Smoke 500-lb. Mk II (Service)

Body Construction: The bomb consists of a cylindrical bomb body made of thin sheet steel, with a nose plate welded to one end of the body. Three catch brackets, spaced 120° apart, are welded to the nose plate, and a nose fairing is secured to the catch brackets by spring clips. Immediately beneath the nose plate is located a loading plate. An exploder pocket is welded to the nose plate and contains an ejection charge. A nose plug is secured into the exploder pocket.

An igniter tube with four series of perforations extends down the center axis of the bomb and contains a celluloid tube holding a primed cambric tube. The igniter tube is held in place by the igniter-tube holder, located in the center of the tail plate. The remainder of the bomb body is filled with three banks of smoke generators, each bank consisting of eight wedge-shaped units fitted with drag plates.

A tail plate, to which is welded the fuze adapter, is secured to the inside of the after end of the bomb body by six brass rivets. A tail locating ring is fitted to the inside of the tail plate.

Tail-Construction: The Tail No. 81 Mk I consists of a cylindrical strut held in place on the truncated tail cone by four sheet metal fins. The tail is held in place on the bomb by the usual four spring clips, which engage in four similar recesses in the tail ring on the bomb body. A locating pin in the tail ring engages a slot in the bottom edge of the tail cone to position the tail.

Functioning: When the bomb is released from the aircraft, the fuze is armed. At a predetermined height, the fuze functions and the flash from the fuze magazine ignites the contents of the igniter tube. The perforations in the igniter tube allow the bursting celluloid and primed cambric to initiate the smoke generators and eventually the ejection charge. The pressure of the gases generated by the ignition of the ejection charge bears against the loading plate and forces the whole inner assembly against the tail plate, which shears the six brass rivets holding it to the bomb casing. The tail plate and atta-ched tail unit are then thrown clear of the bomb, and the bomb contents are ejected through the tail.

Suspension: This bomb is equipped for suspension in either British or American air-craft, having a single suspension lug on one side and dual lugs 180° removed.

Remarks: Should water, especially sea water, come into contact with the smoke composition used in this bomb, the smoke composition is liable to spontaneous due to chemical action.

Figure 50 - Smoke 500-lb. Bomb Mk II