ALLIED BOMBS AND FUZES

DESIGNATION

PRINCIPAL MARKING

(A) D.A. No. 8 Mark I

(A) D.A. No. 8

(B) D.A. No. 9 Mark I

Mark I

CLASSIFICATION

Mechanical Nose Impact

(B) D.A. No. 9

TYPE OF MISSILE

H.E. Bombs

Mark I

MARKINGS AND

BOMBS USED IN:

SUBSIDIARY

(A) 112 lb. Mark IV or VII

MARKINGS:

520 lb. R.A.F. Mark I

550 lb. R.A.F. Mark I

(B) 112 lb. Mark V

520 lb. R.L. Mark I

550 lb. R.L. Mark I

DATA

(A)

(B)

1

COLOR

Brass

Brass

2

OVERALL LENGTH
((less booster)

4.9 inches

6.1 inches

3

OVERALL WIDTH

Body - 2.0 inches
Vanes - 6.0 inches

Body - 2.0 inches
Vanes - 6.0 inches

4

MATERIAL OF CONSTRUCTION

Body brass, plunger steel, safety pin brass, and shea- ring pin 5/32 inch brass.

Body, safety pin and shear wire made of brass. Plunger is made of steel.

5

DESCRIPTION

These fuzes consist of a brass body (F) with standard parallel nose threads, the lower portion being threaded to screw into an exploder. The D.A. No. 9 Mark I fuze has the Admiralty taper nose threads instead of the parallel threads. There are two spanner flats cut on the upper portion of the body. There is a stop pin on the upper surface to prevent the arming vane assembly from jamming against the body. The plunger (B), made of steel, has a pressure plate (D) screwed perma-nently onto the threaded portion of the outer end. The arming vane assembly (C) consists of two blades rivetted to a dome, and a suspension hook (A) - not in use at present - also attached to the dome. The whole assembly is screwed into the outer end of plunger (B).

Safety Devices: - The safety pin (E) is made of brass and passes through the dome and plunger. The shearing wire (G) is a 5/32 inch brass wire which passes through the body and plunger. When the arming vane assembly (C) is in position, the pressure plate (D) is prevented from being driven in by the dome or nose piece. There are two indentations on the inner periphery of the arming vane dome which engage against a stop on the upper surface of the body (F) and prevent the dome from jamming against the body. The arming vanes are prevented from rotating by means of a stop in the bomb rack within the plane.

6

POSITION AND METHOD OF FIXING IN BOMB

Screwed into the end of the exploder tube or adapter at the nose of bomb, using a spanner wrench on flats.

7

FUZE LIKELY TO BE FOUND WITH

Tail: No. 5B Mark I or II

Tail: No. 5B Mark I or II

8

COMPONENTS OF EXPLOSIVE TRAIN

Cartridge type with cap. Can be fitted with either instan- taneous or short delay com- ponents.

Cartridge type with cap. Screwed on bottom of fuze.

9

ARMING TIME

10

OPERATION

The safety pin is removed after the bomb is placed in the dropping gear, and when the bomb is released from the plane the arming vanes are completly unscrewed by the action of the air, thus arming the fuze. When the bomb strikes the ground, the pressure plate (D) forces the plunger (B) inwards, shearing the shear wire (G). This action brings the striker in contact with the cap in the cartridge head of the detonator.