PzGr40
16.07.2004, 20:48
Cutaway model of a 15 cm R.Gr.19/40 L/5,9, meaning; 15 cm rocket Grenade type 19/40 , with a Length of 5,9 times the calibre (5,9x150=885 mm long), including the fuze. The shell was meant for the Sfh.18, a much used piece of heavy German arttilery. The lower part of the shell is the exploder, existing of a cast steel body through which a central venturi pipe is screwed in the top of the body. The venturi is locked up by a bottom plate and a threaded locking ring with a lead gasket in top. The top half of the shell exists of a ogive forged rolled body, threaded in top to receive a ZZ S/30 and also hold a powder magazine with a non return valve. This part forms the rocket engine. Screwed on top of the lower body is a grid, that enshures that no large broken off blocks of burning propellant can block the venturi pipe's entrance. The fuze to explode the main charge is unknown, it is screwed in the top of the lower body. A piece of badly corroded aluminium dummy was in place and has been copied to it's original dimensions. One part of the shell is missing: it's conical bottomplug , preventing the rocket engine from being ignited prematurely when fired by the gun. Functioning of the shell: as this shell was meant for long distance, it was fired most probably with the most powerfull charges available , the No.7 or 8 ( sonderkartuschen). The ZZ S/30 was set to ignite just before the highest point of it's trajectory, the flame of the ZZ S/30 traveling down through the four holes of the non return valve, into the powder magazine under the fuze. This ignites the mian powder stick , pressing out the bottom plug and the shell is thus extended in range by help of rocket assistence. As the pressure in the engine rises , the non return valve is pushed upward and closes, thus preventing leakage of gas to the fuze. At impact the unknown type fuze in the upper part of the lower body explodes the shell. It must be remarked that the shell's explosive charge is about half a meter above the ground on impact , thereby greately improving the effective area covered with splinters (the 15 cm nebelwerfer has same advantadge). Normally the average range for a 15 cm HE shell for the Sfh.18 was about 13.325 mtrs. with the adding of the rocket moter it was 20.000 mtrs. (according to pawlas) German sources report two types of R.A shells for the Sfh.18: The type here described; On January 28, 1945, it was still in it's experimental stadium, the cause being the "treibstoff -explodierer" or ""fuel igniter" of the rocket. The other experimental type is the 15 cm R.Gr. 19 L/4,5 (804 mm long). It had it's explosive charge in the nose and was fuzed with a Kz.28. The Rocket engine in the lower part of the shell was ignited by a bottomfuze (BdZ). This type had already been put into service in small numbers, to be tested by the troops ( Trupenversuch). According to pawlas it's range should be 18.200 mtrs at a speed of 505 m/s. No drawings of these shell are known to me.