Fiberglass vs. Fabric

Well, maybe no sense right away, but the plans where drawn quite a
while ago. Like the Emeraude, the invention of fiberglass hadn't
arrived yet. Although I agree with the statement of making it as light
as possible, one of the reason's for this post is to discuss weight.
If this can be done with little or no weight penalty, then I thought I
would consider the experimental part of this group. After all, if Tony
Bingelis did it with good results, then why not consider it? I like the
idea of smoother, flatter, and more solid wings. If it turns out to be
25lbs or more, then I have to re-think this or just consider going on a
diet.
Lou

If you are building an Emeraude, you must have really good taste! That is
one beautiful
aircraft. My advice is if you are completely covering the wing with
plywood - then put on a lightweight covering of fibreglas and West epoxy. If
you are going the partial sheeted, cap strip, open bay route - stick with a
light dacron (heat shrunk) covering system like SuperFlite or something
similar.. it will look nice! Just be sure to follow the manufacturers
instructions procedure/temperature-wise.

Dave
Wittman W10 Tailwind builder

"Lou" wrote in message
ps.com...
Well, maybe no sense right away, but the plans where drawn quite a
while ago. Like the Emeraude, the invention of fiberglass hadn't
arrived yet. Although I agree with the statement of making it as light
as possible, one of the reason's for this post is to discuss weight.
If this can be done with little or no weight penalty, then I thought I
would consider the experimental part of this group. After all, if Tony
Bingelis did it with good results, then why not consider it? I like the
idea of smoother, flatter, and more solid wings. If it turns out to be
25lbs or more, then I have to re-think this or just consider going on a
diet.
Lou

"Lou" wrote in message
ps.com...
Well, maybe no sense right away, but the plans where drawn quite a
while ago. Like the Emeraude, the invention of fiberglass hadn't
arrived yet. Although I agree with the statement of making it as light
as possible, one of the reason's for this post is to discuss weight.
If this can be done with little or no weight penalty, then I thought I
would consider the experimental part of this group. After all, if Tony
Bingelis did it with good results, then why not consider it? I like the
idea of smoother, flatter, and more solid wings. If it turns out to be
25lbs or more, then I have to re-think this or just consider going on a
diet.

I understand where you're coming from, Lou - having had the same dilemma
myself while building the Emeraude. Fortunately we have a good builder
support group who could advise me on the nuances of that particular design.

Covering a wing with plywood that was originally designed for fabric and
open bays, will do more than change the appearance. An aircraft designer has
planned for the weight distribution (hence stress distribution) across the
span and chord. Skinning the wing will change both of those. You may
actually end up with a wing that is heavier, weaker and slower than before.
Do not make these design changes casually. Orville and Wilbur were
successful due to engineering, not trial and error.

First, ask yourself "What am I intending to accomplish by doing this?" Any
change requires more build time and usually more money. There can be other
penalties as well. If you're into engineering and test piloting as a hobby,
knock yourself out. It's your time, money and neck.

Re-engineering an older design can have no limit. Look at the fiberglass
version of the Beech 17 Staggerwing as an example. If you contemplate
changing a fabric wing to a skinned wing, why not go carbon fiber? How about
Nanotubes? Keep the end goal in sight.

Good Luck with your project!

Rich

P.S. The CAP-10C, the newest version of the Emeraude, now has a carbon fiber
spar.

Ron Webb wrote:
Probably coating the entire plywood covered wing, inside and out with
cladding epoxy would eliminate the changes brought on by humidity
variations.

In furniture making it is considered important to finish both sides
of a piece of wood the same to maximize dimentional stability.
Otherwise the rate at which moisture enters or leaves one side
of the board is different from the other so that whenever there
is a rapid change in humidity one side swells more than the other.

IOW, I tend to agree with the statement above, but the same
would be true for varnish, shellac, paint etc, so long as it was
the same inside and out, and the wing was vented so that the
humidity inside the wing was the same as outside.

Of course the sun only shines on (and dries) the outside.



You may be familiar with "Wood/Epoxy Saturation Technique"
That has been used in boat building for decades?

How about "WEST systems" epoxy?

Yep - that's where the "WEST" in WEST systems comes from.

The wood gets soaked all the way through, so the wood is just there for
support, and it seems to last forever.

Hve you tried cutting through a sample? My understanding is that the
epoxy will not penetrate any deeper than 1/16" through side grain,
and it would be VERY unlikely to penetrate past the glue beneath
the surface veneer in plywood. It woudl penetrate farther up the
endgrain, but since epoxy hardens pretty fast I doubt it would get
very fat that way either. You can saturate a board with linseed oil,
or mos taly oil, by leaving one end in a bowl of oil overnight.

I BOILED some samples for 24 hours with no degradation other than a bit of
color change. Add light fiberglass over that...

Did you compare bending strength before and after? What is the
glass transition temperature for WEST system epoxy?

No question that it's good stuff, but it's not magic.

---

FF

Rich S. wrote:
"Lou" wrote in message
ps.com...

Well, maybe no sense right away, but the plans where drawn quite a
while ago. Like the Emeraude, the invention of fiberglass hadn't
arrived yet. Although I agree with the statement of making it as light
as possible, one of the reason's for this post is to discuss weight.
If this can be done with little or no weight penalty, then I thought I
would consider the experimental part of this group. After all, if Tony
Bingelis did it with good results, then why not consider it? I like the
idea of smoother, flatter, and more solid wings. If it turns out to be
25lbs or more, then I have to re-think this or just consider going on a
diet.


