List of X-planes

Bell X-1-2

The X-planes are a series of experimental United States aircraft and rockets, used to test and evaluate new technologies and aerodynamic concepts. They have an X designator, which indicates the research mission within the US system of aircraft designations.

Most of the X-planes have been operated by the National Advisory Committee for Aeronautics (NACA) or, later, the National Aeronautics and Space Administration (NASA), often in conjunction with the United States Air Force. The majority of X-plane testing has occurred at Edwards Air Force Base.^[1]

Some of the X-planes have been well publicized, while others, such as the X-16, have been developed in secrecy.^[2] The first, the Bell X-1, became well known in 1947 after it became the first aircraft to break the sound barrier in level flight.^[3] Later X-planes supported important research 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 8, 9, 11, 12, and 17 were actually missiles^{[4]:14,15,17,18,24} used to test new types of engines, and some other vehicles were un-manned (some were remotely flown, some were partially or fully autonomous).

Most X-planes are not expected to go into full-scale production; one exception was the Lockheed Martin X-35, which competed against the Boeing X-32 during the Joint Strike Fighter Program, and has entered production as the F-35.^[5]

Not all US experimental aircraft have been designated as X-planes; some received US Navy designations before 1962,^[6] while others have been known only by manufacturers' designations,^{[N 1]} non-'X'-series designations,^{[N 2]} or classified codenames.^{[N 3]}

