Rolls-Royce/Snecma Olympus 593

The Rolls-Royce/Snecma Olympus 593 was an Anglo-French two-shaft turbojet with reheat that powered the supersonic airliner Concorde. It began as a joint project between Bristol Siddeley Engines and Snecma, derived from the Olympus 22R that had been designed for the BAC TSR-2, and Rolls-Royce acquired Bristol Siddeley in 1966 while the engine was still in development. Partial reheat gave a 20 percent thrust increase for take-off and for the transonic acceleration to Mach 1.7, above which Concorde flew supersonically without reheat. Both compressors had seven stages, built of titanium except for the last four high-pressure stages, which were a nickel alloy. Until regular commercial Concorde flights ceased in October 2003 it was the only turbojet with reheat powering a commercial aircraft, and its overall efficiency in supersonic cruise was about 43 percent.