I'd like to know how to work out the drag coefficient of a sheet of cardboard. I know the formula, but to get it you need the drag force which in turn needs the drag coefficient. For reference, the cardboard is about 3mm thick and is roughly 60cm by 20cm. It has a 100g weight attached to the bottom and is sort of in the shape of a propeller. Can anyone tell me how to work out the drag coefficient or tell me what it would be? Also, the "propeller" has slots in it and has angles of attack sort of like flaps on an aeroplane, would the angle of attack have an effect on the coefficient? Thanks!