I am configuring an ASW 28 motor glider with FC Matek H743 Wing V3 with Ardupilot 4.5.2. In manual mode it rolls to the left. Is it possible/useful, using the “flight modes” menu of the radio control. trim the control surfaces? Specifically using two trim configurations, one for manual mode and one for all other modes.
Thanks
Walter
No, do not use RC trims at all, keep them all neutral.
Tune the trims in the SERVOx_TRIM parameters instead.
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Hi Walter,
It sounds like you are one of those pilots who learned to fly manually from scratch 
If you first want to fly the aircraft manually (as usual without FC) the following procedure is better than 2 configurations:
Setting the aircraft trims to your requirements in manual mode by trimming the transmitter. Once you are satisfied with the settings, on the ground read out (mission planner) these PWM values of the servo outputs in the center position, including the transmitter trim, and enter these values as SERVOx_TRIM, then remove the trims from the transmitter.
Rolf
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Or fly with SERVO_AUTO_TRIM,1 and let the FC do all the work.
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Can we introduce differential ailerons to autotrim?
I think auto_trim doesn’t care whether ailerons are differentiated or not, as it only changes SERVOx_TRIM, but not SERVOx_MIN/MAX.
I don’t use SERVO_AUTO_TRIM, it’s better to use manual configuration using the
RCx_OPTION,155 set roll pitch and yaw trim to current servo and RC TRIM RC/SERVO Save.
After manual trimming, you need to switch the switch, usually I use the coach switch and the plane will fly straight. SERVO_AUTO_TRIM and Manual Flight Mode - #12 by egunak95
As long as final endpoints are within ±20% range and it won’t be linear to each side so dropping aileron will be more severely trimmed than the rising one.
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I don’t think that makes a noticeable difference if the airplane has been designed and built properly, i.e. CG and tailplane incidence angle are correct and the control surfaces / elevator are in line with the stabilizer/wings.
No matter which method I use for trimming, after trim flight I check the trim settings visually on the ground and on the mission planner to make sure they don’t deviate too far from 1500 µs or are not good faiered with the stabilizer.
Rolf
In this case it made a quite significant difference
Dashed lines are the result of autotrim’s work.
Green is right aileron (up is up)
Red is left aileron (down is up).
In this case there is quite a lot of difference between left and right aileron.
IMHO trim should be handled before the servo mixer not inside.
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To help you understand: y-axis is servo output, what is plotted on the x-axis and to what scale ?
Command range in % though scale wasn’t captured, right endpoint is max roll right and the left endpoint is max roll left.