Guys, setting up a new plane for IMAC (no 3D at all) and have a question on surface throws/servo resolution. Have programmed the Hitec servos for end points and centering, also happy with the mechanical setup (short servo arm, longer control arm). Also set the DX9 TX at about 140 for initial travel setup. I’m getting about twice the control surface throw that I want and using the dual rate function its taking about 50% to reduce it to what I want and I’m not clear if I’m losing servo resolution doing it that way. Could get a little reduction by changing the mechanical setup but not near enough.

So the question is, what is the correct/best way to solve this and keep servo resolution high? Reset the servo end points with the programmer? Use the TX end point function and reduce the throw that way? Thanks in advance for feedback.

Shorten the servo and control arms

I think it's shorten the servo arm and length to control arm will reduce how much surface deflection you get which will add resolution to give precise flying control

Shorten the servo arm as short as possible (I use 1/2") and then lengthen the surface distance from the hinge line if necessary. Usually that gets me in the ballpark for elev, ail take 3/4" servo arm, 5/8" for rudder. I shoot for a minimum of 3:1 mechanical advantage on the linkage geometry. I run servos in the 120% range max. The only reason for the larger ail and rudder deflections are to accommodate snaps and such. For regular sequence flying I use in the 70%-80% range with lots of expo.

The only thing that matters for maximum precision is that your servo rotates near 100% to get your required deflection on the control surface. If you use dual rates to drop to 50% throw, you are now at 50% precision.