AN INSTRUMENT FOR THE STUDY OF THE INITIAL STAGES OF GUN RECOIL
NAVAL PROVING GROUND DAHLGREN VA
Pagination or Media Count:
The device consists of a resistance strain gage mounted on a steel strap which is bolted at one end to a nonrecoiling portion of the gun mount and at the other to a recoiling section. The band is mounted parallel to the direction of recoil motion, with an initial small stress to eliminate slack. The strain gage is 1 arm of a bridge circuit the output of which is fed into a high- gain dc amplifier and controls the deflection of a CRO beam. Oscillograms from 4 rounds fired in a 3-in.70-cal Type E Mod 0 gun to compare the recoil strap with an oil-damped recoil switch indicated that 1 the recoil strap shows the start of the recoil before it is indicated by the oil-damped switch, and 2 the strap records a slight forward motion of the gun preceding recoil. An accuracy of or - 0.5 msec was obtained with the recoil strap in determining the beginning of recoil. The breech pressure at the start of recoil on 16 rounds varied from 1650 to 2000 psi as measured with the recoil strap. This was a considerably narrower range of pressures than that indicated by the recoil switch. Investigations are being made of the utility of the recoil strap in studying 1 the frictional forces between the projectile and the bore surface during engraving and 2 the frictional forces involved in the initial movement of the recoil masses.