical timer and fuzing systems are on order choice of a solid lubricant; whereas adhesion of 0.001 inch. Value engineers must be particu­ problems with bonded lubricants at high loads or larly alert to this requirement. Even extremely with thin films associated with low mechanical small undesired interferences and/or clearances tolerances may complicate the use of dry film can cause: (1) expensive failures, those that are lubricants. In fuzes subject to high rates of spin difficult to debug, (2) delay in meeting sched­ (above 25,000 rpm), fluid and semi-fluid lubri­ ules, (3) cancellation of ideas that are worthy of cants tend to be displaced by centrifugal force continued effort, (4) failures of an inconsistent causing loss of lubricant and possible contami­ nature, (5) inability to apply corrective measures, nation of other fuze parts. Requirements for and (6) uncontrollable quality assurance pro­ corrosion protection may require additives not grams. accessible with dry lubricants. The true-position dimensioning system (de­ In simpler fuzes, choice of proper materials, fined in MIL-STD-8B) is a method of expressing plating, and finishes can obviate a separate accurately the location and size of critical fea­ tures of mating parts. True-position dimensioning lubricant. Descriptions of available lubricants--oils, 14-9

AMCP 706-210 consists of establishing exact locations of impor­ to the difficulty in the selection of components. tant features, identifying these locations as exact For these reasons, the designer should use or basic, and using the true position symbol, with a tolerance, to control the variation of the future. standard components whenever possible (see The system should be applied where close control par. 2-4); he must be well acquainted with the or precise interpretation of locations is needed. environmental conditions under which the fuze It involves calculating tolerance limits early in operates (see par. 9-2.1); he must also recognize the design stage. This, in turn, encourages the use the effect of the combination of different con­ of realistic and practical dimensions to satisfy ditions. O f particular importance is the relation­ design intent. ship between temperature and rate of chemical action. This relationship is a critical factor af­ Tolerancing affects the interchangeability of fecting the storage life of equipment. Explosive components. Complete interchangeability of components present special problems to the fuze components is desirable whenever feasible. How­ designer (see Chapter 4). ever, in complex mechanisms, such as timers, where components are small and tolerances are 14-9.2 ELECTRICAL COMPONENTS critical, complete interchangeability is often im­ practical. In these instances, conformance with Electrical components are those electric ele­ the tolerance specifications may be achieved by ments used in the circuits of electric fuzes. selective assembly of parts. Capacitors, resistors, inductors, transformers, switches, transistors, and tubes have special 14-9 COMPONENTS problems as a result of their environment that put stringent requirements on their ruggedness, 14-9.1 SELECTION OF COMPONENTS aging, and temperature characteristics. In addi­ tion, the components must meet many other In many cases, failure of a fu ze component is specifications depending upon the particular a greater calamity than failure of a component: fuze in which they are to be used. in another system. Early activation can cause a personnel hazard. Improper activation results in Components must be rugged enough to oper­ failure of the weapon after other systems have ate after withstanding setback forces, high ro­ done their job. tational forces, and occasionally severe decelera­ tion forces imposed by target impact. To alle When selecting fuze components, the fuze de­ viate these requirements, components can be signer must bear in mind that many components mounted in .a preferred orientation. For ex­ of questionable reliability for long-time applica­ ample, a fuze which is subjected to high rota­ tions may be entirely suitable for use in fuzes. tional forces can have its components so mounted Components with a relatively short operating that the rotational forces operate on their strong­ life or with failure rates that rise sharply with est dimensions. Another solution is to-pot all of cycling might not be usable in other types of sys­ the components so as to add strength to the en­ tems. These components, however, might be quite tire configuration and to give added support to satisfactory for fuzing applications. Even though the wire leads. some fuzes undergo many tests prior to actual use, their total operating life expectancy is nor­ To relieve the effects of aging and thermal mally much less than that of other weapon sys­ changes, three solutions are available: (1) com­ tem components, and they are subjected to far ponents might be used whose original properties less cycling. Similarly, tolerances of some com­ are adequate (to begin with or after bum-in); ponents may prohibit their use in certain types (2) the fuze or the components alone may be of electronic equipment, but they might be used hermetically sealed to prevent excessive damage in an on-off fuze application. from the environmental conditions; or, (3) the components can be so chosen that the variation The factors working against fuze component in one is opposed by that in another. The third reliability vary with the type of fuze with which indicates that careful selection could minimize the components are used. The requirements for the total effect in the circuit. For example, in a long inactive shelf life, extreme environmental simple RC circuit, a resistor whose value in­ conditions while in operation, and the inability creases with increasing tem perature can be to pretest for complete function before use add coupled with a condenser whose value decreases 14-10

AMCP 706-210 with increasing temperature. If the changes in teristics after long periods of inactive storage. these components are comparable, then the net Lubricants, if used, must be carefully chosen effect on the RC time constant is small. (see par. 14-7). In components where the parts require operating clearances, there is the possi­ At present, practical limitations of size and rug­ bility of fret t ing c orr os ion that will inactivate gedness on components limit the maximum time the component. delay possible with RC operated devices to an or­ To relieve the effects of aging and thermal der of magnitude of ten seconds. Resistors are changes, several solutions are available. The fuze or its components may be hermetically sealed, available up to 10’ 2 ohms and capacitors for the components may be chosen so that their fuze circuits are limited to a maximum of 103 performance is more than adequate, or the com­ microfarads. ponent design may be such that any variation m performance with time would be in a non­ An additional problem is introduced with cold critical direction. cathode diodes and triodes. These tubes depend upon light to provide initial ionization. This 14-10 USE OF ANALOG COMPUTER problem has been solved by placing a band of The analog simulation technique is a valuable radioactive material around the tube. The band tool in the design of fuzes. This technique will helps to obtain a consistent breakdown voltage. reduce the number of preliminary tests and will aid in the determination of effects that are diffi­ The choice between a diode and a triode is often cult to evaluate by other means. made on the basis of available energy because a The equations describing fuze behavior are ex­ triode, while slightly more complicated, has more tremely time-consuming to solve without the aid efficient energy transfer characteristics. of a computer. Also, the instrumentation to mon­ itor the performance of various components in Switches must be positive in action, must close proving grounds tests is complex. The usual test every time; should have as low power losses as result determines only whether the fuze func­ possible, i.e., low contact resistance; and should tions or not. remain closed sufficiently long to permit the power source to deliver adequate energy to the In contrast, the analog computer determines circuit. the elemental behavior of the fuze under con­ trolled laboratory conditions where every vari­ 14-9.3 M ECHANICAL COMPONENTS able is easily changed and its influence on each component observed. For example, the effect M echanical components are the operating of different setback forces or the effect of vary­ ing design parameters such as masses or spring mechanical elements used in fuzes. Some exam­ constants can be readily investigated. ples of these components are safing and arming Fuzes of many different types have been an­ alyzed using analog simulation’ 3 '* 5. These fuzes mechanisms, arming rotors, timers, accelerom­ have included components such as mass-spring systems with various types of spring, clockwork eters, and power-operated switches. . mechanisms, dash pots, gear trains, rolling balls, sliders, and rotors. The simulations involve a sub These components differ from the electrical stantial amount of logic elements to account for the various operations such as the movement of components in that they are not usually avail­ a detent a certain distance freeing another com­ ponent and “bottoming and topping” action of able as standard items. It is often required that springs. the fuze designer provide mechanical compo­ Analog simulation is used by the test engineer to provide a more directed and economical test­ nents having characteristics different from those ing program by providing more inform ation about the performance of the fuze. In cases presently in use. In this case it is to his advantage where manufactured fuzes are not functioning as to reap the benefits of previous work in the field 14-11 by starting with the basic features of an existing design having similar characteristics. In this way, the reliability and environmental resistance of the basic design are incorporated into the new design. The mechanical components must be rugged enough to perform reliably and to withstand the setback, rotational, creep, and target impact forces that are imposed. One of the major prob­ lems encountered in the design and application of operating mechanical components in fuzes is that of maintaining the proper frictional charac­

AMCP 706-210 required, sim u latio n can often in d icate th e vario u s p a rts of th e fuze w ere sim u lated and tro u b le d a re a . A lso, w h e re it is d e s ire d to u se solved on the analog computer. p r o v e n fuzes f o r n e w a p p l i c a t i o n s , s i m u l a t i o n is A visual display was set up to show the move m ent of the m ain parts of the fuze. The pictorial useful because any type of setback curve can be d isp la y (Fig. 14-7) u se d c a rd b o a rd cut-outs to simulate moving parts. Time was scaled by a fac­ a p p l i e d to t h e c o m p u t e r “m o d e l” o f t h e fuze. t o r o f 104 (1 0 sec o f c o m p u t e r t i m e r e p r e s e n t i n g Often a change in a fuze component is suggested such as use of a lower cost material. The physi­ 1 m sec of real time) to achieve slow motion. The cal ch a racteristics of th is m a te ria l could affect board aided in visualizing the problem and proved th e fu n ctio n al p erform ance of th e fuze. T his useful in evaluating the design. change can be in v estig ated on th e analog com ­ p u ter, possibly saving need less m an u factu re. T he a rm in g of th e fuze w as stu d ie d for tw o T olerance stu d ies hav e also been perform ed on th e an alo g co m p u ter to d eterm in e w h a t to ler­ d if f e r e n t s e tb a c k f u n c tio n s : (1) a 40-foot d ro p ance ran g e of a fuze co m ponent is p erm issib le without changing the required functioning. te s t, a n d (2) a zone-zero, c h a rg e -z e ro se tb a c k force. I t w as found th a t th e fuze w ould a rm on T he fuze sim u latio n s m entioned above are setback but would not arm in the drop test. typical of th e m an y th a t have been perform ed. 14-11 FAULT TREE ANALYSIS W ith the advent of hybrid simulation, the possi­ bilities for these fuze studies are unlimited. This One of the im portant functions of a fuze or a type of equipment is well suited to these investi­ safing and arming device is to keep the am m uni­ gations because results are immediately obtained tio n item safe to store, h an d le, an d use. T his in a meaningful presentation. W ith the repetitive safety m u st continue after th e item h a s been operation feature of this equipment it is possible placed into use, an d u n til it is safely se p arate d to rapidly optimize a fuze design. from its launcher and no longer presents a hazard to the crew or surrounding friendly troops. A typical application of th e analog sim ulation technique w as th e an aly sis of perform ance of a To te s t en o u g h fuzes of a new d esig n to a s ­ certain its safety features would require so m any p r o p o s e d 8 1 mm m o r t a r f u z e . G i v e n t h e b l u e ­ samples th a t the cost would become prohibitive. To overcom e th is problem , a new m eth o d u sin g p rin ts for th e proposed fuze an d th e w eig h ts of its com ponents, th e eq u atio n s of m otion of th e Figure 14-7. F u z e on Analog Display Board

