Centuries after Leonardo Da Vinci sketched designs of a giant bat-shaped craft that used a pilot's arms and legs to power the wings, 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.
The Snowbird sustained both altitude and airspeed for 19.3 seconds, in an 2 August test flight near Toronto that was witnessed by an official of the Federation Aeronautique Internationale, the University of Toronto announced.
A video of the flight was shown on news programs.
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," says chief structural engineer Cameron Robertson. "We believe we are the first, because we know what it took to do it."
The aircraft weighs just 42 kilograms, but has a wing span of 32 metres, which is comparable to that of a Boeing 737 airliner.
A tow car helped The Snowbird lift clear off 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 needed to help with take-off, 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 metres at an average speed of 25.6 kilometres per hour, although the day ended with a broken drive line that has since grounded the aircraft.
The Wright brothers' first powered flight in 1903 lasted 12 seconds and covered 37 metres.
Centuries of dreaming
Da Vinci sketched designs of a human-powered flying machine in the late 1400s.
But 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, says Robertson.
The Snowbird is not the first human-powered aircraft to successfully fly.
The Gossamer Condor used a pedal-powered propeller in 1977 to cover a 1.6-kilometre figure-eight course in 7.5 minutes. One later flew across the English Channel.
There have been earlier attempts at building an ornithopter that made it off the ground, although those aircraft are seen as having just glided after getting airborne.
Robertson says the team will likely turn their attention to building a piloted engine-powered ornithopter.
Past flights of engine-power ornithopters have involved remote-controled aircraft.