Seven types of model rotors and the real rotor are studied by experimental and calculating method.

Preferably, the hub has a diameter of between 40% and 50% of the diameter of the rotor, measured at tips of the blades, and is solid so as to prevent air passing through the hub.

Actuator disk theory yields equation (a) above for turbine maximum power, however, actuator disk theory does not yield the rotor geometry without further design theory.