Proximity, M517 (T178E3)
Proximity Fuze M517 is used with 81mm Mortar HE Cartridge M362 series against surface targets.
The fuze contains a radio continuous wave transmitter and receiver with antennas in the plastic head and an electrical power source in the steel body as the primary detonation initiator. A safety and arming mechanism is housed in a metal cup in the base. Electrical arming is by setback force activation of the power supply. Mechanical arming is by setback displacement of setback leaves to release a spring-driven rotor with detonator. The rotor holds the detonator out of line in the unarmed condition, The fuze is fitted to the projectile with a wavy spring washer to assure a tight joint and a good electrical ground to the projectile. In addition to the proximity element, the fuze contains a PD element; however, no time setting option is provided.