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list of X-planes

{{Short description|Series of experimental US aircraft and rockets}}

{{About|the US Experimental planes|the simulator|X-Plane (simulator)}}

{{Use dmy dates|date=May 2023}}

{{Use American English|date=May 2023}}

File:BellX-1.jpeg

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 within the US system of aircraft designations, which denotes the experimental research mission.

Not all US experimental aircraft have been designated as X-planes; some received US Navy designations before 1962,[http://www.nasa.gov/centers/dryden/news/FactSheets/FS-036-DFRC.html "D-558-I"] NASA Dryden Fact Sheets. NASA. Accessed May 8, 2010. while others have been known only by manufacturers' designations,{{#tag:ref|For example, the Piasecki PA-97|group= N}} non-'X'-series designations,{{#tag:ref|For example, the NASA AD-1 and Bell XV-15|group=N}} or classified codenames.{{#tag:ref|For example, the Northrop Tacit Blue|group=N}} This list only includes the designated X-planes.

History

The X-planes concept officially came into being in 1944, as a joint programme involving the National Advisory Committee for Aeronautics (NACA), the US Navy (USN) and the US Army Air Forces (USAAF), in order to pursue research into high-speed aircraft.Miller 1983, p.9. NACA later became the National Aeronautics and Space Administration (NASA) and the USAAF became the United States Air Force (USAF). Other organizations such as the Defence Advanced Research Projects Agency (DARPA) and the US Marine Corps (USMC) have also since sponsored X-plane projects.

The first experimental aircraft specification, for a transonic rocket plane, was placed in 1945, and the first operational flight of an X-plane took place when the Bell X-1 made its first powered flight nearly three years later at Muroc Air Force Base, California, now known as Edwards Air Force Base.Miller 1983, pp.15-17. The majority of X-plane testing has since taken place there.{{Cite web | title =X-Planes Experimental Aircraft | publisher =Federation of American Scientists |url= http://www.fas.org/programs/ssp/man/uswpns/air/xplanes/xplanes.html |access-date= 2012-06-01}}

X-planes have since accomplished many aviation "firsts" including breaking speed and altitude barriers, varying wing sweep in flight, implementing exotic alloys and propulsion innovations, and many more.

New X-planes appeared fairly regularly for many years until the flow temporarily stopped in the early 1970s. A series of experimental hypersonic projects, including an advanced version of the Martin Marietta X-24 lifting body, were turned down. Eventually issues with the Rockwell HiMAT advanced UAV led to a crewed X-plane with forward sweep, the Grumman X-29, which flew in 1984.Miller 1983, p.13.

Some of the X-planes have been well publicized, while others, such as the X-16, have been developed in secrecy.Miller 2001, p. 209 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.{{Citation | url = http://www.nasa.gov/centers/dryden/news/FactSheets/FS-085-DFRC.html | title = First Generation X-1 | publisher = NASA | place = Dryden | type=fact sheet | access-date = May 8, 2010}}. 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.{{citation needed|date=March 2016|reason=the fame comparison looks suspiciously like an editorial value judgement}} X-planes 8, 9, 11, 12, and 17 were actually missiles{{sfn|Jenkins|Landis|Miller| 2003|p=14,15,17,18,24}} used to test new types of engines, and some other vehicles were unoccupied or UAVs (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 Lightning II.{{Citation|url=http://www.martin-baker.co.uk/getdoc/d25952ab-5881-4999-8593-6f7f196c8770/a_history_of_the_joint_strike_fighter_programme.aspx |title=A history of the Joint Strike Fighter Program |publisher=Martin-Baker |place=UK |date=January 2010 |url-status=dead |archive-url=https://web.archive.org/web/20101230143911/http://www.martin-baker.co.uk/getdoc/d25952ab-5881-4999-8593-6f7f196c8770/a_history_of_the_joint_strike_fighter_programme.aspx |archive-date=2010-12-30 }}.

