I am looking for some help with a dimension for the set back, or forward of the rudder horns on the following set up. Servo horn= 2in. Rudder horns 2 5/16. wires are 23 1/4 in long and the wires are CROSSED! What dimensiuon do I need to have the wires not tighten or loosen as the rudder deflects. Rudder throw is approx 45degrees. Any help is appreciated. The horns are currently on the hinge line and the wires loosen at full deflection.

No doubt you will get a lot of more or less complicated answers to this question but in order to keep it simple:

If the wire loosen at full deflection you could either move the rudder horns a little bit forward (ahead of the hinge line) or move the attachment points on the servo horn a little bit backwards (towards the rudder).
If the wires are tight when the servo is in neutral but loosen a little under full deflection that is usually not a problem.

/Red B.

Hi!
You can use whatever dimension you like ...within reason ofcourse. Just use whatever servo arm you like ...preferable as short as possible at the servo and make the rear rudder or elevator horns as large you like ...short at the servo and large horn at the rear is what one should always strive for to have a tight set-up.
I always use wires whenever I can...in my 375km/h pylonracers as well as in my sport airplanes and scaleairplanes. Wires could be bought in fishing stores.
See pictures of my Great Planes GEE BEE R-2 ARF airplane.
Regards!
Jan K
Sweden