The Norden Bombsight
 

NORDEN M-9 BOMBSIGHT
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The Norden bombsight was crucial to the success of the U.S. Army Air Forces' daylight bombing campaign during World War II. Initially developed by Carl Norden for the U.S. Navy, the Army Air Corps acquired its first Norden bombsight in 1932. Highly classified, it gave American forces bombing accuracy unmatched by any other nation at the time.

Initially, production of the Norden bombsight lagged, forcing the rapidly expanding Army Air Forces to use the less accurate Sperry S-1 bombsight. By 1943, however, enough Norden bombsights had become available, and production of the S-1 ended.

The Norden bombsight functioned as a part of a whole system. As the bomber approached its target, the bombardier entered data about wind direction, airspeed and altitude into the bombsight's analog computer, which calculated wind drift and provided the correct aim point. An internal gyroscope provided the stability necessary for using the telescopic sight at high altitudes. When connected to the Sperry C-1 Autopilot, the Norden bombsight provided unprecedented accuracy.

Although newspapers at the time claimed it was so accurate that it could "drop a bomb into a pickle barrel," the Norden bombsight seems archaic by the standards of today's U.S. Air Force. On the famous bombing raid against the ball-bearing factories at Schweinfurt in October 1943, the 8th Air Force sent more than 250 B-17 bombers to destroy the target. The bombardiers used Norden bombsights, but only one of every 10 of their bombs landed within 500 feet of their target. As a result, despite paying the high price of 60 bombers and 600 aircraft, the raid failed to completely destroy the target, and additional bombing raids were needed. By contrast, modern precision guided munitions are accurate to within a few feet, making a single airplane more effective than the hundreds of bombers of WWII.

Check out this site for details of the Norden sight.

http://www.twinbeech.com/norden_bombsight.htm

Re: The Norden Bombsight
 

For those of you interested in the C-1 autopilot I recommend very interesting article by Gerard E. Nistál. That five-page article was under the title of "Electronic autopilot type C-1" and it was published in the Air Tech monthly, Vol. 5 No. 2, August 1944.