Ornithopter achieves Da Vinci's dream?
By Allan Dowd VANCOUVER | Sat Sep 25, 2010 11:28am EDT
VANCOUVER (Reuters) - Leonardo Da Vinci would be proud: the Snowbird has flown. Centuries after the Renaissance inventor sketched a human-powered flying machine, Canadian engineering students say they have flown an engineless aircraft that stays aloft by flapping its wings like a bird. International aviation officials are expected to certify next month that the Snowbird has made the world's first successful, sustained flight of a human-powered ornithopter, according to the University of Toronto.
The Snowbird sustained both altitude and airspeed for 19.3 seconds, in an August 2 test flight near Toronto that was witnessed by an official of the Federation Aeronautique Internationale, the university announced. A video of the flight was shown on news programs on Wednesday. Others have claimed to have built machines that flew like a bird, but the Canadian group says they have the telemetry data to prove their ornithopter powered itself through the air rather than just glided after being lifted aloft.
"Those past claims were never verified. We believe we are the first, because we know what it took to do it," chief structural engineer Cameron Robertson, said in an interview from Tottenham, Ontario, north of Toronto, where the Snowbird was displayed on Thursday. "This represents one of the last of the aviation firsts," said Todd Reichert, the pilot and project manager, said in a statement. The aircraft weighs just 94 pounds, but has a wing span of 105 feet, which is comparable to that of a Boeing 737 airliner.
A tow car helped the Snowbird lift clear of the ground, but then the pilot took over, using his feet to pump a bar that flaps the wings -- giving it the look of a somewhat drunken bird, according videos of the August event. The car was need to help with takeoff, because the aircraft had to be so lightweight it could not carry the equipment needed to get itself off the ground.
The ornithopter's 19.3-second qualifying flight covered a distance of 145 meters (475 feet) at an average speed of 25.6 km/h (16 mph), although the day ended with a broken drive line that has since grounded the aircraft, according to project officials. The Wright brothers' first powered flight in 1903 lasted 12 seconds and covered 37 meters (120 feet).
CENTURIES OF DREAMING
Leonardo Da Vinci sketched designs in the late 1400s of a giant bat-shaped craft that used a pilot's arms and legs to power the wings. He is not believed to have built one, and engineers now say it would not have worked if he had. The Canadian engineers had to design a flapping wing with enough lift and thrust to overcome the aircraft's weight. The computer power to calculate the design and materials needed to build the aircraft were not available before, Robertson said.
