hi. if it helps i built ds b17 the rudder is the same with 1/8wire with hinges the tube is just a out line on the plans what i did was built the wire into the leaningedg grove to fit . on the bottom of the rudder 3or 4'' i used the plastic tube to go in to fus like a bearing holder and conected the horn it works fine only thing you cant take the rudder off 1/8 wire came about 18''long with 6'' in to the fus my b17 will fly in august its on rcu 138 ws ds good luck