Cluster Projectiles No. 7Cluster Projectile No. 15
U.S.N.B.D. - BRITISH BOMBS AND FUZES; PYROTECHNICS; DETONATORS
CLUSTER PROJECTILES

 

 

 

 

 

BRITISH BOMB

FUZING

Nose Fuze No. 42, Mk IV

CLUSTER PROJ.

COLOR

Dull red overall; one of

 

tensioning strap painted

 

bright red.

CONTENTS

106 4 lb. incendiaries

No. 14, Mk. I

TAIL NO.

No. 42, Mk I

 

OVERALL LENGTH

67"

(Service)

MAX. BODY DIAMETER

14"

 

TAIL LENGTH

21"

 

TAIL DIAMETER

14"

 

TOTAL WEIGHT

450 lbs.

 

 

   

DESCRIPTION:

The cluster comprises two faggots of 53 bombs each. The bombs in the two faggots are arranged nose to tail and with their safety plungers inwards so that they are all de-pressed. The bombs are held in place by a front end plate and a rear end plate, a top beam and a bottom beam, four wooden slats, tensioning straps, and a retaining bar having lateral pins which engage tabs on the tensioning straps. A shear wire passes through a bridge and the retaining bar at a position near the rear end plate. A channel, secured to the rear end plate, supports a fuze adapter, the outer end of which is clo-sed by a transit plug fitted with a leather washer. Inside the adapter is a piston through which is a pin arranged to engage the lower end of a pivoted lever. The fuze adapter and the piston are slotetd to receive the lever. The upper end of the lever is forked and is connected 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 rear end plate to re-ceive one end of a tail tie rod when the tail unit is fitted to the cluster. A nose cover is fitted to the front end plate to decrease the drag of the cluster.

TAIL UNIT:

The tail is a shortened drum type tail having a tail cone to which a tail ring is secu-red 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. The tail unit is fitted with a bearing for an arming spindle, so that if it should ever be required to fuze the cluster with an air armed fuze, a suit-able arming spindle with an arming vane could be readily fitted. Also, against this cont-ingency, a bracket to receive a safety wire is welded to the tail cone and a hole passes through a projection on the support for the arming spindle bearings. A tie rod passes through the center of the tail and one end of the rod is screw threaded to go into the central nut of the rear end plate. Two windows, one of which is open, are provided in the tail cone. The open window is provided so that when the cluster is prepared for use the fuzing link connected to the pull percussion mechanism of the No. 42, Mk IV fuze can be passed through it and be connected to the fuzing unit of the bomb carrier.

SUSPENSION:

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

FUNCTIONING:

When a cluster is released from an aircraft, the fuze is functioned and after a period of delay, during which the cluster projectile falls freely, the fuze magazine charge is fired, and 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 cluster. This causes the retaining bar to break its shear wire and to be moved so that the pins on the bar disengage the tabs on the tensioning straps. The straps then fly outwards and the cluster disintegrates, the component parts falling away separately. The individual 4 lb. bombs function on im-pact.

REMARKS:

(1) This cluster may contain explosive incendiaries mixed with ordinary incendiaries; or an entire cluster of explosive incendiaries may be carried to make up a mixed load in a given aircraft.

Cluster Projectiles No. 7Cluster Projectile No. 15