am cp 706-210 logic diagrams, Boolean algebra, and probability safety of fuzes. values has been developed. This method, known as Fault Tree Analysis, helps to assess the safety 14-12 MAINTENANCE of a fu z e by pointing out the weaknesses of de­ sign, material, manufacturing processes, inspec­ Ideally, fuzes should be completely mainte­ tion procedures, or adverse environmental condi­ nance free. They should be so designed that they tions’ 6 7 . can be placed on the shelf and perform perfectly when withdrawn for use 20 years later. Every An item may fail in several different ways. effort should be made to approach this condition Hence, it is essential that a Fault Tree clearly to produce ammunition having optimum proper­ states the situation to be investigated. Some ties of handling, storage, shelf life, and service typical situations are: ability. (1) Fuze prem aturely detonates projectile Design for maintainability requires incorpora­ during transportation and rough handling. tion of at least the following m aintenance principles’ 8 . (2) S afin g and arming device detonates mis­ sile before minimum safe distance down range. (1) Design to minimize maintenance and sup­ ply requirements through attainment of optimum (3) Fuze prem aturely detonates rocket in durability and service life of materiel. launcher. (2) Recognition of field maintenance prob­ Having selected the situation to be investi­ lems encountered in earlier designed items. gated, the Fault Tree is constructed in diagram­ matic form based on the proposition that a (3) Design for ease of maintenance by as­ logical statement is either true or false, but never suring accessibility to facilitate inspection, re­ , partially true or partially false. These logical pair, and replacement. statements are used to describe a condition which alone or in combination with another’condition (4) Consideration of field maintenance based would cause an event. If several conditions, inde­ on geographical locations and climatic conditions. pendently, can cause an event, the branch is (5) Design for maximum utilization’ of inter­ made through an OR gate. If two or more condi­ changeable components. tions are needed to cause an event, the branch is made through an AND gate. (6) Detection of conditions which will ad­ versely affect the conduct of maintenance op­ When the Fault Tree construction has been erations or generate excessive maintenance and completed, all the contributing conditions are supply requirements. combined by the use of Boolean algebra. Further, each of the contributing conditions can be given (7) Design to effect maximum compatibility a probability value of occurrence. These values of maintenance operations with Contemporary can be actual numbers if sufficient data exist or common tools. the values can be hypothetical, based on engi­ neering judgment. After the values have been as­ (8) Evaluation for ease of packaging, C8T- signed and properly substituted in the algebraic loading, and shipment. expression, final probability number can be de­ term ined for the hazardous condition being (9) Design to enable removal of major com­ scrutinized. ponents as individual units. While not the only method which can be used, (10) Assurance that proper materials and spe-: the Fault Tree technique is considered to be a cial treatment are used for maximum resistance very effective analytical tool in assessing the to deterioration. (11) Consideration of long term storage with a minimum of periodic checks and maintenance in storage. REFERENCES 1. J. J. M cM anus, “Im proving Contact R eliab ility Surface Contaminants on Electrical M a t e r i a l s , in Low -Level C irc u its ,” Electra-Technology 69, 98-101 (1962). Stanford Research Institute, Menlo Park, C a l i f . , Final Report, June 10, 1961, C ontract DA-36- 2. S. W. Chaikin, Study of Effects and Control of 039X-85274, AD-26 1 743. 14-13

AMCP 706-210 REFERENCES (Cont’d) 3. AMCP 706-121, E ngineering Design Handbook, O R D B B -T E 5-20, Dover, N.J., Dec. 1959 (Con­ Packaging and Pack Engineering. fidential). 4. M IL - P - 6 0 4 1 2 , Packaging, Packing and Marking 13. A. G. Edwards, A Performance Investigation o f f o r Shipment o f Artillery Type and Rocket Fuzes, a Proposed 81mm Mortar Fuze Design by Analog General Specification f o r . Simulation M eth o d s (U), P icatin ny A rsenal, Dover, N.J., C o n fid en tial, in “Tripartite Tech­ 5. E. A. S ch atz, “A Survey of Encapsulating Sys­ nical Co-operation Program (U ),” U.S., United tems,” Product Engineering 3 1 , 38 ( I 9 6 0 ) . Kingdom, Canada, Panel 04 (F uzes and In i t i ­ 6. AMCP 706-177, E ngineering Design Handbook, ators), Minutes of Fifth Meeting, Septem ber Properties o f Explosives o f M ilitary Interest. 7. MIL-HDBK-212, Gasket Materials (Nonmetallic), 1965 (Secret). Dept. of Defense, 26 September 1958. 14. I. A. Engle and Edward Lee, Analog Study o f M52 Fuze, P ica tin n y A rse n a l, T ech n ical Memo 8. A. Dam usis, Ed., S ea la n ts, Reinhold P u blish ­ 1776, Dover, N.J., June 1966. ing Corp., N.Y., N.Y., 1967. 15. I. A. Engle and Edward Lee, S im u la tio n o f 9. M. Schwartz, Solders and Soldering Techniques, XM423 a n d X M 427 Fuzes, Picatin ny A rsenal, Diamond Ordnance Fuze Laboratories, (now U.S. Technical Memo 1737, Dover, N.J., June 1966. Army Harry Diamond Laboratories), Report R53- 16. W. F. Larsen, F ault Tree A n a ly sis, Picatinny 57-43, Woshington, D.C., 18 November 1957. Arsenal, Quality Assurance Directorate, A R D I P 10. R. M els and W. Roeser, Solders and Soldering, No. 20, Dover, N.J., Aug. 1968. National Bureau of Standards, C ircular 492, 17. M ax in e Bohacz, et al., A Guide to Developing Washington, D.C., 28 April 1950. Safer and More Reliable Fuzes, Picatinny Arse­ 11. The Lubrication o f Ammunition Fuzing Mecha­ nal, Technical Report 3795, Dover, N.J., Oct. nisms, Journal Article 49.0 of the JANAF F u ze 1968. Committee, May 1967, AD-829 739. 12. J. C. Howell, Design o f Tuze, P IB D , T 199E 6 18. AMCP 706-134, Engineering Design Handbook, ( V ) , Picat inny Arsenal, Technical Memorandum M aintainability Guide f o r Design, Chapter 28. 14-14

AMCP 706-210 CHAPTER 15 FUZE TESTING 15-1 GENERAL th a t lacks one or more components of the entire fuze is o ften co n stru cted for d evelopm ent te s t­ Throughout the development of a fuze, the de­ ing. S om etim es a special com ponent is su b sti­ sig n er su b m its each co m p o n en t to d ev elo p m en t tuted for the purpose of facilitating the test of a te s ts to an sw er th e question: D oes th is com po­ p a rtic u la r fuze fun ctio n or action. To te s t a rm ­ nent act in the m anner for which it is designed? ing distance, for exam ple, th e designer m ay re ­ W hen the prototype of the fuze is built, it is sub­ place th e explosive tra in by a fla sh ch arg e th a t jected to p erfo rm an ce o r proof te s ts in o rd er to ignites when the arming process is completed. In answer the question: Does this fuze satisfy its re­ acceptance tests, on the other hand, the fuze can­ quirement&? Since these tests often destroy the not be so modified. Here, th e fuze is presum ed to fuze an d since th e av a ila b le n u m b e r of fuzes is have arm ed w hen it functions a t th e targ et. A lim ited , it is n ecessary to ap p ly special m eth o d s separate acceptance test is required to check the of an a ly sis to th e te s t d a ta . T h ere is a definite safe arming distance. tre n d to w a rd sta n d a rd iz a tio n so th a t sp ecial a t­ (2) D e v e lo p m e n t te s ts a re o fte n m o re p r e ­ tention is given to standard tests (see Table 15-5 cise or more severe th a n acceptance tests. Rather than stop at the required limit, the designer pre­ in p a r. 15-5). T h e re are, h o w ev er, m a n y e s ta b ­ fers to te st a given p a rt until it is destroyed so as lished procedures th at can serve in the absence to acquire useful design data. For example most of a standard (see Journal articles, Appendix II). fuzes are accepted if th e y w ith sta n d 1750 jo lts in each of three positions on a standard machine. 15-2 PERFORMANCE TESTS However, the designer may profit from the knowl­ edge th at his fuze withstood 5 tim es th at number Fuzes are tested in various ways to determine of jolts. A s an o th er exam ple, in th e arm in g te s t whether they operate as intended, whether they mentioned above, a flash charge perm its the de­ are safe, and w hether they w ith stan d different signer to locate the distance at which the fuze be­ en v iro n m en ts. P erfo rm an ce te sts include bo th cam e arm ed , n o t m erely to d eterm in e th a t it th o se concerned w ith o p eratio n of th e com plete arm ed w ithin a certain zone. T hese exam ples fuze and of the individual components. Common show how a test can indicate the marginal point, or standard tests are described and typical labora­ i.e., th e p o in t w here en g in eerin g ju d g m en t can tory program s for te stin g fuzes during develop­ be effective in specifying further refinement. m ent phase or acceptance phase of the fuze de­ sign are suggested. It is necessary to include test (3) D e v e lo p m e n t te s ts a re sp ecified b y th e pro g ram m in g in th e in itial p lan n in g for a fuze designer; acceptance tests, on the other hand, are developm ent project. specified by a Service Board. This arran g em en t perm its an evaluation by an independent engi­ 15-2.1 DEVELO PM ENT A N D ACC EPTAN CE TESTS neering agency. The designer will always test the complete fuze to ascertain th a t the modifications D evelopm ent te sts are perform ed to evaluate he h a s in tro d u ced do n o t adversely affect its t h e d e s i g n e r ’s l a t e s t e f f o rt; a c c e p t a n c e t e s t s a r e o v erall p erfo rm an ce. H ow ever, since ju d g m e n t p erfo rm ed to e v a lu a te th e fin al d esig n a n d are governs the type of tests selected and the num ber often called app ro v al te sts or ev alu atio n tests. of sam ples chosen, fin al acceptance te sts m u st Development tests seek an answer, while accept­ confirm th e fact th a t th e fuze does p erfo rm as ance te sts confirm it. T he te s ts are sim ilar, y et specified. they differ in three respects: 15-2.2 TEST PROGRAMMING (1) D e v e lo p m e n t te s ts a re a p p lie d to in d iv i­ dual components, to modified fuzes or to the en­ B efore an y te sts are m ade, a te st program tire fuze; acceptance tests are applied to the en­ should be set up to include appropriate tests for tire fuze only. A m odified fuze or a te s t m odel 15-1

