Bomb Arming-Wire Assemblies

Fig 5-19 BOMB ARMING-WIRE ASSEMBLIES (Various Types)... 

Bomb arming-delay mechanism 4 D1021 Bomb armin-vane assemblies 4 D1020 Bomb arming-wire assemblies 4 D1019 Bomb auxiliary boosters 4 D1012 Bomb blast 2 B222... 

Bomb Complete Round. It consists of all the components necessary to drop and function the bomb. The usual components are body with filler(con-stituting the payload), fin(orparachute) assembly (to stabilize the bomb in flight), fuze or fuzes(to function the bomb at the proper moment) and arming wire assembly. These components are usually assembled in the field just before the bomb is hoisted into the bomb bay of the aircraft, except in the case of small fragmentation bombs Refs l)Ohart(1946),7 216 2)Glossary of Ord... 

When the fuzed bomb is dropped, the arming wire is retained in the bomb rack in order to free the arming vane assembly, thus causing it to rotate in the airstream. After traveling thru the air at a predetermined distance, the arming of delay mechanism is completed and further rotation unscrews the arming mechanism from the fuze... 

When the fuzed bomb is released free to arm, the vane carrier is unlocked from the striker flange by withdrawal of the arming wire. The vane carrier then rotates by action of the airstream on the arming-vane assembly, driving the reduction gears which arm the fuze. Completion of 175 revolutions of the arming-vane assembly (which requires ca 1000-ft of air travel along the trajectory) arm the fuze fully. 

When a fire bomb assembled with this igniter is dropped, the arming wire is pulled and the fuze arms after about 100-ft of air travel. On impact the fuze ignites and explodes burster chge and the rest is the same as described under igniter M15 (Ref 51a, p 5-24)... 

All bombs, except the very largest, are packed in wooden boxes or crates. The fin assemblies for the larger bombs are also crated when packed separately from the bombs. Some bombs are packed with fuzes inserted but with primer-detonators removed. However, rhe fuzes are usually removed and packed in sealed moisture-proof containers. In the latter case the fuze wells in the bombs must be closed with plugs. Some fuzes are packed in the same containers with the bombs, others separately. Bombs and components are stored as shipped. Complete rounds should not be assembled in advance of requirements and assembled rounds should be carried with sealing wires and safety in place at all times until installation in the plane. The arming wire should remain in place until the bomb is released, or until the safety pins and sealing wire are replaced and secured... 

A head assembly (2) containing an arming pin (14) and a slide bar (13) is screwed into the open end of the case. A booster cup containing a booster (8) is assembled to the end of the case that contains the delay mixture. A safety wire (1), which is removed when the bomb is clustered, holds the arming pin in the fuze... 

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