German Explosive Ordnance - Rockets (Part 14)

German Explosives

8-cm Raketen Sprenggranate (H.E. Aircraft Rocket)

Caliber: 78 millimeters

Overall Length: 28.5 inches

Weight (complete round): 15 pounds 3 ounces

Filling: Flaked TNT

Warhead Material: Steel

Rocket Motor Material: Steel

Warhead Length: 8 inches

Warhead Diameter: 3 inches

Rocket Motor Length: 12.8 inches

Rocket Motor (outside): 3.07 inches

Rocket Motor Diameter (inside): 2.75 inches

Rocket Motor Weight: 4 pounds 5.25 ounces

Venturi Material: Steel

Venturi Length: 7.48 inches

Outside length of fins: 5.31 inches

Rear diameter across fins: 

-External: 7.87 inches

-Internal: 3.34

Venturi Weight: 2 pounds 0.25 ounces

Inlet Maximum Diameter: 2.48 inches

Inlet Minimum Diameter: 0.782 inches

Inlet Length: 0.92 inches

Throat Diameter: 0.782 inches

Outlet Maximum Diameter: 1.653 inches

Outlet Minimum Diameter: 0.782 inches

Grid Diameter: 2.72 inches

Grid Thickness: 0.51 inches

Grid Weight: 3 ounces

Propellant: Double base powder in mono perforated stick form.

Description: This is a fin-stabilized projectile with an appearance typical of small caliber aircraft rockets.  The internal arrangement of the projectile suggests that it was possible copied or adapted from a standard Russian aircraft rocket.  Although this rocket almost certainly was designed primarily as an aircraft weapon, it was also fired from a multiple-frame ground launcher known as the 8-cm Raketen Vieflachwerfer.  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 waxed-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 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 attached 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 screwed 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 fuze consists of a steel nose piece which contains a light alloy striker supported by a light creep spring.  Below the nose piece 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 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.  Approximate measurements indicate that if this is less than 40-50 grams the detonator is sufficiently forward to be fired by the striker.

8.6-cm H.E. Rocket (Spin Stabilized)

Nature of Projectile: Multiple base-venting, spin-stabilized pusher rocket.

Caliber: 8.6 centimeters

Overall Length: 16.25 inches

Overall weight: 17 pounds 15 ounces pounds

Nature of filling: H.E.

Nature of the fuze: Base

Warhead Length: 9.55 inches

Warhead Diameter: 3.35 inches

Type of Filling: Cast TNT

Rocket Motor Length: 6.7 inches

Length of Propellant Chamber: 6.08 inches

External Diameter: 3.18 inches

Internal Diameter: 2.94 inches

Weight of Filled Motor: 6 pounds 12.25 ounces

Propellant Length: 5.9 inches

Diameter of Propellant: 2.78 inches

Weight of Propellant: 2 pounds 7.75 ounces

Analysis:

-Potassium Nitrate: 75.5 percent

-Carbon: 15.35 percent

-Sulphur: 9.15 percent

-Volatile Material: 0.86 percent

Description: This rocket consists of a H.E. head, a motor, and a venturi assembly.  An integral base fuze, centrifugally armed and pressure fired, is located int he base of the H.E. head.

The H.E. head threads over the rocket motor housing, which contains a single, multi-perforated, propellant grain.  A venturi assembly, with eight jets drilled in it, is threaded to the base of the motor.  A single threaded hole in the center of the venturi assembly contains a percussion primer.  On the forward end of the motor housing is a fitting which receives one of three interchangeable delay trains.  The rockets bear markings to indicate which of the delay trains have been assembled.  Those marked "/400/" and "/800/" contain, in addition to the delay train, a fuze with a striker retained by four arming balls and a spring collar.  A light anti-creep spring is placed between striker and the detonator.

Centrifugal force causes the balls to move outward against the collar and arm the fuze.  The delay train is initiated by the propellant grain, and when the delay expires, the pressure developed forces the striker against its spring and into the detonator.  Impact with some resistant object before the expiration of the delay will force the striker into the cap.  In the case of the round marked "/600/" no striker mechanism is included, and the delay initiates the detonator and booster directly, giving only self-destroying action.

Remarks: This is a naval round, designated "8.6 cm R. Spr. 400 Wsm. (600 Wsm, 800 Wsm)."

The H.E. head is painted canary yellow overall; the motor body, dark green.

It is estimated that this projectile would reach a maximum height of 8,000 feet, if fired at a quadrant elevation of 90 degrees.

Next Time: Rockets (Part 15)

Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters

German Explosive Ordnance - Rockets (Part 13)

German Explosives

7.3-cm Propagandagranate 41

Weight (w/o Leaflets): 7 pounds 3 ounces

Length Overall: 16.1 inches

Weight of the Propellant: 1 pound 1 ounce

Weight of Propellant Unit: 3 pounds

Maximum Diameter: 2.85 inches

Description: The projectile consists of two steel tubes, screwed into a central joint.  The lower tube contains the rocket motor and the upper tube serves as a container for the leaflets.  The projectile is spin stabilized and is fired from the Propagandawerfer, which is a single launching tube.

The rocket motor is formed by the lower tube and a screwed-on base plug.  The base plug has 12 venturi set in 2 rings; those in the inner ring are straight and those in the outer ring are offset.  A copper percussion cap is located centrally in the base of the plug.

