"George Patterson" wrote in message
...


"Steve.T" wrote:

The composite materials are used as insulation in certain cases. Think
of fiberglass.

Fiberglass, in and of itself, is not a particularly good insulator. When
it's
spun into a sort of glass wool and traps a lot of small air bubbles, that
changes. The air *is* a good insulator.

Depends on how you look at it. In the long-wavelength infrared
spectra the atmosphere is virtually transparent. In that regard, air is an
excellent conductor since it poses no resistance to thermal radiation. And
it is the radiation that accounts for the type of heat loss involved in
these discussions, not conduction. So it is the thermal emissivity of the
wing surface that really matters -- not the molecular conductivity.