The US Defense Advanced Research Projects Agency (DARPA) has completed the first phase of flight testing of the vertical take-off and landing (VTOL) X-Plane.

The agency started testing a sub-scale version of the aircraft, which has been developed and fabricated by Aurora Flight Sciences, in March last year.

The initial testing involved six flights, during which the aircraft demonstrated auto take-off, sustained hover, directional and translational control (including lateral and rearward flight), waypoint navigation, and auto landing capabilities.

The aircraft wing and canard tilt mechanisms, tilt schedules, and wing-borne flight controls were also enabled for testing, DARPA stated.

DARPA programme manager Ashish Bagai said: “The VTOL demonstrator was designed specifically to test the aerodynamic design of the aircraft, validate flight dynamics, and develop the flight and mission-systems controls for application to the full-scale vehicle.

“The aircraft exhibited exceptional flight characteristics, with no loss in altitude even as it transitioned from vertical to horizontal flight. It also demonstrated aerodynamic effectiveness of the distributed propulsive system.”

The aircraft is equipped with 24 electric ducted fans, of which 18 are distributed within the main wings and six in the canard surfaces.

"The aircraft exhibited exceptional flight characteristics, with no loss in altitude even as it transitioned from vertical to horizontal flight."

The wings and canards of the aircraft are tilting upwards for vertical flight and rotating to a horizontal position for wing-borne flight.

DARPA now plans to develop a full-scale version of the plane, XV-24A, which will feature a triple-redundant flight control system instead of a single system.

The full-scale aircraft's fan units will be powered by a hybrid turboshaft engine, driving electric generators.

With flight speeds of more than 300k, the full-scale XV-24A, with full hover and vertical flight capabilities, will weigh 12,000lb.

Image: The initial testing of VTOL X-Plane involved six flights. Photo: courtesy of Defense Advanced Research Projects Agency.