Bell X-14

From Wikipedia, the free encyclopedia

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

[edit] Development

The Bell Aircraft Company constructed the X-14 as an open-cockpit, all-metal monoplane. 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 stationary during all stages of flight. The transition from vertical to horizontal flight is achieved with a system of movable vanes that control the direction of engine thrust. Top speed is 180 miles per hour and a maximum ceiling of 20,000 feet. The X-14 was designed using existing parts from two Beech aircraft. The wings, ailerons, and landing gear of a Beech Bonanza and the tail sections of a Beech T-34 Mentor airplane.

[edit] Operational history

The X-14 took its first flight on February 19, 1957 as a vertical takeoff, hover, then vertical landing. The first transition from hover to horizontal flight occurred on May 24, 1958. In 1959, its Viper engines were replaced with General Electric J85 engines. That year the aircraft was also delivered to the NASA Ames Research Center as the X-14A. 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. The X-14A also was used by NASA for research on lunar landing maneuvers. The X-14A aircraft flight control system was similar to the one proposed for the Lunar Module. Neil Armstrong once flew it as a Lunar-landing trainer.

In 1971, the X-14A was fitted with new engines and redesignated the X-14B. The two new powerplants were GE J85-GE-19s. An onboard computer and digital fly-by-wire control system was 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 May 29, 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. It was the only open cockpit X-plane.

[edit] Aircraft serial number

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

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

[edit] Specifications (X-14A)

[edit] General characteristics

• Crew: one pilot
• Length: 25 ft 0 in (7.62 m)
• Wingspan: 34 ft 10 in (10.36 m)
• Height: 8 ft 0 in (2.40 m)
• Wing area: ft² ( m²)
• Empty: lb ( kg)
• Loaded: 3,100 lb (1,406 kg)
• Maximum takeoff: 4,269 lb (1,936 kg)
• Powerplant: 2x Armstrong Siddeley Viper 8, 1,750 lbf (7.8 kN) thrust each

[edit] Performance

• Maximum speed: 172 mph (277 km/h)
• Range: 300 miles (482 km)
• Service ceiling: 20,000 ft (6,096 m)
• Rate of climb: ft/min ( m/min)
• Wing loading: lb/ft² ( kg/m²)
• Thrust-to-Weight: 1:0.9

[edit] Related content

Related development:

Comparable aircraft:

Designation sequence: X-11 - X-12 - X-13 - X-14 - X-15 - X-16 - X-17

See also:

• List of experimental aircraft
• X-plane