Found a crack in tail post

[swhitaker12]

Not factory that I can find. I searched every Pacer/Tri-Pacer fuselage drawing and nothing about a sleeve, couldn't find it on the tail post drawing either. That is why we sleeve it. Maybe you can get the next size smaller tubing into the sleeve someone added. The existing sleeve might be enough but from what we have seen I see no reason to leave those holes there.

Doesn’t Frogdad’s post near the top (post #6) with the pdf show a sleeve reamed? Looks like part number 21121-8.

I agree...something needs to be done to address the area before it becomes an issue. Think I’ll go with a sleeve from the top rosette welded to kill two birds with one stone.

[JPerkins]

Somewhere, I think in Andy's restoration thread; Brian shows his proven method of sleeving it. If I remember correctly (which I probably am not so verify first) it's a piece of 5/8"x .058" wall tube inside a 3/4"x.058" wall tube both 9" long and butt welded together. Then run up into the post and rosette welded through the bolt holes as well as butt welded on bottom.

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[Steve Pierce]

Doesn’t Frogdad’s post near the top (post #6) with the pdf show a sleeve reamed? Looks like part number 21121-8.

I agree...something needs to be done to address the area before it becomes an issue. Think I’ll go with a sleeve from the top rosette welded to kill two birds with one stone.

Found it. It is on the Tri-Pacer Frame-, fuselage fitting drawings. All of the Tri-Pacers had it and none of the Pacers. Most have been for the piece to keep you from striking the tail. It is sleeve number 21121-8 which is 3/4" OD x .065" wall and 2 5/16" long. I would make it longer.

[violinmaker]

I just finished mine. i have a naked airframe so no fabric interferancees.
I didnt have cracks but I did have holes and deep pitting in the lower longerons just behind the brace bracket. So I had
to cut the longerons out. It had an old repair there where they had a 1 foot long inner tube splice starting just forward of the
rear TW bracket. I decided to cut the longerons off about 1 foot rear of the last box section. This allowed me to just make a new run of tubing from there to the rear and into the TW bracket. Instead of using a loose liner tube inside--- I used metric 17mm in the inside which was a perfect fit inside the outer tube. No slop. Could just slide it in. I cut the liners long so they ran from the last intersection all the way to the rear--- so the longerons were fully sleeved. I put on a new tail wire
bracket since it had some pitting from prob. mud or snow laying in it--- same spot the longeron tube holes were.

The tail post was OK but I added a sleeve all the way from the bottom to the edge of the finpost. Instead of trying to remove the short sleeve at the bottom--- I added a 2-nd sleeve into the tip of the main sleeve--- so the 2-nd sleeve stub
fit tight into the short bushing and came out flush on the bottom. So I have LOTS of meat on the tail post and longerons.
I also fabbed a short sleeve and put in inside the forward spring bracket to prevent it being collapsed by the bolt. Lightly
welded in on both ends to keep water out ( thanks steve--)


Beware-- there are 2 slightly different tail spring brackets at Univair. Pick carefully
I am ready to start priming from the tip of the tail up to about the baggage area----
That was a lot of work--- but I just took my time with it to get it to my liking.

Tim

[Shermanj1]

So just to keep this subject going, I found a crack in my tail post. What seems to be easier buying a tail post from wag aero and install or fabricating. Either way a sleeve seems to be in order. Also how difficult of a project is this, I am a newer A&P with little welding experience.
IMG_1620[1].JPG

[at7615]

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[violinmaker]

Sherman--- I guess it would depend on how the longeron tubes look inside once they are cut off/open....
The tail post is just a simple piece of pipe aside from the hinge brackets. But the post is about 125 $ or so i think---
I had a lot of time in cutting the welds between the smaller diagonals and the lower longerons. (so as to preserve
the interface for welding the new connection there- so that the joint was tight ) Same with the longeron to post joints.
Slow and time consuming.... but I didnt want any gaps--- the tighter the fit the easier the welding goes.
The HARD part was doing the welds on the inside faces of the longerons. Hard to maintain gas coverage there --- even with foil dams. The rest of the welds were not so bad. Just a lot of hours though.....

Ps-- 17 mm OD tubing slides into the longerons perfectly with the min. of interference---- any tighter and you couldnt move it---
I ran them from the post to about 1 inch past the first station. That way I had a double wall tube there they connected to the post. (fused the ends together after the tube and liner were coped so I had good thermal contact between them- when making the bead to the post. )

[ctracy]

Hello,

I could use some advice on the repair of my 1950 PA20. I discovered that the tail spring bracket was loose a few weeks ago and after propping up the tail I can see that some time ago one of the welds on the tail wheel spring bracket had broken and it has been working fully loose ever since. After pealing back the fabric I can see that I was darn lucky it didn't come loose completely on the last landing. The bracket took with it a chunk from each of the lower longerons and the tail post so simply welding on a new bracket isn't possible.
From digging though the archives here I can see that this is a fairly common problem and many of you have cut out the bad sections, sleeved and welded in new sections of longeron and tail post. What the existing posts are missing is the paperwork related to the repair. The repair path seems clear to me but my mechanic seems to think it is almost impossible from the perspective of the FAA. I live in rural Oregon without a lot mechanic options. He is a good guy but has almost no experience with tube and fabric aircraft.
How have you done the repair in the past and what is required for a sign-off? I included a picture of how it looks now and one of how I would like the repair to look. Thoughts?

IMG_2423.JPG IMG_5897.jpg

[dgapilot]

AC43.13-1A Chapter 4 provides all the approved data required. Just remember that each paragraph and figure needs to be cited on the 337 per the signature page.


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[Steve Pierce]

Yep, AC43.13-1A Chapter 4 shows the inner sleeve and outer sleeve methods.