canopy tint

Hi all

This has been thrashed out before but a search didnt come up with any difinitive answers, only general observations and personal views.

What opinions have you all on canopy tinting - what color and why?

The tinted canopy looks better from the outside - Yep, I reckon so

The tints seem to lower the temperature inside -really? -HOW? I would have thought the darker color retains more heat than a clear canopy does- am I wrong?
Is there a significant difference in heat reduction from the tint, once the cockpit has cooled after launch?

The lower light within the cockpit makes reading some instruments difficult, especially with age modified eyeballs - I can imagine this to be true, is it a big problem, does it outweigh any benefits?

Does the color chosen improve visibility outside- for seeing haze domes, distanct CU or other aircraft? And therefore, should the color be chosen specifically for where one intends to fly?
For example, the terrain over Australia is generally an entirely different color to that of rural UK or snowy area's in the European Alps or northern US, should the color be matched to these areas?

Aside from reflections being reduced in the darker cockpit, an obvios benefit -especially for DG type canopies, is it mainly a glam thing that only makes the craft look better from outside?

Thanks,

Bagger

bagmaker wrote:

Does the color chosen improve visibility outside- for seeing haze
domes, distanct CU or other aircraft?

With a tinted canopy you are "locked in" to that particular tint. I
prefer to apply my own tint where it counts the most, using sunglasses
(and no tint on the canopy). When flying heat buildup shouldn't be an
issue with proper cockpit venting. On the ground use a canopy cover.

My .02

Regards,

-Doug

On Jul 30, 11:46 pm, bagmaker
wrote:
Hi all



The tints seem to lower the temperature inside -really? -HOW? I would
have thought the darker color retains more heat than a clear canopy
does- am I wrong?
Is there a significant difference in heat reduction from the tint, once
the cockpit has cooled after launch?

The reason canopy tints tend to be blue/green is to reduce IR (not UV)
transmission into the cockpit and it is noticeable when you go from a
tinted canopy to a clear one (as I have done at present) that direct
sun on the face feels hotter. The tint won't significantly reduce
heat buildup from the greenhouse effect from the light wavelengths
that get through.

Does the color chosen improve visibility outside- for seeing haze
domes, distanct CU or other aircraft? And therefore, should the color
be chosen specifically for where one intends to fly?
For example, the terrain over Australia is generally an entirely
different color to that of rural UK or snowy area's in the European
Alps or northern US, should the color be matched to these areas?

The tint colour is not usually amber/yellow (that would be expected to
be better for haze penetration and UV protection) because the
intention is to filter IR rather than blue/UV. UV is already mostly
blocked by a good quality clear canopy. There is a body of opinion
that a blue or green canopy will reduce haze penetration (which it
should do in theory) but a few years ago I reported on RAS trials that
my syndicate partner and I made in a blue tinted canopy Duo comparing
looking through the canopy versus the clear view panel while wearing a
variety of coloured sunglasses. We could find no subjective reduction
in haze penetration.

John Galloway

Thanks,

Bagger

--
bagmaker

Couple of points.

Light scatters more at the higher wavelengths, ie blue. This is why the
orange colored "blue blockers" improve visibility. They block the
scattered light from haze, dust, etc. If you want this effect, you'd
need your canopy tinted the same reddish color of the "blue blocker"
sunglasses.

If the canopy is tinted, the canopy itself should absorb more light.
Because some of the light is blocked and not able to pass through to the
cockpit interior there should be a reduction in temperature in the
cockpit. I suspect that this would not yield a significant difference
in cockpit temperature. One potential downside is that if more light is
absorbed by the canopy, you could potentially experience issues with the
canopy not wanting to close nicely on a hot day due to the additional
thermal expansion.

. *When flying heat buildup shouldn't be an
issue with proper cockpit venting. *On the ground use a canopy cover.

My .02

Regards,

-Doug

Never flown a glider in Arizona, I bet!

Mike

bagmaker wrote:
Hi all
Aside from reflections being reduced in the darker cockpit, an obvio
benefit -especially for DG type canopies, is it mainly a glam thin
that only makes the craft look better from outside?
--
bagmaker

I've flown clear and kinda brown tinted.
It was cooler in the tinted one.
I wear sunglasses so I'm not sure I remember how the tints affected
visibility.

it was just cooler inside

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums...aring/200807/1

There were a few assumptions made in the original post that were
probably wrong and most of them have been corrected in later postings.
I've been involved in lighting and perception for 25 years (see
brianhoodlightingdesign.com for more about that) and can offer some
more opinions.

From the original post:
"I would have thought the darker color retains more heat than a clear
canopy" was responded to with-
'The reason canopy tints tend to be blue/green is to reduce IR (not
UV) transmission into the cockpit and it is noticeable when you go
from a tinted canopy to a clear one (as I have done at present) that
direct sun on the face feels hotter. The tint won't significantly
reduce heat buildup from the greenhouse effect from the light
wavelengths that get through.'

