Fiberglass vs. Fabric

Lou wrote:
What you described is what my plans call for. Wooden ribs with plywood
over but
routed inbetween. Then on top of the plywood I'm to install the fabric.
This is just one
of the areas that I want to replace the fabric with fiberglass. It is
obcviously not structural.
So replacing with fiberglass should give me a smoother, harder finish.
Also, I would like to know if this finish will give me a better gph for
trips not to mention maybe, just maybe a few more knots. Yes I would
love to talk to your friend.
Lou

Ahh so the fabric is to be a non structural skin over open bays like any
normal fabric covering. If you apply a rigid glass/epoxy skin it will
be the same as skinning the entire wing in plywood.

The ply is routed out between the ribs to save weight in an area where
the ply provides no structural benefit. If you want to create a rigid
glass/epoxy skin over an area that is normally covered with flexible
fabric it will have to be stiff enough to support air loads without
deforming. It will be much heavier than a fabric layer would be.

You might as well skin the entire wing in ply and use a minimal glass
layer as a protective coating. Either way you are going to end up with
a much heavier wing.

A rigid skin in the area aft of the spars designed for open bays with
flexible fabric will make no significant difference in speed if the a/c
goes under 150 mph, and it will cost you many pounds in weight.

Use a polyurethane covering process on those areas intended for fabric
over open bays. Only use glass/epoxy only on fully skinned components.


John