Small wind turbines have lower energy output than commercial wind turbines, such as those found in wind farms. Commercial generators in the 5-50W range are available for boat or caravan use.
While this particular model is made from a 24 oz. water bottle larger models with blades cut from a 2 or 3 liter soda bottle and using a cardboard, plywood or sheet metal end pieces should be efficient enough to drive a generator based on a fan motor such as those found in old CPU cooling units.
A 12V .09A CPU cooling fan connected to this assembly could produce as much as 1W under the right wind conditions. This is more than sufficient to recharge NiCad batteries and other trivial energy needs, or fed into an existing inverter as a supplemental power source.
With some scaling and good gearing it should be possible to reach as much as 25W using this basic design.
I would like to thank rhackenb for his most excellent and inspirational 'ible Cardboard Savonius Wind Turbine
With that in mind lets get started....
Step 1: Bill of Materials
A protractor - That thing for drawing circles
A compass - The half circle that comes in the package with the thing for drawing circles
A soda bottle. Almost any size will do and the directions will scale up or down as available. I used a 24 oz. water bottle.
Something to use for an axle. I didn't get fancy I used a wooden skewer from a pack of 100 we had in the drawer. Future designs which are used to power generators will probably have a two part axle ( top and bottom ) and not carry the extra weight in the center.
A couple of paper plates or other cardboard for use as the end pieces