707 and KC-135 relationship and something about the 747 (was: Subsidies)

From:         shafer@ferhino.dfrc.nasa.gov (Mary Shafer)
Organization: NASA Dryden Flight Research Center
Date:         09 Apr 96 14:22:51 
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According to the then-current Jane's All the World's Aircraft, the
KC-135 prototypes were being built when Boeing decided to offer an
airliner version.  They, Boeing, had to get permission from the USAF
to use the KC-135 R&D rather than develop the 707 completely from
scratch (which would, of course, be impossible--the genie was out of
the bottle, after all).  The USAF also had to grant permission for
Boeing to set up the 707 production line, as it competed with the
KC-135 line for skilled workers.  I verified this in contemporaneous
Flight International articles.  (Fortunately, Dryden has an extensive
collection of past issues and editions of these, making it very

The only significant difference between the two airframes is the
fuselage shape; the KC-135 has a circular cross section, while the 707
has a bi-lobar cross section, with the floor at the intersection of
the two circular lobes.  The 707 fuselage was designed to give
passengers shoulder room, something fuel tanks don't require, and more
baggage space.

Thus, the 707 is, in fact, a KC-135 derivative, rather than the
reverse, although the reverse is very commonly believed.

In addition, the 747 is rather vaguely based on the Boeing entry into
the competition that resulted in the C-5 buy.  The USAF funded the
initial design work for the various paper planes, of course.  However,
there's not a lot of the original remaining in the 747, but they did
do the general calculations for sizing, etc.  However, I would not
really say that the 747 is a derivative of this paper plane, at all,
as so little of the latter survived in the former.

Mary Shafer               NASA Dryden Flight Research Center, Edwards, CA
SR-71 Flying Qualities Lead Engineer     Of course I don't speak for NASA
shafer@ferhino.dfrc.nasa.gov                               DoD #362 KotFR
URL http://www.dfrc.nasa.gov/People/Shafer/mary.html