If you have forgotten the put lead wires or string through the holes in your wing ribs for servo wires, it is an easy task to do this. Take a piece of string or yarn and tie an appropriate sized fishing weight or nut to one end. Insert the weight into the wing through the servo hole and place the wing in a direction that gravity will take over. Small shakes of the wing may be necessary and a pair of needle nose pliers or hemostats at the wing root end to grab the weight. Now, simply remove the weight and tie the string to your servo lead and pull the lead through. This also works well when getting elevator and rudder servo leads from the back of the plane.