NASA is at it again, and literally reaching for the stars with their latest technological development, known as Shape Memory Alloy. The material can allow aircraft wings to fold controllably to different angles in flight, without the need for heavy conventional motors or hydraulic systems.
In a recent flight series, as part of the Spanwise Adaptive Wing Project (SAW), which took place at the agency's Armstrong flight research centre in California, the advancement was successfully tested.
"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 have 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."
The SAW project is a joint development between Armstong, NASA's Glenn research centre in Cleveland, Langley research centre in Virginia, Boeing research & technology, and Area-I inc. The benefits of this, as proved in the flight testing, will aid future subsonic and supersonic aeroplanes by reducing weight (estimated 80% less), fuel economy, and speed.
Furthermore, the Shape Memory Alloy offers increased controllability, with testing moving the wings between zero and 70 degrees up and down in flight. Following the success of SAW thus far, NASA plans to test the new technology on the wings of an F-18 soon.
"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."
"We put the SAW technology into a real flight environment, and these flights not only proved that we can fly with this technology, but they validated how we went about integrating it," commented Moholt. "We will use the data from these flights to continue to improve upon the actuation system, including speed and smoothness of actually folding the wings, and we’ll apply them as we get ready to fly again in 2018."
In the meantime, you can have a look at the video below to see the SAW technology in action: