Gregory's Serveralso strange is that the gear reduction between the coarse and fine synchros appears to be 12:1. that's not really a standard ratio--equipment typically uses 9:1, 18:1, 27:1, or 36:1.
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 I just can't emphasize it enough: jet-age aircraft ran on clockwork. straight up steampunk what with the little brass gears and vacuum tubes and neatly-tied bundles of colorful wire  @tubetime I still find the idea of "landed on the moon wearing mechanical wrist watches" to be kind of strange. @tubetime jet age? I earned my license in 1991 and I still had to use a circular sliding rule (the venerable E6B) on my private and instrument check rides. @tubetime honestly with how modern cars are, i'd be more willing to trust this contraption than something that is 1 30-day period away from the aviaton industry's version of Adobe cloud expiring mid-flight. the anti backlash gearing is a giant pain to deal with. I'm making up a bunch of these springs to hold them in place so I can reinstall gears finally got the "Analog Digital Converter" opened up. it's rather complicated! there are multiple absolute encoder wheels connected with a gear train. since i had the gearbox all opened up i counted more teeth and figured out that the coarse-to-fine synchro ratio is actually 1:11, not 1:12 as i previously thought. @tubetime 1:11 isn't like any encoding altimeters I've seen but I'm still betting on an analog synchro to digital Gillham code converter. @bikerglen the Air Data Computer that Ken has been busy with uses the 1:11 ratio as well. i think this unit is from the same avionics system and is designed to be connected to one of the computer's outputs. maybe altitude. this is going to be a real pain to reassemble. I've put in springs to put tension on the backlash mechanisms. so I got everything lined up and the top plate reinstalled. I just have to pluck out the springs and tape. yep, that was a pain. but it is back together, and I have all the connector pinouts! the potentiometers are not all linear relative to position. fascinating.  @tubetime it's probably difficult to make them completely linear @tubetime its typical to see 'log' pots consist of two or three different gradients like you see on the orange line here. Whats most interesting to me is the 'deadzone' of the green pot I don't think I have seen that before |
@tubetime Would 12:1 imply that clock time or degrees are involved?