With prop driven airplanes, there are basically two types:
* larger airplanes which are turboprop driven, which means a jet driven, constant-speed prop. The blade angle is automatically controlled by the prop governor, and the cockpit power lever(s) control the amount of fuel being fed to the engine, and thus the power output.
These sorts of setups have several safety mechanisms to stop the prop blade angle getting to low and thus having the airflow driving the prop to any large degree.
The actual blade angle is an unknown quantity, dependant on forward t/airspeed and power lever setting.
On the ground, both the blade angle and the fuel supply are directly governed by the power lever(s).
* smaller airplanes with piston driven props are quite different, their prop blade angle is directly controlled from the cockpit to utilize the limited engine power available, in the way that's mentioned, low b/angle with high rpm for takeoff and landing, for extra pulling power, and a higher b/angle and lower rpm for criusing, to get better fuel economy.
Cheers...FD...
