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.
The concept of gyrodyne aircraft goes back to the early 20th century, predating the helicopter. In 1919, a Spanish inventor came up with the idea for aircraft that get lift from a single rotor. A propeller powered by a small engine at the back of the plane provides thrust. Through the 1930s, gyrodynes were used commercially to ferry passengers and mail in a number of cities, including New York, then fell out of fashion as the helicopter, featuring two rotors and a bigger engine, gained prominence.
According to Federal Aviation Administration rules, hobbyists can fly gyrocraft built from kits without a pilot's license, opening the market to many amateur fliers.
Groen Brothers plans to get FAA certification for a four-seat plane for commercial use, but that has required a significant investment for testing and upgrading equipment. The company went public in 1990 to finance its operations. In 2004, Groen Brothers reported a loss of $3.2 million, or 3 cents a share, on revenue of $194,000.
Investor interest dried up with the tech bust, followed by the collapse of the commercial-aviation industry after the terrorist attacks in 2001. FAA certification for the Groen Brothers' four-seat Hawk 4 is about three years away, although certification isn't required for craft used by government agencies.
Groen Brothers has some competition in the gyroplane business from small companies that make kits, but industry researchers say no other companies are close to Groen Brothers in cracking the commercial and government markets.
In its first serious test, Groen Brothers's 24-foot-long Hawk 4 successfully kept surveillance at the 2002 Olympic Winter Games. In one incident, infrared equipment on the Hawk detected an intruder on the grounds, Groen said. Alerted by the pilots, federal agents moved in to apprehend an armed suspect, without alarming athletes or the public.
A number of police departments have contacted Groen Brothers about using its SparrowHawk two-seat plane for surveillance. Dennis Munoz, a motorcycle officer in Atlantic City, N.J., has been a strong advocate of gyroplanes for several years. As with most smaller police departments, Atlantic City can't afford to buy a helicopter, he said. The Atlantic City police have some unique responsibilities, including protecting casinos from terrorists. The Department of Homeland Security has recommended that the gyros could be used to assist police.
A dozen local law-enforcement agencies are in talks about buying SparrowHawks, according to Groen Brothers spokesman Hank Parry.
The 12-foot-long SparrowHawk — which in basic kit form costs $32,000 — makes a short takeoff of about 400 feet, powered by a 160 horsepower Subaru engine using premium unleaded fuel. The craft can fly straight up or down to a maximum height of 10,000 feet. It cruises up to 115 mph. Should the engine fail, the aircraft can float to the ground under the wind-powered rotor.
Groen Brothers isn't limited to developing small craft. In July, it joined a team led by the Georgia Institute of Technology to develop a concept design for competition to make the "joint heavy lift vertical takeoff and landing aircraft" for the U.S. Army.
Groen Brothers's test design adds a five-blade rotor to an existing fixed-wing Lockheed C-130 transport plane. As a result, the ungainly looking 97-foot-long craft, which carries as much as 18 tons of cargo, can take off and land vertically to deliver heavy equipment in areas where there are no runways.
Daniel Schrage, professor at the school of aerospace engineering at Georgia Institute of Technology, heads research in rotorcraft and has helped design a number of military aircraft. He said the gyro beats the helicopter when it comes to heavy lifting because engines in very large helicopters become too heavy to be practical. For other tasks, smaller gyroplanes have the potential to be safer and faster than helicopters, he said.