SHELLS

H.E.

OVERALL LENGTH

DIAMETER

TOTAL WEIGHT

FUZES USED

FILLING

FILLING WEIGHT

SMOKE TRACE

OVERALL DIAMETER

DIAMETER

TOTAL WEIGHT

FUZES USED

FILLING

FILLING WEIGHT

TAIL PROPELLING, U-2", MKS I - III & VII

OVERALL LENGTH

DIAMETER

WIDTH OF FINS

TOTAL WEIGHT

PROPELLANT

PROPELLANT WEIGHT

BURNING TIME

0.9 secs. at 60° F.

GENERAL:

This rocket is designed for shipboard use against aircraft in close range attack. Be-cause of the possible danger to adjacent craft resulting from spent rounds, the H.E. shell is fitted with a self-destroying fuze. The components of the complete round in-clude a fuzed Shell H.E. 2", Mks I or II; a Shell Smoke Trace 2", Mk I; and a Tail Propel-ling, 2", Mks I-III and VII, complete with fin assembly.

DESCRIPTION:

Shell H.E. 2", Mks I & II: This shell is a normal H.E. type, internally threaded at the nose to receive the fuze, and threaded externally at the base to screw into the shell ring of the rocket motor. The Mk I shell, having 12 external threads per inch, will fit only the Mk I motor. The Mk II shell is machined with 14 threads per inch and will fit all other motors. The shell is painted buff overall, with a 1/2" red band painted around the nose portion of the shell and a 1/2" green band painted around the body. The initials of the filling are stencilled in black on the green band.

Shell Smoke Trace 2", Mk I: This shell consists of an H.E. Mk II shell body, modified by drilling and tapping the base of the shell. A nose plug is threaded into the foreward end of the shell and is centrally drilled to allow smoke emission. The drilled hole is clo-sed by a thin metal disc and a cotton cambric disc. Separated from the nose plug by two millboard washers are upper and lower perforated tubes surrounded by primed cam-bric. The smoke filling is loaded around these tubes in two increments. Beneath the lower perforated tube is located a metal container filled with 7 grains of G.20 gunpow-der. The after end of the shell is closed by a threaded thermal septum of accurately machined thickness, in the center of which are pressed 2½ grains of LDNR. The shell is painted light green overall, with two 1/2" red bands painted around the body. Heat from the rocket motor initiates the LDNR, firing the gunpowder charge and primed cambric, which initiates the smoke composition. The gunpowder explosion also blows the discs out of the nose plug of the shell.

Tail Propelling, U-2", Mks I-III & VII: The motor consists of a welded steel cylinder, in the head of which a threaded shell ring is attached by means of spring-locked pins which engage corresponding holes in the motor body. A venturi tube is welded in the after end of the motor body. The tubular cordite grain is castellated at the foreward end and rests in the motor body supported by a metal grid at the after end. The pro-pellant is initiated by an electirc igniter placed in the castellations at the foreward end. (The Mk VII differs from the other motors in that the castellations are omitted and a cylindrical metal cased ignited is employed.) The tail orifice is sealed by a cardboard, plastic, or metal closing disc, and a silica gel bag is included as a moisture-proofing measure.

Electric leads from the igniter pass through the central channel of the cordite grain to the four brass contacts on the tail. These contacts, two positive and two negative, are so arranged that proper contact is maintained with the knife edge of the projector regardless of the angle at which the round is located.

Rounds must not be fired outside of the temperature range of 0-120° F., unless filled with flashless cordite, which may be fired at temperatures between -5° and 130° F.

The motor is generally painted white or green overall, with identification markings stencilled on the outside.

REMARKS:

(1) Proposed new nomenclature for the motors is as follows: "Motor, Rocket, 2", No. 1 Mks I-III & VII".