DARPA's SPRINT aims to develop next-gen runway-less VTOLs

DARPA has announced an initiative called SPRINT (SPeed and Runway INdependent Technologies), inviting designers to develop aircraft that can fly fast and take off and land without the need for runways. The agency aims to have a demonstration flight within 42 months. SPRINT seeks to create an aircraft capable of cruising at 400 knots (460 mph), faster than Black Hawk helicopters but slower than an F-16 fighter jet. The aircraft should also be able to hover in austere environments like fields or deserts.

“The objective of the SPRINT program is to design, build, certify, and fly an X-plane to demonstrate enabling technologies and integrated concepts necessary for a transformational combination of aircraft speed and runway independence for the next generation of air mobility platforms,” explained DARPA’s in an official press release.

The program aims to show how to use the right technologies and integrated ideas to make next-generation air mobility platforms faster and less dependent on runways. Traditional runways have limited space and visibility, so aircraft stationed in one place are more likely to be attacked by surprise. This problem is particularly relevant to potential conflicts in the Pacific region.

The shape of the new vehicle is undetermined, according to Patrick Tucker of Defense One. “It could be a new helicopter or perhaps a vertical-takeoff-and-landing aircraft that might fly even faster.”

Tucker also noted that the director of DARPA “deliberately avoided calling the program a vertical-lift effort, and an accompanying slide displayed two artists' concepts that were decidedly unhelicopter-like.”

The final design of the SPRINT aircraft is yet to be determined, with possibilities including a new form of a helicopter or a vertical-takeoff-and-landing (VTOL) aircraft. Current helicopter designs offer runway independence but have speed and efficiency limitations. The military has been trying to solve this problem for decades. They have devised two reasonable solutions: tiltrotor planes, like the V-22 Osprey and V-280 Valor, and aircraft with ducted exhaust, like the Harrier Jump Jet and F-35B stealth fighter.

But DARPA's sketches of the SPRINT aircraft don't show that it will use traditional VTOL methods. One concept features a plane with jet-like ducts and folded blades on nacelles, with wings positioned like a tiltrotor. Another idea looks like a flying wing with a V-shaped tail. This suggests that ducted fans or rotors could provide lift in the vertical direction, while jet intakes could move the plane forward.

Creating a fast-flying plane that doesn't need a runway could increase the range of aircraft and make them more useful for different military tasks. DARPA's job is to show that a design is technically possible, which makes it easier for others to make it work in the real world.