SHELL, H.E.

OVERALL LENGTH

DIAMETER

TOTAL WEIGHT

FUZING

FILLING

FILLING WEIGHT

MOTOR, ROCKET, 3", N0. 7 Mk I

OVERALL LENGTH

DIAMETER

WIDTH OF FINS

TOTAL WEIGHT

PROPELLANT

PROPELLANT WEIGHT

BURNING TIME

0.5 secs. at 60° F.

GENERAL:

This rocket is designed as a heavy offensive weapon for infantry use against lightly reinforced obstacles. Only small fins are provided on the rocket motor; so stabilization in flight has been achieved by incorporating spiral rails in the interior of the launcher body. The rocket is fired from a small portable launcher by means of a light dry cell bat-tery, a. U.S. Army 10 cap exploder, or a U.S. Navy "Magnavox" firing key.

DESCRIPTION:

Shell, H.E., 21 lb., No. 5 Mk I: This shell consists of a steel cylinder closed at the forward end by a flat steel nose plug. The after end is externally threaded and reduced in diameter to screw into the shell ring of the rocket motor. A steel spigot is threaded into the after end of the shell body and contains the cordite-filled auxiliary charge con-tainer. Separated from the axuiliary cordite charge by a thin steel plate is a small deto-nator and a gunpowder pellet. Beneath this pellet the No. 297 Mk I base percussion fuze is threaded directly into the shell body. A single C.E. (tetryl) exploder pellet is lo-cated beneath the fuze in a cardboard exploder container.

Shell, H.E., 60 lb., No. 6 Mk I: The 60 lb. Shell contains a No. 297 fuze and an auxi-liary charge container almost identical to that incorporated in the 21 lb. Shell. A sligthly different spigot arrangement is employed, however, the spigot itself being externally threaded for attachment to the shell ring of the rocket motor. The nose portion of the shell is ogival and threads into the cylindrical shell body portion.

Motor, Rocket, 3", No. 7 Mk I: The motor consists of a steel tube fitted with a shell ring at one end and at the other with a venturi tube. The threaded shell ring is held in position by eight locking pins engaged by a circular band spring. The venturi is welded to the inside of the motor body. A steel grid, separated from the venturi tube by the tail obturator, supports the cog-shaped cordite propellant grain. A metal closing disc in the venturi tube supports the igniter leads, which terminate in two-pronged plug. The after end of the venturi is sealed by a cardboard closing disc. The igniter leads extend from the plug through the central annulus of the propellant grain to the metal igniter housing, which contains a small electric squib surrounded by a charge of gunpowder. Behind the metal closing disc in the venturi is located a bag of silica gel as a moisure-proofing measure. The four fins are assembled to the motor by engaging their hooks in the fin slots in the after end of the motor body and pressing home the locking catches on the fins. An extension cable 10 yards long is provided with each motor for firing pur-poses, allowing personnel to take cover when firing occurs. The extension is plugged at one end and contains a two hole socket at the other for attachment to the plug con-nected to the igniter leads of the motor.

The motor must not be fired outside the temperature range of -5° to 135° F.

REMARKS:

(1) The Shells are painted buff overall, with a 1/2" red band painted around the nose and 1" light green band painted around the body. On this latter band are stencilled in black the letters of the explosive filling. Two thin white bands are painted around the body on either side of the light green band.