XB-70 Valkyrie: The insane engineering of the US’ fastest bomber jet

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. 

Two XB-70s flew 

According to the National Museum of the United States Air Force, the United States Air Force did buy two XB-70As to test the aerodynamics, propulsion, and other traits of the large supersonic aircraft. The first XB-70A flew in September 1964, achieved Mach 3 flight in October 1965, and continued to fly and generate valuable test data in the research program until it came to the museum in 1969. The second Valkyrie first flew in July 1965 but was destroyed following an accidental mid-air collision in June 1966. A third Valkyrie was never completed.

What was the impressive aircraft like?

The XB-70 had a length of 196 feet, a height at the tail of 31 feet, and an estimated maximum gross weight of 521,000 pounds. It took a crew of four people to fly this massive jet: a pilot, a copilot, a bombardier, and a defensive systems operator.

The jet could achieve supersonic speeds of up to Mach 3. At this speed, the plane was designed to ride its own shock wave. The aircraft was built using titanium and brazed stainless steel “honeycomb” materials to allow it to withstand the heating during the sustained high Mach number portions of the flights.