Inspire 2 whistling sound

wisnia1010 · Sep 4, 2018

Hi there !
First of all, i'm from Poland, so sorry for my English, but i'll try to do my best

Today i recieved my Inspire 2 (finally !).
I'm waiting for the X5S gimbal, so i tried it out without camera attached to the bird.
I noticed that there's a high-pitched whistling sound when I2 is in the air. It dissapears, when I2 sits on the ground with turned on motors, but when it comes up the sound is back.
Does anybody had similar experience ? Props are locked tight, there's no deviations and weird sounds when i turn the motors with hand, so i have no idea what could be the reason for this noise in the air ?
Or maybe it's normal ?
Thanks in advance for any advise

slim.slamma · Sep 4, 2018

wisnia1010 said:
Hi there !
First of all, i'm from Poland, so sorry for my English, but i'll try to do my best
Today i recieved my Inspire 2 (finally !).
I'm waiting for the X5S gimbal, so i tried it out without camera attached to the bird.
I noticed that there's a high-pitched whistling sound when I2 is in the air. It dissapears, when I2 sits on the ground with turned on motors, but when it comes up the sound is back.
Does anybody had similar experience ? Props are locked tight, there's no deviations and weird sounds when i turn the motors with hand, so i have no idea what could be the reason for this noise in the air ?
Or maybe it's normal ?
Thanks in advance for any advise

Return it immediately and get new one!

wisnia1010 · Sep 4, 2018

Well, if i won't find the source of this sound i'll be probably forced to sending it back

It sounds very similar to P3 from this video:

The Editor · Sep 4, 2018

wisnia1010 said:
Hi there !
First of all, i'm from Poland, so sorry for my English, but i'll try to do my best
Today i recieved my Inspire 2 (finally !).
I'm waiting for the X5S gimbal, so i tried it out without camera attached to the bird.
I noticed that there's a high-pitched whistling sound when I2 is in the air. It dissapears, when I2 sits on the ground with turned on motors, but when it comes up the sound is back.
Does anybody had similar experience ? Props are locked tight, there's no deviations and weird sounds when i turn the motors with hand, so i have no idea what could be the reason for this noise in the air ?
Or maybe it's normal ?
Thanks in advance for any advise

Normal.
There is also nothing wrong with the Phantom in the video you posted.

Mark Titcombe · Sep 5, 2018

That's a weird one, I can't say that I've heard that high pitched whistle on any drone I've ever used, certainly neither of my i2's make that sound.

Mark

wisnia1010 · Sep 5, 2018

The Editor said:
Normal.
There is also nothing wrong with the Phantom in the video you posted.

That's why i'm confused. I searched that topic on the web, and basically everybody, who experienced that sound in their copters, claims that's normal and doesn't have any influence to flying or motors life time, but, in that case, what's the reason of that sound ? Never had that experience with any of my former drones, so this is something new to me.

The Editor · Sep 5, 2018

wisnia1010 said:
That's why i'm confused. I searched that topic on the web, and basically everybody, who experienced that sound in their copters, claims that's normal and doesn't have any influence to flying or motors life time, but, in that case, what's the reason of that sound ? Never had that experience with any of my former drones, so this is something new to me.

DJI use poor quality bearings (they always have done) and the ones utilised in the I2 are no different. They are cheap Chinese bearings and have poor manufacturing tolerance.
The noise or ringing occurs on many airframes but not all and is race noise in rolling bearings. This occurs when the raceway and rolling elements contact each other. The higher the viscosity of bearing lubrication, the lower the sound, Eliminating this noise entirely is not possible, but it can be minimized by improving the quality of the bearings.

wisnia1010 · Sep 5, 2018

The Editor said:
DJI use poor quality bearings (they always have done) and the ones utilised in the I2 are no different. They are cheap Chinese bearings and have poor manufacturing tolerance.
The noise or ringing occurs on many airframes but not all and is race noise in rolling bearings. This occurs when the raceway and rolling elements contact each other. The higher the viscosity of bearing lubrication, the lower the sound, Eliminating this noise entirely is not possible, but it can be minimized by improving the quality of the bearings.

So, summarizing, beside that sound i shouldn't have to worry about overall efficiency and there's no need to send this I2 back ?
BTW, i made short video, so maybe it will clear up the situation

slim.slamma · Sep 5, 2018

The Editor said:
DJI use poor quality bearings (they always have done) and the ones utilised in the I2 are no different. They are cheap Chinese bearings and have poor manufacturing tolerance.
The noise or ringing occurs on many airframes but not all and is race noise in rolling bearings. This occurs when the raceway and rolling elements contact each other. The higher the viscosity of bearing lubrication, the lower the sound, Eliminating this noise entirely is not possible, but it can be minimized by improving the quality of the bearings.

From the i2 in the second post that’s the bearings?