List

In the list, the date is that of the first flight, or of cancellation if it never flew.

class="wikitable sortable"

|+ List of X-planes

class="unsortable" style="width:120px;" | Image

! Type

! Manufacturer

! Agency

! Date

! Role

! class="unsortable" | Notes

120px

| X-1

| 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.{{sfn|Jenkins|Landis|Miller| 2003|p=5–7}}

120px

| X-1A X-1B X-1C X-1D

| Bell

| USAF, NACA

| 1951

| High-speed and high-altitude flight

|

120px

| X-1E

| Bell

| USAF, NACA

| 1955

| High-speed and high-altitude flight

|

120px

| X-2

| Bell

| USAF

| 1952

| High-speed and high-altitude flight

| First aircraft to exceed Mach 3.{{sfn|Jenkins|Landis|Miller| 2003|p=8}}

120px

| X-3 Stiletto

| Douglas

| USAF, NACA

| 1952

| Highly loaded trapezoidal wing

| Titanium alloy construction; Underpowered, but provided insights into inertia coupling.{{sfn|Jenkins|Landis|Miller| 2003|p=9}}

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| X-4 Bantam

| Northrop

| USAF, NACA

| 1948

| Transonic tailless aircraft{{sfn|Jenkins|Landis|Miller| 2003|p=10}}

|

120px

| X-5

| Bell

| USAF, NACA

| 1951

| variable geometry

| First aircraft to fly with variable wing sweep.{{sfn|Jenkins|Landis|Miller| 2003|p=11}}

120px

| X-6

| Convair

| USAF, AEC

| 1957

| Nuclear Propulsion

| Not built. The Convair NB-36H experiment, a B-36 modified to carry (but not powered by) a nuclear reactor, flew from 1955 to 1957.{{sfn|Jenkins|Landis|Miller| 2003|p=12}}Miller 1983.

120px

| X-7

| Lockheed

| USAF, USA, USN

| 1951

| Ramjet engines.{{sfn|Jenkins|Landis|Miller| 2003|p=13}}

|

120px

| X-8 Aerobee

| Aerojet

| NACA, USAF, USN

| 1949

| Upper air research{{sfn|Jenkins|Landis|Miller| 2003|p=14}}

| Later models used as sounding rockets.

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| X-9 Shrike

| Bell

| USAF

| 1949

| Guidance and propulsion technology

| Assisted development of GAM-63 Rascal missile.{{sfn|Jenkins|Landis|Miller| 2003|p=15}}

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| X-10

| North American

| USAF

| 1953

| SM-64 Navajo missile testbed.{{sfn|Jenkins|Landis|Miller| 2003|p=16}}

|

| X-11

| Convair

| USAF

| 1953

| Proposed SM-65 Atlas missile testbed.{{sfn|Jenkins|Landis|Miller| 2003|p=17}}

|

| X-12

| Convair

| USAF

| 1953

| Proposed SM-65 Atlas missile testbed.{{sfn|Jenkins|Landis|Miller| 2003|p=18}}

|

120px

| X-13 Vertijet

| Ryan

| USAF, USN

| 1955

| Vertical takeoff and landing (VTOL)

| tailsitting VTOL flight.{{sfn|Jenkins|Landis|Miller| 2003|p=19}}

120px

| X-14

| Bell

| USAF, NASA

| 1957

| VTOL

| Vectored thrust configuration for VTOL flight.{{sfn|Jenkins|Landis|Miller| 2003|p=20}}

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| X-15

| North American

| USAF, NASA

| 1959

| Hypersonic, high-altitude flight

| First crewed hypersonic aircraft; capable of suborbital spaceflight.{{sfn|Jenkins|Landis|Miller| 2003|p=21–22}}

120px

| X-15A-2

| North American

| USAF, NASA

| 1964

| Hypersonic, high-altitude flight

| Major Pete Knight flew the X-15A-2 to a Mach 6.70, making it the fastest piloted flight of the X-plane program.

120px

| X-16

| Bell

| USAF

| 1954

| High-altitude reconnaissance{{sfn|Jenkins|Landis|Miller| 2003|p=23}}

| "X-16" designation used to hide true purpose.[http://www.globalsecurity.org/military/systems/aircraft/x-16.htm "X-16"]. Global security, accessed 11 May 2010. Canceled and never flew.

120px

| X-17

| Lockheed

| USAF, USN

| 1956

| High Mach number reentry.{{sfn|Jenkins|Landis|Miller| 2003|p=24}}

|

120px

| X-18

| Hiller

| USAF, USN

| 1959

| Vertical and/or short take-off and landing (V/STOL)

| Evaluated the tiltwing concept for VTOL flight.{{sfn|Jenkins|Landis|Miller| 2003|p=25}}

120px

| X-19

| Curtiss-Wright

| Tri-service

| 1963

| Tandem tiltrotor VTOL{{sfn|Jenkins|Landis|Miller| 2003|p=26}}

| XC-143 designation requested but turned down.

