Stable hover but wobbles and falls on large inputs

Hi all,

I have a Pixhawk quad with latest 4.0.3 firmware. It is stable in a hover and I can move it around with gentle inputs but as soon as I give a too large input deflection it starts to wobble and then falls down. Please find link below to log file.

Thanks in advance…

Can you please post a .bin file? the .log doesn’t help

Oops my bad - please see below:

Did you follow the instructions in this wiki?

What flight mode were you in? How big is the copter?

I just reviewed your logs

Seems like there is a ton of oscillations.

Also is this a 3s battery?

Looks like you set a few options from the guide, but missed others.

As was mentioned above… Did you follow the tuning guide?

Can we get a few details about your craft?

Size? Prop Size?

Hi guys,

Yes I did follow the instructions on that page but I’ve only gone as far down as the “Initial Aircraft Tune” section for now and all flights flown were in Stab mode. I used CH6 to tune the Pitch/Roll Rate P values and after it wanted to flip on the first takeoff I lowered it and at around 0.1 it seemed to be flying “stable” and that’s where I left it. Here are my copter specs:

60cm DIY ArduCopter Frame
20-22L Hacker Style 924Kv Brushless Outrunner Motors
HobbyKing HK-HW30A ESCs
GemFan 11x4.7 Props
3s 5300mah Battery
AUW = 1585g

Which options did I miss? I know I still need to work on the battery settings because on this last flight the MP stated 4445mah was consumed but I only put 1910mah back in…

Your esc-s are not for Multicopter, their response is not linear, no surprise you crash on quick movement. Get a right esc.

I have a few Turnigy 18a and 25a ESCs in my spares box. Would those work better?

Unless you change the firmware on them for SimonK or similar, NO.

Okay thanks. I guess I’ll have to shelve this project again then until after the lockdown…

When you get everything set as far as hardware, these are the settings you need to apply


Thanks Dave,

I found some HobbyKing F-20A ESCs on an old quad which I will salvage and flash with SimonK.

1 Like

Quick question. Which firmware will work better these days, SimonK or BLHeli?

Is the SimonK firmware still being updated regularly because I tried looking for it online and the GitHub stuff all seem very old.

I don’t think anyone has heard from Simon Kirby in years and what development there was stopped a long time ago.Today it’s usually associated with the cheapest poor quality ESC’s like what comes in those All-in-one kits. You want either BLHeli_32 or Hobbywing (they make BLHeli_32 ESC’s also) IMO. At the very high voltage/current level there are other choices.

Would trying BLHeli16 on the F-20As be a complete waste of time then? I’ve managed to flash the latest v14.9 on all of them but I still need to solder them back into my quad.

Not at all . If they flashed to BLHeli of any version it’s good.

@Dkemxr Indeed, however the latest BLHeli-Atmel is three years old as well and there is no significant difference between SimonK and BLHeli-Atmel, especially with the ESC’s that André has. Both firmware will do just fine.

1 Like

Yes, I suppose you are right If it’s plain vanilla BLHeli. I have a quad with BLHeli_S firmware ESC’s and passthough works using the right Suite so a small advantage there just for configuration. Well, OK just to reverse the motors if required.

Thanks guys. I will let you know how the next flight went then…

If you are buying ESCs new… I wouldn’t get anything less than BLHeli_32