Caliber: 78 mm.
Over-all length: 28.5 inches.
Weight (complete round): 15 pounds 3 ounces.
Filling: Flaked TNT.

Dimensions:

Length: 8 inches.
Diameter: 3 inches.

Dimensions:

Length: 12.8 inches.
Diameter (outside): 3.07 inches.
Diameter (inside): 2.75 inches.
Weight: 4 pounds, 5.25 ounces.

Dimensions:

Length: 7.48 inches.
Outside length of fins: 5.31 inches.
Rear diameter across fins: 7.87 inches.

External.
Internal: 3.34 inches.

Weight: 2 pounds, 0.25 ounces.

Inlet:

Maximum diameter: 2.48 inches.
Minimum diameter: 0.782 inch.
Length: 0.92 inch.

Throat: Diameter: 0.782 inch.

Outlet:

Minimum diameter: 0.782 inch.
Maximum diameter: 1.653 inch.

Grid:

Diameter: 2.72 inches.
Thickness: 0.51 inch.
Weight: 3 ounces.

DESCRIPTION. This is a fin-stabilized projectile with an appearance typical of small cali-ber aircraft rockets. The internal arrangement of the projectile suggests that it was pos-sibly copied or adapted from a standard Russian aircraft rocket. Although this rocket al-most certainly was designed primiarly as an aircraft weapon, it was also fired from a mul-tiple-frame ground launcher known as the 8-cm Raketen Vielfachwerfer. The projectile consists basically of an H.E. warhead, a rocket motor, and a tail unit incorporating a single venturi and stabilizing fins.

Warhead. The warhead of the projectile is a steel cylinder with an ogival nose into which is built a fuze system. The rear of the head is closed by an adapter plug which also forms the junction with the rocket motor.

The main H.E. filling consists of a pressed flake TNT and is built up from three perforated pellets which fit around the exploder tube incorporated in the fuzing system. At the nose end is a small cardboard washer; at the base are two wax-ed-paper washers; and around the exploder magazine is a waxed-cardboard tube. Between the shell wall and the explosive is a thin layer of bituminous material. The outer surfaces of the pellets are waxed.

Rocket Motor. The body of the motor is formed by a cylinder which is machined down slightly between the ends. The forward end of the cylinder is threaded internally to screw over the adapter ring plug which forms the junction with the warhead. Four studs in the body, two at each end, guide the projectile in the launcher. The base of the motor body is closed by the motor closing plate, which is in the form of a single venturi to which four stabilizing fins are spot welded.

The propellant consists of six sticks, of which two are slightly shorter than the other four. The four longer sticks are located by a supporting grid which is a push fit in the venturi assembly. The other two sticks are supported on the two primary igniters atta-ched internally to the walls of the rocket motor.

The ignition system consists of two ignition charges, one at each end of the propellant, and a primary igniter. The primary igniter is in the form of two copper tubes, each screw-ed internally over the end of the steel guiding studs which pass through the motor body at the rear end. A brass rod, insulated by a rubber sleeve, passes through the guiding stud and bears against a brass contact inside the copper tube. This contact passes through the tube into a small cardboard container holding a loose composition charge of gunpowder. Wires from the contact to the walls of the copper tube serve to ignite the charge. The circuit is presumably formed by two leads, one to the brass rod in each guiding stud, and is grounded to the rocket body.

Fuzing System. This rocket has a fuze which has been designed specifically for it. The ar-rangement of the system is shown in figure 206. The fuze consists of a steel nose piece which contains a light alloy striker supported by a light creep spring. Below the nose pie-ce is a steel magazine tube, into the forward end of which is screwed the detonator housing. Directly below the magazine tube is the arming mechanism which consists of a metal sleeve containing a spring loaded screw and the plunger. Holding the spring loaded screw and the plunger in position is a fusible metal ring. When assembled, the plunger fits into the lower end of the magazine and the booster pellets rest on it.

When in position a shown in figure 206 the detonator is beyond the reach of the striker and the fuze is unarmed. When the rocket is fired, the heat of the burning propellant is conducted through the wall of the spigot, and melts the fusible metal ring. The plunger, magazine, and detonator are then free to move forward under the action of the spring. The extent of this forward movement depends upon the acceleration of the rocket. Ap-proximate measurements indicate that if this is less than 40-50 g the detonator is suf-ficiently forward to be fired by the striker.

Figure 206 – 8-cm Aircraft Rocket