By David Szondy
July 13, 2025
https://newatlas.com/military/bell-gets ... r-x-plane/
Bell's revolutionary X-plane rotorcraft has received the green light to progress to the building and testing of a demonstrator aircraft. DARPA has down-selected the craft to move to Phase 2 of the agency's Speed and Runway Independent Technologies (SPRINT) program.
Rotorcraft such as the V-22 Osprey, with tiltable blades sitting on nacelles at the end of the aircraft's wings, have been around for decades, but DARPA's SPRINT program wants to push these to the next level by introducing a bit of Transformer's technology. A joint effort with the US Special Operations Command (SOCOM), SPRINT aims to combine the runway independence of a rotorcraft with the high-subsonic speed and performance of a jet airplane with cruise speeds of up to 400 to 450 knots (740 to 833 km/h, 460 to 518 mph).
Based on Bell's Valor-280, the X-plane ups the speed and performance by using nacelles with rotors that can be feathered and stopped before folding away as the aircraft transitions from propeller horizontal flight to jet propulsion. This gets rid of the drag produced by the rotors as they become redundant and allows for much higher speeds and stability.
