The Lockheed YF-12 was a prototype interceptor Mach 3+

 The Lockheed YF-12 was a prototype interceptor Mach 3+, based on the A-12 Oxcart design, and a prototype model SR-71. Only three were built and only one remains today. The YF-12A program was canceled in the late 60 due to financial reasons. However, the remaining aircraft remained in service at NASA to its final withdrawal in 1979.

                             An AIM-47A waiting to be loaded aboard a YF-12.             

 

• General characteristics
• Crew: 2
• Length: 101 ft 8 in (30.97 m)
• Wingspan: 55 ft 7 in (16.95 m)
• Height: 18 ft 6 in (5.64 m)
• Wing area: 1,795 ft² (167 m²)
• Aspect ratio: 1.7
• Empty weight: 60,730 lb (27,604 kg)
• Loaded weight: 124,000 lb (56,200 kg[6])
• Max. takeoff weight: 140,000 lb (63,504 kg)
• Powerplant: 2 × Pratt & Whitney J58/JTD11D-20A afterburning turbojet with compressor bleed bypass
• Dry thrust: 20,500 lbf (91.2 kN) each
• Thrust with afterburner: 31,500 lbf (140 kN) each
• Performance
• Maximum speed: Mach 3.35 (2,275 mph, 3,661 km/h[6]) at 80,000 ft (24,400 m)
• Range: 3,000 mi (4,800 km)
• Service ceiling: 90,000 ft (27,400 m)
• Rate of climb: 11820 ft/m (60 m/s) ()
• Thrust/weight: 0.44
• Armament
• Missiles: 3× Hughes AIM-47A air-to-air missiles located internally in fuselage bays