The first of the rocket-powered research aircraft, the X-1 (originally designated the XS-1), was a bullet-shaped airplane that was built by the Bell Aircraft Company for the US Air Force and the National Advisory Committee for Aeronautics (NACA).
The mission of the X-1 was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the “sound barrier”.
The XS-1 program not only proved that humans could go beyond the speed of sound, it reinforced the understanding that technological barriers could be overcome.
Many structural and aerodynamic advances were pioneered by the original XS-1s, including extremely thin, yet exceptionally strong wing sections, supersonic fuselage configurations, control system requirements, powerplant compatibility, and cockpit environment.
For the first time in a transonic-capable aircraft, an all-moving stabilizer was utilized. The flights of the XS-1‘s opened up a new era in aviation.
THE X-1 SERIES
Three X-1s were built, the type first being air-launched unpowered, from a Boeing B-29 Superfortress on Jan. 19, 1946. Powered flights began in Dec. of the same year. Their designations as follows: X-1-1 (46-062), X-1-2 (46-063), X-1-3 (46-064).
They were flown by eighteen pilots from 1946 to 1951.
The first of the three X-1s was glide-tested at Pinecastle Field, FL, in early 1946. The first powered flight of the X-1 was made on Dec. 9, 1946, at Muroc Army Air Field (later redesignated Edwards Air Force Base) with Chalmers Goodlin, a Bell test pilot, at the controls. The second X-1 was used by the NACA for high speed flight research; the third aircraft was destroyed at Edwards AFB during fueling operations after completing only one unpowered glide flight.
The X-1A was similar to the X-1, except for having turbo-driven fuel pumps (instead of a system using nitrogen under pressure), a new cockpit canopy, longer fuselage and increased fuel capacity. In this aircraft a speed of Mach 2.435 was achieved on Dec. 12, 1953, and the following June an altitude of 90,000 ft. was reached. In Sept. 1954 the aircraft was given to the NACA and on July 20, 1955 it made its first and only flight for the NACA prior to being destroyed on Aug.8 1955.
The X-1B was similar to the X-1A except for having a slightly different wing. This aircraft was used for high speed research by the Air Force prior to being turned over to the NACA in Jan. 1955. This aircraft was flown by the NACA until Jan 1958.
Following the X-1B was the projected X-1C, which was cancelled while still in the mock-up stage and also the X-1D. The latter aircraft was destroyed in Aug. 1951 after being jettisoned from its B-50 carrier plane, following an explosion.
The last of the series was the X-1E. This was the second of the original X-1s fitted with new wings, turbo-driven fuel pumps and a knife-edge windscreen. This aircraft was modified and flown exclusively by the NACA. This aircraft made its first flight on Dec. 12, 1955 and was flown until Nov. 1958.
The Bell X-1-1 was equipped with a 10 percent wing and 8-percent tail, (measured as the thickness divided by the chord of the airfoil), powered with an XLR-11 rocket engine and was air-launched from under a B-29A (45-21800). The X-1-1 was glide-tested at Pinecastle Army Air Field, Orlando, Florida, beginning on January 25, 1946.
The first powered flight of the X-1-1 was made on April 11, 1946, at Muroc Army Air Field with Chalmers “Slick” Goodlin, a Bell test pilot, at the controls.
On October 14, 1947, with USAF Captain Charles “Chuck” Yeager as pilot, the X-1-1 flew faster than the speed of sound for what is generally accepted as the first supersonic flight by a piloted aircraft. Captain Yeager ignited the four-chambered XLR-11 rocket engines after being air-launched from under the bomb bay of a JTB-29A (#45-21800) at 21,000 feet. The 6,000-pound thrust ethyl alcohol/liquid oxygen burning rockets, built by Reaction Motors, Inc., pushed him up to a speed of Mach 1.06 at an altitude of 45,000 feet.
On January 5, 1949, the X-1-1 aircraft with Yeager as pilot achieved the only ground takeoff of the X-1 program. He reached just over 23,000 feet before the limited propellant was exhausted.
Captain Yeager was also the pilot when the X-1-1 reached its maximum speed, Mach 1.45. Another USAF pilot. Lt. Col. Frank Everest, Jr., was credited with taking the X-1-1 to its maximum altitude of 71,902 feet.
The X-1-1 retired on May 12, 1950 after making eighty-two glide and powered flights with ten different pilots. On August 26, 1950 the aircraft became a permanent resident of the National Air Museum, In Washington, D.C.
The X-1-2 was also equipped with the 10-percent wing and 8-percent tail, powered with an XLR-11 rocket engine and was air-launched from under a B-29A (45-21800). The aircraft made its first powered flight on December 9, 1946 with Chalmers “Slick” Goodlin at the controls. As with the X-1-1 the X-1-2 continued to investigate transonic/supersonic flight regime. NACA pilot Herbert Hoover became the first civilian to fly Mach 1, March 10, 1948.
X-1-2 flew until October 23, 1951, completing 74 glide and powered flights with nine different pilots, when it was retired to be rebuilt as X-1E.
The X-1-3 was delayed due to a turbopump development problem. It eventually fell three years behind the delivery date with its arrival to NACA High-Speed Flight Research Station at Edwards, California, in April 1951. The first glide flight was made on July 20, 1951. On November 9, 1951 following a “captive” flight the X-1-3 blew up under its own launch airplane, [EB-50A (46-006)] during static ground operations at Edwards Air Force Base, California. The B-50 was destroyed and the Bell pilot of the X-1-3, Joseph Cannon was severely burned.