I am in the process of building my third plane and it is the first one to use a "pull-pull" rudder. The kit comes with two lengths of piano wire and four clevis's to be silver soldered to the ends of the wires which are then connected to the servo and the two control horns on the rudder. So I have the servo installed and the wires connected at both ends but for some reason I am not comfortable with this arrangement and keep looking at the four soldered connections and wondering when the first one will experience some form of fatigue and break. I also have plastic "pushrod exits" installed on the fuselage at the place where the wires exit the fuselage near the rudder but when I look at the tension on the wires it occurs to me that it will not take long for the wires to cut through the plastic and start to eat into the sides of the fuselage.

My prior building experience has been with Sullivan plastic pushrods inside plastic tubes and so I am thinking I will replace the piano wire with the Sullivan pushrods (with or without the outer plastic tube). This will give me a better connection at both ends (threaded rods screwed and glued into the pushrods with the clevis screwed on the other end of the threaded rod) and the plactic pushrods will not cut through the pushrod exits or injure the fuselage

I understand that the plastic pushrods have a problem if they are not properly supported in a standard "push-pull" arrangement but they should work well in this "pull-pull" setup and solve the problems I am worried about.

Has anyone tried this type of thing before or know why it will not work or why the piano wire setup is superior in any way.

Coyoteee

pull/pull system is easy to set up and adjust,it's slop free,and in my opinion the better system,you will have the same amout of control both directions, something not always with the sleaved rods,give the pull/pull system a chance,over the years I've used a lot of different control systems and the pull/pull is a favorite of mine

I've never used piano wire on a pull-pull rudder. I have only used piano wire for the throttle. I have 3 planes set up with a pull-pull rudder. One uses a cable which is soldered to the clevis's, one uses standard push rods screwed on to plastic clevis's and the other one uses kevlar string which is tied in a knot to the clevis. When you look at the kevlar you think it will not hold but it is extremely strong. Your piano wire should never touch the pushrod exits. If it does then you may need to install some with larger holes. I agree with TerrellFlyer, it is a better system than push-pull.

Just my 2 pennies worth...