I've just replaced an old FC with a new Mamba MK4 F722 Mini with BMI270 gyro running Betaflight 4.3. I've got everything working and the quad does fly but it has an annoying behavior, it slowly rotates counter clockwise about 3 degrees per second without yaw stick input. I can't get it to stop doing this. It's annoying to have to correct with yaw input all of the time. Does anyone have any tips? What I know and have tested:

I've calibrated the radio (Tango 2) even though I'm sure this is not the issue, other quads used with this radio have never had this problem. In Betaflight receiver tab the yaw axis is dead still when the radio is on.

In Betaflight setup tab (where you can move the quad and see it in Betaflight) it does rotate counter clockwise but at an extremely slow rate, about 30 to 40 seconds for 1 degree. When flying the quad rotates much faster than that, roughly estimated to about 3 degrees per second.

Throttle does not seem to have any effect on rotate speed, at least not that I have noticed.

I'm new to filter settings. I did try changing some filter settings without really knowing what I was doing but nothing really made any difference. Yaw low pass filter sounded interesting but changing values here and there didn't do much but I only tried random changes.

Any tips? Do I need to start taking blackbox logs and learn how to read them?

edit : check 3 first

2 thing you can try (had the same problem on a few own build quads and either 1 or 2 or a combination solved this yaw auto rotation.)
1. check your pid for yaw and look at I term. Increase it. Like double for example. Same for feedforward.
Should be zero D term (not used on yaw) , dont touch P ( set sliders to RP instead of RPY to release the yaw numbers)
2. if you have blackbox logs its an easy spot on the accelarator, but make sure your fc is properly soft mounted and isolated from any vibration as much as you can. If you fly acro then this is less of an issue as does not use accelerometer.

also 3
as you mention it even rotates in BF check if you have set some deadband, like 3 to 5 or so on yaw in receivr tab in Bf. If you Tango gimbal signals flutter a bit this could create a small input if you have no deadband. I have mine set to 5 eventhough the values when not touching the tango flutter by +-1 max.

a deadzone could help or just trim by the radioand maybe correct rx range via cli

check the board aligement, maybe correct it there

as you told there is a difference inflight and on bfc, that sounds like hardware to me. i would check for any short, screw on the windings? solderball? loosen capacitator? to much force on the board? this direction

Is the stick centered count for yaw on the receiver page 1500? Set SubTrim to get it so?

Thanks for the suggestions. I've now set some deadband on the receiver and also increased those values for YAW in PID tuning page. I'll do a test flight tomorrow and also record blackbox data. If it still rotates I'll have to look at the mechanical stuff. The rotation I'm seeing is very constant, the rotation speed does not appear to change at all. It's a very tight build and the battery strap under the Air Unit could be pressing on the FC. If nothing else works I'll remove the Air Unit to see if pressure on the FC is causing this.

The FC orientation is fine, it does fly and I can control it, it's just that it rotates a little. It is soft mounted, but noob as I am I have no idea how tight I have to screw on the nuts. If I remove the Air Unit and it still rotates I'll loosen up the nuts a little and put some more spacers between FC and ESC.

(15-Dec-2022, 10:25 PM)BadRaven Wrote: Is the stick centered count for yaw on the receiver page 1500?  Set SubTrim to get it so?

How do I set SubTrim? It's not something I know anything about (I'm a noob). Stick is centered, sometimes hovers to 1501 but that's a lot slower than rotation in real flight. I don't know about SubTrim though. Is that done in Betaflight? I don't want to change anything on the radio as the other quads I fly with it do not behave this way, they are fine so I don't want to mess about with changing values on the Tango 2.

If these don't work, you might check to see how tightly the flight controller is mounted. I once cranked down the nuts on mine without knowing any better, and ended up causing some roll drift. Enabling angle mode or return to home would cause the quad to pick a random orientation (often upside down) and I'd constantly need to adjust in acro.

(15-Dec-2022, 09:39 PM)fpvapnea Wrote: edit : check 3 first

2 thing you can try (had the same problem on a few own build quads and either 1 or 2 or a combination solved this yaw auto rotation.)
1. check your pid for yaw and look at I term. Increase it. Like double for example. Same for feedforward.
Should be zero D term (not used on yaw) , dont touch P ( set sliders to RP instead of RPY to release the yaw numbers)
2. if you have blackbox logs its an easy spot on the accelarator, but make sure your fc is properly soft mounted and isolated from any vibration as much as you can. If you fly acro then this is less of an issue as does not use accelerometer.

also 3
as you mention it even rotates in BF check if you have set some deadband, like 3 to 5 or so on yaw in receivr tab in Bf. If you Tango gimbal signals flutter a bit this could create a small input if you have no deadband. I have mine set to 5 eventhough the values when not touching the tango flutter by +-1 max.

I followed your steps 1 and 3 and also enabled the yaw low pass filter at 70Hz according to some recommendation I find somewhere online, and it rotates no more! So thanks for your suggestions. I will back up this configuration and then slowly go back to default to find out if it was one specific change or a combination, I do want to learn about this stuff.

