Friday 26 December 2014

Rocket Bike

If you've looked into the Soviet M-72 motorcycle, you would probably know that they put all sorts of stuff on top of it: machineguns, anti-tank cannons, light mortars. Today, you can add rocket launchers to that list.

"Report #6877
On the RUM-12 launcher trials

Objective: discover the feasibility of arming motorcycle troops with 82 mm rocket launchers.

Trials were carried out at the Sofrino artillery proving grounds on September 8th, 1941, following NII-3 #1454s directives signed on September 6th, 1941.

Trial details:

The RUM-12 was designed and assembled by factory #487. The launcher consists of a motorcycle with 12 stock aircraft 840 mm rocket rails mounted instead of the sidecar, equipped with pyropistols.

An aircraft ring sight is installed for aiming, as well as a shield to protect the shooter from gases and a control device to activate the pyropistols.

24 rockets were supplied by NII-3, of which:
  1. 12 were equipped with TNT warheads and AM-a. detonators. The rockets were equipped with BPP 203/50-1/36-K propellant (22 rods per charge) and a 12 gram DRP primer.
  2. 12 were equipped with sulfur warheads. An 18x33 mm TNT charge was inserted, and a stock AM-a detonator was used.
Conditions of trials:

Two groups were fired off to determine groupings.
  1. 12 rockets with fast-burning BPP propellant. The rockets did not have ballistic caps on, and the vanes had additional rods welded to them. The angle of elevation was 3.5 degrees.
  2. 12 rockets with stock nitroglycerin propellant. The rockets used ballistic caps and stock vanes. The angle of elevation was 3.5 degrees.
Results of trials:

Precision of rockets with fast-burning propellant:


Rockets fired
Acceptable shots
Elevation
Mean deviations
Average range
Length (m)
Length (arc)
Width (m)
Width (arc)
Required
Length
Width
12
6*
3.5 degrees
158.1
1/12
35.7
1/52
1/10
1/50
1854

* 6 shots were practice shots. The first tore off two rockets with the exhaust, deformed the vanes on some rockets, and punched through the detonator membrane on one of the rockets. In order to avoid the aforementioned problems, the rest of the shots were made from a partially loaded launcher (3-6 rockets).

Precision of rockets with regular nitroglycerin propellant:

Of 12 shots fired, 6 dipped, falling about 50 meters from the launcher. The other six were significantly scattered width-wise. The dispersion was not measured. No damage to vanes was observed, even thought the rockets were shot from a fully loaded launcher. One shot tore off a pyropistol, likely due to poor assembly at the factory.

During firing from both the first and second groups, the motorcycle was shifted sideways noticeably. The angle of elevation was altered negligibly.

Conclusions:
  1. 82 mm rockets with fast burning BPP propellant can be effectively used by motorcycle forces, given that the AM-a detonator is replaced with another detonator (try using the GMVZ detonator).
  2. Stock 82 mm rockets can also be used, but with reduced effectiveness, due to their tendency to dip when fired from short ground based launchers.
  3. It is necessary to:
    1. Increase the stability of the motorcycle.
    2. Improve the aircraft ring sight. The sight supplied with the launcher could only be used with a quadrant, which had to be installed on the launcher itself, due to a lack of mounting surfaces on the sight."

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