Replace fabric with glass

Robert Little wrote:
With the superior strength of glass cloth, why not offer it in a litter
weight? A very good question that I asked the president of the Ultra Light
Aircraft Association. Because of the very expensive process of getting a
new product "certified" by the FAA, I had that organization do a survey for
interest in a permanent fabric. There was no interest at all. After many
years of instructing rib stitiching and fabric installation at the Oshkosh
EAAFly-In, the survey was not too surprizing.

We realize that we don't have to get the blessings of the FAA to sell to the
home builder and can sell "uncertified" fabric as the other companies do.
But unfortunately, that light-weight uncertifed fabric usually shows up on
certified aircraft, regardless of the regulations and recommendations. And
yes, wing loading, speed and flight regimen does mandate the different
weights of fabric. A good reference is the A.C. 43-13.1B.

So, until I think that I can sell enough of our 1.5 oz that test in at 92
lbs/ inch that will break even with the cost of certification, we will not
offer it to the public. (New Grade A cotton only tests at 80 lbs/inch)

The cost difference of glass fabric is 80% greater than polyester. But it
is glued with butyrate dope (no nitrate-laced glue), taunten with butyrate
dope, filled with non-tauntening butyrate dope and should be topped with
butyrate dope, although, the top coat is the installer's choice. We still
buy MIL SPEC butyrate dope for less than $16 a gal. I'll let you figure the
total cost of a cover job from these figures.

I hope that this has answered some of your questions. All things are based

You answered the questions, very good answers, in fact; however, it
doesn't help me. I hear you paraphrasing Ford. "You can have anything
you want, as long as it is what we sell." Which is OK, it just doesn't
help me any.

What I'm after is a 1) lighter elevon and 2) simpler to build elevon.
If it is stronger or cheaper, we can party on those points, too, but
they are secondary. Your process, while excellent, helps on neither point.

I don't mean to tell you your job here, but did you ever consider asking
the Ultralight Association if they would be interested in a LIGHTER
fabric. My impression of the ultralighters I know is that they look at
their planes as dirt bikes. They are not serious modes of
transportation, they're toys. Why would you EVER worry about a
permanent fabric on a toy! But if those guys think they can cruise 1mph
faster or climb 1fpm quicker they'll ransom their children for pixie
dust. I guess it is equally true for the GA crowd, and especially for
the tube'n'rag crowd. For the most part, tube'n'rag crafts are not
serious transportation; therefore, PERMANENT COVERING means zilch.

Now if you'd like to sell some 1.5oz cloth, I'd like to do some test
with substituting a standard epoxy for butyrate dope.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

On Wed, 14 Apr 2004 18:03:49 GMT, Ernest Christley
wrote:

You answered the questions, very good answers, in fact; however, it
doesn't help me. I hear you paraphrasing Ford. "You can have anything
you want, as long as it is what we sell." Which is OK, it just doesn't
help me any.

What I'm after is a 1) lighter elevon and 2) simpler to build elevon.
If it is stronger or cheaper, we can party on those points, too, but
they are secondary. Your process, while excellent, helps on neither point.

I don't mean to tell you your job here, but did you ever consider asking
the Ultralight Association if they would be interested in a LIGHTER
fabric. My impression of the ultralighters I know is that they look at
their planes as dirt bikes. They are not serious modes of
transportation, they're toys. Why would you EVER worry about a
permanent fabric on a toy! But if those guys think they can cruise 1mph
faster or climb 1fpm quicker they'll ransom their children for pixie
dust. I guess it is equally true for the GA crowd, and especially for
the tube'n'rag crowd. For the most part, tube'n'rag crafts are not
serious transportation; therefore, PERMANENT COVERING means zilch.

Now if you'd like to sell some 1.5oz cloth, I'd like to do some test
with substituting a standard epoxy for butyrate dope.

I'm building a rag and tube airplane and I sort of break the mold I
guess. I'm interested in outdoor storage, because it's a lot less
expensive, and I'm also interested in traveling places.

I won't go anywhere enormously fast, but I'll get there.

So a permanent fabric REALLY interests me.

