Re: What colour?

[clare @ snyder.on .ca]

On Sun, 03 Aug 2003 01:45:03 GMT, "John Nicholson"
> wrote:

>What are the factors that go into deciding what colour to paint your
>aircraft?
>
>I like some of the sexy reds (they go faster) and other colours but the fact
>that most aircraft are painted white leads me to conclude that there is
>something else to all this.
>
>In my case, the aircraft will not (unfortunately) be hangared.
>
>John
>
Metal, fabric, or compost?
As compost airplanes can go soft in the heat, like a giant cheese,
most are painted white to reduce heat absorption while sitting in the
sun.

[John Nicholson]

The aircraft is a composite Lancair 360.

<clare @ snyder.on .ca> wrote in message
...
> On Sun, 03 Aug 2003 01:45:03 GMT, "John Nicholson"
> > wrote:
>
> >What are the factors that go into deciding what colour to paint your
> >aircraft?
> >
> >I like some of the sexy reds (they go faster) and other colours but the
fact
> >that most aircraft are painted white leads me to conclude that there is
> >something else to all this.
> >
> >In my case, the aircraft will not (unfortunately) be hangared.
> >
> >John
> >
> Metal, fabric, or compost?
> As compost airplanes can go soft in the heat, like a giant cheese,
> most are painted white to reduce heat absorption while sitting in the
> sun.

[BD5ER]

>The aircraft is a composite Lancair 360.

Looks like you should stick to the light colors, white, yellow, silver etc, and
keep the dark trim colors to a minimum.

I once took one of those infrared heat guns with me to the auto auction (1000+
vehicles) on a wind free day. While there can be some error with the IR units
I did come up with some real surprises - like silvers that get WAY hotter than
you would expect and some rather dark colors that weren't that bad. I suspect
there is more to how hot the paint gets than just the color, like the kind of
flake, pearl, or even the clear coat.

White is boreing, but it's the only fool-proof color I know to paint a
composite plane.

[B2431]

>I once took one of those infrared heat guns with me to the auto auction

IR radiometer ?

Dan, U. S. Air Force, retired

[spektr]

"BD5ER" > wrote in message
...
> White is boreing, but it's the only fool-proof color I know to paint a
> composite plane.

Well alrighty then....

The Germans have been building glass ships longer than anyone.
They are all delivered white with small patches of trim color,
usually high vis red/orange on the nose, wingtips and tail.
The anti-collision markings are JAR22 mandated, but the
white finishes arent. They probably know something we don't.

Scott

[Stealth Pilot]

On 03 Aug 2003 05:18:46 GMT, (BD5ER) wrote:

>>The aircraft is a composite Lancair 360.
>
>Looks like you should stick to the light colors, white, yellow, silver etc, and
>keep the dark trim colors to a minimum.
>
>I once took one of those infrared heat guns with me to the auto auction (1000+
>vehicles) on a wind free day. While there can be some error with the IR units
>I did come up with some real surprises - like silvers that get WAY hotter than
>you would expect and some rather dark colors that weren't that bad. I suspect
>there is more to how hot the paint gets than just the color, like the kind of
>flake, pearl, or even the clear coat.
>
>White is boreing, but it's the only fool-proof color I know to paint a
>composite plane.

I saw some figures once from the world of architecture. it showed that
the infra red transmissibility performance of paints was considerably
different from the apparent colour.
since the thermal end of the spectrum is IR it would pay to do some
objective testing of the paints in that spectrum area before settling
on the favourite colour.
sorry but this was 20 years ago and I dont have access to the
publication. I can verify the veracity of your comments though.
Stealth Pilot
Australia

[B2431]

>
>>>I once took one of those infrared heat guns with me to the auto auction
>>
>>IR radiometer ?
>
>"Heat guns" was a POOR choice of words. The only gun I pack as a Glock. <G>
>
>Raytek non-contact IR pyrometer - would have been more accurate.
>
I used to be a gunsmith, you can keep your Glockâ„¢. I carry what goes with
what I am wearing. My 45 won't conceal very well with shorts.

Back in 1973 I used to work for a company that made IR radiometers. I guess the
difference between pyrometers and radiometers is in the eye of the beholder.

As for the emissivity of paints perhaps a single layer sheet of the composite
you intend to build your flying machine with can be used for tests. Paint small
spots with the actual paint you's like to use. Place the sheet out in the sun
and measure the temperature from the reverse side at each spot using your
radiometer. Do this as soon as you place the sheet in the sun. Then again at
each half hour interval there after including cool down times as the sun sets.
This will allow you to plot a rough curve for each colour.


