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The Bell X-22 is an American V/STOL X-plane with four tilting ducted fans. Takeoff was to selectively occur either with the propellers tilted vertically upwards, or on a short runway with the nacelles tilted forward at approximately 45°. Additionally, the X-22 was to provide more insight into the tactical application of vertical takeoff troop transporters such as the preceding Hiller X-18 and the X-22's successor, the Bell XV-15. Another program requirement was a true airspeed in level flight of at least 525 km/h (326 mph; 283 knots).

X-22
Bell X-22 on the tarmac
Role	V/STOL prototype Type of aircraft
Manufacturer	Bell Helicopters
First flight	17 March 1966
Status	1 Stored, other destroyed
Number built	2

Design and development

In 1962, the United States Navy announced their request for two prototype aircraft with V/STOL capability, powered by four ducted fan nacelles. Bell Helicopters already had extensive experience with VTOL aircraft and was able to utilize an already developed test mockup. In 1964 the prototype, internally referred to by Bell as Model D2127, was ordered by the Navy and received the X-22 designation. It was unveiled at an event in Niagara Falls in May 1965.[1][2]

Three-bladed propellers were mounted on four wings and, synchronized through a wave-interconnection system, were connected to four gas turbines which, in turn, were mounted in pairs on the rear wings. Maneuvering was achieved by tilting the propeller blades in combination with control surfaces (elevators and ailerons), which were located in the thrust stream of the propellers.

Operational history

The maiden flight of the prototype occurred on 17 March 1966. In contrast to other tilt-rotor craft (such as the Bell XV-3), transitions between hovering and horizontal flight succeeded nearly immediately. However, interest increased more towards VTOL and V/STOL properties, not the specific design of the prototype.

Due to failure of a propeller control, described by test pilot Stanley Kakol as the only non-redundant component in the power chain, the prototype crashed on 8 August 1966 and technicians stripped it for components in order to make the second prototype flight capable. The fuselage was still used as a simulator for some time afterwards.

The second X-22 first flew on 26 August 1967. Early that year, it was equipped with a variable flight control and stabilizer system from Cornell Aeronautical Laboratory, which improved flight performance. Although the X-22 was considered to be the best aircraft of its type at the time, the program was canceled. The required maximum speed of 525 km/h was never reached. The second prototype was moved to Cornell Aeronautical Laboratory for further testing; the last flight occurred in 1988. Although the ducted fan propellers were considered usable, they were not used again on a US military aircraft until the F-35B.

Surviving aircraft

Although not on display, the only currently remaining craft, 151521, is currently stored by the Niagara Aerospace Museum, New York.[3]

According to the employees at the Museum, the craft was held onto after being debated for scrapping by the Navy.

Specifications (X-22A)

General characteristics

• Crew: two + six passengers
• Length: 39 ft 7 in (12.07 m)
• Wingspan: 39 ft 3 in (11.96 m)
  
• Wingspan (front wing): 22.916 ft (6.98 m)
• Height: 20 ft 8 in (6.31 m)
• Empty weight: 10,478 lb (4,753 kg)
• Max takeoff weight: 17,644 lb (8,003 kg)
• Powerplant: 4 × General Electric-YT58-GE-8D turboshaft engines, 1,267 hp (945 kW) each
• Propellers: three-bladed propellers mounted in wingtip swivelling ducts, 7 ft 0 in (2.13 m) diameter

Performance

• Maximum speed: 221 kn (254 mph, 409 km/h)
• Range: 387 nmi (445 mi, 716 km)
• Service ceiling: 27,800 ft (8,500 m)
  
• Hover ceiling in ground effect : 12,000 ft (3,658 m)
• Hover ceiling out of ground effect : 6,000 ft (1,829 m)

See also

Aircraft of comparable role, configuration, and era

• Bell Boeing V-22 Osprey

Related lists

• List of VTOL aircraft

References

Citations

Bibliography

External links

• aerospaceweb.org

На других языках

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[de] Bell X-22

Die Bell X-22 war ein V/STOL-Experimentalflugzeug mit vier kippbaren Mantelpropellern. Der Start sollte wahlweise senkrecht, mit um 90° nach oben geschwenkten Propellern, oder auf einer kurzen Startbahn mit etwa 45° nach vorn geschwenkten Propellern erfolgen können (V/STOL = Vertical/Short Take-Off and Landing, senkrecht/kurz starten und landen). Gleichzeitig sollte die X-22 mehr Aufschluss über die taktische Verwendbarkeit eines Senkrechtstarters als Truppentransporter bringen, so wie vor ihr die Hiller X-18 und nach ihr die Bell XV-15. Eine weitere Vorgabe bestand darin, im Horizontalflug eine Geschwindigkeit von mindestens 525 km/h zu erreichen.

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- [en] Bell X-22

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[fr] Bell X-22

Le X-22 est un avion à décollage et atterrissage verticaux expérimental américain, doté de 4 rotors basculants carénés développé par la firme Bell Aircraft Corporation dans les années 1960. L'appareil peut décoller à la verticale lorsque ses rotors sont placés à 90° ou après une courte phase de roulage les rotors étant dans ce cas placés à un angle de 45°. Un des buts du programme est de définir les capacités tactiques d'un avion de transport à rotors basculants. Une exigence du programme est que l'appareil puisse atteindre une vitesse de 525 km/h. Lors du développement les ingénieurs utilisent les données recueillies dans le cadre du programme X-18 qui a déjà défriché les problèmes techniques inhérents à cette formule.

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[it] Bell X-22

Il Bell X-22 era un convertiplano sperimentale di tipo V/STOL con quattro turboventole intubate basculanti. Il decollo poteva essere effettuato sia verticalmente con i rotori diretti verso l'alto che su una pista corta con le gondole dei motori inclinate di circa 45°. Inoltre, l'X-22 doveva fornire un approccio più esteso al problema della creazione di un mezzo da trasporto tattico di truppe a decollo verticale, come il predecessore Hiller X-18 così come del suo successore Bell XV-15.

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[ru] Bell X-22

Белл X-22 (англ. Bell X-22) — американский экспериментальный самолёт вертикального взлёта и посадки. Разработан компанией «Белл аэросистемз». Построен для проведения исследований в полёте с использованием поворотных канальных движителей. Самолёт X-22A первый раз поднялся в воздух 17 марта 1966 года. Всего было построено два самолёта, один из них потерян в ходе испытаний. Испытания второго прототипа продолжались до закрытия программы в 1988 году.

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