The XB-70, one of the world's most exotic airplanes, was conceived for the Strategic Air Command in the 1950s as a high-altitude bomber that could fly three times the speed of sound (Mach 3). Because of fund limitations, only two were built, not as bombers, but as research aircraft for the advanced study of aerodynamics, propulsion and other subjects related to large supersonic aircraft.
The Tupolev Tu-160 is a supersonic, variable-sweep wing heavy strategic bomber designed in the Soviet Union. Tu-160 is currently the world's largest combat aircraft, largest supersonic aircraft, and largest variable-sweep aircraft built. In addition, the Tu-160 has the heaviest takeoff weight of any military aircraft besides transports. Designed in 1981 and still in production. It was the last strategic bomber designed for the Soviet Union. It can carry 40.000 Kg at 2.220 Km/h.
"This is a 1.79 percent scale model of a concept supersonic aircraft designed by The Boeing Company. You're seeing it through a window in the supersonic wind tunnel at NASA's Glenn Research Center in Ohio. Researchers recently wind tunnel-tested the model's performance while changing the amount of air streaming through inlets you can see near the back of the model, NASA said. The research is part of the agency's work into making supersonic flights quiet enough to go over land." —Francie Diep