Desert Sailplane storage

[Charles McLaurin]

I just moved from Virginia where my glider was stored
inside a hangar to El Paso, Texas. For the time being,
I will have to store it in my enclosed trailer outside.
I own a fiberglass Concept70 with metal flaps. Any
of you desert flyers have any tips, warnings, suggestions
about storage.
Charlie mcLaurin

[[email protected]]

Charles McLaurin wrote:
> I just moved from Virginia where my glider was stored
> inside a hangar to El Paso, Texas. For the time being,
> I will have to store it in my enclosed trailer outside.
> I own a fiberglass Concept70 with metal flaps. Any
> of you desert flyers have any tips, warnings, suggestions
> about storage.
> Charlie mcLaurin
I know that the material used in most canopies is hygroscopic which is
one reason they tend to warp when a glider is moved from a dryer
climate to a more humid one. In fact, when I purchased a Ventus which
had spent most of its time in a dry climate and moved it to southern
Florida, it was not long (a few weeks) before I had to have assistance
closing the canopy before each flight. In addition, I have heard that
gelcoat is also hygroscopic and tends to absorb moisture which is one
reason gliders get heavier over time in humid climates.
I'm curious if anyone has advice on moving from a humid climate to a
dry one on the impact, if any, to a glider. I myself will be moving
next year to a dryer climate and I will be bringing my glider with me.
As to the post above, the one piece of advice I have consistently heard
is that fiberglass trailers do not block all the UV, therefore it is
prudent to coat the inside of the trailer with a UV blocking paint. Or
keep the glider in a hangar. A good solar vent is also cheap insurance
if you can reduce any potential condensation inside the trailer by
keeping the air moving.
Respectfully,

[Eric Greenwell]

wrote:

> As to the post above, the one piece of advice I have consistently heard
> is that fiberglass trailers do not block all the UV, therefore it is
> prudent to coat the inside of the trailer with a UV blocking paint. Or
> keep the glider in a hangar.

I've heard this, too. Has anyone measured the UV transmission of a
glider trailer top? Since most plastic absorbs UV well, it's hard to
imagine much of the UV gets through the resin (and the paint, if that's
used). Glass also absorbs UV, so I'd expect the fiberglass to also
reduce the UV.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[Robertmudd1u]

> Has anyone measured the UV transmission of a
>glider trailer top? Since most plastic absorbs UV well, it's hard to
>imagine much of the UV gets through the resin (and the paint, if that's
>used).

All new Cobra trailers are painted black inside and have been for some time for
just this reason. My 1999 one is black inside.


Robert Mudd

[GM]

Robertmudd1u wrote:
> snip>
> All new Cobra trailers are painted black inside and have been for
some time for
> just this reason. My 1999 one is black inside.
>
>
> Robert Mudd

One could also epoxy a layer of heavy duty houshold aluminum foil to
the inside of a fiber-glass shell trailer. If any UV radiation gets
through that, we have a much bigger problem on our hands. ;-)
Uli Neumann

[Shawn]

GM wrote:
> Robertmudd1u wrote:
>
>>snip>
>>All new Cobra trailers are painted black inside and have been for
>
> some time for
>
>>just this reason. My 1999 one is black inside.
>>
>>
>>Robert Mudd
>
>
> One could also epoxy a layer of heavy duty houshold aluminum foil to
> the inside of a fiber-glass shell trailer. If any UV radiation gets
> through that, we have a much bigger problem on our hands. ;-)
> Uli Neumann
>
I was thinking of using 3M adhesive spray for this. Then again, my ship
is 27 yo and has lived most of its life in a fiberglass trailer in
Colorado (5500-7500 ft msl), so what really is the point?

Shawn

[Jim Vincent]

I think the key question is, Has anyone done any studies to see how much UV
really penetrates through the trailer? Solutions are great, but I really
question whether any UV really does penetrate through the paint and fiberglass
shell.


Jim Vincent
N483SZ

[GM]

Jim Vincent wrote:
> I think the key question is, Has anyone done any studies to see how
much UV
> really penetrates through the trailer? Solutions are great, but I
really
> question whether any UV really does penetrate through the paint and
fiberglass
> shell.
>
>
> Jim Vincent
> N483SZ
>

Jim,

I raised that question with the 'Experts' of Edmund Optical. They were
clueless as far as detecting and/or measuring UV light. Does anybody
have a practical idea? Are there UV-meters?

Uli Neumann

[Jim Vincent]

>I raised that question with the 'Experts' of Edmund Optical. They were
>clueless as far as detecting and/or measuring UV light. Does anybody
>have a practical idea? Are there UV-meters?
>

I googled around and found a company called solar.com that happens to be in my
area. I'll call them on Tuesday and see if they might be willing to loan me an
instrument for 20 minutes. I'm willing to drive my trailer down to their
office to see what the results are. I'll post any results here.

