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Tips to get symetrical movements for control surfaces.

So I built my second plane which is a 22" slofly. I noticed the rudder does not move symmetrically meaning that it moves further to one side then the other, or it will turn harder in the air one direction versus the other (if using the rudder to turn). I was curious as to what tips/tricks you can do to avoid this situation so I know what to do in future builds.


New member
you are working with whats called differential. it happens when the holes of your control horn are not directly over the hinge line. on future builds, if you get those holes directly over the hinge line you should be good :)
Have the servo centered as best you can and then install the servo so the arm is parallel to the control horn. The servo may have to go in crooked to get it straight. I have done this many times as some servos don't line up exactly in the center.

Ak Flyer

Fly the wings off
Power up the servo, center the trim and then put the horn on at 90 degrees. This will assure you even travel on that end. Install your control horn so at mid travel the holes in the horn should be over the hinge point. If you have that set, your control surface should always have the same throw. You can then adjust servo travel and linkage length to get longer or shorter throws but they should remain even. If you have programming in your radio, make sure your travel adjust is even to start with and your servo sub trim is centered.