AMCP 706-210 each component and for the entire fuze. Each detents, springs), a n d (3) pow er sources th at provide the energy needed to initiate the first ex­ program should be adapted to the particular plosive element. The tests described below are fuze being designed. A sample program of safety concerned with performance and simulate actual and surveillance is shown in Table 15-l. It is rec­ conditions satisfactorily. om m ended that schedules of this sort be set at the start of a developm ent program . Such plan­ 15-2.3.1 (Explosive Elements ning will avoid wasting fuzes in over-testing and will permit sequential testing when desired. For Since fuzes m ust function, explosive com po­ any particular fuze design, some of these tests nents are the key parts. They are tested singly or m ay be om itted while other more appropriate in combination with other elements of the train. ones may be added. It is important that the sam­ Component tests are normally divided into three ple size be sufficiently large that the conclusions partsinput, output, and train continuity-where are valid (see par. 15-6). the last one is really a com bination of the other two. The order of tests m ust be considered care­ fully. Sometimes, the order is one of m ere con­ For stab and percussion detonators and prim­ venience; at other times, a definite order is essen­ ers, input is simulated by dropping onto the fir­ tial. G enerally prior to firing tests, a particular ing pin a ball of a known weight from a measured fuze design should be subjected to a variety of height. Flash detonators and other flash initiated rough handling tests to insure that it is safe while components are set off with a standard primer of being handled by proving ground personnel. It is the particular train. Electric detonators are ini­ most desirable to perform sequential tests where tiated from te st sets that simulate the charac- the same fuze is subjected first to one test, then teristics-such as voltage, current, capacity, and to another. In this w ay, cum ulative effects m ay duration-of the planned pow er source. be evaluated'. It is necessary to have extra fuzes- 15 is a typical quantity-for com parison p u r­ There are several explosive output tests but as poses. These are inserted as controls at various yet there is no definite agreem ent as to which stages in the sequential test. test most aptly indicates the ability of a compo­ nent to transm it detonation to the next com- T A B LE 15-I. S AFETY A N D SU R VEILLAN C E TESTS ponent=. W hile absolute results of these tests m ay be in doubt, they are a good yardstick for MIL-STD-331 Typ rca 1 quality assurance and for measuring the effect of minor changes. In the sand bomb test, the deto­ Test Test No. Quant rty nator is set off in a prescribed fixture w here it crushes sand of a specified grade. The amount of Jolt 101 6\" sand crushed is a m easure of output (see par. Jumble 102 6 4-2.3). In the lead disk test (MIL-STD-331, Test Five-foot drop 302), the deto n ato r is placed on top of a speci­ Forty-foot drop 111 10 fied disk (usually Grade B lead sheet, 0.1345 in. 103 10 thick and 1% in. diam eter). The size of the hole Transportation vibration blow n through the disk is a m easure of output. Temperature and humidity 104 10 In the steel d e n t test (MIGSTD-331, Test 301), Vacuumsteam pressure 105 5 the detonator is placed within a prescribed sleeve 106 5 on top of a specified size steel block. The depth Waterproofness of the dent is a measure of output. Depths range 108 5 from 0.005 to 0.100 in. Salt spray 107 2 The explosive train continuity test determines whether each component in the train will be ini­ * Sequential in 3 positions tiated and w hether the final detonation will be sufficient for its purpose. D uring this test, the i-------------------------------------------------------------------------------------------------------------------- 1 components may be assembled in line (the armed position) in either a fuze or a test fixture. In cases 15-2.3 COMPONENT TESTS where different triggering actions (impact, time, graze) set off separate trains, each train must be The performance of most components is tested by means other than firing, although firing tests are used occasionally. In addition to housing parts, com ponents m ay be divided into three groups; (1) explosive elem ents, (2) m echanical devices that m ust be displaced (rotors, sliders, 15-2

a m c p 706-210 te ste d individually. T est re su lts w ill be m ore A centrifuge consists of an arm or p late ro ­ meaningful if the actual rather than some simu­ ta ted about an axis. Its principal use is for sim u­ la te d te sts in d icate b u t do n o t g u a ra n te e field la tio n of setback. T he fuze or its p a rts can be perform ance. In addition to learn in g w h eth er a m o u n ted in v ario u s positions on th e arm of th e train functions, it is often desirable, particularly centrifuge as shown in Fig. 15-2. It can be seen when delay elements are used, to know how long f r o m E q . 5 -1 1 ( F c = Wp r « 2/ g j t h a t b y r o t a t i n g it ta k e s th e fuze to function. F u n ctio n in g tim e the centrifuge arm, a force is exerted on the part. may be m easured on an electronic counter started The equation also shows th at when the radius r w ith a n im p u lse from th e in p u t device an d is large, the angular rotational velocity m m ust be stopped by a tran sd u c er th a t picks up lig h t or kep t sm all so th a t th e forces will not exceed the ionization of the output flame. p hysical lim itatio n s of th e equipm ent. M any novel and valuable techniques have been applied T he sta tic d e to n a to r safely te s t (M IL-STD - to these centrifuges, such as: (1) optical systems 331, T est 115) determ ines w h eth er th e re st of to observe th e p a rt during th e test, (2) slip rings th e tr a in w ill be se t off w h en th e d e to n a to r is to ta k e off s ig n a ls fo r d a ta re c o rd in g , (3) d a ta initiated in the unarm ed position. Results of this storage systems to be carried on the rotating arm, te s t are in a sense d irectly opposite to th o se of a n d (4) telem etering system s using high frequency th e la st nam ed test. The fuze or test fixture m ust radio waves. The acceleration-time patterns may be modified so th a t the detonator m ay be in itia­ be programmed for the part. Since the centrifugal ted in the safe position. A typical modification is forces d ep en d u p o n th e ra d ia l d istan ce to th e sh ow n in Fig. 15-1. T he te s t is su ccessfu l if no part, th a t force changes if th e p a rt moves radially explosive p art beyond the arm ing device chars or but not if it moves perpendicularly to the radius. deform s and th ere has been no hazardous ejec­ H ence, by p ro p er fix tu re design, th e effects of tion of p arts. axial accelerations (propulsion), lateral accelera­ tio n (steering), an d rollin g acceleratio n s can be T ypical q u a n titie s are te n for each explosive sim u lated an d m easu red . Since th e stre n g th of train continuity and detonator safety tests. th e te s t device lim its th e size of th e sp ecim en th a t m ay be m ounted, cen trifu g es are b u ilt in It may also be desirable to measure the c o o k ­ various sizes w ith approximate extrem es as given off tem perature of the explosives as described in in Table 15-2. JA N A F Jo u rn a l A rticle 43.0 (see A p p en d ix II). A sp in m ach in e is u se d to sim u late th e sp in ­ TEST firing pin n in g of a fuze in flight. In th is te st, a fuze is m o u n ted on an arb o r an d sp u n a t th e req u ired TEST TRING PIN GUIDE speed. I t can th e n be ascertain ed , for exam ple, fULE FIRING PIN w h e th e r a ro to r d o e s n o t t u r n a t th e nonarm * THIS HOLE IS DRILLED IN FUZE BODY IN ORDER TO INITIATE THE DETONATOR lim it (say, 1500 rpm ) b u t does tu rn a t th e arm IN THE UNARMED POSITION. lim it (say, 2100 rpm). M easurem ent is by m eans of a light shining through the detonator hole in fig u re J5-1. Arrangement for Detonator Safety Test th e ro tor or by m ean s of a probe, depending on fuze construction. The movement of other parts, 15-2.3.2 Mechanical Devices such as detents, under the influence of spin can also be determ ined by this machine. Instrum en­ Centrifugal or setback forces th a t are encoun­ ta tio n sim ilar to th a t u sed w ith cen trifu g es is te re d by a fuze can be em ployed to m ove m e ­ em ployed. chanical devices. These forces are sim u lated for te st conditions by centrifuges, spin m achines, Setback forces may be sim ulated in a drop test air guns, and other miscellaneous devices. fixture or, more conveniently, in an air gun. The a ir g u n is a sm o o th b o re c a n n o n w ith a high- p re ssu re a ir ta n k a tta c h e d to th e b reech an d a long pipe ex ten d in g from th e m uzzle. O ne type of a ir g u n o p e ra te s as follow s: w h en a v alv e is opened, a p iston w ith th e te st com ponent a t­ tached is propelled through tube and pipe against a target. A velocity of 750 fps has been reached 15-3

AMCP 706-210 F ig ure 15-2. Low -g C entrifuge T A B LE 15-2. DIMENSIONS OF PRESENT DAY assurance inspection of fuzes in production. CENTRIFUGES A shock m a ch in e covers th e ra n g e of low a c ­ Type A cceleration, Specimen weight, A r m Length, celeratio n s, below those of drop te sts an d air lb gu n s. Fig. 15-3 show s a h y d rau lic shock m a ­ g ft chine-in its concrete te s t p it-h av in g a ran g e of o to 3 0 0 0 4 5 0 0 0 g. I t is u s e d to t e s t g r a z e i m p a c t Low g 100 100 14.6 sensitivity, fuze load during automatic ramming, High g 60,000 1 1.5 or setback in a m o rta r tube. It can operate on controlled start or stop of the piston. Piston mo­ in air guns. One advantage of both centrifuge and tion is controlled by a series of valves to vary the air gun tests over a firing test is the fact th at the shape of the shock. specimen may be examined afterwards. Auxiliary instrum entation is provided in the form of high R ocket sleds, th a t now ap p ro ach hypersonic speed cameras and strain gages. For impact tests v elocities, are u se d for tw o p u rp o ses in te stin g in an air gun, the instrum entation can be greatly fuzes and am m unition: (1) w ith th e sled fired in simplified if the specimen is mounted stationary the same direction as the projectile, the relative velocities of sled an d projectile can be ad ju sted a t th e ta rg e t position an d a sim u lated ta rg e t for projectile recovery in excellen t condition, fastened to the piston is shot against it. a n d (2) w ith o p p o sin g v elo cities, p e rfo rm a n c e u n d e r ex trem ely h ig h velocity im p a ct can be T est q u a n titie s v ary w ith req u irem en ts. Five assessed. to ten item s are a reasonable sample size fcr air gun tests. If th e item s are n o t dam aged in the P a ra c h u te recovery m eth o d s are u sefu l in te st, th ey can be used rep eated ly . B oth air gun te stin g fuzes. M issile fuze sy stem s th a t o p erate and centrifuge tests also lend themselves well to on b u rs t h e ig h t m ay be allow ed to go th ro u g h operability tests at extreme temperatures. the firing sequence w ith subsequent parach u te dep lo y m en t an d in ta c t recovery. H ypersonic S ince cen trifu g e an d sp in te sts m ay be non­ rockets, mortars, and bombs may be used as test destructive, developmental fuze samples are fre­ v eh icles for fuze com ponents. T h e vehicle body q u e n tly so te ste d before a n d a fte r o th e r te stin g as applicable. These tests are also used in quality 15-4

