The 001 prototype featured two low-power NPT301 turbojets from Noel Penney Turbines (NPT) Ltd. in Coventry, England. The converted missile engines were intended solely for the 001, and NPT was slated to develop new engines for the final version of the aircraft. But when NPT went bankrupt, the entire Leopard project was delayed for one year until CMC teamed up with Williams International Corp., Walled Lake, Michigan.
Williams developed the FJX-1 engine for CMC’s first production-configured aircraft the 002, built at the Designability R&D Center in Dilton Marsh, England.
Rated at 540 lb-thrust, the Williams FJX-1 had more than twice the power of the NPT301. That was okay for the 002, but it was not quite enough for the final Aircraft.