Rudder pedal return springs

[TY2068]

Does anyone have a preferred non-standard rudder pedal return spring they use on an IV. My springs don't seem to give quite enough return pull. To me they look a bit dinky and undersized. I'm sure they are the original ones supplied with the kit. Should new ones be ordered from Kitfox or has anyone found some better ones at Spruce, CPS, Ace Hardware , ect ?

[jiott]

I have a model SS7 but have noticed also that the springs seem marginally adequate. If I keep the rotating joint for the rudder pedals lubed the springs do all right, but if that pivot becomes somewhat dry the pedals don't want to return easily. The pivot joint is not easy to lube; I use the light penetrating spray LPV-1 which seems to work the best.

FYI for you builders, this pivot joint needs to be worked on with emery cloth to make sure it is very free and lubed before you permanently assemble the rudder pedals.

[HighWing]

Personally, I have never considered it a problem. This has been discussed before in the old days to the point that one guy wanted to put a line behind the pedals counteracting the pull on the rudder cable - essentially replacing the springs with a cable loop that would then, with the help of a turnbuckle for adjustment form a tight continuous loop with the pedals in the middle. Theoretically you could then give right rudder by tucking your toe behind the left pedal and pulling with your toe.

In my minds eye, the only purpose of the spring is to put sufficient tension on the rudder cables that when at rest, the cable doesn't sag to the point that it snags something - this in the cockpit area only. In practice - when flying - the foot resting on the pedal provides the return forces needed to keep the cables secure. With our tendency to need a little right rudder most of the time, I don't think the intention of the springs were to allow us to fly with only the right foot on the rudder utilizing the spring to counter aerodynamic forces. Just one guys opinion and was just there on my Model IV Annual Condition Inspection. Curiosity prompted me to just go out and check pedal movement while manipulating the rudder by hand. The external portion of the cable remained straight and the pedals moved as I moved the rudder. If you are finding that by moving the rudder by hand you get a sag on the visible cable and the pedals don't follow the movement, I would suggest finding what is causing the friction on the cable or the pedals themselves. Then this brings up one more thought. When helping on my friends Lancair - the fuselage being a porpoise shaped carbon fiber shell - the rudder cables were run through continuous Nylaflow tubing glassed to the wall of the continuously curving fuselage outer skin. When building my current Model IV, I used the same concept as the cable enters the Nylaflow just forward of the seat and exits just before the cable passes through the fabric skin. Unlike the Lancair, the tubing is attached to the fuselage framework at similar locations to what the manual calls for, but the tubing is not in short sections. Maybe it is the much lower coefficient of friction of the Nylaflow vs. the Polyethylene tubing or possibly only the two enter/exit points but the system is very low friction.

Jim mentioned the 7. Just me, but not a fan of that design. Aesthetically much better, but as he mentioned, it has issues all its own. With the IV and before, the pedal pivots shouldn't be as challenging.

[TY2068]

Jim I lubricated and checked everything and it all looks fine. Lowell hit upon the "problem" so to speak in that when you move the rudder by hand the pedals aren't following. Of course with feet on the pedals everything is smooth and tight. I'm thinking just a bit more spring tension on the pedals is all that is needed. Maybe these original return springs are just getting a bit tired. Just one more thing that passed a condition inspection that has me wondering ? Thanks for the input guys.