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8cm Raketen sprenggranate

pzgr40

Well-Known Member
Premium Member
Cutaway model of a 8cm Raketen sprenggranate.
The 8cm Raketen sprenggranate was originally meant for the 8cm Vielfachwerfer (multiple launch system), a German copy of the Russian BM-8 Katyusha. The German troops encountered the BM-8 during their campaign in Russia and were much impressed by the weapon. The BM-8 was much more easy to manufacture than the 15cm Nebelwerfer.
It was however difficult to divert existing production capacity to this new weapon. Therefore the waffen-SS started it’s own production line of the 8cm Raketen sprenggranate and the Vielfachwerfer, hence called the ‘Himmler ‘s organ’.
Later on, rockets were delivered to the Luftwaffe for air to ground rocket usage.

The rocket consists of a cast iron warhead with a simple impact fuze with no safety mechanism screwed into the nose end. At the base, the warhead is screwed into an intermediate flange, which is screwed into the top side of the motor. The safety mechanism is placed in the centre of this intermediate flange.
The warhead is filled with three pre-formed rings of explosives, locked up by two cardboard washers at the base.
In the centre, a steel pipe containing the booster charge is placed. In top of this pipe the duplex detonator is screwed. The steel pipe is placed in a cardboard pipe, placed in the explosive charge.
The steel pipe is kept in the rearward position by a spring loaded long screw, kept in backward position by a lead ring. This lead ring is placed in the steel cup at the lower side of the intermediate flange centre. When the pipe with the booster and duplex detonator is in backward position (safe), the firing pin cannot reach the firing cap (red) of the duplex detonator. As soon as the rocket motor is started, the heat inside the motor will melt the lead ring and allow the spring to move the pipe with the booster and duplex detonator to move forward, so the firing pin of the fuze can reach the firing cap (red) upon impact.
The motor consists of a steel pipe, screwed over the intermediate flange on the top side, and a tail and venturi piece screwed into the base of the pipe. Four T-shaped rail mounting notches are placed on the outside of the motor, allowing the rocket to be placed on rails.
The motor is filled with six sticks of Diglycol powder, with a hole drilled through to allow for a larger burning area after ignition. An electric igniter is placed in top of the propulsion charge with a small bag of black powder above it to boost the ignition.
Between the venturi and the powder sticks a steel grid is placed, ensuring no burning parts of powder sticks will block the venturi, causing deviations in the path of the rocket.
The tail fins are made of pressed sheet steel. Two mirrored pieces are spot welded together, forming a 5mm thick fin. The four fins are placed under a 2 degrees angle, to induce spin after firing.

The ignition of the rocket motor has been made after drawing :
“Schnittzeichnung einer >>panzerblitz 1<< bordrakete. Englische orginalzeichnung des air ministery nach der am 1.1. 1945 bei Asch/Holland erbeuteten FW 190.”
As this drawing is very precise I assume the rocket on the drawing was taken apart for measuring and drawing purposes, as the drawing would not have been that detailed if not.
With the ‘normal’ Panzerblitz a shaped charge is placed in the warhead, either a panzerschreck warhead is placed on the rocket.
Supposedly there also was a High explosive rocket available.

With the 8 cm Raketen sprenggranate used with the waffen-SS Vielfachwerfer an ignition charge was placed below the powder sticks, placed over the grid. A spring loaded pin, placed through the afterward T-shaped rail mounting notch ensures the electric ignition of this ignition charge.

Length rocket : 704mm
Siameter Rocket body : 78mm
Diameter over wings : 203mm
Weight complete rocket : 6,88 kg
Weight warhead : 2,86 kg
Weight explosive charge : 0,60 kg
Weight propellant sticks : 0,99 kg
Maximum range : 5760 mtrs

Regards, DJH.
 

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  • 03 - 8cm raketen sprenggranate warhead detail.jpg
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  • 04 - 8cm raketen sprenggranate melting ring.jpg
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  • 05 - drawing 8cm raketen sprenggranate.jpg
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  • 06 - 8cm raketen  vielfachwerfer.jpg
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Great cutaway, thank you for posting!
With the 8 cm Raketen sprenggranate used with the waffen-SS Vielfachwerfer an ignition charge was placed below the powder sticks, placed over the grid. A spring loaded pin, placed through the afterward T-shaped rail mounting notch ensures the electric ignition of this ignition charge.
According to a description of the ground launched variant, I've once made (sadly I havent't indicated sources :( , so I have no idea, how reliable it is), two igniters with blackpowder charges were coupled with the rear T-guides, while there was additional blackpowder charge at the forward end of the combustion chamber. Due to presence of the igniters, two propellant sticks were shorter then the remaining four, supported by the igniters rather than the grid.

Raketen_2D_2012_Lite_color_800_RZ73NF.jpg
 
There is documentation in the archive in Brno.
Attached is a picture from this documentation with the ignition variant at the T slots.

Bob
 

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