A simple way to route servo wires 

A method for fishing servo wires through wings, especially ribbed wings, is to go to the hardware store and get about three feet of the smallest beaded chain you can find. You know, the stuff like on the pull chain of your ceiling fan, only smaller. Drop this chain in your servo bay, and rock the wing back and forth. The chain will find its way down like water. Tie a string or your wire to it, and pull it right through.