Dr. Red
15th Dec 2000, 12:48
Another interesting article from New Scientist Magazine:
<font face="Verdana, Arial, Helvetica" size="2">Can pedal power help a helicopter take to the skies?
In an abandoned brewery in downtown Montreal this week, the first rotor of a revolutionary human-powered helicopter will be slotted into place. The move marks a major milestone in an ambitious attempt to win the US$20,000 Sikorsky Prize for human-powered helicopter flight.
The helicopter's unique design uses a pair of rotors above and below the pilot, which counterrotate to provide undreamed stability. To win the prize, it will have to hover above a 10-metre square for 60 seconds, reaching an altitude of 3 metres. It's a tough task. Out of 17 attempts since the prize was first offered in 1980, 15 failed to get off the ground and the two that did fly failed to stay aloft for more than 25 seconds.
But the multidisciplinary team of 15 graduate engineers from the École de Technologie Supérieure (ÉTS) in Montreal has high hopes. Its design, called Hélios, places a recumbent pilot between a pair of rotors 35 metres in diameter (see Diagram) which turn in opposite directions to give the craft stability. The blades taper from 1.25 metres wide to just 10 centimetres at the tips.
"Low weight is crucial," says Simon Joncas, the project leader. The finished carbon-fibre composite helicopter will weigh 73 kilograms, and the pedalling pilot another 70 kilograms. He will have to deliver 750 watts to make the huge rotors turn at seven revolutions per minute.
"We have tested many cyclists but only one performs as we need," said Joncas. "François Maisonneuve has trained for four years to pedal at maximum power for just two minutes." Maisonneuve previously piloted the ÉTS human-powered submarine, the Omer 3, to a world-beating 6.55 knots (3.37 metres per second) in a pool near Washington DC in June 1997.
Hélios has also borrowed the sub's highly efficient drive system, which can transfer 90 per cent of the pedaller's energy to the rotors. Instead of an endless bicycle-style chain, which would have high frictional losses, it uses a steel cable wound around a large wheel 14 times. It takes two minutes for the pilot to pedal to the end of the cable.
In flight, a computer will vary the pitch of the rotors, and motors will move masses to compensate for the movements made by the pilot as he shifts in his seat.
The coordinator of the Sikorsky Prize, Bob Huston, admires the novel Montreal design but doubts it will succeed. "I like their odds but I suspect they will fail with this configuration," he says. The attempt on the prize will take place in Montreal's Olympic Stadium next summer.
http://www.newscientist.com/ns_images/2269/226912F2.JPG </font>
Maybe one day we'll all have human-powered aircraft....
"Ladies and Gentlemen, we need a little more power, so pedal faster please"
<font face="Verdana, Arial, Helvetica" size="2">Can pedal power help a helicopter take to the skies?
In an abandoned brewery in downtown Montreal this week, the first rotor of a revolutionary human-powered helicopter will be slotted into place. The move marks a major milestone in an ambitious attempt to win the US$20,000 Sikorsky Prize for human-powered helicopter flight.
The helicopter's unique design uses a pair of rotors above and below the pilot, which counterrotate to provide undreamed stability. To win the prize, it will have to hover above a 10-metre square for 60 seconds, reaching an altitude of 3 metres. It's a tough task. Out of 17 attempts since the prize was first offered in 1980, 15 failed to get off the ground and the two that did fly failed to stay aloft for more than 25 seconds.
But the multidisciplinary team of 15 graduate engineers from the École de Technologie Supérieure (ÉTS) in Montreal has high hopes. Its design, called Hélios, places a recumbent pilot between a pair of rotors 35 metres in diameter (see Diagram) which turn in opposite directions to give the craft stability. The blades taper from 1.25 metres wide to just 10 centimetres at the tips.
"Low weight is crucial," says Simon Joncas, the project leader. The finished carbon-fibre composite helicopter will weigh 73 kilograms, and the pedalling pilot another 70 kilograms. He will have to deliver 750 watts to make the huge rotors turn at seven revolutions per minute.
"We have tested many cyclists but only one performs as we need," said Joncas. "François Maisonneuve has trained for four years to pedal at maximum power for just two minutes." Maisonneuve previously piloted the ÉTS human-powered submarine, the Omer 3, to a world-beating 6.55 knots (3.37 metres per second) in a pool near Washington DC in June 1997.
Hélios has also borrowed the sub's highly efficient drive system, which can transfer 90 per cent of the pedaller's energy to the rotors. Instead of an endless bicycle-style chain, which would have high frictional losses, it uses a steel cable wound around a large wheel 14 times. It takes two minutes for the pilot to pedal to the end of the cable.
In flight, a computer will vary the pitch of the rotors, and motors will move masses to compensate for the movements made by the pilot as he shifts in his seat.
The coordinator of the Sikorsky Prize, Bob Huston, admires the novel Montreal design but doubts it will succeed. "I like their odds but I suspect they will fail with this configuration," he says. The attempt on the prize will take place in Montreal's Olympic Stadium next summer.
http://www.newscientist.com/ns_images/2269/226912F2.JPG </font>
Maybe one day we'll all have human-powered aircraft....
"Ladies and Gentlemen, we need a little more power, so pedal faster please"