Boeing illustration of the X-66 concept aircraft.

Boeing Jet to Demo NASA’s Sustainable Flight Concept

Aug. 21, 2023
An MD-90 single-aisle aircraft will be modified to test the Transonic Truss-Braced Wing design in development by NASA and Boeing, to validate new low-emissions technologies.

Boeing has delivered an MD-90 airplane to NASA in Palmdale, Calif., where it will be modified to test the Transonic Truss-Braced Wing (TTBW) configuration as part of NASA's Sustainable Flight Demonstrator project. Earlier this year NASA enlisted Boeing in a seven-year effort for a joint effort to build, test, and fly a full-scale demo aircraft and to validate new low-emissions technologies. NASA will invest $425 million, while Boeing and its partners are expected to provide an estimated $725 million for the Sustainable Flight Demonstrator project.

NASA maintains a laboratory and hangar for high-altitude research aircraft at the Los Angeles-area airport.

According to NASA, Sustainable Flight Demonstrator project involves industrial, academic, and other government organizations in partnership to identify, select, and mature airframe technologies – notably, new wing designs – that have a high probability of transition to future single-aisle commercial jets.

The MD-90 is a stretch version of the single-aisle, McDonnell-Douglas MD-80 aircraft. It has been adapted by Boeing as part of the X-plane series and is being further developed in collaboration with NASA and its Sustainable Flight Demonstrator program.

As a demonstrator aircraft, the jet has been designated as the X-66A. NASA calls it its “first experimental plane focused on helping the U.S. achieve its goal of net-zero aviation greenhouse gas emissions.” Further modification to the aircraft will begin soon, but ground and flight testing is expected to begin in 2028.

The TTBW concept foresees a single-aisle aircraft with thin but elongated wings, with diagonal struts that connect the wings to the fuselage for stability.

The expectation is that the wing structure will help to reduce fuel consumption by 8-10%. The demonstrator that Boeing and NASA will evaluate also will incorporate recent advances in propulsion systems, materials, and systems architecture.

Boeing earlier indicated it will incorporate other design elements from current aircraft in the demonstrator.

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