Nose Fuze No. 32 Mks II* and III (Obsolescent)

Description: This fuze consists of a two-piece body, the upper part of which is alu-minum, and the lower brass. The lower body is cylindrical, while the upper body is slop-ing. Through the upper body extends the vane hub and arming vanes, and on the sides are attachments for the safety pillar and the safety wire. On the lower body is found the delay ring with the markings ZERO, 0.5, 1.0, 1.5, 2.0, and BRIDGE. The delay-setting spindle is covered by the setting-ring cap.

Within the upper body is housed in the gear system, consisting of a movable and sta-tionary gear. The former is attached to the end of the arming spindle and has 60 theeth, while the latter is fixed to a bearing in the fuze body and has 69 theeth. Armound these move a rotatable pinion and counterweight. To the lower end of the arming spindle is theaded the arming nut, into which is fitted the upper end of the striker. The arming nut is prevented from rotating by a guide screw, moving in a longitudinal slot in the arming nut. In the unarmed condition the striker rests in a hole in the spring-loaded shutter, preventing it from moving into the armed position. When the gear system has moved the arming nut up and removed the striker from the detonator shutter, the shutter is forced over by its spring and locked in place by a spring-loaded plunger.

Located to one side of the arming nut is an igniferous detonator, held off a needle striker by a creep spring. This detonator is carried in an inertia pellet, which contains a flash channel. The pellet is prevented from moving against the creep spring until after the arming nut is raised on the spindle. At the lower end of the flash channel in the iner-tia pellet are two chamber-closing plugs, one of which contains loose gunpowder. The plug containing this powder has radial holes extending from the powder cavity to an an-nular groove on the outside of the plug. A flash channel from the annular groove extends through the fuze body to a space between the delay ring and the tensioning ring. A hole housing the ignition pellet extends from the tensioning ring to the delay ring, which con-tains the circular groove holding the delay train. A flash-hole pellet and two connecting-hole pellets join the end of the delay train to the firing hole. The firing hole leads into a detonator located in the detonator shutter. Below this is a C.E. stemmed channel which leads into the magazine with its C.E. pellet. Around the threaded lower body of the fuze is a securing ring, above which a rubber ring is located to afford a watertight seal in the bomb.

Operation: When the bomb is fuzed and loaded aboard the plane, the safety pillar is removed. The safety clip with the stop pin is pulled free when the bomb is released. The vanes rotate and turn the pinion gear and counterweight around the movable and statio-nary gears. For each sixty rotations of the vanes, the movable gear is rotated once. This action threads the arming nut upwards on the arming spindle, thus removing the striker from its hole in the shutter. The detonator shutter spring lines up the detonator with the striker and the stemmed channel. The shutter is locked in this position by a spring-loaded plunger. The fuze is now armed.

The delay mechanism is in operative condition as soon as the arming nut has been threaded up the arming spindle. The inertia pellet is then free to move forward and force the igniferous detonator against the striker.

The fuze functions either instantaneously on impact or after a set delay. If it strikers steel plate which is 3/8-in. or thicker, the sides of the upper body will crush and force the striker down into the detonator. If the fuze hits the water when dropped from 500 to 4000 feet, or hits a target not sufficiently hard to crush the upper body, the igniferous detonator and the inertia pellet move forward, compressing the creep spring and hitting the needle striker. The flash travel down the channel in the inertia pellet and ignites the loose gunpowder. The flash from the gunpowder passes through the flash channel, firing the ignition pellet and the delay train. When the latter has burned out, the flash-hole pellet and the connecting-hole pellets are fired and send a flash down through the firing hole to the detonator. The magazine pellet is then fired, initiating the explosion of the bomb.

Figure 149 - Nose Fuze No. 30