XB-70 Valkyrie is the largest and fastest bomber that the US ever built. It was 185 feet long,105 feet wide And 30 feet tall.
The XB-70 Valkyrie could cruise at Mach 3 and could hit altitudes of 70,000 feet.
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But the XB-70 Valkyrie never went into full-scale production. The XB-70 Valkyrie made its maiden flight in September 1964. The first XB-70 Valkyrie built, the XB-70A, had handled at speeds greater than Mach 2.5, and only got above Mach 3 once. So a second one was built, the XB-70B, with the wings, adjusted just 5 degrees, which helped to handle. The XB-70B flew for the first time in July 1965.
It had six General Electric J-93 turbojets, each providing the XB-70 with 30,000 pounds of thrust.
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The XB-70 was developed in the 1950s to outrun enemy interceptors and air defenses but ended up being doomed by the birth of surface-to-air missiles.
In 1961, President John F. Kennedy scratched the XB-70 as an actual bomber program — but the aircraft continued to fly for research purposes until February 1969.
The XB-70 continued flying for research purposes until February 1969, and much of the research done contributed to the development of the B-1 bomber.
In October 2015, the only remaining XB-70 was moved into a new building at the National Museum of the US Air Force. The only one left in the world, sitting on display at The National Museum of the US Air Force in Dayton, Ohio.