Although was designed 1953 as long-range escort fighter, development hampered by relatively long development process and continual changes in specs. Final configuration as a single-place air defense fighter, although C strengthened to allow secondary use fighter-bombers. B only used as interceptors in Air Defense Command. RF models both designed for photo recon mission. More of the final 2-seat B model built than any other; served in Vietnam and remained in service well into 1960s. RF-101 took low- altitude photos of Soviet missile sites during 1962 Cuban crisis and of enemy activities in late 60s in SE Asia. Photos taken by RF-101Cs (but especially Vought RF-8G) during Cuban missile crisis resulted in major US/USSR confrontation.