Ok I have a design project that I am working on for the University this semester. Having a bit of problems trying to figure out and issue revolving around the wind force on our savonius blades. We are trying to make sure our blades will rotate with a wind speed of 10 mph. We have the blade total weight of approximately 75 lbs and are 6 feet tall by 4 feet wide. The bearings that the blades will be sitting and rotating on are tapered roller bearings, a set of two. I have read some where that my coefficient of friction for these bearings is around 0.0018 but to cover our selves I would like to use 0.05 Any formulas or directions on how to calculate this not just at 10 but other wind speeds would be wonderful.