Bell X-1

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For the article about the Irish band, see Bell X1.
Bell X-1
X-1 #46-062, nicknamed "Glamorous Glennis"
Type rocket plane
Manufacturer Bell Aircraft Corporation
Maiden flight 1946-01-19
Status Retired
Primary users USAF
NACA

The Bell X-1, originally designated XS-1, was a joint NACA-U.S. Army Air Force supersonic research project and the first aircraft to exceed the speed of sound in controlled, level flight. It was the first of the so-called X-planes, an American series of experimental aircraft designated for testing of new technologies and usually kept highly secret.

Contents

[edit] XS-1

[edit] Program History

X-1 at the Smithsonian
Enlarge
X-1 at the Smithsonian

On 16 March 1946 the United States Army Air Forces' Flight Test Division and the National Advisory Committee for Aeronautics (NACA) (now NASA) contracted Bell Aircraft to build three XS-1 (for "Experimental, Supersonic", later X-1) aircraft to obtain flight data on conditions in the transonic speed range.[1] The XS-1 was the first high-speed aircraft built purely for aviation research purposes and was never intended for production.

Bell Aircraft Chief test pilot, Jack Woolams became the first to fly the XS-1, in a glide flight over Pinecastle Army Airfield, in Florida, on 25 January, 1946. Woolams would complete nine additional glide flights over Pinecastle before March 1946, when the #1 aircraft was returned to Bell for modifications in anticipation of the powered flight tests, planned for Muroc Army Air Field (now Edwards Air Force Base) in California.[2] Following Wollams' death on 30 August, 1946, Chalmers "Slick" Goodlin was the primary Bell Aircraft test pilot of X-1-1. He made twenty-six successful flights in both of the X-1 aircraft from September 1946 until June 1947. The Army Air Force was unhappy with the cautious pace of flight envelope expansion and Bell Aircraft's flight test contract for aircraft #46-062 was terminated and was taken over by the Army Air Force Flight Test Division on 24 June after months of negotiation. Goodlin had demanded a $150,000 bonus for breaking the sound barrier.[3][4][5] Flight tests of the X-1-2 (serial number 46-063) would be conducted by NACA to provide design data for later production high-performance aircraft.

On October 14, 1947, the tests culminated in the first piloted flight faster than Mach 1.0, piloted by Air Force Captain Charles "Chuck" Yeager in aircraft #46-062, which he had christened ‘Glamorous Glennis’, after his wife. The rocket-powered aircraft was launched from the belly of a specially modified B-29 and glided to a landing on a runway. XS-1 flight number 50 is the first one where the X-1 recorded supersonic flight, at Mach 1.06 peak speed; however, Yeager and many other personnel record the possibility that Flight #49 (also with Yeager piloting), which reached a top recorded speed of Mach 0.997, may have in fact passed the Sound Barrier. (The measurements were not accurate to three significant figures and no sonic boom was recorded for that flight.)

XLR-11 rocket engine
Enlarge
XLR-11 rocket engine

As a result of the X-1's initial supersonic flight, the National Aviation Association voted its 1948 Collier Trophy to be shared by the three main participants in the program. Honored at the White House by President Truman were Larry Bell for Bell Aircraft, Captain Yeager for piloting the flights, and John Stack of NACA for the NACA contributions. Years later, Yeager reported that his father, a staunch Republican, refused to shake hands with President Truman (a Democrat).

[edit] Disposition

Aircraft #46-062 is currently on display in the Milestones of Flight gallery of the National Air and Space Museum in Washington, DC, alongside the Spirit of St. Louis and SpaceShipOne. Aircraft #46-063, now the X-1E, is on display in front of the NASA Dryden Flight Research Center headquarters building. Aircraft #46-064 was destroyed 9 November, 1951, in a ground fire following a captive flight test, after completing only a single glide flight (20 July, 1951.[6]

[edit] Legacy

The research techniques used in the X-1 program became the pattern for all subsequent X-craft projects. The NACA X-1 procedures and personnel also helped lay the foundation of America's space program in the 1960s. The X-1 project defined and solidified the post-war cooperative union between U.S. military needs, industrial capabilities, and research facilities. The flight data collected by the NACA in the X-1 tests then provided a basis for American aviation supremacy in the latter half of the 20th century.

