Shape-changing wings inspire more efficient aircraft designs

Shape-changing wings inspire more efficient aircraft designs
Computer simulation of a wing flex module
Computer simulation of a wing flex module
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Computer simulation of a wing flex module
Computer simulation of a wing flex module

We tend to think of aeronautical engineering as having left the birds standing still sometime around the First World War, but since jet fighters can’t perch and quadcopters can’t snag salmon out of a stream, we still have a few things to learn. Taking a couple of pages from the avian playbook, the Fraunhofer Institute for Electronic Nano Systems (ENAS) and its partners are developing wing flaps for airplanes that change shape like a bird’s wing for greater efficiency.

Billions of people take to the air every year with even greater numbers projected for the foreseeable future. Not only is this part of one of the greatest on-going transportation revolutions in human history, but also poses grave problems in terms of energy and pollution. One major goal of modern aeronautical engineering is to find ways to make jet aircraft more efficient in terms of the amount burned because, on a global scale, even the smallest reduction can have very large economic and environmental benefits.

The Fraunhofer consortium’s project is part of Europe’s Smart Intelligent Aircraft Structures (SARISTU) program, which aims at a reduction of jet fuel by six percent. In this case, the strategy is to redesign the jet aircraft’s wing so it’s more like that of a bird. That doesn't mean we’ll be seeing 747s with feathers, but rather with wing sections that can alter their shape and so the flow of air over them, much in the same way as birds can spread or twist their feathers to give them the most lift in a desired situation.

In particular, the consortium is looking at a morphing flap. Modern wings have a very limited ability to change their shape, usually restricted to extending large, rigid landing flaps. “Landing flaps should one day be able to adjust to the air flow and so enhance the aerodynamics of the aircraft,” says Martin Schüller, researcher at the Fraunhofer Institute for ENAS.

Essentially, what the Fraunhofer engineers (and others working on shape-shifting wing systems like Flexsys) are doing is going back to Day One of the age of flight. When the Wright brothers took off from Kitty Hawk in 1903, their flyer didn't have flaps and ailerons, Instead, they used what was called “wing warping,” where lines and pulleys twisted the wing, so the air flowed in the desired manner. The morphing flap takes a high-tech approach to this.

It works by means of a mechanism that alters the shape of the flap under the control of a computer algorithm. The skin of which is made up of alternating hard a soft areas consists of a silicon skin with the flexible parts made of a elastomeric foam that stays pliable even down to minus 80⁰ C (minus 112⁰ F). Since this is still very much in the experimental stage, Fraunhofer isn’t keen to divulge too many technical details

Fraunhofer and its partners have built four prototypes that are 90 cm (35.4 in) long. Two of these are covered in skin. These will be used for engineering and wind tunnel testing, and will be on display at the ILA Berlin Air Show until May 25.

Source: Fraunhofer

"...even the smallest reduction can have very large economic and environmental benefits..." - no it can not.
6%, which is itself not a "smallest reduction" anyhow, is still stuff-all in the grand scale of things. If your business relies on 6% to stay profitable, you're dicing with bankruptcy, and it makes not a squat of difference to the environment if our planes burn 6% slower - it's only going to take a week or so before that 6% is consumed by more planes and flights anyhow.
Exactly. In aviation industry fuel cost is a significative fraction of business running cost, and with low margin a 6% reduction in fuel consumption can make the difference between going bust and stay profitable.
Anywy, 6% fuel burning reduction is a big deal in commercial aviation ! I thougt Boeing 787 Dreamliner's wingtips was already in some of this flexible shape ?
A 747 uses a gallon of fuel a second, over a 6 hour flight that's 21600 seconds. 6% is 1296 gallons. With the cost of fuel of $5.50 that's $7,128 savings for the flight. With 500 people on the plane it's only about $14/person but it's still more money than the crew (of 12) on the plane makes.
Some industries run on pretty thin margins so 6% can matter but I'm sure there are tradeoffs not factored in to that number.
The article says "Modern wings have a very limited ability to change their shape, usually restricted to extending large, rigid landing flaps." That's true, and also a pity -- the original Wright Flyer of over a century ago used a technique known as Wing Warping to change the shape of the airfoil. For construction techniques of the time, using hinges and solid sections (ie: ailerons and flaps) quickly turned-out to be more reliable, easier to construct, and easier for pilots to control. Materials and early technical problems steered generations of aeronautical engineers. But, it's refreshing to see the latest materials are helping to make wing warping and smooth morphing of control surfaces practicable. Everything old is new again.