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The Bell X-14 (Bell Type 68) is an experimental VTOL aircraft flown in the United States in the 1950s. The main objective of the project was to demonstrate vectored thrust horizontal and vertical takeoff, hover, transition to forward flight, and vertical landing.

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X-14
Bell Type 68 VTOL
Role	Experimental VTOL Type of aircraft
Manufacturer	Bell Aircraft
First flight	19 February 1957; 65 years ago (1957-02-19)
Retired	29 May 1981; 41 years ago (1981-05-29)
Status	Museum Display
Primary users	NASA United States Air Force
Produced	1
Number built	1

Design and development

External image
Bell X-14 thrust vectoring vanes
View of the X-14's thrust vectoring vanes used to transition from vertical to horizontal flight from the Ropkey Armor and Aviation Museum.

Bell constructed the X-14 as an open-cockpit, all-metal (duralumin) monoplane for the USAF. It was powered by two Armstrong Siddeley Viper turbojet engines equipped with thrust deflectors sited at the aircraft's centre of gravity. The engines are fixed in position; transition from vertical to horizontal flight is achieved with a system of movable vanes that control the direction of engine thrust.[1][2] Top speed was 180 miles per hour (290 km/h) with a service ceiling of 20,000 feet (6,100 m). The X-14 was designed using existing parts from two Beechcraft aircraft: wings, ailerons, and landing gear of a Beech Bonanza and the tailcone and empennage of a Beech T-34 Mentor.[3]

Operational history

The X-14 first flew on 19 February 1957 as a vertical takeoff, hover, then vertical landing. The first transition from hover to horizontal flight occurred on 24 May 1958. In 1959, its Viper engines were replaced with General Electric J85 engines. That year the aircraft was delivered to the NASA Ames Research Center as the X-14A. During the development of the P.1127, Hawker test pilots Bill Bedford and Hugh Merewether visited NASA Ames to fly the X-14 and acquaint themselves with jet V/STOL aircraft handling prior to the first flights of the prototype P.1127.[3] It served as a test aircraft with NASA until 1981.

The X-14 project provided a great deal of data on VTOL (Vertical TakeOff and Landing) type aircraft and flight control systems.

In 1971, the X-14A was fitted with new engines (General Electric J85-GE-19) and redesignated the X-14B. An onboard computer and digital fly-by-wire control system were also installed to enable emulation of landing characteristics of other VTOL aircraft.

The X-14B was used in this test role until it was damaged beyond repair in a landing accident on 29 May 1981. At the time, there were plans to develop an X-14C with an enclosed cockpit. There were also plans for an X-14T trainer. None of these further versions got beyond the planning stage.

During all of its years of service, the X-14 was flown by over 25 pilots with no serious incidents or injuries.

Aircraft serial numbers

Although there was only one airframe, it changed serial numbers with every major upgrade.

• X-14 - USAF 56-4022
• X-14A - NASA 234 (N234NA).
• X-14B - NASA 704 (N704NA).

Surviving aircraft

The X-14B was rescued from the scrap yard in 1991 and is undergoing renovation as part of the Ropkey Armor and Aviation Museum.[4][5]

Specifications (X-14B)

Data from Bell aircraft since 1935[6]

General characteristics

• Crew: 1
• Length: 26 ft 0 in (7.92 m)
• Wingspan: 33 ft 9.5 in (10.300 m)
• Wing area: 179.52 sq ft (16.678 m²)
• Airfoil: root: NACA 23016.5; tip: NACA 23012[7]
• Empty weight: 3,173 lb (1,439 kg)
• Gross weight: 4,269 lb (1,936 kg)
• Powerplant: 2 × General Electric J85-GE-19 turbojet engines, 3,015 lbf (13.41 kN) thrust each

Performance

• Maximum speed: 172 mph (277 km/h, 149 kn)
• Range: 300 mi (480 km, 260 nmi)
• Service ceiling: 18,000 ft (5,500 m)
• Thrust/weight: 1.4

Avionics
Auto-stabilisation and computer-controlled engine controls.

See also

Aircraft of comparable role, configuration, and era

• Hawker Siddeley P.1127

Related lists

• List of experimental aircraft
• List of VTOL aircraft
• List of X-planes

References

Further reading

• Bridgman, Leonard, ed. (1958). Jane's All the World's Aircraft 1958-59. London: Jane's All the World's Aircraft Publishing Co. Ltd. pp. 258–259.
• Markman, Steve; Holder, William G. (2000). Straight up : a history of vertical flight. Atglen: Schiffer Pub. ISBN 0-7643-1204-9.

На других языках

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- [en] Bell X-14

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[fr] Bell X-14

Le Bell X-14 (ou Bell Type 68) est un avion à décollage et atterrissage verticaux (ADAV) expérimental développé aux États-Unis dans les années 1950.

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[it] Bell X-14

Il Bell X-14, designazione aziendale Bell Type 68, fu un aereo VTOL sperimentale realizzato dall'azienda statunitense Bell Aircraft Corporation negli anni cinquanta.

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