AMCP 706-210 Transducers in the device being tested convert the variable being measured into an electrical sig­ nal that is subsequently used to m odulate the carrier of an RF transmitter. M odulation in­ volves changing the am plitude, frequency, or phase of the carrier. The signal is received, ampli­ fied, and dem odulated on the ground and re­ corded on magnetic tape or on an oscillograph for subsequent analysis. If developm ent tests appear to w arrant tele­ metering, it is well to seek guidance from some­ one familiar with equipment and facilities of the test area being considered for use. 15-2.3.3 (Power Sources Figure 15-3. Shock Machine Fower sources require special tests only occa­ sionally. W hen the source is a mechanical trans­ contains the parachute and deploym ent mecha­ ducer, such as a spring or a rotor, it is tested like nism in addition to the fuze com ponent under any other mechanical device. H ydraulic sources test. may require pressure tanks or wind tunnels if the medium is air or a gas. Electric sources, as well as Telemetering in the broad sense involves the auxiliary electric circuit components, are tested transm ission of data by any m eans from a re­ as breadboard m odels in conventional ways. In mote and usually inaccessible point to an access­ all instances, the final test must establish that the ible location'. Usually, telem etering refers to pow er source can set off the prim er, or detona­ electrical m eans of acquiring and transm itting tor, in the particular fuze. data, transmission usually being accomplished by m eans of an RF link from the m unition to a 15-2.4 PROOF TESTS ground station. The requirement for telemetering data from fuzes may be quite severe, as in the The performance of a final design for a fuze artillery fuze where survival of the telemetering is evaluated by actually firing a complete round transmitter, power source, and antenna is essen­ containing the new fuze; this is called a proof tial u n d e r accelerations in excess of 50,000 g test. Firing tests are not only a pow erful check during setback. A typical system m eeting these on the validity of sim ulated tests, b u t they also requirements is shown in Fig. 15-43 . On the other perm it a check on performance of the complete hand, the telemetering equipm ent in rockets, fuze w hen subjected to the total environm ent bombs, and grenades need not be as rugged al­ that it will experience. The proof test is the only though size and weight might be critical. m eans of evaluating final assembly operations and possible effects of force com binations that Often in military applications, a simple yes or were not apparent when individual components no response will provide answers that will isolate w ere subjected to single forces one at a time. troublesome portions of the fuze in development Table 15-3 enum erates the type of inform ation programs. Simple modifications of the m unition that can be determined by proof tests. may give a light flash or a puff of smoke that can be detected by a hum an observer or by a de­ Proof tests have not been standardized to the tecting device. How ever, for variable data such same extent as other tests because they m ust be as acceleration, strain in a member, or rotor posi­ adapted to individual requirem ents that vary tion, conventional RF telem etering is necessary. w idely. It is, therefore, not possible to describe individual tests in detail. Test conditions, equip­ ment, quantities, and m ethods of analyzing re­ sults differ from fuze to fuze. The basic concept of the proof test is: A fuze 15-5

AMCP 706-210 M IXEIR RADIO FREQUENCY OSCILLATOR SUBCARRIER Ol REGULATED POWER OSCILLATOR+ y INERTIA SUPPLY , SWITCH .. i , IN- FLIGHT - CALIBRATOR PREAMPLIFIER REGULATED POWER SUPPLY ANTENNA SENSOR RADIO FREQUEN SUBCARRIER OSCILLATOR Figure J5-4. Typical VHF High-g T elem etry System T A B LE 15-3. TYPIC AL FIELD PROOF TESTS bility is not required. Here, the design is accept­ able even though the fuze may be damaged pro­ ARM IN G DETAILS* vid ed no explosive elem e n t p a s t th e safety d e­ vice fu n ctio n s, th e fuze does n o t arm , a n d it is A rm ing distance safe to dispose of thereafter; A rm ing tim e Parachute delivery (2) Nondestructive tests are those where op­ erability is required. Here, the design is accept­ FUNCTIONING DETAILS* able only w hen the fuze is not harm ed and “su r­ vives” the test by virtue of fu n c tio n in g afterward Dependent upon Target Independent o f Target as intended. Specific tests are listed b e lo w and a suggested te st program is given in par. 15-2.2. N orm al or oblique im pact C lockw ork P e n e tra tio n F luid flow 15-3.1 DESTRUCTIVE TESTS D elay Pressure (for m ines) G raze action Drop, jolt, and jumble tests check the rugged­ S ensing (for proxim ity fuzes) S e lf-d e stru c tio n ness of a fuze and measure the sensitivity of ex­ Manual disturbance R ain and snow plosive components when subjected to severe im­ pacts. Drop tests sim ulate the effects of free fall * Proof tests should be made both at ambient and of fuzed items of am munition during handling or extrem e tem peratures. transportation. It is advisable to perform tests at e x tre m e te m p e ra tu re s (-65” to 160°F) in o rd er is te ste d a t all conditions sim ilar to those u n d er to find out whether the m aterials or the compo­ which it is expected to perform. nents are vulnerable at these temperatures. 15-3 SAFETY TESTS T h e 4 0 - f o o t drop test ( M IL - S T D - 3 3 1 , T e s t 103) sim u lates a severe condition th a t m ay be S afety tests, d esig n ed to in v e stig a te th e re ­ m et during norm al handling. A m m unition w ith q u irem en ts for safe h an d lin g as given in p ar. live fuzes is dropped in free fall onto a steel plate 9-2.2, a r e o f tw o ty p e s : (1) D e s t r u c t i v e t e s t s a r e t h o s e :w h e r e o p e r a ­ . 15-6

AMCP 706-210 on a reinforced concrete base. T he sev erity of drop te sts is d e m o n stra te d in th e acceleration - t i m e t r a c e s r e p r o d u c e d i n F ig . 15-54. F iv e d i f ­ ferent striking orientations are used: nose down, base dow n, horizontal, axis 45” from v ertical w ith nose down, and axis 45” from vertical with n ose up. Fig. 15-6 is a p h o to g ra p h of a 40-foot drop tow er. N o t ju s t a m ere tow er, a fuze drop tower requires m any accessories for am munition hoisting and observation. Figure 75-6. 40-ft Drop T ow er Figure 75-5. Acceleration Experienced by 81 mm Mortar Projectile Dropped Base Down T h e jolt t e s t ( M I L - S T D - 3 3 1 ,T e s t 1 0 1 ) r e q u i r e s Figure 75-7. Jolt M ac h in e th a t th e sam ple fuze be jolted or bounced 1750 tim es in each of th ree positions. T his te s t is de or p arachute delivery), an d (2) not as planned (ac­ signed to expose th e m o st v u ln e ra b le p lan e of cidental m issile release during take-off or lan d ­ w eakness. A photograph of the appropriate te st ing). Several te sts have been stan d ard ized th a t machine is shown in Fig. 15-7. D uring the devel­ sim u late such fall from aircraft. F o r exam ple, opment phase, tests are sometimes continued un­ je t t is o n tests m a y b e p e rfo rm e d in one o f fo u r til destruction to gain additional design informa­ w a y s (M IL -S T D -331, T e s ts 201-205): (1) d ro p tion. O n th e o th e r h an d , m an y d esig n ers re ­ from a irc ra ft (for m u n itio n s th a t a re released ), quire o p erability after b o th sta n d a rd jo lt an d (2) la u n c h e d fro m a irc ra ft (for m u n itio n s th a t jumble tests. a re fired ), (3) s im u la te d a irc ra ft d ro p b y firin g from a ground launcher into a sand filled bin a t a I n t h e ju m b le te s t ( M IL - S T D - 3 3 1 , T e s t 102), velocity th a t approximates the term inal speed of fuzes are tu m b led in th e ap p ro p riate m achine. 16-7 T his te s t estab lish es th e basic ru g g ed n ess of a fuze design. The m achine (Fig. 15-8) consists of a w ood-lined steel box w h ich is ro ta te d ab o u t two diagonal comers a t 30 rpm. I t sh o u ld be n o te d th a t sh a p e a n d size of th e fuze being ju m b led are im p o rta n t factors an d may cause the machine to record shocks different from those experienced by the fuze in actual use. A ircraft m ay drop am m unition w ith unarm ed fuzes for two reasons: (1) as planned (jettisoning

AMCP 706-210 FUZE PLACED *■ TW O J U M B L E BO XE S !N Bo x Figure 15-8. Jumble Machine a high-altitude drop, and (4) simulated aircraft Test 208) determines the distance from the launch by firing from a ground launcher. In all weapon within which the fuze will not function cases, arming wires are left in place and the fuze as a result of impact if free to arm. This test is must not explode after dropping. Tests like these performed under the same conditions as those are becoming more popular and are expected to for the muzzle impact test except that the target become more applicable to all types of military is placed at several positions near the minimum distance specified in design requirements. The items. percentages that function are determined at each The acciden tal release (low a ltitu d e , hard position along the range. Fig. 15-9 shows a typical curve of results for a 20 mm fuze. surface) t e s t (MIL-STD-331, Test 206) is used to determine whether fuzes assembled to muni­ The missile pull-off from aircraft test (MIL- tions released from an aircraft during take off or STD-331, Test 209) is to test the field safety landing will remain safe after hard-surface impact. during arrested landing. It is used to assure that the fuze will undergo impacts in the unarmed The need for this test arises from the possibility that the malfunction of an aircraft or its release condition equivalent to those that might be re­ equipment (occurring during or immediately after takeoff or landing) could accidentally re­ ceived if the munition were to strike a hard sur­ face after accidental release during arrested lease or necessitate the release of munitions. landing. The m u z z le i m p a c t test (MIL-STD-331, Test The time-to-airburst test (MIL-STD-331, Test 207) determines whether a fuze is bore safe. 210) is an operational test used to determine the This test is performed under actual conditions but timing error of the fuze under field firing condi­ with inert missiles. A target that reliably initiates tions. It consists of firing a time fuze, assembled the fuze is placed as close as feasible to the to an appropriate explosive loaded projectile, set muzzle. to function at a predetermined time. The time to The impact s a f e d i s t a n c e test (MIL-STD-331, 15-5

AMCP 706-210 burst of the fuze is determined by measuring the also tested for safety in the event of a malfunc­ time of flight of the projectile from the weapon tioning parachute. to the point of burst. Some of the systems used to measure time to air burst are stop watches, The catapult and arrested landing test ( M I L - electric clocks, and fuze chronographs. STD-331, Test 212) is needed to assure that fuzes can withstand catapult takeoff and arrested 100 landing forces and yet remain safe to transport, handle, and store, as well as remain in operable 80 condition. The fuze is assembled, unarmed, in 20 the inert-loaded munition for which it is designed or in a suitable test fixture. The test item is cata­ 0 pulted or accelerated to obtain the acceleration 50 time patterns required. Each accelerated fuze is examined for evidence of unsafe conditions. DISTANCE UNITS The tra n sp o rta t ion vibration test ( M I L - S T D - F ig u re J5 -9 . R esults of I m p a c t S afe D is ta n c e Test 331, Test 104) consists of vibrating sample fuzes according to a specified schedule of frequencies, 15-3.2 NONDESTRUCTIVE TESTS amplitudes, and durations. They are vibrated both in and out of their shipping containers. In These tests check the permanence, ruggedness, this test, fuzes are accepted if they show reason­ and reliability of the fuze safety features by simu­ able wear but they are rejected if seriously lating a wide variety of actual handling and damaged. Engineering judgment and laboratory transportation conditions such as vibration and or field testing determine whether borderline short drops. Some designers also require opera­ damage is likely to affect safety or operability. bility after jolt and jumble tests. These are de­ scribed in the foregoing text. A number of tests The equipment for this test consists of a s p r i n g - deliberately exaggerate the conditions to which mounted table having an adjustable, imbalanced, the fuze may be exposed. Often these tests are rotating weight attached to the underside. A re­ performed in sequence to make sure that cumu­ mote control system regulates the vertical mo­ lative effects of the tests do not weaken the fuze. tion of the table by shifting the rotating weights and manual control of the motor speed regulates The parachute drop test (MIL-STD-331, Test the frequency of vibration. A photograph of the 211) is a field test to determine whether the fuze transportation-vibration machine is shown in will remain safe and operable after subjection to Fig. 15-10. the forces incident to parachute delivery. It con­ sists of dropping, from an aircraft, fuzes in pack­ The 5-fo o t drop test(MIL-STD-331, Test 111) ages to which parachutes are attached. Fuzes are simulates severe shocks encountered during acci­ dental mishandling in transportation or service use. Fuzes (assem bled to their inert-loaded carrier) are dropped 5 feet on to a concrete sup­ ported steel plate. Five different striking orienta­ tions are used: (1) nose down, (2) base down, (3) horizontal, (4) axis 45” from vertical, nose down, and (5) axis 45” from vertical, base down. The 5-foot drop test differs from the 40-foot drop test which is solely a destructive test at an extreme condition. After the 5-foot drop test, the fuze must perform as intended. The rough handling test (MIL-STD-331, Test 114) simulates rough handling which may be en­ countered by fuzes during transportation and handling while in the standard packaged condi­ tion. The test consists of subjecting the packaged fuzes to vibration, free fall drops, and recurring impacts. 15-9

