T705 and T74 Series (Athwarpship Electrical Contact)

Missiles

Functioning

Arming data

T705 can be set 4 to 45 miles
T74E1 - 4 to 5 miles
T74E2 - 12 to 15 miles
T74E3 - 25 to 30 miles
T74E4 - 40 to 50 miles

General: These are the electric fuzes for the JB-2 or "Loon" missile. The T74 was re-placed by the T705, but both designs are no longer on order. The fuzes are similar, but the T705 allows variable setting of arming distances; the T74 series has a set distance for each modification. Both fuzes have the electric leads in a rubber cable running into the fuze and down to the rotor housing. The gear train is the same as that the T715 and T84 series. The rotor housing and rotor are made of plastic to provide insulation between the contacts.

Operation: These fuzes arm like the Athwartship Mechanical Impact Fuzes T715 and T84, except that, when engaged, the arming shaft turns only the rotor, and has to turn it only a quarter of a turn to bring the contact points on to the ends of the firing-circuit leads, completing the circuit. This action does not fire the fuze, however. Firing occurs when either the Nose Switch T8 or the Inertia Switch T9 in the missile is activated on impact. The Fuzes T705 and T74 merely act as safety devices - breaks in the circuit to be closed by air-travel arming.

When the rotor comes into position, completing the circuit and lining up its flash hole over the detonator in the detonator-holder disc, a detent in the rotor snaps into a hole in the rotor housing, locking it in place.

Figure 405. Athwartship Electric Fuze T705