How to make PVC wind turbine blades
Cutting PVC Blades - makes 8 blades (or 2+ blade sets), 2 ft long, and a thin waste strip.
Place the 8 " diameter, 24" Length of PVC pipe and square tubing (or other straight edge) side by side on a flat surface. Push the pipe tight against the tubing and mark the line where they touch. This is Line A.
Make a mark near each end of Line A, 23" apart.
Tape 3 sheets of A4 paper together, so that they form a long, completely straight piece of paper. Wrap this around the pipe, about a half inch from the end. Make sure the short side of the paper is straight along Line A and the paper is straight against itself where it overlaps. Mark a line along the edge of the paper and call this line B. Repeat at the other end of the tube, calling this line C.
Start where Line A intersects Line B. Going left around Line B, make a mark at every 145 mm. The last section should be about 115 mm.
Start where Line A intersects Line C. Going right around Line C, make a mark at every 145 mm. The last section should be about 115 mm.
Mark each line using a straight edge. You will have 4 sections of equal size. Later, we'll cut these sections into 2 blades each.
Cut along these lines, using the jigsaw, so that you have 4 strips of 145 mm and one strip about 115 mm.
Take each strip and place them with the inside of the pipe facing down.
Make a mark at one end of each strip 115 mm from the left edge.
Make a mark at the other end of each strip 30 mm from the left edge.
Mark and cut these lines, using the jigsaw. NOTE: you may want to cut just two of these strips to start. This gives you 4 blades and you are only using 3. These blades will turn a generator motor in a CCW direction. If your motor turns clockwise, you can follow the same steps, but measure the 115 cm mark and 20 mm mark, from the RIGHT edge rather than the left edge. (step 9 & 10)
Place each blade with the inside of the pipe facing down.
Make a mark along the angled line of the blade, 3" from the wide end.
Make another mark on the wide end of the blade, 1" from the straight edge.
Connect these two marks and cut along the line. This prevents the blades interfering with the others' wind.
Sanding the Blades
You should sand the blades to achieve the desired airfoil. This will increase the efficiency of the blades, as well as making them quieter.
The angled (leading) edge wants to be rounded, while the straight (tailing) edge wants to be pointed.
Any sharp corners should be slightly rounded to cut down on noise.