The propellant consists of a cylindrical stick with nine longitudinal drillings.  One of these is central, and the other eight are in a ring around the central drilling.  An ignition charge is located in a holder at the forward end of the propellant.  This is fired by the flash from the percussion cap passing up the central hole of the propellant.

The upper tube is the leaflet container and it is closed by a bakelite cap.  The leaflets are contained within a cylinder split longitudinally and are wrapped around a steel spring which is kept under compression.  Below the leaflets, one bakelite washer and two cardboard washers, is the bursting charge, incorporating a delay train which is fired by the heat from the ignition charge for the propellant.

Operation: The operation of this projectile is very simple.  When the heat from the ignition charge ignites the bursting charge, the contents of the upper tube are ejected; as the split cylinder emerges, it falls apart and allows the compressed spring to scatter the leaflets packed around it.

7.3-cm Raketen Sprenggranate

Caliber: 7.29 centimeters

Overall Length: 11.09 inches

Overall weight: 6 pounds

Nature of the fuze: Nose percussion

Warhead Material: Steel

Overall Length: 4.22 inches

Maximum Diameter: 2.85 inches

Diameter at Nose: 0.81 inches

Wall Thickness: Varies from 0.23 inch aft to 0.12 inch forward

Weight of Filling: 0.62 pounds

Overall Length (Body Tube): 6.34 inches

Overall Diameter (Body Tube): 2.6 inches

Wall Thickness (Body Tube): 0.1 inches

Overall Diameter (Base): 2.86 inches

Overall Height (Base): 1.29 inches

Number of Venturi: 14

-7 offset (outer circle)

-7 straight (inner circle)

Description: This is a spin-stabilized projectile of conventional design, consisting of a warhead and a rocket motor.  The projectile is essentially the same as the 7.3cm propagandagranate 41, except that a warhead provided with a percussion fuze and self-destroying delays has replaced the leaflet container.

The projectile is fired from the Fohn Gerat, a 35-frame launcher with fast elevating and transverse gears.  The launcher is capable of firing 35 rockets simultaneously.

The self-destroying feature of the rocket plus the characteristics of the launcher suggest that the projectile is intended for use against low flying aircraft in the form of barrage fire.

Warhead: The warhead is ogival in shape and open at the rear where it is threaded internally to receive the rocket motor.  The explosive filling is a preformed charge of 280 grams of RDX/TNT/wax pressed in a block and wrapped in wax paper.

The warhead is double fuzed, being fitted with a nose percussion fuze and a self-destroying base fuze.  The RAZ 51 is screwed directly into the nose of the warhead.  In the base of the charge is a cavity which accommodates the self-destroying delay, located in a tube screwed into a metal plug int he forward end of the motor.  The delay consists of a quick-fire igniter, initiated by the motor ignition charge, and what appears to be a tracer composition.  When the tracer composition burns out, it flashed through an orifice into a primer-detonator which detonates the main charge.

Rocket Motor: The rocket motor consists of a plane cylindrical body and a cup=shaped base plate.  The body is screwed into the warhead at the forward end and into the flange of the base plate at the rear.  The forward end of the rocket motor has a flange below which is located a metal closing plate which separates the warhead from the propellant compartment and also holds the rear end of the self-destroying assembly for the explosive charge.  Below this plate is a stamped metal supporting ring containing the ignition charge for the propellant.

The base plate, which screws on the rear end of the body, has seven outer offset venturi, seven straight venturi, and a central drilling for a percussion primer. 

The propellant charge consists of a single cylindrical stick with a central perforation and eight outer perforations.  Raised ribs around the circumference of the propellant serve to keep it clear of the motor body and permit external burning.  Two 1/8-inch blocks of powder, cemented tot he base of the charge, act as spacers and keep the venturi free from obstruction.

The charge is ignited by the flash from the percussion primer.  The flash is transmitted along a celluloid tube in the central drilling to the ignition charge at the froward end of the propellant.  The celluloid tube is of conventional design.  It contains a quickmatch train and is closed at each end by a cylindrical block of gunpowder.

Next Time: Rockets (Part 14)

Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters

German Explosive Ordnance - Rockets (Part 12)

German Explosives

A-9 / A-10 Long Range Missile

Description

The A-9 is similar in appearance and results to the A-4b but is of different internal construction.  It was proposed to develop and manufacture the A-9 in place of the A-4; however, this would require much reconversion and the A-4b, which could be put into operation much quicker, was being pushed as a stop-gap.  It was to have a Salbei-Visol rocket motor very similar to the missile Wasserfall.  It is shot into the air like a V-2 and vent toward the target, but rather than falling, it glides over the target where it goes into a vertical dive.  It would travel about 600 km in 17 seconds.

A proposal was made to launch it from a catapult at supersonic speed to increase the range.  It was also proposed to install a pressurized cabin and use a human pilot.  The pilot would drop the warhead on the target and then return to his base.  A retractable landing gear would be used in the landing which, it was felt, could be carried out at a speed as low as 160 km/h. 

Although the A-10 was never built, the calculations were completed for this unit which was to be used as an assist take-off motor for the A-9.  It supplies a thrust of 200 tons and would be jettisoned after it had served its purpose.  When the A-10 is jettisoned, the A-9 would have a velocity of 1,200 meters per second and the A-9 motor would begin to function.  The ultimate velocity was expected to be 2,800 meters per second.  The A-9/A-10 combination was expected to have a range of 5,000 km. 

It was also proposed to use a human pilot in this combination.

Next Time: Rockets (Part 13)

Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters