Pratt & Whitney J48

The Pratt & Whitney J48, called the JT7 Turbo-Wasp by the company, is a centrifugal-flow turbojet that Pratt & Whitney built under license from Rolls-Royce as a version of the Tay. The Tay was an enlargement of the Nene, which Pratt & Whitney already made as the J42 for the Grumman F9F Panther. The United States Navy expected improved Panthers to need more power, so the parent company of Pratt & Whitney asked Rolls-Royce for a larger engine. Rolls-Royce was by then busy with its axial-flow Avon, so development and production of the Tay passed to Pratt & Whitney in the United States, while Rolls-Royce kept the rights elsewhere. The J48 was about thirty percent larger than the J42 and was built with and without afterburning, with ratings from 6,000 to 8,750 pounds-force. In the 1950s it powered the Grumman F9F-5 Panther and the F9F-6 and F9F-8 Cougar, and its afterburning versions powered the Lockheed F-94C Starfire and the North American YF-93.