During the weeks I was working on my first plane, every weekend was perfect; 70 degrees, no wind, and plenty of sun. I finished my plane on a Friday and there has been thunderstorms every weekend since. So, on those rainy days I have been on the Internet trying to learn everything I can for my next plane.

Anyway, while I have been looking I have seen something I don't understand. On large models that use a separate servo for each aileron, the servo has usually been mounted on the underside of the wing. The control horn for the aileron is almost alway positioned near the fuse. I have seen this on everything from balsa kits from Sig and Great Planes to scratch built SPADS. Why wouldn't you want the control horn to be centered on the aileron?

A perfect example of this can be found here: http://www.rcuniverse.com/showthread...842&forumid=58

The only thing I can figure is by keeping the servos close to the fuse the model is more stable and you want to keep the control rods square with the control surface. Or am I way off base??

I can only speculate as to why the delta wing builder you used as your example chose the spot he did for mounting his servos. I can tell you, however, when I build a plane with the servos on the wing, my placement is dictated by the length of the servo lead. I do, however place my servo as close to the center as I can. In some cases I have to use a servo wire extension to get the placement I want. In most cases it is mostly pilot/builder preference.

For optimum results, you would like the horn to be nearer the tip than the root. It is best not to put it in the direct center as that will maximize the onset of flutter at one particular frequency; put it out at about 3/5 span. The disadvantage, and probably why you see so many mounted inboard is that the length of the aileron extension is much less.

Not always, it depends on the model. It has nothing to do with stability. If it's an aerobatic plane that will have high flight stress on the ailerons, then the servos are usually located near the center of the aileron if possible.

It comes down to:

Do you want to buy 2 servo extention cords or not?

For most designers it's more to keep the weight of the servos more towards the centreline of the aircraft.

I like to place mine more to the center of the aileron , with the horn mounted thru the center hinge , and the other hinges spaced equally to either side ,

again just my preference ,

Highlander

to be precise, It should be in the line of the center of gravity of the aileron