The Grumman F9F Panther was the manufacturer's first jet fighter and the US Navy's second. It first flew on the 24 November 1947, the test pilot was Corky Meyer. Propulsion was a Rolls-Royce Nene turbojet built under license by Pratt & Whitney as the J42. Since there was insufficient space within the wings and fuselage for fuel for the thirsty jet, permanently mounted wingtip fuel tanks were added. It was cleared for flight from aircraft carriers in September 1949, from this it was decided to change the engine, the Pratt & Whitney J48-P-2 was selected, it was a copy of the Rolls-Royce Tay, the other engine that was trialed was the Allison J33-A-16. F9F-2s, F9F-3s, and F9F-5s served with distinction in the Korean War, downing six Mikoyan MiG-15s with one F9F loss. The first MiG-15 downed was on 9 November 1950 by US Navy Lieutenant Commander William (Bill) Amen of VF-111 "Sundownders" Squadron flying an F9F-2B. Three more were downed in November 1951, and the other two were downed on the 18 November 1952. The type was the primary Navy jet fighter and ground-attack plane in the Korean conflict.