B-70 Valkyrie

Built for the U.S. Air Force by North American, the B-70 Valkyrie (or XB-70 when deemed purely experimental) was intended as the ultimate high-altitude penetrating heavy bomber, with Mach 3 speed. Improved Soviet air defenses, however, led to its cancellation as a military aircraft. The U.S. Strategic Air Command changed its approach to low-level penetration with improved B-52H bombers, as well as increased emphasis on intercontinental ballistic missiles. Attempts were made to find a military role, but the airframe was not suitable to low-altitude penetration. It was considered as a reconnaissance aircraft, but it had an immensely greater radar cross section than the purpose-built, faster SR-71.

Two were built, and eventually transferred to the National Aeronautics and Space Administration for research in high altitude, high speed flight. It first flew in 1964, and reached Mach 3 14 October 1965. The No. 2 airplane first flew on July 17, 1965, but on June 8, 1966, it crashed following a mid-air collision. The No. 1 airplane continued in its research program until flown to the museum on Feb. 4, 1969.

Characteristics

 * Wingpan: 105 ft.
 * Length: 185 ft. 10 in. without boom; 192 ft. 2 in. with boom
 * Height: 30 ft. 9 in.
 * Weight: 534,700 lbs. loaded
 * Armament: None in research role
 * Engines: Six General Electric YJ-93s of 30,000 lbs. thrust each (with afterburner)
 * Maximum speed: 2,056 mph (Mach 3.1) at 73,000 ft.
 * Cruising speed: 2,000 mph (Mach 3.0) at 72,000 ft.
 * Range: 4,288 miles
 * Service ceiling: 77,350 ft.