Bent tailwheel steering arm

[bagarre]

Somehow (I really don't know how) I managed to bend the steering arm on my tailwheel 90 degrees straight up on the right side.
Right flat against the tailwheel, it's bent straight up like I put it in a vice and whaled on it.

The ONLY thing I did out of the ordinary today was show my wife what a groundloop looks like and no, that's not an excuse for an accidental looping I explained what was going to happen, taxied rather slowly and let it go around very controlled....and didn't hit anything.

But, when we got back home, the steering arm is BENT.
I tried to bend it back with my foot but that steel is tough! I'm guessing if I tried to bend it back, it would be severely weakened anyway.

So, since I'm going to open the tailwheel up to replace the arm, is there anything else in there I should go ahead and replace?
Until now, the thing has never given me any trouble.

[Bruce Fenstermacher]

You might want to replace the pawl Scott part 3219 and the spring Scott part 3222 because these things wear against the control bracket. But being frugal I wouldn't until they break,

[GAHorn]

After your demonstration, did you actually inspect it?.... or did you say, "and that's what a ground-loop is like...." ...and then proceed to fly home?
You must have hit something unseen (chock or tie-down ring anchored in concrete, etc..)

IN any case, if you didn't get the inside-wheel to lift up off the ground you didn't do a "groundloop".... you merely "pivotted" or "pirouetted" about the inboard. (Down here in Texas, we frequently do that at the barn-dance, where it's called a "dosie-doh" , usually performed immediately before a "right-hand-grand")

[bagarre]

Sadly, I didn't think to inspect the plane after as it was such a non event. The wheels stayed on the ground and there wasn't even a thump of hitting something. Either way, I did something cuz that arm doesn't bend easily.

The pawl and spring are a good idea. I'll give them a good look when it's apart.
Good time to swap out the tail spring too.

[Robert Eilers]

When I was flying my Champ, for the first two weeks after purchasing it, I would ground loop either other landing. I couldn't figure out what was going on until inspecting the tailwheel spring. I discovered the leather shims had come out allowing the tailwheel spring to twist almost 445 degrees. You might take a look at your fish mouth and make certain your tailwheel spring is not twisting when side force is applied to the tailwheel.

[blueldr]

George,
As an apparent expert on danceing the "Texas" way, do they still dance the "Varsoviana" at least once at all the dances in Texas? In my wildly misspent youth, I used to court my late wife by going to the Seven Oaks Country Club in San Antonio for their Saturday night dances. They always had a great dance band and danced to "Put your little foot, ---" at least once during the evening.

[GAHorn]

bluElder, there are several dances that are traditional in Texas, including the "varsoviana" (which has Spanish/Mexican Revolution origins) and you were actually captured in an old "still" photo of one, hosted by your dear old friend, Pancho:
http://www.youtube.com/watch?v=iBI1nwMzUGE

Another favorite tradition is the "Cotton-Eyed Joe"...usually quickly followed bya "Schottish":
http://www.youtube.com/watch?v=ARt5F7ynWvI

[blueldr]

Boy! How that stuff takes me back to San Antonio of about 1947 and the Seven Oaks Country Club in Alamo on the north side of town.

[WSHIII]

Sadly, I didn't think to inspect the plane after as it was such a non event. The wheels stayed on the ground and there wasn't even a thump of hitting something. Either way, I did something cuz that arm doesn't bend easily.

The pawl and spring are a good idea. I'll give them a good look when it's apart.
Good time to swap out the tail spring too.

Well, I don't know what's causing this either but it happened to me today as well. Not quite as pronounced as yours but the right side is now bent up substantially more than the left. I Changed the leaf springs out yesterday and that seemingly got rid of the nasty shimmy I had. Flew some yesterday and then again today, back and forth between paved runways. Then pushing the airplane back in the hangar this evening I noticed what had happened.

Very strange!

[c170b53]

How about a picture, so we can see the chain guard install and other spring area attributes so that may have some dart material.

[bagarre]

It was at least a good excuse to tear down the tailwheel and replace some worn parts.

Steering Arm (got a heavy duty one, plus new dust caps)
Compression Spring
Main Bushing
Both dowel pins ( The 1/4" one was almost flush. wasnt long before the thrust bearing would be torn up)
Grease seals
Tab Lock washer
all nuts and bolts
The main leaf spring
..and paint it all a nice grey.

[jlwild]

Strange! Two planes with bent tailwheel steering arm. From the discussion it sounds like it happened during a turn. Do you have the correct tailwheel steering springs? The compression springs, which are a no-no, can do damage to the pulleys, brackets and aft bulkheads. Suggest you also check those areas. Let us know which type of steering springs you have on the plane. The dangers of compression springs have been discussed in several areas on the forum in the past.

[bagarre]

Yep. I have the tension springs, not compression springs and the chains are 'snug' when sitting on the ground. (one more link woudl make them slack). Springs attached at the rudder horn.

Looking the IPC, Figure 28, I seem to be missing the tail wheel steering chain guard ( PN 0442125 ) but have the Spring Shackle (PN 0542108)
Not sure how that could bend the arm tho.

[WSHIII]

Strange! Two planes with bent tailwheel steering arm. From the discussion it sounds like it happened during a turn. Do you have the correct tailwheel steering springs? The compression springs, which are a no-no, can do damage to the pulleys, brackets and aft bulkheads. Suggest you also check those areas. Let us know which type of steering springs you have on the plane. The dangers of compression springs have been discussed in several areas on the forum in the past.

Well, I definitely have compression springs! Ive only had the airplane about a month now and that's what was already installed. Had no idea that those springs are a "no-no" on the 170. Anyway, I'll switch them out tomorrow and give everything the once over. Thanks for the heads up.

I'll try and post a picture.

Any suggestion where I can pick a replacement "heavy-duty" steering arm?

[Bruce Fenstermacher]

Hard to say what happened here. Bent tailwheel control horns are not unheard of but it is not a daily occurrence.

Our 170s tailwheel control chains have a terrible angle at which they pull the control arm around its travel. The pull up or the arm as much as they pull front. the '55 arrangement was an obvious attempt to improve this pull angle.

It does not take much to stop the tailwheel from turning the way it should. Caster angle and wear play a quick toll with the result that the control chain pulls up on the arm. The weakest link in the control chain from you foot to the wheel is the control arm and it bends. This is probably a good thing as the other parts are hard to inspect and fix or replace. The '55 arrangement with the added pulleys adds an area of flex besides the control arm and we are seeing more and more reports of cracked bulk heads around the pulleys.

The tension springs are meant to be that point in either system than gives as necessary without benting parts. Tension springs of course have a limit to there stretching capability on to the extent that at some point they won't spring back as far as they once did and the system becomes loose but no real damage other than replacing the springs. I've never actually seen proper 170 tailwheel control spring stretched.

The compression springs on the other hand have a limited compression travel. At full compression the excess load has to go somewhere and it is the steering arm or in the case of the '55 the bulk head. Compression tailwheel control springs on a 170 are bad news.