XB-70 Valkyrie

XB-70 Valkyrie

The North American XB-70 Valkyrie was a nuclear bomber designed for the United States Air Force's Strategic Air Command in the 1950s. The Valkyrie was designed to be a large, high-altitude bomber with six engines to fly at Mach 3 to avoid defending interceptors, the only effective anti-bomber weapon at the time. The development of the Valkyrie caused the Soviet Union to create the MiG-25 "Foxbat" to counter the high speed bomber, along with U-2 and SR-71 reconnaissance airplanes.



The proposed cost of the aircraft, along with changes in the technological environment due to the introduction of the first effective anti-aircraft missiles led to the cancellation of the program. Although the proposed full fleet of operational B-70 bombers was never built, two prototype XB-70s flew in flight tests in the 1960s, performing research on the design of large supersonic aircraft. One prototype crashed following a mid-air collision in 1966, and the other is now on display at the National Museum of the United States Air Force in Dayton, Ohio.

General characteristics

* Crew: 2
* Length: 185 ft 10 in (56.6 m)
* Wingspan: 105 ft 0 in (32 m)
* Height: 30 ft 9 in (9.4 m)
* Wing area: 6,296 ft² (585 m²)
* Airfoil: Hexagonal; 0.30 Hex modified root, 0.70 Hex modified tip
* Empty weight: 210,000 lb (93,000 kg)
* Loaded weight: 534,700 lb (242,500 kg)
* Max takeoff weight: 550,000 lb (250,000 kg)
* Powerplant: 6× General Electric YJ93-GE-3 turbojet, 28,000 lbf (133 kN) each

Performance

* Maximum speed: Mach 3.1 (2,056 mph, 3,309 km/h)
* Cruise speed: Mach 3.0 (2,000 mph, 3,219 km/h)
* Range: 4,288 mi (7,900 km) combat
* Service ceiling: 77,350 ft (23,600 m)
* Rate of climb: ft/min (m/s)
* Wing loading: 84.93 lb/ft² (414.7 kg/m²)
* Thrust/weight: 0.314