The XB-47 was one of four design proposals approved by the USAAF in
late 1944. The initial Boeing design was based on the B-29, but post-war
research and captured German data investigating swept wing designs caused a
radical redesign. The new design featured a 35o swept wing and six jet
engines in four nacelles. The basic nacelle design became a standard characteristic
of Boeing designs to the present.
The first B-47 flew in late 1947. More than 1,200 were built and served
with the Strategic Air Command at USAF bases throughout the world. The
Stratojet was removed from operational service in the late 1960's.