Description
The VT Fuze Mk 171, four times as sensitive as the Mk 172, was designed for plane-to-plane firing; but, because of poor results in this technique of firing, few of these fuzes were produced.
Functioning
When the rocket is launched, the arming wire is withdrawn from the vane locking pin, which in turn is forced out by its spring to free the vanes. At the same time, the setback produced by the sudden acceleration forces the hinged inertia weight back against its spring. The hinged inertia weight forces the locking dog from the arming stem gear sector by means of its lever linkage, freeing the gear train. The vanes rotate, driving the electric generator and the gear train. After approximately 100 vane revolutions, the gear sector on the arming stem has rotated 25 degrees clockwise to move clear of the gear train. As the gear sector clears the gear train, the tension spring snaps it 75 degrees clockwise, where it is detained by the stop pin on the hinged inertia weight. Since the arming stem and detonator rotor are integral with the gear sector, they also move 25 degrees by vane rotation and 75 degrees by spring action. The vanes continue to rotate, driving the generator and the gear train, which is disconnected from the arming stem. As acceleration ceases at the end of burning of the motor, the spring forces the hinged inertia weight forward, pulling the stop pin and freeing the gear secor. The tension gear snaps the gear sector 90 degrees clockwise into the armed position, lining up the detonator with the booster lead-in and making electrical connection to the firing circuit. The detonator is locked in position by a spring-loaded detent in the detonator rotor. When the electric detonator is connected to the firing circuit, the firing condenser is charged. After 0.7 to 1.4 seconds, the condenser has stored up sufficient power and the fuze is armed. On approach to a target, the VT element activates the firing circuit, which discharges the condenser through the electric detonator which initiates the explosive train.
Hazardous Components
No information about hazardous components.
See Also
Source(s)
OP 1664, Volume 1 - US Explosive Ordnance (1947)
