Bell has just released a video showcasing its High-Speed Vertical Takeoff and Landing (HSVTOL) technology in action. The two-minute clip demonstrates a ground test of the nacelle system used to lift and land a VTOL X-plane before converting to jet flight as part of DARPA’s Speed and Runway Independent Technologies SPRINT X-plane program.
The tests carried out at Holloman Air Force Base in New Mexico are aimed at showcasing how a rotorcraft can transition from rotor-propelled lift-off to jet-propelled horizontal high-speed flight. The video shows the turbine-powered rotors on a track-mounted test bed powering up and applying thrust as they would in a takeoff situation similar to what one would see in a tiltrotor craft like the Osprey.
As the craft reaches sufficient speed, the jet propulsion system is supposed to take over, but this means that the rotors become nothing more than a liability, acting like brakes as they increase drag. To prevent this, the rotors are designed to feather and then fold back and lock into place.
When fully developed, the new pilot-optional aircraft is expected to be able to cruise at high subsonic speeds of up to 450 knots (518 mph, 833 km/h) for a range of 200 nm (230 miles, 370 km) at altitudes up to 30,000 ft (9,100 m) while carrying payloads of up to 5,000 lb (2,300 kg) in a compartment large enough to hold a small vehicle. The purpose of the craft will be to provide runway independence for missions ranging from special forces insertion to disaster relief in inaccessible areas.
“The successful sled test completion is a culmination of Bell’s HSVTOL research and unprecedented technology development,” said Jason Hurst, Executive Vice President, Engineering. “The technology demonstration provides Bell with critical experience and knowledge that will inform our X-plane development for DARPA’s SPRINT program. It is