Installing Rudder return spring

How to keep the Cessna 170 flying and airworthy.

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Bruce Fenstermacher
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Installing Rudder return spring

Post by Bruce Fenstermacher »

I know several people have installed rudder return springs. And there are at least three other threads about the installation with tricks and pictures of the springs and resources for them. Here are a few but not the only thread that mention rudder return springs.

http://www.cessna170.org/forums/viewtop ... f=2&t=7586
http://www.cessna170.org/forums/viewtop ... f=2&t=2404
http://www.cessna170.org/forums/viewtop ... f=2&t=6923


Here is my question for those that have done it or those who have the answer.

When I install the new springs I have coming which way is the hook attached through the rear pedal arm. Hooks pointing to the outside of the tunnel which I'd think would be the harder (maybe impossible) way but stronger or hooks pointing into the tunnel which is doable but may be a weaker method due to bending leverage placed on the hook.

BTW I asked this same question at end of one of these threads but probably no one saw it. (It's unlikely no one has an answer. :lol: )
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GAHorn
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Re: Installing Rudder return spring

Post by GAHorn »

Do it the hard way, Bruce. :lol: :lol: :lol:
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n3833v
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Re: Installing Rudder return spring

Post by n3833v »

I think I did it the easiest way to hook them, hook out if I recall.
I can look tonight.
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jrenwick
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Re: Installing Rudder return spring

Post by jrenwick »

Is it still customary in this group to wait until a guy has installed new springs and described the lengths he went to to complete the job, before mentioning that the easy way to do it is to disconnect one of the rudder cables back at the rudder bellcrank? Just wondering.... :lol: :lol: :lol: :lol:
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Bruce Fenstermacher
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Re: Installing Rudder return spring

Post by Bruce Fenstermacher »

To further illustrate my question carefully look at the illustrations and the direction of the hook as well as the spring. All the illustrations would be the left side of the tunnel just to the right of the pilots seat as viewed from the top. The spring I'm illustration would actually be for the right pedal however.

Tell us by illustration letter which why you installed the springs or which way your springs are installed if you didn't install them.
returnsprint.jpg
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ronjenx
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Re: Installing Rudder return spring

Post by ronjenx »

On my brother's 170A, the springs are as follows:

The spring in the left side of the tunnel is like "A", EXCEPT, the long aft hook points left, outboard, toward the pilot's foot well.

The spring on the right side of the tunnel, both hooks point inboard, toward the center of the tunnel, with the long hook aft.

There is evidence the end of the aft hook, on the left side of the tunnel, has been scratching the tunnel side wall, so I am going to reverse the aft hook, to make it point inboard.
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n2582d
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Re: Installing Rudder return spring

Post by n2582d »

Bruce,
I recommend removing the engine and firewall for better access to install these springs. :lol: While I know that the IPC is not to be used for servicing the C-170, it does show the spring installed with the straight arm facing rearward as in your example A or B. I found that the forward end of the springs only went on as shown in example A and this picture.
P1010663.JPG
The back of the spring should be attached before the front of the spring. On my plane there was adequate room between the tunnel and the spring regardless of which way the loop was facing. It seems to me that there is enough length in the spring that it can be rotated so the attachment hook can face 180 degrees from the forward hook if necessary to attach it to the rudder bar arm easier. Here are two pictures of how the springs attached to my rudder bar arms easiest with the firewall off.
Right side of tunnel
Right side of tunnel
Left side of tunnel
Left side of tunnel
Last edited by n2582d on Wed Jul 14, 2010 5:30 pm, edited 3 times in total.
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Re: Installing Rudder return spring

Post by Bruce Fenstermacher »

Gary thank you for the clear pictures. Here are my thoughts from my first engagement with these springs.

First I suspect that my examples A and B and the IPC are the correct direction as far as the meat of the spring ie the long hook ends would be attached to the rudder bar. From my observation I don't think it matters which direction the spring hook is attached at the firewall end because the attach contact point is center hook either way.

But on the pedal bar side placing the hook through the hole and around to the outside places the attach contact point, which appears to be the hole, to inside the hook with less bending arm than placed the other way where the attach contact point is on the outside of the hook leading to a longer bending arm. The longer bending arm I'd think would lead to the hook breaking off easier. This can be seen on your pictures with the right side having the longer bending arm.

So I'd think attaching the spring as in your left photo would be better however I think with the firewall installed it would be impossible to actually do this.

I'm probably making more out of this than need be and should attach the new springs anyway I can get them in. :roll:
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jlwild
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Re: Installing Rudder return spring

Post by jlwild »

Bruce and Gary,

With all the research and work you both have done about installing the rudder return springs, why don't you jointly write an article for the 170 1/4ly News :?: It would be a great way to document your work with pictures and reach those who still don't use the website 8O :D Plus this would make a great discussion topic at some future Convention MX Forum 8)

Might even be a way to give George a rest :lol: :lol: :lol:
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Re: Installing Rudder return spring

Post by Bruce Fenstermacher »

Give George a rest! 8O If I recall I ran a huge very informative and successful maintenance forum last year at Duluth. George was no were to be found but rumored to be sipping St Pauly Girls in Texas with Ol Gar will they discussed the maintenance they should have done months prior to Ol Gar's bug and mouse decoy he keeps at George's place. George should be plenty rested. :P

Jim to this point I actually have only installed a temporary 'owner produced part" on the left side. I do have two brand new springs to install as soon as I'm off work next week.

