I just checked and I was wrong; it weighs 665g with the 3S battery included. I checked the thrust tables and I think I’m okay. It might be an old battery that is causing me issues.
Alas there is no current measurement with the F405-STD (one of a few reasons why I wouldn’t recommend this FC…). I did do a hover test and measured the battery capacity difference using my charger; average power was 260W and average current was 21.6A with 3S.
Flight from today with these settings. Autotune failed (although it was a bit windy). It felt a bit more stable.
Log: https://www.dropbox.com/s/z6ulsxo53cephww/2023-01-02%2012-32-09.bin?dl=0
Video clip: https://www.dropbox.com/s/awkrb4k3hpe55ps/VID_20230102_123713.mkv?dl=0
Thanks.
Hover current should be more like 12A. Anyway, why don’t you replace the battery before continuing with tuning. An average commanded output of 1750us at Hover is not worth spending tune time on.
I would guess that if you do some aggressive flying the motor outputs will max out, and stability is lost then, and perhaps some thrust loss errors.
At 665g you are now over 50% throttle at hover. You will find most craft in this size range on the forum here are in the 30-40% range. All of mine are.
I bought a 4S battery at last and did a side by side comparison. Subjectively the 3S feels more stable than the 4S. :-S
This is the 3S log:
https://www.dropbox.com/s/48vaa75rdsznk89/3S.bin?dl=0
Then I swapped the battery for 4S immediately after:
https://www.dropbox.com/s/y9f43zoadlp4jkm/4S.bin?dl=0
I plotted 3S RCOUT:
And 4S RCOUT:
4S throttle is on average about 100 less than 3S but in my amateur view, the problem seems to be a motor power discrepancy. The motors cosmetically are identical but in reality one needs much more throttle to fly. What do you think?
It’s showing a large mechanical Yaw bias. Not sure how that can happen with that frame. Are the props in good shape?
What is the take-off weight now? And for further testing of this just hover in Loiter or AltHold.
Take off weight has not changed significantly as the 4S battery is very close to the same weight as before.
I checked the props and they all appear undamaged and are from the same batch.
Motors are cosmetically identical but I can’t help thinking one is perhaps internally damaged? Or could the ESC be in poor shape?
I shall do a hover when I next get a chance. Thanks.
Check for arm/motor mount twist.
All arms are rigid and motors too. The arms are short carbon fibre ones. At this stage I think it must be an ESC issue.
That would be quite the coincidence that the CW motor ESC’s are different than the CCW motor ESC’s. But you are using PWM so try a ESC calibration anyway.
I did a calibration and it did help because now I think about it, the motors had a habit of having different minimum spin voltages.
I then did a hover test at 3S:
and 4S:
Still wobbles more at 4S and wobbles a bit at 3S. I think I have to give up. There is clearly a motor/ESC issue at play and I probably should replace all ESCs and motors with known good ones to get rid of the problem. :-/
