Living Wisdom High School Physics:

      The wind blades are very important to the function of the wind turbine; they are carved out straight-grained cedar, and have to be very straight,  knot-free,  and light. The blades are shaped like an airplane wing. This gives the blades more lift and less wind resistance, making the tips of the blades able to spin at up to seven times the speed of the wind! Each of the blades is five feet long and there are three-per-turbine. They are off set so the total blade diameter is about eight feet.
 
   
  
   The "blade girls" used a drawknives and an orbital sander to get the perfect aerodynamic shape. Through a variety of stages, one had to very carefully measure and carve. It took about eight practice blades before we finally started to get functional blades; and each blade took about twelve hours to carve! There was an especially hard learning curve at the final stage of carving the blades. Some of the wood gets down to a millimeter thick, and you can’t let your attention wander for a second. If you do, one wrong pull with the drawknife will ruin twelve hard hours of work.


The girls also painted the blades and put aircraft leading-edge tape on them. This is so the friction of the wind won’t erode the blades as fast. The blades were then held fast together via two plywood discs and mounted onto the alternator.