List

List of X-planes

Type	Manufacturer	Agency	Image	Date	Role	Notes
X-1A	Bell	USAF, NACA		1946	High-speed and high-altitude flight	First aircraft to break the sound barrier in level flight. Proved aerodynamic viability of thin wing sections.[4]^:5–7
X-1B X-1C X-1D	Bell	USAF, NACA		1951	High-speed and high-altitude flight
X-1E	Bell	USAF, NACA		1955	High-speed and high-altitude flight
X-2	Bell	USAF		1952	High-speed and high-altitude flight	First aircraft to exceed Mach 3.[4]^:8
X-3 Stiletto	Douglas	USAF, NACA		1952	Highly loaded trapezoidal wing	Titanium alloy construction; Underpowered, but provided insights into inertia coupling.[4]^:9
X-4 Bantam	Northrop	USAF, NACA		1948	Transonic tailless aircraft[4]^:10
X-5	Bell	USAF, NACA		1951	variable geometry	First aircraft to fly with variable wing sweep.[4]^:11
X-6	Convair	USAF, AEC		1957	Nuclear Propulsion	Not built. The Convair NB-36H was a B-36 modified to carry a nuclear reactor and flew from 1955 to 1957.[4]^:12[7]
X-7	Lockheed	USAF, USA, USN		1951	Ramjet engines.[4]^:13
X-8 Aerobee	Aerojet	NACA, USAF, USN		1949	Upper air research[4]^:14	Later models used as sounding rockets.
X-9 Shrike	Bell	USAF		1949	Guidance and propulsion technology	Assisted development of GAM-63 Rascal missile.[4]^:15
X-10	North American	USAF		1953	SM-64 Navajo missile testbed.[4]^:16
X-11	Convair	USAF		1957	SM-65 Atlas missile testbed.[4]^:17
X-12	Convair	USAF		1957	SM-65 Atlas missile testbed.[4][4]^:18
X-13 Vertijet	Ryan	USAF, USN		1955	Vertical takeoff and landing (VTOL)	tailsitting VTOL flight.[4]^:19
X-14	Bell	USAF, NASA		1957	VTOL	Vectored thrust configuration for VTOL flight.[4]^:20
X-15	North American	USAF, NASA		1959	Hypersonic, high-altitude flight	First manned hypersonic aircraft; capable of suborbital spaceflight.[4]^:21–22
X-15 A-2	North American	USAF, NASA		1954	Hypersonic, high-altitude flight	Major Pete Knight flew the X-15 A-2 to a Mach 6.70, making it the fastest piloted flight of the X-plane program.
X-16	Bell	USAF		1954	High-altitude reconnaissance[4]^:23	"X-16" designation used to hide true purpose.[8] Cancelled and never flew.
X-17	Lockheed	USAF, USN		1956	High Mach number reentry.[4]^:24
X-18	Hiller	USAF, USN		1959	Vertical and/or short take-off and landing (V/STOL)	Evaluated the tiltwing concept for VTOL flight.[4]^:25
X-19	Curtiss-Wright	Tri-service		1963	Tandem tiltrotor VTOL[4]^:26	XC-143 designation proposed.[9]
X-20 Dyna-Soar	Boeing	USAF		1963	Reusable spaceplane	Military missions.[4]^:27 Cancelled and never built.
X-21A	Northrop	USAF		1963	Boundary layer control[4]^:28
X-22	Bell	Tri-service		1966	Quad ducted fan tiltrotor STOVL[4]^:29
X-23 PRIME	Martin Marietta	USAF		1966	Maneuvering atmospheric reentry[4]^:30	Designation never officially assigned.[10]
X-24A	Martin Marietta	USAF, NASA		1969	Low-speed lifting body[4]^:31
X-24B	Martin Marietta	USAF, NASA		1973	Low-speed lifting body[4]^:32
X-25	Bensen	USAF		1955	Commercial light autogyro for downed pilots.[4]^:33
X-26 Frigate	Schweizer	DARPA, US Army, USN		1967	Training glider for yaw-roll coupling Quiet observation aircraft[4]^:34
X-27	Lockheed	None		1971	High-performance fighter[4]^:35	Cancelled and never flew.
X-28 Sea Skimmer	Osprey	USN		1970	Low-cost aerial policing seaplane[4]^:36
X-29	Grumman	DARPA, USAF, NASA		1984	Forward-swept wing[4]^:37
X-30 NASP	Rockwell	NASA, DARPA, USAF		1993	Single stage to orbit spaceplane[4]^:38	Cancelled and never built.
X-31	Rockwell-MBB	DARPA, USAF, BdV		1990	Thrust vectoring supermaneuverability[4]^:39
X-32A	Boeing	USAF, USN, USMC, RAF		2000	Joint Strike Fighter[4]^:40–41
X-32B	Boeing	USAF, USN, RAF		2001	Joint Strike Fighter[4]^:40–41
X-33 Venture Star	Lockheed Martin	NASA		N/A	Half-scale reusable launch vehicle prototype.[4]^:42	Prototype never completed.
X-34	Orbital Sciences	NASA		N/A	Reusable unmanned spaceplane.[4]^:43	Never flew.
X-35A	Lockheed Martin	USAF, USN, USMC, RAF		2000	Joint Strike Fighter[4]^:44–45
X-35B	Lockheed Martin	USAF, USN, USMC, RAF		2001	Joint Strike Fighter[4]^:44–45
X-35C	Lockheed Martin	USAF, USN, USMC, RAF		2000	Joint Strike Fighter[4]^:44–45
X-36	McDonnell Douglas	NASA		1997	28% scale tailless fighter[4]^:46
X-37	Boeing	USAF, NASA		2010	Reusable orbital spaceplane[4]^:47	Drop test performed in 2006.
X-38	Scaled Composites	NASA		1998	Lifting body Crew Return Vehicle[4]^:48
X-39	Unknown	USAF	Classified		Future Aircraft Technology Enhancements (FATE) program.[4]^:49	Designation never officially assigned.[10]
X-40A	Boeing	USAF, NASA		1998	80% scale Space Maneuver Vehicle X-37 prototype.[4]^:50
X-41	Unknown	USAF	Classified		Maneuvering re-entry vehicle.[4]^:51
X-42	Unknown	USAF	Classified		Expendable liquid propellant upper-stage rocket.[4]^:52
X-43 Hyper-X	Micro Craft	NASA		2001	hypersonic Scramjet[4]^:53
X-44 MANTA	Lockheed Martin	USAF, NASA		N/A	F-22-based Multi-Axis No-Tail Aircraft thrust vectoring[4]^:54	Cancelled, never flew.
X-45	Boeing	DARPA, USAF		2002	Unmanned combat air vehicle (UCAV)[4]^:55
X-46	Boeing	DARPA, USN		N/A	Unmanned combat air vehicle (UCAV).[4]^:56	Naval use. Cancelled, never flew.
X-47A Pegasus X-47B	Northrop Grumman	DARPA, USN		2003	Unmanned combat air vehicle (UCAV)[4]^:57	Naval use.
X-48	Boeing	NASA		2007	Blended Wing Body (BWB)[4]^:58
X-49 Speedhawk	Piasecki	US Army		2007	Compound helicopter Vectored Thrust Ducted Propeller (VTDP) testbed.[11]
X-50 Dragonfly	Boeing	DARPA		2003	Canard Rotor/Wing[4]^:60
X-51 Waverider	Boeing	USAF		2010[12]	Hypersonic scramjet[13]
X-52	—	—	—	—	—	Number skipped to avoid confusion with Boeing B-52 Stratofortress.[10]
X-53	Boeing	NASA, USAF		2002	Active Aeroelastic Wing[14]
X-54	Gulfstream	NASA		N/A	Supersonic transport[15] in development.
X-55	Lockheed Martin	USAF		2009	Advanced Composite Cargo Aircraft (ACCA)[16]
X-56	Lockheed Martin	USAF/NASA		2012	Active flutter suppression and gust load alleviation	Part of the high-altitude, long-endurance (HALE) reconnaissance aircraft program.[17]

