Re: 747 hump

Date:         25 Sep 97 01:39:42 
From:         faurecm@halcyon.com (C. Marin Faure)
Organization: Northwest Nexus Inc.
References:   1 2 3
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In article <airliners.1997.2235@ohare.Chicago.COM>, michael piersdorff
<piersdorff.michael@ic.gc.ca> wrote:

> jf mezei wrote:
> > But if the hump actually reduces drag, how come other Boeing planes
> > which were designed afterwards (767,777) don't have a hump too ?
>
> The 747 was designed to the same spec that the C-5 was: it had to have a
> through cargo capability (ie. open doors both front and back).  Boeings
> designers chose to accommodate the cockpit in a hump, which is why it's
> there.

Actually, if you look at the models of the C-5 design submitted by Boeing,
there is no hump on it.  It in fact is very similar in appearance to the
Lockheed C-5.  While the 747 benefitted greatly from the design and
aerodynamics studies that were done previously on the C-5 project, the 747
bears no resemblance to Boeing's C-5 design, which was a high wing, four
engine, no-hump airplane.  It is a common misconseption that the 747
stemmed directly from Boeing's C-5 design.  This is not correct.  The
747's shape stemmed from Juan Tripp's desire to have an interim passenger
plane that would serve his routes until the SST became available.  At that
time, the 747s would be removed from passenger service and put into pure
cargo service.  That's why the hump was included in the design; because
the plane was intended from the outset to spend most of its life as a
freighter.  Of course, the SST project was killed and the 747 remained a
passenger plane, but that's the reason behind the hump.  It is not related
to the previous C-5 design.

C. Marin Faure
  author, Flying A Floatplane