The 3 kg Practice Smoke and Flash Bomb is designed for
use in practising those delivery techniques adopted for
1000 lb retarded bombs. The
bomb is released from a No 122 ERU and produces
white smoke and a flash on impact.
Safety during flight carriage and immediately after
release will not be degraded should the bomb be fired
initiated inadvertently as no significant debris, which
may damage an aircraft, will be ejected.
The body comprises a cylindrical moulded tube with
four external integrally moulded stabilising fins. The
body also houses the smoke and flash unit.
The nose is a solid steel plug, the forward end being
cupped internally to assist in the retardation of the
bomb on impact. A frangible nose cap is attached to the
cupped end of the nose. The rear face of the steel nose is
machined to receive a fixed striker.
Ground safety is achieved by a steel pin fitted between
the striker, and the smoke and flash unit. The pin is
secured by a screw threaded into the steel nose. Prior to
flight, the safety pin is removed and a three-legged
spring, fitted to the striker, restrains movement of the
smoke and flash unit.
The smoke and flash unit consists of a light alloy tube
containing pyrotechnic composition, a primer tube
containing gunpowder, and a percussion capped
cartridge.
On impact the frangible nose cap shatters. The cupped
steel nose retards downward movement of the bomb,
and inertia, acting on the smoke and flash unit,
overcomes the three-legged spring and drives a
percussion cap onto the striker. The consequent flash
fires the boost charge, which in turn ignites the primer
charge, which ignites the main pyrotechnic filling.