As part of a plan to build a strategic bomber for deep penetration and nuclear bombing runs during the Cold War, North American Aviation created a stunningly futuristic prototype for its time: the XB-70 Valkyrie.
Designed for the United States Air Force Strategic Air Command in the 1950s, the Valkyrie was capable of achieving Mach 3 while flying at an astonishing 70,000 feet. The Air Force expected its new aircraft to be immune to jet interceptors. The Valkyrie’s speed would require constant switching between radar stations, making it nearly impossible to track.
Nevertheless, the project would eventually come under pressure due to the Soviets’ development of anti-aircraft missiles that negated the bomber’s height and speed advantages. The aircraft’s designers also failed to foresee the development of intercontinental ballistic missiles that could reach even higher speeds and altitudes unparalleled for nuclear delivery.
The XB-70 would become a beautiful but unnecessary piece of aviation technology, and its fate would be sealed with after a tragic accident involving the XB-70’s second prototype…
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 in mid-air with a smaller jet aircraft; the remaining Valkyrie bomber is in the National Museum of the United States Air Force near Dayton, Ohio.
Source: YouTube