Formal U.S. Navy acceptance trials for the XF4U-1 began in February 1941. The Navy entered into a letter of intent on 3 March 1941, received Vought's production proposal on 2 April, and awarded Vought a contract for 584 F4U-1 fighters, which were given the name "Corsair" – inherited from the firm's late-1920s Vought O2U naval biplane scout which first bore the name – on 30 June of the same year. The first production F4U-1 performed its initial flight a year later, on 24 June 1942. It was a remarkable achievement for Vought; compared to land-based counterparts, carrier aircraft are "overbuilt" and heavier, to withstand the extreme stress of deck landings.