Patent ID: 7409900

Claim:
An electromagnetic launcher for accelerating a projectile from an initial speed at a breech end to a launch speed at a muzzle end, the launcher comprising: a container having an inner surface along an axial direction; a rail contained within the inner surface, the rail having a load surface to support the projectile and an interface surface; and a support between the interface surface and the inner surface, wherein the rail and the support provide a value to an expression for critical velocity V cr = 2 ⁢ EIk ρ ⁢ ⁢ A , where E is Young's modulus for the rail, I is moment of inertia for a cross-section of the rail, k is foundation modulus for the support, ρ is density for the rail and A is a cross-sectional area of the rail, the critical velocity increases along the axial direction towards the muzzle; and the critical velocity continuously exceeds an accelerating speed of the projectile between the initial speed at the breech end and the launch speed at the muzzle end.