Re: B747 technical questions

Date:         28 Jul 97 01:13:28 
From:         "Gary Welch" <garywelch@flex.net>
Organization: Compaq
References:   1 2 3 4
Followups:    1 2 3
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Merlin Dorfman <dorfman@netcom.com> wrote in article
<airliners.1997.1484@ohare.Chicago.COM>...
> Jay Biederman (jbb@seanet.com) wrote:
> : Actually the tires are inflated with nitrogen gas. This is because the
> : tire pressure stays fairly constant over large variations in
> : temperature...
>
>      It's been a long time since I took thermodynamics, but if I recall
> correctly after all these years, the pressure of any gas will increase
> linearly with the absolute temperature if confined to a fixed volume.

Nitrogen is somewhat lighter than oxygen.  The difference may seem trivial
but I've read that the air in the tires of a 747 weighs in the 100s of
pounds (I've heard of Helium being used in some aircraft).  The main reason
for using nitrogen is probably that it's less reactive than oxygen and thus
less likely to affect the rubber at high temperatures.