[aprssig] Balloon warmth
noskosteve at yahoo.com
Wed Mar 24 10:02:04 CDT 2010
The sealed plastic pouch versions don't use air. It is a reversible exothermic chemical reaction. This is the ones with the metal popple disk.
I think they have a super saturated solution of an acetate salt, perhaps sodium acetate. There's several YouTube videos showing the process - ad nausium...
at fractions of an inch of mercury the Iron compound versions will die.
-- 73, Steve, K9DCI
--- On Wed, 3/24/10, Scott Miller <scott at opentrac.org> wrote:
> About a dozen people have suggested
> this, but I'm not convinced the oxygen level is
> sufficient. I do happen to have a vacuum chamber in
> the shop, so once I get a functioning payload again I'll
> have to throw a few of those in there and compare the heat
> generated to a control at 1 atmosphere.
> AD4BL wrote:
> > An alternative to keeping equipment warm on a balloon
> flight is to use the hand warmers. They
> last about
> > 8 hours and provide enough heat to keep equipment
> operating in a cold environment.
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