Bell has tested a propulsion system that uses a rotor for vertical take-off and landing and transitions to using a jet engine for high speed horizontal flight on a sled track at Holloman Air Force Base, New Mexico.
The High-Speed Vertical Takeoff and Landing (HSVTOL) technology concept is being developed for DARPA’s SPRINT (SPeed and Runway INdependent Technologies) program, launched last year.
The SPRINT program is the latest US-effort at designing, building and flying an experimental aircraft, an X-plane, that can fly horizontally at high speed while retaining the flexibility and “runway independence” granted by a helicopter – a HSVTOL.
Bell tested the high- and low-speed transitions of its HSVTOL concept using a rig fixed to a sled on the US Air Force’s Holloman High Speed Test Track, which is usually used to test missiles.
During the test runs the rotor stops and folds into the nacelle while a jet engine takes over, a process that would happen in mid-air and has never been tested before.
The tests advanced the transition method to Technical Readiness Level (TRL) 5 said Bell.
Jason Hurst, executive vice president engineering at Bell said, “The successful sled test completion is a culmination of Bell’s HSVTOL research and unprecedented technology development.
“The technology demonstration provides Bell with critical experience and knowledge that will inform our X-plane development for DARPA’s SPRINT program. It is a pivotal step in the creation next generation of high-speed vertical lift aircraft for future warfighters.”