This instructable is an entry in the 2012 Make It Real Contest.
The goal of this instructable is to create a reduced drag VAWT (vertical axial wind turbine) out of household materials.
Note that this is not the entire engine to generate electricity, but just the blades of the turbine to be used alongside a generator (my current design is based off of Hugh Piggott 5 phase 240 Hz generator). I am not including that part of the instructable because it can all be found through his research and he deserves the credit.
The idea behind this concept was derived from an instructable on how to make a reduced drag VAWT where the blades rotated to create either the best lift or the least drag. I wanted to go for something more simple, easy to understand and have as few mechanical parts as necessary, with the overarching goal to be made from everyday materials (no fabrication needed). From my descriptions of the concept Ceara Byrne was able to provide the design, help, and motivation for this project, and without her I could not have done this.
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Step 1: Materials
The following materials are required:
Soda cans (preferably washed out, a 12 pack will be sufficient)
Adhesive agent (I used Gorilla Glue after solder failed me and apoxy made too big of a mess)
Cutting utensil (orignally a box cutter was used but this was traded in for an xacto knife)
Fishing line (I used 12lb test as it was on hand, and I was sure it didn't need to be stronger for my purposes)
The following materials are recommended:
Dissolvent (if you don't want to deal with your adhesive)
Spray paint (if you want a fancy colored/designed turbine)
Step 2: Tracing and Cutting
The cans need to be cut into the blades.
To make this process easier, first trace the cuts with your knife.
To make that process easier, use the masking tape to mark off the lines needed.
The vertical lines should be on opposite sides of the can, with one start from the middle of the mouth (the drinking area).
The horizontal lines should run just below the top curve of the can, and just above the bottom curve.
Only trace on one side of the tape vertically.
Next trace along the top and bottom edges from the vertical trace until the other masking tape is reached.
Then do this again for the other side of that piece of tape.
Once all of the cuts have be traced out, then proceed to cut.
You do not need to do this part with much force, especially if you have done the tracing part correctly because the can will just start to peel in as you go.
I found it easier to do the bottom and top cuts first and then do the vertical one.
Be careful when cutting. The precuts help keep the edges from being sharp and jagged, and they also make the cuts cleaner and better looking.
After the cuts have been done, go ahead and fold back the can.
Don't worry about being too forceful with the bending, the metal can easily be bent back and forth as needed.
Step 3: The Innards
There are two ways to do this step, one is more difficult and more dangerous and has little extra benefit other than using only one can. The other is to harvest the part of another can. I am going to outline the difficult route and interject the easier part when it comes.
First, take the tab off the top and bend it so that the longer part lies flat and the shorter part sticks up.
Then use your adhesive to secure the tab to the bottom of the can, and make sure to angle it so that the opening lines up with the vertical edges.
Next punch a hole in the folded down lip of the can, the part that goes in when you open the can. This is the difficult part. It is much easier/safer to fold the lip back up and just use another tab from another can, but now that can will need two tabs.
If you go the difficult route, it is easier to punch the hole first, and then glue the lip into place so that the hole lines up with the edges just like the tab did.
Step 4: The Blades
This part can be dangerous, so be careful and watch what you are doing.
Now you will punch holes in the blades.
These holes will be about a centimeter from each edge, and can be as big as necessary.
I found it better to punch the hole from the outside of the can, and once the knife was through, to turn the blade downwards so it would fold the puncture inwards making it less hazardous to snag you while working.
After the holes are punch, thread the fishing line through and tie it off so that the knots are on the outermost vertical edge.
To ensure that the knots stay, I added more adhesive here.
Next string out the fishing line across the can and cut it (you won't need any more than that).
Then thread the line through the tabs/holes from the last step.
Before you tie them off on the other side of the can, fold this side in and tape it so it stays folded in during the process. This will give tension to the line so when one side opens, the other closes.
Then go ahead and tie off the other side, apply some more adhesive and trim the excess.
Step 5: Final Step
At this point you should be ready to use your adhesive to stick all the cans together in a tower formation.
Luckily the cans are created so that they stack nicely on top of each other.
Be sure to stagger the blades, so that one will always be catching the wind.
And now your VAWT blades are ready to be attached to your turbine.
Currently I am working on attaching them to the fly wheel of a bike so that I can use the gears to my advantage.
At low wind speeds there won't be much change in the shape of the blades, but at speeds over 5 mph, the cans will start to catch and open, which means that the otherside will be closing, thus reducing its drag as it spins around! And the best part is, it is self directing, so as the wind changes direction, the cans will still open correctly!
I hope you enjoyed this instructable!