Bringing a Model 1 back to life

[avidflyer]

As long as you cut the fabric up that much, I would rip it all off. Kitfox wings are real easy to do. Everything is straight on them. Lots more work on an Avid with the rounded wingtips., If you do a good glue job, there is really no need to rib stich on these old slower planes either if you ask me. Then while you have the wing apart, you could install at least one fiberglass wing tank as well. JImChuk


PS forgot the false ribs question. I would make my own. I've done it before quite easily. You do want to use the right plywood though. 1/8" 5 ply. https://www.aircraftspruce.com/catal...nnishbirch.php
I may even have some of the false ribs here. In fact, now that I think about it, I do.

[Good old number 29]

I just wrote a good long post, then got logged out before it posted. Okay, I skinned it, and have no regrets. It was pretty solid, but there was some oxidation on both leading edges where the fabric was attached. None on the rear spars. The left wing was worse, and ten false ribs came loose, at least partially, from the front spar, besides the two I pulled off, earlier. On the right wing, one false rib had broken, and only one other came loose from the spar. They were all well attached to the wood stringer. Ribs look good. Time to order those wing tanks. Maybe they’ll do better than twelve weeks if I order two of them now. I think I’ll go for the thirteen gallon tanks. I’m considering coating the front spars with epoxy, to prevent further corrosion where the fabric holds moisture against it. Any thoughts on that?

[David47]

..... I’m considering coating the front spars with epoxy, to prevent further corrosion where the fabric holds moisture against it. Any thoughts on that?

Always a good idea to prime aluminium with a two part epoxy primer. On the subject of the fabric retaining water, if the fabric has been treated correctly with all finishing coats you shouldn't be getting water retention. Regardless, I'd recommend epoxy prime the spar.

[avidflyer]

Ouch. I'm not a metal specialist or anything, but corrosion on a spar seems pretty scary. Are your spars just round tubes, or do they have a verticle section going down the center? Here is a picture showing the type with the verticle stiffener. I would think these are stronger, and would maybe be less worried about them then the regular round tubes. JImChuk

PS. I guess I couldn't up load the picture

[Good old number 29]

The spars on the model 1 are reinforced with Z-metal, rather than the extruded I-beams of later models. You can kind of see it in the pic. The light spot is light shining in the other end of the spar. Hard to get a good picture of the middle of the spar. That is a partial length reinforcement. The Model 2 used a full length I-beam, and Model 3 went back to a short section, but lengethened the lift struts. I posted pictures of the description of model improvements and gross weight increases from Model 1 to Model IV 1200. Hopefully the pics are readable. It’s good info.

[Good old number 29]

I think the coatings were good. It could have gotten moisture in from the holes on top, but they were taped up pretty good. Also, if it was water coming in a hole, the spot nearest the hole would be worse than the rest. You can see the wavy line of oxidation where the fabric of the underside of the wing was wrapped up around the spar. It seems evident that either the fabric was wicking moisture, or the cement had corrosive properties. Since the cement was on other areas that did not seem affected by corrosion, I’m ruling that out. Also, there has to be a reason that the left wing was worse than the right. I’m pretty sure it’s from condensation. The wings heat up a lot in the sun. I could feel the heat coming out of the hole in the wing, yesterday, with the sun shining on part of it. Hot air holds much more moisture than cold air. So, on a cold day, that hot air is sucking up moisture like a dry sponge. Then, when the sun goes down, there isn’t enough air flow to evacuate the moisture from the wings, and it condenses on the bottom of the inside of the wing. The reason the left wing is worse, is because it wasn’t sealed up as tightly, allowing more moist air to enter the wing. It has that unusual storage compartment with the open end and short ribs and slats of plywood holding the fabric out, allowing airflow to the rest of the wing.

[efwd]

I suppose that is the photo that will explain the answer to the frequently posted question. Should I epoxy primer the spars?