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82mm M-8 rocket for the BM-8 Katyusha (Stalin organ), Russia, WW2.

pzgr40

Well-Known Member
Premium Member
Cutaway model of a M-8 rocket for the Russian BM-8 Katyusha multiple rocket launcher. BM stands for “Bojevaja Masjina” , what –translated to English- means ‘fighting machine’.
The M-8 is the first type of this rocket, designed in 1936, and used for the first time in a combat role on 7 july 1941 against the German troops in Russia.
The launcher as well as the rockets were easy and cheap to manufacture, and although the rockets were quite inaccurate, the large number of rockets launched nearly simultaniously enshured it was an effective area coverage weapon with a great psycological effect on enemy troops.
At the start of WW2 this weapon was still a well kept secret, and personel serving the launchers was NKVD (secret police) personel. Only when the German Nebelwerfer became common, the weapon was also send to “normal“ troops. The Germans nicknamed the weapon “Stalins organ” after the howling sound of the rocket motors during launch.
One of the advantages of the BM-8 was that it could leave directly after firing, denying the enemy the chance of counter battery fire. A disadvantage however was that he reloading time was quite long compared to normal gun artillery.

Vehicles were modified to allow for launching installations to be placed. The name consisted of the name or brand of the vehicle , followed by the term BM (rocket launcher), the numer 8 for 8cm, and the number of rockets that could be mounted on the launcher.
Twenty-four rockets were placed on the rails of a launcher which was placed on a -land lease- studenbaker U6 truck, the Studenbaker-BM-8-24. Another version was a Zis -6 truck with a launcher for 48 rockets, the Zis6-BM-8-48.
The chasis of the T-60 light tank was adjusted to carry a launcher with 24 rockets , the T60-BM-8-24.
The launchers were also placed on lend lease Willy’s jeeps (BM-8-6) and launchers for 24 rockets on patrol boats.


The rocket Consists of a cast steel warhead with an AMA fuze on top. After firing, the airstream starts rotating the impeller, unscrewing it from the fuze body. After being unscrewed, it falls away, leaving the impact fuze armed. Upon impact, the needle in the fuze is pushed inward into the detonator, igniting the detonator which ignites the booster placed below the fuze. This ignites the main charge in the warhead.
The motor consists of a forged and machined steel pipe with a flange and a rim in top. Both the top as well as the base of the pipe are internally threaded. In top to receive the warhead, in the base to receive the venturi with the pressed sheet steel tail fins.
Inside the motor five powdersticks are place in a circular array. They all have a hole drilled through to enlarge the burning surface of the powdersticks. A grid is placed between the powdersticks and the venturi to prevent loose pieces of broken off burning powderstick to block the venturi. A thin bag of powder is placed between the grid and the powdersticks, a larger bag of powder is placed on top of the powdersticks. Both these bags function as a flash charge to instantaniously ignite all powdersticks in the motor.

One of the things that was a bit of a mystery to me; no ignition could be found in the motor in any drawing or description. Thanks to fellow member Nabob I found out that the M-8 motor has quite an unique way of being ignited; at the end of the launching rail an ignition mechanism with two U- shaped pipes (pict 04) is placed. When placing the rockets on the rails these pipes are rotated to a horizontal position to allow the rockets being slided on the rails, with the rockets in place, they are turned vertical as in the drawing (pict.04). Than the pipes are screwed forward, sticking the pipes into the venturi of the motor. In picture 05 one can clearly see the pipes sticking into the venturi end of the motor. An electrically ignited catridge is placed in the center of the rails side of the U-shaped pipe. Upon ignition of the cartridge, a flame travels through the U-shaped pipe and is blown into the motor, igniting the motor. Therefore the motor needs no ignition of it’s own. Simple and safe….

The Germans -on the receiving end- were very much impressed with the BM-8 rocket launchers and the M-8 rocket and soon copied the Russian design, although with some modifications. In picture 03 one can see the German “8cm raketen sprenggranate” in top of the picture and the Russian M-8 rocket below it for comparison.

Caliber: 82mm
Wingspan: 200mm
Length rocket: 715mm
Weight warhead : 0,64 Kg (1,4 Lb)
Range : 5.900 mtr (6.500 yards)

Regards, DJH
 

Attachments

  • Pict.01 - M-8 Katyusha rocket.jpg
    Pict.01 - M-8 Katyusha rocket.jpg
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  • Pict.02 - warhead M-8 rocket.jpg
    Pict.02 - warhead M-8 rocket.jpg
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  • Pict.03 - comparison M-8 rocket  and 8cm raketen sprenggranate.jpg
    Pict.03 - comparison M-8 rocket and 8cm raketen sprenggranate.jpg
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  • Pict.04 - Ignition mechanism BM-8.JPG
    Pict.04 - Ignition mechanism BM-8.JPG
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  • Pict.05 - T 60 tank chacis with BM-8-24.jpg
    Pict.05 - T 60 tank chacis with BM-8-24.jpg
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  • Pict.06 - BM-8 -48.jpg
    Pict.06 - BM-8 -48.jpg
    57.6 KB · Views: 21
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