Parameter menu point A
The first menu point of the Parameter menu gives you the possibility to easily adjust your servo center trim on the flying field as for instance your helicopter does slowly drift in hovering flight or when it doesn’t climb out straight on collective pitch inputs. Additionaly when using the AttitudeControl feature you may trim the reference point for the artificial horizon in case the heli is not leveled correctly.
Never use the trim functions of your remote control! MICROBEAST PLUS will see trim as a control command to turn the heli and not as servo trim.
There is one exception: The rudder servo can be trimmed on the remote control when the tail gyro is operated in Normal-Rate mode. Note, however, that this trimming should only be temporary as MICROBEAST PLUS calibrates the stick center positions during every initialization process. Thus, on the next flight the servo would be back on center position despite trimming in the transmitter.
Contrary to centering every single servo at Setup menu point G, here you are able to directly adjust aileron and elevator without taking care about the single servos. Similar to the digital trim function of most transmitters here at Parameter menu point A you can adjust the swashplate “one click“ by shortly moving the aileron or elevator stick in the desired direction. If you want to trim the swashplate any further repeat tapping the stick several times or simply hold the control stick pushed for a longer time to automatically perform several trim steps. The color of the Status-LED gives you an approximate indication of how much you did trim.
Please note that this function, as opposed to the digital trim of the transmitter, is not a separate trim function. Here you directly adjust the servo centers as well as you would set servo centers at Setup menu point G. Technically there is no difference between Parameter menu point A and Setup menu point G.
If the tail gyro is operated in Normal-Rate mode, the rudder servo must often be trimmed precisely so that the tail rotor produces just enough thrust to counteract the rotor torque in hovering flight. Otherwise the helicopter would constantly drift into one or another direction on its vertical axis as the gyro only dampens sudden movements but does not control the tail rotor‘s absolute position.
To trim the rudder servo proceed as follows: Switch the tail gyro to Normal-Rate mode fly the helicopter. By using the digital trim function of your transmitter trim the rudder servo so that the helicopter does not drift in hovering flight. Land the helicopter and immediately open Parameter menu point A by briefly pressing the button on MICROBEAST PLUS once. To take the tail trim value from the transmitter once again press the button and this time hold it for at least 2 seconds (if you briefly press the button only, you would switch to menu point B!). You can see the rudder servo move to the new center position and the Status-LED will flash for some moment to signalize the position has been set. Now reset the digital trim of your transmitter back to zero.
- MICROBEAST PLUS only accepts the the tail trim value from the transmitter when the gyro is set to Normal-Rate mode. When you land after the trim flight and open Parameter menu point A make sure that you do not change the gyro mode and/or trimming of the transmitter by accident, e.g. when using a flight mode switch in the transmitter.
- If the tail gyro solely is operated in HeadingLock mode, trimming the rudder servo is not required under normal circumstances. Here the gyro actively controls the rate of rotation whereby drifting is excluded on the vertical axis. Anyhow, in unfavorable mechanical conditions it may be helpful to fly the heli in Normal-Rate mode once and to trim the rudder servo accordingly, so that the mechanical throw is balanced more equally.
During the trim procedure you can delete the just performed trimming by moving the rudder stick in any direction. All servos will be moved to the initial position from entering Parameter menu point A. Note that a subsequent reset to previous states is not possible! If the servo trimming was changed and Parameter menu point A is left, the servo positions will be saved permanently. You can only bring back the servos to the previos positions by manually trimming them back into the opposite direction.
The trimming of the rudder servo will be fully deleted when the tail rotor endpoints are readjusted at Setup menu point E!
Trimming the artificial horizon (optional)
If the helicopter is not aligned horizontally as desired with active AttitudeControl, i.e drifts to one side in hovering, the artificial horizon can be readjusted. To do so, activate AttitudeControl at Parameter menu point A via the transmitter‘s AttitudeControl channel to switch from trimming of the servos to trimming of the horizon. The Status-LED will flash indicating that AttitudeControl is on (if the Status-LED is lit permanently, you are in servo trimm mode as described above). By moving the aileron or elevator stick the roll and pitch tilt of the horizon can be increased/decreased. Briefly touching the appropriate stick will trim the horizon stepwise by 0.5 degrees to the specific direction. Touching the stick repeatedly or holding it for longer time will trim the horizon by several steps. The Status-LED indicates the trim values: when it lights in blue color both angles are 0 degrees resp. they are in the factory setting. If the Status-LED lights red, one or both angles are adjusted slightly. If the Status-LED is purple then one axis is trimmed by more than 5.0 degrees. When the Status LED goes out, one of the two axes is further trimmed than 10.0 degrees, which is the limit for each axis! By moving the rudder stick you can remove the trimm that has been set since entering this menu point.
Place the helicopter in horizontal position and you should be able to see the effect of trimming. Note that the helicopter usually is slightly tilted to the side in hovering flight due to the drag of the tail rotor. Therefore as a starting point you may trim about 1-2 degrees to the right when using a helicopter with clockwise turning main rotor to make the heli tilt against the rotor torque, but by default it should not be necessary to use any trimming at all. Note that AttitudeControl can not recognize the absolute position of the helicopter. Depending on wind and environmental conditions it may happen that the helicopter drifts slightly into a certain direction during hovering flight. Also long-lasting vibration or fluctuations in temperature can cause the helicopter not always comply exactly the same attitude. Also make sure the MICROBEAST PLUS unit is perfectly aligned to the rotation axis of the helicopter otherwise you the axis will be cross connected together and the calculation of the artificial horizon will not match the real movement of the heli. Therefore only trim in moderate steps and only when the helicopter reproducible drifts to the same direction otherwise trimming can make the drift even worse!
Push the button to save the configuration and to proceed to Parameter menu point B.