Nov 7, 2008

Flying Saucers Come Home

Forget UFOs. The first circular aircraft could soon hit the market right here on Earth. They won’t take you to space, but they might just be worth the long—very long—wait

 Fly Away: The first commercial flying-saucer line, the M200 series from Moller International, could go on sale next year.  John B. Carnett
 It’s designed to seat two, take off and land vertically, fly 10 feet above the ground, and reach 75 miles an hour. It’s about the size of a car, but it’s round instead of boxy. Yup, it’s a flying saucer. Next year, California-based Moller International hopes to introduce the M200G personal recreation craft, the first of what the company expects to be a full line of “volanters”—vertical-takeoff-and-landing aircraft. The design is 300 years in the making.

When the Wright brothers made the first powered flight in 1903, they inaugurated basic principles that survive to this day, including thin wings for lift and a vertically mounted propeller to provide forward thrust. But two centuries earlier, Swedish inventor Emanuel Swedenborg had already dreamed up a flying-saucer-shaped aircraft. Countless designers around the world have since envisioned round planes.
Because of their shape, circular aircraft can theoretically move anywhere—up, down, and side to side—without needing to point in that direction. This provides the potential for highly attractive vertical-takeoff-and-landing (VTOL) or short-takeoff-and-landing (STOL) capabilities, the latter of which permits the use of a far shorter runway than is needed by conventional craft of the same size. Armed forces worldwide are especially interested in VTOL and STOL airplanes because they can lift off from cramped aircraft-carrier decks or almost any flat surface in remote locations where runways are not available. Round aircraft are also advantageous in principle because they could fly faster than the other notable VTOL aircraft, helicopters, and their thin shapes are potentially far less detectable by radar, making them ideal for covert reconnaissance missions. Not to mention, the concept is just plain cool.

With all these advantages, circular aircraft should be commonplace by now. So where are all the flying saucers? Despite the benefits, the technology has long been hampered by major drawbacks. The biggest challenge is that round airplanes are highly unstable because they don’t employ the conventional aerodynamic systems—specifically, lift-generating wings and both vertical and horizontal stabilizers—that usually keep aircraft airborne. “If a plane is moving through the air at a high enough speed, aerodynamic forces can be used to stabilize it,” says Paul Moller, the president of Moller International. But VTOL craft, which must become airborne with zero forward momentum, need another way to generate lift and achieve stability.

To overcome this obstacle, Moller’s M200G uses its propulsion system to stabilize itself. The craft moves using eight small ducted fans, each powered by its own Wankel-style rotary engine, that lift the M200G into the air and push it forward, backward and sideways. Varying the thrust from the fans also provides stability—for example, a little extra thrust from the right-side engines prevents that side of the craft from dipping. Using multiple inertial sensors and accelerometers, an aircraft-stability computer constantly monitors the altitude of the craft and sends commands to the engines to adjust thrust in each fan up to 400 times per second, maintaining stability. The aircraft is constructed of ultralight materials such as aluminum and fiberglass, which increase the vehicle’s strength and maximize the engines’ power.

With a starting price of $90,000, the M200G will initially be a toy for the rich. It will be limited to flying below 10 feet, eliminating the need for Federal Aviation Administration certification of each pilot. Eventually, the company hopes to offer low-cost aircraft. “Artificial stability systems will get better and cost less in the future,” Moller says, “allowing us all to be able to afford strange and wonderful new flying machines that defy conventional aerodynamics.” Flying saucers, it turns out, may be just the beginning.