Must be I guess, different drones same noise.
Keeping secrets again I see?
I’ve been kicking myself in arse for not returning mines in 7 days, for months now.

slim.slamma · Sep 5, 2018

The Editor said:
DJI use poor quality bearings (they always have done) and the ones utilised in the I2 are no different. They are cheap Chinese bearings and have poor manufacturing tolerance.
The noise or ringing occurs on many airframes but not all and is race noise in rolling bearings. This occurs when the raceway and rolling elements contact each other. The higher the viscosity of bearing lubrication, the lower the sound, Eliminating this noise entirely is not possible, but it can be minimized by improving the quality of the bearings.

**** boss I actually went down to their NYC store and cursed them people out and come to find out it’s the bearings. I assumed it was gimbal.

**** I feel bad now

whimike · Sep 5, 2018

wisnia1010 said:
So, summarizing, beside that sound i shouldn't have to worry about overall efficiency and there's no need to send this I2 back ?
BTW, i made short video, so maybe it will clear up the situation

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Might be normal, but of all the I2's that I have flown I have not heard this sound. If you don't like it, I would return it. If you can deal with the sound then keep it.

wisnia1010 · Sep 6, 2018

Well, i was waiting for that copter for a long time, and really don't want to wait for another few weeks for the repair/replacement.
This sound is something i can live with, but does this poor manufacturing tolerance of the bearings can happen that drone will fall down ?
I had read somewhere that those bearings should handle about 100 hours in the air, but in my case, probably, that will be not very true.

The Editor · Sep 6, 2018

wisnia1010 said:
Well, i was waiting for that copter for a long time, and really don't want to wait for another few weeks for the repair/replacement.
This sound is something i can live with, but does this poor manufacturing tolerance of the bearings can happen that drone will fall down ?
I had read somewhere that those bearings should handle about 100 hours in the air, but in my case, probably, that will be not very true.

Bearings will be fine.
Don't worry - go fly.

wisnia1010 · Sep 7, 2018

The Editor said:
Bearings will be fine.
Don't worry - go fly.

That's what i'm going to do

Thank you all for your help, and i wish safe flights to all of Inspire freaks

PeterFranken · Sep 8, 2018

You are flying very low with gear up. The alarm sound like the Security signals. No problem fly the I2

Photoflyboy · Sep 8, 2018

wisnia1010 said:
That's what i'm going to do
Thank you all for your help, and i wish safe flights to all of Inspire freaks

I'd send it back. You paid good money for that copter don't settle for anything less. That noise will drive you crazy over time, you can wait 2 weeks for something you will use for years, and you will probably have to send back anyway.

Donnie Frank · Sep 9, 2018

wisnia1010 said:
Hi there !
First of all, i'm from Poland, so sorry for my English, but i'll try to do my best
Today i recieved my Inspire 2 (finally !).
I'm waiting for the X5S gimbal, so i tried it out without camera attached to the bird.
I noticed that there's a high-pitched whistling sound when I2 is in the air. It dissapears, when I2 sits on the ground with turned on motors, but when it comes up the sound is back.
Does anybody had similar experience ? Props are locked tight, there's no deviations and weird sounds when i turn the motors with hand, so i have no idea what could be the reason for this noise in the air ?
Or maybe it's normal ?
Thanks in advance for any advise

A bad bearing will cause the kind of noise you describe. That noise creates friction which will cause undue current draw. The latest DJI offerings are equipped to warn users via the Go 4 App when a motor pulls too much current. I would conduct many test flights to "shake down" whatever issue this may be. You might even try to put the bird under a load. Bonus points for examining the log files, which should tell you how much current each motor is drawing (may be measured in voltage, but should be measured in "Watts" or "Amps"). If this were my bird, I wouldn't hesitate to examine the log files. If you find an anomaly, you can use it as proof that the bird has a flaw.

Good luck.

The Editor · Sep 9, 2018

It is NOT a bad bearing. It is quite normal on many many DJI airframes which utilise Chinese bearings.
If you are concerned about bearings, forget apps, log files or any other useless 'aids' which will only alert you when things are already past the point of bad wear.
The simplest and most effective test is to place your finger on the bell housing of each motor immediately upon landing to feel the warmth of each one. If one feels warmer to the touch than the others then it can indicate the start of bearing wear.

Donnie Frank · Sep 9, 2018

The Editor said:
It is NOT a bad bearing.

Then what is making the whistling sound?

The Editor said:
It is quite normal on many many DJI airframes which utilise Chinese bearings.

I've owned dozens of aerial vehicles. None have ever whistled.

The Editor said:
If you are concerned about bearings, forget apps, log files or any other useless 'aids' which will only alert you when things are already past the point of bad wear.

Actually, before a motor blows up, it will draw too much current for quite a while. It will also heat up. There are a few precursors to catastrophic failure. I think we can all agree that checking log files certainly doesn't hurt. Agreed?

The Editor said:
The simplest and most effective test is to place your finger on the bell housing of each motor immediately upon landing to feel the warmth of each one. If one feels warmer to the touch than the others then it can indicate the start of bearing wear.

Sure. But log files are objective. "Touching" is somewhat subjective. I would actually recommend an IR temperature gun. In lieu of that, the log files become your best friend.

wisnia1010 · Sep 9, 2018

Thanks guys for all advices.
Of course, i can take log files from the I2, but for me it's black magic to read them in advanced way, so could somebody help me sort out what that files indicates ?