The Grumman F6F Hellcat was a United States Navy carrier based fighter aircraft developed to replace the earlier F4F Wildcat. Although the F6F bore a family resemblance to the Wildcat, it was a completely new design powered by a 2,000 hp Pratt & Whitney R-2800. Some tagged it as the "Wildcat's big brother". The Hellcat and the Vought F4U Corsair were the primary USN fighters during the second half of World War II. The Hellcat proved to be the most successful aircraft in naval history, destroying 5,171 aircraft while in service with the U.S. Navy and U.S. Marine Corps (5,163 in the Pacific and eight more during the invasion of Southern France), plus 52 with the Royal Navy's Fleet Air Arm during World War II. Postwar, the Hellcat aircraft was systematically phased out of front line service, but finally retired as late as 1954 as a night-fighter in composite squadrons.