Drag Spinning

How Savonius Wind Turbines work?

How does it spin, int terms of drag, and power stroke and return stroke? Also, the involution blades around the axis to do better? What about the height of the shoulder blades? All links would also help to

I have answered this question about an hour ago -- no question of the search savornius

American Drag - "Spinning"

[affmage source="ebay" results="6"]Drag Spinning[/affmage]