Both are important, and both are long term, not short term problems.
What's significant is that the same thing you do to achieve protection of
one element (heat or UV) also, by happenstance, helps to protect from the
other element.
I have to say; if any composite resin gets "soft" when heated in direct
sun (no matter what color it's painted), I'd say that's a good reason to
never fly that aircraft again. A resin that gets soft in daytime sun is a
resin that was not properly cured (mixed wrong?) and is not airworthy in any
way and never will be. Makes me glad I'm building an RV :-)

MJC

wrote in message
...
On Wed, 13 Jul 2005 08:25:00 -0500, "MJC" wrote:

Any really light, bright color should be fine, but white is definitely
the
best for UV protection. Another question to ask yourself is if you'll be
keeping it in an enclosed hangar most of the time. If so, then it's
almost a
non-issue.


From what I've gathered, it's not the UV protection, it is heat
absorption. Fiberglass composite gets "soft" when overheated, and
white and several other colours do not heat up as much as black, red,
and several other colours.

MJC