World War II Norden Bombsight
Published September 25, 2007
This device for accurately dropping bombs from aircraft was one of the United States' most closely guarded secrets of World War II. It was originally designed for use on U.S. Navy aircraft by Carl Norden, a Dutch engineer educated in Switzerland who immigrated to the U.S. in 1904. The device used a mechanical analog computer comprised of motors, gyros, mirrors, levels, gears, and a small telescope. The bombardier input the necessary information (airspeed, altitude, etc.) and the bombsight would calculate the trajectory of the bomb being dropped.
Near the target the aircraft would fly on autopilot to the precise position calculated by the bombsight and release the ordnance. Using this device, bombardiers could drop their bombs within a 100-foot circle from an altitude of well over 20,000 feet.