List of X-planes

The X-planes are a series of experimental United States airplanes and helicopters (and some rockets) used for the testing and evaluation of new technologies and aerodynamic concepts. Some members of the series have been well publicised, while others, such as the X-16 project, have been developed in secrecy.[1]

The first of the X-planes, the Bell X-1, became well known as, in 1947, it was the first aircraft to break the sound barrier in level flight.[2] Later X-planes yielded important research results in a multitude of aerodynamic and technical fields, but only the North American X-15 rocket plane of the early 1960s achieved comparable fame to that of the X-1. X-planes 7 through 12 were actually missiles[3] (used to test new types of engines), and some other vehicles were un-piloted (some were remotely flown, some were full-on drones). Most X-planes are not expected to go into full-scale production, however an exception to the rule was the Lockheed Martin X-35, which competed against the Boeing X-32 in a fly-off as part of the Joint Strike Fighter Program, and has entered into production as the F-35.[4]

Most of the X-planes have been operated by the National Advisory Committee for Aeronautics (NACA) or, later, the National Aeronautics and Space Agency (NASA), often in conjunction with the United States Air Force. However, not all US experimental aircraft have been designated in the X-plane series; some received U.S. Navy designations prior to 1962,[5] while others have been known only by manufacturers' designations,[N 1] non-'X'-series designations,[N 2] or classified codenames.[N 3]

