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Old 04-21-2017, 11:37 AM   #26
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...since everyone is talking about the steen wing attach brackets - where can I buy them? I can't find them anywhere.

Thank you guys!


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Old 04-21-2017, 01:00 PM   #27
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I was trying my hand at a little sarcasm. But I would use them.


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Old 04-21-2017, 01:58 PM   #28
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Obviously my fault. Reading it the second time it is perfectly clear.

...don't forget all the weight I could safe without all the heavy welds.
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Old 04-21-2017, 04:15 PM   #29
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Simon
Your are right,build a jig before cutting the tubes is a good idea
So,with the 7/8" longerons,you should have a much stronger fuselage.
Don't have to many tubes on the rear of the fuselage;it will start to get heavy.
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Old 04-21-2017, 04:19 PM   #30
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Simon
For your wings attach brackets ,may be you can contact Aerographic
http://www.aerographic.com/laser_cut_parts.htm
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Old 04-21-2017, 06:52 PM   #31
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You could start over and have a nice new correct fuselage for your nice wings for less effort than you are facing trying to fix this one.
Reality check.
Someone had to say it, no offense intended just my 2
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Old 04-21-2017, 07:41 PM   #32
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Simon
Did you figure the cost of all tubes to build a new fuselage ?
I am totaly agreed with Rob.Not more work than fix the one you have and no jig to build
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Old 04-21-2017, 08:55 PM   #33
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Quote:
Originally Posted by crankyklingon View Post
You could start over and have a nice new correct fuselage for your nice wings for less effort than you are facing trying to fix this one.
Reality check.
Someone had to say it, no offense intended just my 2
Simon,

If you are using external sleeves of 7/8" tube you really need to use 0.058" wall thickness, otherwise the tubes rattle around on the 3/4" tube and there are big gaps to fill. That is not a weight penalty I would be prepared to wear…...

You also need far longer than 15-20 mm stubs because the idea of that repair method is to slide the sleeve far enough along one stub so as to clear the mating stub and then slide it back into place with sufficient "overlap" at both ends. And 20 mm isn't enough for the overlap and fish-mouth per AC43-13.1 anyway. Also an amount of "springing" is usually required, no small feat on the Pitts fuse with it's short bays, but a 20 mm stub isn't going to spring!

I once saw a Cub fuse frame where they'd replaced the entire longeron in the fashion you describe except using the internal splices, because the repairer was either too lazy or lacked the competence to cut out the longeron from the clusters. It looked terrible!

It takes about 30 - 40 minutes to grind the longeron out of a cluster, or you can make up some tooling using a hole saw or Rotabroach to do a more surgical job with about the same time input.

It requires a different and dare I say, higher level skill set to carry out repairs than to build things from scratch. Cranky's advice is the best offered yet.

Andrew.
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Old 04-22-2017, 01:13 PM   #34
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Doing a new fuselage from scratch will allow you to use a 7/8" x.035"
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Old 04-24-2017, 07:13 AM   #35
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Thank you guys for your honest opinion!

I'm not going to build a jig - I'm simply building adjustable, boltable braces that i bolt into the fuselage before cutting out a tube. After tacking the new tube in place the brace can be removed.

I only have to renew about 6 meters of tubing, a complete fuselage requires about 50 meters of tubing, some streamline tube, somit fittings here, some fittings there - I would easily end up spending 10 times the money for building a new fuselage. Since I'm not allowed to do the structural welding by myself I would have to pay someone to do it this will end up quite expensive.

I also don't want to weld the new tubing to the old one, I just want to have a rough alignment for the new tube before welding it to the junction. The tube will be welded to the existing junction point, not to the tube of course.

Summed up I simply don't get the point where building a new fuselage makes more sense than to simple change the damaged tubes from the really great fuselage?

@Jean-Luc: Thanks for the hint with aerografic, will shoot them a mail!
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Old 04-24-2017, 07:48 AM   #36
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Building a jig sounds good but are your sure it is a good straight fuselage to begin with.
I am with the other guys in start over and build a new fuselage and use the acceptable parts from the old one. Wonder if the builder drilled 1/8 holes in the tubing before welding tubes together so the oil inside the tubes get to flow in every tube.
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Old 04-24-2017, 08:31 AM   #37
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Again: This is one of only 8 or 9 factory fuselages - all welds (except for the ones done by the pre pre owner) are of excellent quality! So what would be the difference between building a new fuselage and using parts of the old one and salvaging the existing fuselage by only changing a few tubes?!

While cutting out some of the tubes I will be able to have a good look at the inside of the existing tubes.
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Old 04-26-2017, 01:49 PM   #38
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Great to see the progress on this, I nearly pulled the trigger on the purchase of this project. Good luck with it and watching with interest.
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Old 04-26-2017, 06:06 PM   #39
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Snap, I'm far from a an expert, but reusing the good sounds like the way to go. I have taken that tack from time to time myself. In your case due to the added cost I can see where your decision makes sense. And that opinion is worth every electron you paid for it.
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Old 04-26-2017, 08:10 PM   #40
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Simon,i hope to see very soon your fuselage done


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