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Cracked fuselage

J

jadebons

FRIEND
Southern MD
We walked into the hangar this morning with the intention of doing a 100-hour on the PA-12 on EDO-2000 (has increased GW STC, PA-18 gear STC). It's been performing remarkably well for the two years I have owned it. Walking up, I noticed a wrinkle in the fabric just forward of the lower door. Pushing on the tube forward of the wing strut attach fitting, I discovered that it moved... a lot! Walked to the other side and pushed that tube. Same thing. Razor blade came out and we found two cracks all the way through the tube on the right side, and one on the left. This has been an area that we have looked at during preflight and postflight and it seems that the airplane just "had enough" sitting in the hangar for the week. There is evidence (existing corrosion) that one of the right side cracks has been there a while. There is evidence of corrosion on other tubes, and I expect to find other issues as the fabric comes off.

I suspect that a combination of things are at fault: 22 years since last covering, two-time flight school airplane, at least one wheel ground loop, and XXX landings). Is this a normal area for failure?

Anyone have a fuselage for sale?

Thanks,
Jeremy0829201511a.jpg0829201511.jpg
 

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Jeremy,
Will be interested to hear what the experts say here... Being that I have a 12 that is torn down from a ground loop incident. Do you think this is from the floats beating on the attachments? Like I said in my email, you wings and my fuselage we could have a Franken-12!
Andrew
 
Isn't there a section of tubing that needs to be added to that same fuse area to a 12 that is going on floats?

Glenn
 
Hmmm. Never seen that.... but I’m mostly around wheel planes...

But that doesn’t make sense on floats since that fitting is not even attached to the floats....

Only thing I can think of is it was sunk and that’s where the water collected and did internal corrosion


Sent from my iPhone using SuperCub.Org
 
Hey Glen , I just looked at my 12 frame and there isn’t and tube’s. Could you send a ruff drawing of where to add them. Glad I saw this before I Got any further.
 
cubdriver2 said:
Isn't there a section of tubing that needs to be added to that same fuse area to a 12 that is going on floats?

Glenn
Click to expand...

no...

the added tube goes from the FRONT LEFT gear fitting up to the front left wing attach fitting... this shows REAR fitting by cracks
 
278BF22A-2EC1-4F43-B554-D9C73BE4608E.jpg I think this has the tube
 

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I would not be surprised to find a break most anywhere in a factory 12 fuselage. I have seen a hard working 18 with a break between the gear fittings. Also happen to have a ski at that side with a big hunk of plastic missing!:oops: The plane is talking to you, time to listen!!! Suck it up, go to bare frame and sandblast. Replace tubes or fuselage as needed. Budget 30 grand and take a lot of tylenol because MOREBETTERFEVER will hit. OH YA how old is that gear???
DENNY
 
My -12 would like to collect water when tailed up on the shore. I forget if it had seaplane drain holes near the gear and struts or fuselage stringers. Even so they tend to plug up with gunk from boots and dogs. Sometimes when turned around and pulled up nose in to fuel water would run out the open area near the spring mounts. Zinc chromate primer over steel as I recall.

Gary
 
Bet it's time for at least lower longerons on that old girl. And maybe a fuselage according to what the rest of it looks like.
 
algonquin said:
Hey Glen , I just looked at my 12 frame and there isn’t and tube’s. Could you send a ruff drawing of where to add them. Glad I saw this before I Got any further.
Click to expand...
I'm not good at searching here. I seem to recall a discussion with drawings here a year or so ago. There were a couple of different versions of this extra tube installation.

Is there much fresh water in Maryland for seaplanes or has this -12 been used in salt? Salt water and seaplanes is not a good combination.
 
I will have to look at the PA12 drawing but I know on the othe Cub fuselages there is a liner tube in the longeron right there. Could be corrosion, bad repair etc. Time to investigate and look the rest of it over real good. Fix what you got if economical or buy a new fuselage from Univair.
 
We were already planning a fuselage recover this winter. This just accelerated the timeline. The fuselage was modded in 1998 with PA18 gear, GW increase, Skylight X brace and for floats. It has had a hard life. Based on corrosion found at one of the cracks, it had been there a while. We will be adding more drains and access panels for cleaning and lubrication.

I have operated on floats for 2 summers on brackish water. We rinse and salt-away after every flight. I know it will only slow the corrosion, but this is too much fun. If it means I recover the airplane more often, so be it. They were never meant to last this long.
 
DENNY said:
I would not be surprised to find a break most anywhere in a factory 12 fuselage. I have seen a hard working 18 with a break between the gear fittings. Also happen to have a ski at that side with a big hunk of plastic missing!:oops: The plane is talking to you, time to listen!!! Suck it up, go to bare frame and sandblast. Replace tubes or fuselage as needed. Budget 30 grand and take a lot of tylenol because MOREBETTERFEVER will hit. OH YA how old is that gear???
DENNY
Click to expand...

30 grand? I assume that would be with a new fuselage and paying someone else to do the work. We took the wings and engine off yesterday and I'll have the fuselage apart in a few days.

The PA-18 extended gear is probably 20 years old. The extended gear were added some time after the main restoration in 1998.
 
Hope your corrosion is isolated. Seems like when you cut out all the bad on a 70+ year old fuselage there is about 60% airplane left. The last PA 12 I repaired had all the floor X bracing and most of the wing strut carry through full of rust. It all amounts to time versus money. New fuselage 15K or so. Pile of 4130 tubing to fix it, two to three hundred bucks.

Edit: I need to get out more. Sounds like I missed the cost of a replacement fuselage by about 10K by the time it gets to your door.
 
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Two of the most precious resources: money and time. You can change one for the other depending on what you have more of.

