Cross posting this for more visibility from the motor, esc, and prop section. Link


"Alright so I'm hearing a sort of rattling sound when I release the throttle after a quick burst. There's no indication of this in the controls when flying. I only noticed it in the Gopro footage. Think this is anything to be concerned about? 

The video is below and here's my build thread for the parts list: https://intofpv.com/t-i-ve-decided-to-bu...th-machine





Thanks!!

Edit: Most noticeable at the 0:30 mark"

I mean, it certainly doesn’t sound healthy, but I don’t have a mic on any of my builds so I can’t say if it’s abnormal.

If your prop tips flex up or down, is there anything they can hit?

If I recall correctly, you used new motors on this build, so it’s unlikely your bearings are worn out.

I suppose it could be an esc setting, but it certainly sounds mechanical to me. If you grab your bells, can they lift off of the stator at all?

(17-Jul-2023, 08:23 PM)Lemonyleprosy Wrote: I mean, it certainly doesn’t sound healthy, but I don’t have a mic on any of my builds so I can’t say if it’s abnormal.

If your prop tips flex up or down, is there anything they can hit?

If I recall correctly, you used new motors on this build, so it’s unlikely your bearings are worn out.

I suppose it could be an esc setting, but it certainly sounds mechanical to me. If you grab your bells, can they lift off of the stator at all?

Okay so I guess I'm not aware how much props flex in flight. I pulled on them pretty hard though and they come extremely close to the GoPro tpu case, but definitely don't touch it. And there's no marks on the case or prop that would suggest any contact. I will fly as soon as the weather lets me to confirm it isn't the GoPro case.

Yes new motors and I've been pretty tame with the build so far - zero crashes. 


The bells do not move up and down whatsoever. And I can't tighten the prop nuts anymore than they are.

Can you explain how it could be an ESC setting? Hognose mentioned that in the other thread and I'm unaware how that works. Also would bench testing and spooling the motors in Betaflight prove of any use?

Just a quick update...

I plugged into Betaflight and spooled the motors and there is no sign of the sound. Ran them in the ESC Configurator and the same result, no sound. 

Here's a look at my ESC settings:

Nope, I can’t explain.
The “I suppose” was because it sounds plausible to me that an esc setting could cause it, but I don’t have the knowledge to be able to say whether it is or isn’t, or what setting may change it.

In my head, it makes sense that it could potentially be active braking, so I might consider reducing braking strength and see if it makes a difference- but that is a wild guess based on speculation and lack of knowledge, NOT a recommendation.

I still think it sounds mechanical. Something rubbing/hitting/vibrating.

Sorry that’s not super helpful.

I’m inside so I can’t listen to your video again without upsetting my critters- does it happen when throttle is cut regardless of angle of attack? In other words, if you go straight up, then cut the throttle, does it happen? Or does it primarily happen as you cut throttle and pitch back to reduce forward movement?

I dont really have enough video footage to gather the exact data. But it seems like it's when I throttle hard up, then immediately bring it back down to 0 I create the issue. But like if I throttle up and ease off the stick and slowly bring to 0 then it's not happening.

Hoping tomorrow plays nice with weather and all I'll do is take video to collect data and see if I can narrow that down. But I also want to see what happens with the GoPro off and see if I can hear it above me.

Okay so it turns out I was completely wrong lol. It’s not when I raise throttle that it makes the noise it’s at the start of a roll or pitch movement.
I’m now certain it’s not the props hitting anything and it’s not any loose hardware. The noise definitely comes from either the motors or the ESC. Any advice is appreciated even if it’s a guess at this point. I just need something in the positive direction as I don’t want to fly it with the noise.

Here’s the video:


https://www.youtube.com/shorts/j-h2Ve2RlaU

I FIGURED IT OUT!!!

When I built the quad, I used the SupaFly preset tune in Betaflight. When selecting this preset, there's an option to select a receiver and I selected ELRS. Wellllllll, it clearly states that its ELRS at 500hz, however my Boxer is set to 1000hz. This excess non-audible-noise apparently must cause the audible noise I was hearing. 

Set my radio to 500hz and not a sound!