120px

| X-20 Dyna-Soar

| Boeing

| USAF

| 1963

| Reusable spaceplane

| Intended for military missions.{{sfn|Jenkins|Landis|Miller| 2003|p=27}} Canceled and never built.

120px

| X-21A

| Northrop

| USAF

| 1963

| Boundary layer control{{sfn|Jenkins|Landis|Miller| 2003|p=28}}

|

120px

| X-22

| Bell

| Tri-service

| 1966

| Quad ducted fan tiltrotor STOVL{{sfn|Jenkins|Landis|Miller| 2003|p=29}}

|

120px

| X-23 PRIME

| Martin Marietta

| USAF

| 1966

| Maneuvering atmospheric reentry{{sfn|Jenkins|Landis|Miller| 2003|p=30}}

| Designation never officially assigned.Parsch 2024, "Missing Designations"

120px

| X-24A

| Martin Marietta

| USAF, NASA

| 1969

| Low-speed lifting body{{sfn|Jenkins|Landis|Miller| 2003|p=31}}

|

120px

| X-24B

| Martin Marietta

| USAF, NASA

| 1973

| Low-speed lifting body{{sfn|Jenkins|Landis|Miller| 2003|p=32}}

|

120px

| X-25

| Bensen

| USAF

| 1955

| Commercial light autogyro for downed pilots.{{sfn|Jenkins|Landis|Miller| 2003|p=33}}

|

120px 120px

| X-26 Frigate

| Schweizer

| DARPA, US Army, USN

| 1967

| Training glider for yaw-roll coupling Quiet observation aircraft{{sfn|Jenkins|Landis|Miller| 2003|p=34}}

|

120px

| X-27

| Lockheed

| None

| 1971

| high-performance research aircraft. High-performance fighter{{sfn|Jenkins|Landis|Miller| 2003|p=35}}

| Proposed development of Lockheed CL-1200 Lancer. Canceled and never flew.

120px

| X-28 Sea Skimmer

| Osprey

| USN

| 1970

| Low-cost aerial policing seaplane{{sfn|Jenkins|Landis|Miller| 2003|p=36}}

|

120px

| X-29

| Grumman

| DARPA, USAF, NASA

| 1984

| Forward-swept wing{{sfn|Jenkins|Landis|Miller| 2003|p=37}}

|

120px

| X-30 NASP

| Rockwell

| NASA, DARPA, USAF

| 1993

| Single-stage-to-orbit spaceplane{{sfn|Jenkins|Landis|Miller| 2003|p=38}}

| Canceled and never built.

120px

| X-31

| Rockwell-MBB

| DARPA, USAF, BdV

| 1990

| Thrust vectoring supermaneuverability{{sfn|Jenkins|Landis|Miller| 2003|p=39}}

|

rowspan="2" |120px

| X-32A

| rowspan="2" | Boeing

| rowspan="2" | USAF, USN, USMC, RAF

| 2000

| rowspan="2" | Joint Strike Fighter{{sfn|Jenkins|Landis|Miller| 2003|p=40–41}}

| rowspan="2" |

X-32B

| 2001

120px

| X-33

| Lockheed Martin

| NASA

| 2001

| Half-scale reusable launch vehicle prototype.{{sfn|Jenkins|Landis|Miller| 2003|p=42}}

| Prototype never completed.

120px

| X-34

| Orbital Sciences

| NASA

| 2001

| Reusable pilotless spaceplane.{{sfn|Jenkins|Landis|Miller| 2003|p=43}}

| Never flew.

120px

| X-35A

| rowspan="3" | Lockheed Martin

| rowspan="3" | USAF, USN, USMC, RAF

| 2000

| rowspan="3" | Joint Strike Fighter{{sfn|Jenkins|Landis|Miller| 2003|p=44–45}}

|

120px

| X-35B

| 2001

|First in family to use VTOL. Also used unconventional mode of lift engine (lift fan).

