Boeing has proposed focusing NASA’s Sustainable Flight Demonstrator project on long, thin-wing technology, halting the company’s work on the X-66 flight demonstrator, the centerpiece of the project aimed at developing more sustainable commercial airliners.
The current X-66 aircraft adopts a transonic truss-braced wing concept that uses thin-wing technology. Under Boeing’s proposal, the project will prioritize research on the technology, which Boeing identified as having broad applications for potential incorporation into aircraft with and without truss braces, while keeping research into the transonic truss-braced wing concept, NASA said.
The company made the recommendation based on data gathered since the Sustainable Flight Demonstrator research began in 2023 under the Space Act Agreement.
X-66 as Testbed for Boeing 737 Replacement
Besides supporting NASA’s goal to achieve substantial improvements for next-generation airliner efficiency, Boeing plans to use the X-66 to inform the design of a single-aisle replacement for the 737 in the 2030s, Aviation Week Network reported. According to Boeing, the proposed changes in the project will not substantially affect the development of the new aircraft.
While the new approach is being evaluated and the project is on pause, the company reallocated engineers from the experimental program to the 777X and 737 Max development effort ahead of the 2026 delivery schedules.
