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Verticle Axis Wind Turbine Materials? Answered

I've been working on a vertical axis wind turbine that uses uses 3 identical helical blades positioned around a central vertical axis. For small working models I've been using 16 gauge wire and cardstock. I'm looking to build one with 6-8 foot blades. The trouble is finding an ideal material for this. It needs to be lightweight, cheap, flexible, "malleable" (it needs to be able to be bent into a helix but then retain the shape), and come in a 4'x8' sheet. PVC/CPVC is super expensive, as is polycarbonate, and aluminum. Any suggestions? 


What is your idea of cheap in this case?

How do you plan to get the material into the shape you need?

IMHO this kind of a project would be better served if you take your time to save up the money needed to get the right material for the job. In this case aluminum is your best choice if you are able to work with it and get it bent into shape. Otherwise polycarbonate is the best option as far as weight and the ability to work with it. All you will need is a wood form in the shape of your blade to lay the poly across then start heating it evenly with several people running heat guns till is falls into shape and cools in that shape.

I have all the jigs and forms worked out. I would like to use aluminum, the problem is that with aluminum, I need to also create a skeleton. Like an airplane wing. With the polycarbonate, It would be lite enough yet rigid enough to be used with minimal support. The issue Is cost, Polycarbonate sheets the size that I need seem to go for upwards of $150. I may just have to embrace the cost and save up a little. Still my idea of cheap is a recycled, close substitute, preferably only costing me in labour.

See what you can find in your area in the way of orange construction barrels, blue 50 gallon plastic barrels and even old portal-potties. The plastics used in these can be formed with heat and should be easily obtained with minimal cost.

Do you have a good straight shaft to mount all of this too? How do you plan to mount the blades and couple them to the motor?

You will want the weight of the turbine on a good shaft and have that shaft supported on the top and bottom so the full weight and torque of the turbine spinning isn't directly on your motor wearing out the bearings or bending the shaft of the motor. Even with a fairly light weight turbine you'll be putting a lot of strain on the motor if it isn't well supported. You also need good bearings on the supports of the turbine. A straight iron pipe will work but you will need to find a good way to couple your motor shaft to the turbine shaft.

The idea is to design an outer shell around a central axis, essentially a pipe inside of a slightly larger pipe. The outer pipe bears the weight and the inner pipe is fixed to a set of arms that support the blades. These arm assemblies look like a wheel with three spokes. I'm considering how to rest them on the outer shell. I have lots of ball bearings lying around (from skateboards), so It'll probably involve those in some way.

Thin plywood can do that - make it in two layers, then glue & clamp the layers in shape until they dry.