The Republic P-47 Thunderbolt is a World War II-era fighter aircraft produced by the American company Republic Aviation from 1941 through 1945. It was a successful high-altitude fighter, and it also served as the foremost American fighter-bomber in the ground-attack role. Its primary armament was eight .50-caliber machine guns, and it could carry 5-inch rockets or a bomb load of 2,500 lb (1,100 kg). When fully loaded, the P-47 weighed up to 8 tons, making it one of the heaviest fighters of the war.