Wind-powered cars sail close to the breeze

By John Maguire
Reporter, BBC News

media captionJohn Maguire takes a look at Team Bristol's wind-powered car

On a deserted runway near the Wiltshire, Berkshire border a car emerges from an aircraft hangar.

It may look like a go-kart with huge Mickey Mouse ears made from giant desk fans, but its designers say this vehicle is highly innovative.

For the past year, a team of engineering students from the University of Bristol has designed, built and tested the wind-powered car.

When you see the vehicle in action you have to pinch yourself. As the wind blows, the double turbines begin to spin, the wheels turn and the car moves.

Progress is slow, steady, but above all surprising. And that's because the vehicle travels not with the wind, but against it. It's may appear counter-intuitive, but it works.

For propulsion, it needs a good stiff breeze, preferably well above 10mph (18km/h). The wind blows over the turbine blades and just like the familiar wind farms, they start to turn.

The higher the speed, the faster the blades spin. As they do so, through a system of cogs and gears and a drive shaft attached to the wheels, the car moves forward.

"We're not pretending we'll all be driving around in wind powered cars in the future", says Doctor David Drury, the academic in charge of the project.

"But it gives the students a brilliant opportunity to get their hands on and to put their theories to the test."

Head turner

To put the car through its paces the team took it out to the annual Aeolus Wind Turbine Race, held at an airfield in Western Denmark.

The event attracts teams of students from across Northern Europe.

image captionThe teams compete over a 500m course

The favourites from the University of Amsterdam won in 2009 and had decided to re-enter their winning design alongside a brand new car.

Their arch rivals from Utrecht arrived with a spectacular looking car and even more impressive team uniforms that included individually named jump-suits.

The team from Stuttgart had also tasted victory before. Their bright red car boasted sleek aerodynamic lines and showed early promise.

But Bristol's car, with its double turbines and electric transmission, was turning heads.

"We've thrown the vehicle together, literally, in a handful of months," James Baker, one of the team, said.

"The other teams, looking at their vehicles, have spent an awful lot more time than we have."

Record beater

The race rules dictate that the cars including the blades must be no wider than 2m (7ft) with a maximum height of 3.5m.

image captionThe car used parts designed for an electric bicycle

"No one said anything about the number of turbines though," said Mr Baker.

Using an electrical controller the driver can yaw the blades until they catch the wind.

During the course of the three-day event, the best teams set new records, well above half of wind speed. It was impressive to see the wind blowing hard in one direction and the cars travelling the opposite way.

And the Bristol team completed the 500m course in a modest 29 minutes and 46 seconds.

The overall winners, Amsterdam, made it across the line in a fraction of that time.

But for Dr David Drury the competition was about more than just crossing the finishing line.

"We've gained valuable experience," he beams, "and ideas about how we can crush the competition next year."

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