Re: B747 technical questions

Date:         28 Jul 97 01:13:27 
From:         shumaker@eisner.decus.org
Organization: DECUServe
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In article <airliners.1997.1523@ohare.Chicago.COM>, malc@mci2000.com (Malcolm Weir) writes:
> On 13 Jul 97 01:25:50 , Jay Biederman <jbb@seanet.com> caused to appear as
> if it was written:
>
>>Actually the tires are inflated with nitrogen gas. This is because the
>>tire pressure stays fairly constant over large variations in
>>temperature. ...
>
> Hmm...  Given that air is 80% nitrogen, I question the assertion that
> nitrogen maintains a similar volume over wide temperature variations (read:
> it doesn't).

The most common reason for using nitrogen for tire inflation where the
pressure must remain constant or at least predictable for wide
temperature variations (e.g.: racing car tires which routinely exceed
180 F tread temperature) is that bottled nitrogen is _dry_.  It's the
water and water vapor that cause wild pressure increases with
temperature; any dry gas would work as well.  Nitrogen happens to
be widely available and cheap.

Mark Shumaker