Michael Karner

Abstract:

A rail gun is a system that accelerates a projectile by passing current through the projectile along the path of two rails in a magnetic field, which is usually created by the current. Our system is an exciting demonstration of some of the underlying principles of electromagnetism, and their effects in the physical world. As an example, the US Navy’s rail gun accelerated a 3.2kg projectile to over 2.2km/s, which is about 8MJ of kinetic energy. After using a few different setups made for a variety of projectiles, we found that rolling a thin graphite rod along the rails at a voltage supplied at no higher than 100V yielded the most stable acceleration. With the magnetic field of 0.6T being supplied along the rail path by permanent magnets, supplied current at around 50A accelerated a 0.6g projectile to speeds as high as 6m/s.