Shape-Shifting Wing Design Prepares For Testing

First, fuel savings. Next? Maybe a whole new way to use wings.

For over a century, airplane wings have used flaps to alter their shape for better flight performance: extending to generate more climb during takeoff, tilting to stall and generate more breaking power during landings, and staying neutral during normal flight. Yet flaps, as discrete parts, are imperfect, letting air through gaps or catching more air than necessary during flight, and leading to inefficiencies, which in turn lead to higher fuel costs. FlexFoil, an appropriately named flexible wing technology by similarly subtly named company FlexSys, is a seamless flexible wing that can work like flaps but doesn't have the accompanying inefficiencies that come with being a physically separate part.

The concept is explained in "Mission Adaptive Compliant Wing – Design, Fabrication and Flight Test," a 2006 research paper, whose lead author, Sridhar Kota, is the founder of FlexSys. In this system, the strain placed upon the structure (here, a wing) is distributed through the whole of the structure, in a similar way to how multiple cables attached to a few towers support the whole of a suspension bridge. What is special about this system is that, unlike the cables on the bridge, the strands can deliberately be pulled and warped, thanks to the elastic nature of the connections and their distribution throughout the wing. Servos and actuators inside the wing pull the strings, and all of this is controlled and coordinated by a computer algorithm, which interprets the pilots commands and bends the wing accordingly.

The boring yet practical promise of this technology is more fuel-efficient airplanes, with projected fuel savings of up to 8 percent for airplanes with wings converted to FlexFoil, and in theory as high as 12 percent on airplanes designed with the technology in mind. What makes this way more interesting than just minor fuel savings is the new ways a flexible wing could be used, allowing more control options for wing edges than just extending or pivoting up and down.

In order for that new future to be realized, the wings will first have to complete testing. FlexSys intends to test the new wing technology on a converted Gulfstream jet in July of 2014.