Bell Textron 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.

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 is one of two companies currently working on designs as part of Phase 1B of SPRINT, the other being Aurora Flight Sciences, a Boeing subsidiary.

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.

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.

Bell first unveiled design concepts for new aircraft systems for military applications which would use Bell’s High-Speed Vertical Take-Off and Landing (HSVTOL) technology in 2021. HSVTOL technology blends the hover capability of a helicopter with the speed, range and survivability features of a fighter aircraft. The Stop/Fold concept is intended to offer vertical takeoff and landing capability, as well as the ability to hover, but with a tilting rotor system that can be stowed in a lower-drag configuration to allow for higher-speed level flight. A separate traditional jet propulsion system provides forward thrust in the latter mode.