Bombs Used in: Photographic flash bomb parachute flare – LC 20 containers – ABB 500 M.10 (Boden).

DESCRIPTION. The length of the fuze is 2.2 inches and the head is oversized (one-half inch larger than normal). Within the fuze case is a clock mechanism similar in operation and construction to the clock used in the (17) series. The gearing has been changed to give delay times up to 80 seconds. This delay may be varied by rotating the setting but-ton. A projection on the underside of the set-ting button engages a nub on the timing disc and turns it to the desired setting.

The clock is prevented from starting by a spring loaded plunger passing through the ba-lance wheel. The plunger is held down by a lead plug seated in a rubber collar. The collar is retained by a brass disc. The lead plug is connected to the dropping gear by a 3-inch brass cable. (See fig. 178.)

OPERATION. When the bomb or flare is released from the aircraft, the lead plug holding down the arming plunger is pulled free of the rubber collar by means of the brass cable attached to the bomb rack. This action allows the spring-loaded plunger to remove itself from the balance wheel. The clockwork is now allowed to start and after running the pre-set time, it releases the striker to fire the fuze.

REMARKS. The (89) has no charging plunger and is therefore easily distinguish-able from all other (9) types. The fuze is not initiated electrically and the time delay is provided by the clock.

Figure 178 – (89) Clockwork Aerial Burst Fuze