Pratt & Whitney J48

The Pratt & Whitney J48  (company designation JT7 Turbo-Wasp) is a turbojet engine developed by Pratt & Whitney as a license-built version of the Rolls-Royce Tay. The Tay/J48 was an enlarged development of the Rolls-Royce Nene (Pratt & Whitney J42).

Design and development
In 1947, at the behest of the United States Navy, Pratt & Whitney entered into an agreement to produce the Rolls-Royce Nene centrifugal-flow turbojet engine under license as the J42 (company designation JT6), for use in the Grumman F9F Panther fighter aircraft. Concerned that the Nene would not have the potential to cope with future weight growth in improved versions of the Panther, Luke Hobbs, vice president of engineering for P&W's parent company, the United Aircraft Corporation, requested that Rolls-Royce design a more powerful engine based on the Nene, which Pratt & Whitney would also produce.

By 1948, Rolls-Royce had designed the Tay turbojet, also a centrifugal-flow design. However, as Rolls-Royce was then developing an improved design with an axial compressor, which would become the Avon, the development and production of the Tay turbojet was left to Pratt & Whitney. However, Rolls-Royce retained the rights to the Tay outside of the United States.

The Tay/J48 was a thirty percent enlargement of the preceding Nene/J42, and was produced both with and without afterburning.

Operational history
Several aircraft types used the J48 engine during the 1950s, including the Grumman F9F-5 Panther. and Grumman F9F-6/F9F-8 Cougar, The U.S. Air Force's Lockheed F-94C Starfire and North American YF-93 used afterburning versions of the J48 engine.

Variants
Data from The Engines of Pratt & Whitney: A Technical History.


 * J48-P-1: 6000 lbf dry, 8000 lbf thrust with afterburning
 * J48-P-2: 6250 lbf, 7000 lbf thrust with water injection
 * J48-P-3: 6000 lbf, 8000 lbf thrust with afterburning
 * J48-P-5: 6350 lbf, 8750 lbf thrust with afterburning
 * J48-P-6: 6250 lbf, 7000 lbf thrust with water injection
 * J48-P-6a: 6250 lbf, 7000 lbf thrust with water injection
 * J48-P-7: 6350 lbf, 8750 lbf thrust with afterburning
 * J48-P-8: 7250 lbf thrust
 * J48-P-8A: 7250 lbf thrust
 * Turbo-Wasp JT-7: Commercial engines / company designation

Applications

 * Grumman F9F-5 Panther
 * Grumman F9F-6/-8 Cougar
 * Lockheed F-94C Starfire
 * North American YF-93