Position and method of fixing in bomb: The fuze is screwed into the nose of the bomb. A steel locking ball prevents removal.

Components of explosive train: A standard Japanese Navy gaine is screwed into the base of the fuze.

Fuzes likely to be found with: C-1 (a) Navy chemical long dealy tail fuze.

Delay times: Up to 125 hours.

Threads: 61/64 inches in diameter, 12 threads per inch.

Description: The fuze consists of a steel body in which are housed the arming assembly and the delay assembly. The arming assembly, which is housed in the upper end of the body, consists of the arming vanes which are attached to the arming vane boss by three small screws. The arming vane boss is internally threaded at the lower end to receive a short, hollow arming spindle and an arming piece which is held in the base of the spindle by a copper shear wire. A small locating screw inserted in the spindle engages in the keyway of the fuze body and prevents the spindle from rotating but permits upward or downward movement. The boss is retained in the fuze body by two pins which permit it to rotate. A safety pin engages in the fuze body and the boss. The delay assembly, which is housed toward the lower end of the body, is actuated by a spring after the de-lay period has expired. Screwed into the top of the striker assembly is a steel plug with a cutaway striker assembly stem on which a brass cocking piece rides. In one side of this cocking piece is a small brass spring-loaded detent; on the opposite side is an assembly screw. The cocking piece and striker assembly stem are held in position by a copper shear wire. Under the steel plug is a soluble celluloid ring outside of which is a copper disc and a steel ball set into a drilled hole. The ball prevents the downward movement of the striker assembly as the ball rests on a shoulder of the fuze body. A lead foil disc is fitted over a copper container which is filled with acetone. A solid lead ball with a small copper stud on its side is placed in the container.

Operation: When the bomb is released, the safety pin is withdrawn allowing the arming vanes and boss to rotate. This action screws the arming spindle and the arming piece into the arming vane boss clear of the cocking piece. On impact, the cocking piece shears the shear wire and moves forward, compressing the striker spring. It is locked in the forward position by the detent, thus holding the striker unit under spring compres-sion. Simultaneously the solid ball in the acetone container breaks the lead foil disc, al-lowing the solvent to escape into the space above and dissolve the celluloid ring has be-come softened, the steel ball, due to the pressure of the striker spring, is forced away from the shoulder of the fuze body. The striker assembly, under compression of the spring is forced downward and the firing pin hits the detonator.

Remarks: If dropped from a sufficient altitude the fuze may be armed despite the pre-sence of the safety pin. If the vanes fail to rotate, the inertia of the cocking piece may be great enough to shear the shear wire and to dirve the arming piece into the provided recess in the spindle and thus permit the fuze to arm.

Antiwithdrawal: A steel ball in a groove in the threads of the fuze locks the fuze when an attempt is made to withdraw it.

Figure 132 – C-2 (a) Bomb Fuze.