Jim Vincent
N483SZ

[Kilo Charlie]

A somewhat easier solution is to get a "black light" out of your attic from
when you had all of those black light posters in high school...they transmit
mostly UV-A. Have someone stand on the outside of your trailer at night and
crawl inside to see what light is transmitted. Little if any gets through
but you would do best to prove it to yourself.

Besides it may even inspire you to take a trip down to the local "head shop"
and buy a few more posters of Jimi Hendrix. ;-)

Casey Lenox
KC
Phoenix

[Jim Vincent]

>
>A somewhat easier solution is to get a "black light" out of your attic from
>when you had all of those black light posters in high school..

Can't do that...I still use mine! Hendrix rules, dude!

Jim Vincent
N483SZ

[Marian Aldenhövel]

Hi,

> Are there UV-meters?

There is a very crude method using test-strips that are sometimes
distributed in pharmacies here in germany, especially in the summer
holiday season. These strips are meant to help people avoid sunburn
by indicating a safe time to spend in the sun.

They are made of cardboard and some UV-sensitive paint covered in
some kind of goo. You are supposed to rub off the goo when you go
out. Put the strip next to you on the beach and when it has
changed color according to a scale and instructions printed next
to it you better get out of the sun.

One could use two of these: Put one on the outside of the trailer
and one inside. Time how long it takes the one on the outside to
discolor to a certain degree. Wait until the one on the inside has
taken the same amount of UV. Divide the times and you should arrive
at a rough estimate of how much UV gets through the trailer.

I do not know of anyone who has made such an experiment on a glider
trailer. I did it for car windows a few years ago.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de
"Flying an An-2 is like making love to a fat lady who's had too much to drink:
there's a lot to work with, it's unresponsive, you're never quite sure when
you're there, and it's big-time ugly."

[Jim Vincent]

> somewhat easier solution is to get a "black light" out of your attic from
>when you had all of those black light posters in high school...they transmit

I don't think that would work. A black light transmits both in the visible
light and UV frequency spectrums. Each frequency is attenuated, reflected, or
absorbed differently by a material.

If you see light coming through the trailer when shining the black light, all
you can deduce is that the visible light transmitted through the trailer,
nothing about whether the UV.

Jim Vincent
N483SZ

[Shawn]

Jim Vincent wrote:
>>somewhat easier solution is to get a "black light" out of your attic from
>>when you had all of those black light posters in high school...they transmit
>
>
> I don't think that would work. A black light transmits both in the visible
> light and UV frequency spectrums. Each frequency is attenuated, reflected, or
> absorbed differently by a material.
>
> If you see light coming through the trailer when shining the black light, all
> you can deduce is that the visible light transmitted through the trailer,
> nothing about whether the UV.

You have to bring your Metallica black light poster with you and see if
it glows.

Shawn

[Jim Vincent]

I called around to some testing labs. I spoke first to a local company in the
Philly area, but the guy was not willing to do a freebie...Philly Attitude.

I then spoke with a company in Plainfield, IL that is willing to spend a few
minutes on the project!

If there is someone on this group that lives near Plainfield, IL (north of
Juliett) and is willing to drive their trailer for some testing, please
contact me directly for the company contact.

Or maybe someone out west could pursue this with a local company there.

With a little planning, we could test a few different materials. Go out on a
sunny day, get a reference reading, then test in the trailer. Perhaps also
make a small box on which we can put different covers such as tin foil, paint,
wood, etc and measure the UV ingress.

Let me know!

Jim Vincent
N483SZ

[John Galloway]

What about a Cobra owner contacting Herr Spindelberger
to ask what information he has on the subject?

John Galloway


At 16:30 28 December 2004, Jim Vincent wrote:
>I called around to some testing labs. I spoke first
>to a local company in the
>Philly area, but the guy was not willing to do a freebie...Philly
>>Attitude.
>
>I then spoke with a company in Plainfield, IL that
>is willing to spend a few
>minutes on the project!
>
>If there is someone on this group that lives near Plainfield,
>IL (north of
>Juliett) and is willing to drive their trailer for
>some testing, please
>contact me directly for the company contact.
>
>Or maybe someone out west could pursue this with a
>local company there.
>
>With a little planning, we could test a few different
>materials. Go out on a
>sunny day, get a reference reading, then test in the
>trailer. Perhaps also
>make a small box on which we can put different covers
>such as tin foil, paint,
>wood, etc and measure the UV ingress.
>
>Let me know!
>
>Jim Vincent
>N483SZ

>

[Kilo Charlie]

UV-A and UV-B light penetrates poorly through anything that is tinted. Also
tightly woven materials do not allow penetration. Most of us have had "tan
lines" at some point with your skin being pasty white under your bathing
suit or shirt while the exposed areas are tan or burned.

With a reflective white coating on the outside and the opaque nature of
fiberglass it is highly unlikely that any substantial amount of UV light
gets to the inside of anyones trailer. If anyones wishes to have references
for the science of it all just let me know.

Casey Lenox
KC
Phoenix

[Jim Vincent]

>If anyones wishes to have references
>for the science of it all just let me know.

