BTE Flyin' King kit...

Last night I tacked my top LE sheeting on the center section of the wing. It fit perfectly. I put Titebond on the top of the ribs, rolled the sheeting back, tacked the back edge down onto the spar and checked everything. Still perfect. This morning I get up to check on it, and the sheeting had pulled off of one of the ribs, leaving a nice lump where it should be smooth, and there is about a 1/16 gap on a 8" or so section where the sheeting meets the leading edge. The detached sheeting is the real problem. I can fill in the small gap between the sheeting and LE.

The question is this: how do I fix the sheeting where it came up off the rib? I can't push it back down because apparently when the sheeting pulled off, it pulled the glue too, which formed a nice little "bridge" of sorts, preventing me from reattaching it or pulling it up even more. In a sense, the glue filled the space between the sheeting and the rib where it pulled off. It's far enough up that sanding it down will not work.

Any advice? I'd hate to have to order a new center section.

Basically, you will have to cut the sheeting on both sides of the rib where the sheeting is elevated and then carefully remove the elevated sheeting and also remove the glue so that the surface of the rib is back at the correct level. Then cut out a piece of sheeting that will fit well into the gap/hole where the removed sheeting was. When glueing in the new piece you will probably do best by putting a piece of balsa sheeting under the splice line on both sides; glue the splice under the ends of the existing sheeting first. This will help to make everything even. Using medium CA for this job may be a good idea. Fill in any gaps with your favorite filler, then sand even and you're ready to cover.

What touch and go said is about the best way. Also, when using very slow cure glues, like tightbond, I always moisten the outside of the sheeting with water in a spray bottle, so that it becomes more pliant. This allows the sheeting to flex with less springyness. I also cut the sheeting overly large so I can put pins in at angles on both sides of the ribs. If you are about 3/4 to 1 inch longer than needed on both sides of the plank, you can cut and sand the planking so that you leave small curves where the center planking joins the leading and trailing edge planking.

I have gone to planking with thick or medium CA, that has been stored in the fridge, so it has a longer cure time. It allows the building process to go so much faster and lighter than tight bond or many of the other resin glues. You may want to consider using medium CA for your bulsa joiners, under your cut out area. If the area is large enough to get your finger under each joiner piece you can make the repair very quickly. Just don't glue your finger to the joiner, like I have done a few times, because I used too much glue.

Good luck with this somewhat frustrating repair!!

Mike Boyd

Let me add to what MikeBoyd said. I too build with wood glue (Elmer's Carpenter's Glue), and yes you need to wet the sheeting before you apply it. But you don't have to stop at just spraying it. You can totally soak the wood if need. I usually take the sheeting to the bathroom and run it under the faucet of the bathtub to wet it. You'll need to do this more so on harder brittle balsa. When you wet the wood like this make sure that the wood has dried before you remove whatever you used to hold it in place while the glue dried.

Ken

Here's a link to a "How To" for sheeting repair that will help you out:

http://www.rcuniverse.com/magazine/a...?article_id=98

Thanks for the advice and link. That how-to is something I have done on past models years ago, and was just hoping to avoid going through all of that. It has always been a MAJOR hassle to get the airfoil back to the original and intended shape with that method. At least for me.

I did wet the sheeting. It would have cracked had I not.

As I said, I was hoping I would not have to cut the sheeting. It's a pain to get the same airfoil on the repaired section. *sigh* Better than having to buy a new center wing kit though.

I think I'll finish up the top of the wing, then worry about the repair before I put the bottom sheeting on. I have a feeling it's going to be something of a hassle, but at least I used a wood glue here instead of CA. It'll be easier to sand back down to the original shape.

Any advice on getting this section of sheeting, both the repaired part and the original part, back to the same airfoil shape as the rest of the wing? When I cut the center part out the sheeting between the rib and the next rib is going to be very difficult to shape correctly.

RVM,
If you follow the how-to it shows you to add a "lip" around the edge of the existing sheeting. If you glue a piece of balsa under the good sheeting to make a lip that follows the shape of the airfoil, then when you glue in your repair piece it too will follow the curve of the airfoil.

Ken

Yes I know, but the sheeting around the goofed up area is also bowed up. I would have to pull sheeting off of three ribs to keep the right shape. There is a gap between the sheeting and the LE which prevents me from setting the shape.

Though, now that I think of it, I could put some balsa supports under it, which I'd have to do anyway to get a good fill, and glue the sheeting into the right shape. Then I could cut out the bad spot and hopefully fix things.

Hmm...

[&:]

Before you go hacking it up, try a very hot monokote iron on the raised part. You might get lucky with the heat melting the Titebond, and allowing the sheeting to lay flat.

Hmm really? I've got a 21st Century sealing iron. I wonder if it'll get hot enough through the sheeting.

Have you ever done this?

Thanks for the tip!

Yes! Also, this is the desired method of laminate manufacturers. They let the alphetic dry on both the laminate and the substrate, press them together, heat em up, and bingo, instant adhesion.

I have also read on these forums that some guys perfer this method for sheeting built up wings. Apply the glue to both surfaces, and iron the sheeting into place. Give it a try, and keep the iron HOT. Work slowly, especially where the lump is involved. More glue will probably take a little more time to melt. Good luck, and let us know how it turns out.

Thanks for the advice! I think I'll try this.

What did you end up having to fix using this method?

A buckle in the top sheeting on my TF 182. Worked really well.