X-29

X-29
A Grumman X-29 in flight
Role	Experimental aircraft
National origin	United States
Manufacturer	Grumman
First flight	14 December 1984
Status	Retired
Primary user	DARPA
Number built	2

The Grumman X-29 was an American experimental aircraft that tested a forward-swept wing, canard control surfaces, and other novel aircraft technologies. The X-29 was developed by Grumman, and the two built were flown by NASA and the United States Air Force. The aerodynamic instability of the X-29's airframe required the use of computerized fly-by-wire control. Composite materials were used to control the aeroelastic divergent twisting experienced by forward-swept wings, and to reduce weight. The X-29 first flew in 1984; two X-29s were flight tested over the next decade.

Two X-29As were built by Grumman from two existing Northrop F-5A Freedom Fighter airframes (63-8372 became 82-0003 and 65-10573 became 82-0049) after the proposal had been chosen over a competing one involving a General Dynamics F-16 Fighting Falcon. The X-29 design made use of the forward fuselage and nose landing gear from the F-5As with the control surface actuators and main landing gear from the F-16. The technological advancement that made the X-29 a plausible design was the use of carbon-fiber composites. The wings of the X-29, made partially of graphite epoxy, were swept forward at more than 33 degrees; forward-swept wings were first trialed 40 years earlier on the experimental Junkers Ju 287 and OKB-1 EF 131. The Grumman internal designation for the X-29 was "Grumman Model 712" or "G-712".

The X-29 is described as a three surface aircraft, with canards, forward-swept wings, and aft strake control surfaces, using three-surface longitudinal control. The canards and wings result in reduced trim drag and reduced wave drag, while using the strakes for trim in situations where the center of gravity is off provides less trim drag than relying on the canard to compensate.

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