Casey,

I for one would much appreciate a link to a site listing the transmissivity of
frp. I agree with you that UV transmits minimally if at all through a trailer,
but would love some emperical numbers.

Jim Vincent
N483SZ

[Kilo Charlie]

Hi Jim-

Try this one for starters:

This page discusses the penetration of UV light in plastics:
http://www.newton.dep.anl.gov/askasci/eng99/eng99272.htm

Also for those of you who seriously wish to do your own experiment re UV
penetration into your trailer (or whatever else you can think of) here is a
site that sells UV sensitive beads for cheap...$7 (US). The cheapest UV
meters are around $150 (US).
http://www.stevespanglerscience.com/product/1350

I have no financial interest in any of this BTW. I am thinking that I just
might put up a few posters again...chalk it up to midlife crisis. Not so
sure that the wife will tolerate it though.

Casey

[B Lacovara]

We have a fair amount of research available on the effects of UV on gel coat,
including some just completed work that will be presented at the SSA
convention. Here are some of the pertinent facts:

Light energy (radiation) varies throughout the spectral band, from ultraviolet,
to visible, to infrared. The most energetic region of the spectrum is the UV
range (<400 nm)) - potentially the most damaging to polymer surfaces… not to
mention one's skin. For study proposes the UV range of the spectrum is divided
into three categories - UV-A, UV-B, and UV-C.

The UV-A region (wavelengths 400-315 nm) has an affect on polymers. These
wavelengths will transmit through window glass (used as a benchmark). UV-B
(315-280 nm) is highly energetic and will result in degradation of polymers.
UV-B is the shortest wavelength to reach the earth's surface, however it is
effectively filtered out by window glass. UV-C (<280 nm) is the most energetic
UV band, however it is filtered out by the atmosphere and is only found in
space.

So, UV-C is a non-issue. UV-B is potentially harmful but is easily absorbed by
window glass and to a much higher degree by gel coat. The titanium dioxide
(TiO2) pigment in white gel coat is particularly good at mitigating UV-B
penetration. UV-A is the least energetic within that portion of the spectrum.
While it will transmit through window glass, again the TiO2 pigment in white
gel coat is particularly effective at absorbing and limiting the transmission
of this wavelength.

While UV exposure impacts the photo-aging of the gel coat surface, UV
penetration through the gel coat and into the laminate substrate is not an
issue. The end result is that UV damage to the underlying laminate does not
occur. Taking this a step further there is little cause for concern with UV
penetrating a trailer - the wavelengths are simply too short to make it through
a gel coated laminate. The idea of painting the inside of a trailer reduces
the penetration of longer wavelengths that are not harmful to polymers, but
rather contribute to solar heating inside the trailer.

Bob Lacovara
American Composites
Manufacturers Association

[Kilo Charlie]

Great discussion Bob....thanks! Any chance that your convention talk will
be published somewhere?

Casey Lenox
KC
Phoenix

[Jim Vincent]

Bob, Thanks for your detailed insights. What are your thoughts on the affects
of a fiberglass trailer painted with regular ol' paint instead of gel coat.
Does any UV make it through the trailer to affect the glider within? TIA.

Jim Vincent
N483SZ

[Stefan]

Jim Vincent wrote:

> Bob, Thanks for your detailed insights. What are your thoughts on the affects
> of a fiberglass trailer painted with regular ol' paint instead of gel coat.
> Does any UV make it through the trailer to affect the glider within? TIA.

I don't know whether the UV will make it into the trailer. However, I do
know that the UV will destroy the "regular old paint" rather quickly. In
another life, I owned a wooden boat which was on the water the whole
year without a cover. The UV literally burnt the whole paint away within
two years. And this wasn't "regular old paint", but specialized UV
resistant boat varnish.

Stefan

[B Lacovara]

<<Great discussion Bob....thanks! Any chance that your convention talk will
be published somewhere?
>>

The technical paper is scheduled to be published at an industry conference next
October. However, I'll be happy to make the SSA presentation available when
it's complete.

Bob

[B Lacovara]

<<Great discussion Bob....thanks! Any chance that your convention talk will
be published somewhere?
>>

Will be happy to share convention presentation when finished. The formal
technical paper will be presented at a technical conference on October.

<<Bob, Thanks for your detailed insights. What are your thoughts on the
affects of a fiberglass trailer painted with regular ol' paint instead of gel
coat.
Does any UV make it through the trailer to affect the glider within? TIA.>>

If the regular ol' paint happens to be urethane it is not much different from
gel coat - almost all white coatings use TiO2 pigment, so the inherent UV
penetration is not an issue. Of course there is a wide range of photo-aging
performance with various types of paints.

One difference between gel coat and paint is the thickness. Because a paint
film is typically thinner than gel coat it will allow more long-wave
penetration (not harmful to polymer surfaces), but may allow more solar heating
inside a trailer. I've never seen any actual data describing the difference, so
don't know how significant the delta might be.

Bob