It should be noted that the intentions of the X-1 experiments were not to exceed the speed of sound in of itself, but to determine if, and then demonstrate that, controlled, sustained flight was possible at supersonic speeds. In the above claims, the sound barrier was supposedly breached by diving aircraft and it would be impossible there to determine if aerodynamic lift could be maintained at those speeds.

Later variants of the X-1 were built to test different aspects of supersonic flight; one of these, the X-1A, with Yeager at the controls, inadvertently demonstrated a very dangerous characteristic of fast (Mach 2-plus) supersonic flight: inertia coupling. Only Yeager's skills as an aviator prevented him from dying that day; later Mel Apt would die testing the Bell X-2 under similar circumstances.

[edit] Controversies

It has been suggested that this article or section be merged with Sound barrier. (Discuss)

Some claims have been voiced that the overall design of the X-1 was heavily based on the British designed Miles M.52 jet. The Miles M.52 was cancelled by the British government just months away from the first scheduled test flight, and all technical data from the project was transferred to Bell-- however, almost all of the design work on the X-1 had been completed by that time. The one critical piece of design transferred from the M.52 to the XS-1 was the all-moving tail,[citation needed] key to supersonic flight control. Later tests show that the Miles M.52 would probably have broken the sound barrier if allowed to fly.

The German pilot Hans Guido Mutke claimed to be the first person to break the sound barrier, on April 9, 1945 in a Messerschmitt Me 262, but this claim is disputed. The mysterious 702 mph Me-163B by Dittmar flight is wrapped in mystery and has no Mach number associated with it. Many also contend that George Welch broke the barrier on October 1, 1947 in his XP-86 Sabre during a dive, just two weeks before the X-1. Full confirmation of Welch's achievement is not available, although it is very likely that he exceeded Mach 1 more than once sometime in the October - November, 1947 period, and perhaps as early as October 1.

Three view diagram

General characteristics

  • Crew: 1
  • Length: 30 ft 11 in (9.4 m)
  • Wingspan: 28 ft 0 in (8.5 m)
  • Height: 10 ft 10 in (3.3 m)
  • Wing area: 130 ft² (12 m²)
  • Empty weight: 7,000 lb (3,175 kg)
  • Loaded weight: 12,225 lb (5,545 kg)
  • Max takeoff weight: 12,250 lb (5,557 kg)
  • Powerplant: × Reaction Motors XLR-11-RM3 rocket, 6,000 lbf (26.7 kN) each

Performance

[edit] X-1A

Ordered by the Air Force on 2 April 1948, the X-1A (serial 48-1384) was intended to investigate aerodynamic phenomena at speeds above Mach 2 and altitudes greater than 90,000 feet, specifically focusing on dynamic stability and air loads. The aircraft first flew, unpowered, on 14 February 1953 at Edwards AFB, with the first powered flight on 21 February. Both flights were piloted by Bell test pilot Jean Ziegler. The aircraft was transferred to NACA in September 1954. Following modifications, including the installation of an ejection seat, the aircraft was lost on 8 August 1955 while being prepared for launch from the RB-50 mothership.[7]

Data from [8]

General characteristics

Performance

[edit] X-1B

Data from [9]

General characteristics

Performance

[edit] X-1C

The X-1C was intended to test armaments and munitions in the high transonic and supersonic flight regimes. It was canceled while still in the mock-up stage, as the birth of transonic and supersonic-capable aircraft like the North American F-86 Sabre and the North American F-100 Super Sabre eliminated the need for a dedicated experimental test platform. [10]

[edit] X-1D

Data from [11]

General characteristics

Performance

[edit] X-1E

The X-1E resulted from a significant reconstruction of the X-1-2 (s/n 46-063) in order to pursue the goals originally set out for the X-1D and X-1-3, both lost in explosions in 1951.

The X-1E, christened ‘Little Joe’ with Joe Walker.
Enlarge
The X-1E, christened ‘Little Joe’ with Joe Walker.

