Here you will find detailed instructions on how to build a 4 foot wind turbine. A

turbine of this size, should generate about 100 watts in a strong wind. This will never be enough to take you off the grid, but the project is quite simple and you will learn lots. Once I had gathered the parts I needed, I had the turbine finished  in a day. I have tried to include the basic instructions and some pictures. If you need more detailed pictures, please take a quick look here:

http://www.greenterrafirma.com/DIY_Wind_Turbine.html

Generator/Treadmill Motor

A 260 VDC, 5 A continuous duty Treadmill Motor with a 6 inch threaded hub is best suited for a small wind turbine. These motors are available on eBay. You can get about 7 amps in a 30 mph wind. In other words, it is a simple, cheap little machine to get you started. You may use any other simple permanent magnet DC motor that returns at least 1 V for every 25 rpm and can handle upwards of 10 amps.

Tail & Mount :Option #1

• 36" of 1" Square Tubing
• 2" Floor Flange
• 2" X 4" Nipple
• 3 X 3/4" Self-tapping Screws

Tail & Mount :Option #2

• 36" of 2" "L" Tubing
• A rotating dolly wheel with a hole in the centre (see picture) . This is also called a hollow kingpin caster. In Canada, you can get it at Rona hardware stores.
• 2 X 3" bolts with locking washers and nuts

Tail

• 1 sqft (approx) lightweight material (metal) - used roller paint tray will work
• 2 X ¾" Self-tapping Screws

Blades

• 24" length of 8" PVC Pipe (if it is UV resistant, you will not need to paint it)
• 6 X ¼" X 20 Bolts
• 9 x ¼" washers
• 3 sheets A4 paper and tape (to mark the PVC to cut it)

Cutting Blades - makes 8 blades (or 2+ blade sets) and a thin waste strip.

I have a separate website with more pictures and expanded instructions on this process a bit. After you've done this once, it makes sense. These instructions could use a little help for the first time wind turbine blade maker.

Here's the link to the page: Making PVC Turbine Blades

1. Place the 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.
2. Make a mark near each end of Line A, 23" apart.
3. Tape 3 sheets of A4 paper together, so that they form a long, completely straight piece of paper. Wrap this around the section of pipe at each of the two the marks you just made, one then the other. 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 at each end. Call one LineB and the other Line C.
4. 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.  
5. 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.  
6. Mark each line using a straight edge. 
7. Cut along these lines, using the jigsaw, so that you have 4 strips of 145 mm and one strip about 115 mm.
8. Take each strip and place them with the inside of the pipe facing down.
9. Make a mark at one end of each strip 115 mm from the left edge.
10. Make a mark at the other end of each strip 30 mm from the left edge.
11. Mark and cut these lines, using the jigsaw.
12. Place each blade with the inside of the pipe facing down.
13. Make a mark along the angled line of the blade, 3" from the wide end.
14. Make another mark on the wide end of the blade, 1" from the straight edge.
15. 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.

Cutting Tail
The exact dimensions of the tail are not important.  You want about one square foot of lightweight material, preferably metal.  You can make the tail any shape you want, so long as the end result is stiff rather than floppy.

Drilling Holes in Square Tubing - using the 5/16” drill bit (Option #1)

1. Place the motor on the front end of the square tubing, so that the hub part hangs over the edge and the bolt holes of the motor face down.
2. Roll the motor back so you can see the bolt holes, and mark their position on the square tubing.
3. Drill a 5/16” hole at each mark all the way through the square tubing.

Drilling Holes in Blades - using the ¼" drill bit

1. Mark two holes at the wide end and along the straight edge of each of the three blades. The first hole should be 3/8 " from the straight edge and ½ " from the bottom. The second hole should be 3/8 " from the straight edge and 1 ¼" from the bottom.  
2. Drill these 6 holes.

