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Glenn’s Computer Museum

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B-29 Central Fire Control Computer

The famous B-29 bomber was a critical factor in ending World War II. It incorporated many technical innovations including a Central Station Fire Control System (CSFC) for its five gun turrets. Prior to the B-29, gun turrets in bomber such as the B-17 and B-24 contained a gunner responsible for aiming and firing the guns in the particular turret. The B-29, however, had four unmanned turrets (the tail gun was still manned) that could be (as shown in the left diagram) controlled from several remote locations: a central sighting station near the tail, a nose gunner station and the tail gunner. The advantages of the CSFC were several: smaller gun turrets (less drag), improved sighting accuracy, easier maintenance, redundancy if a sighting station is incapacitated, improved comfort for the gunners, and so forth.

The CSFC comprised many components (e.g., servo amplifiers, motor generators, sighting heads, the gun turrets themselves), but the critical component was the computer itself, which we have. There was one computer for each of the five sighting stations. Based on information from the sighting station along with the plane's altitude, air-speed, and temperature, the computer calculated the proper aiming of the turret considering ballistic factors (wind and gravity), parallax (offset between gun and sighting head) and the appropriate lead to the target based on range and relative velocity of the target.

Shown here are:

We also have the tester for this computer. Figures 9, 10, and 11 show the tester.