The transportation sector has been scrambling to decarbonize air travel and the latest twist is, well, a twist. A NASA-backed team at the Massachusetts Institute of Technology has come up with a flexible aircraft wing that could cut fuel consumption by reducing weight and improving aerodynamics.
To ice the cake, the interior of the wing is designed to be constructed by teams of tiny robots working in concert, and it would be covered by a biomimicry skin similar to scales or feathers.
Mighty Morphin Power Wings
The journal Soft Robotics has the full scoop on the project. If you don’t have time for all the details, our friends over at NASA’s media office — who may have grown up watching Kyōryū Sentai Zyuranger — have a recap under the title, “Go, Go, Green Wing! Mighty Morphing Materials in Aircraft Design.”
As described by NASA, the problem with conventional, rigid aircraft wings is that they are “only a compromise.” Wing flaps aside, their fixed shape does not provide for maximum fuel efficiency at various stages of flight:
The best shape in any moment depends on many factors: how much the aircraft weighs, the speed it is flying, and whether the pilot wants to climb higher or descend, for instance.
The next time you fly check out the wing action and see how little of the surface is capable of changing position, and you can see how there’s plenty of room for improvement (if you spot something else out there, don’t pull a Bob Wilson).
The new wing represents a sea change in aircraft design. Instead of big parts welded together, the whole thing is made from small building blocks made out of next-generation carbon fiber composite:
These building blocks are assembled into a lattice, or arrangement of repeating structures; the way that they are arranged determines how they flex. The wing also features actuators and computers that make it morph and twist to achieve the desired wing shape during flight.
Btw “actuator” is fancyspeak for the mechanism that makes a part move in a robot or other device.
NASA provides a wordier explanation at its MADCAT (Mission Adaptive Digital Composite Aerostructure Technologies) page:
The MADCAT demonstrator utilizes a wing-twist actuation mechanism that generates a linear span-wise wing-morphing capability, thereby producing both lateral and longitudinal directional control authority. In addition, the aerodynamic lift/drag can be modulated by varying wing-tip twist oscillation frequency.
The Age Of Digital Manufacturing
The new technology was inspired by the Wright brothers pioneering work in flight, which depended on primitive actuators (wires and pulleys) to bend the wings of their aircraft into the desired shape.
You can file it all under D for “deforming,” an aircraft wing design concept aimed at enabling in-flight shape shifting. The aim is to seamlessly change shape, or deform, a wing to achieve “pure lift and role.”
As described by MIT, earlier attempts at wing deformation were focused on building mechanical units into the wing. That had the opposing effect of adding weight and complexity to the structure.
The NASA/MIT approach goes like this:
In the team’s new approach, the whole shape of the wing can be changed, and twisted uniformly along its length, by activating two small motors that apply a twisting pressure to each wingtip.
The individual pieces are strong and stiff, but the exact choice of the dimensions and materials used for the pieces, and the geometry of how they are assembled, allow for a precise tuning of the flexibility of the final shape.
The principle is based on the use of Lego-style units called “digital materials.” As with Lego, from a few basic units you can construct larger forms with an infinite variety of shapes and sizes. Here’s a closeup of the new wing:
If you’ve seen robots build brick walls, you can see where this is going. The digital approach to aircraft wing construction enables the use of a robotic manufacturing process that could result in lower costs.
The cost savings could travel through the whole lifecycle of the wing, including repairs, maintenance and eventual dis-assembly and re-use of materials.
According to MIT, initial wind tunnel tests have demonstrated that the new wing is on par with conventional wings in terms of aerodynamics and it has about 1/10 the weight.
The team has also advanced to the stage of flying an unmanned aircraft with the new wings. According to both NASA and MIT, the pilot reported that the demonstrator handled just as well as a conventional craft.
The next steps include equipping the demonstrator with advanced video recording and sensing equipment.
The digitization of manufacturing and construction dovetails with the 3-D printing/advanced manufacturing movement, so the team foresees that a similar approach could pop up in many other fields, including wind turbine manufacturing and construction, buildings, and spacecraft.
Images: NASA/Kenneth Cheung via MIT.