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