Hi, I have posted two images,
I saw that in advance mode, under throttle&gov have pitch,cyclic,Tail precomp, and on other tap setups1,2,3 under Tail section also have tail precomp, and cyclic. Could you explain what's the difference? And how can I tuning my heli? Which come first, and how much I add or subtract each times?
Also my heli feels like it acting, when I do nose elevator into inverted the tail drag/drift little bit to the left.
Although the names on the two screens are the same, the purpose is different:
In the governor, pre-compensations are used to increase the power while increasing the load on the motor by increasing the pitch so that the power is increased "while" the load is increased and thus "before" the motor slows down. This is to try to keep the RPM of the main rotor (and consequently the tail rotor) constant so that the response speed of the model remains constant.
In the tail, the pre-compensations are used to increase the tail rotor thrust (anti-torque rotor) "while" the main rotor torque is being increased and therefore "before" the tail moves due to the increased main rotor torque.
The default values are usually already fine, but of course these values can be "optimized" for the governor depending on the power that can be delivered by the battery, the ESC and the motor and for the tail depending on the tail reduction ratio that determines the tail RPM, the shape and model of the tail blades and their length.
Regarding the governor the best method is to check with a flight log how the RPM behaves when you increase or decrease the collective pitch of the model (do the RPM decrease and the precompensation is increased or do they increase and the precompensation is decreased?) you will never be able to get a perfectly straight line of RPM because of the various response times but you can check the "trend".
As far as the tail is concerned, you only need to check the behavior of the tail when hovering in full pitch. If the tail tends to rotate in the opposite direction to the main rotor rotation the pre-compensation should be increased otherwise it should be decreased.
But first you should adjust the tail P-gain as best as possible (this can easily be done from the transmitter using the Gyro Gain menu of TX) and then the tail I-gain (this can be done by setting three I-gain values in the three Setups and changing the Setup in flight to see which value is the best).
Finally I would like to say that before doing all these operations it would be better to check that when you change the collective pitch control you do not unintentionally interact with the tail stick control. To check this, simply raise the "tail stick deadband" value (ADVANCED, Setup tab, Input).