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XB-70 Valkyrie: America’s Mach 3 Super Bσmber Ever Built

Back in the 1960s, the United States had actively developed supersonic aviation, laying the foundation and innovative design for the future of the global aviation industry and simultaneously conducting some of the most daring experiments. And it is one of these that we will be examining today. This was a project clearly ahead of its time, but somehow still failed to garner the deserved response from the military elite.

North American XB-70 Valkyrie

The North American Aviation XB-70 Valkyrie was the prototype version of the planned B-70 nuclear-armed, deep-penetration supersonic strategic bσmber for the United States Air Force Strategic Air Command. Designed in the late 1950s by North American Aviation (NAA), the six-engined Valkyrie was capable of cruising for thousands of miles at Mach 3+ while flying at 70,000 feet (21,000 m).

North American XB-70A Valkyrie in flight. (U.S. Air Force photo)

At these speeds, it was expected that the B-70 would be practically immune to interceptor aircraft, the only effective ωεɑρσռ against bσmber aircraft at the time. The bσmber would spend only a brief time over a particular radar station, flying out of its range before the controllers could position their fighters in a suitable location for an interception. Its high speed made the aircraft difficult to see on radar displays and its high-altitude and high-speed capabilities could not be matched by any contemporaneous Soviet interceptor or fighter aircraft.

The introduction of the first Soviet surface-to-air missiles in the late 1950s put the near-invulnerability of the B-70 in doubt. In response, the United States Air Force (USAF) began flying its missions at low level, where the missile radar’s line of sight was limited by terrain. In this low-level penetration role, the B-70 offered little additional performance over the B-52 it was meant to replace, while being far more expensive with shorter range. Other alternate missions were proposed, but these were of limited scope. With the advent of intercontinental ballistic missiles (ICBMs) during the late 1950s, manned bσmbers were increasingly seen as obsolete.

The USAF eventually gave up fighting for its production and the B-70 program was canceled in 1961. Development was then turned over to a research program to study the effects of long-duration high-speed flight. As such, two prototype aircraft, designated XB-70A, were built; these aircraft were used for supersonic test-flights during 1964–69. In 1966, one prototype crashed after colliding with a smaller aircraft while flying in close formation; the remaining Valkyrie bσmber is in the National Museum of the United States Air Force near Dayton, Ohio.