Early ground effect testing has demonstrated its fan-in-wing vertical lift system.

DARPA is running the SPRINT program jointly with the US Special Operations Command. The stated goal is "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."

Essentially, the outcome will be a proof-of-concept demonstrator for a new class of military aircraft with the ability to move troops and/or cargo much faster than helicopters, with the operational flexibility of land-anywhere VTOL – so it's not there to compete with the F-35 Lightning as a VTOL-capable fighter plane, more as a high-speed transport option.

It's currently in Phase 1B – the preliminary design stage, in which Aurora's fan-in-blended-wing design is competing against Bell's HSVTOL concept, which is more like a Bell Boeing V-22 Osprey tilt-rotor – except with big ol' jets taking over for high-speed cruise flight as the large VTOL rotors fold out of the way.

The demonstrator – should Aurora win the contract to build it – will be an uncrewed plane with a 45-ft (14 m) wingspan, capable of carrying 1,000 lb (454 kg) of payload. Its turbofan and turboshaft engines will give it a maximum speed around 450 knots (518 mph / 834 km/h).

Its VTOL system will consist of three vertical lift fans – one in each wing, and one in the forward-center of the fuselage, with aerodynamic covers for cruise flight that fold open when it's time for the lift fans to get to work.

But the full-size vision here is more than twice that size, with a wingspan of 130 ft (40 m) and a payload bay door some 40 ft (12 m) wide. This machine will use four lift fans, two in each wing, with more complex slatted covers on the tops and bottoms – presumably these might even offer some thrust vectoring capabilities for added agility, responsiveness and stability in a hover.

It's interesting to note that there don't seem to be any flaps or physical control surfaces on the full-size concept pictured here. A simple matter of lazy Friday-afternoon rendering at Aurora, or perhaps a nod to another project the company is working on for DARPA?