Sorry Raimo, but this is dangerous thinking for those of us flying in
warmer
climes.
In my previous post I deliberately avoided getting into too much
technical
detail, and I used the word =93reflected=94 where I should have used the
technically correct term =93emitted.=94
First, you seem to misunderstand heat transfer. You are correct that
the
sun=92s energy is not reflected from a black surface. However, a
=93black body=94
is not only a perfect absorber but also a perfect emitter, which is to
say
it may not be reflecting solar heating but it surely emits it. Park on
a
black surface and the solar energy absorbed by that surface will be
re-radiated to the underside of the aircraft, and if that aircraft is
any
color but white it will absorb too much energy. Any material absorbing
energy will increase in temperature. Sure, there will be some
re-radiation
---From the dark aircraft structure but that is irrelevant because the
epoxy-fiberglass will already have softened.
Second, the Lancair aircraft all use a different composite than Europa.
Here=92s how Lancair describes their composites on their web site
http://www.lancair.com/Main/legacy.html ---
=93Like every Lancair, the Legacy=92s major airframe is constructed of
advanced
composite materials. Cured at 270 degrees Fahrenheit under vacuum
pressure,
these NASA tested, epoxy based composites are among the lightest,
strongest,
stiffest materials known.
The high-temperature, pre-impregnated carbon fiber and/or fiberglass
systems
combined with Nomex/honeycomb core materials are considered the supreme
composite airframe materials of choice worldwide.=94
Note that the Lancair=92s composites are cured at a much higher
temperature
than the factory and we cure the Europa structural components. The
=93glass
transition temperature=94 is approximately the cure temperature so
softening
of the composite does not begin until approximately T sub g is reached.
For
a detailed explanation to T sub g see
http://en.wikipedia.org/wiki/Glass_transition_temperature For our
purposes
we can consider the glass transition temperature the softening
temperature,
above which the structure loses a significant portion of its strength.
Anyone contemplating painting a Europa any color other than white
(including
yellow) should review the chart in the Builders Manual, Figure 1,
Colour-Temperature Relationship, on page 36-1 of the Europa XS Tri-Gear
Manual, Issue 1, dated 30 May 1998.
Best regards,
Rob Housman
Irvine, California
Europa XS Tri-Gear
S/N A070
Airframe complete
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Raimo
Toivio
Sent: Friday, July 20, 2007 1:28 AM
Subject: Re: Europa-List: Europa colours
Rob,
I am not going to encourage anybody to paint their
Europa=B4s undersides any colour but white. I still well
remember Manual=B4s words: all the Europas must be white.
I still have to point out the energy of the sun is NOT
reflecting out of the black asphalt IMHO. That is why
it is hot when a sunny day. It absorbs allmost all the heat
energy and nothing is reflecting out. White surfaces are
cool because they are reflecting out much more.
So it could be more dangerous to keep it on the snow covered
surface while a sunny day (or on white sand or water w Europa floats!).
In Sweden there has been 10 years a wonderful full colour mid red
Lancair
320
and no composite problems at all. Register # is SE-XOP (!). And like
we all know in South America (Columbia?) there is flying a total deep
yellow
Europa.
I think - with other colour as white - it is better to be even more
careful.
Beauty is a good reason for some extra work and some sacrifice.
That is the fact all the women know. That is all.
"Keep your full matt black Europa in the hangar and fly only night time
if
you wanna be absolutely sure"
Raimo
----- Original Message -----
From: Rob Housman <mailto:robh@hyperion-ef.com>
Sent: Friday, July 20, 2007 2:32 AM
Subject: RE: Europa-List: Europa rules
Mike '
In re: dark paint
Don=92t even think about it. Where we live and fly, on warm days the
heat
reflected off the ramp will be sufficient to soften the epoxy-fiberglass
enough to reduce the strength of the structure. Sure it will be OK at
altitude but you still have to climb away from the surface. Folks
flying
closer to the Arctic Circle don=92t have to worry about getting the
airframe
too hot.
Best regards,
Rob Housman
Irvine, California
Europa XS Tri-Gear
S/N A070
Airframe complete
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of
DuaneFamly@aol.com
Sent: Thursday, July 19, 2007 3:23 PM
Subject: Re: Europa-List: Europa rules
Raimo,
Congratulations to you and your aircraft. I think we can all stand a
little
taller and more proud when one of "our" planes tops the list of all in
an
entire country.
Do you have any pix of you panel? Is the underside of your aircraft
really
painted dark? Black, blue, brown? Any reasoning for this?
Mike Duane A207A
Redding, California
XS Conventional Gear
Jabiru 3300
Sensenich R64Z N
Ground Adjustable Prop
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