Description
This fuze is very much like the Point Detonating Fuze Mk 29 Mod 3, with the addition of the rotor for detonator safety. It has the firing pin and crush cap in the nose, the flash channel, the interruptor device, the rotor assembly, and the magazine. The rotor contains a lead azide detonator and is held in place by two detents. The booster magazine contains 6.7 grams of black powder in a watertight vinylite cup. A vinylite cup is cemented onto the base of the fuze to prevent the holes in the metal cover from abrading the silk powder bags in the WP load as the fuze is inserted.
An aluminum disk 0.010 inch thick between the relay detonator and the rotor housing is another safety feature. It prevents pressure from an accidental detonation in the nose from getting to the rotor after leaking past the unarmed interruptor - which the gas could do.
The fuze will detonate on impact with ground, 1/2 inch wood, or 1/8 inch mild steel plate.
The Point Detonating Fuze Mk 66 was developed to give detonator safety in 5"/38 WP projectile assemblies, which do not have auxiliary detonating fuzes.
Functioning
When the projectile is ready to be fired, the setting screw for the interruptor is turned to the ON or SQ ("Super-Quick") position. Up to this time the interruptor, in the OFF position, has blocked the flash channel so that accidental crushing of the cup, setting off the detonator, could not set off the booster charge. On setback, the interruptor sits down in the flash channel; but, as creep takes over, the centrifugal force moves the interruptor into the sleeve, clearing the flash channel.
Centrifugal force also moves the detents holding the rotor out, allowing the lead counterweights in the rotor, through centrifugal force, to rotate the rotor until the stop pins rest against the edge of the holes in the housing, thus lining up the second detonator under the flash channel. The fuze is now fully armed, and, on impact, the crush cap collapses, allowing the firing pin to set off the detonator, sending the flash down the open tube, which in tum sets off the detonator in the rotor, and finally the black powder charge.
Hazardous Components
No information about hazardous components.
See Also
Nothing else to see.
Source(s)
MIL-HDBK-146, Fuze Catalog (1982)
OP 1664, Volume 1 - US Explosive Ordnance (1947)
