The Sageburner set a low altitude speed record, 900 mph at 140 feet altitude.
The F-4 project began 1953 in response to Navy request for a twin- jet, all-weather, supersonic, attack fighter. Development phase long and laborious--made longer by unexpected change in Navy specs which came after contract for 2 prototypes had been awarded Oct 54. Fundamental changes made in specs to make primary role long-range, high altitude interceptor. Proposed cannon armament abandoned in favor air-to-air missiles, and second crew member added as radar operator. By end 1958, Phantom II selected by Navy over Chance Vought Crusader III as new standard equipment for Navy squadrons. Original contract for 2 YAH-1s changed to 23 pre-serial F4H-1 test aircraft. At end of long proving trials, 649 B models, first production version, ordered and entered service 1961. In response to USAF interest, improved C model developed; substantially resembled B (Navy carrier) model. Prototype C flew May 63; 583 built. 1965, D model, also for USAF, with more powerful engines and improved avionics ordered; 843 built.