Thread: Things to remember in very hot weather
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Old June 30th 08, 06:26 AM posted to rec.aviation.student,rec.aviation.piloting
Bertie the Bunyip[_25_]
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Default Things to remember in very hot weather
wrote in
:

On Jun 29, 7:23 pm, Steve Hix
wrote:
In article PTV9k.157$K%2.34@trnddc02, "Mike"
wrote:

"Mxsmanic" wrote in message
.. .
Mike writes:

The "real thing" doesn't necessarily require a compressor.

So how does it work?

Some older planes had a non-compressor based system that required
water.
I
assume it was some sort of evaporative cooling setup. I lived in
El Pas
o,
Texas where the temps routinely got above 43° C and I had an
evaporati
ve
cooler in my home that worked just fine.

You can also buy aftermarket systems that use ice.

There are also state-change systems that just need a heat source to
drive them, like Dometic kerosene refrigerators. Not very useful for
aircraft use, granted.

Turbine engined airplanes don't have AC compressors. They bleed
some compressed air from the compressor stage of the engine, run that
through an exchanger to cool it, then drop its pressure, which lowers
its temperature a whole bunch. Mixing this really cold air with hot
bleed air provides whatever temperature the pilot wants.
A piston engine with a larger turbocharger could use some of
the same effect but it would be less effective since the pressures are
lower.


Actually, some turbines do use compressers, like the old RR Dart, for
instance (they call it a spupercharger, it's a rootes type compressor)

The 787 is going back to them in an effort to get away from the problem
of cabin fumes...


Bertie