Besides the tool I showed previous (long handled duck bill pliers) I have an idea for a simple tool to make installation easier. I hope so easy that given the right circumstance for the maintenance forum (and with the oversight of an A&P) I might uninstall and reinstall at least one side. But I might be getting ahead of myself as the tool has not been tried yet.

If I am successful we'll have to take some pictures and write an article.
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jrenwick
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Re: Installing Rudder return spring

Post by jrenwick »

N9149A wrote:Besides the tool I showed previous (long handled duck bill pliers) I have an idea for a simple tool to make installation easier. I hope so easy that given the right circumstance for the maintenance forum (and with the oversight of an A&P) I might uninstall and reinstall at least one side. But I might be getting ahead of myself as the tool has not been tried yet.
I replaced one of these a bunch of years ago. If memory serves, the broken spring still had the long end on it. I wrapped duct tape around the body of the spring to make a comfortable handle, and I used the hooked end of the spring to stretch the new spring over the lever on the pedal shaft. As I said, "if memory serves." Does this make sense to anybody?

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Re: Installing Rudder return spring

Post by n2582d »

N9149A wrote:But on the pedal bar side placing the hook through the hole and around to the outside places the attach contact point, which appears to be the hole, to inside the hook with less bending arm than placed the other way where the attach contact point is on the outside of the hook leading to a longer bending arm. The longer bending arm I'd think would lead to the hook breaking off easier. This can be seen on your pictures with the right side having the longer bending arm.
I'm curious where those of you that have replaced broken springs have found the spring broken. Does the spring wear through where it contacts the front or rear attach point? Or possibly wear and break where it rubs against the "L" flange of the rudder bar arm (assuming it was attached opposite of the pictures below)?

So here is how I would attach these springs. Again, there is only one way the forward end of the springs will attach. But, as you can see in the picture of the left side of the tunnel, the spring ends are twisted 180 degrees from each other. This keeps the spring from chaffing on the "L" of the arm and minimizes any bending load as Bruce indicated.
Right side of tunnel
Right side of tunnel
Left side of tunnel
Left side of tunnel
jlwild wrote:Bruce and Gary,
With all the research and work you both have done about installing the rudder return springs, why don't you jointly write an article for the 170 1/4ly News :?: It would be a great way to document your work with pictures and reach those who still don't use the website
Having never done this with the firewall in place I'm afraid I'm disqualified--or should I say unqualified--to write this one up. Bruce is welcome to use my pictures for his article though. :D (This has previously been written up by Eric Taylor on pg. 7 of the 2nd quarter 2004 issue of "The 170 News.")
Last edited by n2582d on Sat Jun 26, 2010 8:14 pm, edited 1 time in total.
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Re: Installing Rudder return spring

Post by Bruce Fenstermacher »

Yes that might have worked John. I think the first step in this project is to first understand exactly what it is your trying to accomplish. Just looking at an assembled aircraft it is very difficult to see the area and the points specially the forward point that the spring attaches.

The next thing you will realize is you can't get your hand in there and when you attempt to jam your hand in the work space any view of the area you had is now blocked.

Like I said before at least two hours of sweating and cussing until you engineer a solution and you can up the degree of difficulty if you don't realize disconnecting the cable at the rubber would be helpful. Actually it might not be necessary to disconnect the cable but simply rotate the tail wheel backwards releasing the swivel and allowing the rudder to freely swing from stop to stop.

I've have more I'm sure next week after the new springs are in.
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Re: Installing Rudder return spring

Post by Bruce Fenstermacher »

Gary those are more excellent photos of the spring and attaching points. But I have to disagree with one of your statements. It is very possible to hook the front on in the opposite direction than you show. I did it several times while I engineered my first "owner produced" part.

My spring was broken at the beginning of the longer hook at the end of the coils. I had no idea there should be a long hook on one end so the spring currently installed on the my left side is about 1" shorter than it should be.
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Re: Installing Rudder return spring

Post by Bruce Fenstermacher »

After closer inspection of your photos Gary I would agree that I would install the springs as you did for your installation. With these photos it is clearer that the load is placed almost in the center of each hook. It doesn't look that way on my airplane from the bad view that can be had of the situation.

Also I'll say it again that I think it nearly impossible to hook the long hook in the direction you have it in the left tunnel photo while the front is also hooked. It might be possible to hook the long hook at the back on the bar and then hook the front but I can't see that happening without some special tool to stretch the spring forward and twist it into place.
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