The Republic P-47 Thunderbolt is a monoplane fighter aircraft designed and produced by the American aircraft manufacturer Republic Aviation. Designed around the powerful Pratt & Whitney R-2800 Double Wasp 18-cylinder radial engine and produced from 1941 through to 1945, it became the foremost American fighter-bomber in the ground-attack role during World War II. When fully loaded, the P-47 weighed up to eight tons, making it one of the heaviest fighters of the conflict. It is the namesake of a later U.S. ground-attack aircraft, the Fairchild Republic A-10 Thunderbolt II.