At the moment I am struggling with the problem that I do have an idea how to calculate this force by using the blade element theory and going over a whole propeller blade in order to calculate the torque inside the blade. I need this torque in order to calculate the force necessary for changing my pitch inflight. Is the blade element theory the correct way to calculate this?
Source: Nelson, Wilbur C.: Airplane Propeller Principles (John Wiley & Sons, 1944).
Also I do lack information regarding the airfoil data. Is there a good estimate on how high the coefficient of torque will be? Is there a good airfoil database for propellers online?
The assumption that cm=-1/4*ca does not work, as profiles on propellers are not even plates.