Drilling and Tapping Holes in Hub - using the 7/32" drill bit and ¼" tap

NOTE: You may want to modify these instructions.Try replacing the hub with an old, used 7 1/4 inch skill saw blade or an old aluminum frying pan (without the handle). The larger surface area will give you more space to screw or bolt the blades to. I initially used a metal slow moving vehicle sign, reinforced with a ring of wood, to bolt the pvc blades to. This gives you lots of room to work with. We also used 1/4 inch bolts rather than drilling and tapping holes. Later I found this hub to block a lot of wind and replaced it with an old frying pan for a hub.

If the Treadmill motor comes with the hub attached, take it off, hold the end of the shaft (which comes through the hub) firmly with pliers, and turn the hub clockwise. This hub unscrews clockwise, which is why the blades turn counter-clockwise.

1. Make a template of the hub on a piece of paper, using a compass and protractor.
2. Mark 3 holes, each of which is 2 3/8" from the center of the circle and equidistant from each other.
3. Place this template over the hub and punch a starter hole through the paper and onto the hub at each hole.
4. Drill these holes with the 7/32" drill bit.
5. Tap the holes with the ¼" x 20 tap.
6. Bolt the blades onto the hub using the ¼" bolts. At this point, the outer holes have not been drilled.
7. Measure the distance between the straight edge of the tips of each blade. Adjust them so that they are all equidistant.  Mark and punch each hole on the hub through the empty hole in each blade.
8. Label the blades and hub so that you can match which blade goes where at a later stage.
9. Remove the blades and then drill and tap these outer three holes.

Note: the metal slow moving vehicle sign is not solid enough to stand-up in high winds. We screwed on a wooden ring to the back of the sign to give it the required strength. Later, we replaced this hub with a metal frying pan (no handle of course).

Making a Protective Sleeve for the Motor

1. Draw two straight lines, about ¾” apart, along the length of the 3” x 11” PVC Pipe. Cut along these lines.
2. Make a 45º cut at the end of the pipe. 
3. Place needle nose pliers inside the strip that has been cut out, and pry the pipe apart.
4. Making sure the bolt holes of the motor are centered in the middle of the missing strip of PVC pipe, push the motor into the pipe. An extra person will make this a lot easier.

ASSEMBLY

1. Place the motor on top of the square tubing and bolt it in, using the two 5/16” x ¾” bolts.
2. Place the diode on the square tubing, about 2” behind the motor, and screw it into position using the self-tapping metal screw.
3. Connect the black wire coming out of the motor to the positive incoming terminal of the diode (Labeled AC on the positive side).
4. Connect the red wire coming out of the motor to the negative incoming terminal of the diode (Labeled AC on the negative side).
5. Center the tail over the square tubing, at the back end. Clamp your tail onto the side of the square tubing.
6. Using 2 self-tapping screws, screw the tail in place. 
7. Place each blade on the hub so that all the holes line up.  Using the ¼" bolts and washers, bolt the blades to the hub.  For the inner three holes, use two washers per bolt, one on each side of the blade. For the outer three holes, just use one washer next to the head of the bolt. Tighten.
8. Hold the end of the shaft of the motor (which comes through the hub) firmly with pliers, and turn the hub counterclockwise until it tightens and stops.
9. Screw the nipple tightly into the floor flange using a pipe wrench.
10. Clamp the nipple in a vice so that the floor flange is facing up and level.
11. Place the square tubing (and everything that is on it) on top of the floor flange and move it so that it is perfectly balanced.
12. Through the holes of the floor flange, mark the square tubing at the point of balance.
13. Drill these two holes using a 5/32" drill bit. You will probably have to take off the hub and tail to do this).
14. Attach the square tubing to the floor flange with two sheet metal screws.
15. If you select OPTION #2,  I used a rotating dolly or caster, bolted to the top of the tower. The caster needs to have a hold in the middle that you will run the power wires down, through the tower (called a hollow kingpin). This replaces the nipple and flange, which would attach to the motor and the nipple spils inside the tower.

For a longer life span of your wind generator, you should paint the blades, motor sleeve, mount and tail.

I have many more pictures on my website at http://www.greenterrafirma.com/DIY_Wind_Turbine.html

if you need clarification on any of the above.. Or leave comments here!