More Power: How to Improve Your Blades
The Kidwind model wind turbine we’ll use for the Wind Turbine Challenge is designed to perform various blade design experiments quite quickly. Efficient blades are a key part of making power from a wind turbine. Sloppy, poorly made blades produce little energy. It takes time and thought to make good blades.
One thing you must always think about when making turbine blades is, “Are my blades creating DRAG?”. Your blades are probably catching the wind and helping to spin the hub and motor drive shaft, but if they are producing too much DRAG your whole system will slow down. In most cases, low RPM (revolutions per minute) means less power output. The faster your blades turn, the more power you make!
Some tips on improving blades:
• SHORTEN THE BLADES – Students often make very big, long blades thinking bigger is better.
• CHANGE THE PITCH - Often students will set the angle of the blades to around 45° the first time they try to use the turbine. Try making the blades more
perpendicular towards wind direction.
• USE FEWER BLADES - To reduce drag try using 2, 3 or 4 blades.
• USE LIGHTER MATERIAL - To reduce the weight of the blades use less material or lighter material.
• SMOOTH SURFACES - The smoother your blade surface the less drag it will produce. A blade with lots of tape and rough edges will have more drag.
• BLADE SHAPE - Are the tips of your blade thin and narrow or wide and heavy? The tips travel much faster than the root near the hub. If you have lots of blade
area near the tips you will add more drag.
These are a just few ideas to help you improve your turbine blades. For more information, visit www.Kidwind.org and look for the Blade Design Lesson under the curricular materials. There are lots of helpful links and ideas there to help you make the best blades.