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Helicopter 4.0.5 tune HELP! :(

What type of autopilot do you use ?
Could you attach some pictures of your installations ?

Yes, I understood… but in logs appears a red tags “gps 2 error” that in my opinion are incorrect indications.
Anyway I tried the settings suggestid from Bill. The helicopter is more stable but the ekf failure (velocity and Position) are still present.
I’m using the phixhawk 3dr Px4 , with a Taoglass LEA6 V1.2 3dr gps+compass.
I’ll send you the new logs and pictures soon.
Thanks for the help.

Hello @bnsgeyer,
hello Bill,

I am new here in the community and I am from Germany. And I have a rusty English. And I am new with flight controllers. I only know the FBL systems like Bavarian Demons …

I became aware of this forum through Holger Schutz (a German author for a German model helicopter magazine). Maybe you know Holger.

I followed this thread, because I have started configering a Pixhawk 4 Mini (with GPS and telemetry) on a TREX 600 EP. Because of our bad weather here in Germany I could not make a test flight untill now.

For the configuration, I followed the pages for the traditional helicopters. And I adopted the suggested parameters from the “Advanced Tuning for trad. helicopters” (
But, some of this parameters differ from the paramteres you suggested for the setup of Avro93.
Would this changes be good at all or only for Avro93s setup?

It would be very nice if there were a list of important parameters for different sizes of helicopters with which one could safely start without making a serious mistake. Then you can fine-tune.

Are there such lists? Maybe I’m too demanding as a newbie to the forum. Please excuse.



@heri Welcome and thanks for posting. Yes I have worked with Holger a lot over the past year or so. The changes I suggest for Avro93 would be good for all users which are listed below
These will improve the flight characteristics of the aircraft. You do need to tune ATC_RAT_RLL_VFF and ATC_RAT_PIT_VFF according to the wiki to further improve the flight characteristics.

Let me know how it goes.


@bnsgeyer Hello Bill,

thank you for your fast reply.

I will change the parameters as you suggested. And I will let you know about the results.

Do Holger have an account in this community? In two of his articles in the modell helicopter magazine he named your name and that he got a lot of help from you.
Although I’m in the German Scale Helicopter Community myself, I haven’t spoken to Holger personally yet.



Here he is. Problem Mission Planner App mobile phone

@FRED_GOEDDERT Hello Fred, thank you. Yes I found him just some reading posts later :wink: . Seeing your name, could it be, that you are German too?



I am a New Zealand citizen. Yes German background. ( 70plus old)

Hello Bill,
for my new report in the German ROTOR newspaper I have rebuilt one of my helicopters, with the values from the wiki. However, I took your new values (for Avro93).
It flies well and is suitable for beginners.
However, these 4 values are set to “0” in the wiki.
What is better, what should I write?
Will this be changed in the wiki?
What happens if I change VFF?

I am in contact with HERI.

Many greetings Holger

Translated with (free version)

I would recommend using the values I provided to Avro93 which are listed below

Yes it is important to tune this parameter. I hope to have heli autotune out for initial testing soon. This first version of autotune will tune VFF and ANG_P which should help a lot of users.

hi, thank you!

Autotune for Heli will be great…



Last Sunday was a 2 hour break from the storm and rain. Whereby the wind was still at 2 to 3 wind strengths and very cold. So far too much to do a tuning flight. But it was good enough for a first hop.

I had taken the values ​​from the tuning pages and the improvements made by Bill.

I only set the value for ATC_RAT_YAW_VFF to 0.035, as I fly my TREX600 with relatively low rotor head speed. I am a Sclae Heli pilot, so I am used to fly with low rotor head speed.

So I started to the first hop: As the heli got lighter I noticed that the tail rotor wanted to turn the helicopter and the helicopter wanted to tilt to the right.

I took my heart and soul and increased the pitch to the hover angle pretty quickly. The helicopter jumped into the air and then stood floating quite calmly. Judging by the weather conditions.

At the beginning I noticed a slight shaking, which I could primarily observe on the landing gear skids. I think the tail rotor swung back and forth at a high frequency. Over time this got better but wasn’t entirely gone. It may be that I changed the value for ATC_RAT_YAW_VFF too much. I have now set this to 0.024. And now, I wait for the next flight. So the weather cooperates.

I also tried at evaluating the log files for the first time.
Here I wanted to look at the VIBE parameters.

Here is a question right away: Which level do the X, Y and Z axes mean in the traditional helicopter? Probably a stupid question, some experts will ask.



I found the ROTOR magazine online. I looked up the article you wrote on your experience with ardupilot last May. I ordered a copy. I look forward to reading it. Good thing I have google translate :slight_smile:


I also saw on the cover a scale model of a U.S. Naval Test Pilot School TH-6B. What a coincidence.


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hi Bill,
very good!
meanwhile I have a fligthcontroller in 5 Helis: 3 x tandem, 1 x scale, 1 x 500er.
All are flying good.

When do You think You have the first Heli-autotune for testing?


I hope to have it ready by the end of this weekend, if the weather allows me to do some testing. This would be higher risk testing as I will have only tested it in SITL and on my heli. I have attempted to make it so that you can always switch out of autotune and return the settings back to the original settings. I have put my autotune changes in the stable release (4.0.6) to minimize some risk of testing with Master. I will post on this forum that I am ready for initial testing and provide firmware to those that are willing to test it.

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Hi Bill, thank you for your work you are doing for us all!

Autotune would be realy fine to have.

I myself, i am not good enough yet for testing.



hi Bill,
great -I would try it



Yesterday the weather was good and I tried an other test with my TREX600/Pixhawk.
I reduced the ATC_RAT_YAW_VFF to 0.024.

The first testflight was good, but I think the tail still swings a little bit. So I changed ATC_ANG_YAW_P to 4.3 . In this test I just hovered around a little bit.

Second flight. Everything went right. I tried AltHold: Ok, no big jump when switching.
I tried Loiter: Ok. I switched between Loiter, AltHold and Stabilize for a few times.
Everything normal.

I tried a bigger circles, about 50 meteres, all in Loiter Mode.
Suddenly the helicopter jerked around, as if one were giving roll and pitch commands briefly but strongly. The whole thing took maybe a second or two. Then everything was normal again. As far as I could tell. Since yesterday I have been busy with the data flash log file for hours. As a beginner in this area, I have a hard time with it.

I think I am having problems with the compass. Could you take a look at the log file. The event was between 14:14 and 14:15 (hh/mm)
Here is the Logfile:!AjSq727ChpJzaTEANaAQG7SZl3U?e=YSRqMi

And here the Parameters:!AjSq727ChpJzai5haUrUh3ameb8?e=KDz3Q2

Would be very kind if somebody could help me.

When I installed the Pixhawk, I took the installation location of the previous FBL system. But that sits directly in front of the engine and above the engine governor. Probably not optimal.

Before I start converting everything, I would like your opinion as to whether the compass is the cause of the malfunction?



Looks like you had “EKF Yaw reset” that initiated all …
compass used had started to flip between 1 and 2

Thank you for your help.

Yes, I saw the Event Message “EKF yaw reset” in the Datalogs too.
Three times, one shortly after the other. And shortly after this you can see an error code “EKF Primary-1”. It all appears around the time where the strange behavior was.

I looked at the NKF4 entries in the log file viewer. I think I can see bad behavior here, but I lack the experience to interpret it correctly.

I looked at my compass values ​​again in the setup. The internal compass is entered here as the first compass. I will recalibrate the compass and put the external compass in the first place.

Nevertheless, I would be grateful for further investigations of the log files by experts.



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