See also

• Experimental aircraft
• List of experimental aircraft
• List of military aircraft of the United States

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

References

1. "X-Planes Experimental Aircraft". Federation of American Scientists. Retrieved 2012-06-01.
2. Miller 2001, p. 209
3. First Generation X-1 (fact sheet), Dryden: NASA, retrieved May 8, 2010.
4. Jenkins, Landis and Miller 2003
5. A history of the Joint Strike Fighter Program, UK: Martin-Baker, January 2010.
6. "D-558-I" NASA Dryden Fact Sheets. NASA. Accessed May 8, 2010.
7. Miller, J. The X-Planes, Speciality Press, 1983.
8. "X-16". Global security, accessed 11 May 2010.
9. Baugher 2007
10. Parsch 2009, "Missing Designations"
11. Parsch 2009, "DOD 4120.15-L"
12. "X-51 Waverider makes historic hypersonic flight". US Air Force Public Affairs. 26 May 2010. Retrieved 27 May 2010.
13. "X-51 Scramjet Engine Demonstrator - WaveRider" globalsecurity.org. Accessed 2010-05-11.
14. Jordan 2006
15. 412015-L
16. Kaufman 2009
17. Norris 2012

Bibliography

• Baugher, Joe (2007). "Cargo Aircraft Designations". Retrieved 11 May 2010.
• Jenkins, Dennis R.; Tony Landis; Jay Miller (June 2003). American X-Vehicles: An Inventory—X-1 to X-50 (NASA Special Publication; PDF). Monographs in Aerospace History. No. 31 (Centennial of Flight ed.). Washington, DC: NASA History Office. SP-2003-4531. Retrieved 5 April 2010.
• Jordan, Holly (2006). "Active Aeroelastic Wing flight research vehicle receives X-53 designation". Wright-Patterson Air Force Base. Retrieved 2010-05-11.
• Kaufman, Derek (2009). "Advanced Composite Cargo Aircraft gets X-plane designation". United States Air Force. Retrieved 2010-05-11.
• Miller, Jay (2001). The X-Planes: X-1 to X-45 (third ed.). Motorbooks International. ISBN 1-85780-109-1.
• Parsch, Andreas (November 2009). ""Missing" USAF/DOD Aircraft Designations". designation-systems.net. Retrieved 2010-05-11.
• Parsch, Andreas (November 2009). "DOD 4120.15-L - Addendum, MDS Designators allocated after 19 August 1998 (until September 2009)". designation-Systems.Net. Retrieved 2010-05-11.
• Norris, Guy (February 2012). "USAF Reveals Latest X-Plane: X-56A". Aviation Week and Space Technology. Retrieved 2012-02-11.

External links

• Early X-planes
• X-15 Videos by NASA