Clarify prop cx

In the propeller documentation, there are two properties which are the “Value of propeller cx” (prop_cx_min, prop_cx_at_cruise_beta).

However, nowhere does it state what Cx refers to in this case, and the effect that this value will have on the rpm/torque/thrust produced. Searching for a meaning of this provides alot of conflicting information, some places use this to refer to drag coefficient, others as the coefficient of excess thrust, and others as the “universal dimensionless parameter”.

Please clarify as to what prop Cx actually means, and the effects it will have on the flight model, thanks