Originally Posted by flying-llama
Related to the timing is that the brushes on some motors are angled to spin more easily in one direction than the other (pulling on a brush, as opposed to pushing on a brush). A picture is in post 1076 of this thread:
I have seen several references to the brushes being designed to work better in one direction and I have to say that I don't buy it. I doubt that it matters which end the support is on.... ie., whether the brush is "pushed" or "pulled". At the brush/comm interface, the brush is just a flat bar of metal in contact with the side of a cylinder. I don't think it matters which way the cylinder rotates. IMO, anyway.
I suspect the real issue is how well the brushes are timed. My CCW motor that has lasted a long time as a CW motor may well be either timed wrong or neutrally timed. I never bothered to measure it, I just installed it. CCW motors that do not last long as CW motors may well be correctly timed for their intended direction of rotation and therefore worse in reverse. The key may be that they are not consistently timed in the first place. My originals definitely were not.
I've kinda backed away from the issue because my one CW motor is doing OK as is the CCW motor used as a CW motor. I fly outdoors just about every time I go out and fly my planes, and that is harder on the motors than flying indoors was.
If motor failure is still an issue for some, maybe it would be a good idea to measure the timing for each motor and use them in their actual favored directions?