DARPA selects Bell Helicopters to build SPRINT high-speed VTOL craft

Bell Helicopters' SPRINT design. Although SPRINT is designed to lift a 5,000 lb payload, the design could be scaled up to carry heavier cargo or personnel. (Bell Helicopters)

The US Defense Advanced Research Projects Agency (DARPA) has selected Bell Helicopters to build the Speed and Runway Independent Technologies (SPRINT) unmanned aerial vehicle (UAV), a craft capable of vertical take-off and landing (VTOL) and cruising at jet-like speed, according to a 9 July statement by the company.

Bell Helicopters submitted a tiltrotor design, capable of angling wingtip-mounted rotors from vertical to horizontal for forward flight, then folding the rotors to allow a rear-mounted jet engine to propel the UAV to 400 kt or higher.

“In preparation for X-plane development, Bell has completed significant risk reduction activities including demonstrating folding rotor, integrated propulsion, and flight control technologies at Holloman Air Force Base as well as wind tunnel testing at the National Institute for Aviation Research at Wichita State University,” Bell Helicopters said in a statement.

The company declined to answer additional questions about the craft.

SPRINT is a joint DARPA/US Special Operations Command (SOCOM) project intended to demonstrate that craft can lift off and land vertically from an unprepared surface, cruise at 400–450 kt, and reach an altitude of 30,000 ft with a 5,000 lb (2,268 kg) payload.

DARPA selected four companies for Phase 1A of the programme in November 2023 – Aurora Flight Sciences, Bell Helicopters, Northrop Grumman, and Piasecki Aircraft Corporation. In May 2024, the agency downselected to Aurora Flight Sciences and Bell Helicopters for Phase 1B, intended to advance the companies' designs from Conceptual Design Review through Preliminary Design Review (PDR). Aurora Flight Sciences' design was a blended wing-body with embedded fans-in-wing, capable of redirecting forward thrust vertically.