The engine had a nine-stage compressor with an 8.8:1 pressure ratio. The engine made extensive use of high temperature nickel superalloys, especially Inconel and Waspaloy, to withstand temperatures ranging from 800° F (about 430° C) in the inlet to 3200° F (1760° C) in the afterburner duct.Īir to air three-quarter-front view of a 9th Strategic Reconnaissance Wing SR-71 Black Bird as it approaches a tanker for refueling. The Pratt and Whitney J-58 engine was a dual cycle engine, the first of its kind, as it worked as a standard afterburning turbojet at subsonic and transonic speeds and then switched to a ramjet-like behavior at around Mach 2, providing more than 32,000 pounds of thrust at sea level. The myth surrounding the Blackbird (we could say the secret of its success) is also due to the fact that no one has ever been able to replicate (at least publicly) the technology contained into its distinctive engine nacelles: the Pratt and Whitney J-58 turbojet engines and the air inlets, the key factor that made possible to reach the maximum speed of Mach 3.2.

The Lockheed SR-71 “Blackbird”, the famous high-altitude Mach 3 reconnaissance aircraft designed by Kelly Johnson at Lockheed’s Skunk Works division, is still holding, as of 2019, the record for the fastest air-breathing manned aircraft, established in 1976. The air inlets were the key factor that helped the J-58 engines to provide 32,000 pounds of thrust and allow the Blackbird to reach Mach 3.2.

Nacelle code system shock 2