Foldable wings could result in more efficient supersonic flight
01 February 2018
NASA has successfully tested a new material at its research centre that will allow aircraft to fold their wings to different angles whilst in the air.
The test, which took place at NASA’s Armstrong Flight Research Centre, was part of the Spanwise Adaptive Wing project (SAW). The project brings together Armstrong, NASA’s Glenn Research Centre, or GRC, Langley Research Centre, Boeing Research & Technology and Area-I Inc. and aims to validate the use of a lightweight material that can fold aircraft wings.
The material is called shape memory alloy and is built into an actuator on the aircraft where it can fold the outer portion of an aircraft’s wings in flight without the use of a heavy hydraulic system. Systems using this material could weigh up to 80 percent less. It works by using thermal memory in a tube to move, functioning much like an actuator. Once heated, the alloy conducts a twisting motion in the tubes, which moves the wing’s outer portion up or down.
The recent test demonstrated the material’s ability, by folding the wings between zero and 70° up and down in flight. “We wanted to see: can we move wings in flight, can we control them to any position we want to get aerodynamic benefits out of them, and could we do it with this new technology,” said SAW Co-Principal Investigator Othmane Benafan. “Folding wings has been done in the past, but we wanted to prove the feasibility of doing this using shape memory alloy technology, which is compact, lightweight, and can be positioned in convenient places on the aircraft.”
One of the main benefits of foldable wings is in supersonic flight. “There’s a lot of benefit in folding the wing tips downward to sort of ‘ride the wave’ in supersonic flight, including reduced drag. This may result in more efficient supersonic flight,” SAW Principal Investigator Matt Moholt said. “Through this effort, we may be able to enable this element to the next generation of supersonic flight, to not only reduce drag but also increase performance, as you transition from subsonic to supersonic speeds. This is made possible using shape memory alloy.”
NASA Glenn, which developed the initial alloy material, worked closely with Boeing to be able to use the alloy with an actuator in flight.
“The performance of this new alloy that we developed between NASA and Boeing really showed outstanding performance,” said Jim Mabe, Technical Fellow with Boeing Research and Technology. “From the time we started initial testing here at Boeing, up to the flight tests, the material behaved consistently stable, and showed a superior performance to previous materials.”
Video courtesy of NASA Armstrong Flight Research Centre