Brushless Motor Size Comparisons Chart
One thing I’ve found with RC aircraft is that there are two different ways of measuring a motor size. Manufacturers who mainly produce, or started by producing, quadcoptor motors base the sizes on the stator. Whereas manufacturers who have traditionally made motors for RC planes use the external dimensions (the diameter of the bell by the length from the flat of the base to the flat top of the bell). I’ve produced a table to show the two side by side to make it easier to find motors.