Aurora reveals SPRINT fan-in-wing design progress

Aurora Flight Sciences (Bridgeport, W.Va., U.S.), a Boeing company, is designing an X-plane featuring three lift fans, a more refined composite exterior, an uncrewed cockpit and the use of fan-in-wing (FIW) technology to provide high-speed, runway-independent mobility. Newly released renderings of the vertical lift concept depict a scalable technology for airborne logistics and personnel recovery missions in locations without a prepared runway.

The design work is part of the Defense Advanced Research Projects Agency (DARPA) Speed and Runway Independent Technologies (SPRINT) program. The SPRINT program aims to design, build and fly an X-plane to demonstrate the key technologies and integrated concepts that enable a transformational combination of aircraft speed and runway independence.

Aurora and Boeing are collaborating on the development of key technologies that combine to deliver a solution to mobility challenges in contested environments and across distributed military bases. According to partners, FIW technology combines an embedded lift fan with a blended wing body design to enable vertical lift agility without sacrificing the payload capacity and aerodynamic efficiency associated with today’s fixed wing aircraft.

The team is currently designing an uncrewed demonstrator with a 45-foot wingspan and 1,000-pound payload capacity for SPRINT. The propulsion system includes off-the-shelf turbofan and turboshaft engines that would power the vehicle to a maximum of 450 knots true airspeed (KTAS).

The companies note that the demonstrated technology could be scaled to medium- and heavy-lift aircraft, creating a future family of systems. For example, Aurora envisions a manned, 130-foot wingspan aircraft with four lift fans and a 40-foot payload bay. The FIW aircraft has the potential to meet or exceed the payloads, ranges and speeds typical of fixed-wing military transport aircraft while delivering the tactical advantage of vertical takeoff and landing.

“The SPRINT program offers the opportunity to deliver capability to the warfighter,” says Mike Caimona, president and CEO of Aurora Flight Sciences. “High-speed, stealth, runway-independent transport could help keep warfighters safe and effective in contested environments.”

Earlier this year, the team completed the first of three major test events scheduled for the current phase of the SPRINT program to prove out the feasibility of the FIW technology. The ground effect test, conducted using a 4.6-foot wingspan model with three lift fans, showed that suckdown effects created by the lift fans in hover were negligible and that the landing gear is set to the appropriate height to minimize adverse pitching moments from forming during ground operations. Wind tunnel tests planned for late 2024 and early 2025 include a stability and control test using a 9-foot full wingspan aircraft model and a 5¼-foot semi-span embedded lift fan test to model aerodynamic effects.

The current phase of the program continues through May 2025 with preliminary design review scheduled for April 2025. Flight testing for the program is planned for 2027.