Low level Beeping tone coming from M2 Pro

[Crouching Leopard]

This is a bit different but its driving me nuts. I had my Mavic 2 pro replaced for a new unit 3 weeks ago. I have noticed this high pitched beep coming from it whenever its in flight. Its not an alarm or coming from the controller, and it only happens when the drone is in flight, even hovering low near the ground or moving through the air. If the props are spinning but the drone is not flying, its not there. I have disabled the sensors and landing detection, turned off the bottom lights and everything else I can think of. The amplitude is uniform all around the drone. Its driving me nuts trying to figure it out. Does anyone else hear this on their M2 pros or other drones. To hear the tone, mentally filter out the regular prop noise and listen for something that resembles a truck reversing. I can hear it from 10-20 metres away although this was recorded from about 1 metre, hovering about 2 metres off the ground. Its still there if the drone is 20 metres of the ground.

 

[MA2 317]

I hear it too on your video.

I don't have the aircraft but you might try changing the props.

If that doesn't do it, check the sound from each motor while hovering in front of you best you can.

There might be a motor that's spinning up and vibrating enough to cause the frequency, since it's a replacement drone.

 

[old man mavic]

it could be coming from the internal cooling fan as it spins or one of the motors

 

[Crouching Leopard]

Thanks for the replies. I have been in contact with DJI and they are investigating the sound. I did ask them if it was a new drone when they offered a replacement. The "confirmed" it was factory new but I have my suspicions as it did not come in a box. I am getting over DJI a bit as this a 3 week old replacement for a new drone which developed gimbal problems after a few hours flying. That drone was a replacement for one which, at a year old, developed stress fractures at a well known (as it turned out) weak point in the drone body. I have also had 3 bulging batteries (caused by iron particle contamination on the production line), 2 of them with less than 100 charges on. I fly at least an hour every day commercially and have had to turn down jobs. Its getting to the point I am not trusting them when doing my commercial work. Admittedly I have never had an issue getting replacements but am getting over raising claims and sending in to. DJI drones are great technology, but I am beginning to think their QC has gone down.

 

[Crouching Leopard]

MA2 317" data-source="post: 1557099" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">

I hear it too on your video.

I don't have the aircraft but you might try changing the props.

If that doesn't do it, check the sound from each motor while hovering in front of you best you can.

There might be a motor that's spinning up and vibrating enough to cause the frequency, since it's a replacement drone.

That recording was taken from less than a metre away. Good suggestion but I dont think I will get any closer

 

[Crouching Leopard]

Got in contact with DJI chat tech support. What they say makes sense. I thought it might be of interest to others post their comments / advice:

"This is due to a difference between motor part dimensions and their respective assemblies. Each motor runs a bit differently, which means that they generate different sounds. As such, some sounds may be mistaken as “abnormal noises”.

"Each aircraft has gone through strict tests before it is shipped out from the factory and meets the ex-factory standards. Please feel free to use your product worry-free."


"Let me also provide you scenarios to determine whether a motor is malfunctioning or not?

A motor is deemed to be malfunctioning when the product your received have any of the following issues:

(1) The motor does not rotate after your product is powered on.
(2) A motor error is reported by the app.
(3) The motor is obstructed or stalled.
(4) The motor becomes obviously hot after running for 15-20 seconds without payloads (without mounting propellers).
(5) The motor produces an extremely sharp noise when idle after the aircraft is mounted with propellers.

"Those are typically the list of things that you need to look out for if the motor is having issues"

"There are also 3 reasons as to why you might be having that noise"

(1) Electromagnetic noise: Noise produced due to motor structure vibration from the motor’s alternating magnetic field;
(2) Mechanical noise: Noise produced due to bearing operation and motor vibration when the motor is running;
(3) Aerodynamic noise: Aerodynamic noise produced due to the impact and friction of air inside the motor when it is running.
In most cases, “abnormal noise from the motor” is a kind of perceptual noise when the sound produced by friction from bearing rotation is amplified by aircraft arms when the motor is running.

"Alright. Rest assured everything is fine with your drone"


So, I will just keep on eye on things but it seems that it could be a normal sound I just haven't heard before.

I will say, I was pleasantly surprised that I got a response so soon and that the guy went into much detail. Thumbs up on this one DJI

 

[Starz]

Sounds like some form of oscillation. Factory props?

 

[KB9Radio]

Apparently it's in a range that I can't hear, it sounds perfectly normal to me.
I don't know

 

[Crouching Leopard]

Sounds like some form of oscillation. Factory props?

Yes. I never use 3rd party. I changed the props yesterday and its still there.