The cellular wing structure was designed so that the core of the wing has a different geometry with more struts and lattice elements per unit volume than other areas, making it denser and stiffer than more sparse areas. This varied geometry, which creates some stiff areas and some flexible areas, enables the wing to be twisted (or deformed) as one piece with just a small motor on each wing tip, while staying very stiff in span-wise bending. This ability to morph the entire wing eliminates the need for multiple wing flaps and their heavy actuating systems, further reducing weight and decreasing drag. It is also reminiscent of the first airplanes with wood and canvas wings that were manipulated as one unit using cables and levers
“Our system opens up a whole new avenue of returning to the origins of aircraft, thinking less about mass sensitive actuation systems and thinking of an aircraft as one giant, deformable structure,” says Jenett.
The next version, MADCAT V1, which is scheduled for wind tunnel testing in July, will increase the wingspan from four to 14 feet – almost the size of a small passenger aircraft. It is constructed from over 2,000 injection-molded GFRP parts for fast production – up to 10,000 parts a week. Jenett says that while GFRP is sufficient for current testing, researchers will return to CFRP at a later point for higher performance. In another nod to speed, the V1’s parts are being attached using nuts and bolts, which allows researchers to build structure volume quickly.
Ultimately, Jenett says that researchers at the CBA and NASA would like to design integral, bi-stable connectors that can be injection molded on the part or added as a secondary step before assembly. This would eliminate the need for the millions of fasteners found in modern aircraft like the Boeing 737. “So, you wouldn’t have any fastener hardware,” Jenett explains, “You would just click the pieces together like Lego bricks, but they would be structural.”
Later, MADCAT V1’s parts may be assembled by small, simple robots. Jenett and the NASA team are currently experimenting with several prototypes of 12-inch or smaller robots that can crawl along and through the structure, return for parts and continue to build the lattice structure.
Ultimately, the combination of small, modular composite parts and discrete assembly using lattice-building robots has the potential to revolutionize aircraft manufacturing.
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