AMCP 706-210 Figure 75-70. T ra n s p o rta tio n -v ib ra tio n M a c h i n e m etals corrode m ore easily in the presence of moisture, the problems of m oisture sealing and 15-4 SURVEILLANCE TESTS surface treatment are paramount. Corrosion is re­ duced by plating and sealing. Since a coating also Surveillance is the observation, inspection, in­ seals in any entrapped moisture, a small amount vestigation, test, study, and classification of am­ of silica gel as an absorbent has on occasion been m unition, am m unition components, and explo­ inserted in each fuze. In certain instances, fuzes sives in movement, storage, and use with respect are filled w ith an inert gas such as freon. Poly­ to degree of serviceability and rate of deteriora­ sulfide rubbers and epoxy resins are representa­ tion. Since fuzes m ay be kept in storage over a tive of sealing materials. Each has certain quali­ number of years, they require surveillance at their ties that make it suitable for the different compo­ place of storage to determine their serviceability nents of a fuze. at any given time. Tests to detect physical and chemical changes as well as to check operability Of all fuze parts, the explosive components are perform ed at intervals of six m onths or a are the least stable so that precautions should be year. taken to insure their operability over an ex­ tended period. It is expedient to conduct accel­ 15-4.1 FACTORS AFFEC TING SHELF L IF E erated tests under simulated conditions because Fuzes are adversely affected by corrosive at­ the storage interval is m easured in years. Some mospheres and extreme heat or cold; but the two indication of the deterioration can be obtained m ost destructive factors are m oisture and fire. if tests are carried out at high tem perature and Protective coatings are used to decrease the for­ weight loss, gas evolved, time until nitrogen ox­ m ation of harm ful chemical combinations. Pro­ ides appear, and ignition temperature are meas­ tection against fire is best afforded if the packing ured. cases are constructed of m etal instead of wood. The designer should keep these basic concepts in For example, the rate of gas evolution is given mind: (1) the fuze should be as moistureproof as in Table 15-4 for equal weights of some common possible, an d (2) the explosive com ponents an d explosives. These values indicate the chemical the methods of loading should be such that long stability of the explosives from which their per­ storage of the fuze, either alone or assembled in formance may be deduced. Lower values are pre­ loaded projectiles, w ill not result in deteriora­ ferred and all up to 5 ml are acceptable. tion or in form ation of sensitive chemical com­ pounds. If hermetically sealed cans are used, T A B L E 15-4. V O LU M E OF G AS EVO LVED IN 40 many problems do not arise. HOURS IN V A C U U M A T 120°C Since explosives deteriorate more rapidly and 50/50 Am atol 4.53m l Tetryl 2.98 16-10 Explosive D 0.52 TNT 0.44 15-4.2 ACCELERATED ENVIRONMENT TESTS The fuze designer should get advance informa­ tion on how well his fuze will w ithstand the ef­ fects of storage by subjecting it to accelerated tests of salt spray, humidity, temperature, moist­ ure, and fungus. Since long-term tests cannot be tolerated during developm ent, severe environ­ m ents are used for a short period to simulate milder environm ents over extended periods; hence, the tests are accelerated. All environm ental tests are perform ed w ith bare fuzes containing all of their elements. The

AMCP 706-210 tests are nondestructive, i.e., the fuzes must be Figure 15-12. Cooling and Heating Curves of both safe and operable after the tests. F u z e s Subjected to the Temperature and Humidity Test The salt spray (fog) test (MIL-STD-331, Test 107) is used to ascertain the extent to which the of fuzes to withstand prolonged storage at ex­ fuze is waterproof and corrosion resistant. The treme temperatures. The test consists of placing test consists of exposing bare fuzes to a salt spray the fuzes in a temperature chamber at -65°F atmosphere continuously for 48 hours to check for 28 days, followed by exposure at 160” F for an additional 28 days. operability and for 96 hours to check safety. The fuzes must be safe following the 9 6 -h o u r test but The vacuum-steam-pressure test (M IL -S T D - both safe and operable following the 48-hour 331, Test 106) simulates tropical climates. It is test. Many times, individual components are re­ especially important for fuzes that contain elec­ quired to be able to pass a similar test as a quality trical components. The test has been found to be control check on their protective coatings. the equivalent of about eight months storage in the Pacific. Each sample fuze is exposed to 1000 A schematic layout of the test chamber and consecutive, 1 5 -m in u te cycles in a vacuum-steam- the orientation of the fuzes to be tested is shown pressure chamber. Fig. 15-13 shows a typical in Fig. 15-11. installation. The standard temperature and humidity test (MIL-STD-331, Test 105) is considered to be best for use during development of fuzes. The test involves exposing bare fuzes to two identical 14-day cycles for a total of 28 days. During these periods, fuzes are heated to 160°F and then cooled to -65°F nine times. A relative humidity of 95 percent at the high temperatures is used to accelerate the damage. Static and oper­ ational tests under field conditions are used to determine whether the fuze withstood the test. Fig. 15-12 shows average heating and cooling characteristics of fuzes subjected to the tempera­ ture and humidity test cycle. The extreme temperature storage test (M IL - STD-331, Test 112) is used to check the ability A X E S OF A L L FUZES A R E IN THE P L A N E P A R A L L E L TO LONS S I D E S OF C H A M B E R SPRAY N O ZZLES -AIR SUPPLY TO FOG NOZZLES ■FOG __ AIR SATURATOR COLLECTOR 1111 Figure 75-7 1. Layout o f Salt Spray (Fog) Chamber

AMCP 706-210 Figure 15-13. Vacuum Steam Pressure Chamber In the w a te r p r o o f n e s s te st (M IL -S T D -33 1, The therm l shock test (MIL-STD-331, Test Test 108), fuzes are immersed in water to de­ 113) consists of subjecting the fuze to thermal termine their ability to withstand water pene­ shocks (three hot and three cold) between the tration. After soaking for one hour in water con­ temperatures of -65” and 160°F within 2 hours taining a fluorescent dye, they are examined to determine whether the fuzes will withstand under ultraviolet light for evidence of moisture. the effects of sudden changes in temperature. The rain exposure test (MIL-STD-331, Test In addition to these more common tests, the 109) is intended to simulate field operations to fuze may be subjected to other environmental which the fuze might be subjected during stor­ conditions that it may encounter; e.g., the cold age in rainy weather. The test consists of placing and dryness of the polar regions and the low- bare fuzes in a test chamber where a water dis­ pressure, cold air streams at high altitude. Pro­ tribution system, generally simulating rainfall, cedures are available to test effects of sand and causes droplets to fall upon the test fuzes. dust, solar radiation, low pressure, and sensi­ tivity of the fuze to rainfall’ . A number of rain The fungus resistance test (MIL-STD-331, Test simulation techniques have been developed6 ; a 110) consists of exposing bare fuzes inoculated with fungi to conditions conducive to fungus description of a simulated rain field test facility growth to determine if fuze performance is ad­ follows7. versely affected by this environment. The ap­ pearance of fungi on the fuze is not in itself a A simulated rain field (located at Holloman cause for rejection, unless the growth could con­ Air Force Base, Alamogordo, New Mexico) has ceivably interfere with the safety and operability been successfully used in testing for rain sensi­ of the fuze. In this respect, this test differs from tivity and erosion of point-detonating fuzes. tests designed to evaluate fungus resistance pro­ Functioning of various standard PD fuzes (not perties as such. desensitized against rain functioning) has been induced by firing the fuzes’from cannon or by 15-12

AMCP 706-210 transporting the fuzes on rocket-propelled sleds fuzes and fuze components. It is the purpose of through the simulated rain field. Velocities from the safety tests to detect unsafe conditions and 1500 to 2700 ft/sec appear to be the critical to make sure that fuzes will not break, deform, range for fuze functioning. Functioning at higher arm, or become otherwise dangerous to handle velocities can also be realized, however, approx­ or use. It is the purpose of the operation tests to imately 3000 ft/sec seems to be the limit for determine whether a fuze operates satisfactorily most present day artillery munitions requiring during and after a given set of conditions, and to point-detonating fuzing. A typical rain field is make sure that fuzes arm, penetrate targets, created by placing water spray nozzles parallel to destroy themselves, and otherwise function as the line of fire or parallel to the rocket sled rail intended, at a suitable height and angle. Water is supplied to the nozzles at the pressure which will produce MIL-STD tests on fuzes are divided into three the desired amount and size of water droplets. main categories (1) Laboratory, given the 100 Availability of water in sufficient volume and series of test numbers; (2) Field, given the 200 pressure is critical. The density of large rain drops series of test numbers; and (3) Explosive Compo­ (greater than 4 mm diameter) in simulated rain nent, given the 300 series of test numbers. In should be several times greater than that of a addition to these portions of MIL-STD-331, there typical heavy tropical rain so that a correspond­ are three additional Military Standards that ap­ ingly greater range will be simulated by a prac­ ply to fuzes. MIL-STD-320 covers terminology, tical distance of rain facility. For example, rain dimensions, and materials of explosive compo­ produced by a test facility of 1200 ft in length nents used in fuzes; MIL-STD-322 covers the should be 5 times greater in density of rain drops evaluation of electrically initiated explosive de­ in order to simulate a natural rain shower of ap­ vices that are used in fuzes; and a MIL-STD not proximately 6000 ft of depth. yet numbered covers fuze threads and contours for artillery and mortar ammunition’. All of the In both cases, the probability of impacting a pertinent MIL-STD tests that apply to fuzes are similar number of drops of equivalent size would listed in Table 15-5. be approximately the same. MIL-STD tests are not usually specified unless 15-5 MILITARY STANDARDS AND SPECIFI­ they serve a definite purpose. The selection of CATIONS tests for application in a specific case requires engineering judgment. In no case should tests be Standard tests and specifications are essential applied indiscriminately without due considera­ for efficient operation, intelligent design, and tion as to necessity and costs involved. The fuze successful mass production. They permit uni­ tests are grouped together for convenience, but form evaluation and promote interchangeability. not with the intent that all should apply to every Military Standard Tests have been established for development or production. On the other hand, all military items and the tests in MIL-STD-331 these tests are standards. Once a particular test contain the bulk of the information on fuze has been prescribed, it is mandatory that it be tests. performed precisely as specified without excep­ tion or deviation. In addition, there is for each service fuze a Military Specification that describes it fully. Occasionally during development, certain tests Typical headings of a fuze specification include are conducted on fuzes where deviations from name, purpose, description, requirements, related the MIL-STD’s are required. If this is the case, specifications, handling or safety precautions, when the test is reported, the deviations should and assembly drawings. be sufficiently described in order to permit another person to repeat this test. A series of Military Standards covering perti­ nent technical knowledge has been developed 15-6 ANALYSIS OF DATA jointly by the Army, Navy, and Air Force. Some of these Standards and Specifications list mate­ To make certain that his conclusions are valid, rials and components used in fuzes, and suggest the fuze designer employs statistical procedures. methods for testing, sampling, and packaging. Such procedures have been developed from the The Military Standards for fuzes are tests for first step of selecting a sample to the final in­ checking both safety features, and operation of ference of future performance. 15-13

