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Top wings uncovered

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airbiker

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Last night, my dad and I pulled the fabric and leading edges off of the top wing to get started on the aileron conversion. He's going to do some of the work on the top wing while I finish up the lowers at home. We'll tag team the bigger jobs when we can both get to the hangar.

There were a couple surprises when we got everything opened up. These are old Sparcraft wings. I was convinced that I had at least a couple nose ribs that were partially crushed or broken. Turns out all the ribs were in great shape and none showed any signs of damage. The corner blocks all look good at first blush. I think the loose nails holding the aluminum were wallowing around just enough to make some nose ribs feel spongy. Won't be an issue with the new ply leading edges.

The drag and anti-drag wires all sounded good and tight. None of the washers on the wires showed any signs of distress or starting to cup. I was expecting to see some problems here, but was pleasantly surprised to see things in good shape.

On the other hand, both diagonal tip braces had failed or improper glue joints at the rear spar. One pulled a little wood with the glue, but almost looked like it was glued over the varnish and the varnish is what pulled off the wood. The other joint broke on the glue line with Weldwood glue left on both surfaces. I don't think either joint turned loose until we saw the bad joints and tugged on them a bit. It took very little force to fail the joints. I've been pulling parts off the lower wings for the conversion and have gained a great deal of respect for Weldwood. These two joints were nothing like everything else I've seen.

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My dad also spotted a possible failure starting on one of the flying wires. It was just inside of the leading edge sheeting and wouldn't have been seen from the outside unless you knew exactly where to look with a flashlight. It looks like a very fine crack starting on one edge. It's barely enough to catch a fingernail. I tried to get some pictures, but it wasn't visible in any of them. The other wires looked good, but this one will be getting replaced.

The existing diagonal brace will get completely replaced with the square tips, so it's not really an issue. The flying wire won't cost any time, but will be another thing to help drain the remaining color out of my credit card.

Ian


 

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