Spirit System

Today i updated to 4.0.1.
My heli TREX800 flies great except for 1 thing.
In fast forward flight the helicopter automatically levels itself horizontally and of course after that it starts gaining altitude because of the pitch.
It has never been like that before. The nose would always stay down by itself but now i have to adjust it constantly otherwise the heli levels itself.

Why is this? Anybody else experiencing this also?

Could use some advice on this too.

The more collective you use the more pronounced the effect is, once you lower collective you'll see it stabilize. You can try increasing pitchup compensation. On ilGoblin Pro I needed to use 3 to stop it going up by itself in fast forward flight (default is 1). With higher value it held better, but I don't know if it's causing other adverse effects or if there is a better way to tune this out.

I still have some issues after releasing collective at high speed (like coming out of an inside out power loop going into forward flight), where it will want to porpoise for a bit but then it stabilizes, it feels weird. Seems integral related but I'm not sure what to change, maybe swashplate integral/dampening need to be tuned? Tuning guide has nothing on this yet.

On previous version I could do a high speed approach and then drop collective, pitch back and do a hard wall stop without anything feeling off but v4 feels less controllable at high speeds.

Pitchup compensation has always been set to 1 and there never has been a problem why would i need to adjust the setting now?

Hello,

this problem could be due to too high Swashplate - Dampening parameter value.
Default is 10 which should not cause the problem. But if you set it too high, then mentioned problem could happen.
Maybe you were trying this parameter or loading old settings from a file which could change the value to a wrong from default.
Can you check this?

Pitchup Compensation can be left at 1.

The value was at 10, i have not touched it so that is not the problem.
I was planning to set pitchup compensation to 3 and test today but if you say it can remain at 1 i don't know what to do anymore. Maybe revert back to 4.0.0.

In that case you can try to set Swashplate - Dampening to 0.

I reverted back to 4.0.0 and tested and the issue was not there with that version. Swashplate dampening was at default, 10. Pitchup compensation at 1.
So your suggestion to put swashplate dampening at 0 for the new version 4.0.1 does not make sense to me.
Why does it need to be 0 to correct the issue if with previous version it flies oke with value 10? I think the problem is something else.

Hello,

all the firmwares you were trying are working in a very different way. For this reason you might need a different settings.
Normally the issue you can observe shouldn't be there, but as I posted in previous reply. You might need to set it to 0 to hide real reason why it is happening. To achieve similar behavior as with previous firmwares.
Although parameter name is same it works differently (see the ChangeLog).
It is unfortunately not possible to set settings that will work well out of the box for all helicopters. For this reason the parameters are available.

Oke i updated the firmware to 4.0.1 again. I set the value for Swashplate dampening to 0.

Guess what? The issue is exactly the same!

This setting makes absolutely zero difference.
But this time i monitored the heli behavior closely and it turns out that when flying forward the heli not only levels itself but it keeps on tilting backwards. So eventually the nose goes up all the way. It is like someone is pulling back the elevator very slightly but it is not me doing it.

So now what can i do because it looks like firmware 4.0.1 is useless for me at this moment.

You can always share your settings for not only guessing. Then we can find more.
In any case 800 class helicopter might need Pitchup Comp at 3 - 4.
Also there are another things to check - whether servos are at the center (servo arms and ° between main blades) when clicking at the Subtrim (tuning).