AMCP 708210 TABLE 15-5. MILITARY STANDARDS FOR FUZES 1. M IL -S T D -331, F u z e and Fuze C o m p o n e n ts , E n v i r o n m e n t a l a n d Performance Tests FOF, 10 J a n u a r y 1966. Superseded MIL-STD Test No. Title Nos . Date Class 100, Laboratory Tests 101 J o l t 3 0 0 ,3 5 0 6 Ju ly 1951 102 Jum ble 3 0 1 ,3 5 1 6 Ju ly 1951 103 40-foot Drop 3 0 2 ,3 5 2 6 Ju ly 1951 104 T ransportation V ibration 303 22 Ju ly 1963 353 15 O cto b er 1963 105 T em perature H um idity 304, 6 Ju ly 1951 354 27 M arch 1952 106 Vacuum Steam Pressure 305, 26 M arch 1952 355 13 A p ril 1953 107 Salt S pray (Fog) 306, 27 M arch 1952 356 13 A p ril 1953 108 W aterproofness 314 20 S eptem ber 1954 109 Rain Test (Exposed Fuze Storage) 323 5 Ju n e 1953 110 Fungus Resistance 324 12 June 1963 111 5-foot D rop 325, 30 S eptem ber 1963 358 17 N ovem ber 1958 112 Extreme Tem perature Storage 326 7 O ctober 1963 113 327 11 O cto b er 1963 114 Therm al Shock 328 15 O ctober 1963 115 315 29 N ovem ber 1954 Rough Handling (Packaged) 201 307 17 N ovem ber 1958 202 Static Detonator Safety 308 4 A ugust 1953 Class 200, Field Tests 203 309 5 A ugust 1953 204 Jettison (Aircraft Safe Drop) (Fuzes) 1514 310 5 A ugust 1953 Jettison (Simulated Aircraft Safe Firing, From Ground Launcher) (R ocket Type) Jettison (Simulated Aircraft Safe D rop, From G round Launcher) Jettison (Aircraft Safe Firing) (Rocket Type)

AMCP 706-210 TABLE 15-5. MILITARY STANDARDS FOR FUZES (Cont'd) Superseded MIL-STD Test No. T itle Nos , Date Class 200, Field. Tests (Cont'd) 321 1 Septem ber 1959 2 0 5 Jettison (Aircraft Safe Drop) 311 4 A ugust 1953 (Fuze System s) 3 1 2 15 J a n u a r y 1954 206 A ccidental R elease (Low A ltitude, 31 3 15 J a n u a r y 1954 H ard Surface) 318 6 F ebruary 1959 207 M uzzle Im pact S afety (Projectile) 319 20 M ay 1959 329 4 N ovem ber 1963 2 0 8 Im pact Safety Distance (Projectile) 330 7 N ovem ber 1963 2 0 9 Missile Pull-off from Aircraft on 316 23 N ovem ber 1961 Arrested Landing (Ground Launcher 3 1 7 17 D ec em b e r 1959 Sim ulated) 2 1 0 Time-to-air B urst (Projectile Time) 2 1 1 Field Parachute Drop 212 Catapult and Arrested Landing C l a s s 300, Explosive Components Tests 301 Detonator O utput M easurement by Steel Dent 302 D etonator O u tp u t M easurem ent by Lead Disc 2. M I L - S T D - 3 2 0 , Terminology, D im ens ions, and Materials o f Explosive Components, For Use in Fuzes, 2 J u l y 1 9 6 2 . 3. M I L -S T D - 3 2 2 , Basic Evaluation f o r Use in Development o f Electrically Initiated Enp los ive Components for Use in Fuzes, 15 O c to b e r 1 9 6 2 . 4. MIL-STD- , Fuze Thread, Fuze Contour and Projectile Cavity Designs for Artillery and M ortar Ammunit ion. ( U n d e r p r e p a r a t i o n a t p r e s e n t - u s e A B C A - A rm y -S T D - 1 0 1 A during interim.) It is im portant th at all variables be considered sample is large, its behavior ‘u nder te st will con­ when analyzing test results. While the important form closely w ith th a t of th e o rig in a l lot. H o w ­ variables may be obvious, care m ust be taken not ever, th e sam p le size h a s p ra c tic a l lim ita tio n s to overlook an y critical p a ra m e te rs. O ften a b ased on costs of p ro cu rin g fuzes an d ru n n in g check list is helpful for this purpose. tests, particularly so because m any tests are de­ stru ctiv e so th a t ea ch fuze c a n be te s te d only F u zes are m a n u factu red in huge lots from once. which only a few are chosen to be tested. These constitute a “sample” th a t m ust be selected care­ Realizing the importance of considering all as­ fully. S tan d ard sta tistica l m ethods are available pects of evaluation, th e fuze designer is p articu ­ to m a k e s u r e t h a t s a m p l e s a r e s e le c te d “a t larly concerned w ith th e p ecu liarities arisin g ran d o m ” to re p re se n t th e lo t faith fu lly . If th e from fuze testing, with sampling procedures, and 1115

AMCP 706-210 with data analj sis. Analysis of variable data dif­ conclusions may be draw n in the same m anner. fers from that of yes-or-no data and safety analy­ sis is separated from emphasis. Since test data exhibit dispersion or scatter, nearly all m easurem ents have a deviation from The developm ent of fuzes is complicated by the average value. Thus there are at least two im­ the fact that the only com pletely reliable test is portant qualifying term s about a set of data, the proof test; i.e., testing the fuze in the m uni­ namely, the average value or arithmetic mean, tion for which it w as designed but under sim u­ and the standard deviation a defined as the root lated combat conditions. Since proof testing mean square of the deviations. The first indicates usually destroys and certainly damages the fuze, the central value of the data and the second the the causes of m alfunctions can not be reliably spread around that value. Further, when apply­ found by examination. Thus fuze criteria have ing the average sample m easurem ent to the lot to be determ ined by statistical inference. Econ­ from which the sample was chosen, the designer om y requires th a t a small sam ple be tested, b u t must speak only of a probable value of the meas­ confidence in a high reliability cannot be assured ured param eter. Then from the standard devia­ if the test sample is too small. Since the principles tion of the sample value and from the sample of statistics m ake it possible to attribute a cer­ size, this probable value is qualified by a state­ tain degree of confidence to the results obtained ment of confidence in its correctness. with a sample of given size, the designer can de­ termine what compromise between accuracy and The concepts of random sampling, frequency econom y m u st be adopted in his particular case. distributions, m easures of reliability, statistical In laboratory tests, it is possible to m easure the significance, and practical significance should all param eters of the fuze arm ing mechanism as a become part of the designer's w orking vocabu­ continuous variable. O n the other hand, it is lary so that, at the very minimum, he can recog­ possible to measure those of the fuze functioning nize those situations where a professional statis­ mechanism only for quantal response (yes or no, tician is required. The subject of experim ental fire or misfire). Even though the data from these statistics aimed specifically toward military appli­ two types of test must be treated differently, the cations is the subject of other h a n d b o o k s '. REFERENCES a-t Lettered references are listed at the end of this 7. M. C. Reynolds, R a i n M e a s u r e m e n t and S i m u l a ­ handbook. tion fo r Supersonic Eros ion Studies, Sandia Corp., Albuquerque, N.M., Feb. 1962. 1. Co mb i n e d E nv i r o n m e n t s Test ing, Journal A r ­ ticle 53.0 of the JANAF Fuze Com m ittee, 12 8. ABCA-Army-STD-lOlA, S t a n d a r d i z a t i o n of 2 ” April 1968, AD-835 813. Fuze Holes and Fuze Contours for Artillery Pro­ jectiles 75 mm and Larger in Caliber, i n cl udi ng 2. P. A. Borden and W. J. M ayo-W ells, Telemeter­ 81 mm, 4.2\" and 107 mm M o r t a r s , A m e ric a n - ing Systems, Reinhold Publishing Corporation, British-Canadian-Australian Armies Standardi­ N.Y 1959. zation Program, 5 April 1966. 3. W. H. M ermagen et a I ., VHE a n d UHF Hi g h - G 9. AMCP 706-110, En gin eerin g Design Handbook, Telemetry Instrumentation f o r H A R P Vehicles, E xper i ment al S t a t i s t i cs , Secti on 1, B a s i c C o n ­ U.S. Army Ballistic Research Laboratories, cepts and Analysis o f Measurement Data. Memorandum Report 1768, Aberdeen Proving Ground, Md., May 1966. 10. AMCP 706-111, Engineering Design Handbook, Ex p e r i me n t al S t a t i s t i c s , Secti on 2, A n a l y s i s o f 4. Edward N. Dean, Acceler omet er and Drop T e s t Enumerative and Classificatory Data. Studies and Recommendations for Revision o f MIL-STD-302, Rheem Mfg. Co., N.Y., Report 11. AMCP 706-l 12, Engineering Design Handbook, R-159-19, 30 September 1 9 5 5 . Ex p e r i m e n t al S t a t i s t i c s , Se c t i on 3, P l a n n i ng and A n a l y s i s of C o mp a r a t i v e Experiments. 5. M IL -E -5 2 7 2 B , E n v i r o n m e n t a l T e s t i n g , A e r o ­ nautical and Associated Equipment, General 12. AMCP 706-l 13, Engineering Design Handbook, Specification for, Dept. of Defense, 5 June 1957. Experimental Statistics, Section 4f S p e c i a l 6. A Rain Survey of Rain Simulation Techniques, , Journal Article 52.0 of the JANAF Fuze Com­ Topics. mittee, 3 May 1967, AD-834 086. 13. AMCP 706-l 14, Engineering Design Handbook, 15-16 Ex pe ri me nt al S t at i s t i c s , Secti on 5, Tables.