I understand where you're coming from, Lou - having had the same dilemma
myself while building the Emeraude. Fortunately we have a good builder
support group who could advise me on the nuances of that particular design.

Covering a wing with plywood that was originally designed for fabric and
open bays, will do more than change the appearance. An aircraft designer has
planned for the weight distribution (hence stress distribution) across the
span and chord. Skinning the wing will change both of those. You may
actually end up with a wing that is heavier, weaker and slower than before.
Do not make these design changes casually. Orville and Wilbur were
successful due to engineering, not trial and error.

First, ask yourself "What am I intending to accomplish by doing this?" Any
change requires more build time and usually more money. There can be other
penalties as well. If you're into engineering and test piloting as a hobby,
knock yourself out. It's your time, money and neck.

Re-engineering an older design can have no limit. Look at the fiberglass
version of the Beech 17 Staggerwing as an example. If you contemplate
changing a fabric wing to a skinned wing, why not go carbon fiber? How about
Nanotubes? Keep the end goal in sight.

Good Luck with your project!

Rich

P.S. The CAP-10C, the newest version of the Emeraude, now has a carbon fiber
spar.


Does it use that "pulltruded" carbon rod stuff for caps? That stuff is
incredibly strong, far superior to carbon roving in compression and tension.

John

Applying glass over ply skins results in a solid base for a
beautiful finish. Agree about the peel ply for sure.

The inside of the plywood should be sealed. Take a look at System
Three Clear Coat. Pure epoxy, water thin, first coat soaks in a lot.
Two coats does a nice job sealing plywood. Compatable with T-88 even
as a wet coat. In other words, you can paint the second layer of
ClearCoat on the ply skin, apply T-88 to rib caps, and bond
immediately. The other way is to squeege T-88 on to the ply. I guess
any epoxy might work as a sealer, but I like compatability at the rib
line bonds.

Dan Horton

I BOILED some samples for 24 hours with no degradation other than a bit
of
color change. Add light fiberglass over that...

Did you compare bending strength before and after? What is the
glass transition temperature for WEST system epoxy?


Well, actually I made up a long sample with 2 1" wide strips glued (with
fillet) together at a 90 degree angle. Then
I cut this into samples, each about 1" long. Then I took these little "T"
shaped samples, and subjected them to all sorts of things.

They were made of Finnish Birch 3 ply (3mm thick, but quite dense.) It
looked like it had penetrated to me - and they sure stayed together fine. I
boiled several of them, and broke them afterward. The wood gave before the
glue in all cases.

I've also tried this with 1/8" Okume. Same result, but that stuff is porous
enough that I'm pretty sure it soaks all the way through. I've been meaning
to try it with that unfinished mahogany indoor plywood. If that "soaks all
the way through" stuff works, it would be usable as a core, so I could use
much cheaper material (for boats at least).

As for the glass transition temperature, I think most epoxies are in the
140F range. After they cool they will return to much the same condition they
were before though. The extra cure may even be beneficial. That's just a
dull memory though. Correct me if I need it, but the boiled samples really
did stand up fine (I'm looking at one now).

"J.Kahn" wrote in message
... Rich

P.S. The CAP-10C, the newest version of the Emeraude, now has a carbon
fiber spar.
Does it use that "pulltruded" carbon rod stuff for caps? That stuff is
incredibly strong, far superior to carbon roving in compression and
tension.

I don't know. The website of Mudry Aviation has disappeared and I think the
company has been sold. I haven't had occasion to look it up.

Rich S.

Ok, everyone, I've started to experiment with fiberglass. I bought the
foam, the fabric,hardner and resin. I've mix the resin and hardener
with micro balloons and came up with something that resembles honey
dijon salad dressing. I've put it on the foam, layed down the fabric
and then had to mix more resin and hardener. Put that mix on top and
spread it around. Layed down another layer of fabric, mixed more
resin/hardener, spead it around and layed down dacron.
Now the big question, Does this sound correct? Can anyone tell me if
I missed a step? This so far is a test piece, but I know what I can use
it for. I am kinda suprised of how flexable the fiished product is.
Lou

On 25 Jun 2006 03:53:58 -0700, "Lou" wrote:

Ok, everyone, I've started to experiment with fiberglass. I bought the
foam, the fabric,hardner and resin. I've mix the resin and hardener
with micro balloons and came up with something that resembles honey
dijon salad dressing. I've put it on the foam, layed down the fabric
and then had to mix more resin and hardener. Put that mix on top and
spread it around. Layed down another layer of fabric, mixed more
resin/hardener, spead it around and layed down dacron.
Now the big question, Does this sound correct? Can anyone tell me if
I missed a step? This so far is a test piece, but I know what I can use
it for. I am kinda suprised of how flexable the fiished product is.
Lou

nah you've got it totally wrong :-)
y' dont Fiish the bloody stuff you squeegee it out thin.
pretend it's a million dollars a litre and make it extend as far as
possible.
remember "not white, not wet"

forget how flexible it is until it cures.
how heavy is it?

Stealth (glad it's him not me) Pilot