Well, I did say I wanted to learn this stuff... and now I did learn something... When making backups of everything I saw these lines in the dump:

###WARNING: NO CUSTOM DEFAULTS FOUND###
###ERROR IN dump: NO CONFIG FOUND###

Although fpvapnea's suggestions did solve the issue of rotating I thought that flashing again and applying those custom defaults was worth doing anyway so I flashed with full erase updating from 4.3 to 4.3.2, applied the custom defaults and did the basic setup. Whatta ya know, it does not rotate. I guess this is elementary stuff for most but noob as I am I assumed the FC would be flashed with the custom defaults from the manufacturer. I now learned that this assumption was wrong.

I’m still a noob an learn new stuff here every day.. I have read in other threads “no custom defaults” when going to the latest BF firmware… someone posted something regarding flies to add in the cli after from the GitHub page or they were hex files..

Custom defaults are the Betaflight target defaults for a specific FC, not the manufacturer defaults for a specific BNF that an FC is installed in.

If you get the "###WARNING: NO CUSTOM DEFAULTS FOUND###" message in a dump file for a BNF quad it means that the manufacturer was lazy when flashing Betaflight to the FC and they simply just flashed the base STM target file (as opposed to a specific board target) such as STM32F405, STM32F411, STMF745, STMF7X2 etc. depending on what MCU the FC uses after which they then just manually applied their own dump settings. This is a dangerous scenario because it means if you do a "Reset" of the FC from the Betaflight Configurator GUI or you run the "defaults" command in the CLI you end up with completely vanilla Betaflight settings for the particular MCH with NONE of the resources mapped to anything.

The way to get rid of the "###WARNING: NO CUSTOM DEFAULTS FOUND###" message is to flash the correct Betaflight target for the FC, then click on the "Apply Custom Defaults" when prompted (during first connection to the FC after flashing firmware), and then apply the manufacturer config for your specific BNF over the top of the Betaflight defaults which will then correctly remap any resources, configure the ports, configure the ESC settings, configure the modes, configure the PIDs and filters, plus anything else including FC / gyro orientation that is specific to that particular BNF quad.

Dont beat your head about it Mike C. This is part of the learning. If everything always works , you will be bored fast with this hobby hahaha.
Something goes wrong or does something you dont understand , you investigate , you learn , you fix , rinse and repeat. And before you know it you will be an expert.
Dont be afraid to experiment (at least with small quads as with a big boy experimenting a bit too much can turn your cat into sushi, but you get the point.)
Make lots of backups so later you can compare what you did and what changed.
And of course "Have fun"

(16-Dec-2022, 05:28 PM)fpvapnea Wrote: Dont beat your head about it Mike C. This is part of the learning. If everything always works , you will be bored fast with this hobby hahaha.

I find the troubleshooting, building, and repairing part of this hobby just as much fun as the flying!  Maybe that's why I'm okay with pushing my limits...  means I can repair rather than spending money on new parts to build something else all over again.

(16-Dec-2022, 04:20 PM)SnowLeopardFPV Wrote: The way to get rid of the "###WARNING: NO CUSTOM DEFAULTS FOUND###" message is to flash the correct Betaflight target for the FC, then click on the "Apply Custom Defaults" when prompted (during first connection to the FC after flashing firmware), and then apply the manufacturer config for your specific BNF over the top of the Betaflight defaults which will then correctly remap any resources, configure the ports, configure the ESC settings, configure the modes, configure the PIDs and filters, plus anything else including FC / gyro orientation that is specific to that particular BNF quad.

I flashed with target and Betaflight configurator asked me to add custom defaults which I did. I still had to set some stuff up but once I did that it could hover without rotating. Tomorrow I'll take it for a little spin and see how it behaves.

(16-Dec-2022, 05:28 PM)fpvapnea Wrote: Dont beat your head about it Mike C. This is part of the learning. If everything always works , you will be bored fast with this hobby hahaha.
Something goes wrong or does something you dont understand , you investigate , you learn , you fix , rinse and repeat. And before you know it you will be an expert.
Dont be afraid to experiment (at least with small quads as with a big boy experimenting a bit too much can turn your cat into sushi, but you get the point.)
Make lots of backups so later you can compare what you did and what changed.
And of course "Have fun"

Haha, no worries on beating my self up, ain't doing that at all! Now I know not to assume a manufacturer will flash a FC with everything just because they might when they sell pre-built quads. No worries with experimenting, I got this quad with a DJI Air Unit for a price lower than what an Air Unit costs, I've bashed this one up pretty bad. It's on it's second frame and now second FC. I'm much more cautious with my GEPRC croc5 which I bought brand new. You could say I bought this one to learn... instead of learning by building a quad from scratch I learn by bashing it up when learning my own piloting limitations, and then learning to fix stuff when stuff needs to be fixed on it... and learn I do, many thanks to the folks in here!