Aircraft

NASA tests aircraft with shape shifting wings

NASA tests aircraft with shape...
The Adaptive Compliant Trailing Edge (ACTE) flap undergoing testing at NASA’s Armstrong Flight Research Center at Edwards Air Force Base, California (Image: NASA/Ken Ulbrich)
The Adaptive Compliant Trailing Edge (ACTE) flap undergoing testing at NASA’s Armstrong Flight Research Center at Edwards Air Force Base, California (Image: NASA/Ken Ulbrich)
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The Adaptive Compliant Trailing Edge (ACTE) flap undergoing testing at NASA’s Armstrong Flight Research Center at Edwards Air Force Base, California (Image: NASA/Ken Ulbrich)
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The Adaptive Compliant Trailing Edge (ACTE) flap undergoing testing at NASA’s Armstrong Flight Research Center at Edwards Air Force Base, California (Image: NASA/Ken Ulbrich)
This modified Gulfstream III used as a test bed for the ACTE flexible-flap research (Image: NASA)
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This modified Gulfstream III used as a test bed for the ACTE flexible-flap research (Image: NASA)
FlexSys ACTE flap (Image: FlexSys)
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FlexSys ACTE flap (Image: FlexSys)

In January, we looked at FlexFoil; a variable geometry airfoil system that seamlessly integrates into the trailing edge of the wing. During the year the system has made the leap from the test bench to the sky, with NASA conducting tests of the FlexFoil on a modified Gulfstream III business jet.

For all the advances in aircraft design over the last century, the wings of an airplane are still fundamentally clumsy. If airplanes spent all their time flying straight and level, the airfoils would only need to be one shape, but that's not how it works – they need to turn and blank, ascend and descend, stay in the air at different speeds, and go through all that tedious taking off and landing.

In a conventional wing, changing shape is achieved by equipping the wing with flaps that pivot, slide, and generally rely on mechanics that create all sorts of seams and gaps. These not only make the wing less efficient, but also noisier.

FlexSys ACTE flap (Image: FlexSys)
FlexSys ACTE flap (Image: FlexSys)

NASA’s Environmentally Responsible Aviation (ERA) project aims at making airplanes quieter and more fuel efficient. One aspect of this is the FlexFoil, made by Ann Arbor, Michigan-based FlexSys and developed as part of NASA and the U.S. Air Force Research Laboratory’s (AFRL) Adaptive Compliant Trailing Edge (ACTE) project.

Put simply, FlexFoil is a shape-changing assembly that replaces the flaps on a wing and can alter shape in flight to produce seamless bendable and twistable aerofoil surfaces. This allows the FlexFoil to act like a flap in its various positions while still providing an unbroken air surface. This makes for a more streamlined wing and reduces noise during takeoffs and landings. Importantly, it’s designed not only for new aircraft designs, but for retrofitting to existing ones.

The ACTE flights were carried out at NASA's Armstrong Flight Research Center in Edwards, California, using the Gulfstream III as a testbed with the composite material FlexWing replacing both of the aircraft’s 19-ft (5.7-m) aluminum flaps. The purpose of the test was to take it out of the wind tunnels and determine if its airworthy. The FlexFoil was locked in a series of shapes to allow engineers to collect data on its aerodynamic performance under real-life flight conditions.

This modified Gulfstream III used as a test bed for the ACTE flexible-flap research (Image: NASA)
This modified Gulfstream III used as a test bed for the ACTE flexible-flap research (Image: NASA)

NASA says that work continues on commercial applications for the FlexFoil as well as for those beyond aircraft wings. It is hoped that ACTE technology will allow engineers to tailor wings to particular purposes at the best efficiency and using much lighter materials.

"The first flight went as planned – we validated many key elements of the experimental trailing edges," says Thomas Rigney, ACTE Project Manager. "We expect this technology to make future aircraft lighter, more efficient, and quieter. It also has the potential to save hundreds of millions of dollars annually in fuel costs."

Source: NASA

7 comments
Deres
I think such complex system has a low effect on effeciency. In fact, the back of the wing is inside the turbulent part of the air and in the limit layer. I think this is why those ty^pe of system have been studied for a very long time but never adopted. They are marginaly more efficient but far more complex than classical systems of flaps. Nevertheless they can have many advantages in term of noises and stealth. In fact, continuity of the skin is very important for stealth properties. In stealth mode, most combat planes tends to limit manoeuvers and to not use their control surfaces too much.
Bob
The Wright brothers knew about wing warping and canards for control. Even the original pusher prop allowed a smoother airflow. Maybe the modern (educated) designers will someday catch up instead of just dabbling at progress. I know that flight has come a long way but the Wright brothers ideas were way ahead of their time.
Catweazle
So we're back to wing-warping again, are we? Funny how stuff goes round in circles...
John Birk
​Winglets ​were retrofitted to many older aircraft and now seem standard on most new aircraft, perhaps this will become the new retrofit and eventually standard on new aircraft? antiguajohn
ezeflyer
Bendable composites are used in such applications as archery bows. There is no mystery in this. It was bound to happen.
Nick Herbert
Hmmm, there I was, about to make a clever comment regarding wing-warping and I see that both Bob and Catweazle have beaten me to it...! Say no more.
Slowburn
I don't see it replacing multi-segmented flaps that increase the wing area.