Description
These fuzes are of the arming vane type and are used in GP bombs and M series demolition bombs from 100 to 2,000 pounds, inclusive. 500 pound and 1,000 pound SAP bombs also utilize these fuzes. .They are used for low altitude land and sea bombing. Their action on impact is as follows: M118, 4 to 5 second delay; M119, 8 to 11 second delay. The arming time is approximately 16 turns of the arming vane. This is normally accomplished in 80 to 100 feet of air travel.
The M118 and M119 Bomb Fuzes are quick arming fuzes which may be used for extremely low altitude bombing against unarmored or lightly armored targets. They contain delay elements which give a time delay of 4 to 5 seconds for the M118 Fuze and 8 to 11 seconds for the M119 Fuze to provide time for the plane to leave the effective area of the bomb blast. The delay element provides the only difference between the two models. The fuzes are intended for special tactical missions as auxiliary fuzes in bombs in which M112, M113, and M114 Tail Fuzes are used. They are similar in appearance to the M103 and AN-M103 Nose Bomb Fuzes, differing in that they do not have the reduction gear assembly in the head, nor do they have instantaneous elements. They are not detonator safe, for the explosive train is always in line whether the fuze is in the armed or unarmed position.
Functioning
The bomb is released and the arming wire is retained in the plane. The arming vane is rotated by the air stream and since it is directly connected to the arming screw it turns the screw up and out of the striker. As the arming strew turns in the striker, it moves the vane cup forward and uncovers the arming discs which are then ejected by a spring. The fuze is now armed, the striker which carries the firing pin being prevented by a shear wire from moving inward.
Upon impact, the striker is forced inward causing the shear wire to be broken and the firing pin to strike the primer. The flame from the primer ignites an igniter of red lead and silicon which in turn functions the delay of lead chromate and silicon of either 4 to 5 seconds (M118 Fuze) of 8 to 11 seconds (M119 Fuze). The flame from the delay ignites a relay charge of lead azide which detonates and sends a wave to the detonator (upper and lower) of lead azide and tetryl. The wave is then carried to a lead charge of tetryl which in turn functions the booster of tetryl, which is a part of the fuze.
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