I was very interested to learn that Aurora Flight Sciences has won the Phase 2 award of DARPA's X-Plane vertical takeoff and landing project. Here's an artist's concept of its proposal.
DARPA said in a press release:
DARPA has awarded the Phase 2 contract for VTOL X-Plane to Aurora Flight Sciences.
“Just when we thought it had all been done before, the Aurora team found room for invention—truly new elements of engineering and technology that show enormous promise for demonstration on actual flight vehicles,” said Ashish Bagai, DARPA program manager. “This is an extremely novel approach,” Bagai said of the selected design. “It will be very challenging to demonstrate, but it has the potential to move the technology needle the farthest and provide some of the greatest spinoff opportunities for other vertical flight and aviation products.”
VTOL X-Plane seeks to develop a technology demonstrator that could:
- Achieve a top sustained flight speed of 300 kt to 400 kt
- Raise aircraft hover efficiency from 60 percent to at least 75 percent
- Present a more favorable cruise lift-to-drag ratio of at least 10, up from 5-6
- Carry a useful load of at least 40 percent of the vehicle’s projected gross weight of 10,000-12,000 pounds
Aurora’s Phase 2 design for VTOL X-Plane envisions an unmanned aircraft with two large rear wings and two smaller front canards—short winglets mounted near the nose of the aircraft. A turboshaft engine—one used in V-22 Osprey tiltrotor aircraft—mounted in the fuselage would provide 3 megawatts (4,000 horsepower) of electrical power, the equivalent of an average commercial wind turbine. The engine would drive 24 ducted fans, nine integrated into each wing and three inside each canard. Both the wings and the canards would rotate to direct fan thrust as needed: rearward for forward flight, downward for hovering and at angles during transition between the two.
The design envisions an aircraft that could fly fast and far, hover when needed and accomplish diverse missions without the need for prepared landing areas. While the technology demonstrator would be unmanned, the technologies that VTOL X-Plane intends to develop could apply equally well to manned aircraft. The program has the goal of performing flight tests in the 2018 timeframe.
There's more at the link. Here's a video demonstration of the concept.
This is a fascinating proposal for several reasons. It uses ducted fans in a new way, relying on lots of small fans rather than a couple of big ones. If that works in the X-plane, the next step will be to scale it up to operational size. Furthermore, the fans are electrically powered, rather than driven by a motor. That means, if battery power packs continue to develop at their present rate, in the not too distant future such an aircraft might not need an engine on board at all. Its batteries could be charged on the ground, topped up in flight by solar panels along the wings and fuselage, and fully recharged from an external source once it reaches its destination or returns to its point of departure.
I'll be watching this project with a great deal of interest. Good luck to Aurora and its partners.