The X-29 was a fantastic looking research aircraft built by Grumman in the 1980s. As something that looks straight out of an episode of Thunderbirds, it's worth peering a little closer at what made this aircraft special.
With it's forward swept wings and sleek, long fuselage, the X-29 was certainly a looker. Like it's bigger brother, our Flite Test DIY versioncan also turn some heads - even if it is only foam board and not an array of high-tech composite alloys. As an experimental aircraft, this plane was extremely successful. Let's look at why this was.
Radically Different
The whole point of the X-29 was to investigate exactly what the limits of aircraft design were by testing new concepts. These included forward-swept wings. During World War Two, both Germany and the United States had experimented with this but had found that their aluminum airframes limited how far they could advance. At higher speeds, the forward swept wings were bending under the stress of twisting forces. The Junkers Ju 287, for instance, was unsuccessful largely because of this.
Many previous experiments had been unsuccessful due to torsional forces bending forward-swept wings.
Over time, however, better composite materials allowed stronger, more rigid wings to be built for aircraft. During the 1960s, the Hansa Jet HFB-320 was the first civilian jet to use a wing with a forward sweep. By the time the X-29 came around, its wings were made with aeroelastic tailoring. This means that they allowed some twisting without compromising the structure of the airframe. This state-of-the-art technology was something that the X-29 would go on to prove was viable and could be used by future commercial and military aircraft.
Two X-29 demonstrator aircraft were built for NASA at a cost of $87 million.
Designed for instability
Unlike a normal jet aircraft, the wing configuration of the X-29 was quite different: the main wing was positioned far back. Infront were the forward-mounted canards. These contributed to lifting whilst also acting as the main pitch control instead of a conventional elevator. The wing's ailerons were also flaps (flaperons) and were used to change the camber of the wing. Each one of these control surfaces was controlled electronically by a complex fly-by-wire computer system that provided the artificial stability necessary for straight and level flight. With this in mind, it's even more amazing what a great job Andres did design the very stable Flite Test X-29!
With a long fuselage and short stubby wings, the aircraft was designed to be unstable.
Here's a short 3 minute video that explains more about the inherent instability of the experimental X-29.
Performance Gains
Thanks to its design, the X-29 had some excellent flight characteristics. Firstly, the wingtips could remain unstalled at various angles of attack. This was because the forward-swept shape allowed air to flow inwards rather than outwards. Also, at rather aggressive attitudes, the aircraft could high alpha and remain controllable again due to the airflow direction which left the flaperons and canards in clean air.
Airflow of a forwardly swept wing naturally directs air inwards.
The X-29 was the first forward-swept wing design to travel through the sound barrier. It could fly at a maximum speed of Mach 1.6. Although it didn't prove that there was a reduction in drag than early studies of forward-angled wing design had suggested, the enormous flight envelope of the aircraft definitely proved a great deal.
An X-29 being flown at high alpha to investigate votex control.
Build your own X-29
Thankfully, your X-29 doesn't have to cost millions of dollars. You can scratch build your own with our free plans or buy a speed build kit from our store. Like the real thing, this foam board RC aircraft boasts some fantastic performance.
If you haven't already, here's our video of the X-29 being put through its paces by Josh and Andres. It can be built as a simple pusher prop or as an advanced EDF.
Head on over to the Flite Test store to check out all of our kits!
Article by James Whomsley
Editor of FliteTest.com
www.youtube.com/projectairaviation
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