Corky Scott

Question for the Razorback Fabric guy:

I'm currently finishing up the training for my A&P certificate at the
school here in Anchorage, and as it so happened, the lecture this
morning was about fabric covering. The instructor brought up Razorback
fabric, mentioned that it is great stuff, but then added that we don't
see much of it here in Alaska because it tends to sag in cold weather
compared to the shrunk-on polyester fabrics. As I recall from the
lecture, he said it was due more to contraction of the underlying
airframe in sub freezing temperatures, than any change in the fabric.
The heat shrunk fabrics apparently don't suffer as much from this
because there is enough extra tautness is added during the shrinking
process to make up for any dimensional change in the airframe at low
temperatures.

I was just wondering if you have any comments in this regard?

----------------------------------------------------
Del Rawlins-
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Del Rawlins wrote:

Question for the Razorback Fabric guy:

I'm currently finishing up the training for my A&P certificate at the
school here in Anchorage, and as it so happened, the lecture this
morning was about fabric covering. The instructor brought up Razorback
fabric, mentioned that it is great stuff, but then added that we don't
see much of it here in Alaska because it tends to sag in cold weather
compared to the shrunk-on polyester fabrics. As I recall from the
lecture, he said it was due more to contraction of the underlying
airframe in sub freezing temperatures, than any change in the fabric.
The heat shrunk fabrics apparently don't suffer as much from this
because there is enough extra tautness is added during the shrinking
process to make up for any dimensional change in the airframe at low
temperatures.

I was just wondering if you have any comments in this regard?

----------------------------------------------------
Del Rawlins-
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Just one. Thanks for passing that on to the group.

In actuality, we do sell quite a bit of fabric to the Northern reaches. ERA
has worn our fabric on their DC-3s and the military sure has used it on a
lot of cargo planes in the northern frontier over the years. We are always
sending out belly repair kits to Maules owners there, as well as a large
contigent of Stinson owners. It is plausible that there could be a problem
with improper installation or very poor conditions during istallation.
Cellulose Acetate Butryate dope is an organic laquer that is sensitive to
atmospheric conditions (usually needing 70 plus degrees of heat during the
application) but is usually very stable once it dries. Again, dope on cotton
and linen has been used for the 50 years prior to the introduction of the
newer fabrics.

I know that a cannon ball drop test was performed on our fabric at many
different sub temperatures and published. Nothing was printed about loss of
tautness due to temperature, only poor application due to following the
instructions. Even an aircraft manufacturer was repremanded for not
following the installation manual by not reinforcing the stress points over
longerons and formers (also as per the A.C. 43-13) with reinforcing tape.
They were saving time and labor by not doing so. The owners paid for the
time saving twenty to thirty years later.
"Del Rawlins" wrote in message
...
Question for the Razorback Fabric guy:

I'm currently finishing up the training for my A&P certificate at the
school here in Anchorage, and as it so happened, the lecture this
morning was about fabric covering. The instructor brought up Razorback
fabric, mentioned that it is great stuff, but then added that we don't
see much of it here in Alaska because it tends to sag in cold weather
compared to the shrunk-on polyester fabrics. As I recall from the
lecture, he said it was due more to contraction of the underlying
airframe in sub freezing temperatures, than any change in the fabric.
The heat shrunk fabrics apparently don't suffer as much from this
because there is enough extra tautness is added during the shrinking
process to make up for any dimensional change in the airframe at low
temperatures.

I was just wondering if you have any comments in this regard?

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

In Robert Little wrote:

very stable once it dries. Again, dope on cotton and linen has been
used for the 50 years prior to the introduction of the newer fabrics.

Yes, but both of those fabrics have built in shrinking ability and will
continue to shrink as they age. How can you make fiberglass cloth
shrink? Maybe I just don't understand enough about your process to get
it. Do you have a website with technical information, or could you post
an excerpt from the relevant part of your application manual?

----------------------------------------------------
Del Rawlins-
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Del Rawlins wrote:

In Robert Little wrote:

very stable once it dries. Again, dope on cotton and linen has been
used for the 50 years prior to the introduction of the newer fabrics.

Yes, but both of those fabrics have built in shrinking ability and will
continue to shrink as they age. How can you make fiberglass cloth
shrink? Maybe I just don't understand enough about your process to get
it. Do you have a website with technical information, or could you post
an excerpt from the relevant part of your application manual?

