Bell X-2

X-2
Bell X-2 #2 with a collapsed nose landing gear, after landing on the first glide flight, on 22 April 1952 at Edwards Air Force Base.
Role	Research aircraft
National origin	United States
Manufacturer	Bell Aircraft
First flight	18 November 1955 (first powered flight) 27 June 1952 (first drop glide)
Retired	27 September 1956
Primary users	United States Air Force National Advisory Committee for Aeronautics
Number built	2

The Bell X-2 (nicknamed "Starbuster") was an X-plane research aircraft built to investigate flight characteristics in the Mach 2–3 range. (The term "Starbuster" is seldom, if ever, found in contemporary accounts.) The X-2 was a rocket-powered, swept-wing research aircraft developed jointly in 1945 by Bell Aircraft Corporation, the U.S. Air Force and the National Advisory Committee for Aeronautics (NACA) to explore aerodynamic problems of supersonic flight and to expand the speed and altitude regimes obtained with the earlier X-1 series of research aircraft.

The Bell X-2 was developed to provide a vehicle for researching flight characteristics in excess of the limits of the Bell X-1 and D-558 II, while investigating aerodynamic heating problems in what was then called the "thermal thicket".

The Bell X-2 had a prolonged development period due to the advances needed in aerodynamic design, control systems, high-temperature resistant materials to be used, and other technologies that had to be developed. Not only did the X-2 push the envelope of manned flight to speeds, altitudes and temperatures beyond any other aircraft at the time, it pioneered throttleable rocket motors in U.S. aircraft (previously demonstrated on the Me 163B during World War II) and digital flight simulation. The XLR25 rocket engine, built by Curtiss-Wright, was based on the smoothly variable-thrust JATO engine built by Robert Goddard in 1942 for the Navy.

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, K-Monel, and powered by a liquid propellant (alcohol and oxygen) two-chamber XLR25 2,500 to 15,000 lbf (11 to 67 kN) sea level thrust, continuously throttleable rocket engine, the swept-wing Bell X-2 was designed to probe the supersonic region.

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