The Radical Stratojet
 
 
The sleek, swept-wing Boeing B-47 Stratojet is  unquestionably    
the most commercially important aircraft in history.  This
high-performance plane established a lineage of jet aircraft that
has been a multi-billion-dollar bonanza both to the Boeing 
Corporation and to the United States.  The B-47's success led to
the revolutionary Boeing 707 and its many offspring. 
 
The B-47 saga started in 1943 when the United States realized
that Germany and Great Britain had begun to manufacture jet
fighters. By April, 1944, the Air Force issued specifications for
a jet bomber with a top speed of 500 mph.  Five companies offered
designs, ranging from the straightforward North American B-45 to
the radical Boeing XB-47.
 
The XB-47 first flew on December 17, 1947, the 44th anniversary
of the Wright Brothers' flight at Kitty Hawk.  Boeing took a huge
design risk when they developed the XB-47.  The prototype plane
included both a wing swept back 35 degrees and six jet engines
attached to the wings with pods.  This arrangement of engines was
necessary to avoid interference with airflow over the very thin
wings.  These pods also offered better weight distribution, made
maintenance easier, and had positive effects upon the plane's
stall characteristics.  As a weapon system, the B-47's success
depended upon two innovations -- in-flight refueling and new
radar bombing and navigation systems.
 
Structurally, the B-47 was a tremendous advance over any previous
bomber.  The enormous wing had a 9.3 to 1 aspect ratio, which
contributed to its sailplane-like gliding qualities and
extraordinary flexibility.  The B-47 wing could warp 17-1/2 feet
from wingtip to wingtip.  Pilots were sometimes disconcerted to
see the wings twisting up and down.  This same flexibility led to
a smooth ride in turbulent weather.  Boeing's $13,000,000 gamble
on the XB-47 paid off beyond anyone's wildest imagination -- and
continues to do so.