Electromagnetic guns require pulsed power supplies that deliver energy
to the gun breech in the 2-6 millisecond regime. A flywheel energy st
orage machine in which the disk rotor contains the field excitation wi
ndings appears to be a practical approach to meeting energy/power dens
ity requirements. The general concept of constructing an axisymmetric
disk to obtain a radial to hoop elastic modulus ratio (E(r)/E(theta))
that optimizes the strength of a radially thick disk is presented. A c
arbon fiber - epoxy rotor disk designed to operate at 650 meters pdr s
econd rim speed with a 23% Copper conductor thickness fraction is revi
ewed. Results of sub-scale and/or sub-thickness spin test disks are al
so discussed.