AMCP 706-210 GLOSSARY This Glossary is principally an excerpt of sodium nitrate charcoal and sulphur. It is N om enclature and D efin itio n s in the Ammuni­ easily ignited and is friction sensitive. For­ tion Area,MIL-STD-444, Change 2, 9 July 1964. merly extensively used as a propellant, but Definitions are often abbreviated and non-fuze now its military use is almost exclusively in terms are not included. propellant igniters and primers, in fuzes to give short delay, in powder train time fuzes, Actuator-An explosive device that produces gas in blank ammunition, and as spotting charges. at high pressure in short periods of time into a Boobytrap-An explosive charge usually con­ confined volume for the purpose of doing cealed and set to explode when an unsuspect­ work. Dimple motors, bellows motors, and ing person touches off its firing mechanism as switches are examples of actuators. by stepping upon, lifting, or moving a harmless looking object. Aligned-Said of an explosive train when ar­ Booster-An assembly of metal parts and explo­ ranged in such order that the detonation sive charge provided to augment the explosive wave can propagate as required for func­ components of a fuze to cause detonation of tioning. the main explosive charge of the ammunition. It may be an integral part of the fuze. (This A m m unition-A generic term for munition in­ term is often used as an abbreviation for cluding all materials thrown or used against an booster charge.) enemy. Items of ammunition are explosive or B ooster C harge- 1. The explosive charge con - pyrotechnic devices used mainly to inflict dam­ tained in a booster. It must be sufficiently age upon military objectives but also used for sensitive to be actuated by the small explosive such purposes as illuminating, signaling, de­ elements in the fuze and powerful enough to molishing, or operating mechanisms. cause detonation of the main explosive filling. 2, The amount or type of explosive used to re­ Angle of Entry-The acute angle between the liably detonate the bursting charge of ammu­ tangent to the trajectory and the perpendicu­ nition. lar to the target surface. It is the complement of the angle of impact. Also called angle of Bore Riding Pin-See Pin, Bore Riding. obliquity and angle of incidence. Bore Safety-See Fuze, Bore Safe. Angle of Im pact-The acute angle between the Brisance-The ability of an explosive to shatter tangent to the trajectory and the target plane. It is the complement of the angle of entry. the medium which confines it; the shattering effect shown by an explosive. Angle of Incidence-See Angle of Entry. Burster-A n explosive element used in chemical ammunition to open the container and disperse Angle of Obliquity- See Angle of Entry. the contents. Bursting C harge-The main explosive charge in a A ntirem oval D evice-A device attached to a land mine, bomb, projectile, or the like that breaks mine to protect it against removal. the casing and produces fragmentation or de­ molition. It is the pay load. Arm ed-The condition of a fuze normally re­ Com m itted-The condition of a fuze in which the quired to permit functioning. arming process has reached the point from which arming will continue to completion Arming-The changing from a safe condition to a even though the arming forces cease. state of readiness for functioning. Arming per­ C ook-off-The deflagration or detonation of am­ tains to safety and is one of ,the two principal munition by the absorption of heat from its actions of a fuze (the other is functioning). environment. Usually it consists of the acci­ dental and spontaneous discharge of, or ex­ Arm ing Delay-See Delay, Arm ing. plosion in, a gun or firearm caused by an overheated chamber or barrel igniting a fuze, Arming Pin or Wire-See Pin, Arming. propellant charge, or bursting charge. Arming Range-The distance from a weapon or launching point at which a fuze is expected to become armed. Also called safe arming dis­ tance. Arm ing Vane- See Vane, Arm ing. Black P ow der (BP) -A low explosive consisting of an intimate mixture of potassium nitrate or G-l '

AMCP 706210 Cord, D etonating-A flexible fabric tube contain­ primer. In the former case it is also called ini­ ing a filler of high explosive intended to be in­ tiator. It is capable of reliably initiating high itiated by a blasting cap or electric detonator. order detonation in the next high explosive component of the train. Creep-The forward motion of fuze parts rela­ D etonator Safety-A fuze is said to have a deto­ tive to the missile that is caused by decelera­ nator safety when functioning of the detonator tion of the missile during flight. Also called cannot initiate subsequent explosive train com­ creep action. ponents. D eflagration-A very rapid combustion some­ Dud-An explosive ammunition or component times accompanied by flame, sparks, or spat­ tering of burning particles. A deflagration, al­ that has failed to explode, although detona­ though classed as an explosion, generally im­ plies the burning of a substance with self- tion was intended. contained oxygen so that the reaction zone Escapem ent-A mechanical device that regulates advances into the unreacted material at less than the velocity of sound in the unreacted the rate of transmission of energy. It is nor­ material. mally used as a part of the clockwork in a Delay-An explosive train component that intro­ mechanical time fuze. duces a controlled time delay in the function­ Explosion-A chemical reaction or change of ing process. state which is effected in an exceedingly short D elay, A rm in g - 1. The interval expressed in time time with the generation of a high temperature or distance between the instant a piece of am­ and generally a large quantity of gas. An ex­ munition carrying a fuze is launched and the plosion produces a shock wave in the surround­ instant the fuze becomes armed. 2. The time ing medium. The termincludes both detona­ interval required for the arming processes to be tion and deflagration. completed in a nonlaunched piece of ammu­ Explosive-A substance or mixture of substances nition. which may be made to undergo a rapid chem­ ical change, without an outside supply of oxy­ D elay, F u n ctio n in g --T he interval expressed in gen, with the liberation of large quantities of time or distance between initiation of the fuze energy generally accompanied by the evolution and detonation of the bursting charge. of hot gases. Destructor-A cylindrical metallic item contain­ Explosive, High-See HighExplosive. ing explosive components for destruction of material by explosion. Explosive, Low-See Low Explosive. Explosive, Prim ary High-See Prim aryHigh Ex­ Detent-A releasable element used to restrain a part before or after its motion. Detents are plosive. common in arming mechanisms. Explosive Train-A train of combustible and ex­ Detonation-An exothermic chemical reaction that propagates with such rapidity that the plosive elements arranged in an order of de­ rate of advance of the reaction zone into the creasing sensitivity. Its function is to accom­ unreacted material exceeds the velocity of plish the controlled augmentation of a small sound in the unreacted material The rate of impulse into one of suitable energy to cause advance of the reaction zone is termed deto­ the main charge of the munition to function. nation velocity. When this rate of advance at­ It may consist of primer, detonator, delay, re­ tains such a value that it will continue without lay, lead and booster charge, one or more of diminution through the unreacted material, it which may be either omitted or combined. is termed the stable detonation velocity. When Fail Safe-Descriptive of fuze design features the detonation velocity is equal to or greater whereby a component failure prevents the fuze than the stable detonation velocity of the ex­ from functioning. plosive, the reaction is termed a high order Firing D evice-A mechanism design to detonate detonation. When it is lower, the reaction is the main charge of explosives contained in termed a low order detonation. boobytraps, mines, and demolition charges. There are several types of either metallic or Detonator-An explosive train component that nonmetallic construction: pressure, pull, re­ can be activated by either a nonexplosive im­ lease, or combination thereof. pulse such as a firing pin or by the action of a Firing Pin-See Pin, Firing. P-2 Functioning-The succession of normal actions from initiation of the first element to delivery

AMCP 706210 of an impulse from the last element of the ex­ tronic nature. Such a fuze does not necessarily plosive train. Functioning is one of the two have to be entirely electric but may contain principal actions of a fuze (the other one is mechanical components. arming). Fuze, E lectric Tim e-A fuze in which the time from initiation of action to functioning can be Functioning Delay-See Delay, Functioning. controlled by setting, and is determined by electronic events. Fuse-An igniting or explosive device in the form Fuze, Hydrostatic-A fuze employed with depth of a cord, consisting of a flexible fabric tube bombs or depth charges to cause underwater and a core of low or high explosive. Used in detonation at a predetermined depth. Initia­ blasting and demolition work, and in certain tion is caused by ambient fluid pressure. ammunition. Fuze, Im pact-A fuze in which the action is ini­ tiated by the force of impact. It is sometimes Fuze-A device with explosive components de­ called a contact fuze or percussion fuze. signed to initiate a train of fire or detonation Fuze, Long D elay-A type of delay fuze, espe­ in an item of ammunition by an action such as cially for bombs, in which the fuze section is hydrostatic pressure, electrical energy, chem­ delayed for a relatively long period of time, ical action, impact, mechanical time, or a com­ from minutes to days. bination of these. Types of fuzes are distin­ Fuze, M e c h an ic al T im e-A fuze which is actuated guished by modifying terms forming part of by a clocklike mechanism preset to the desired the item name. (In some cases the explosive time. components may be simulated or omitted.) Fuze, M edium D elay-A type of delay fuze, es­ pecially for bombs, in which the fuze action Fuze, A ll-w a y - An impact fuze designed to func­ is delayed normally four to fifteen seconds. tion regardless of the direction of target im­ Fute, M ild D eto n atin g -A small-diameter, con­ pact. tinuous metal tubing having a high-explosive core. The core consists of 1 to 5 grains per foot Fuze, A ntidisturbance-A fuze designed to be of PETN. It is initiated by a detonator or lead. come arm ed after impact, or after being em­ Fuze, N o nd elay-A fuze that functions as a re­ placed, so that any further movement or dis­ sult of inertia of firing pin (or primer) as the munition is re ta rd e d during penetration of tar­ turbance will result in detonation. get. The inertia causes the firing pin to strike Fuze, Bare-An unprotected and unpackaged the primer, initiating fuze action. This type of fuze is inherently slower in action (usually fuze separated from its intended piece of 250-500 nsec) than the superquick or in- ammunition. staneous fuze because its action depends upon Fuze, Base-A fuze installed in the base of a deceleration (retardation), of the munition during impact with the target. Also called iner­ projectile. tia fuze. Fuze, B asedetonating (B D )—A fuze, located on Fuze, Nose-A fuze for use in the forward end (nose) of a bomb or other munition. The term the base of a projectile, designed to be acti­ is not generally applied to fuzes for use in ar­ tillery projectiles, where the term point fuze vated as a result of impact. is more commonly used. Fuze, Bore Safe-A fuze that has a means for Fuze, Pointd eto n atin g (P D )—A fuze which is lo­ cated in the nose of a projectile and is de­ preventing the detonator from initiating an ex­ signed to be actuated as a result of impact. plosion of the bursting charge while the pro­ Fuze, P oint-initiating (PI)-A fuze which has the jectile is within its launching tube. target sensing element in the nose of the muni­ Fuze, C om m and-A fuze that functions as a result tion. The detonating portion of such a fuze is of intelligence transmitted to it from a remote usually in the base. location by means not directly associated with Fuze, P roxim ity-A fuze wherein primary initia­ its environment. tion occurs by sensing the pressure, distance, Fuze, Delay-Any impact fuze incorporating a means of delaying its action after contact with G-3 the target. Delay fuzes are classified according to the length of time of the delay. (See also Fuze, Long Delay; Fuze, Medium Delay; Fuze, S hort Delay; and F u ze, T im e .) Fuze, Dummy-An imitation of a fuze which has the same shape, weight and center of gravity as the fuze but has no explosives or moving parts. Fuze, Electric-A fuze which depends for its arm­ ing and functioning upon events o f an elec­

