Grumman X-29

infobox Aircraft
name = Grumman X-29
type = Experimental Fighter
manufacturer = Grumman

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caption = A Grumman X-29 in flight
designer =
first flight = 1984
introduction =
number built = 2
status =
unit cost =
primary user = DARPA
more users =
developed from =
variants with their own articles =

The Grumman X-29 was an experimental aircraft that explored a number of new technologies; the most immediately obvious being the forward-swept wings and canard control surface. The inherent aerodynamic instability of this arrangement required the use of computerized fly-by-wire control, and advanced composite materials were needed to make the wing sufficiently rigid without being unacceptably heavy. The X-29 first flew in 1984 and two X-29s were flight tested over the next decade.

Design and development

Two X-29As were built by Grumman Aerospace Corporation, the first flight taking place in 1984. The aircraft were adapted from two existing Northrop F-5A Freedom Fighter airframes (63-8372 became 82-0003 and 65-10573 became 82-0049) [cite web | url=http://www.ais.org/~schnars/aero/x-planes.htm | title = The X-Planes: From X-1 to X-34 | accessdate=2008-02-11 | date = 1995 | editor = Andreas Gehrs-Pahl] (after the proposal had been chosen over a competing one involving a General Dynamics F-16 Fighting Falcon). The X-29 design made use 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 Grumman internal designation for the X-29 was "Grumman Model 712" or "G-712".Donald, David ed. "Grumman X-29A", "The Complete Encyclopedia of World Aircraft". Barnes & Nobel Books, 1997. ISBN 0-7607-0592-5.]

On December 13, 1985 one of the X-29s became the first forward swept wing aircraft to fly in supersonic, level flight. The earlier Junkers Ju 287 had been the first jet aircraft with forward-swept wings. The test program of the two X-29s continued from 1984 to 1991.

The X-29A demonstrated excellent control and maneuvering qualities at an angle of attack up to 45 degrees. There was also a decrease in turbulence. However, the wing configuration made the craft inherently unstable and it could fly only with the constant corrections (up to 40 per second) provided by the computerized flight control system. The 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. It was estimated that a total failure of the system was as unlikely as a mechanical failure in an airplane with a conventional arrangement.

The first craft built is now on display in the National Museum of the United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio. The other craft is on display at the Dryden Flight Research Center on Edwards Air Force Base. A full scale model is on display at the National Air and Space Museum's National Mall building in Washington, DC. [ [http://www.nasm.si.edu/exhibitions/gal213/index.cfm Exhibits on view] , National Air and Space Museum, accessed 6 May 2007]

pecifications (X-29)

aircraft specifications
plane or copter?=plane
jet or prop?=jet
ref=
crew=one pilot
capacity=
payload main=4,000 lb
payload alt=1,810 kg
length main=48 ft 1 in
length alt=14.7 m
span main=27 ft 2 in
span alt=8.8 m
height main=14 ft 3 in
height alt=4.3 m
area main= 188 ft²
area alt= 57 m²
airfoil=
empty weight main= 13,800 lb
empty weight alt= 6,260 kg
loaded weight main= 17,800 lb
loaded weight alt= 8,070 kg
useful load main=
useful load alt=
max takeoff weight main=17,800 lb
max takeoff weight alt= 8,070 kg
more general=

engine (jet)=General Electric F404
type of jet=turbofan
number of jets=1
thrust main=16,000 lbf
thrust alt=71.2 kN
thrust original=
afterburning thrust main=
afterburning thrust alt=
max speed main=Mach 1.6
max speed alt=1,200 mph, 1,820 km/h
cruise speed main=
cruise speed alt=
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main=
range alt=
ceiling main=55,000 ft
ceiling alt=16,800 m
climb rate main=
climb rate alt=
loading main=
loading alt=
thrust/weight=
power/mass main=
power/mass alt=
more performance=

armament=
avionics=

ee also

aircontent
related=
* Northrop F-5
similar aircraft=
* Su-47
lists=
* List of experimental aircraft
see also=
* Forward-swept wing
* Junkers Ju 287

References

* [http://history.nasa.gov/monograph31.pdf American X-Vehicles, NASA]

External links

* [http://www.nasa.gov/centers/dryden/history/pastprojects/X29/ NASA's X-29 website]
* [http://www.nasa.gov/centers/dryden/news/FactSheets/FS-008-DFRC.html NASA's X-29 factsheet]
* [http://www.fighter-planes.com/info/x29.htm Grumman X-29 at fighter-planes.com]