Raimo, thank you for that. I guess the gist of my message that sun derived
heat can be enough to make the structure go soft, even when it is only
second hand heat that has been absorbed by a dark surface. I am certainly
planning to avoid parking on hot tarmac if at all possible. Regards, David
Joyce
----- Original Message -----
From: "Raimo Toivio" <raimo.toivio@rwm.fi>
Sent: Friday, August 03, 2007 1:50 PM
Subject: Re: Europa-List: Europa colours /The facts
MessageAll
who are interested about "colour & temp" topic:
couple of days ago I promised to come back after
finding some real scientific facts instead of "I feel so
knowledge" and here we are:
I have today interviewed two (2) experts, one after one,
just to be sure:
1) Professor Timo Kalema, Energy and Process Technique,
Tampere University of Technology, Tampere Finland
2) Professor Reijo Karvinen, Energy and Process Technique,
Tampere University of Technology, Tampere Finland
http://www.tut.fi/public/
I strictly point both of these gentlemen represents the highest thermal
knowledge:
They BOTH stated as follows:
- direct from the sun the surfaces (Europa upper parts) get SOLAR RADIATION
- the wave lenght is about 1 um
- the colour of the surface is essential because of the thermal absorbtion
- Europas should be painted white or at least light coloured
- that is even more important what nearer equator you are
- from the ground the surfaces (down side parts) get only THERMAL
RADIATION
- the wave lenght is about 10-100 um (depending the ground material)
- the colour of the (plane dn side s) surface is nothing to do w absobtion
of that radiation
- easier observation ratio method:
" go to the shadow and have a white shirt or black shirt on and you still
feel same temperature"
I make the point even clearer: two Europas, one has white coloured down side
wings
and other one has black coloured down side wings. Both has light coloured
upper sides.
Both are standing on the hot black asphalt side by side. If measured the
temperature from
the down side surface, it will be exactly same. That is proved and a fact -
I am sorry !!!
Colour is important only when DIRECT sun solar radiation, and nothing to do
with thermal radiation.
For me personally it is interesting because half of my wings down sides are
light and
half of them are dark. You can be sure I am a happy man today - right
choosing makes
always good for builder - especially aviation safety questions.
Please notice couple of important things:
1) I have dark colour only underside, not sides or upper side (except
letters, thats bad).
2) I do not recommend anybody to paint their Europa uppersides or even sides
anything but white or very light (because of solar radiation). Otherwise be
careful.
3) If you like to paint ONLY underside dark, you can do it where ever you
live and fly,
even in the equator (please do not fly much uppside down!).
4) where ever you live and keep your plane out, be careful when on the
asphalt
because or thermal radiation (nothing to do w planes colour, white or
black). If a hot
day, move it away to the hangar or at least to the grass surface. That is
good
because heat energy makes water in plants to steam and so it is cooler.
5) If you paint it only white, you can forget this topic but please notice
point 4!
Painting only white is easier to paint and maintain and also cheeper to
paint
and maintain but so boring. If its look means nothing, please paint white.
Otherwise you have to think and use your own brains and that is very hard.
Look those Chinese /North Korean girls; all have or used to have
similar green uniform. Sexy?
Karel; this is not only for you but I have done my best to provoke some of
you.
Please do not take personally - your golden strips are extremely beautiful
(those professors told me also some facts about high price heat reflecting
dark metallic colours, I am sure your strips are safe and you can fly peace
in your heart, also in a sunny day).
I hardly can wait comments.
Me personally - will not continue this topic any more. I was right as
usually
and that is enough for me. What is the most important thing - It is not
necessary to repaint my plane. If I would paint it again, I did like to do
same.
Tim: N914XS suffered case 4 - hot asphalt - not a colour relative problem.
Joyce: you wrote "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"
Now you can be sure: your Europas down side colour had nothing to do with
your problems in Morocco. White colour - same situation. The fact is: you
kept
your plane in too hot conditions. Do not fly to hot hell by Europa and if
you do so,
keep it in hangar or in good shadow!
Gentlemen, you can be sure I will take my head of from hot ass now.
And continue to fly my Europa with "dark underside colour"!
This colour topic was a good example of "trust only yourself and your
senses".
And some individuals out there - who have kindly supported me - just thanks.
Raimo
====
Raimo M W Toivio
OH-XRT Europa XS Mono #417, The Experimental of The Year (w DARK UNDERSIDE)
OH-CVK C172 Skyhawk, totally restored 2006-2007
OH-BLL Beechcraft C45, w radial engines (grounded)
37500 Lempaala
Finland
tel + 358 3 3753 777
fax + 358 3 3753 100
gsm + 358 40 590 1450
raimo.toivio@rwm.fi
www.rwm.fi
----- Original Message -----
From: James
To: europa-list@matronics.com
Sent: Tuesday, July 31, 2007 4:45 PM
Subject: RE: Europa-List: Europa colours
Anyone that has a dark color on their plane as a secondary color and not a
stripe, can joke all they want. I saw what went into fixing N914XS and I
can tell you it wasn't funny knowing I had been flying acro in an airplane
that could have at the least had the power plant hanging by half the
firewall halfway thru a loop, or at the worst losing the firewall forward.
You can't reinvent TG. But you CAN reflow epoxy at elevated temps. At
about 200F aeropoxy WILL start to soften. You CAN remove redux with a
hairdryer. And a dark painted composite plane WILL deform sooner or later.
If you think it works on you're aircraft that's fine, but don't go
recommending it to somebody else.
If you cant keep you're hand on it in the sun then it's too hot.
I can't believe so many are willing to kick the devil in the gonads.
Jim T.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Raimo Toivio
Sent: Tuesday, July 31, 2007 6:15 AM
To: europa-list@matronics.com
Subject: Re: Europa-List: Europa colours
Dear Karel,
Yes in Suomi we like to reinvent things and make them better.
Like a phone and the result is history like www.nokia.com
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