Tail Fuze No. 844 Mk I (Obsolescent)

Description: The fuze consists of a cylindrical, flanged body, which is externally threaded to permit the fuze to be screwed into the after end of a smoke float. A seating washer beneath the flange ensures a watertight joint between the fuze and the smoake float.

A cover fits over the body and is held in position by a U-shaped securing wire which passes through an annular groove in the body and two holes in the cover. The wire does not prevent rotation of the cover, which can be turned for the purpose of adjustment. A base plug is screwed into the body and supports a detonator holder, which is in turn screwed into it. The detonator holder houses a detonator and a gunpowder pellet.

One end of the striker is screwed into a striker head. A creep spring, which engages the striker head and the base plug, holds the striker clear of the detonator. A hole ex-tending through the striker head is aligned with two holes in opposite sides of the cover. A safety pillar is screwed into one of the holes in the cover and projects into one end of the hole in the striker head. A safety rod passes through the other hole in the cover and extends into the opposite end of the hole in the striker head. The safety rod is retained in position by a pull-off spring, which is locked between a fork-ended swivel block and a shoulder on the safety rod. A pin passing through the forked end of the swivel block pro-vides an anchorage for a fuze setting control link.

A wipcord becket, extending around the fuze, passes through the forked end of the swivel block and a hole in the safety pillar.

Operation: The fuze is screwed into the tail end of a smoke float, and the fuzed smoke float is loaded into the carrier. The swivel block is connected in the fuzing unit by a fuze-setting control link. Just before the airplane takes off, the safety pillar is remo-ved.

When the smoke float is released from the carrier, the swivel rod, safety block, and pull-off spring remain attached to the carrier by the fuze-setting control link, so that the striker is held away from the detonator only by the creep spring while the smoke float is falling.

On ground or water impact, the striker moves down, overcoming the creep spring, to pierce the detonator. The detonator fires the gunpowder pellet, and the flash from the gunpowder pellet fires the igniter of the smoke float.

Figure 155 - Tail Fuze No. 844 Mk I