AMCP 706-210 and direction, or all of these of the target within the munition, the length of that portion through the characteristics of the target itself of the fuze which intrudes. or its environment. Lead-(Rhymes w ith \"feed\") A n explosive train component which consists of a column of high Fuze, Short Delay-A type of delay fuze used explosive, usually small in diam eter, used to both in bom bs and artillery projectiles, in transmit detonation from one detonating com­ w hich the fuze action is delayed for a period ponent to a succeeding high explosive compo­ of time less than one second. nent. It is generally used to transmit the deto­ nation from a detonator to a booster charge. Fuze, Superquick-A fuze designed to function with the least possible delay after impact. The Low Explosive (L E )—An explosive w h ich w h en delay is on the order of 100 /isec. used in its normal manner deflagrates or burns rather than detonates, i.e., the rate of advance Fuze, Tail-A fuze inserted in the after end of a of the reaction zone into the unreacted m ate­ bomb. rial is less than the velocity of sound in the un­ reacted material. Low explosives include pro­ Fute, Time-A fuze th at can be preset to func­ pellants, certain prim er mixtures, black pow ­ der, and delay compositions. tion after the lapse of a specified time. Fuze Cavity-A socket or hole in a bom b, p ro ­ M alfunction-Abnormal or unexpected perform ­ ance of an explosive component or a fuze. jectile, or the like for receiving a fuze, or a por­ tion of the fuze. (See also Dud.) Graze Sensitivity-The ability of a fuze to be ini­ tiated by grazing, i.e., when the missile strikes Missile-Any object th a t is, or desig n ed to be, a surface at a glancing angle (SO\"-90\" from the throw n, dropped, projected, or propelled for normal). the purpose of m aking it strike a target; for High Explosive (HE)-An explosive w hich w hen example, bombs, rockets, guided missiles, or projectiles. used in its norm al m anner detonates rather than deflagrates or burns, i.e., the rate of ad­ Out-of-line Safety-A term descriptive of a meth­ vance of the reaction zone into the unreacted od by w hich detonator safety or bore safety m aterial exceeds the velocity of sound in the is attained. In the safe condition, one or more unreacted material. com ponents of the fuze or booster explosive Igniter-A device containing a specially arran g ed train are in a nonaligned condition w ith re­ charge of a ready burning composition, usually spect to the other com ponents, so the norm al black powder, used to amplify the initiation of functioning cannot occur. a primer. Inert-Descriptive of a condition of am m unition, Pin, Arming-A safety device used in fuzes. A pin or com ponent thereof, which contains no ex­ (or wire) partly inserted into a fuze to prevent plosive, pyrotechnic, or chemical agent. The the arm ing process from starting u n til its re­ opposite condition is live. Initiation-l. As applied to an explosive item, the moval. beginning of the deflagration or detonation of Pin, Bore Riding-A safety p in w hich is h eld in the explosive. 2. The first action in a fuze which occurs as a direct result of the action of place in the fuze while the projectile or missile the functioning medium. 3. In a time fuze, the is within the gun barrel'or launching tube and starting of the action w hich is term inated in then ejected from the fuze by centrifugal ef­ the functioning of the fuzed munition. fects or spring action beyond the muzzle. Initiator-A device used as the first element of an Pin, Firing-An item in a firin g m echanism of a explosive train, such as a detonator or squib, fuze which strikes and detonates a sensitive which upon receipt of the proper mechanical explosive to initiate an explosive train. or electrical impulse produces a burning or Premature-A type of m alfunctioning in w hich detonating action. It generally contains a small am m unition functions before the expected quantity of a sensitive explosive. time or circumstance. Interrupter-A barrier in a fuze w hich prevents Prim ary High Explosive-An explosive which is transm ission of an explosive effect to some extrem ely sensitive to heat and shock and is elem ent beyond the interrupter. It is used to normally used to initiate a secondary high ex­ obtain fuze safety. plosive. A prim ary explosive is capable of Intrusion-For a fuze which is partially housed building up from a deflagration to detonation in an extremely short distance and time; it can G-4

AMCP 706-210 also p ro p ag ate a d eto n atio n w ave in an ex ­ forces are exerted on one or more of the parts trem ely small diameter column. which cause shearing of the pin or wire. Primer-A r e la tiv e ly s m a ll a n d s e n s itiv e in itia l Shelf L ife-T h e s to ra g e tim e d u r in g w h ic h a n explosive train component which on being ac­ item rem ains serviceable. tu a te d in itia te s fu n ctio n in g of th e explosive Shutter-See Interrupter. train and will not reliably initiate high explo­ Signature-The id e n tify in g c h a ra c te ris tic s p e c u ­ sive charges. In general, prim ers are classified liar to each type of target which enable fuzes in accordance w ith th e m ethods of in itiatio n ; to sense and differentiate targets. such as percussion or stab. Spin-The rotation of a munition about its longi­ Primer, P e rc u s s io n -P rim e r d e s ig n e d to b e in iti­ tu d in a l axis to provide stab ility during flight. ated by percussion, i.e., crushing th e explosive Spin S a f e - S a id o f a fu z e t h a t is s a fe w h e n e x ­ between a blunt firing pin and an anvil. Primer, S ta b -A p r im e r d e s ig n e d to b e in itia te d p e r i e n c i n g a r o t a t i o n e q u i v a l e n t to t h a t at­ by piercing it w ith a pointed firing pin. R elay-A n explosive tra in co m p o n en t th a t p ro ­ tained during flight; thus, other forces are nec­ vides the required explosive energy to reliably essary to arm th e fuze. function the next element in the train. It is es­ Squib-A s m a ll ex p lo siv e d ev ice, s im ila r in a p ­ p ecially ap p lied to sm all ch a rg es th a t a re in ­ p ea ra n c e to a d eto n ato r, b u t lo ad ed w ith low itiated by a delay element and, in turn, cause explosive, so th a t its o u tp u t is p rim a rily h e a t the functioning of a detonator. (flash). U sually electrically initiated, and pro­ Safing and Arming Device-A m e c h a n is m w h ic h vided to initiate action of pyrotechnic devices. p rev e n ts or allow s th e w arh ea d tra in of ex ­ Unarm ed-The c o n d itio n o f a fu ze (or o th e r plosives to o p erate. firing device) in which the necessary steps to Self-destruction (S D )-A te r m d e s c rip tiv e o f a n p u t in co n d itio n to fu n ctio n h av e n o t ta k e n ev en t w hich occurs from fuze action w ith o u t place. It is the condition of the fuze when it is outside stimulus, when provided for in the de­ safe for handling, storage, and transportation. sign, b y w h ich th e fuze effects m u n itio n d e ­ Vane, Arm ing-A m e ta llic ite m d e s ig n e d for a t ­ stru ctio n a fte r flig h t to a ran g e g re a te r th a n tach m en t to’ th e fuze m echanism of a bom b. th a t of th e target. The vane arm s the fuze through action of the S etback-T he relativ e re a rw a rd m ovem ent of air stream created by falling of the bomb. component parts in a munition or fuze under­ W arh ead -T h at p o rtio n of a ro ck et or guided going forward accelerations during its launch­ missile designed to contain the load which the ing. T hese m ovem ents, and th e setb ack force vehicle is to deliver. I t m ay be em p ty or con­ which causes them, are used to promote events ta in high explosives, chem icals, in stru m en ts, w hich p articip ate in th e arm ing and eventual or in e rt m a teria ls. I t m ay include booster, functioning of th e fuze. Shear Pin-A p in o r w ire p ro v id e d in a fu z e d e ­ fuze(s), and burster. sign to hold parts in a fixed relationship until W indshield-A ro u n d e d o r p o in te d h o llo w cu p ad d ed to th e nose of a p rojectile to im prove streamlining. Also called a false ogive or ballis­ tic cap. G-5

AMCP 706-210 GENERALREFERENCES It is assu m ed th a t th e rea d er h a s a g en eral e. MIL-STD-320, T erm in ology, Dimensibns and know ledge of m ilita ry am m u n itio n . F or th is Materials of Explosive Components for Use in reason, the basic elements of ammunition are not tre a te d in th is handbook. S u ch in fo rm atio n is F u z e s , July 1962. Establishes terminology, dimensions, and pre­ c o v e r e d i n R e f e r e n c e s a a n d b. T h e f u z e e x p l o ­ ferred stru c tu ra l m a teria ls for explosive com po­ nents. sive tra in , of k ey im p o rta n ce in fuze d esig n , is f. MIL-STD-322, B a sic E va lu a tio n T est f o r Use co v ered in C h a p te r 4, a n d , in g re a te r d ep th , in in Development o f Electrically Initiated Explo­ Reference c. M ilitary S tandards on fuze testing, sive Components for' Use in Fuzes, 15 October References A, e , and / , are discussed in detail in C hapter 14. The set on I n f o r m a t i o n Pertaining 1962. to Fuzes, References g to m , is a series of volumes Provides a uniform evaluation of input, output, th a t covers useful information on fuzes and fuze and environm ental response of initiated explosive developm ent, as w ell as h isto rical inform ation. elements prior to their use in military items. g. S. Odierno, lnformation Pertaining to Fuzes, V arious subjects on fuze d esign have been g rouped in a collection of J o u rn a l A rticles, Volume I, M echanical and E lectron ic Time R eference n . In d iv id u al citatio n s are listed in Fuzes (U), Picatinny A rsenal, Dover, N.J., A p p e n d i x I I . T h e f u z e c a t a l o g , R e f e r e n c e o, is a descrip tiv e listin g of all fuzes. N ote th a t R ef­ 15 August 1963, AD-355 052 (Confidential). erence j an d / co n tain a m ore recent, alth o u g h less detailed, listin g of A rm y com ponents an d C atalogs th e ch aracteristics of artillery tim e fuzes. A ll asp ec ts of p ro x im ity fu zes are d is­ fuzes. cussed in th e classified handbooks, R eferences P to t. h. S. Odierno, Information Pertaining to Fuzes, Volume II, Propelling Charges, Picatinny Arse­ N o te th a t specific referen c es u se d for th e nal, Dover,N.J., 22 November 1963, AD-451 449. material discussed in this handbook are listed at the end of each chapter. C atalogs th e ch aracteristics of propelling charges for ammunition. a. T. C. Ohart, E lem ents o f A m m u n ition , John i. S. Odierno, Information P erta in in g to Fuzes, Wiley a n d S o n s , Inc., N.Y. 1946. Volume Ill, Artillery, Armor Defeat and Mortar Fuzes; PD, BD, P IB D and Time (Pyrotechnic D iscu sses th e b asic elem en ts involved in th e T ype)(U ), Picatin ny Arsenal, Dover, N.J., 1 design and developm ent of am m unition. March 1964, AD-355 053 (Confidential). b. TM9-1900, Ammunition General, Dept, of Army, Catalogs the characteristics of fuzes for artil­ June 1956. lery and m ortar projectiles. Contains basic information and illustrations on ty p es an d iden tificatio n of am m u n itio n (u n d er j. S. Odierno, Information Pertaining to Fuzes, revision as TM 9-1300-200). Volume IV, E xplosive C om ponents, Picatinny c. AMCP 706-179, En gin eerin g Design Handbook, Arsenal, Dover, N.J., September 1964, AD-451 450. Explosive Tr ains . Catalogs the characteristics of explosive com­ C ontains the principles and factors applicable ponents used in fuzes and of die sizes for booster to the design of the various elements of explosive pellets. trains. d. MIL-STD-331, Fuze and Fuze Components, En­ k. S. Odierno, I n f ormation Pertaining to Fuzes, vironmental and Performance Tests For, lO J a n - Volume V, Fuze Safing Philosophy, Picatinny Arsenal, Dover, N .J-, April 1965, AD -456 253. uary 1966. D escribes m ethods for estab lish in g realistic Specifies the environm ental and perform ance safety and reliability goals for fuzes. •tests for use in th e development and production of fuzes and fuze components. R -l