There are two quantities of interest for propeller:
- Thrust – [N]
- Torque – [Nm]
In case of propeller, reference pressure is not taken into account when evaluating thrust and torque.
Dimensional analysis leads to a definition of propeller coefficients representing its performance. 8.1
- Torque coefficient ():
- Thrust coefficient ():
where is the propeller speed [rev/s] and denotes the propeller diamater [m].
The efficiency can be evaluated using the supplied power to the propeller ( ) and the useful power output ( ):