The Martin B-10 was the first all-metal monoplane bomber to go into regular use by the United States Army Air Corps, entering service in June 1934. It was also the first mass-produced bomber whose performance was superior to that of the Army's pursuit aircraft of the time. The B-10 began a revolution in bomber design. Its all-metal monoplane build, along with its features of closed cockpits, rotating gun turrets, retractable landing gear, internal bomb bay, and full engine cowlings, would become the standard for bomber designs worldwide for decades. At the time of its creation, the B-10B was so advanced that General Henry H. Arnold described it as the air power wonder of its day. It was 1.5 times as fast as any biplane bomber, and faster than any contemporary fighter. The B-10 began a revolution in bomber design; it made all existing bombers completely obsolete. However, the rapid advances in bomber design in the 1930s meant that the B-10 was eclipsed by the B-17 Flying Fortress and Douglas B-18 Bolo before the United States entered World War II. Info: Wikipedia http://en.wikipedia.org/wiki/Martin_B-10 Profiles: American Aircraft Of World War II Published by Chancellor Press Ltd.