Grumman X-29: Expanding Aerodynamic Stability (The X-Plane Series Book 3)

The Grumman X-29 was an experimental aircraft that tested a forward-swept wing, canard control surfaces, and other novel aircraft technologies. The aerodynamic instability of this arrangement increased agility but required the use of computerized fly-by-wire control. Composite materials were used to control the aeroelastic divergent twisting experienced by forward-swept wings, also reducing the weight. Developed by Grumman, 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. 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 partly of graphite epoxy, were swept at more than 33 degree forward.
The X-29 is described as a three surface aircraft, with canards, forward-swept wings, and aft strake control surfaces. NASA Dryden FRC cites "use of 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.
The X-29A demonstrated high maneuvering and control in flight testing. A maximum angle of attack of 67° was reached. The configuration, combined with a center of gravity well aft of the aerodynamic center, made the craft inherently unstable. Stability was provided by the computerized flight control system making 40 corrections per second. The flight control system was made up of three redundant digital computers backed up by three redundant analog computers; any of the three could fly it on its own, but the redundancy allowed them to check for errors. Each of the three would "vote" on their measurements, so that if any one was malfunctioning it could be detected.
This book describes the aircraft, it’s design and construction and testing. Also included are detailed test results on both low and high angles of attack.
69 pages, over 50 photos and illustrations most in full color. Contents hyperlinked for easy navigation.