120px

| X-35C

| 2000

120px

| X-36

| McDonnell Douglas

| NASA

| 1997

| 28% scale tailless fighter{{sfn|Jenkins|Landis|Miller| 2003|p=46}}

|

120px

| X-37

| Boeing

| USAF, USSF, NASA

| 2010

| Reusable orbital spaceplane{{sfn|Jenkins|Landis|Miller| 2003|p=47}}

| Drop test performed in 2006. Seven flights to space since 22 April 2010

120px

| X-38

| Scaled Composites

| NASA

| 1998

| Lifting body Crew Return Vehicle{{sfn|Jenkins|Landis|Miller| 2003|p=48}}

|

| X-39

| Unknown

| USAF

|

| Future Aircraft Technology Enhancements (FATE) program.{{sfn|Jenkins|Landis|Miller| 2003|p=49}}

| Designation never officially assigned.

120px

| X-40A

| Boeing

| USAF, NASA

| 1998

| 80% scale Space Maneuver Vehicle X-37 prototype.{{sfn|Jenkins|Landis|Miller| 2003|p=50}}

|

120px

| X-41

| Unknown

| USAF

|

| Maneuvering re-entry vehicle.{{sfn|Jenkins|Landis|Miller| 2003|p=51}}

|

| X-42 {{anchor|X-42 Pop-Up Upper Stage}}

| Unknown

| USAF

|

| Expendable liquid propellant upper-stage rocket.{{sfn|Jenkins|Landis|Miller| 2003|p=52}}

|

120px

| X-43 Hyper-X

| Micro-Craft

| NASA

| 2001

| Hypersonic Scramjet{{sfn|Jenkins|Landis|Miller| 2003|p=53}}

|

120px

| X-44 MANTA

| Lockheed Martin

| USAF, NASA

| 2000

| F-22-based Multi-Axis No-Tail Aircraft thrust vectoring{{sfn|Jenkins|Landis|Miller| 2003|p=54}}

| Canceled, never flew.

120px

| X-45

| Boeing

| DARPA, USAF

| 2002

| Unmanned combat air vehicle (UCAV){{sfn|Jenkins|Landis|Miller| 2003|p=55}}

|

120px

| X-46

| Boeing

| DARPA, USN

| 2003

| Unmanned combat air vehicle (UCAV).{{sfn|Jenkins|Landis|Miller| 2003|p=56}}

| Naval use. Canceled, never flew.

120px

| X-47A Pegasus

| Northrop Grumman

| DARPA, USN

| 2003

| Unmanned combat air vehicle (UCAV){{sfn|Jenkins|Landis|Miller| 2003|p=57}}

| Naval use.

120px

| X-47B

| Northrop Grumman

| DARPA, USN

| 2011

| UCAV

| Naval use.

| X-47C

| Northrop Grumman

| USAF

|

| Manned bomber

| Proposal for a new-generation strategic bomber. Design only.

120px

| X-48

| Boeing

| NASA

| 2007

| Blended Wing Body (BWB){{sfn|Jenkins|Landis|Miller| 2003|p=58}}

|

120px

| X-49 SpeedHawk

| Piasecki

| US Army

| 2007

| Compound helicopter Vectored Thrust Ducted Propeller (VTDP) testbed.Parsch 2024, "DOD 4120.15-L"

|

| X-50 Dragonfly

| Boeing

| DARPA

| 2003

| Canard Rotor/Wing{{sfn|Jenkins|Landis|Miller| 2003|p=60}}

|

120px

| X-51 Waverider

| Boeing

| USAF

| 2010{{Cite web| title = X-51 Waverider makes historic hypersonic flight| publisher = US Air Force Public Affairs| date = 26 May 2010| url = https://www.af.mil/News/story/id/123206525/| access-date = 27 May 2010}}

| Hypersonic scramjet[http://www.globalsecurity.org/military/systems/aircraft/x-51.htm "X-51 Scramjet Engine Demonstrator - WaveRider"] globalsecurity.org. Accessed 2010-05-11.

|

—

| X-52

| —

| —

| —

| —

| Number skipped to avoid confusion with Boeing B-52 Stratofortress.

