Good evening! It's my first time using Spirit 2 FBL in my goblin fireball. Heli is stable in hover or when changing attitude/collective but there is a significant roll when you yaw. What parameter should I change? Thanks!

The problem could happen because of:
a) Unit is not mounted perfectly level and is not aligned to all axes.
b) Tail hub is not well assembled causing upwards/downwards thrust which could look like roll during pirouette.
c) Main settings are not correct, causing whole system to work incorrectly. First you should verify that Diagnostic tab is showing channel bars correctly - in right direction, especially collective pitch, aileron and elevator.

Please let me know if it is helpful and you found something there.

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Spirit System developer

Thanks for your suggestions but I don´t think the problem is in built or in the basic setup:

a) The FBL is placed on the suggested spot by manufacturer (Horizontal 0°) and it has 90° to all axes. When in stabilisation mode it hovers perfectly level until you yaw. If placed wrong it would be "running away" I guess.
b) I checked the tail and all seems correct. The heli was flown before with another FBL unit with no problems.
c) Diagnostic tab as well as the servo movement is OK, I can fly the helicopter normally in all modes, the pitch/roll starts only when yawing.

Update: I suspect that high vibration coming from tail might be causing it. It´s my first time flying direct drive heli but I noticed it´s not as smooth as I remember my previous helicopters. I mounted the FBL by provided m3 tape. Today I almost crashed it because of sudden tail wag that was increasing it´s magnitude (probably coused by wind gust). I was flying in stabilisation mode setup by using negative gyro value. Its setup to be -45% which seems to be good value because at -40% it was a bit too slow and the tail couldn´t keep position during collective changes. It was 3rd flight with the same setup and until now the tail helt position nicely. Today a sudden wind gust started strong and very fast tail wig (tail was moving +- 30° left and right). I don´t believe it was caused by high gyro gain as it was flying well until now and the value of -45% doesn´t seem high either.

High Vibrations are usually not causing such oscillations. Rather it could be because of high Pirouette Consistency value. You could try to lower it by 20 - 50.

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Spirit System developer