Dan, U. S. Air Force, retired

[BD5ER]

>As for the emissivity of paints perhaps a single layer sheet of the composite
>you intend to build your flying machine with can be used for tests. Paint
>small
>spots with the actual paint you's like to use. Place the sheet out in the sun
>and measure the temperature from the reverse side at each spot using your
>radiometer. Do this as soon as you place the sheet in the sun.

Sounds like a reasonable test. If I only had the time. Mine will probably be
white.

>I used to be a gunsmith, you can keep your Glockâ„¢

I intend to. 8 years, about 11 cases of ammo, 2 misfires from bad factory
ammo, and one from the gun due to stupid owner. It hits what it is pointed at,
now if I could just point it better...........Other than that I'm happy with
it.

[Corrie]

Ran across a site of a fellow building a Falco. Naturally, he wanted
it red. Had the rudder painted, while the rest was still
primer-white. Measured the temp out in the sun one day and the red
rudder was waaay hotter than the white fin. He decided that a white
Falco was still fast and sexy.

[Jay]

The reason your silver aircraft may have showed up so hot is because
your "heat gun" was actually peering at the image of the sun reflected
off the glossy surface. But its is true, the apparent color seems to
have little correlation to its IR characteristics. The guy that
suggeted using the back surface of a test panel and measuring the
temperature directly (thermocouple into to DMM or non contact
thermometer) was right on. Also, you could always go two tone on your
airplane with the top surfaces being IR reflective (and preferably
visible light absorbative on the cowl) and the other surfaces any
color you want.

(BD5ER) wrote in message >...
> >The aircraft is a composite Lancair 360.
>
> Looks like you should stick to the light colors, white, yellow, silver etc, and
> keep the dark trim colors to a minimum.
>
> I once took one of those infrared heat guns with me to the auto auction (1000+
> vehicles) on a wind free day. While there can be some error with the IR units
> I did come up with some real surprises - like silvers that get WAY hotter than
> you would expect and some rather dark colors that weren't that bad. I suspect
> there is more to how hot the paint gets than just the color, like the kind of
> flake, pearl, or even the clear coat.
>
> White is boreing, but it's the only fool-proof color I know to paint a
> composite plane.

[[email protected]]

On 03 Aug 2003 19:38:24 GMT, (BD5ER) wrote:

:>As for the emissivity of paints perhaps a single layer sheet of the composite
:>you intend to build your flying machine with can be used for tests. Paint
:>small
:>spots with the actual paint you's like to use. Place the sheet out in the sun
:>and measure the temperature from the reverse side at each spot using your
:>radiometer. Do this as soon as you place the sheet in the sun.
:
:Sounds like a reasonable test. If I only had the time. Mine will probably be
:white.
:
:>I used to be a gunsmith, you can keep your Glock™
:
:I intend to. 8 years, about 11 cases of ammo, 2 misfires from bad factory
:ammo, and one from the gun due to stupid owner. It hits what it is pointed at,
:now if I could just point it better...........Other than that I'm happy with
:it.

What cal? I'm shooting .357 in mine, but thinking about going back to
..40.

[Ernest Christley]

Roger Halstead wrote:

> It's been my experience which is admittedly limited, that metallic
> colors/pigments tend to get hotter than the same colors with out the
> metallic pigment. (hope I phrased that correctly)
>
> Roger Halstead (K8RI EN73 & ARRL Life Member)
> www.rogerhalstead.com
> N833R World's oldest Debonair? (S# CD-2)
>
>

Would that be because the non-metallic paints have a much lower
coefficient of heat transfer? That is, the very outer layer heats up,
but then acts as insulation and doesn't transfer the heat energy any
deeper. The higher metal content would work as a heat wick.

Just guessing.

--
----Because I can----
http://www.ernest.isa-geek.org/
------------------------

[Jay]

Roger Halstead > wrote in message >...
> On 4 Aug 2003 12:37:54 -0700, (Jay) wrote:
>
> >The reason your silver aircraft may have showed up so hot is because
> >your "heat gun" was actually peering at the image of the sun reflected
> >off the glossy surface. But its is true, the apparent color seems to
>
> Shiny Aluminum gets really hot in direct sunlight.
> At work we had a 1 inch thick 4' X 8' Aluminum plate laying on blocks
> out in the sun. It was in a protected area where it had little
> cooling. It actually got hot enough to burn a person trying to move
> it. The temperature was only slightly below the boiling point for
> water...bout 200 F.
>
> I always figured shiny Aluminum wouldn't get all that hot until I saw
> that.

