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Environmental  The Windcar Project
Building and optimising the speed and efficiency of a vehicle which is driven solely by wind energy and drives straight against the wind is a fascinating thoeretical and experimental challenge for students.
A simple formula for the efficiency of such windcars can be developed using the basic principles of mechanics.
The optimum angle of the rotor blade's orientation is an interesting field of applied aerodynamics and can be calculated using a simple differential calculation. The conditions which are optimum for windcars differ from those for wind power plants, which leads to interesting comparisons and knowledge of this sustainable energy technology. It turns out that wind power plants do not have such a bad efficiency as is sometimes claimed with repect to the Betz' limit, which lies around 60% - this "limit" is irrelevant for wind power.
However, the proof of this daring theory can only be the experiment. My students have built better and better windcars: their efficiency has increased from 6% to about 25% - according to tests conducted in the largest Austrian climate wind tunnel. Now we are trying to increase it beyond 50\%.
The accurate measurement of the propeller efficiency (defined for the purpose of windcars) is still a challenge. We believe that we have measured values between 50% and 60% but as mentioned before: the proof will be the velocity that the car can reach in a race against the wind.
Contact details
Last update: 17 July 2007
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