Sikorsky/lockheed ($14.4 million)
Working with Lockheed Martin’s famed Skunk Works, the Sikorsky team is offering a design whose likeness can be found only on the Wheel of Misfortune. It’s a tailsitter. The 1950s Convair XFY-1 and Lockheed XFV-1 were Navy-financed Pogos: Sitting on their tails, they pointed straight up for take off and landing. Big counter-rotating propellers on their noses did the lifting. “The poor pilot was looking over his shoulder trying to land the thing nose-up,” says Linda O’brien, Sikorsky’s program manager. But that won’t be a problem for Sikorsky’s Unmanned Rotor Blown Wing, which won’t carry a crew and will be flown by computers. “Autonomy gives a lot of flexibility in flying a vehicle like this,” O’brien says.
An artist’s rendering shows an aircraft whose 36-foot wingspan holds two stationary proprotors, each 15 feet in diameter and positioned midway between wingtip and centerline. Between the rotors, the wing sports a pod, similar to the cockpit placed between the engine nacelles on a World War II P-38 Lightning. Unlike the P-38, the Sikorsky VXP lacks pylons leading to a horizontal tail. Instead, behind each of the proprotors—or under them when the aircraft sits on its tail—is a vertical tail at right angles to the wing that extends both up and down in horizontal flight.
O’brien says a tailsitter is “the simplest way to capture VTOL and speed because there’s no morphing of the aircraft. It takes off on its hind legs, so to speak, pitches over, and transitions into forward flight. You don’t expend the weight and system complexity to morph or pivot or transform the airplane in any way.” The Unmanned
( Rotor Blown Wing is meant to stay that way, but O’brien says the companies have concepts for “tilt-wing versions of this that you could put a human in.”
Mark Alber, manager of advanced concepts at Sikorsky and chief engineer on the project, says the aircraft is called the Rotor Blown Wing because, given the size of the proprotors, “there is a very high percentage of the wing that’s being blown by the rotor wash.” This provides extra lift that enables the craft to have a smaller wing and greater speed. O’brien predicts the aircraft will fly “significantly” faster than the minimum 300 knots DARPA requires.
DARPA project manager Bagai refuses to discuss how the winner of the competition will be chosen. Nor will he venture whether the result might meet the “substantially everything a bird can do in the air” standard. In some ways, Bagai argues, Klemin’s vision was exceeded long ago. Not that many birds can hover, he notes, and none flies faster than the speed of sound. But birds far outclass manned aircraft in maneuverability and, he admits, in the way they can quickly land on a tree branch or telephone line.
As for the more practical question of how much the VTOL X-plane project will advance vertical flight, Bagai says, “Whether the types that we’re developing right now are the concepts that darken the skies or it’s a spinoff from that that darkens the skies, I think either way it’s a huge ramification.” Were he alive, Klemin would surely be pulling for the designers to prove Bagai right.