Sunday 17 August 2014

HEAT Tester

Since HEAT does not depend on the velocity of the shell, testing it is easy, all you have to do is hold a shell up against an armour plate, and detonate the charge. No need for large proving grounds or anything costly like that!

Except, there is one problem. Shells fired from rifled barrels without stabilization had different results when tested in this manner, whereas fin-stabilized shells had the same results. In order to test rotating shells, this device was invented.

"The device for testing rotating shells is made from a Г-shaped piece of metal. One end of the device is attached to the ground in proximity to the plate. The other houses a 50-105 Watt electric motor, which provides a rotation of 10,000 RPM when connected to a 30 V power supply, and 20,000 RPM when connected to a 40 V power supply. The axis is positioned vertically. 

The shell was rotated with a thin steel string, one end of which was connected to the motor, the other to the detonator. The motor was powered by a 220 V power supply through a transformer. The rotation of the shell was measured with a tachometer. When the shell reached the necessary rotation speed, it was detonated with a PM-1 device, where one terminal was connected to the shell casing with a metal loop, and the other was connected to the spinning wire."

1 comment:

  1. This was a very good idea. Considering the rifling twist in calibers on a F-34 cannon is 1:25.
    76.2mm x 25 = 1905mm.
    One rotation for every 25 calibers is one rotation each 1.905 meters.
    With a MV of 355m/s for the BR-353A HEAT then that is 355/1.905 = 186.3 rps.
    In other words 11,181 rpm.