Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Sun, 25 Aug 2002 17:01:51 -0400
Message-ID: <redirect-1711535@logan.com>
From: "Greg Nelson" <gnelson@gt.rr.com>
References: <list-1711319@logan.com>
Subject: Re: [LML] Re: Paint color and skin temp
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The frighteningly-high numbers that are contained in the various
sunlight-v.-color charts should be taken with a grain of salt. What I
remember from my high school physics classes is that light intensity (and
therefore heat) will vary geometrically with the angle that light is being
shined upon a surface, i.e., direct light is more intense than is oblique
light.  Except during high noon during specific times of the year, the sun
never gets a direct hit on most surfaces of your plane,  Further, our planes
are slippery because they have continuously-curved surfaces which slip
directly-shined light just as well as they do air.  Only a few square inches
of surface area of your plane might be in a temperature danger-zone at any
given moment of time.  Further, none of these numbers apply to a plane that
is flying or moving, nor one that is hangared, stored in the shade or where
light-colored wing, canopies and tail covers are used.

My point is that our precision-built planes are not as fragile as we might
first think.  In some ways the occasional intense heat is a net "good" for
the plane as when a heat lamp is used or for hardening paint and body
materials or when an airplane is placed outdoors in the direct sunlight for
several hours to cure body-filling materials in the construction process
Having said this, most heat is not good for your plane and is never good for
electronics, upholstery, plastics, canopies, rubber, etc.  Using dark colors
on the upper-most surfaces of your plane should be avoided as should storing
an airplane in high-heat conditions or unshielded from the elements.   Greg
Nelson