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    Re: B52 Bomber Automatic Astro Compass Teardown
    From: David Pike
    Date: 2019 Dec 17, 04:45 -0800

    Dave Walden you wrote: 


    What's inside a Kollsman Instrument Corporation MD-1 Automatic Astro Compass mechanical analog computer from a B52 Bomber? Part of the star tracker inertial navigation system that calculates the altitude and azimuth.


    Good old analogue, you can nibble away at that to begin to get a rough idea what you’re looking at. My guess is it’s basically a resolver/compounder, initially to point the star sensor at the star and when locked on to feed back heading.  To line the sensor initially you’d need heading, bank and pitch angle, plus either Hc and azimuth, or declination and LHA, depending upon whether the resolver also computed Hc and azimuth.  If it did, you’d also need lat & long.  The synchronous motors and transmitters are to drive the resolver and to send signals to the sensor unit and to the heading dependent navigation and weapons systems.  The voltage generators are probably to provide feedback for damping to swing the sensor into place quickly but without overshooting.  I would guess the outer part of the frame is the roll input/output, and the next innermost would be the pitch input, because without a level centre the rest wouldn’t make much sense; output to the sensor must also allow for pitch and roll.  The centre doesn’t have to be truly level of course; it’s all relative.  The can probably dropped into a frame vertically.  The device does what the navigator does using a periscopic sextant, see photo, but instead of the navigator reading off the heading when he takes a sight, the device sends a continuous synchronous heading to the ‘system’.

    The metal tape might be some sort of a ‘solver’ to produce a mathematical function.  In H2S radar there was one in the ‘triangle solver’ which along with a height input converted a plan range to a slant range or vice versa.  It really did make the hypotenuse of a triangle which produced a voltage from a potentiometer to insert a plan range marker into slant range radar returns.  That’s not what it’s being used for here of course, but it might be to solve some other problem.  DaveP

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