Hi there,

I've recently built my very first quadcopter and been experiencing some Issues with the motors.
I've noticed a ratteling sound while flying for the first time and assumed it to be due to loose props.
Taking the Quadcopter back to the workbench, the issue persisted, even without the props.

I know this sounds like a basic case of bad bearings, but whats weird about the whole thing is, that the noises only occures while using yaw/pitch/roll.
I gave the motors full throttle with no weird noises whatsoever. Furthermore the noises seem to be the loudest with a low throttle value or a higher yaw/pitch/roll (although maybe due to the higher base noise of the motors).

I'm uncertain wether this is normal (which I stronly doubt) or due to a fault on my side. If the latter is the case, what exactly could I've done wrong?
I am using the Speedybee F405 V3 flight stack with Emax Eco II 1700kv motors on a 6S battery.

I am new to this forum and to fpv in general so please forgive any stupid questions or missed details. Please feel free to request additional information.
In any case, thanks for your help (:.

Video with audio would help us to potentially diagnose the issue.

(05-Sep-2023, 09:11 PM)Lemonyleprosy Wrote: Video with audio would help us to potentially diagnose the issue.

Yea sure:




I believe that the noise has gotten better after I resolderd the connections between the motors and the esc (of which I did a terrible job btw)
It could be my imagination combined with my wishfull thinkting though.

That sounds like either bad bearings or way too high d-gains.

Don't think it'd be bearings since they sound fine when you are throttling up and down, definitely sounds similar to what I was experiencing when my d gains were too high as the user above mentioned.

What version of betaflight are you running, and is it the stock tune?

Do not fly it again until you’ve sorted it out, other than very short test flights- you’re likely to destroy a motor, and that motor might take an esc out on its way.

(05-Sep-2023, 10:40 PM)Trip Wrote: Don't think it'd be bearings since they sound fine when you are throttling up and down, definitely sounds similar to what I was experiencing when my d gains were too high as the user above mentioned.

What version of betaflight are you running, and is it the stock tune?

I am using Betaflight 4.4.2. with the stock tune. Even after lowering the D-Gains down to 0.3, the issue still occures.

your stack isnt secured at all, thats a "freemount" not a softmount :-) you cant check it thatway, the sort of softmounting could be the issue, it needs to be softmounted like in use to figure out the issue.

it sounds like a software issue, a signal issue/filter tune/ esc settings from the describtion to me.
a partial broken, diyng esc can sound like that or an esc which has an imossible task.

turn off airmode feature as a try, if it improves it, it would be a sign for a noise issue or high i-term value.
turn of d-min feature for sure on that issue; move the slider for dmin feature to zero. personal i doesnt use d-min feature regular.

(06-Sep-2023, 10:32 AM)hugnosed_bat Wrote: your stack isnt secured at all, thats a "freemount" not a softmount :-) you cant check it thatway, the sort of softmounting could be the issue, it needs to be softmounted like in use to figure out the issue.

it sounds like a software issue, a signal issue/filter tune/ esc settings from the describtion to me.
a partial broken, diyng esc can sound like that or an esc which has an imossible task.

turn off airmode feature as a try, if it improves it, it would be a sign for a noise issue or high i-term value.
turn of d-min feature for sure on that issue; move the slider for dmin feature to zero. personal i doesnt use d-min feature regular.

I know that I should mount the stack properly to the frame, but could that have such an impact?
Turning off airmode did nothing to the noise and I was sadly unable to find the d-min feature to turn off. Again, I haven't tuned the quadcopter in any way.

I tried to use turtle mode with the ESC stop feature enabled, so the motors would not move if not explicitly told so, with the result of **no** scratching noises.
Now I am just confused, because the noise seems to only appear when doing low throttle, slow turning moves with all four motors.

My guess would also be a partially broken esc (but I hope not).

Could the issue be caused by an improper soldering job, mayble because the capacitor isnt attached properly?

Edit: I would like to make sure that it is indeed caused by the ESC before buying a replacement one.

yess, mounting of the fc is very essentialy. there cant come useable signal, we need the best precision for the best result.

one of the main things betaflight does, is sortout the usable gyro signals.

it could be bad mounting only which causes the esc to do such wrong work, causing that sound.


as there isnt susch a sound in the configurator, its a sugn for a well working esc. i actual believe ita not the esc


to disable d-min fearure by slider, you need to turn on "expert mode" on the top to the right

(06-Sep-2023, 08:33 PM)hugnosed_bat Wrote: yess, mounting of the fc is very essentialy. there cant come useable signal, we need the best precision for the best result.

one of the main things betaflight does, is sortout the usable gyro signals.

it could be bad mounting only which causes the esc to do such wrong work, causing that sound.


as there isnt susch a sound in the configurator, its a sugn for a well working esc. i actual believe ita not the esc


to disable d-min fearure by slider, you need to turn on "expert mode" on the top to the right

Alright, so I'll just put some screws on top of the fc? That reminds me, I had to shorten the rubber standoffs of the stack in order to fit it into the frame. But it doesn't make a difference, even when increaseing the spacing.

I've turned the D Gains (Damping) down to 0 (if thats what is meant with d-min) and it makes no difference either.

i would suggest to leave d-min disabled.

as you have powerfull motors, i would suggest to decrease the pids by the multiplier. about 20d 30p 60i.
that shouldnt be to high for sure, than proceed with troubleshooting.

you are using bidirectional dshot, i would give it a try without.

another try could be decreasing the startup/rampup power.
go for 30%, increase it aslong as you dont get that sound.
if you still get that noise, i would suggest to set 40%startuppower - that will be more save for proceed in troubleshooting. it could cause a littlebit less power by the motors inflight.

i saw there is a capacitator, isnt it connected properly?

I'll try that. But since the issue only realy occurs when i **dont** ramp up, but move the sticks only a little I doubt it'll help. The motors make no noise when i push the sticks through.

For the capacitor, i soldert the one which came with the flight stack. I'm not sure if its making a proper connection though. I would expect the fc to be powerd a tynitiny moment after unplugging the battery but instead it turns off the very instant i disconnect the battery.
Its propably nothing though.

(06-Sep-2023, 09:12 PM)hugnosed_bat Wrote: i would suggest to leave d-min disabled.

as you have powerfull motors, i would suggest to decrease the pids by the multiplier. about 20d 30p 60i.
that shouldnt be to high for sure, than proceed with troubleshooting.

you are using bidirectional dshot, i would give it a try without.

another try could be decreasing the startup/rampup power.
go for 30%, increase it aslong as you dont get that sound.
if you still get that noise, i would suggest to set 40%startuppower - that will be more save for proceed in troubleshooting. it could cause a littlebit less power by the motors inflight.

i saw there is a capacitator, isnt it connected properly?

Didn't work either. Actually seems to be worse with smaller starup power. I'll try to resolder some connections and come back to you.