Dear Bret Cahill:
On Saturday, July 14, 2012 11:57:28 AM UTC-7, Bret Cahill wrote:
The heat shield on an exhaust system is metal. It is a conductor, and it also is not a blanket.
Mylar "blankets" provide an intermediate heat transfer surface, one with very low absorptivity (if they have the metal film coating). The also stop forced convection from reaching across the "blanket". The only thing they do not do particularly well is provide a high resistance to conduction.
Two out of three heat transfer methods getting a nod, is pretty good.
David A. Smith
Are we talking about the so-called "Space Blankets"?
They are useful for reflecting heat not because they're made of
mylar. It's the thin film of aluminum that does the heat-reflecting.
Mylar is used because it's very tear-resistant.
Mark L. "sorry if I gave the game away too soon" Fergerson
I noticed the wrong question appeared to be asked.
Certainly not. Mylar's thermal properties are pretty much irrelevant
to how Space Blankets work.
Perhaps it would help if you didn't post the middle of a thread from
another group into sci.physics. I have no idea who you were
questioning, or what went before.
Mark L. Fergerson
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