MIT and NASA researchers have developed a morphing airplane wing that goes back to the future: The entire wing bends and twists, much as the Wright brothers’ Flyer 1 did more than a century ago. Rather than wires and pulleys to reshape canvas-covered wood pieces, this wing uses a high-strength foil on an aluminum frame.
The new composite wing would do away with weight and complexity of flaps and ailerons. MIT believes such a wing would weigh one-tenth as much as a conventional aircraft wing. Testing is already under way on small remote-control aircraft.
Writing in the journal Soft Robotics, the MIT engineers outlined a “lightweight, high-performance elastic wing that controls flight maneuvers by flexing its entire surface.” The wing is covered with Kapton foil, a film that resists extreme heat and cold and is already used in flexible printed circuits and thermal blankets on spacecraft and satellites. The foil is layered like fish scales on the wings and the individual elements slide across each other as the wing flexes.
Two small motors twist each wingtip while in flight. That allows the overall wing to change shape to reduce drag, increase the stall angle (to change the amount of lift), and reduce vibration. For the test, the morphing wings were configured to use the twisting process to replace the ailerons and flaps.
The MIT report says manufacturing would be simpler than traditional (usually) aluminum, let alone the composite wings (as on the Boeing 787) that requires large, costly equipment. Specialized robots would build the morphing wings from small, lightweight subunits. Miniature robots would crawl atop or inside the wing structure to assemble the pieces. MIT has already developed prototype robots for wing-building, but the current test wing was hand-assembled.
The same robot would do periodic inspections to long for damaged segments. The repair would involve removing and replacing only the damaged segments.
Neil Gershenfeld, director of MIT’s Center for Bits and Atoms (CBA), says, MIT’s morphing wing wasn’t the first attempt since the Wright brothers did it in 1903. The in-between attempts used heavy mechanical control structures that cancelled out any efficiencies gained from a smoother exterior wing surface. Instead, “We make the whole wing the mechanism,” Gershenfield says. “It’s not something we put into the wing.”
The wings are first on the MIT project list. Later, the entire airframe (the fuselage) could be assembled similarly.
The first field applications might start with drones. Already light, the drones could be made lighter still and require less fuel to stay aloft. Some might be able to harvest enough energy from the sun that electric drones could fly overnight on the daytime harvest of solar energy.
MIT believes the same technology could be applied to devices where extreme flexibility is important. Imagine, for instance, a robot whose arm is continuously flexible, not just just at the joints.
Other possibilities: flexible windmill blades, bridges (they flex already and designers have to make allowances for that), and skyscrapers.