Bell Textron Inc., a subsidiary of Textron Inc., has completed wind tunnel testing at the National Institute for Aviation Research (NIAR) at Wichita State University, validating the Stop/Fold rotor technology as part of the DARPA Speed and Runway Independent Technology (SPRINT) program.
The milestone follows previous tests conducted at the Holloman High Speed Test Track in New Mexico, which assessed the rotor system’s folding capability during high-speed transitions.
The wind tunnel program confirmed the aircraft’s stability and control throughout the rotor fold and unfold sequence in flight. These results mark a major step forward for the Stop/Fold rotor system, demonstrating its readiness for the next phase: flight demonstrations under 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,” said Jason Hurst, executive vice president of Engineering at 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’s Stop/Fold technology integrates modern jet speeds with the flexibility of vertical lift, providing runway independence and enhancing Agile Combat Employment (ACE) capabilities. The scalable design is expected to transform air mobility and combat platforms by combining increased speed and range with the ability to operate from nearly any location. This capability is particularly critical for the Indo-Pacific theater, where limited runways, vast distances, and a contested battlespace demand innovative solutions.
The SPRINT program, currently in Phase 1B, aims to design, build, and fly an experimental X-Plane that showcases enabling technologies for next-generation air mobility. Bell’s Stop/Fold system is central to this effort, offering unparalleled speed and runway-independent operations. The technology also enhances operational effectiveness for Special Operations, improving speed, reach, and survivability for sensitive missions.
By successfully validating the Stop/Fold rotor system in wind tunnel testing, Bell continues to lead the way in developing revolutionary aviation technologies that meet the evolving needs of modern warfare. The completion of this testing phase positions the technology for a flight demonstration, paving the way for its eventual deployment in real-world operations.