Bomb Arming-Delay Mechanism

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... 

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... 

If the fuze has been set for "delay action" (usually 0.1 sec), the detonator is aligned with the delay expl components. Impact fires the delay primer. The flash from the primer sets off the BkPdr delay element which burns thru and sets off, respectively, the relay, the detonator, the booster lead-in, the booster and the main charge of the bomb. More detailed description of the AN-M103A1 fuze, especially of its arming mechanism is given in Ref 51a, pp 4-1 to 4-6... 

When the fuze is unarmed the expl train is broken. The delay arming mechanism provides maximum safety for dive bombing as well as protection against detonation when the bomb is accidentally released from an aircraft flying at low altitude... 

The expl components of each of the above fuzes consist of a delay element, a detonator, a booster lead, and a booster chge (1.9-oz of Tetryl). Its safety features consist of a safety (cotter) pin, which passes thru holes in the flange of the vane-cup and in the flange of the vane-cup support and locks the reduction mechanism to prevent the fuze from arming. The arming wire keeps the fuze unarmed until it is withdrawn when the bomb is released. These fuzes are "detonator-safe and "shear-safe"... 

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