In order to meet the USAAC's 1940 requirements for a "superbomber",
the Superfortress used a narrow chord, highly loaded wing, a pressurized cabin,
and remotely controlled gun turrets. First flown on September 21 1942, B-29
Superfortresses were used to drop the two atomic
bombs on Hiroshima and Nagasaki that ended World War II.
After World War II, an improved B-29 went into
service designated the B-50.
The first post-war Russian bomber, the Tu-4
Bull, was a direct copy of the B-29.