9-lb. Illuminating Rocket Mk II (Service)

Over-all length

Maximum diameter

Weight

Height of ejection

Burning time

Candlepower

General: This rocket is currently used only by the Royal Observer Corps to indicate to patrolling fighters the presence of low-flying enemy aircraft. The rocket is firing from a Type B Rocket Projector Mk IV, using a 60-grain percussion cartridge.

Description: The rocket consists of a steel rocket tube, a tail, and a metal flare con-tainer, which houses a parachute, flare candle, and burster charge. The rocket tube is filled with a propellant composition, with a conical cavity in the center. At one end of the rocket tube is a gun-metal choke crimped in position and closed with a paper disc.

At the other end of the steel tube is a clay plug provided with flash hole. The flare container is fastened with screws to a metal junction head, which houses the burster charge and a length of quickmatch. The burster charge is held in position by a wooden washer, covered with primed cambric. Attached to the flare container is a waterproofed sleeve, which fits over the projector barrel to prevent rain from entering the barrel when the projector is loaded.

The flare candle consists of a rolled paper case, strengthened at one end by a tin-plate cap and held in place with felt packing. The strengthened end of the cap contains a fusible metal cup having a central hole. Housed in this cup are a quantity of gunpow-der, priming composition, and two igniter pellets. The gunpowder and priming composition are held in place by a muslin disc.

The main illuminating filling of the candle is pressed in position and held in place by a millboard disc. A wooden block, resting on the millboard disc, has a central hole to recei-ve one end of a wire strap, which is looped around a metal rod passing through the woo-den block. The block is riveted to the paper case. The other end of the wire strap is at-tached to a 36-in. parachuute, packed in the flare container between a wooden washer, cardboard spacers, and a wooden disc. The top of the flare container is closed by a me-tal lid secured to the container with adhesive tape.

The rocket is stabilized in flight by a tail secured to the rocket tube. The tail consists of four fins attached to a bridle, which is fitted to the rocket tube.

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 flash from the cartridge breaks the paper sealing disc, passes through the choke, and ignites the rocket propellant composition, which then forces the rocket along its trajectory. When the rocket composition is amost burned through, the flame passes through the flash hole and ignites the length of quickmatch and 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.