It is my understanding that:
A) a servo wheel turns about 90 degrees;
B) the more overall rotation of the servo arm the greater the resolution of the control;
C) more up than down is preferred for the aileron;
D) little or no down aileron with mostly up is preferred in a model, to help prevent stall out and diving in opposite direction to control input.

Questions: If above statements are correct (comments please), what is the affect of mounting the servo arm at positions other than at 90 degrees to the hinge line?
The star arms furnished have different offsets (Thanks Minn Flyer) and a straight arm could be adjusted for greater amounts.

I would like to understand which direction would accomplish more up than down.

Would this not also help in setting up flaps, but in reverse?

On a low wing plane with typical strip aileron torque rod actuation, (servo on the top of the wing) moving the servo arm attach points towards the rear (behind the servo output shaft) will cause more up than down aileron movement. The opposite is true of high wing planes with the servo mounted on the bottom of the wing.

You don't want differential aileron throw on a symmetrical wing pattern type plane because you would have reverse differential effects when inverted.

A) a servo wheel turns about 90 degrees;
OK
B) the more overall rotation of the servo arm the greater the resolution of the control;
Yep, if you dial down the "volume", it really just reduces the number of digital steps. Still, there are a LOT of digital steps. THe resolution change is more academic than apparent.

C) more up than down is preferred for the aileron;
Yep, on a flat-bottom wing especially.
D) little or no down aileron with mostly up is preferred in a model, to help prevent stall out and diving in opposite direction to control input.
No, it's to reduce adverse yaw, where the down-moving aileron acts as an airbrake and the fuselage yaws, for example, left, when the pilot is commanding a bank to the right.

For differential travel: If you are using a single central aileron servo, and you set your pushrod connections at the 3:00 and 9:00 position on the servo wheel, you should get equal travel up and down. If you set the pushrod connections at 10:30 and 1:30, you will get almost all up and almost no down.

Jim

Thanks for the clarification. I may have used the wrong example (Ailerons) in my first post. I follow the logic in your reply. Going to have to read up on plane reaction to adverse yaw. the 1030 130 example clarified.

If you were setting up flaps with individual servos on each wing half, do you see any advantage in positioning the servo arms closer to the 10:30 (port) and 1:30 (strb) positions? I'm thinking of a limited (3-8 degrees) of UP FLAP position as a possible trim assist. This would be set to a VR switch would be active , unless some other mix switch involving the Flaps (E to F, or A to F couple) were activated.

dickeybird: Still digesting your info....

>>unless some other mix switch involving the Flaps (E to F, or A to F couple) were activated. <<

If your transmitter will do all this, you can program differential aileron anyway, with the end point adjustment (volume) control.

The radio, 9CAF, provides that programming. This post is to assist in my understanding of the aero principles and mechanics of the physical rigging.

You can also build some of this in, by hinging your ailerons toward the top of the surface, rather than in the center.

I have being programed that down is only drag NO AE ever showed me on paper or. But down suppose to give the turn
a sluggest movement. Maybe CU

The aileron differential is meant to counter adverse yaw that can occur in some aircraft. For models this is usally long aspect ration gliders or electric assisted gliders. Typically sport power models don't bother with differential. I suppose some of the basic trainer types would fly a bit better with a 60-40 differential ratio but it's not a big deal in my book. Certainly any sort of aerobatic model would use symetrical throws ( no differential).