120px

| X-53

| Boeing

| NASA, USAF

| 2002

| Active Aeroelastic WingJordan 2006

|

| X-54

| Gulfstream

| NASA

|

| Low-noise supersonic transport412015-L in development.

|

120px

| X-55

| Lockheed Martin

| USAF

| 2009

| Advanced Composite Cargo Aircraft (ACCA)Kaufman 2009

|

120px

| X-56

| Lockheed Martin

| USAF/NASA

| 2013

| Active flutter suppression and gust load alleviation

| Part of the high-altitude, long-endurance (HALE) reconnaissance aircraft program.Norris 2012

120px

| X-57 Maxwell

| ESAero/Tecnam

| NASA

| 2023

| Low emission plane powered entirely by electric motors{{cite web|last1=Harrington|first1=J.D.|last2=Kamlet|first2=Matt|last3=Barnstorff|first3=Kathy|title=NASA Hybrid Electric Research Plane Gets X Number, New Name|url=https://www.nasa.gov/press-release/nasa-hybrid-electric-research-plane-gets-x-number-new-name|website=NASA.gov|publisher=NASA|access-date=17 June 2016|date=17 June 2016}}

| Part of NASA's Scalable Convergent Electric Propulsion Technology Operations Research project (SCEPTOR). Cancelled in 2023, never flew.

—

| X-58

| —

| —

| —

| —

| Number skipped; slot apparently assigned to Kratos XQ-58 Valkyrie.[https://www.popularmechanics.com/military/aviation/a22130727/x-58-air-force-valkyrie-drone-loyal-sidekick/ The Air Force Valkyrie Drone, a Sidekick for Human-Piloted Planes, Will Fly This Year]

120px

| X-59 Quesst

| Lockheed Martin

| NASA

| 2024

| Prototype quiet supersonic transport aircraft{{cite web |last1=Jim |first1=Banke |title=NASA's Experimental Supersonic Aircraft Now Known as X-59 QueSST |url=https://www.nasa.gov/aero/nasa-experimental-supersonic-aircraft-x-59-quesst |website=NASA |access-date=28 June 2018 |language=en |date=27 June 2018}}

|

| X-60

| Generation Orbit Launch Services

| USAF

|

| Air-launched rocket for hypersonic flight research{{cite web|url=http://generationorbit.com/u-s-air-force-designates-go1-hypersonic-flight-research-vehicle-as-x-60a/|title=U.S. Air Force Designates GO1 Hypersonic Flight Research Vehicle as X-60A|date=4 October 2018|website=generationorbit.com|access-date=4 October 2018}}

|

120px

| X-61 Gremlins

| Dynetics

| DARPA

| 2020

| Air-launched and air-recoverable reconnaissance unmanned air vehicle (UAV){{cite journal |title=Earthquake damage delays Gremlins trial |journal=Flight International |date=24 September 2019 |url=https://finreader.flightglobal.com/publications-dist/1263/7943/2720/31606/article.html |access-date=28 October 2019}}{{cite journal |title=Dynetics X-61A Gremlins makes first flight, but destroyed after parachute fails |journal=Flight International |date=17 January 2020 |url=https://www.flightglobal.com/military-uavs/dynetics-x-61a-gremlins-makes-first-flight-but-destroyed-after-parachute-fails/136220.article |access-date=13 February 2020}}

|

120px

| X-62 VISTA

| Lockheed Martin/Calspan

| USAF

| 2021

| Variable In-flight Simulator Test Aircraft.

| First flew in 1993 as the NF-16D (for the MATV program). Designated the X-62A during a major research system upgrade in 2021. Assigned to the USAF Test Pilot School.[https://www.dvidshub.net/news/402134/nf-16d-vista-becomes-x-62a-paves-way-skyborg-autonomous-flight-tests Giancarlo Casem (30 Jul 2021) NF-16D VISTA becomes X-62A, paves way for Skyborg autonomous flight tests]

—

|X-63

|ABL Space Systems

|AFRL

|2023

|Modular aerospike engine launch vehicle testbed based on RS1. {{cite web |title=AFRL’s Rocket Lab Past, Present and Future |url=https://afresearchlab.com/technology/afrls-rocket-lab-past-present-and-future/ |website=AFRL |access-date=25 August 2024}}

|The RS1 launch vehicle first flew on Jan 10, 2023. The launch ended in failure. {{Cite news |date=2023-01-11 |title=ABL Space Systems' rocket fails on maiden launch |language=en |work=Reuters |url=https://www.reuters.com/business/aerospace-defense/abl-space-systems-rocket-fails-maiden-launch-2023-01-11/ |access-date=2023-01-11 |archive-date=11 January 2023 |archive-url=https://web.archive.org/web/20230111003416/https://www.reuters.com/business/aerospace-defense/abl-space-systems-rocket-fails-maiden-launch-2023-01-11/ |url-status=live }}

