Un-Piloted Hybrid Plane: Potential Escort for V-22?

• Author: Erwin, Sandra I.
• Position: Brief Article

The U.S. Marine Corps is showing interest in a new type of hybrid vertical-takeoff and landing rotorcraft, called the canard-rotor wing. The technology--which allows the rotorcraft to shift to fixed-wing flight in midair--is in development by the Defense Advanced Research Projects Agency and the Boeing Co.

The Marine Corps is "looking at the requirement" for such a system, said George Muellner, president of Boeing Phantom Works, in St. Louis. The most likely application for the canard-rotor wing, he said during a briefing to reporters, is to "support V-22 operations."

The V-22 Osprey--a hybrid aircraft that flies like a fixed-wing turboprop and takes off and lands vertically--is the Corps' choice to replace its aging troop-transport and rescue helicopters. The Marine Corps had planned on buying nearly 400 Ospreys. That number could change, however, since the V-22 program is being restructured and will be slowed down, as a result of two accidents last year that killed 23 Marines.

If the Osprey became operational one day, the canard-rotor wing could be a suitable escort aircraft, according to Muellner. "It can operate out of the same areas, but has much higher speed [up to 400 knots]. It could be a fighter escort for the V-22."

Phantom Works currently is testing a 1,400-pound unmanned version of the aircraft. The Defense Advanced Research Projects Agency (DARPA) wants to have the option of possibly developing both piloted and un-piloted versions.

"It has all the benefits of the rotary wing and the benefits of the fixed-wing aircraft," Muellner said. "It takes off as a rotary wing, once airborne, gains speed, the upper wing turns fixed, and turns into a fixed-wing aircraft."

The canard-rotor wing vehicle has been named the "Dragonfly." The first prototype will be 18 feet long, about 6 feet tail, with a 12-foot rotor diameter.

As described by Muellner, the Dragonfly combines the hover efficiency and low-speed flight characteristics of a helicopter with the subsonic cruise speed of a fixed-wing aircraft. In both rotary-wing and fixed-wing flight modes, the aircraft is powered by a conventional turbofan engine, using diverter valves that direct the thrust to the rotor blade tips, or aft to the jet nozzle. The Dragonfly has a canard, instead of a conventional tail. The rotor is not driven by a transmission box connected to an engine, but rather by gas extracted from the main jet engine, Muellner explained.

Asked whether the Dragonfly would have...