Sig Fiberglass Cloth Regular Weight

[Paul Taylor]

When putting foam wings together do you use Regular weight or light weight fiberglass cloth?
My guess is Light.

[Andrew Borgogna]

Funny you should ask, I have a foam wing with glass tape curing right now.  Go to Aerospace Composite Products and get their 2" fiberglass tape.  I have built a lot of foam core wings and this is a good product for what you want.  I recommend the 2" for .40 size planes but they offer several sizes. 

http://www.acpsales.com/r several sizes. 

See my "Profile Nobler" posting for a picture of my wing with the glass tape curing.
Andy

[Paul Taylor]

Thanks Andy,
Sent you a PM.

 

[Steve Helmick]

You do need to take that "r" off the end of the url, to make the link work.

I'd still like to know the 'weight' of the FG. I think 2 oz would be minimal, and the .6 and .75 oz stuff would be about useless? Crist should have good data on this question! Yo, Crist!!!!!!!!!!      Steve

[Mark Scarborough]

FWIW, if you think in terms of balancing the stucture, how strong is balsa in comparison to glass cloth? even .74 cloth in the proper matrix is stronger than 1/8 balsa, at least in shear which is what we are putting it in. When joining a wing, the load on the cloth is from tip to tip, or shear loaded. it doesnt take much. All you are really trying to accomplish is to make a smooth flow of the stress from one panel to the other. having a single thick tape in some ways is actually a bad thing as it causes a stress spike to build right at the edge of the tape. What I do is to use .75 cloth, but I use 3 or 4 layers that taper, the first layer is only about an inch wide, then the second an inch wider, and the third slightly wider yet. This blends the strenght of the patch allowing stressees to be distributed smoothly across the joint.
my two cents worth.
Steve, the Q ship that I stuffed in Portland had two cuts through the bottom of the wing to add dihedral, I used two layers of .75 cloth  to bridge the splice area. The wing was the only part that didnt sustain damage. The paint didnt even crack.

[Greg L Bahrman]

I do it similar to the way Mark does it. My first layer is anywhere from 1 inch to 2 inch wide top and bottom. The second layer is cut in the shape of a football. The ends of the football are located at the leading edge and the trailing edge and it's maybe 6 inches wide in the middle. I use 1/2 oz. glass and it's plenty strong enough. Any more than that and your just adding unnecessary weight. I have crash tested it. If the wing has a spar in it then it will only need to have the silkspan or polyspan overlaped approx. 5 inches at the center top and bottom.

[Andrew Borgogna]

From the looks of the cloth I am using I would guess it is 2oz cloth.  One 2 inch strip is more than strong enough.  To feather it out in the past I use autobody glazing compound spread thing over the fiberglass and out onto the wing.  Then with some fine sand paper I feather it in.  This has worked well in the past for me, I am sure there are a hundred different ways to deal with the edge the fiberglass creates and if it is enclosed in a fuselage who cares.
Andy