ROCKET USED IN

FUNCTIONING

ARMED CONDITION

FUZES USED WITH

ARMING SPEED

MAX. BODY DIAMETER

OVERALL LENGTH

GENERAL:

The Mk 100 is similar to the Navy Point Detonating Projectile Fuze, Mk 29, with the addition of the delay plunger assembly from the Army projectile fuze, M48A2. The fuze can function either super-quick (instantaneous action), with a .05 second delay ac-cording to the setting of the key on the ogive. This fuze can only be used in spin-sta-bilized rockets as the fuze is armed by rotation or centrifugal force.

DESCRIPTION:

The fuze consists of four principal parts: the base which houses the Army delay plunger assembly, the nose or detonator assembly which contains the striker and deto-nator Mk 25 Mod 0 for super-quick action, the plastic ogive, and the flash tube which is fitted in the center of the ogive and holds the nose and base together.

In the nose, the striker is held in position by a gliding metal cap which collapses on impact and permits the striker to fire the detonator. The setting device consists of a plunger or interrupter, a spring and a selector sleeve. The hole in the selector sleeve is off center, and the setting of this sleeve determines whether the interruptor is aligned with the hole or whether the wide shoulder of the sleeve engages the plunger. If the selector sleeve is set on "SQ", the interruptor is free to move outward under centrifugal force to compress the spring and thereby open the flash tube for super-quick or instan-taneous action. If the sleeve is set for delay, the wide shoulder engages the interruptor to prevent it from moving outward by centrifugal force. In this instance, the interruptor will block the flash tube and the delay plunger assembly operates to detonate the roc-ket head. The delay plunger assembly includes a firing pin, primer, black powder delay pellet, and a relay pellet.

OPERATION:

The fuze is designed to arm at 1500 to 2000 r.p.m. When set for superquick action (SQ), centrifugal force causes the interruptor to move outward against the spring and thereby open the flash tube. At the same time the two plunger pins locking the delay assembly in the unarmed position also move under centrifugal force. These plunger pins are prevented from returning to the unarmed position by the plunger-pin lock which swings on its pivot to place an arm against the inner end of each. Upon impact, the firing pin crushes the gliding metal cap and is driven against the detonator to initiate the super-quick action. Inertia causes the delay plunger to move forward, driving the primer against the delay action firing pin and initiating the delay action. In normal func-tioning, the delay action will have no effect as the super-quick train will have caused the shell to explode; however, if the super-quick action should fail, the delay action would function to prevent the rocket from being a dud.

When fuze set for delay action (D), the interruptor would block the flash tube and nullify the effect of the super-quick train. The delay plunger assembly would operate to detonate the rocket.