—

|X-64

|Invocon Inc.

|AFRL

|—

|Modular aerospike engine launch vehicle testbed

|

120x120px

|X-65 CRANE

|Aurora Flight Sciences

|DARPA

|2025

|Control of Revolutionary Aircraft with Novel Effectors{{Cite web |last=Hadley |first=Greg |date=2023-05-16 |title=Meet the X-65: DARPA's New Plane Has No External Control Surfaces |url=https://www.airandspaceforces.com/x-65-darpa-new-plane/ |access-date=2023-05-29 |website=Air & Space Forces Magazine |language=en-US}}

|

120x120px

|X-66

|Boeing

|NASA

|2028

|Transonic Truss-Braced Wing{{cite web |last1=O’Shea |first1=Claire |title=Next Generation Experimental Aircraft Becomes NASA's Newest X-Plane |url=https://www.nasa.gov/press-release/next-generation-experimental-aircraft-becomes-nasa-s-newest-x-plane |website=NASA |access-date=13 June 2023 |date=12 June 2023}}

|

See also

Notes

{{reflist|group=N}}

References

{{Reflist}}

Bibliography

{{refbegin}}

  • {{cite book |last1=Jenkins |first1=Dennis R. |first2=Tony |last2=Landis |first3=Jay |last3=Miller |title=American X-Vehicles: An Inventory—X-1 to X-50 |url=https://archive.org/download/NASA_NTRS_Archive_20030067480/NASA_NTRS_Archive_20030067480.pdf |access-date=22 January 2024 |edition=Centennial of Flight |series=Monographs in Aerospace History |volume=31 |date=June 2003 |publisher=NASA History Office |location=Washington, DC |id=SP-2003-4531}}
  • {{cite web | url=https://www.wpafb.af.mil/News/story/id/123035661/ | title=Active Aeroelastic Wing flight research vehicle receives X-53 designation | first=Holly | last=Jordan | year=2006 | publisher=Wright-Patterson Air Force Base | access-date=2010-05-11 | url-status=live | archive-url=https://web.archive.org/web/20110605105552/http://www.wpafb.af.mil/news/story.asp?id=123035661 | archive-date=2011-06-05 }}
  • {{cite web | url=https://www.af.mil/News/story/id/123173711/ | title=Advanced Composite Cargo Aircraft gets X-plane designation |first=Derek | last=Kaufman |year=2009 | publisher=United States Air Force | access-date=2010-05-11}}
  • {{cite book |last=Miller |first=Jay |title=The X-Planes: X-1 to X-45 |edition=first UK|year=1985 |publisher=Midland Counties|isbn=0-904597-46-6}}
  • {{cite book |last=Miller |first=Jay |title=The X-Planes: X-1 to X-45 |edition=third |year=2001 |publisher=Motorbooks International |isbn=1-85780-109-1}}
  • {{cite web | url=http://www.designation-systems.net/usmilav/missing-mds.html | title="Missing" USAF/DOD Aircraft Designations | first=Andreas | last=Parsch |year=2024 | publisher=designation-systems.net | access-date=2010-05-11}}
  • {{cite web |url=http://www.designation-systems.net/usmilav/412015-L(addendum).html |title=DOD 4120.15-L - Addendum |last=Parsch |first=Andreas |year=2024 |publisher=designation-Systems.Net | access-date=2010-05-11}}
  • {{cite web | url=http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=aerospacedaily&id=news/asd/2012/02/01/02.xml | title=USAF Reveals Latest X-Plane: X-56A| first=Guy| last=Norris|date=February 2012 |publisher=Aviation Week and Space Technology| access-date=2012-02-11}}

{{refend}}

External links

  • {{Commons category-inline}}
  • [https://web.archive.org/web/20031220121649/http://www.centennialofflight.gov/essay/Evolution_of_Technology/early_X_planes/Tech27.htm Early X-planes]
  • [https://web.archive.org/web/20060928220628/http://lisar.larc.nasa.gov/BROWSE/xplane.html X-15 Videos by NASA]

{{X-planes}}

{{Lists of aircraft}}

{{DEFAULTSORT:X-Planes, List Of}}

Category:Lists of aircraft by role

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Category:United States experimental aircraft

nl:Lijst van Amerikaanse X-vliegtuigen