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

From:         "P. Wezeman" <pwezeman@blue.weeg.uiowa.edu>
Organization: The University of Iowa
Date:         21 Oct 96 02:29:18 
References:   1 2
Followups:    1
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On 12 Oct 1996, Jim Young wrote:

>
> 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.

   Would this mean that if, say, the Boing 757 were to be enlarged to carry
more passengers that there would be less drag if instead of extending the
fuselage fore and aft with the existing cross section, the fuselage was
made double deck in front of the wings and extended single deck aft of the
wings so as to maintain weight and aerodynamic balance? In other words,
would the drag reduction from improved area ruling make up for the increased
cross sectional area? I realize that the complexity of doing this and
getting it certified compared to a simple stretch job could easily make
it impractical even if there were performance advantages. Also, the ratio
of passenger seats to cargo space would be changed, although if cargo
space were important, a carrier would probably not be using a B757.

                        Peter Wezeman, anti-social Darwinist

                             "Carpe Cyprinidae"