First announced in 1954, Pratt & Whitney's J75 engine was developed from its J57 with a similar component arrangement, but with design features emphasizing weight control. Production began in the spring of 1957, and both afterburning and non-afterburning versions were manufactured. J75 engines were rated at 109 to 118 KN (24,500 to 26,500 lb) thrust with afterburner, depending on the model.
The J75 powered the Convair F-106 Delta Dart - the first U.S. operational Mach 2 fighter-, the Republic F-105 Thunderchief fighter-bomber, and North American F-107A. The commercial version, known as the JT4, was certificated in March 1957, and was used on the Boeing 707-220/-320 and the McDonnell Douglas DC-8-20/-30 airliners.
The Lockheed U-2 reconnaissance aircraft was originally powered by the Pratt & Whitney J57 and later by the J75. This J75-P-13B, an experimental Pratt & Whitney engine, was installed in NASM's Lockheed U-2C aircraft to represent the later type of engines used in it.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.