Customers who buy our educational wind turbines sometimes call asking for advice on how to maximize turbine power output. While we have left many factors up to experimentation with blade design, wind speed is a significant element. Recall that the power in the wind is equal to 1/2 (density of the air * swept area of the rotor * velocity of the wind³). When you increase your wind speed, you increase your power dramatically. Thus, when using KidWind turbines, the fan is an important aspect of power production.

Basic criteria for fans:

1) Minimum 20" diameter: Our balsa and coroplast blade sheets are between 16"-18" per blade. If you use these materials, the maximum swept area of a KidWind turbine will be around 32"-34", not including extra space for dowels. The blade material that exceeds the diameter of the fan's swept area will create drag and reduce turbine power output. You will have to trim down your blades to accommodate the swept area of the fan. Therefore, a 20" diameter fan is our minimum recommendation for proper turbine experimentation.

 

2) Wind speed of at least 9 mph: The Lasko cyclone models and the Lasko box fan Model 3723 produce good wind velocity. We don't recommend high velocity fans. These tend to be too powerful, and may blow you and your wind turbine away. Even MW producing wind turbines can't function with too much wind. See what happens to a turbine whose fail-safe mechanisms malfunctioned under high wind conditions. >>

 

3) Use a box or floor fan: we do not recommend the use of oscillating pedestal fans. They tend to have smaller swept areas, are often too tall, and will have to be turned to a non-oscillating mode in order to get consistent wind speed. At KidWind we use box or floor fans to avoid the above problems, and because they tend to be more powerful. They can be propped vertically, or stabilized using horizontal props.

 

4) Use a fan with settings: Most fans have settings. A fan with different power settings will be good for doing experiments on the effect of wind speed on your turbine. In addition, if blade designs are different, power output ratios may be different with changing wind speeds.

 

We have a short list of fans that we use in our workshops. We recommend the Lasko brand.

 

Best

Cyclone Floor Models - Model 3520 ran 12mph on speed setting 3
Box Fan 3723

 

Ok

Box fan 3733

 

If you find a fan that has worked particularly well, let us know here.