Re: Why not a full length upper deck on a 747-600X

From:         young@ftest.gulfaero.com (Jim Young)
Date:         12 Oct 96 02:36:04 
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In article <airliners.1996.1895@ohare.Chicago.COM> Tomas Stephanson,
tomas@medialab.ericsson.se writes:
>Why does Boeing not want to extend the upperdeck the full length of
>the aircraft, is it not economical, aerodynamic, weight penalty?

The really big reason is aerodynamics.  A little things called area rule
(look it up in any basic aero book or email me if you want an explanation)
plays a big part in the drag of an airplane.  When Boeing originally
streched the 747-200 to the longer upper deck on the -300, the drag of the
airplane actually went down, even though there was more fuselage. So I
doubt if you will see the upper deck on any 747 derivative reaching much
further aft than the leading edge of the wing.

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Jim Young                  912-965-5243        Fax 912-965-4772
Gulfstream Aerospace       G-V and G-IV Flight Test Engineering
Savannah, GA               "Speed is Life - FlyFast"