title_body: What is the performance difference between a brushless motor with a wider vs taller stator? In the drone motor industry, there are a lot of variations in the stator sizes of brushless motors. There are several motors that have similar stator volume but one is wider and the other is taller. What are the inherent differences in performance between a drone motor that is wider stator vs one that has a taller stator with a similar stator volume? Would the stator shape influence which props it should use?
upvoted_answer: The simple answer is "more width equals more torque". 
  
  More torque let's you drive a higher pitch or larger diameter prop effectively. Given the same size prop, it will drive it with more effectiveness. Added torque allows the prop to spin up or slow down faster, which ultimate results in a better flying quad because it can more quickly and accurately respond to your stick inputs.
  
  In the miniquad community, this is the reason a lot of freestyle pilots trend toward wider motors on a 5" prop compared to racers. It provides a higher level of smoothness because of how it reacts.
  
  Another effect of more width is more efficiency especially with big crafts that are targeting flight time. You'll see lots of the big (15" or larger) propeller quadcopters with very wide motors. For instance a 5010 stator size. High performance isn't usually the goal here so a wider stator allows them to drive the big prop without lots of excess weight and power that they don't need.
  
  Oscar Liang also has a good concise explanation of different motor stator sizes here
  
  This is an endurance quad I built years ago with the 5010 motors I mentioned. Just to give you an idea of the scale and the uses of a very wide motor.