My dad spent 6 years rebuilding his PA-14, replacing every tube that had rust in it. He had about 20% of the original tubing left. By the time he finished that plane, the kids he planned to fill the two extra seats with were out of the house or busy with other things. I know he would have preferred to be flying it rather than welding on it.

Univair makes a new fuselage for the PA-12. It's $20k but it'll also save you a lot of time. https://www.univair.com/piper/piper...-000-univair-frame-assembly-fits-piper-pa-12/
 
I just looked at the PA12 fuselage drawing 24056 and the liner tube is in the longeron at the front gear fitting not the rear.
 
jadebons said:
30 grand? I assume that would be with a new fuselage and paying someone else to do the work. We took the wings and engine off yesterday and I'll have the fuselage apart in a few days.

The PA-18 extended gear is probably 20 years old. The extended gear were added some time after the main restoration in 1998.
Click to expand...

If you're hiring it out? I'd say you need to have at least $50K available. Seriously.
 
Crash said:
Two of the most precious resources: money and time. You can change one for the other depending on what you have more of.

My dad spent 6 years rebuilding his PA-14, replacing every tube that had rust in it. He had about 20% of the original tubing left. By the time he finished that plane, the kids he planned to fill the two extra seats with were out of the house or busy with other things. I know he would have preferred to be flying it rather than welding on it.

Univair makes a new fuselage for the PA-12. It's $20k but it'll also save you a lot of time. https://www.univair.com/piper/piper...-000-univair-frame-assembly-fits-piper-pa-12/
Click to expand...

FYI after the mods and shipping and crating you’ll be in the 24-26k range. But you have a brand new 4130 fuselage. We went that route with the restoration I’m working on now. When your paying someone to replace tubes it adds up quick, plus sand blast and prime, and you still have a 70+ year old fuselage.


Sent from my iPhone using Tapatalk
 
There is NO way I would repair that fuse. New is the only way to go in my opinion.
 
I gladly repair fuselages like that. I get paid by the hour. Some people are lazy and afraid to get their hands dirty.... it’s just some tubes. New fuselages weren’t an option for a long time. I have done some that at least half the tubes got replaced in front of the door and EVERYTHING behind the door.


Sent from my iPhone using SuperCub.Org
 
I trust in the predictability of what progressively happens with corrosion a lot more than I trust in the predictability of repair welds on a seriously corroded airframe. Just sayin'.

You were flying this plane recently. Think about that last flight or two! Get a new airframe.
 
Tennessee said:
I trust in the predictability of what progressively happens with corrosion a lot more than I trust in the predictability of repair welds on a seriously corroded airframe. Just sayin'.

You were flying this plane recently. Think about that last flight or two! Get a new airframe.
Click to expand...


Half the fleet is flying with repair welds and replaced tubing of some sort or another. Proper welding and tube replacement and its good as new. If you don't trust repair welds you must be dealing with a seriously inept mechanic
 
jadebons said:
30 grand? I assume that would be with a new fuselage and paying someone else to do the work. We took the wings and engine off yesterday and I'll have the fuselage apart in a few days.

The PA-18 extended gear is probably 20 years old. The extended gear were added some time after the main restoration in 1998.
Click to expand...


Yup takes a day or two to take it apart that’s the easy part.
I just went thru this, unless your a welder and have a lot of time, you’ll be ahead with a new fuselage. Mine was delivered a few weeks ago and I have no regrets. And the cost estimates of $30k for a cover job are accurate easily 300 hrs plus supplies. If you don't value your time at all, then it will be less....but that’s the starting point before you get to the might as well’s.... now I’ve got alum struts, pstol flaps, up gross, the list will go on. Ooh yah I’m an a&p, but one who knows his skill set. I chose to have one of the best Cub guys build mine. Good luck! It’s just money after all!
 
I'm still scratching my head at how/why those tubes broke in that area in front of strut (rear gear fittings) on floats....
 
akavidflyer said:
Half the fleet is flying with repair welds and replaced tubing of some sort or another. Proper welding and tube replacement and its good as new. If you don't trust repair welds you must be dealing with a seriously inept mechanic
Click to expand...

Trusting repair welds is one thing but it'll never be "good as new" if you've got half a dozen liner tubes, clamshell splices, and gobs of weld all over. Also, and this may come as a shock, there are far more inept mechanics than good ones out there in my experience. It's a testament to the basic design that some of the planes repaired by certain licensed A&P/IA mechanics are still flying.

It's a coin toss. With through and through cracks on the longerons like that, especially on a seaplane, there is a pretty solid chance of extensive corrosion. Your best bet is to strip the fuselage down, have it sand blasted, and look for pinholes. If it's going to be more than replacing a couple gear fittings and lower longerons then it's probably best to pull the trigger on a new fuselage to save yourself the headaches of doing repairs yourself or hiring someone and also to help with resale down the line.
 
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Some of us remember when Crash sr. did his 12.... I do, and when I needed similar work, I had one of the best cub frame welders do the jig work and welding on my cub. Man, when he pinned it in the jig, he was putting tape dots on tubes he'd replace or repair, and it was conservatively half of the fuse.... It IS a decent flyer now (never was before that), thanks Wayne, and Dave!

Fast forward 10 or so years, and a seriously wind damaged cub fell in my lap, and I remembered how Crash Sr.'s 12 went again.... I also remembered how his 18 - 180 went... (bought a new airframes fuse and sold the old junk....)

Sooo...This one got a new AF inc. fuse with help from Crash Jr, and I never looked back, and have no regrets.... You can make the old junk fly like a new one, but as Crash Jr. said, it still won't be the equivalent of a new fuse...

Some of us like tinkering.... some of us would rather be burning gas 8) ... There's no right or wrong in either, I have some of the skills, and ability to tinker, and most of the equipment, but would much prefer to hit the switch and fly.

YMMV...

Take care, Rob
 
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