Analysis of Railgun vs Coil gun technologies

The rail gun and coil gun are both alternative methods of launching a projectile at high speeds compared to conventional chemical methods. If perfected, these technologies could potentially launch projectiles many times farther and faster than current chemical based methods. The US government has already demonstrated a proof-of-concept rail gun weapon, and is set to begin testing a ship-mounted rail gun in the near future.

But what are the main differences between the two technologies? In this page we will explore the physics and conceptual understanding of both the rail gun and the coil gun.

Introduction

The main difference between a rail gun and a coil gun is how each gun propels its projectile.

The rail gun uses Lorentz Force by passing a current through two metal rails and the projectile, causing a magnetic field to be produced that interacts with an external field, and thereby produces force via F = ILB equation.

The coil gun uses simple magnetic configuration to generate the field to propel a projectile. Multiple solenoids are connected in series, and each one is activated sequentially in such a manner to add kinetic energy with each pass of the solenoid.

A Mathematical Model

To generate the massive amounts of energy required to accelerate a projectile to high speeds, capacitors are most often used. They have the capability to provide a large amount of current in a very short amount of time.

Examples

Video of US rail gun:

Video of homemade coil gun: