Bell Textron Inc. has completed wind tunnel testing at the National Institute for Aviation Research (NIAR) at Wichita State University in support of the DARPA Speed and Runway Independent Technology (SPRINT) program. This test phase follows successful evaluation of the Stop/Fold rotor system using the Holloman High Speed Test Track (HHSTT) in New Mexico in 2023.

Building upon the previous folding rotor testing, the wind tunnel program validated the stability and control of the aircraft through the rotor fold and unfold sequence in flight. Together, these two critical risk reduction tests prove the concept is ready to move ahead into a flight demonstration as part of the DARPA SPRINT program.

“After completing folding rotor transition testing on the sled at Holloman Air Force Base last year, we’re thrilled to have now completed this next phase of testing,” says Jason Hurst, executive vice president, Engineering, Bell. “Bell’s advanced Stop/Fold family of systems will revolutionize the speed, range and survivability of vertical lift aircraft to enable operations in contested environments. We are excited to be part of another aviation milestone with this breakthrough technology."

Bell is currently in Phase 1B of the DARPA SPRINT program. The SPRINT program intends to design, build and fly an experimental aircraft (X-Plane) to demonstrate enabling technologies and integrated concepts necessary for a transformational combination of aircraft speed and runway independence for the next generation of air mobility and air combat platforms.

Bell's scalable Stop/Fold configurations combine modern jet speed with runway independence, offering next-generation capabilities that will transform the battlefield for the nation's warfighters. The ability to leverage available runways for maximum payload and range, along with robust vertical lift, empowers Agile Combat Employment (ACE) from nearly any location - delivering a clear strategic advantage, particularly in the Indo-Pacific theater. In an environment with limited runways, vast distances, and a contested battlespace, this aircraft provides the essential speed and range to meet mission demands. This unique combination of capabilities is also ideally suited for Special Operations, enhancing speed, reach, and survivability for the most challenging and sensitive missions.