In Part 1 on 2023-02-04, the restoration team, with the aid of a propane torch, got inside the 1950s vintage Bendix Central Air Data Computer (CADC) and marveled at the 46 synchros, 511 gears, and 820 ball bearings this mechanical computer uses to turn air data from probes on a jet fighter into information for the pilot’s instrument panel, engine control, and weapons systems. But how does it do that? Looking deeper, we begin to see how to add, subtract, multiply, divide, and compute logarithms, exponentials, and square roots with gears, cams, and shafts.
For a more detailed description of the computations performed, the mechanisms that implement them, close-ups of the hardware, and diagrams explaining its operation, see Ken Shirriff’s blog post “Reverse-engineering an electromechanical Central Air Data Computer”. From the information Ken has been able to obtain, he believes these units were used in the F-86, F-101, F-104, F-105, F-106, and F-111 fighters, and the B-58 bomber.