Motor rattling when spinning

[FlyingDutchman90]

Hello everyone,

When I tried to spin the propellers on all four arms I noticed that on one arm, the propellers are spinning but there is some light resistance. So I had a closer look and it appears that there is a slight rattling noise when I spin the motor. I can also feel that it doesn't spin completely smooth, as if there is some resistance.

Nothing unusual happened during my last flight. I did not take off or land in sandy or dusty area. Does anyone have an idea what might be the problema and how this can be fixed?

Thanks in advance

 

[Yorkshire_Pud]

What drone?
Ooops it's presumably an Air 2s lol, my mistake.
With a Mavic Mini I found one rear motor to be a bit more notchy than the others, I think/recollect I also felt some play in the rotor.
I dismounted the motor from the arm, without distrubing the wiring, so that I could grip the motor's base and spin and wobble the motor's rotor. I could detect not play.
When I remounted the motor I was left with the distinct impression that the screws screwed in farther than they unscrewed, combined with the wobble this leads me to suspect that the motor's mounting screws had come slightly undone.

Can't comment about any noise change.

 

[FlyingDutchman90]

It's the Mavic Air 2S.
Do you know if it's feasible to remove the motors from the Mavic Air 2S?

 

[Yorkshire_Pud]

Yep cottoned on to the thread being in th Air 2s forum, my whoopsie.

With regards to the motors, I do not know but the front arms look similar to those of the Mavic 2 Pro/Zoom and for the M2P/Z one can get access to the front motor mounts by displacing the landing leg but be aware there is a screw that holds the landing leg in place UNDER the LED cover, it's a bit of a beep beep to get to.

From a video of an Air 2s, it looks as if there is a screwed in-place cover over the rear motor mounts but I haven't found a video that shows dismounting either motors.

 

[FlyingDutchman90]

Hmm... That definitely sounds too complicated to even try for me. I think I will have to try and look for a drone repair shop.
Thank you for your comments.

 

[Yorkshire_Pud]

Well you could always just replace the arm and motor, that's a soldering job. I've done that with an M2Z that I tree'ed and it looks like I will have to do something similar with an M2P that took a 3ft tumble the other day, grrrrr.

 

[FlyingDutchman90]

I'm really not that technical so replacing the arm and motor definitely isn't something I would try myself.. I will look for a drone repair shop to see if they could help. Thank you very much for thinking along!

 

[Yorkshire_Pud]

Ahh ok, in that case might I suggest sending it in to DJI themselves for repair?

 

[slup]

Don't really know what you might mean when saying you hear/feel some ''rattling"?

But I guess you know that it's totally normal that a motor will have repetitive resistance due to the spaced magnets inside the motor..? Depending on the distance between the motor bell & the magnets, different motors on the same drone can have a different degree of resistance, spanning from nearly none (rotates very easily) up to very obvious resistance... none of this is a sign of a motor failure.

If you on the other hand hear/feel intermittent roughness & grinding... then a bearing most probably isn't healthy, or the motor bell have been slightly deformed or the shaft have been bent (in a crash?) making the bell touching the magnets.

If it really sound like something is rolling around inside the motor when you rotate it... then it could be some debris inside from a landing or launching on/from a dusty spot... a grain of sand or similar. Try to carefully blow it out with some high pressure canned air in that case.

 

[FlyingDutchman90]

Don't really know what you might mean when saying you hear/feel some ''rattling"?

But I guess you know that it's totally normal that a motor will have repetitive resistance due to the spaced magnets inside the motor..? Depending on the distance between the motor bell & the magnets, different motors on the same drone can have a different degree of resistance, spanning from nearly none (rotates very easily) up to very obvious resistance... none of this is a sign of a motor failure.

If you on the other hand hear/feel intermittent roughness & grinding... then a bearing most probably isn't healthy, or the motor bell have been slightly deformed or the shaft have been bent (in a crash?) making the bell touching the magnets.

If it really sound like something is rolling around inside the motor when you rotate it... then it could be some debris inside from a landing or launching on/from a dusty spot... a grain of sand or similar. Try to carefully blow it out with some high pressure canned air in that case.

with rattling I mean a soft ticking noise.... It's very minor, but I don't want to ignore something with the risk that one day it will just fall out of the sky.
So the other 3 propellers sets spin around very smoothly even if I give them the slightest spin... The propellers on this 4th arm spin around as well, but make a soft ticking noise when they do and you can feel that there is a very minor resistance. It just needs a little harder push to go around.
Also, when I removed the propellers again this morning and I looked inside, there was some red stains on the inside of the propellers, which is not on the inside of the other propellers. It's the exact copper-like colour of the inside of the motor.

There has not been any crash. Debris from landig/launching I cannot exclude. I did try to blow in it with a hair blower in case there was any debris in there, but it didn't change anything. I will try tonight to see what a vacuum cleaner could do...

 

[FlyingDutchman90]

Ahh ok, in that case might I suggest sending it in to DJI themselves for repair?

I think I will look first if there's a drone repair shop that I can visit in person first to at least have an idea what's going on... Because if I send it to DJI I probably will be without it for a while, and I would like to use it again in the near future. But if it's something serious, I could definitely send it to DJI

 

[Yorkshire_Pud]

Fair enough.
I can't comment about noise but I can feel the 'pulsing' that @slup mentions with though it varies from motor to motor. However it is not a harsh sensation and distinctly different from something catching on something.

 

[FlyingDutchman90]

Okay, a little update. So I gave it another couple of minutes with the hairblower and the rattling/slight resistance is gone! The propellers now all go round equally smooth, so I guess it was indeed still a grain of sand that was refusing to come out... I must say, I only have the Air 2S for a couple of weeks. Have been flying the Mini 2 for 1.5 years now and never had any moment that I would even remotely question whether it would function properly, but with the Air 2S I already had several moments that I was slightly worried. Nevertheless, when I see the footage that comes out of it, the Air 2S makes it all worth it. What a fantastic drone.

Thank you very much for thinking along!