A friend reminded me of a project that I helped him with 25yrs ago. The class was Intermediate Technology, a course to help understanding of ways to improve developing countries that don't have the highest levels of infrastructure.

Here is how I remember his project to build a Savonious Windmill:

• 'borrow' garbage can from engineering bldg

• saw cut the bottom off & slice into two halves

• bolt onto 'found' pipe for center axle

• create frame, mount top eccentric cam

• made water piston (I forget materials used but remember a good seal / pull of water)

• made check valve (I remember a ping pong ball, but probably a foosball)

• pump water!  it worked but check valve let water flow back upstream.....if I knew then what I know now: tangent to check valves