Aileron size

[Skratchbilt]

Is there a mathematical soloution to decide the area of a control surface, in conjunction with the wing area? Am turning a large high-wing into a four channel bird.

[Wojcigitty]

How fast is it going to go? What's the wing loading? What airplane is it? What do you want the airplane to do? All of these determine the size of the aileron; there is no one answer. Try to find something with similar characteristics and copy that.

If it's a high wing that used to be 3-channel, use lots of aileron differential (more up movement than down). Equal throws will probably result in adverse yaw due to higher induced drag on the outside/up wing, leading to aileron ineffectiveness or even reversal. Also mix some rudder to ailerons (start with about 10%).

[Skratchbilt]

Thanks, Wojcigitty... I knew there was no formula for full-size crafts, due to the set perameters of certified planes, and reasoning allows the solution you have given. The modified craft mentioned is a Sr Telecaster... was a 3 channel... has way too much dihedral at this time on its 81" wings... I will dismantle the wings, remake the ribs and spars and build a 2% set of wings. The barn door style ailerons will take up 15% of the suface area, so that it will perform as a full-sized version... low and slow. I am not into aerobatics at all. My planes are all for leizure flight. Mixing the rudder in will help, thanks.

[Wojcigitty]

Cool, the Senior Telemaster is a fun airplane for sure. It will need a lot of aileron differential. Make the ailerons go twice as far up as down, and you should be all set.

Good luck!

[King Snake]

There is absolutely a formula for full determining aileron size and location for a full scale. Essentially what you are doing is integrating the change in lift for each side of the wing across the entire length of the aileron. Its a little complex but not too bad. In the FS world this formula is usually backed up with CFD.