This is mostly correct in my view. First, UV filters made of plastic
tend to be clear while glass UV filters are slightly yellow, but this
has more to do with other factors. UV is by definition not a visible
spectrum so there is no reason for tint to affect UV transmission. On
the other hand, sunlight that is absorbed by a dark canopy (down-
converted to heat in the plastic) would then be cooled by cool air (if
present) passing over the canopy so there could be some benefit there,
plus radiant heat (clear canopy) is much more efficient at heating you
than convective (tinted canopy). In my opinion, tinted is better in
this respect.

From the original post:
"The lower light within the cockpit makes reading some instruments
difficult, especially with age modified eyeballs - I can imagine this
to be true, is it a big problem, does it outweigh any benefits?"

I have to disagree with this. I can't think of any case where the
light levels in the cockpit would fall so low as to prevent easy
viewing of the ASI or altimeter. If you use a PDA it will be much more
visible under a tinted canopy because the contrast ratio (contrast
ratio is a much more important factor than total luminance) is so much
less. The ability of the eye to respond to the very different amounts
of light as it is directed first at a diffuse sky dome and then back
to a dim PDA is the difficult visual task here. In my opinion, tinted
is better in this respect.

Finally,
From the original post:
" no definitive answers, only general observations and personal views"
there will be no definitive answers, because in the end very little is
known about light and how it works on a basic level. That light is
photons that go 186,000mps is a nice theory that is popular but is
contradicted by a lot of other known facts. More to the point, the old
theories of how the eye and brain detect and respond to light via rods
and cones has been quite upset by the research into non-visual
photoreceptors or 'Intrinsically photoreceptive retinal ganglion
cells'. If that is of any interest google 'melanopsin' and go from
there. It's all quite fascinating really, and some of it relates
directly to this question.

Brian





On Jul 30, 3:46 pm, bagmaker
wrote:
Hi all

This has been thrashed out before but a search didnt come up with any
difinitive answers, only general observations and personal views.

What opinions have you all on canopy tinting - what color and why?

The tinted canopy looks better from the outside - Yep, I reckon so

Hi Guys.
I manufacture transparencies

I really believe in changing sunglasses to match conditions.

First, I hate the idea that you can't lighten a canopy on a murky day.

Second, I feel that tinted canopies are a hit and miss quality issue.
Think for a minute about how the canopies are made. A flat piece
of material is stretched either by free blowing or in contact with a tool
surface. This produces areas of flow that make the canopy thinner in
some places than others. The non-uniform thickness means some places are
darker
than others as tint values are depth dependant.

If you are getting roasted in Arizona, stick a piece of dark green cling
film tinting
to the inside of the canopy above your head. You dont spend a lot of time
looking straight up
so the abrupt change from light to dark will not matter, and the temps will
still drop dramatically..

Scott Correa
Spektr Products.

Having flown with a variety of tinted/non-tinted canopies, I would say that
on an average soaring day they seem to make very little difference to
vision and/or heating. In very low light levels (twilight/dark) I'd
prefer to be under a clear lid but practically it wouldn't make a huge
difference.

IMHO you're probably better off with a clear canopy + cover + a decent
pair of sunglasses: at least you can change/remove the sunglasses...

The "Perspex" normally used for glider canopies is transparent from
about 350nm and longer wavelengths, which includes part of the UVA band.
There is enough energy in the photons there to cause skin/tissue damage,
so although you might not visibly "burn" as much as in direct sunlight,
it's not at all good for you. I'm a bit sensitive in this respect so for
me high-factor sunblock is a must in a glider. You can get "UV 400"
Perspex which only lets in visible light but I've never heard of a canopy
being made with it (maybe I should ask!)

On Aug 1, 5:55 am, Ed Downham wrote:
Having flown with a variety of tinted/non-tinted canopies, I would say that
on an average soaring day they seem to make very little difference to
vision and/or heating. In very low light levels (twilight/dark) I'd
prefer to be under a clear lid but practically it wouldn't make a huge
difference.

IMHO you're probably better off with a clear canopy + cover + a decent
pair of sunglasses: at least you can change/remove the sunglasses...

The "Perspex" normally used for glider canopies is transparent from
about 350nm and longer wavelengths, which includes part of the UVA band.
There is enough energy in the photons there to cause skin/tissue damage,
so although you might not visibly "burn" as much as in direct sunlight,
it's not at all good for you. I'm a bit sensitive in this respect so for
me high-factor sunblock is a must in a glider. You can get "UV 400"
Perspex which only lets in visible light but I've never heard of a canopy
being made with it (maybe I should ask!)

Well, you didn't really ask, but here is is anyhow... http://www.thermotecusa.com/
Ray Poquette has been making 98% UV blocker canopies of ALL flavors
for along time. Here is a link to his UV canopy chart:
http://www.thermotecusa.com/ThermoTe...opy%20Info.htm

-Paul