All Carbon Wing-how to make?

[sayno2glo]

Hi,
I really like the construction of Elita http://rc-sailplane.com/elita/elita_e.htm
but don't know how it would be easiest to mold the carbon zig zag inside the wing. I would use this construction for F5D plane which is allot smaller. I think this method works better in smaller wings because there is less unsupported area in the skin.
I see lots of advantages in this construction like:

-does not get dings and dents.
-easy to mold and get right amount of epoxy because there is no core material absorbing epoxy.
-easy to join if the zig zag is molded accurately
-very stiff.

I would like to get some ideas how to mold the innards. How to get some pressure to the fibers while curing and get excess epoxy away. My idea is to mold some silicone triangles which are placed inside the wing mold and when heated they expand and squeezes excess epoxy away. :rolleyes:
Thanks,
/Antti

[SoarNeck]

Please let me know if you find out. I've been looking ever since this model first came out, and I think it's pretty-much a trade secret right now.

[sayno2glo]

Lets put the photo toohttp://rc-sailplane.com/elita/elita_wing_small.jpg

[SoarNeck]

I think the technique is called "wave-technologie" (yes, French) by most publications.

[jonferran]

Take a positive of the wing, cut it lengthwise into the zig zag sections, shave down the skin side of the positive to the thickness of the carbon. lay the cabon down section by section then lay the skin on and let the whole thing cure in the mold. If I had a wing mold and a positive I'd try it :P

Jon

[davidfee]

That's "easy." You just need another mold to make the zig-zag part. Sandwich the laminate with peel-ply on both side for bonding to the upper and lower skins. Bag it to press the laminate against the form. No problem. The hard part would be the mold... CNC would be the best way to do it, I think.

-David

[sayno2glo]

Hi,
Thanks for your quick replies. I like the combination of Jon's and David's suggestion which would be forming epoxy wing, sawing it to zig zag and then bag the carbon with peel-ply in it.
I just rethought this and it would require about 6oz of carbon in the skin not to be too soft. This means there would not be weight saving compared to normal sandwich wing, but all other good things will remain.
/Antti

[Tony D.]

Check this out:

http://www.favonius.com/soaring/index.htm

Go to the Old Pages link and click on Estrella.

It is the Estrella and I think it may have been the first commercial glider to use this technique. It looks like the manufacturer used +/-45 degree cabon sleve (sock) inside the wing.

I have often thought of trying this, it would not be that difficult to anchor the carbon sock to the surfaces.


T.D.

[marcwv]

Other than now needing a positive mold ,I not sure from this thread what the advantage is in using this zig-zag technique

[davidfee]

With that many shear webs and such well-supported skin, bending and torsional stiffness should be fantastic.

-David