https://www.defensenews.com/air/2024/05 ... f-x-plane/
(...)
The Defense Advanced Research Projects Agency wants its SPRINT vertical takeoff aircraft, dubbed X-plane, to be able to fly at speeds between 400 and 450 knots, far faster than the V-22 Osprey’s maximum speed of 270 knots. SPRINT also should be able to hover in a stable manner, transition from hovering to forward flight, and feature a distributed energy system that effectively powers all the propulsion technology during that transition, a DARPA official told Defense News in December 2023. DARPA is leaving it up to companies to decide whether their aircraft should be crewed, uncrewed or able to fly autonomously.
Four companies — Boeing subsidiary Aurora, Bell Textron, Northrop Grumman and Piasecki Aircraft Corp. — received six-month contracts from DARPA in November 2023 to start their conceptual designs. So far, Aurora is the only company to receive another contract ($25 millions) to move forward on the SPRINT program, but more could be on the way. DARPA said in December that it plans to cut at least one of the four companies from contention after the conceptual design phase.
(...)
Aurora’s blended-wing aircraft design would use three embedded lift fans to fly vertically and then shift to a set of embedded engines to fly forward. This design would cut down on drag and allow it to fly at high speed, the company said, making the concept well suited for air mobility and special operations missions. The company released new concept art Monday that shows its aircraft would be uncrewed and have a composite exterior. The firm said the aircraft can reach a cruise speed of 450 knots. Aurora said it could add more lift fans to its fan-in-wing design — if the military’s requirements for such an aircraft chang — and create a crewed aircraft using the same fan technology. Aurora said its SPRINT team expects to finish the preliminary design review in about one year, with a goal of its first flight in three years.
Bell is taking a different approach than Aurora on SPRINT, having released concept art in November 2023 showing a tiltrotor design not far off from the traditional Osprey aircraft.
(...)