Step by step instructions for making your own 4 foot wind turbine
There are several DIY wind turbine science projects on the internet. This project is appropriate for the high school level.
Making a wind generator from scrap materials is very rewarding and empowering. Most of the tools and materials you need can be found at your local hardware store or in the scrap pile. We strongly recommend that you check your local landfill and/or junkyard for the necessary materials. If you live in a city, search for salvage parts at freecycle.org. For the wind turbine built in these pictures, we picked up the motor on eBay for $10 plus shipping and the PVC pipe for the blades from a scrap heap. The tail is made from an old roller paint can.
Safety should be your top priority. Human life is more important than electricity, so please work safely.
This wind turbine is based on the chispito design with its simple and efficient design and assembly.
SUPPLIES
A 260VDC, 5A continuous duty treadmill motor with a 6-inch threaded hub is best suited for a small wind turbine. These engines are available at most engine surplus stores and on eBay. You can get around 7 amps in a 30 mph wind. In other words, it’s a simple and cheap little machine to start with.
I also bought a 90V DC 20A treadmill motor on eBay for $10 plus shipping. This motor requires an upgrade to most of the original Chispito instructions due to the increase in size and weight.
You can use any other single permanent magnet DC motor that puts out at least 1V per 25 rpm and can handle more than 10 amps. If you do, there will be certain changes to this supply list, for example, you’ll need to find a hub – a circular saw blade with a 5/8″ arbor adapter will work. For our larger motor, we used a metal motor slow moving vehicle signal, bolted to a 3.5″ pulley. The triangular shape was just what we were looking for, but it requires support from behind, or the metal bends in high winds. Tools
- Drill bits
- jigsaw with metal blade
- Wrench
- flat head screwdriver
- Wrench
- Bench vise and/or clamp
- wire stripper
- Measuring tape
- Marker pen
- An extra person helps a lot!
Mount
- Square pipe or “L” pipe
- Floor flange – or a rolling wheel with a hole in the center (imagine the wheels in a grocery store
- 4 inch nipple
- 3 x 3/4 self-tapping screws
- Note: If you are using the roller wheel, you will not need the nipple or flange as the roller wheel bolts to the tower.
Engine
- 260V DC, 5A continuous duty treadmill motor with a 6-inch threaded hub
- 30 – 50 amp blocking diode (one way)
- 2 5/16 x 3/4 engine bolts
- PVC tube – to cover the engine
Line
- 1 square foot (approx) lightweight material (metal) – used roller paint tray will work
- 2 – Self-tapping screws 3/4
blades
- 24″ long 8″ PVC pipe (if it’s UV resistant, you won’t need to paint it)
- 6 – Bolts 1/4 X 20
- 9 – washers 1/4
- 3 sheets of A4 paper and tape
cut blades – makes 8 blades (or more than 2 sets of blades) and a thin strip of waste.
Read the instructions a couple of times. I’ve created a separate page, with pictures, and expanded this process to make the blades, as it’s almost impossible to understand without the illustrations. See the link at the end of this article.
- Lay the 24″ long PVC pipe and the square pipe (or other straight edge) side by side on a flat surface. Push the pipe against the pipe and mark the line where they touch. This is Line A.
- Make a mark near each end of line A, 23″ apart.
- Glue 3 sheets of A4 paper together, so that they form one long, completely straight sheet of paper. Wrap this around the section of pipe at each of the two marks you just made, one and then the other. Make sure the short side of the paper is straight along Line A and the paper is flat against itself where it overlaps. Mark a line along the edge of the paper at each end. Call one Line B and the other Line C.
- Start where line A intersects line B. Going left around line B, make a mark every 145mm. The last section should be about 115mm.
- Start where line A intersects line C. Going around line C, make a mark every 145mm. The last section should be about 115mm.
- Mark each line with a ruler.
- Cut along these lines, using the jigsaw, so that you have 4 strips of 145mm and one strip of about 115mm.
- Take each strip and place them with the inside of the pipe facing down.
- Make a mark at one end of each strip 115mm from the left edge.
- Make a mark at the other end of each strip 30mm from the left edge.
- Mark and cut these lines, using the jigsaw.
- Place each blade with the inside of the tube facing down.
- Make a mark along the angled line on the blade, 3″ from the wide end.
- Make another mark on the wide end of the sheet, 1″ from the straight edge.
- Connect these two marks and cut along the line. This prevents the blades from interfering with each other’s wind.
sand the blades
You must sand the sheets 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 (tail) edge wants to be pointed. Sharp corners should be rounded slightly to reduce noise.
cutting the tail
The exact dimensions of the tail are not important. You want about a square foot of lightweight material, preferably metal. You can make the tail any shape you want, as long as the end result is stiff rather than floppy. Drilling holes in square tubing with the 5/16″ drill bit
- Position the motor on the front end of the square tube so that the hub portion hangs over the edge and the motor bolt holes face down.
- Back the engine up so you can see the bolt holes and mark their position on the square tube.
- Drill a 5/16″ hole at each mark along the length of the square tube.
Drilling holes in blades – using the 1/4″ bit
- Mark two holes at the wide end and along the straight edge of each of the three sheets. The first hole should be 3/8″ from the straight edge and 1/2″ from the bottom. The second hole should be 3/8″ from the straight edge and 1 1/4″ from the bottom.
- Drill these 6 holes.
Drilling and tapping holes in the hub – with the 7/32″ drill bit and the 1/4″ tap
NOTE: You may want to modify these instructions. Try replacing the hub with an old, used 7 1/4-inch professional saw blade. The larger surface area will give you more room to bolt or bolt on blades. The larger the blades, the more important this connection becomes. For our larger motor, we used a metal slow moving vehicle sign, reinforced with a wood ring, to bolt on to the pvc blades. This gives you plenty of room to work. We also use 1/4 inch bolts instead of drilling and tapping holes. I have also seen old aluminum pans used for this purpose. They are light and solid!
- If the hub is attached to the treadmill motor, remove the hub, firmly grasp the end of the shaft (which passes through the hub) with pliers, and turn the hub clockwise. This hub unscrews clockwise, so the blades rotate counterclockwise.
- Make a template of the cube on a piece of paper, using a compass and protractor.
- Mark 3 holes, each 2 3/8″ from the center of the circle and equidistant from each other.
- Position this template over the center and punch a starter hole through the paper and into the center of each hole.
- Drill these holes with the 7/32″ drill bit.
- Tap the holes with the 1/4″ x 20 tap.
- Bolt the blades to the hub using the 1/4″ bolts. At this point, the outer holes have not been drilled.
- Measure the distance between the straight edge of the tips of each blade. Adjust them so they are all equidistant. Mark and drill each hole in the hub through the empty hole in each sheet.
- Label the blades and the bucket so you can match which blade goes where at a later stage.
- Remove the blades and then drill and tap these three outer holes.
Note: A metal slow moving vehicle sign is not strong (thick) enough to stand upright in high winds. We screwed a wooden ring onto the back of the sign to give it the necessary strength.
You now have all the parts you need. For final assembly instructions (and a review of previous instructions with a lot of pictures) please have a look at this website: http://www.greenterrafirma.com/DIY_Wind_Turbine.html.
includes several more photos to help with final assembly and an additional section on Torres. These plans are provided free of charge.
Enjoy!