ALLIED BOMBS AND FUZES

DESIGNATION

PRINCIPAL MARKING

(A) No. 5B Mark I

(A) No. 5B

(B) No. 5B Mark II

Mark I

(C) No. 23 Mark I/A/

(B) No. 5B

CLASSIFICATION

Mechanical Tail Impact

Mark II

TYPE OF MISSILE

(A) & (B) - Aircraft H.E. Bombs.

(C) No. 23

(C) - Smoke-float, Aircraft, Navigation

Mark I/A/

Mark I

MARKINGS AND

BOMBS USED IN:

SUBSIDIARY

(A) & (B) - All. H.E. bombs except 20 lb.

MARKINGS:

Mark I, all G.P. Mark I and S.N. Mark II

bombs.

(C) - Smoke float, Aircraft Navigation

Mark I

OPERATION

The safety pin (F) is removed from the fuze when the bomb is placed in the carrier. The striker pellet (G) during flight is locked in position by the arming vane nut (D). When the bomb is released from the plane, the arming vane nut (D) is unscrewed by the action of the air on the arming vanes, and the striker is free to move. When the bomb hits the ground, the striker moves forward by its own momentum, compressing the striker spring, and allowing the striker to hit the cap in the detonator.

DATA

(A)

(B)

(C)

1

COLOR

Brass

Brass

Aluminum

2

OVERALL LENGTH
(less booster)

3.9 inches.

4.0 inches.

3.7 inches.

3

OVERALL WIDTH

Body – 1.1 inches
Vanes – 4.6 inches

Body – 0.8 inch
Vanes – 3.5 inches

4

MATERIAL OF CONSTRUCTION

Brass body, steel striker coppered over to prevent rusting; copper safety pin.

Aluminum body.

5

DESCRIPTION

These fuzes consist of a body (H) threaded externally with a 1.1 inch standard thread which has two spanner flats formed above the threads. The lower end of the body is threa-ded externally for the exploder. This fuze has a steel striker pel-let (G), coppered over to prevent rusting, with three grooves formed in it which act as air release passages when the striker is moved. A fourth and deeper groove is formed longitudinally on the striker body in which a grub screw (J) engages, preventing the striker pellet from rotating. The arming vanes (C) consist of two blades soldered to the arming vane nut (D). The outer end of this nut is covered with an arming vane cap (A) made of light pressed brass which is removed before the fuze is used. The arming vane nut stop (E) prevents the arming vane assemb-ly from jamming against the body.

Safety Devices:– The safety pin (F) is mode of copper and has an instructional tag attached. The striker pellet spring (L) is a light coil spring with the inner end fitting into a hole in the striker. During flight, the arming vanes (C) are prevented from rotating by a stop on the bomb carrier. The red ring (B) on the striker pellet (G) indicates that the fuze is not armed.

6

POSITION AND METHOD OF FIXING IN BOMB

Screwed into exploder tube at tail of bomb using spanner wrench on flats.

Screwed into float of tail by lower threads.

7

FUZES LIKELY TO BE FOUND WITH

Nose: D.A. No. 8 Mark I, D.A. No. 19 Mark I or II, D.A. No. 9 Mark I and D.A. No. 20 Mark I, II or III.

None.

8

COMPONENTS OF EXPLOSIVE TRAIN

Can be fitted with either instantaneous or short delay components.

Detonator in turn fires powder train.

9

ARMING TIME

REMARKS

1. The No. 5B Mark II is identical to the tail fuze No. 5B Mark I except for the transit spring, horseshoe in shape and double (E) which is interposed the outer end of the body and the arming vane nut. This secures the arming vane against lose during transit.

2. The No. 23 Mark I/A/ is similar in construction to Fuze, Bomb, Tail, No. 5B Mark II, the same type of transit spring and striker pellet being used. It differs from the No. 5B Tail Fuze in the following respects: (a) The body is of aluminum; (b) There is no body thread and the pistol is screwed into the float by the lower thread to which the exploder or relay is attached on the No. 5B Tail Fuze; and (c) The two arming vanes are each secured to the arming vane cup by two screws.