Bell X-5

The Messerschmitt P.1101 V1 prototype was captured by United States troops in April 1945 from an experimental facility at Oberammergau, Germany. It was brought back to the United States, eventually being delivered to the Bell Aircraft factory at Buffalo, New York. Although incomplete and damaged in transit, company engineering staff studied the design closely.Winchester 2005, p. 37. The P.1101 had a wing sweep that could be adjusted on the ground from 30, 40, to 45 degrees. However, this was for testing only and never intended as an operational feature.{{cite book |last1=Christopher |first1=John |title=The Race for Hitler's X-Planes : Britain's 1945 Mission to Capture Secret Luftwaffe Technology. |date=1 June 2013 |publisher=History Press |isbn=978-0752464572 |pages=157–160}} The Bell team, led by Chief Designer Robert J. Woods, submitted a proposal for a similar design, but with in-flight wing adjustment capability.

Although superficially similar, the X-5 was much more complex than the P.1101, with three sweep positions: 20°, 40° and 60°, creating an inflight "variable-geometry" platform. A jackscrew assembly moved the wing's hinge along a set of short horizontal rails, using disc brakes to lock the wing into its inflight positions. Moving from full extension to full sweep took less than 30 seconds. The articulation of the hinge and pivots partly compensated for the shifts in center of gravity and center of pressure as the wings moved.{{Citation needed|date=February 2025}}

Even so, the X-5 had vicious spin characteristics arising from the aircraft's flawed aerodynamic layout, particularly a poorly positioned tail and vertical stabilizer which, in some wing positions, could lead to an irrecoverable spin. This violent stall / spin instability would eventually cause the destruction of the second aircraft and the death of its Air Force test pilot in 1953.Hallion 1984, p. 52.

The unfavorable spin characteristics also led to the cancellation of tentative plans by the United States Air Force to modify the X-5's design into a low-cost tactical fighter for NATO and other foreign countries.Hallion 1984, p. 47.

Two X-5s were built (serial numbers 50-1838 and 50-1839). The first was completed 15 February 1951, and the two aircraft made their first flights on 20 June and 10 December 1951. Almost 200 flights were made at speeds up to Mach 0.9 and altitudes of {{convert|40,000|ft|m|abbr=on}}. One aircraft was lost on 14 October 1953, when it failed to recover from a spin at 60° sweepback. Air Force Captain Ray Popson died in the crash at Edwards Air Force Base. The other X-5 remained at Edwards and continued active testing until 1955, and remained in service as a chase plane until 1958.

The X-5 successfully demonstrated the advantage of a swing-wing design for aircraft intended to fly at a wide range of speeds. Despite the X-5's stability problems, the concept was developed to an outboard rather than inboard hinge,{{Cite web|title=Swing Wings|url=https://www.airspacemag.com/flight-today/swing-wings-9189621/|access-date=2021-07-18|website=Air & Space Magazine|language=en}} and was later successfully implemented in such aircraft as the General Dynamics F-111 and Grumman F-14 Tomcat, the Mikoyan Gurevich MiG-23 and MiG-27, the Sukhoi Su-17/20/22 and Su-24, the Tupolev Tu-22M and Tu-160, the Panavia Tornado and the Rockwell B-1 Lancer.

The sole surviving X-5 is now at the National Museum of the United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio. It was delivered to the museum in March 1958. It is displayed in the museum's Research & Development Hangar.[https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195758/bell-x-5/ "Bell X-5".] National Museum of the United States Air Force. Retrieved: 22 October 2016.

File:Bell X-5 afg-041110-046.svg

{{Aircraft specs

|ref=The X-planes : X-1 to X-29{{cite book |last1=Miller |first1=Jay |title=The X-planes : X-1 to X-29 |date=1983 |publisher=Speciality |location=Marine on St. Croix |isbn=0933424353 |pages=56–63}}

|prime units?=imp

|crew=1

|length ft=33

|length in=4

|length note=

|span ft=30

|span in=6

|span note=

|swept ft=20

|swept in=9

|swept note=at 60° sweep{{citation needed|date=April 2020}}

|height ft=12

|height in=0

|height note=

|wing area sqft=175

|wing area note=

|aspect ratio=

|airfoil=root: NACA 64A011; tip: NACA 64A08.28{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |access-date=16 April 2019}}

|empty weight lb=6350

|empty weight note=

|gross weight lb=9875

|gross weight note=

|max takeoff weight lb=

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|more general=

|eng1 number=1

|eng1 name=Allison J35-A-17A

|eng1 type=turbojet engine

|eng1 lbf=4900

|eng1 note=at sea level

|max speed mph=705

|max speed note=

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|never exceed speed mph=

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|range miles=750

|range note=

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|ceiling ft=42000

|ceiling note=

|g limits=

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|thrust/weight=0.5{{citation needed|date=April 2020}}

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}}

{{aircontent

|related=

|similar aircraft=

• Grumman XF10F Jaguar
• Messerschmitt P.1101
• North American F-86 Sabre
• Saab 29 Tunnan
• Škoda-Kauba P14

|lists=

• List of experimental aircraft

}}

;Notes

{{Reflist}}

;Bibliography

{{Refbegin}}

• Hallion, Richard P. On The Frontier: Flight Research At Dryden 1946–1981 (NASA SP4303). Washington, DC: National Aeronautics and Space Administration, 1984 (revised 2003 in Smithsonian edition). {{ISBN|1-58834-134-8}}.
• Winchester, Jim. "Bell X-5." Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft. Kent, UK: Grange Books plc., 2005. {{ISBN|1-84013-809-2}}.

{{Refend}}

{{Commons category|Bell X-5}}

• [https://web.archive.org/web/20200425225303/https://history.nasa.gov/monograph31.pdf American X-Vehicles: An Inventory X-1 to X-50, SP-2000-4531 – June 2003; NASA online PDF Monograph]
• {{cite magazine|magazine=Popular Science|author=Bonnier Corporation|title=Dart Shaped Plane Sweeps Wings Back In Flight|url=https://books.google.com/books?id=lyEDAAAAMBAJ&pg=PA84|date=August 1951|publisher=Bonnier Corporation|page=84}}

{{Bell Aircraft}}

{{X-planes}}

{{Authority control}}

Category:Edwards Air Force Base

Category:Variable-sweep-wing aircraft

X-05, Bell

Category:Single-engined jet aircraft

X-5

Category:Mid-wing aircraft

Category:Aircraft first flown in 1951

Category:Aircraft with retractable tricycle landing gear