trailers: fiberglass vs. metal

What is the conventional wisdom on fiberglass top trailers? I've never had
any experience with one. Should I keep it this way and stay away from it by
all means? Or is it OK, really, and not much worse than Al top? How long do
they last and how much maintenance require? What are the pros and cons of
each? I'd think that metal is more durable and virtually maintenance free,
while glass may be a bit lighter. Anything else? Thanks! -- Y

Yuliy Gerchikov wrote:
What is the conventional wisdom on fiberglass top trailers? I've never had
any experience with one. Should I keep it this way and stay away from it by
all means? Or is it OK, really, and not much worse than Al top? How long do
they last and how much maintenance require? What are the pros and cons of
each? I'd think that metal is more durable and virtually maintenance free,
while glass may be a bit lighter. Anything else? Thanks! -- Y

My fiberglass trailer is only 29 years old so I can't comment on
durability. :-) It did get repainted about 5 years ago.
Some claim UV light can penetrate a fiberglass top and that the
accumulated irradiation of the glider will cause damage to the ship. I
used to fly at Boulder, CO where all of the trailers are parked oriented
nearly east-west exposing a long southern face to the Colorado sunshine.
Trailers occupy the same spot for years on end, and, not that I've
taken a poll, but I've never heard of any ships with damage to the top
of one wing and the bottom of the other, or one side of the fuse or fin
due to a fiberglass top.

Shawn

"Shawn" sdotherecurry@bresnannextdotnet wrote:
Some claim UV light can penetrate a fiberglass top and that the
accumulated irradiation of the glider will cause damage to the ship. I
used to fly at Boulder, CO where all of the trailers are parked oriented
nearly east-west exposing a long southern face to the Colorado sunshine.
Trailers occupy the same spot for years on end, and, not that I've taken a
poll, but I've never heard of any ships with damage to the top of one wing
and the bottom of the other, or one side of the fuse or fin due to a
fiberglass top.

Could it be because sun in Colorado in summer shines straight DOWN?
Seriously though, can fiberglass top be painted with aluminum silver (inside
or outside) for added UV protection?

Shawn
--
Y

Yuliy Gerchikov wrote:
"Shawn" wrote:

Some claim UV light can penetrate a fiberglass top and that the
accumulated irradiation of the glider will cause damage to the ship. I
used to fly at Boulder, CO where all of the trailers are parked oriented
nearly east-west exposing a long southern face to the Colorado sunshine.
Trailers occupy the same spot for years on end, and, not that I've taken a
poll, but I've never heard of any ships with damage to the top of one wing
and the bottom of the other, or one side of the fuse or fin due to a
fiberglass top.


Could it be because sun in Colorado in summer shines straight DOWN?

Nah, just feels that way when you haven't used enough sunscreen.
Boulder straddles the 40th parallel, the highest the sun gets at the
summer solstice, is 73.5 deg above the southern horizon, and that's the
cloudy season. All those fair weather cu's :-)

Seriously though, can fiberglass top be painted with aluminum silver (inside
or outside) for added UV protection?

Don't see why not, but what for?

Shawn

Shawn wrote:
Some claim UV light can penetrate a fiberglass top and that the
accumulated irradiation of the glider will cause damage to the ship.

Shawn
Have any of "some" ever done a transmission spectra of the material?
Fat chance. Even window glass cuts of about 400 nm.
...lew...

Lew Hartswick wrote:
Shawn wrote:

Some claim UV light can penetrate a fiberglass top and that the
accumulated irradiation of the glider will cause damage to the ship.
Shawn

Have any of "some" ever done a transmission spectra of the material?
Fat chance. Even window glass cuts of about 400 nm.
...lew...

I suspect some UV gets through fiberglass cloth, it is a woven material,
after all. Not all fiberglass trailer tops are created equally. Some
are a few layers of glass supported by a steel tube frame, some are free
standing glass/foam/glass sandwiches. Some have gelcoat on the outside,
some are painted with polyurethane or acrylic. Some have dark opaque
paint on the inside, some are just left bare.

I had a trailer with a sandwich top, polyurethane on the outside, pretty
grey spackle paint on the inside. I could read a book by the light that
came through the top when I was closed up inside (the glider was also
painted with polyurethane, however, no gelcoat to damage). I had
another trailer with a sandwich top, gelcoat outside, thick dark gray
paint inside, it was totally dark inside. I had yet another trailer
with glass on steel frame, the gelcoat deteriorated, so I had it sanded
and repainted in white automotive acrylic. Within a year or two it was
obvious which parts of the glider were facing upwards in the trailer, as
those parts were distinctly yellower. I've seen a glider which had
badly crazed gelcoat just in those areas that face upward in its
fiberglass top trailer.

An aluminum top protects the glider from UV, even without paint. If I
were to roll the trailer with the glider inside, I'd rather have an
aluminum top. If I lived in a damp warm area, I'd rather have a
fiberglass sandwich top with dark paint on the inside, as there would
likely be a lot less condensation inside the trailer...