----------------------------------------------------
Del Rawlins-
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Del,

Check the model airplane supply houses.
You can find glass down to 1/2 ounce per yard.

Butyrate shrinks quite a bit.
Even the "non-taughtening" variety pulls up a bit.

So a glass skin would rely on the coating for taughtness
(not in the MS dictonary?) - just like linen does.

In Richard Lamb wrote:
Del Rawlins wrote:

In Robert Little wrote:

very stable once it dries. Again, dope on cotton and linen has been
used for the 50 years prior to the introduction of the newer
fabrics.

Yes, but both of those fabrics have built in shrinking ability and
will continue to shrink as they age. How can you make fiberglass
cloth shrink? Maybe I just don't understand enough about your
process to get it. Do you have a website with technical information,
or could you post an excerpt from the relevant part of your
application manual?

Del,

Check the model airplane supply houses.
You can find glass down to 1/2 ounce per yard.

I'm not sure what this has to do with the effects of cold weather on the
glass cloth. I think you are confusing me with Ernest.

Butyrate shrinks quite a bit.
Even the "non-taughtening" variety pulls up a bit.

So a glass skin would rely on the coating for taughtness
(not in the MS dictonary?) - just like linen does.

I thought that the natural fiber coverings like linen or cotton were
primarily shrunk using water? I.E. they get most of their tautness from
natural shrinkage as the water dries, prior to the coating being applied.
Or am I all wet? I don't know a lot about fabric covering and am just
trying to get a clear understanding of the various systems.

----------------------------------------------------
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"Del Rawlins" wrote in message
...
In Richard Lamb wrote:
Del Rawlins wrote:

Butyrate shrinks quite a bit.
Even the "non-taughtening" variety pulls up a bit.

So a glass skin would rely on the coating for taughtness
(not in the MS dictonary?) - just like linen does.

I thought that the natural fiber coverings like linen or cotton were
primarily shrunk using water? I.E. they get most of their tautness from
natural shrinkage as the water dries, prior to the coating being applied.
Or am I all wet? I don't know a lot about fabric covering and am just
trying to get a clear understanding of the various systems.

No, the water was just to take out the natural shrinkage of the fabric
before putting in the artificial tautening that occurs from either the
nitrate or butyrate dope. Either dope can tauten so much that with too much
application they can actually crush the airframe. The dope grabs hold of
each fiber and pulls the spaces between the fibers closer together. This is
the tautening action achieved with using dope whether it is cotton,
polyester or glass. And yes, you can find glass fabric in the model plane
catalogs that can acheive similar results.

We would be glad to send anyone our instruction manual for free if they will
just send us their snail-mail address. I hope that I've sparked som
interest in the alternatives available to the aircraft builders.

One other thing, though. The use of epoxy or polyester resin combined with
glass again starts the deterioration clock. The glass is permanent, but the
resins are what age so quickly in the presense of UV radiation. Old
fiberglass boats look rough after a few years and will burn like gasoline.
The glass does not age and will be the big mess left after the fire since it
does not burn. Our process doesn't use any resins as one usually assumes
when glass is mentioned. The "temporary cellulose" base dope is used to
fill and tauten only. It can burn off but the glass will remain in place
with little to no loss of strength to the fabric. The late Bill Hale always
used our fabric on his acrobatic aircraft due to the glass acting as a fire
wall to the occupant. Many NASA experimental windmill and wind tunnel
blades have been covered with our glass as well.
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Richard Lamb wrote:


Butyrate shrinks quite a bit.
Even the "non-taughtening" variety pulls up a bit.

So a glass skin would rely on the coating for taughtness
(not in the MS dictonary?) - just like linen does.

If this is the case, and please note that I'm not saying it isn't, then
the fabric in flight will be getting it's strength from only the
butyrate until it is stretched enough to engage the fabric. Up until
that point, the fabric is just a filler holding the butyrate together.

It would then follow that the FG/butyrate system would experience more
deflection in light use, even though it has a higher utltimate strength,
because the polyester based systems would engage the stronger fabric
earlier in the defelection. Does this actually occur, and do you have to
account for it by choosing a paint system that will accept the
stretching from the deflection?


--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber