DAYTON, Ohio - The Pratt & Whitney J58 Turbojet engine on display in the Cold War Gallery at the National Museum of the U.S. Air Force. (U.S. Air Force photo)
The J58 engine was developed in the late 1950s by Pratt & Whitney Aircraft Division of United Aircraft Corp. to meet a U.S. Navy requirement. It was designed to operate for extended speeds of Mach 3+ and at altitudes of more than 80,000 feet. The J58 was the first engine designed to operate for extended periods using its afterburner, and it was the first engine to be flight-qualified at Mach 3 for the Air Force.
Two J58s power the highly-sophisticated Lockheed SR-71 high-altitude strategic reconnaissance aircraft as well as its forerunner, the Lockheed YF-12A prototype interceptor. In July 1976 J58 engines powered an SR-71 to a world altitude record of 85,069 feet and another SR-71 to a world speed record of 2,193 mph.
Because of the high-temperature environment in which the engine operates, it uses low-volatility JP-7 fuel which requires a chemical ignition system.
The engine on display is a prototype version of the J58 and was used as a ground trainer before being transferred to the museum.
TECHNICAL NOTES: Model: J58 Compressor: Nine-stage, axial flow, single spool Turbine: Two-stage axial flow Weight: Approx. 6,000 lbs. Thrust: 32,500 lbs. (with afterburner) Maximum operating altitude: Above 80,000 ft.
