The prop length and pitch create a majority of the load the motor must deal with, the weight is a minor factor. For example:
- a 10" prop will have less drag, and therefore load, than a 14" prop IF THE BLADES HAD THE SAME TWIST(pitch) TO THEM
- a prop with a 3" pitch(theoretical distance the prop will move forward for each full 360 degree rotation) will have less drag than a prop with an 8" pitch IF THE PROPS ARE THE SAME LENGTH
- Now is where things get fun. An 8" prop with an 8" pitch could have less drag than a 14" prop with a 3" pitch.
Thus, it is the drag of the prop that determines how much of an effect there will be on the motor. More drag means more power is needed to turn the prop at a given RPM. To get that increase in power to turn a higher pitch or longer prop, you need to increase the watts(volts times amps) to keep the RPM the same. If you want to turn a prop with less pitch or shorter blades, you can reduce the watts in the same way to keep the RPM the same. The only way to find out how much a prop will affect the motor, ESC and battery pack(s) is to test the combination and see