In this respect it may interest owners to know that my Europa came back from
our trip to Morocco last year with ripples/dimples in the skin corresponding
to where the heels of pilot and passenger go in normal flying position. My
guess is that we parked the plane on some particularly hot black tarmac, in
front of a closed aluminium hangar door that was reflecting extra sunlight
onto that tarmac. The heat radiating from the ground to the underside of the
plane was enough to soften it, so that heel pressure when we got back in
distorted the skins!
It is worth taking the skin colour and heating possibilities
seriously! Regards, David Joyce G-XSDJ
----- Original Message -----
From: "Rob Housman" <robh@hyperion-ef.com>
Sent: Friday, July 20, 2007 4:02 PM
Subject: RE: Europa-List: Europa colours
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 "reflected" where I should have used the
technically correct term "emitted."
First, you seem to misunderstand heat transfer. You are correct that the
sun's energy is not reflected from a black surface. However, a "black body"
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's how Lancair describes their composites on their web site
http://www.lancair.com/Main/legacy.html ---
"Like every Lancair, the Legacy's 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."
Note that the Lancair's composites are cured at a much higher temperature
than the factory and we cure the Europa structural components. The "glass
transition temperature" 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
Europas undersides any colour but white. I still well
remember Manuals 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't 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't 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
_____
<http://discover.aol.com/memed/aolcom30tour/?ncid=AOLAOF00020000000982> .
http://www.matronics.com/Navigator?Europa-List
http://forums.matronics.com
href="http://www.matronics.com/Navigator?Europa-List";>http://www.matronhref
"http://forums.matronics.com";>http://forums.matronics.com
|