To touch the sky

Abstract:

Engineers James DeLaurier and Jeremy Harris have designed an ornithopter, the first engine-powered, flapping-wing aircraft that is able to fly. The scientists’ research has provided computer models about how birds fly.

Full Text:

Mankind was fascinated by flight long before the Icarus of Greek mythology flew with wings of feathers and wax more than 5,000 years ago. But like the daring Icarus, who defied his father and flew too close to the sun, where his waxen wings melted, efforts to imitate the flapping flight of birds have crashed in failure. When Orville Wright made his maiden flight near Kitty Hawk, N.C., on Dec. 17, 1903, it was aboard a fixedwing aircraft. And most inventors have long since given up trying to create an airplane that flaps its wings. But James DeLaurier, a professor of aerospace engineering at the University of Toronto’s Institute for Aerospace Studies, and Jeremy Harris, a principal research engineer at the Battelle Memorial Institute in Columbus, Ohio, have spent two decades trying to solve the riddle of bird flight. And this fall, they succeeded. Their 8.8-lb. remote-controlled ornithopter, powered by a one-horsepower piston engine, flapped aloft from a hill near Bond Head, north of Toronto, flew for 1 1/2 minutes and touched down into aviation history. Declared DeLaurier: “As far as we are aware, it’s the first engine-powered flapping-wing aircraft to fly.”

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The violent flapping motion of DeLaurier and Harris’s invention makes it unlikely that a larger model would ever ply the commercial air routes. But the two scientists’ research provided computer models that have helped to shed new light on how birds fly. They have already put those programs to use: they tested the flight-worthiness of a model pterodactyl that California-based Aero Vironment Inc. built. And the ornithopter has capture the immagination of aviation enthusiasts. An IMAX crew filmed the plane’s first flight, and the two scientists plan to display a larger, sleeker version of Expo 92 in Seville, Spain. Said Aero Vironment vice-president Ray Morgan: “It was an interesting and very difficult problem to solve, and says a lot about the perseverance and ingenuity of its inventors.”

The ornithopter’s successful debut, in fact, followed 20 years of tests, crashes and almost insurmountable problems. In the late 1960s, Harris said, he was convinced that most of the fundamental work behind fixed-wing and helicopter flight had been exhausted–and he decided to pursue uncharted territory. When DeLaurier went to work at the Battelle institute in 1972, Harris found someone who shared his interest, and the two began their long collaboration.

Their hobby soon took up most of their spare time and, eventually, about $6,000 of their own money. “We had a real tiger by the tail,” said DeLaurier. The men abandoned their slide rules and developed a computer program to juggle the many variables that went into the design. They tested their first models in a miniature wind tunnel in Harris’s basement. After DeLaurier went to Toronto in 1974, the men continued their research long-distance. Harris worked on a drive mechanism while DeLaurier tested various wings at a larger wind tunnel in Toronto. Then, with each design, Harris travelled to Ontario for test flights.

They faced many obstacles. “Things would break,” said DeLaurier. “Shafts would twist, belts would strip and things would go flying off here and there.” There were times when the two despaired of ever solving the problem. Declared Harris: “The amount of our lives that it soaked up got a little out of hand. When that happens, you have to make a choice: drop it and let that investment go, or hang on by your fingernails. We chose to hang on.”

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Great minds had already tried to solve the riddle. In the 15th century, Italian artist Leonardo da Vinci made elaborate drawings of a flapping flying machine. And in the late 1800s, designers built tiny ornithopters powered by rubber bands. But no one had been able to create a heavier, engine-powered model. Fixed-wing flight is easier–the wings only have to provide the lift to keep the plane aloft, while the power to drive it is supplied by propellers or jets. “If we do it bird style,” said Harris, “we have to combine the lifting and the propelling in the same motion by flapping the wings.” Harris and DeLaurier finally designed a 10-foot wing made up of three panels. On the downstroke, the middle parcel over the plane’s back moves up, causing the two outer panels to pivot down. On the upstroke, the centre panel moves down and the side panels pivot up. The countermovements of the panels proved key to keeping the plane aloft.

The ornithopter is unlikely to revolutionize aeronautical theory. But it has generated much interest. “It is humanity’s age-old dream of flapping-wing flight,” said DeLaurier. “It touches something inside of people which says, ‘Yeah, that’s what we really had in mind.'” Five millennia after the mythical Icarus fell into the sea, science has finally caught up with legend.

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