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X-22
Bell X-22 on the tarmac
Role	V/STOL prototype
Manufacturer	Bell Aircraft Corporation
First flight	17 March 1966
Status	1 preserved in museum
Primary user	Bell
Number built	2

The Bell X-22 was a United States V/STOL X-plane with four tilting ducted fans. Take-off 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 take-off troop transporters such as the preceding Hiller X-18 and the X-22 successor, the Bell XV-15. Another program requirement was a true airspeed in level flight of at least 525 km/h (283 mph; 326 knots).

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

History

In 1962, the US Navy announced their request for two prototype aircraft with V/STOL capability, powered by four ducted fan nacelles. Bell Helicopter already had intensive 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.

Maiden flight of the prototype occurred on March 17, 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 prop control, described by the test pilot, Stanley Kakol, as the only non redundant component in the power chain, the prototype crashed on August 8, 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 August 26 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. The craft is currently on display in the Niagara Aerospace Museum, New York.

Although the ducted fan propellers were considered usable, they were never since utilized again on a US military aircraft.

Specifications (X-22A)

Bell X-22 Partial Cockpit View

General characteristics

• Crew: Two
• Length: 39 ft 7 in (12.07 m)
• Wingspan: 39 ft 3 in (rear wings) / 22 ft 11 in (front wings) (11.96 m / 7.01 m)
• Height: 20 ft 8 in (6.31 m)
• Empty weight: 10,478 lb (4,763 kg)
• Max takeoff weight: 17,644 lb (8,020 kg)
• Powerplant: 4× General Electric-YT58-GE-8D turboshafts, 1,267 hp (932 kW) each
• * Propeller Diameter: 2.13 m (7 ft)

Performance

• Maximum speed: 221 knots (410 km/h / 255 mph)
• Range: 445 mi (712 km)
• Service ceiling: 27,800 ft (8,475 m)
• Hovering Altitude with Wing In Ground: 12,000 ft (3,658 m)
• Hovering Altitude without Wing In Ground: 6,000 ft (1,829 m)

See also

United States Air Force portal

Comparable aircraft

• V-22
  

Related lists

• List of VTOL aircraft
  

External links

• avia.russian.ee
• aerospaceweb.org