(Osaka Army Arsenal, July 1943)

Material of construction: Striker, spring, screws, stop studs, trigger, and three spacers made of steel. All other parts made of brass.

Position and method of fixing in bomb: Screwed into tail fuze pocket.

Components of explosive train: Primer and standard Army type gaine.

Fuze likely to be found with: C-3 (a).

Delay times: No delay.

Threads: 1 13/16 inches in diameter, 8 threads per inch.

Description: The vanes, similar to those of the B-1 (a) are locked to the arming spindle by a set-screw. The arming spindle, housed in the conical shaped upper fuze body, is a round shaft threaded at the top with right-hand threads to attach to the vanes and at the bottom with finer left-hand threads to fit into the inertia block.

The spacing ring screws into the upper fuze body and is secured by screws to the lower fuze body. It serves to hold the inertia block part way down against the spring. The lo-wer fuze body houses the firing mechanism and the primer cap. The trigger and the trig-ger spring are mounted on top of the lower fuze body. The trigger is pivoted on a screw threaded into the top of the lower fuze body. One end bears against the trigger spring; the other in the cocked position fits on the striker notch, preventing the spring loaded striker from firing. The trigger is prevented from pivoting by the inertia block against which it rests.

Operation: On release from the plane, the vanes rotate the arming spindle clockwise, unscrewing it from the inertia block, which is keyed to prevent rotation. The fuze is now armed. The flange of the arming spindle prevents the spindle and vanes from falling away.

On impact, the inertia block moves down against the spring and is held below the surface of the lower fuze body by the spring loaded detent. The spring loaded trigger arm is re-leased and pivots out beyond the fuze body a distance of 1/64-inch where it encounters the wall of the fuze pocket. This movement of 1/64-inch is not sufficient to release the striker. The fuze will not fire as long as it remains in the bomb. If withdrawal is attemp-ted, the trigger arm will snap into the annular groove as the last thread of the fuze poc-ket is disengaged. This movement of the trigger releases the spring loaded striker and it hits the primer.

Figure 112 – E-1 (a) Bomb Fuze.