F4U Corsair / French NavyF4U Corsair French Navy airplane model. The F4U 7, built for the French Navy, completed the venerable Corsair line. Essentially the same as an F4U 4 in an F4U 6 (AU 1) airframe, it was equipped with a Pratt and Whitney two speed, two stage engine (R 2800 18W), making it a high altitude fighter. In 1952, the F4U 7 was used by the French in Indochina the Corsairs third war. For 13 years (1940 through 1952), F4U Corsairs were produced for the U. S. Navy.