Why does this happen?

[CapedVulture]

Hi all

I have a generic question that I've noticed with all my models (Trex 550, Gaui X5, Trex 700L Dominator) and all models having different flybarless units (3GX, mini Vbar, GPro).

1: When doing high speed hurricanes and putting the model under a lot of "G" load, the tail will eventually spin out. It does not hold?
2: When doing piro flips or piro funnels with right rudder, as soon as you increase the "G" load, the tail does not rotate as freely? Sometimes the rotation stops, unless you reduce the "G" load?

Same manuvres with left rudder is NOT a problem? This, I'm guessing is due to natural torque effect of clockwise rotating main blades. The tail naturally moves left.

I see it's an issue with all models and regardless of Flybarless unit.
I'm just curious if anyone else has this issue and what they have done about it?

I've tried turning up tail gain etc
The GPro Domiator 700 seems to behave the best and the tail holds well, most the time.

Any thoughts, comments welcome.

[RC/DC_5000]

You didn't mention the Rudder I and Rudder P gains in the Gpro software. You should read more about these and turn them up as high as possible, just before unwanted movement (oscillation or otherwise).

VBar also has these gains. But they greatly affect the holding strength of the tail and the overall affect of the tail gyro.

The tail will not blow out if you get all these gains adjusted correctly. For your blowouts, you need to look specifically at the Rudder I gain.

But yes you're right, the directional yaw hold is different because one direction has all the anti torque from the main blades. So that direction is very sensitive and takes time to tune.

[rhodesengr]

I am guessing you are simply running out of tail range. The FBL controller will move to tail in accordance with what you are asking the heli to do. If the tail hits the limit (set in software), there is no more tail range available so you see blow out. No amount of fiddling with gains will increase the available tail range. The tail range of pitch is set by the geometry of the tail. The eoffset suggested for example in the Align instructions simply puts the servo arm closer to center when you are hovering. It does not change the actual range.

If the blowouts are caused by hitting a tail limit, the only solution is to increase tail authority by either increasing the tail speed relative to the main, using longer tail blades, or stretching the boom. Any of those will reduce the amount of tail pitch need for a given amount of thrust so your effective tail control range is increased.