Giving the Autogyro a whirl

CHICAGO — High-school science teachers in 1966 wouldn't let David Groen build an autogyro — a helicopter-like craft powered by a small engine and lifted with a single rotor — from a kit because of safety issues.

Who could blame them? The autogyro went out of style with the zeppelin. It looked like something out of science fiction and could pitch over in a gust of wind. But Groen never gave up on his dream and today, four decades later, he seems on the verge of bringing back the curious contraption.

Groen, who was a commercial helicopter pilot for 15 years after serving in Vietnam, says the urge to build a better aircraft is in his blood. "I was born on an airport in disabled-veteran housing in Salt Lake City. I grew up under air-traffic patterns, listening to airplane noises day and night."

Groen and his brother Jay formed Groen Brothers Aviation Inc. in 1986 in Salt Lake City, making gyroplanes — the modern name for the aircraft — for kit builders. Groen Brothers has filed patents to perfect small craft for 20 years, but it is only in the past few years — in the wake of the terrorist attacks of September 2001 and amid a surge in fuel prices — that it is garnering attention.

The gyrocraft's design made it vulnerable to "power pushover" — a gust of wind could force the nose of the aircraft into the ground. Or an abrupt loss of power could cause it to pitch up. Groen Brothers solved the problem by patenting "centerline thrust," putting the thrustline of the engine below the drag center of the rest of the plane.

After a successful test run at the 2002 Olympics in Salt Lake City, Groen Brothers is in talks with law-enforcement agencies and the Defense Department on using gyroplanes to ensure national security.

The main drawback to a gyroplane compared with its cousin the helicopter is that, although they can fly very slowly, gyroplanes can't hover. However, compared with helicopters, gyroplanes are cheap and easy to fly. With lower fuel consumption and fewer mechanical parts, Groen Brothers's SparrowHawk, a two-seater model developed for law enforcement, costs just $25 an hour to operate, less than half of the cost for a small helicopter. The base price of a SparrowHawk patrol vehicle, equipped with communications equipment and a flight-data recorder, is $65,000, compared with about $500,000 for a helicopter suitable for surveillance work.