OVERALL LENGTH

TOTAL WEIGHT

DIAMETER OF HEAD

LENGTH OF HEAD

WEIGHT OF HEAD

WALL THICKNESS

MOTOR LENGTH

MOTOR DIAMETER

RANGE

FUZES: Mk 5-0 and Mk 6-0

Mk 6-1 (only)

Base Fuze Mk 164-0

ROCKET HEAD:

The rocket heads used are the 5.0", Mk 6 Mods 0 and 1. The Mk 6 Mod 0 is filled with TNT and is equipped with a base fuze and a nose plug. When thus used, the head will have the penetration and fragmentation characteristics at comparable velocities of the 5"/38 AA Common projectile, of which it is a modified design. All 5.0" rocket heads Mk 6 Mod 0 and 1 are shipped with a base fuze installed and staked in place. No at-tempt shall be made to remove the base fuze from the head prior to the firing. A metal cup-shaped thread protector protects the external threads on the base of the head and on the base fuze. The Mk 6 Mod 1 is similar to the Mk 6 Mod 0 with a gas seal ad-ded to the bomb fuze seat. The 5.0" body Mk 5 Mod 0 is the initial CIT production which was adopted by BuOrd as the Mk 6 Mod 0. The two bodies are identical.

ROCKET MOTOR:

The 5.0" Rocket Motor Mk 2 Mod 0 consists of a seamless steel tube with internal threads on both ends. Into the rear end is screwed the nozzle plate having 8 nozzles arranged in a circle, and a central blow-out nozzle. The central nozzle is closed by a disc of 0.024" thick copper, insulated against the heat of the motor by asbestos and hard fiber plugs. The thickness of the disc is such that it shears and blows out at a pressure of approximately 2400 lbs. per square inch, which is the normal maximum motor pressure when the propellant grain is at a temperature of 100° F. If the pressure rises above this, the disc and plugs are ejected; this increases the usable temperature range of the rocket by about 40° F.

Seven of the eight nozzles are sealed individually by a light steel cup and sealing compound. The eight nozzle accommodates the electric connector cable which is crim-ped into the steel nozzle closure. In shipment, a dome-shaped steel shipping cap fits into the sleeve of the fin assembly, acting as an auxiliary seal and at the same time serving to enclose and protect the electrical pig-tail in shipment.

Lugs for attaching the fins are mounted on the nozzle end of the motor. The fins are shipped with the motor and are attached when the round is assembled. The fins are held in place by spring-loaded latches within the fin itself. The fin lugs and rear suspen-sion lugs are welded to the bands of the fin assembly, whitch is slipped on over the nozzle end of the motor. The front lug band is strapped to the motor. The motor is shipped with lug attachments on the motor tube for use with aircraft launcher Mk 5 Mod 1. An extra rail type lug is provided in the shipping box to adapt the rocket for use on the aircraft launcher Mk 4.

The front end of the motor is sealed by a steel diaphragm equipped with a blow-out disc in the center to allow easy passage of the motor gases to the pressure arming fuze in the base of the body. In shipment, a cylindrical metal thread protector extends into the motor the same depth as the body and seats on a felt rim glued to the dia-phragm seal.

The propellant is a grain of cruciform shaped ballistite weighing 24 lbs. The grain is inhibited on the outer web surface and is supported by a spacer and steel grid at the nozzle end. The propellant is ignited by a metal case igniter containing 35 grams of black powder.

The 5.0" Mk 2 Mod 1 motor was never produced. The Mk 2 Mod 2 differs in that the tail fins are welded to a sleeve which slips over the base of the tube and is clamped in place. The fin assembly is complete and separate from the motor. The rear suspension lug for use with the Mk 5 Mod 1 launcher is on an independent band. The Mk 2 Mod 3, which will supercede the Mk 0 and 2, is similar to the Mod 2 except the nozzle ring is of slightly different construction.

The 5.0" Mk 1 Mod 0 rocket motor (CIT Production) is the prototype of the Mk 2 Mod 0 (BuOrd issue). The two motors vary only in that the suspension lugs on the for-mer are welded directly to the rocket motor.

REMARKS:

1. Using fuze Mk 159 Mod 0, this rocket will penetrate 3.75 ft. of reinforced con-crete at normal incidence. At an angle of 30° obliquity, it should penetrate 2.75 ft. Fired from a plane traveling at 300 knots, fuzed with the Mk 149 Mod 0 fuze, serious damage will be caused to armor up to 1-5/8" in thickness. Using the Mk 159 Mod 0 fuze and a steel nose plug, this rocket will penetrate armor 1.0" thick before detonation.