Re: Airliner Windows

Date:         06 Sep 97 02:55:07 
From:         don@toyunix.zl2tnm.gen.nz (Don Stokes)
Organization: The Wolery
References:   1 2 3
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In article <airliners.1997.2002@ohare.Chicago.COM>,
Stephen H. Westin <westin@graphics.cornell.edu> wrote:
>"Patt" <real-address@bottom.net> writes:
>> The size of the windows is proportional to pressurization differential
>yes...
>> for structural safety reasons...
>no.
>> ie: the Concorde has smaller windows (higher
>> differential), than a Boeing airplane (7 1/2 - 8 psi)
>
>But I believe this has to do with depressurization rates if a window
>blows. According to Brian Calvert's lovely little book on the
>Concorde, anyway. It seems that there are regulations pertaining to
>how fast the air is lost vs. time to reach a breathable altitude, etc.

For subsonic airliners the issue is structural -- eg the DC-8 has bigger
windows than other airliners in the same class, but there are fewer of
them, so all up there's about the same amount of metal stopping the
thing coming unzipped.  Also compare the F-27 and F-50 -- the latter
has "normal" sized windows, whereas the F-27 has quite large round windows,
but fewer of them.  (One of the reasons I liked the F27, back when they
flew regularly in NZ.)

Actually, I think the issue with Concorde isn't so much keeping air in
so much as not having it rush out too quickly and doing structural damage.
Concorde not only has to shed 2-3 times as much altitude as a subsonic
airliner to get to a breathable pressure, but has to kill 2/3rds of its
speed as well -- difficult to do in a dive.  I'm pretty sure the pressure
will have equalised through a window-sized hole long before the aircraft
reaches such an altitude.

-- don