epp and epoxy ?

In my experience with Zagis, the flexibility of the EPP foam is what makes them so durable. Epoxy will bond to EPP, but the expoxy and glass will likely be heavy and won't be flexible. The fiberglass tape with the packing tape over the top really is the way to go - although one sloper in our club did cover over the fiberglass tape with a low temp R/C film and it came out well. Just use VERY light dustings of the 3M Super 77 to stick the fiberglass tape and spars and you should be fine. Just to be on the safe side, make sure you test the adhesives you plan on using on some scrap EPP (like an outside corner of the wing bed) before putting it on your wing.

I think you would find that you will need a LOT of epoxy just to fill the holes in the EPP before you would get good adhesion of the cloth. It would end up making the wing a lot heavier. Also, the glass and epoxy would be a lot less flexibke and would fracture in the minor bumps and bashes that these wings get. EPP is the perfect material to survive this and the tape gives it just the right rigidity.

| In my experience with Zagis, the flexibility of the EPP foam is what makes | them so durable. Epoxy will bond to EPP, but the expoxy and glass will | likely be heavy and won't be flexible.

Right -- if you're going to fiberglass it, it'll be strong but fragile. Which is OK as long as you don't crash it, but that sort of defeats the purpose ...

| The fiberglass tape with the packing tape over the top really is the | way to go - although one sloper in our club did cover over the | fiberglass tape with a low temp R/C film and it came out well.

I do all my flying wings in Ultracote now. Looks much better, lasts longer and is a lot smoother. Really, the only downside is that it costs a little more.

There's a lot of web pages out there on modifications to make to your flying wings. Many (like Ultracote, buried control arms and the receiver under the battery rather than in front of it) are very well worth doing.

That's why I'd use micro slurry under the cloth. Micro slurry is epoxy mixed with several parts microscopic glass bubbles. Very light and strong. It's purpose is to fill the holes and bond to the cloth.

True enough. I measured it would add 100g to a 300g plane.

Here I have to disagree. I have a sample wing which is, although heavier, strong as steel. I can bang the leading edge on the edge of a brick and all it leaves is a smudge of brick. I can also drop a brick on it from eye level, point down, and all that happens is the brick bounces back up to belt level.

In any case, I will take your advice and favor lightness over strength. It does no good to make it strong if it can't fly.

Thanks, krb

Interesting. I think we all considered it at one point or another, and just concluded or assumed it would be too rigid to survive crashes. I wonder if it would be possible or worthwhile to carve out most or some of the foam after forming the 'glass. For that matter, maybe form the glass over balsa formers, and ... ;-P Well, that's a whole different realm of construction complexity. The real advantage of carved foam is its simplicity. You could build one entirely with just a hot wire and a kitchen knife.

I glassed up most of a picojet. It didn't add a lot of weight and did make it ding proof and snap resistant. And added enough rigidity to make it fly a little better.

The cloth sort of only sticks to the bumps - you don't end up with epoxy fulling the grain...and I used film over the top to make it look good.

If you are worried about that, get some lightweight filler and dilute with water and brush on, and sand first. That fills the hollows.

Finding the right amount of stengthening to still leave it bouncable is a bit of a trick. Use ine layer of thinnets first, and maybe another later in high stress areas..or a layer of thicker glass.