GENERAL:

This is an aircraft rocket weapon designed pri-marily for use against submarines and merchant shipping, atlhough more recently wide use of the rocket has been made against land targets of an unarmored or lightly armored nature. The complete round consits of a 3" aircraft rocket motor and one of the four following heads; Shell, H.E., 60 lb. F., No. 1 Mk I; Shell, H.E. 60 lb. S.A.P., No. 2 Mk I; Shot, 25 lb., S.A.P., Mk I; and Shot, 25 lb. A.P., Mk I. In addtion, two concrete practice heads are also used, one weighing 25 lbs., the other 60 lbs.

60 lb. F Shell

Shell 60 lb. S.A.P.

Shot 25 lb. A.P. & S.A.P.

OVERALL LENGTH

DIAMETER

TOTAL WEIGHT

FUZING

FILLING

FILLING WEIGHT

3 lbs. 14 oz.

12 lbs.

DESCRIPTION:

Shell, H.E., 60 lb. F., No. 1 Mk I: This shell has been manufactured by modifying a 4.5 inch Howitzer shell. The nose of the shell is recessed and internally threaded to re-ceive the nose fuze, while the base portion carries a threaded spigot for attachment to the shell ring of the rocket motor. The shell is painted dark green overall, with the marking "F. 60 lb. No. 1 Mk I" stencilled in 1/2" yellow letters around the shell body.

Shell, H.E., 60 lb. S.A.P., No. 2 Mk I: This shell consists of a cylindrical steel body internally threaded to receive a heavy steel ogival nose cap. The after portion of the body is internally threaded to receive a spigot, by which the shell is attached to the shell ring of the rocket motor. In the spigot is carried a gunpowder thermal initiator and a base fuze, beneath which is located a C.E. (tetryl) booster pellet. The shell is painted dark green overall with a 1/2" white and a 1/2" red band near the nose. A 1" light green band is painted around the shell body, and on this band are stencilled the initials of the explosive main filling.

Shot, 25 lb. S.A.P., Mk I: This is a solid steel shot, the nose portion of which is ogi-val, the after portion terminating in a threaded spigot of reduced diameter, which screws into the shell ring of the rocket motor. The shot is painted black overall, except for the nose end, which is painted white for a distance of 1 inch.

Shot, 25 lb. A.P., Mk I: Externally this shot appears identical to the S.A.P. shot. The nose portion is ogival, and the after body consists of a threaded spigot of reduced dia-meter, which screws into the shell ring of the motor. The spigot, in the case of the A.P. shell, is a separate component, screwing into the internally threaded base portion of the shell. The spigot is held in place by a locking pin or a set-screw, which pierces the spigot and engages with the shell body. The shot is painted black overall, but carries a 1/2" white band in addition to the 1" white dip on the nose.

Shell, 60 lb. Practice (Concrete) Mk I: This is a blunt nosed cylindrical head consist-ing of an adpater, externally threaded to screw into the shell ring of the motor and fit-ted with eight steel reinforcing rods, welded into place. The concrete is then formed around the reinforcing rods and shaped to measure 20 inches overall and 6 inches in diameter.

Shell, 25 lb., Practice (Concrete) Mk I: This shell is manufactured in an identical manner to the 60 lb. Practice Shell, but measures only 11.5" in lenght by 5" in diameter.

OVERALL LENGTH

DIAMETER

WIDTH OF FINS

TOTAL WEIGHT

BURNING TIME

PROPELLANT

PROPELLANT WEIGHT

DESCRIPTION:

Motor, Rocket, A/C, 3", No. 1 Mk I: This motor consists of a long caylindrical steel cylinder with a shell ring at the forward end held in place by eight locking pins, which are held in engagement by two circular band springs. A thin metal head obturator is lo-cated beneath the shell ring and is separated by cardboard washers from the forward end of the propellant grain. The head of the grain is castellated to accommodate the igniter Fuze, Electric, No. 53*. The base of the propellant grain is supported by a metal grid, which in turn rests against the tail obturator. The steel venturi tube is welded to the inside of the motor just behind the tail obturator and contains a bag of silica gel as a moisture-proofing measure.

The igniter leads extend from the igniter through the central annulus of the tubular cordite grain (along the outside groove of the cruciform grain in the No. 1 Mks II & III motors), through the venturi and tail obturator, and end in a two-pronged plug. This plug connects with a socket extension on the rail launcher when the rocket is loaded aboard the plane.

Eight slots are located in the motor body near the after end for attachment of the four fins. The rockets are suspended by two saddles, each carrying a T-lug, which rides in the grooves of the launcher rails. A "Duplex" saddle arrangement has been devised whereby two rockets may be suspended one above the other and fired simulaneously as a single unit.

REMAKRS:

(1) Motor, Rocket, A/C, 3" No. 1 Mk II: Motor differs from the No. 1 Mk I in that the propellant grain is cruciform in shape rather than tubular. The igniter leads are brought along the outside grooves of the grain, rather than through a central annulus, and a different type grid is employed. Proposed new nomenlcature for the No. 1 Mk II motor is "Motor, Rocket, A/C, 3", No. 5 Mk I."

(2) Motor, Rocket, A/C, 3" No. 1 Mk III: Motor differs from the No. 1 Mk II in that a single pronged plug terminates the igniter leads instead of a double plug.

(3) Motor, Rocket, A/C, 3" No. 1 Mk IV: This motor differs from the No. 1 Mk III only in that a small metal clip is loosely inserted over the igniter leads between the Niphon plug and the attachment to the metal closing disc.

(4) These motors are colored either green or white overall, with identification sten-cillings in yellow.