Marc

Marc Ramsey wrote:
I had yet another trailer
with glass on steel frame, the gelcoat deteriorated, so I had it sanded
and repainted in white automotive acrylic. Within a year or two it was
obvious which parts of the glider were facing upwards in the trailer, as
those parts were distinctly yellower. I've seen a glider which had
badly crazed gelcoat just in those areas that face upward in its

Now you've done it. Ruined a perfectly good discussion with data. ;-)

Good to know, thanks.

Shawn

Marc Ramsey wrote:

Lew Hartswick wrote:

Shawn wrote:

Some claim UV light can penetrate a fiberglass top and that the
accumulated irradiation of the glider will cause damage to the ship.
Shawn


Have any of "some" ever done a transmission spectra of the material?
Fat chance. Even window glass cuts of about 400 nm.
...lew...


I suspect some UV gets through fiberglass cloth, it is a woven material,
after all. Not all fiberglass trailer tops are created equally. Some
are a few layers of glass supported by a steel tube frame, some are free
standing glass/foam/glass sandwiches. Some have gelcoat on the outside,
some are painted with polyurethane or acrylic. Some have dark opaque
paint on the inside, some are just left bare.

I had a trailer with a sandwich top, polyurethane on the outside, pretty
grey spackle paint on the inside. I could read a book by the light that
came through the top when I was closed up inside (the glider was also
painted with polyurethane, however, no gelcoat to damage).

This is also true of your canopy, but it still stops almost all the UV.
The amount of visible light that penetrates is not a good indication of
the UV shielding. I believe the resins used in composite construction do
a good job of filtering, but I don't have any data for them.

I had
another trailer with a sandwich top, gelcoat outside, thick dark gray
paint inside, it was totally dark inside. I had yet another trailer
with glass on steel frame, the gelcoat deteriorated, so I had it sanded
and repainted in white automotive acrylic. Within a year or two it was
obvious which parts of the glider were facing upwards in the trailer, as
those parts were distinctly yellower. I've seen a glider which had
badly crazed gelcoat just in those areas that face upward in its
fiberglass top trailer.

This discoloration and crazing might also be caused the heat and
dampness in the trailer. The upper foot or so inside a trailer can be
very hot in the summer sun, much hotter than the outside air temperature.

An aluminum top protects the glider from UV, even without paint. If I
were to roll the trailer with the glider inside, I'd rather have an
aluminum top. If I lived in a damp warm area, I'd rather have a
fiberglass sandwich top with dark paint on the inside, as there would
likely be a lot less condensation inside the trailer...

Also my sentiments, though I would also consider an aluminum top that I
insulated.

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

Eric Greenwell
Washington State
USA

Eric Greenwell wrote:
Marc Ramsey wrote:

I had a trailer with a sandwich top, polyurethane on the outside,
pretty grey spackle paint on the inside. I could read a book by the
light that came through the top when I was closed up inside (the
glider was also painted with polyurethane, however, no gelcoat to
damage).

This is also true of your canopy, but it still stops almost all the UV.
The amount of visible light that penetrates is not a good indication of
the UV shielding. I believe the resins used in composite construction do
a good job of filtering, but I don't have any data for them.

True, but it a trailer which admits no visible light is also likely
blocking UV, a trailer that admits visible light may (or may not) be
also passing UV.

I had another trailer with a sandwich top, gelcoat outside, thick
dark gray paint inside, it was totally dark inside. I had yet another
trailer with glass on steel frame, the gelcoat deteriorated, so I had
it sanded and repainted in white automotive acrylic. Within a year or
two it was obvious which parts of the glider were facing upwards in
the trailer, as those parts were distinctly yellower. I've seen a
glider which had badly crazed gelcoat just in those areas that face
upward in its fiberglass top trailer.

This discoloration and crazing might also be caused the heat and
dampness in the trailer. The upper foot or so inside a trailer can be
very hot in the summer sun, much hotter than the outside air temperature.

Except one could also make out the shadows of the wing saddles, etc.,
which is why we concluded it was UV damage.


An aluminum top protects the glider from UV, even without paint. If I
were to roll the trailer with the glider inside, I'd rather have an
aluminum top. If I lived in a damp warm area, I'd rather have a
fiberglass sandwich top with dark paint on the inside, as there would
likely be a lot less condensation inside the trailer...


Also my sentiments, though I would also consider an aluminum top that I
insulated.

I wasn't offered that option with the last trailer I bought, but it
sounds like a good one...

Marc

Lew Hartswick wrote:
Shawn wrote:

Some claim UV light can penetrate a fiberglass top and that the
accumulated irradiation of the glider will cause damage to the ship.
Shawn

Have any of "some" ever done a transmission spectra of the material?
Fat chance. Even window glass cuts of about 400 nm.

Not that I've heard. UV measurement inside trailers has been discussed
here before too.
Why bother if after nearly forty years of glass ships in glass trailers
hasn't shown obvious damage. Lots of crazed finishes in old gliders in
metal trailers too.

Shawn