ALLIED BOMBS AND FUZES

DESIGNATION

PRINCIPAL MARKING

(A) No. 21 Mark I or II

(A) No. 21

(B) No. 22 Mark I or II

Mark I or II

CLASSIFICATION

Mechanical Tail Impact

(B) No. 22

TYPE OF MISSILE

H.E. Aircraft Bombs

Mark I or II

MARKINGS AND

BOMBS USED IN:

SUBSIDIARY

(A) 50 lb. G.P. Mark I and 120 lb. G.P.

MARKINGS:

Mark I.

(B) 250 lb. G.P. Mark I and 500 lb. G.P.

Mark I.

DATA

No. 21 Mark I or II

No. 22 Mark I or II

1

COLOR

Brass

Brass

2

OVERALL LENGTH

4.0 inches.

4.0 inches.

3

OVERALL WIDTH

Body - 1.1 inches
Vanes - 3.25 inches

Body - 1.1 inches
Vanes - 5.15 inches

4

MATERIAL OF CONSTRUCTION

Brass body, steel striker, and copper safety pin.

5

These fuze consist of a brass body (K) with 1.1 inch standard thread. There are two spanner flats on the body above the threads, and the lower end is threaded to screw into the exploder. The steel striker pellet (E), coppered over to prevent rust-ing, has three grooves formed in it which allow air to escape into the body when the striker moves forward. A fourth groove, formed longitudinally on striker pellet, into which a grub screw (J) is engaged, prevents the striker pellet from rotating. The arming vane assembly consists of a nut (B) to which are soldered four vanes. The arming vane cap (A) is made of light pressed brass, and is placed over the arm-ing vane nut which is removed before the fuze is used.

Safety Devices:– Transit spring (C), horseshoe in shape, fits between the fuze body and the arming vane nut, securing the arming vanes during transit. This spring is removed before the fuze is placed in the bomb. The arming vanes are kept from rotating during transit in the plane by a stop in the bomb carrier. The safety pin (D) is replaced by the fuzing wire afting the bomb is placed in the carrier. The striker pellet spring (G) or creep spring, fits between the body of the striker and the de-tonator, keeping it in position except when impact occurs. A red ring (H) can be seen when fuze is not in armed position.

6

POSITION AND METHOD OF FIXING IN BOMB

Screwed into exploder tube at tail of bomb, using span- ner wrench on flats.

Screwed into tail adapter, using spanner wrench on flats.

7

FUZES LIKELY TO BE FOUND WITH

Nose: D.A. No. 19 Mark I or II.

8

COMPONENTS OF EXPLOSIVE TRAIN

May be fitted with either instantaneous or short delay com-ponents.

9

ARMING TIME

10

OPERATION

When the bomb is released from the carrier, the fuzing wire is withdrawn and the arming vanes are freed. After the vanes have unscrewed completely, the fuze is armed. On impact, the striker moves forward from its own inertia force, compress-ing the striker pellet spring and in turn striking the cap in cartridge head of the detonator.

11

REMARKS

1. Pistol (Fuze) Aircraft Bomb, Tail, No. 21 Mark I, is a conversion of old stocks of Pistol Aircraft Bomb, Tail, No. 5B, Mark I. Difference occur in the number of blades of the arming vanes and their diameter.

2. Pistol (Fuze) Aircraft Bomb, Tail, No. 21 Mark II, is of new manufacture and is identical in all respects with the Mark I Pistol.

3. Pistol Aircraft Bomb, Tail, No. 22 Mark II, is of new manufacture and is identical in all respect with the Mark I Pistol.