Time for an old weather guy and pilot to chime in....
Windchill is based on the rate of heat loss from exposed skin caused by wind
and cold. As the wind increases, it draws heat from the body, driving down
skin temperature and eventually the internal body temperature. The only
effect wind chill has on inanimate objects, such as car radiators and water
pipes, is to shorten the amount of time for the object to cool.
The situation is much more complicated with aircraft. Much depends upon
whether or not the aircraft (piston engines) has a temperature and altitude
compensated carburetor or not. If it does not, the carburetor venturi cools
the air by adiabatically expanding the intake air, known as the
Joule-Thomson Effect. If the air temperature drops below the dew point,
moisture in the air condenses into water droplets. Thus, water (and ice
which changes the characteristics of the venturi) can be present in the
carburetor even when flying in clear skies. Ice in the venturi will change
the amount of power the engine develops. Many aircraft beat this problem
either by using a compensated carburetor or by using carburetor "heat" which
keeps the venturi warm stopping ice formation.
Cheers!!
Jim
On Sat, Mar 6, 2010 at 10:18 AM, DAVID GROPPER <kk7ss@verizon.net> wrote:
> I was wrong (again Ed!). I used the wrong word.
>
> I was remembering, from my RAF days --- air that's too cold can be a
> problem.
> I remember piston-engine aircraft at the pole being unable to take off due
> to a lack of power in the polar winter.
> That was the reason for my thinking (I'm gonna have to stop thinking!).
>
> Dave G.
>
>
>
> ----- Original Messages ----
> > From: Bill L <pythias@pacifier.com>
> > Wind chill is an effect on animals.
>
> >From: "WeslakeMonza1330@aol.com" <WeslakeMonza1330@aol.com
>
> > Besides colder air would be better for power.
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--
Cheers!!
Jim
In my many years I have come to a conclusion that one useless man is a
shame, two is a law firm, and three or more is a congress."
John Adams
US diplomat & politician (1735 - 1826)
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