Your perception of it being hot was based on the material conducting
heat into your fingers when you touched it. Plain aluminum is an
exceptionally good conductor of heat as opposed to a layer of paint
over the same material. Example: This guy I worked with told me that
growing up in Minnesota, they put a layer of styrofoam on the seat of
the outhouse so in the freezing winter they wouldn't get stuck. The
styrofoam was certainly below freezing when they sat down, but because
its ability to conduct heat was so small, it didn't freeze their
empennage off.

So a painted airplane could have a higher actual temperature but less
ability to make your finger feel hot when you touch it.

[BD5ER]

>Your perception of it being hot was based on the material conducting
>heat into your fingers when you touched it.

This is why I just always assumed that the wrenches I left out in the sun
"felt" so hot, but the other day I happened to leave some tools on the outside
window sill of my shop. When I went to retrieve them they were almost too hot
to hold. The strange thing is that the one black impact extension was far
cooler to the touch than the chrome ones.

I think there is a lot more to heat gain than just color and surface finish
than those of us unschooled in the ways of IR understand.

[Richard Lamb]

The .22 is quieter...

wrote:
>
> On 03 Aug 2003 19:38:24 GMT, (BD5ER) wrote:
>
> :>As for the emissivity of paints perhaps a single layer sheet of the composite
> :>you intend to build your flying machine with can be used for tests. Paint
> :>small
> :>spots with the actual paint you's like to use. Place the sheet out in the sun
> :>and measure the temperature from the reverse side at each spot using your
> :>radiometer. Do this as soon as you place the sheet in the sun.
> :
> :Sounds like a reasonable test. If I only had the time. Mine will probably be
> :white.
> :
> :>I used to be a gunsmith, you can keep your Glock™
> :
> :I intend to. 8 years, about 11 cases of ammo, 2 misfires from bad factory
> :ammo, and one from the gun due to stupid owner. It hits what it is pointed at,
> :now if I could just point it better...........Other than that I'm happy with
> :it.
>
> What cal? I'm shooting .357 in mine, but thinking about going back to
> .40.

[Larry Smith]

"Dan Thomas" > wrote in message
om...
> Colour selection should be based on more than its emissivity. You want
> something that will stand out if the Search and Rescue boys have to go
> start looking for you. ELTs are fine, but they often don't work
> properly

At 57A yesterday they had 50-some airplanes to search for a screaming ELT.
Whup-whup-whup-whup-wooop-wooop-wooooop-woooop-woooop.

They came by the hangar and harassed a few of us then went on, after I tore
into the rear sling to see if mine was on. They finally found it in an
airplane that had just landed, apparently about 10 feet above the asphalt.

[Fastglasair]

>I've seen large areas covered with bright orange trees in the fall. Never
>seen any blue trees though.

What about "Blue" Spruce?

[Dan Thomas]

(Fastglasair) wrote in message >...
> >I've seen large areas covered with bright orange trees in the fall. Never
> >seen any blue trees though.
>
> What about "Blue" Spruce?



Blue Spruce ain't very blue. A bright blue, like an intense sky-blue,
is an eye-catcher.
My favorite is a yellow with a hint of green (my Jodel proves it)
and I'll be locatable unless I go down in a canola field in June.
Notice that fire engines are using such colors these days. I
believe it was a result of research to find the most arresting shades.

Dan

[clare @ snyder.on .ca]

On 9 Aug 2003 09:21:47 -0700, (Dan Thomas)
wrote:

(Fastglasair) wrote in message >...
>> >I've seen large areas covered with bright orange trees in the fall. Never
>> >seen any blue trees though.
>>
>> What about "Blue" Spruce?
>
>
>
> Blue Spruce ain't very blue. A bright blue, like an intense sky-blue,
>is an eye-catcher.
> My favorite is a yellow with a hint of green (my Jodel proves it)
>and I'll be locatable unless I go down in a canola field in June.
> Notice that fire engines are using such colors these days. I
>believe it was a result of research to find the most arresting shades.
>
> Dan
Cromium Yellow is used for fire trucks because it shows up best
through smoke, fog, and snow. Red dissapears in those conditions (goes
black)
Our plane will likely be "cub yellow" with blue or green highlights.