Wind Over Its Wing: NASA's X-66 Model Tests Airflow

NASA's Sustainable Flight Demonstrator (SFD) project recently concluded wind tunnel tests of its X-66 semi-span model in partnership with Boeing. The model, designed to represent half the aircraft, allows the research team to generate high-quality data about the aerodynamic forces that would affect the actual X-66.

Test results will help researchers identify areas where they can refine the X-66 design - potentially reducing drag, enhancing fuel efficiency, or adjusting the vehicle shape for better flying qualities.

Tests on the Boeing-built X-66 semi-span model were completed at NASA's Ames Research Center in California's Silicon Valley in its 11-Foot Transonic Unitary Plan Facility. The model underwent tests representing expected flight conditions so the team could obtain engineering information to influence the design of the aircraft's wing and provide data for flight simulators.

Semi-span tests take advantage of symmetry. The forces and behaviors on a model of half an aircraft mirror those on the other half. By using a larger half of the model, engineers increase the number of surface pressure measurements. Various sensors were placed on the wing to measure forces and movements to calculate lift, drag, stability, and other important characteristics.

The semi-span tests follow earlier wind tunnel work at NASA's Langley Research Center in Hampton, Virginia, using a smaller model of the entire aircraft. Engineers will study the data from all of the X-66 wind tunnel tests to determine any design changes that should be made before fabrication begins on the wing that will be used on the X-66 itself.

The SFD project is NASA's effort to develop more efficient aircraft configurations as the nation moves toward aviation that's more economically, societally, and environmentally sustainable. The project seeks to provide information to inform the next generation of single-aisle airliners, the most common aircraft in commercial aviation fleets around the world. Boeing and NASA are partnering to develop the X-66 experimental demonstrator aircraft.