NASA’s Subsonic Research Aircraft Testbed (SCRAT) is a modified Gulfstream III used for the ACTE flexible-flap research project. (NASA Photo)

NASA has conducted a series of flights investigating the benefits of twistable, flexible wing flaps to improve flight efficiency. The Adaptive Compliant Trailing Edge (ACTE II) flights investigated the ability of shape-changing surfaces to determine if advanced flexible trailing-edge wing flaps can both improve aircraft aerodynamic efficiency, and reduce airport-area noise generated during takeoffs and landings.

The flight featured the flap set in such a way that different areas of the flap were deflected in different positions. The purpose of this flight was to demonstrate the ability to fly with a twisted configuration. The potential advantage of such a configuration is the ability to change where the center of lift is on the wing, such as how and where the wing responds to wind gusts. Accomplishing this can lead to future wing designs that are much lighter, making the aircraft more efficient.