A New VTOL UCAV Concept

I present to you the Aurora Flight Sciences Excalibur VTOL UCAV, a 40% proof of concept version, which seems to be almost as much prop as wing, paid for by DARPA.

The twist in this design is that the lift fans are driven by electric motors:

For VTOL mode, the Excalibur’s turbine engine tilts vertically and provides about 70% of the thrust, says program manager Heather Brendle. Battery-powered lift fans in the nose and wing tips provide pitch and roll control by differential rotational speed, and yaw control via vanes that deflect fan thrust. For cruise, the engine tilts horizontally, the tip fans retract into the wing, a sliding door covers the nose fan and the aircraft rolls onto its back.

The Excalibur is designed as a close-air-support UCAV. The notional 21-ft.-span full-size vehicle is designed around a 500-lb. weapons capacity—enough to carry four Hellfire missiles. This aircraft would have a VTOL takeoff weight of 4,000 lb. and useful load of 1,000 lb., increasing to 4,800 lb. and 1,900 lb., respectively, with short takeoff and vertical landing. Maximum speed would be 300 kt. at sea level, increasing to 460 kt. at 30,000 ft.; loiter speed would be 90 kt.

Aurora’s subscale, 10-ft.-span, proof-of-principle (POP) aircraft weighs in at 720 lb., with a 100-lb. useful load and 280-kt. sea-level speed. The engine is a Williams F415 turbofan from the Tactical Tomahawk cruise missile. Each common lift-fan unit is powered by four lithium polymer batteries packaged with the electric motor. The motor’s fast response allows use of a fixed-pitch fan, says Brendle.

Someone seriously thinking outside of the box here.