The Grumman X-29 explored a number of new technologies, the most immediately obvious being the forward swept wings (FSW) and canard control surface. The inherent aerodynamic instability of this arrangement required the use of computerised fly-by-wire control, and advanced composite materials were needed to make the wing sufficiently rigid without being unacceptably heavy.

Development

Two X-29As were built by Grumman Aerospace Corporation, and first flown in 1984. The two aircraft were made from existing Northrop F-5A Freedom Fighter airframes. The test program of the two planes continued for over a decade, and on December 13, 1985 one of them became the first FSW aircraft to fly supersonically in level flight.

The X-29A demonstrated excellent control and maneuvering qualities at an angle of attack up to 45 degrees.

The wing configuration made the craft inherently unstable. It could fly only with the constant corrections (up to 40 per second) provided by the computerised flight control system. The system was made up of three redundant digital computers backed up by three redundant analog computers. It was estimated that a total failure of the system was as unlikely as a mechanical failure in a normal airplane.

The first craft built is now on display in the USAF Museum.

Specifications

General characteristics

• Crew: 1
• Length: 48 ft 1 in (14.7 m)
• Wingspan: 27 ft 2 in (8.8 m)
• Height: 14 ft 3 in (4.3 m)
• Maximum takeoff: 17,300 lb (7,700 Kg)

Performance

• Maximum speed: 1,200 mph (1,930 km/h)
• Range: miles ( km)
• Service ceiling: 55,000 ft (16.8 Km)
• Rate of climb: ft/min ( m/min)
• Wing loading: lb/ft² ( kg/m²)
• Thrust/weight:

References

American X-Vehicles (.pdf)

Related content

Related development: T-38 - F-5 - F-20

Comparable aircraft:

Designation sequence: X-26 - X-27 - X-28 - X-29 - X-30 - X-31 - X-32

See also: List of experimental aircraft