Kitfox iv wing repair

[efwd]

I would seriously consider just ordering the wing kit. Your already getting spars. I think building a new wing from new parts will be so much less annoying than trying to salvage parts. Shipping should be much more reasonable with the ribs in a box vs. the assembled wing.

[alexM]

I know that with the wings on my Citabria it was technically possible to detach the ribs and slide the spars out. Although that is a gross oversimplification there are a lot of parts that can stay attached to each other in the process and it will still look like a wing sitting on the table.

I don't think you'll find the Kitfox wings to be the same at all. You can't get the ribs off without drilling out/de-bonding the drag/anti-drag tubes and at that point you're left with a pile of ribs held together by the trailing edge pieces.

Do you know when your wings were built? I ask because the adhesive used matters here.

My project came with new spars and internal extrusions. The plan of the previous builder, and the one I started with, was to get those ribs loose and re-use them on the new spars. You can get structural adhesive to let go with a heat gun or by sticking it in an oven if the part is small enough. I learned quickly that the old 3M structural adhesive needs WAY more heat to break loose than the EA9460 Hysol we use now. By the time the 3M stuff even started to give up the wood was starting to scorch. I quickly realized that by the time I perfected the technique I would have 100+ hours in salvaging ribs and I would still have lost some because they'd be burnt.

I had just typed up a part where I suggested chopping the spars near the ribs as someone else had suggested above. The long spars serve as a heat sink to draw heat away from where you're working, so by cutting the spars into short pieces you could toss the ribs into an oven one by one. Working carefully you'd have way less risk of burning the wood.

But that won't work because the rib cap strips are also bonded with structural adhesive! This stuff is thermoset resin so once it is heated to the stage it gets rubbery it does not recover. It's done. Finito. Even if the cap strips were retained by the staples and they "looked fine", the adhesive would be compromised. I've read where people say you can heat up structural adhesive to reposition a crooked part. That is mythology. Yes, you can reposition the part but the glue is permanently compromised and this is true of any two part adhesive. The only way you might get lucky here is if the ribs were made using the old 3M adhesive but the builder used EA9460 to assemble. You've got nothing to lose in testing a rib with a heat gun to see how it goes.

I'm going to suggest you do what I did and order new ribs. The shipping that is killing you is that long crate with the spars. A plan B might be to source the spar tubes locally and order the internal extrusions from Kitfox. That would be a 6' crate instead of 13'. The difference in shipping might pay for those ribs.

[Eric Page]

I'll second Alex's comment about the old 3M Scotch-Weld being impossible to remove. My Series 5 came with a dented elevator push-pull tube, so I needed to fabricate a new one. I tried to remove the machined end fittings from the old tube to re-use, but even with a propane torch the Scotch-Weld would not release. I boogered the fittings up so badly in the attempt that I ended up ordering new ones from Kitfox.

[efwd]

If I were to try this I would cut the spars into segments and try heating the spar from inside exclusively as to avoid burning the wood. My heat gun (Steinel) can be turned up to temps adequate for soldering, 1200F. Expensive but You will save a gob of time once your proper temp is determined to release the Hysol. Having a digital temp control makes putting Oratex on a much easier process, that is how I came into this gun.