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my problem is that I can’t find a way to calculate the power required to drive the shaft and thus decide on a motor, I have tried several times using different methods and calculations but can’t seem to get a power requirement that would seem accurate, most recently I tried using a fluid equation of force on an immersed body travelling through a fluid using integration I got formula for torque, on each of the paddles rotating in the hopper of 1/8*Coeff drag*density*angular velocity^2*width of paddle*radius of paddle^4 and adding the inertia of the system, this gave me a power requirement of a 150 watts which seems ridiculous, I was wondering how i should go about calculating the power requirement. Any help would be greatly appreciated. Thanks ollie

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closed as off topic by Qmechanic, Manishearth, Emilio Pisanty, Waffle's Crazy Peanut, Sklivvz Dec 27 '12 at 16:00

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Related: – Qmechanic Nov 6 '12 at 14:17