I took the rotors off the motors on my Phantom 2 Vision+ Version 3 and then twisted each armature one by one. Two of them felt the same as far as the amount of force it took to twist, and the other two took considerably more effort. The magnetic attraction of the field on the armatures of two of the motors is much stronger. My question is, wouldn't that make a big difference in the way the motors run when under power, and if it does, wouldn't that make the Phantom harder to control? Or, are the ESCs able to compensate for any differences in the power level of each motor? The harder to turn motors are the ones with the black dot props. The Phantom seems to fly ok, so maybe I'm being overly curious.