Bell completes CDR on DARPA SPRINT X-76 program

Fort Worth-based Bell Textron Inc has successfully held the Critical Design Review (CDR) for the next-generation aircraft demonstrator, designated the X-76. This milestone allows construction to begin on the platform that is the focus of the Defense Advanced Research Projects Agency’s (DARPA) Speed and Runway Independent Technologies (SPRINT) program.

The SPRINT program’s X-76 aircraft is a proof-of-concept technology demonstrator. Its goal is to provide military aircraft with runway-independent technologies that enable a cruise speed of 400 to 450kt but allows them also to hover in austere environments and operate from unprepared surfaces. The technology is designed to be scalable to match different missions.

Artist’s impressions of the X-76 show what looks like a tilt-rotor aircraft with the wingtip-mounted engines and propeller blades folded flat to reduce drag; the aircraft is powered in wing-borne flight by an unspecified jet engine and has a butterfly tail with no fin and no tailplane. It also appears to be autonomous, though its designation doesn’t include the letter ‘Q’ which is normally applied to robotic or autonomous aircraft.

In July 2025, the company was down-selected for Phase 2 of the program, which is jointly funded by DARPA and US Special Operations Command. In Phase 1A and 1B Bell completed conceptual and preliminary design efforts for the SPRINT X-plane. Phase 2 includes detailed design, build, and ground testing culminating in flight test during Phase 3.

“For too long, the runway has been both an enabler and a tether, granting speed but creating a critical vulnerability,” said CDR Ian Higgins, US Navy, who is DARPA’s SPRINT program manager. “With SPRINT, we’re not just building an X-plane; we’re building options. We’re working to deliver the option of surprise, the option of rapid reinforcement, and the option of life-saving speed, anywhere on the globe, without needing any runway.”

Bell says it has completed significant X-76-related risk reduction activities including demonstrating folding rotor, integrated propulsion, and flight control technologies on the High Speed Test Track at Holloman Air Force Base in New Mexico, as well as wind tunnel testing at the National Institute for Aviation Research (NIAR) at Wichita State University.