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April 3, 2019
Composed of hundreds of small, identical pieces, the shape-shifting wing can automatically morph to the most efficient shape for a given stage of flight.
Image Credits: NASA Ames Research Center/Eli Gershenfeld
NASA is no stranger to transforming aircraft. Consider the ten-engine drone called Greased Lightning, which can shift from VTOL into cruise mode in midflight.
A new project from NASA and MIT explores shape-shifting aircraft further, but from a distinctly different direction. This new wing technology, made up of hundreds of identical pieces, is the foundation for aircraft with flexible wings that transform dynamically in flight to create the optimal shape for their moment-to-moment flight conditions.
Outlined in the journal Smart Materials and Structures, and by MIT News, the approach involves building one wing surface out of a series of injection-molded structures made of polyethylene resin, which are coated with a layer of polymer material. This creates a lightweight and flexible structure that could be morphed and changed in flight. By tweaking the flexibility of specific structures in specific locations, researchers could dial in the wing's response to airflow conditions so it automatically would transform into an ideal aerodynamic shape for the various stages of flight, such as takeoff and cruising.
Image Credits: NASA Ames Research Center/Kenny Cheung
As research engineer Nicholas Cramer at NASA Ames, the paper's lead author, explains in MIT News: "We’re able to gain efficiency by matching the shape to the loads at different angles of attack. We’re able to produce the exact same behavior you would do actively, but we did it passively.”
Researchers tested a hand-constructed model in NASA's Langley Research Center wind tunnel. Eventually, they hope, robots could take on the construction dirty work. And given that the design is modular and the structural subunits are cheap to produce, the approach could also make it much easier to prototype unusual but perhaps more aerodynamically efficient wing designs.
Sensory Networks
MADCAT also uses new sensory systems developed to give real-time feedback on airflow around a wing, for both testing and in-flight purposes.
Each wing is equipped with a series of sensors taking in real-time data from the surroundings. Usually, this kind of network will have each sensor send back raw data, leaving significant lag and processing time.
Image above: An individual voxel used for the MADCAT project. Image Credit: NASA.
Instead, the system designed for MADCAT groups sensors in the skin of the wing around nodes— small data collection centers. Once the data is gathered, it is processed and passed along to a neighboring node. These work together like a funnel, with each set of sensors taking in data and combining it with its neighbors’, sending information – rather than unprocessed raw data – to the next stage. In other words, the sensors don’t just pass along recorded values – they say what those values actually mean, and can report and interpret airflow patterns in real time, adjusting the structure of the plane’s wing accordingly.
Modeling a Mid-Sized Plane
The final testing phase for MADCAT has successfully completed, significantly increased from its original demonstration as an adaptive drone at the one-meter scale. Recent testing has proven the scalability of this model, using MADCAT to develop a mid-sized plane with a 14-foot wing span with even fewer types of parts than the original model.
NASA Designs Ultra-light Wings That Change Shape During Flight
This combination of adaptive algorithms, lightweight materials and modular design all make the MADCAT wing a unique technology with the potential to revolutionize air vehicle designs. The project has proven modular ultralight wing design can work on a large scale. As this technology continues to develop and make its way into industry, our planes will become not only more cost effective in their design, construction, and repairs, but increasingly versatile, able to adapt to changing weather conditions or scientific objectives on the fly. MADCAT is forging the path to a smarter, greener and more efficient aviation future.
Related article:
What is MADCAT?
https://www.nasa.gov/feature/ames/madcat
Related links:
MIT News: https://phys.org/news/2019-04-mit-nasa-kind-airplane-wing.html
Smart Materials and Structures: https://iopscience.iop.org/journal/0964-1726
NASA Ames Research Center: https://www.nasa.gov/ames
Images (mentioned), Text, Credits: Popular Mechanics/Eric Limer.
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