Contents

List of X-planes

Name Manufacturer
Agency		 Image Maiden flight Purpose and Notes
X-1 Bell Aircraft
USAF, NACA		 January 19, 1946 High-speed and high-altitude testing.
First aircraft to break the sound barrier.
Proved aerodynamic viability of thin wing sections.[6]
X-2
"Starbuster"		 Bell Aircraft
USAF		 June 27, 1952 High-speed and high-altitude testing.
First aircraft to exceed Mach 3.[7]
X-3
Stiletto		 Douglas Aircraft
USAF, NACA		 October 27, 1952 Titanium alloy construction; low aspect ratio wings.
Planned to test long-duration high-speed flight.
Incapable of reaching design speed, but Provided insights into inertia coupling.[8]
X-4
Bantam		 Northrop
USAF, NACA		 December 15, 1948 Evaluated handling characteristics of tailless aircraft in the transonic speed region.[9]
X-5 Bell Aircraft
USAF, NACA		 June 20, 1951 First aircraft to fly with variable geometry wings.[10]
X-6 Convair
USAF, AEC		 Not flown Modified Convair B-36 for study of Aircraft Nuclear Propulsion; not built.
NB-36H testbed tested reactor.[11]
X-7
"Flying Stove Pipe"		 Lockheed
Tri-service		 April 1951 High-speed testbed for ramjet engines.[12]
X-8
Aerobee		 Aerojet
NACA, USAF, USN		 Upper air research vehicle and sounding rocket.[13]
X-9
Shrike		 Bell Aircraft
USAF		 April 1949 Guidance and propulsion technology testbed.
Assisted development of GAM-63 Rascal missile.[14]
X-10 North American Aviation
USAF		 October 13, 1953 Testbed for SM-64 Navajo missile.[15]
X-11 Convair
USAF		 June 11, 1957 Testbed for SM-65 Atlas missile.[16]
X-12 Convair
USAF		 July, 1958 Advanced testbed for SM-65 Atlas missile.[17]
X-13
Vertijet		 Ryan Aeronautical
USAF, USN		 December 10, 1955 Vertical takeoff and landing (VTOL) testbed.
Evaluated tailsitting configuration for VTOL flight.[18]
X-14 Bell Aircraft
USAF, NASA		 February 19, 1957 VTOL testbed.
Examined the vectored thrust configuration for VTOL flight.[19]
X-15 North American Aviation
USAF, NASA		 June 8, 1959 Hypersonic (Mach 6), high-altitude (350,000 feet (110,000 m)) testing.
First manned hypersonic aircraft; capable of suborbital spaceflight.[20]
X-16 Bell Aircraft
USAF		 Never flew High-altitude reconnaissance aircraft project.[21]
"X-16" designation used as cover story.[22]
X-17 Lockheed
USAF, USN		 April 1956 Tested the effects of high Mach number reentry.[23]
X-18 Hiller Aircraft
USAF, USN		 November 24, 1959 VTOL/Short take-off and vertical landing (STOVL) testbed.
Evaluated the tiltwing concept for VTOL flight.[24]
X-19 Curtiss-Wright
Tri-service		 November 1963 Tandem tiltrotor VTOL transport testbed.[25]
XC-143 designation proposed.[26]
X-20
Dyna-Soar		 Boeing
USAF		 Never built Reusable spaceplane for military missions.[27]
X-21 Northrop
USAF		 April 18, 1963 Boundary layer control testbed.[28]
X-22 Bell Aircraft
Tri-service		 March 17, 1966 Quad ducted fan tiltrotor STOVL testbed.[29]
X-23
PRIME		 Martin Marietta
USAF		 December 21, 1966 Manuvering atmospheric reentry effects testbed.[30]
Note: Designation never officially assigned.[31]
X-24 Martin Marietta
USAF, NASA
August 1, 1973 Low-speed lifting body handling testbed.
Lifting body aerodynamic shape trials.[32]
X-25 Benson
USAF		 December 6, 1955 Light autogyro for emergency use by downed pilots.[33]
X-26
Frigate		 Schweizer
DARPA, US Army, USN
1967
Training glider for yaw-roll coupling
Quiet observation aircraft testbed.[34]
X-27 Lockheed Never flew High performance fighter prototype.[35]
X-28
Sea Skimmer		 Osprey Aircraft
USN		 August 12, 1970 Inexpensive aerial policing seaplane testbed.[36]
X-29 Grumman
DARPA, USAF, NASA		 1984 Forward-swept wing testbed.[37]
X-30
NASP		 Rockwell
NASA, DARPA, USAF		 Never built Single stage to orbit spaceplane prototype.[38]
X-31 Rockwell
DARPA, USAF, BdV		 1990 Thrust vectoring supermaneuverability testbed.
ESTOL testbed.[39]
X-32 Boeing
USAF, USN, RAF		 September 2000 Joint Strike Fighter prototype.[40]
X-33
Venture Star		 Lockheed Martin
NASA		 Prototype never completed Half-scale reusable launch vehicle prototype.[41]
X-34 Orbital Sciences
NASA		 Never flew Reusable unmanned spaceplane testbed.[42]
X-35 Lockheed Martin
USAF, USN, RAF		 2000 Joint Strike Fighter prototype.[43]
X-36 McDonnell Douglas/Boeing
NASA		 May 17, 1997 28% scale tailless fighter testbed.[44]
X-37 Boeing
USAF, NASA		 April 7, 2006 (drop test)
April 22, 2010 (orbital flight)		 Reusable orbital spaceplane.[45]
X-38 Scaled Composites
NASA		 1999 Lifting body Crew Return Vehicle demonstrator.[46]
X-39 Unknown
USAF		 Classified Unknown Future Aircraft Technology Enhancements (FATE) program.[47]
Note: Designation never officially assigned.[31]
X-40 Boeing
USAF, NASA		 August 11, 1998 80% scale Space Maneuver Vehicle testbed.
X-37 prototype.[48]
X-41 Unknown
USAF		 Classified Unknown Maneuvering re-entry vehicle.[49]
X-42 Unknown
USAF		 Classified Unknown Expendable liquid propellant upper stage rocket.[50]
X-43
Hyper-X		 Microcraft
NASA		 June 2, 2001 Scramjet hypersonic testbed.[51]
X-44
MANTA		 Lockheed Martin
USAF, NASA		 Cancelled F-22-based Multi-Axis No-Tail Aircraft thrust vectoring testbed.[52]
X-45 Boeing
DARPA, USAF
May 22, 2002 Unmanned combat air vehicle (UCAV) demonstrator.[53]
X-46 Boeing
DARPA, USN		 Cancelled Naval UCAV demonstrator.[54]
X-47A Pegasus
X-47B		 Northrop Grumman
DARPA, USN		 February 23, 2003 Naval UCAV demonstrator.[55]
X-48 Boeing
NASA		 July 20, 2007 Blended Wing Body (BWB) testbed.[56]
X-49
Speedhawk		 Piasecki Aircraft
US Army		 July 29, 2007 Compound helicopter
Vectored Thrust Ducted Propeller (VTDP) testbed.[57]
X-50
Dragonfly		 Boeing
DARPA		 24 November 2003 Canard Rotor/Wing testbed.[58]
X-51
Waverider		 Boeing
USAF		 26 May 2010[59] Hypersonic scramjet demonstrator.[60]
X-52 Number skipped to avoid confusion with B-52.[31]
X-53 Boeing Phantom Works
NASA, USAF		 November 2002 Active Aeroelastic Wing testbed.[61]
X-54 Gulfstream Aerospace
NASA		 Future Supersonic transport testbed.[57]
X-55 Lockheed Martin Skunk Works
USAF		 June 2, 2009 Advanced Composite Cargo Aircraft (ACCA).
Molded composite fuselage and empennage testbed.[62]

