THE NORDEN BOMB SIGHT & C-1 AUTOPILOT
The Norden bombsight is arguably one of the most important technological advancements to come out of WWII. Even though Carl Lucas Norden had built a prototype and was developing his bombsight well before, it was its use during WWII which made it famous. Even today people still marvel at the super secret Norden Bombsight. PHOTOS HERE COURTESY OF http://www.twinbeech.com/
This is a close up of the bombsight head pictured above. The sight head contains the computer which calculates the point in space where the bombs will be released. Below the rubber eyepiece is the optics cradle which the bombardier sights through. The optics cradle is connected to a gyro which keeps the optics stabilized with reference to the ground.
The Norden bomb sight is made up of two principal parts; the sight head (pictured above) and the stabilizer (pictured below) which the sight head mounts on top of. The stabilizer is also part of the autopilot (SBAE, AFCE and C-1type auto pilot) and has a gyro that senses deviation about the yaw, or vertical axis of the airplane. The stabilizer is an essential part of the autopilot and will function without the sight head installed.
Many people know about the bomb sight head but few seem know that the stabilizer is required for the bomb sight to function and to be complete. You may have a sight head but in order to have a complete bomb sight you will need the stabilizer. The stabilizer was usually mounted to some form of vibration isolating bomb sight mount. Sometimes the bombsight mount was made by the aircraft manufacturer such as in the PBY Catalina, TBM Avenger and other Navy aircraft. The Army seems to have used a standardized mount in its aircraft. The early war mount was usually some form of the B-6 mount, which was later replaced by the B-7. The B-7 mount is the typical mount used in all of the mid to late war Army aircraft like the B-24, B-17G, A-26 and the B-25.
When pilots had trouble flying with enough precision to keep the Norden bombsight accurate, Honeywell engineers were asked to help solve the problem, drawing on their expertise in home heating technology. A household heating thermostat is a feedback control device. It senses changes in temperature and turns on the furnace if it gets too cold. Once the temperature has returned to the proper degree the thermostat turns the furnace off. These same principles were used in the development of the airplane autopilot.
The engineers developed a device that would automatically correct the movement of an airplane that flew off course. This device became known as the C-1 autopilot. The key to the system was a gyroscope that could sense variations in course and speed and make adjustments well before a human pilot. Once the autopilot was turned on, control of the airplane passed to the bombardier, who would make final flight changes as he peered through the Norden bombsight. The C-1 autopilot made it possible to achieve flight accuracy beyond human ability, and its success launched the new "Aero" division of Honeywell.