NASA researchers recently subjected a new wing design, which appears long and thin with a lightweight structural design, to a series of grueling tests to find its structural limits. What they found encouraged them about the wing’s potential, even as they pushed it beyond its intended limits.

The 15-foot Structural Wing Experiment Evaluating Armor Reinforcement (SWEET-15) test article is part of NASA’s research to develop future ultra-efficient aircraft. The design incorporates a long wing supported by an aerodynamic strut, based on NASA’s earlier Transonic Truss-Braced Wing concept.

The research team is working to understand whether SWEET-15’s design and its new lightweight structural designs could help commercial airliners save fuel. But first, they need to understand how it behaves under the types of forces that wings experience in flight.

The SWEET-15 design originated from combining five different advanced composite manufacturing and assembly technologies that enabled the novel structural design. The 15-foot-long test article was then designed and manufactured at NASA’s Langley Research Center in Hampton, Virginia, before traveling to NASA’s Armstrong Flight Research Center in Edwards, California, for testing.

For several months, NASA engineers intentionally bent the test wing at NASA’s Armstrong Flight Loads Laboratory. Numerous stress and load sensors, including fiber optic stress sensors, were placed throughout the structure to track how the wing responded as forces increased.

The sensor data confirmed predictions made by NASA computer models. According to initial findings, the wing withstood the expected in-flight forces without problems. The results provided the team with confidence in new approaches and manufacturing methods for connecting the wing parts used on SWEET-15, which could support future efficient aircraft designs. The manufacturing approach, developed at NASA Langley using the Advanced Composites Integrated Structural Assembly Robot, aims to produce lighter, stronger composite structures for aerospace vehicles.

The test concluded with a deliberate test to failure, in which engineers increased loads beyond the wing’s design limits to determine how and where it would fail. The structure ultimately failed at approximately 127% of its design limit load, with visible damage appearing near the trailing edge of the wing and on the upper wing deck. This test item provided valuable information about how the joints connecting the wing to its primary strut and a secondary strut, called the jury strut, behave under forces beyond the expected flight envelope.

This is the first time that a representative reinforced-frame composite wing configuration has undergone this type of structural evaluation. This was only possible thanks to NASA’s collaboration between centers and projects, in which researchers used agency resources, such as the fiber optic detection system developed to collect data on both aircraft and spacecraft.

To prepare for testing, NASA Langley engineers designed, analyzed and manufactured the wing and completed safety preparations and laboratory setup.

Researchers will now analyze data collected during testing to inform future aircraft designs and support NASA’s ongoing efforts to develop more efficient aviation technologies.

The work is being carried out through NASA’s Subsonic Flight Demonstrator project in the agency’s Research Technology Mission Directorate. The successful testing of multiple innovative components marks a milestone in NASA aeronautical research.

For more information, visit:

https://www.nasa.gov/aeronautics/