Translations:Manuals:AR7210FblV5:Quicktrim/7/en
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 with the transmitter‘s AttitudeControl channel and make sure the tail gyro is in Heading Lock mode. 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 color of the Status-LED gives you an approximate indication of how much you did trim and when the trim has changed the Status LED will flash for a moment.
When you place the helicopter in horizontal position and you should be able to see the effect of trimming. When the swashplate is perpendicular to the main shaft this will by the approximate position of the helicopter in flight. 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 by default the system has a trim of 4 degrees to the right to make the heli tilt against the rotor torque (using a helicopter with clockwise turning rotor). Also note that AttitudeControl can not recognize the absolute position of the helicopter. Depending on wind and environmental conditions it may happen that the helicopter stays level but drifts into a certain direction during hovering flight. You may use the trim to compensate this an hang the helicopter more into the wind, but when turning the heli by 180 degrees it will drift even more! So ideally you trim the horizon on a calm day when there is no wind.
As a last note please be aware that this is not a professional autopilot system. The system can be influenced badly by long-lasting vibrations or fluctuations in temperature. As a result it can't be guaranteed that the helicopter does always comply exactly the same attitude. The performance highly depends on many environmental conditions. So keep the system as far away as possible from rotating parts on the heli. Make sure the heli is running smooth and free of vibrations and make sure the AR7210BX receiver is perfectly aligned to the rotation axis of the helicopter (otherwise the axis will be cross connected together and the calculation of the artificial horizon will not match the real movement of the heli).