MICROWAVE MEASUREMENTS OF PROJECTILE MOTION IN THE BARREL OF THE UTIAS IMPLOSION-DRIVEN HYPERVELOCITY LAUNCHER.

A microwave-Doppler method is applied to measure the velocity of a projectile inside the barrel of the UTIAS Implosion-Driven Hypervelocity Launcher. The microwave-Doppler method and its application for this particular case are discussed in detail. The measurements concentrate on the gas case, in which the driven gas is only a stoichiometric mixture of hydrogen and oxygen, without explosive PETN, for initial pressures between 200 and 600 psi. It is clearly shown that the projectile is accelerated by subsequent pressure pulses caused by multiple implosions inside the chamber. The effect of the subsequent implosions on the motion of the projectile decreases with increasing velocities and for velocities greater than approximately 8000 ftsec only the first implosion seems to be important. The muzzle velocities in this experiment could be compared with earlier measurements and are in good agreement. A numerical calculation, describing the projectile motion only during the first pressure pulse also agrees with the measurements. Finally, earlier results of muzzle velocity for gas and explosive cases are discussed and some general remarks with respect to possible losses in the driving mechanism are made. Author