It looks something like a Concorde, But the XB-70 Valkyrie was designed to be a high altitude strategic bomber. The XB-70 or B-70/NA-278 project was designed by North American Aviation engineers, It was to have a service altitude of 100,000 feet,a cruising speed of Mach 2, and a "dash performance" of Mach 3.The range was 6000 miles before re-fueling was required,Ethyl Borane fuel enhanced the bombers performance at high altitude.Six General Electric engines were used to push the envelope at about a little over Mach3., 70% of the aircraft was built from a new type of stainless steel skin, and the Aircraft was built in one large section using the "Honey combed sandwich" type of fuselage construction....On October 15, 1965, The XB-70/B-70 Bomber reached a maximum speed of Mach 3.