Experimental results from a 4-stage synchronous induction coilgun
To demonstrate the multi-stage induction launch capability and test the accuracy of the simulation result, a small-scale, 4-stage synchronous induction coilgun has been 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 accelerate a projectile. Inductance of the four coils is tailored by changing the number of turns in order to decrease the pulsed current risetime. Tracking of the projectile location during launching provides precise feedback to control when the coils were triggered to create this wave. Two types of the projectiles were tested. A 0.65-kilogram sleeve projectile was accelerated from rest to 125 m/s with a projectile kinetic energy to capacitor stored energy efficiency of 6 %. A 1-kilogram sleeve projectile was accelerated from rest to 92m/s with the efficiency of 5 %. The solenoid projectile was broken at the bending point when it was induced high current. This launcher provides data for model verification and the engineering basis for proceeding with larger multi-stage system. Further research will focus on improving the system efficiency and maximizing the magnetic coupling between the driving coil and projectile.