P4P Motors. Smooth or ratchet?

JeffreyS · Nov 14, 2019

Inspecting my P4P for a flight tomorrow, I noticed that one of the four motors spins by hand with a slight ratchet sensation, while the other three spin freely and smoothly. So I looked at my other P4P and all four have the slight ratchet feel. I never noticed this before but I was not looking for it either. Last flight on each was just fine. Hard to believe that the ratchet condition would not affect performance. Anyone know about this? Thanks.

Meta4 · Nov 14, 2019

JeffreyS said:
Inspecting my P4P for a flight tomorrow, I noticed that one of the four motors spins by hand with a slight ratchet sensation, while the other three spin freely and smoothly. So I looked at my other P4P and all four have the slight ratchet feel. I never noticed this before but I was not looking for it either. Last flight on each was just fine. Hard to believe that the ratchet condition would not affect performance.

You wouldn't have a mystery fault develop in all 4 motors at the same time.
It's normal to feel the magnets affect on the steel part of the armature as you turn the motors.

JeffreyS · Nov 14, 2019

Meta4 said:
You wouldn't have a mystery fault develop in all 4 motors at the same time.
It's normal to feel the magnets affect on the steel part of the armature as you turn the motors.

OK, that's a good explanation. Then why not on all the motors? Some have no magnet effect.

Starz · Nov 15, 2019

Not sure how you are checking the spin on these. Two different ways that I use is with props on and props off. I think the prop on method seems more visible. With the prop on the motor, rotate the prop by a slight push with your finger from the far end of the prop. You should be able to see the magnet effect as the prop will tend to jump ahead slightly. By rotating the motor with two fingers with props off, it‘s movement may not be as obvious. This can be tricky with small diameter motors.