The Bell X-2 Starbuster was an American research aircraft built to investigate flight characteristics in the Mach 2-3 range.
Providing adequate stability and control for aircraft flying at high supersonic speeds was only one of the major difficulties facing flight researchers as they approached Mach 3. For, at speeds in that region, they knew they would also begin to encounter a "thermal barrier", severe heating effects caused by aerodynamic friction.
Constructed of stainless steel and a copper-nickel alloy, and powered by a two-chamber XLR25 2,500 to 15,000 lbf (11 to 67 kN) thrust throttleable rocket engine, the sweptwing Bell X-2 was designed to probe this region and to be the first aircraft to take man well above the measurable atmosphere to the very edge of space.
Following launch from a modified B-50 bomber, Lt. Col. Frank K. "Pete" Everest (1920-2004) completed the first powered flight on November 18, 1955 and, by the time of his ninth and final flight in late July the following year, he had established a new speed record of Mach 2.87 (1,900 mph, 3050 km/h). The X-2 was living up to its promise, but not without difficulties.
At high speeds, Everest reported that its flight controls were only marginally effective. Moreover, simulation and wind tunnel studies, combined with data from his flights, suggested that the airplane would encounter very severe stability problems as it approached Mach 3.
On the morning of September 27, Milburn G. "Mel" Apt was launched from the B-50 for his first flight in a rocket airplane. Flying an extraordinarily precise profile, he became the first man to exceed Mach 3 that day, as he accelerated to a speed of Mach 3.2 (2,094 mph, 3,370 km/h) at 65,500 ft (19,960 m).
Video 1:Toward the unknown bell X2