Grumman X-29 Forward-Swept Wing Technology Demonstrator
The unique Grumman X-29 design - with its forward-swept wings - was born from the existing airframe of the Northrop F-5A Freedom Fighter series.
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The Grumman X-29 aircraft was a technology demonstrator appearing in the latter years of the Cold War (1947-1991). The design was of a most unique shape - made notable by its forward-swept wings - and was the first aircraft with such an arrangement to fly supersonically (the World War 2-era Junkers Ju 287 was the first jet to utilize forward-swept wings but only ever flew subsonically). The X-29 would serve as a flying testbed for seven years with a tenure beginning in 1984, providing much research in advanced wing concepts and moving canards.
Externally, the X-29 was a modified airframe belonging to the Northrop F-5 Freedom Fighter lightweight aircraft. The X-29 featured light-yet-rigid, composite-based, forward-swept monoplane wings emerging from the rear fuselage sides. The cockpit was situated well-forward in the fuselage with a largely unobstructed view out of the glass canopy for the sole pilot. The aircraft featured its canards at midships aft of the cockpit and ahead of the mainplanes. The empennage included a single vertical tailfin. No horizontal tailplanes were used as the mainplanes were seated far enough back to take their place. A single General Electric F404-GE-400 turbofan was used for propulsion and this outputting at 16,000lbs. All told, the aircraft could reach speeds of Mach 1.5+ and a ceiling of 55,000 feet. Its undercarriage supported components retained by the Northrop F-5 and also taken from a General Dynamics F-16 "Falcon".
The Grumman X-29 was an internally complex design centered around three redundant Fly-By-Wire (FBW) computers backed by three redundant analog computers. Fly-by-wire technology was necessary as the unconventional layout of the airframe proved to be highly unstable inflight without assistance. The redundancy of the systems assured that there would be no catastrophic failure of the subsystems while inflight and the analog arrangement directly backed up the digital suite to provide a further fail safe. The X-29 was a true testbed in every sense of the word, its fly-by-wire technology now commonplace to both military- and civilian-minded aircraft alike.
The Defense Advanced Research Projects Agency (DARPA) was the primary operator of the two X-29A demonstrators completed. These carried serial numbers 82-0003 and 82-0049. Their test regime spanned from 1984 through to 1991 before the project was officially ended. The aircraft pairing then went on to prove many aeronautic concepts viable and served to forward American military aviation into the following decade.
The two working examples themselves manage to survive their years of testing with one of the demonstrators ending its career as a showpiece at the National Museum of the United States Air Force in Dayton, Ohio. The other resided at Dryden Flight Research Center at Edwards AFB.
The National Air and Space Museum of Washington, D.C. displays a fiberglass scale model of the X-29 in its facility rafters.