Is there a manufacture out there that make a device that you could run you aileron with that is programmable so you can have the up and down angles different, i.e. some A/C use as much as 15-20° up control, while their down control is ±8°. For a complicated A/C with lots of options I would save a channel.

It's called aileron differential, and most modern transmitters have it as one of it's options. I don't know of any separate add on device. You can do it mechanically by utilizing servo horn and control horn geometry.

Thanks, I did know about the transmitter differential program feature. I am thinking about a project that needs as many channels as I can muster on my Airtronics SD-10G, just to control it, and I may not have enough. If you do the differential program you still need 2 channels.

Yes, you need two channels to program it with your radio.
You can set it with the linkages;
For airplanes with the servo mounted to the bottom of the wing, the connection to the servo should be in front of the center of the wheel and the connection to the aileron horn should be behind the hinge line, if possible. This produces positive aileron differential.
For airplanes with the servo mounted to the top of the wing, the connection to the servo should be behind the center of the wheel and the connection to the aileron horn should be in front of the hinge line.

TLH101, Thanks! The need is fora master scale design where there are no control horns or link showing out side the wing surface

You may be able to introduce mechanical differential for your scale mechanism.

Do you have any picture or drawing section to show us?

http://www3.towerhobbies.com/cgi-bin...?&I=LXCTS1&P=7

You might this out. It says you can independently adjust servo throws


and you might do what you want with Hitec digital servos and their servo programer. You could adjust each servos throws both ways to get what you want.