The International Cessna^® 170 Association

Within the last week or so my rudder has somehow become misrigged; at cruise it is a full ball + out to the left (requiring left rudder).
On the ground, if I raise the tailwheel with it centered, the rudder is deflected to the right.
Any thoughts on what is causing the "preload" on the rudder? I'm thinking it might be the tailwheel chains / springs, although nothing has changed there to create tension. No hard / rough landings. Flew off grass a few times last week, but they were exceptionally smooth fields and the landings were fine.
If the chains were somehow stretched, a shorter chain on the L side could pull the rudder off to the right ... but I would think something that would stretch a chain would likely be noticeable from the cockpit.
Any other thoughts?

Thomas

So you are saying that with the tail in the air the rudder will be pulled to one side like it's under pressure?

If so it probably is because one of the rudder return springs at your rudder pedals has broken.

Of course your tail wheel could be stiff and stuck in a crocked position which would pull on the chain and spring but this is pretty obvious and I don't think you'd be asking us about this.

Yeah, it is pulled to the R maybe an inch or inch and a half at the TE.
I'll look at the return springs next time I'm out there. Are they tough to replace?

Thomas

No they aren't. I used a rod or long screwdriver to slide the hooked end up to engage and poped them in. It looks worse than it is due to the access.

John

I've not done it myself but have looked at it and read several tips here at the forums as to how to do it easier.

Appearantly it can be a real pain if you don't understand what you need to do and what you can do to make it easier.

The rudder springs are easy to replace if you disconnect the control cable at the rudder and reconnect them from the access beneath the airplane (my transponder antenna is fastened to the access plate that I use). I have put them on so many times now that I can do it in under five minutes. You can do a search on this topic and find out more.
David

Could this be related to your fuel feed problem? Bill K

What Bill is trying to point out Thomas is perhaps flying out of trim has caused the unequal fuel flow.

No way! I would never fly out of trim!

Actually I thought of that but I have been very conscious of flying well coordinated since I noticed the rudder problem. I don't think they're related, but I could be wrong.

I went to the airport today and pulled the inspection plate on the bottom under the rudders ... sure enough, the return spring on the R side of the airplane is broken! Now, just gotta figure out how to get in there and replace it. Looks like approaching from the top might be easier ... ? The parts dept at my FBO hadn't sold one of those since 1990 and elected not to stock it any longer ... go figure. Not many taildraggers at this airport.

Thanks for the input - it probably would have taken hours (and maybe $) for me and / or someone else to figure that out. Membership paid for!!

Thomas

Thomas, it should be pretty easy. Disconnect the control cable at the rudder, take off the access panel on the bottom of the airplane, put a small flash light inside the fuselage pointing toward the ruder pedals, you should be able to move the arms that the spring attaches to without restriction, put the spring on the rear arm, then on the forward arm (at least that is how I do it). There is one way that you hook the spring that will allow it to unhook if you are to vigorous on the pedals, and another way that is a little harder to install but is more secure...hence the reason I have done this so many times. You will have to look at it to see what I am talking about. I am lucky in that I don't have huge hands or arms, and I can reach up there faily easily. If you are a big guy you might have to get someone else to reach up there. I believe that the springs are the same for several of the cessnas, so you shoul be able to find them for less than about twenty bucks. Hope this helps.
David

You might have to file the burrs off the end of the spring hook so that it will enter the holes easly.

I had this happen to me, but instead of the left spring having broken we found that it had simply slipped out of its hole but slid down and hooked on the little arm that normally connects the spring to the rudder pedal assembly. So it still provided some return on the left side, but not enough to provide pull equal to the right side, and the rudder was not completely neutral. Mimicked a heavy wing I swear. Put the spring back where it belonged and it flew straight and true.

I ordered the spring today - got one of each.

How are they designated? The parts manual is not clear (at least mine is not - it is the original and quite old).

The spring on the right side of the aircraft goes to the L pedals and vice versa. So is the R spring part the one on the right side of the plane (my guess) or is it the one that controls the R rudder?
I'm sure it will be obvious when they get here as they are different lengths but I just wondered what the convention was as far as naming.

Thomas

Thomas,
Your guess is correct. The left rudder bar--the forward one-uses the "right return spring", p/n 0310196-3. This is mounted to the right side of the tunnel. Hope this left you with the right understanding!

Most items in a left/right designation have an odd/even number or dash-number.
(Usually, when looking at right/left-handed items on an airplane, ...an even dash-number is the right side, and an odd dash-number is the left side... but in this instance apparently Cessna ignored that convention on these rudder return-spring parts. The right spring is PN 0310196-3, while the left spring is PN 0310196-4.) Thomas may have figured out why.