The changes included:

  • A turbopump fuel feed system, which eliminated the high-pressure nitrogen fuel system used in '062 and '063. (Concerns about metal fatigue in the nitrogen fuel system resulted in the grounding of the X-1-2 after its 54th flight in its original configuration.)[12].
  • A re-profiled super-thin wing (3⅜ inches at the root), based on the X-3 Stiletto wing profile, enabling the X-1E to reach Mach 2.
  • A 'knife-edge' windscreen replaced the original greenhouse glazing, an upward-opening canopy replaced the fuselage-side hatch and facilitated the inclusion of an ejection seat.
  • The addition of 200 pressure ports for aerodynamic data, and 343 strain gages to measure structural loads and aerodynamic heating along the wing and fuselage. [13]

[edit] Operational History

The X-1E first flew on 15 December 1955, a glide flight under the controls of USAF test-pilot Joe Walker. Walker left the X-1E program in 1958, after 21 flights, attaining a maximum speed of Mach 2.21. NACA research pilot John B. McKay took his place in September 1958, completing five flights in pursuit of Mach 3 before the X-1E was permanently grounded following its 26th overall flight, in November 1958, due to the discovery of structural cracks in the fuel tank wall.

[edit] Disposition

The X-1E is permanently on display in front of the NASA Dryden Flight Research Center headquarters building, at Edwards AFB.

[edit] X-1B

Data from [14]

General characteristics

Performance

[edit] References

  1. ^ Miller, Jay. (2001). The X-Planes: X-1 to X-45, Hinckley, UK: Midland. ISBN 1-85780-109-1.
  2. ^ http://www.cebudanderson.com/initialglideflights.htm
  3. ^ Yeager, Chuck and Janos, Leo. Yeager: An Autobiography. Page 121 (paperback). New York: Bantam Books, 1986. ISBN 0-553-25674-2.
  4. ^ Wolfe, Tom, The Right Stuff. Pages 52-53 (hardcover). Farrar-Straus-Giroux, New York. 1979. ISBN 0374250332.
  5. ^ http://www.cebudanderson.com/aturningpoint.htm
  6. ^ Miller, Jay. (2001). The X-Planes: X-1 to X-45, Hinckley, UK: Midland. ISBN 1-85780-109-1.
  7. ^ Miller, Jay. (2001). The X-Planes: X-1 to X-45, Hinckley, UK: Midland. ISBN 1-85780-109-1.
  8. ^ Miller, Jay. (2001). The X-Planes: X-1 to X-45, Hinckley, UK: Midland. ISBN 1-85780-109-1.
  9. ^ Miller, Jay. (2001). The X-Planes: X-1 to X-45, Hinckley, UK: Midland. ISBN 1-85780-109-1.
  10. ^ http://www1.dfrc.nasa.gov/gallery/photo/X-1A/HTML/E-24911.html
  11. ^ Miller, Jay. (2001). The X-Planes: X-1 to X-45, Hinckley, UK: Midland. ISBN 1-85780-109-1.
  12. ^ http://www.nasa.gov/centers/dryden/news/FactSheets/FS-083-DFRC.html
  13. ^ http://www.nasa.gov/centers/dryden/news/FactSheets/FS-083-DFRC.html
  14. ^ Miller, Jay. (2001). The X-Planes: X-1 to X-45, Hinckley, UK: Midland. ISBN 1-85780-109-1.

[edit] External links

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[edit] See also

v • d • e
American X-planes

X-1 · X-2 · X-3 · X-4 · X-5 · X-6 · X-7 · X-8 · X-9 · X-10 · X-11 · X-12 · X-13 · X-14 · X-15 · X-16 · X-17 · X-18 · X-19 · X-20 · X-21 · X-22 · X-23 · X-24 · X-25 · X-26 · X-27 · X-28 · X-29 · X-30 · X-31 · X-32 · X-33 · X-34 · X-35 · X-36 · X-37 · X-38 · X-39 · X-40 · X-41 · X-42 · X-43 · X-44 · X-45 · X-46 · X-47 · X-48 · X-49 · X-50 · X-51

See also List of experimental aircraft

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