FUZING

COLOR

CONTENTS

OVERALL LENGTH

WIDTH ACROSS FLATS

TOTAL WEIGHT

TAIL LENGTH

TAIL WIDTH ACROSS

FLATS

TAIL NO.

DESCRIPTION:

The cluster is hexagonal in cross section and comprises ninety 4 lb. smoke bombs, arranged in five faggots of eighteen. The bombs are arranged nose to tail longitudinally, and in alternate rows the bomb fuzes point in opposite directions. The bomb are held in place by a front end plate and a rear end plate, a top beam and a bottom beam, four side plates, tensioning straps, and a retaining bar. Lateral pins on the retaining bar en-gage tabs forming part of shoes attached to the ends of the tensioning straps. The four side plates, together with the two beams, completely surround the bomb cluster. A channel secured to the rear end plate supports a fuze adapter, the outer end of which is closed by a transit plug and leather washer. Inside the adapter is a piston through which is a pin to engages the lower end of a pivoted lever. The fuze adapter and piston are slotted to receive the lever, which is connected at its upper end to the retaining bar.

The rear end plate has two dowels for locating the tail in position, and a nut welded to the center of the plate receives one end of a tail tie rod when the tail unit is fitted to the cluster. The front end plate has two dowels for locating a nose cover in position, and a securing bolt is screwed into the center of the end plate to receive a fixing nut when the nose cover is fitted to the cluster.

TAIL UNIT:

The tail unit consists of a taile cone with an approximately hexagonal base, and a tail ring secured to the cone by fins. At the base of the tail cone are two holes to fit over the dowels on the rear end plate of the cluster. A tie rod passes through the cen-ter of the tail, and one end of this rod is threaded to screw into the central nut on the rear end plate. The other end of the rod is fitted with a tensioning nut for securing the tail to the cluster. The tail unit also has an arming spindle mounted in bearings and having a fork at its inner end and an arming vane at its outer end. The safety wire, when fitted, passes through holes in a bracket, a projection on the support for the arming spindle bearings, and a blade of the arming vane. Two inspection windows in the tail cone are provided to enable the armorer to watch the fork of the arming spindle when fitting the tail unit.

SUSPENSION:

A British type suspension lug is fitted to the top beam of the cluster and tapped holes are provided for fitting American type lugs.

FUNCTIONING:

When a cluster projectile fuzed with a No. 867 fuze is released, the safety wire is withdrawn from the tail unit arming vane and the shear wire of the fuze is broken to re-lease the fuze safety pin. After a period of delay during which the cluster projectiles falls freely, the fuze magazine is fired. The products of combustion of the magazine charge force the piston in the fuze adapter against the lower end of the pivoted lever, which is thus rocked about its pivot and exerts a pull on the retaining bar of the clus-ter. The pull breaks the shear wire passing through the retaining bar, and moves the bar so that its pin disengage the tabs on the shoes attached to the tensioning straps. The straps then fly outwards and the cluster disintegrates, its componet parts falling away separately. The individual bombs function on impact.

REMARKS:

If the smoke composition used in the 4 lb. smoke bombs gets wet, and especially if wetted by sea water, it is liable to spontaneous combustion through chemical action.