Wind Turbine Blades
January 13, 2010 by Build Your Own Wind Turbine
Filed under Home Wind Turbine
When making wind turbine blades you can use metal wood or fiberglass. Sometimes, turbine blades are also cut from pieces of PVC pipe. Fiberglass is very light and long lasting. It is not subject to stress fatigue like other materials. This is why it is most commonly used as blade material in the giant commercial wind turbines in production today.
Wood is easier to work with than fiberglass or metal and it is lighter than metal, so this makes it the obvious choice for home DIY turbines. Although there are one and 2 blade designs, most home wind turbines have 3 blades. Three blades will turn the rotor at a higher speed in lower winds, which is why it is considered best. Another consideration is that three blade turbines are quieter and easier to balance than their one and two blade counterparts.
All horizontal axis wind turbines share basically the same design style. Much like the wings on an airplane, wind turbine blades are airfoil shaped to create lift and help maximize efficiency. Since the blades move faster at the outer ends and slower in the middle, they usually have a twist to their shape. This twist optimizes angle of attack along the blade. To further improve aerodynamic performance, the blades are also tapered.
Regardless of the consistencies in blade design, their dimensions must be compatible with the overall machine design and location. Control over speed and torque is required to optimize aerodynamic efficiency in light winds. Once the turbine’s maximum speed for energy creation is reached, it must be slowed down.
So the turbine must be prevented from spinning faster than its maximum capacity can handle. Diameter, blade size and weight all contribute. If the blades are too big or too small for the alternator the turbine won’t work properly, if at all. The turbine will not be able to turn into the wind or furl to a slower speed when required if the tail assembly isn’t the correct size and weight and size.
As you can see, the blade specifics must be relative to the turbine’s other components. There are many do-it-yourself project guides available for building a complete home wind turbine system, but only a few include the details required to build a fully balanced and efficient system. Readers can learn more about wind turbine blade construction here.
Nick Molinar runs DIYHomePowerGrid, where he discusses home grown power generation systems including solar, wind and automotive alternatives.
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