Experimental Results From a 4-Stage Synchronous Induction Coilgun

To demonstrate the multistage induction launch capability and test the accuracy of the simulation result, a small-scale, 4-stage synchronous induction coilgun is designed, fabricated, and tested based on the simulation result. The four coils are stacked end-to-end, forming a barrel, and each coil is energized by the identical pulsed power supply in sequence to create a traveling magnetic wave that accelerates a projectile. The inductance of four coils is tailored by changing the number of turns in order to decrease the pulsed current risetime. The tracking of the projectile location during a launching provides a precise feedback to control when the coils are triggered to create the wave. Two types of the projectiles are tested. A 0.65-kg sleeve projectile is accelerated from rest to 125 m/s with a projectile kinetic energy to capacitor-stored energy efficiency of 6%. A 1-kilogram sleeve projectile is accelerated from rest to 92 m/s with the efficiency of 5%. The solenoid projectile is broken at the bending point when it induces high current. The launcher provides data for model verification and the engineering basis for proceeding with larger multistage system. Further research is to improve the system efficiency and maximize the magnetic coupling between the driving coil and the projectile.