6¼-lb. Illuminating Rocket No. 1 Mk I (Service)

Over-all length

Maximum diameter

Total weight

Height of ejection

Burning time

Candlepower

General: This rocket is currently used by the Royal Observer Corps to indicate the presence of low-flying enemy aircraft to patrolling fighters, and by the Air/Sea Rescue Service to assist in sea rescue searches at night. The rocket is fired from a Type B Rocket Projector, Mk III or IV, using a 60-grain percussion cartridge.

Description: The rocket consists of a rocket tube, a sliding tail, and a flare container, which houses a burster charge, flare candle, and parachute. The rocket tube is filled with a rocket-propellant composition, having a conical cavity in the center, and is closed at one end by a gun-metal choke crimped in position. The choke is closed by a paper seal. At the other end of the rocket tube are a wooden block and a clay plug, with a hole to receive a length of quickmatch. The flare container is crimped to a metal junction head secured by screws to the wooden block. Housed in the junction head are a wooden washer, covered with primed cambric, and the burster charge, which is held in place by another wooden washer.

The flare candle consists of a rolled paper case, strengthened at one end by a tin-plate cup, and held in place by felt packing. The strengthened end of the case contains a fusible metal cup having a central hole. This cup houses a quantity of priming compo-sition, which is held in place by a primed cambric disc and a paper washer. The main illu-minating composition of the candle is held in place by a millboard disc. A suspension cup, riveted to the paper case, carries a piece of wire wrapped at both ends with adhesive tape. One end of a wire strap is looped around the middle of the wire. The other end of the wire strap is attached to a 36-in. parachute, which is packed into the flare container between a wooden washer, millboard spacers, and a wooden disc. The top of the flare container is closed by a metal lid secured in place with adhesive tape.

The sliding tail is of the drum type. When the rocket is fired, the tail slides along the rocket tube until arrested by the metal choke. A leaf spring attached to one of the tail fins then holds the tail in the extended position.

The flare container is painted aluminum over-all, with filling and manufacturing infor-mation stencilled on the container in black letters.

Operation: When the projector, loaded with rocket and cartridge, is fired, the explo-sion of the cartridge breaks the paper seal on the rocket choke, and the flash passes through the choke to ignite the rocket-propellant composition. The gases generated by the burning propellant the carry the rocket along its trajectory. When the rocket compo-sition is almost burned through, it ignites the quickmatch and the primed cambric, which in turn fires the burster charge. The flash from the burster charge ignites the flare candle and forces the lid from the flare container, ejecting the ignited candle and its attached parachute.