This article comes from Interesting Engineering. “Have you heard of the XB-70 Valkyrie? According to NASA, “with a planned cruise speed of Mach 3 and operating altitude of 70,000 feet, (the XB-70) was to be the ultimate high-altitude, high-speed manned strategic bomber.”
Unfortunately, the aircraft was under development at a time, during the 1950s and 1960s, when the future of the manned bomber was uncertain and the focus had shifted to missiles. As a result, the Kennedy Administration canceled plans to deploy the B-70, leaving two experimental XB-70A prototypes unfinished at North American Aviation.
In 1961, President Kennedy revealed that the XB-70 program was to be reduced to research only, citing high cost (over $700 million per prototype) and vulnerability. ” Click here to read the rest of this article.