See also

References

Notes
  1. ^ For example, the Piasecki PA-97
  2. ^ For example, the NASA AD-1 and Bell XV-15
  3. ^ For example, the Northrop Tacit Blue
Citations
  1. ^ Miller 2001, p. 209
  2. ^ "First Generation X-1". NASA Dryden Fact Sheets. NASA. Accessed May 8 2010.
  3. ^ Miller 2001
  4. ^ A history of the Joint Strike Fighter Program, Martin-Baker. Retrieved January 2010
  5. ^ "D-558-I" NASA Dryden Fact Sheets. NASA. Accessed May 8 2010.
  6. ^ Jenkins, Landis and Miller 2003, pp. 5–7.
  7. ^ Jenkins, Landis and Miller 2003, p. 8.
  8. ^ Jenkins, Landis and Miller 2003, p. 9.
  9. ^ Jenkins, Landis and Miller 2003, p. 10.
  10. ^ Jenkins, Landis and Miller 2003, p. 11.
  11. ^ Jenkins, Landis and Miller 2003, p. 12.
  12. ^ Jenkins, Landis and Miller 2003, p. 13.
  13. ^ Jenkins, Landis and Miller 2003, p. 14.
  14. ^ Jenkins, Landis and Miller 2003, p. 15.
  15. ^ Jenkins, Landis and Miller 2003, p. 16.
  16. ^ Jenkins, Landis and Miller 2003, p. 17.
  17. ^ Jenkins, Landis and Miller 2003, p. 18.
  18. ^ Jenkins, Landis and Miller 2003, p. 19.
  19. ^ Jenkins, Landis and Miller 2003, p. 20.
  20. ^ Jenkins, Landis and Miller 2003, pp. 21–22.
  21. ^ Jenkins, Landis and Miller 2003, p. 23.
  22. ^ "X-16". globalsecurity.org, accessed 11 May 2010.
  23. ^ Jenkins, Landis and Miller 2003, p. 24.
  24. ^ Jenkins, Landis and Miller 2003, p. 25.
  25. ^ Jenkins, Landis and Miller 2003, p. 26.
  26. ^ Baugher 2007
  27. ^ Jenkins, Landis and Miller 2003, p. 27.
  28. ^ Jenkins, Landis and Miller 2003, p. 28.
  29. ^ Jenkins, Landis and Miller 2003, p. 29.
  30. ^ Jenkins, Landis and Miller 2003, p. 30.
  31. ^ a b c Parsch 2009, "Missing Designations"
  32. ^ Jenkins, Landis and Miller 2003, pp. 31–32.
  33. ^ Jenkins, Landis and Miller 2003, p. 33.
  34. ^ Jenkins, Landis and Miller 2003, p. 34.
  35. ^ Jenkins, Landis and Miller 2003, p. 35.
  36. ^ Jenkins, Landis and Miller 2003, p. 36.
  37. ^ Jenkins, Landis and Miller 2003, p. 37.
  38. ^ Jenkins, Landis and Miller 2003, p. 38.
  39. ^ Jenkins, Landis and Miller 2003, p. 39.
  40. ^ Jenkins, Landis and Miller 2003, pp. 40–41.
  41. ^ Jenkins, Landis and Miller 2003, p. 42.
  42. ^ Jenkins, Landis and Miller 2003, p. 43.
  43. ^ Jenkins, Landis and Miller 2003, p. 44–45.
  44. ^ Jenkins, Landis and Miller 2003, p. 46.
  45. ^ Jenkins, Landis and Miller 2003, p. 47.
  46. ^ Jenkins, Landis and Miller 2003, p. 48.
  47. ^ Jenkins, Landis and Miller 2003, p. 49.
  48. ^ Jenkins, Landis and Miller 2003, p. 50.
  49. ^ Jenkins, Landis and Miller 2003, p. 51.
  50. ^ Jenkins, Landis and Miller 2003, p. 52.
  51. ^ Jenkins, Landis and Miller 2003, p. 53.
  52. ^ Jenkins, Landis and Miller 2003, p. 54.
  53. ^ Jenkins, Landis and Miller 2003, p. 55.
  54. ^ Jenkins, Landis and Miller 2003, p. 56.
  55. ^ Jenkins, Landis and Miller 2003, p. 57.
  56. ^ Jenkins, Landis and Miller 2003, p. 58.
  57. ^ a b Parsch 2009, "DOD 4120.15-L"
  58. ^ Jenkins, Landis and Miller 2003, p. 60.
  59. ^ "X-51 Waverider makes historic hypersonic flight". US AIr Force Public Affairs. 26 May 2010. http://www.af.mil/news/story.asp?id=123206525. Retrieved 27 May 2010. 
  60. ^ "X-51 Scramjet Engine Demonstrator - WaveRider" globalsecurity.org. Accessed 2010-05-11.
  61. ^ Jordan 2006
  62. ^ Kaufman 2009
Bibliography

External links

USAF/Joint Service experimental aircraft (X-plane) designations since 1941
1–25

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-24A · X-24B · X-25
26–50

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-47A / X-47B · X-48 · X-49 · X-50
50–

X-51 · X-521 · X-53 · X-54 · X-55
See also
1 Unused, to avoid confusion with the B-52.
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