• Altimeter: Hot to cold = look out below?!

    From jonathonlanza@gmail.com@21:1/5 to Mark Kolber on Tue Sep 6 09:57:09 2016
    On Friday, October 29, 1999 at 12:00:00 AM UTC-7, Mark Kolber wrote:
    jcrogin <jcroginNOjcSPAM@yahoo.com.invalid> wrote [snip]:

    I mean, cold air is more dense than hot air. So if
    you fly from hot to cold, why doesn't your altimeter think you're
    flying lower, rather than higher? What am I missing?

    I've gotten this one wrong a million times until I read this
    (highly simplified) explanation in a magazine:

    Imagine your airplane riding on top of a cylinder of air.The cylinder
    sits on the ground and its sides are rigid, but it's capable of
    expanding vertically.

    In general, when air (or any gas) warms, it's volume increases. When
    it cools, its volume decreases. What effect will that have on the
    cylinder your plane is riding on?

    Works the same for low pressure -- generally, low pressure means less
    weight -- more expansion -- more volume.

    ______|______ Mark Kolber
    \(o)/ Denver, Colorado
    o O o www.midlifeflight.com
    replace "spamaway" with "mlf" for email

    Than you for this!!!!!

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