Kitfox iv wing repair

[Dusty]

I am in a position of needing to repair my port wing on a model 4 1200 damaged in an engine failure, ditching event
The good folks at kitfox can supply the parts, 2 spars /inserts and aileron etc.
We intend to remove the Spars and insert the new ones. Preference would be for a quick build wing but the freight to New Zealand for such a large item is eye watering.
Any hints and suggestions for spar replacement welcome.
I will also inquire about replacing both my ailerons with the later asymmetric style vs the symmetrical it currently has. Has anyone done this and is there any benefit to be had.
Cheers
Dusty

[taff]

I'm thinking a small wood chisel to get the bulk of the adhesive off and then thread a wire (safety wire) to slowly cut through between the rib and the aluminum?
Use it like tooth floss.

How about the fuel tank? This is going to be a tough one.
What is the adhesive holding that in. If it's the soft rubbery stuff, maybe the wire to slowly saw through this?
Are you going to order ribs as well?

[avidflyer]

The spars are 6160 2 1/2" OD aluminum tube with a .065" thick wall. I would think that could be bought in NZ or Australia. To get the spar and wood ribs seperated, I would imagine it would be best to cut the spars in pieces, so you are only dealing with one rib at a time. If you only have a 1" long piece of spar in the rib, you should be able to cut it in quarters and peal it off of the epoxy with some heat applied to the aluminum. Then use a dremmel or similar cutter to remove the epoxy. Front spar will come off easier, but I can't imagine pulling out the rear spar in one piece. And if you are replacing it anyway, it must be junk.... JImChuk

[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.

[jiott]

I second Eddie's comment.

[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.

[taff]

I remember;
Installing the I beams inside the wing spars. The instructions made sure that no rough contaminate (grit and stuff) entered the spar when sliding the I beam into the opening.
For fear of damaging the aluminum, causing stresses.

If you drill to remove the rivets, there would be so much burr that trying to tap and push the I beams out would be about impossible.

I second the others and suggest the full monty, in bits to save on package size. Would it save on freight ?

If you don't have the instructions and drawings on assembly, you will need them.

[Dusty]

Thanks for the replies
I assume hysol (1994 kit) ,chopping the Spars individually and replacing one at a time may be an option. I will get 2 spars and inserts from kitfox.
My rear spar maybe OK we wont know untill the bent front spar is removed or temporarily straightened.

Any specialist aluminum has to come from overseas and I am happy to support kitfox.
My aileron doesn't look right so will be replaced and the Spars can be boxed together.

The wreck has just been released by my insurance so I am still assesing.
I will get a price for ribs etc if cutting doesn't look feasable

Any ideas on using the later style ailerons?

[DesertFox4]

Dusty, Per the New style flapperons, I’d stay with the symmetrical ones. They should preserve your lighter feel and quicker roll rate.
First time I flew the asymmetrical flapperons, I really noticed the higher control loading in the roll axis especially after years in the model 4s.
Now, after years in the newer models, I’ve become accustomed to the feel of the asymmetrical flapperons and have zero complaints.
Just not quite as “sporty” in roll.