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    Re: ball drop sextant report, 1949
    From: Robert Eno
    Date: 2006 Sep 20, 21:18 -0500

    I have a ball drop sextant in my collection, along with the operation
    manual. It includes the principle of operation. I can scan it in for anyone
    who wants to have a look.

    It is a cumbersome piece of gear and I honestly cannot figure out why or how
    the designers believed that this would be a workable instrument.

    Robert

    ----- Original Message -----
    From: "Paul Hirose" <cfuhb-acdgw@earthlink.net>
    To: "Google nav list" <NavList@fer3.com>
    Sent: Wednesday, September 20, 2006 12:45 AM
    Subject: [NavList 1304] ball drop sextant report, 1949


    >
    > In the U.S. Dept. of Transportation archives I found a 1949 Civil
    > Aeronautics Administration report on a new aircraft sextant of the "ball
    > drop" type, developed by the U.S. Naval Observatory. The CAA tested it
    > against a conventional Pioneer bubble sextant, best known by its
    > military designation AN5851-1 or A-14.
    >
    > The ball drop sextant performed poorly. "The only possible conclusion to
    > be reached from the flight tests is that the ball drop sextant fails by
    > a great deal of attaining the accuracy necessary for celestial
    > navigation in the air."
    >
    > Unfortunately, the report does not go into its principle of operation
    > much beyond "the ball drop sextant uses the line of fall of a small
    > steel ball to establish a vertical line".
    >
    > You will have to navigate to the page. My attempts to create a clickable
    > link have failed, probably due to the way Javascript is used at the
    > site. Also, if you have Internet Explorer's security settings turned up,
    > it will be necessary to add the site IE's list of trusted sites.
    >
    > http://dotlibrary.specialcollection.net/
    >
    > Click "FAA and CAA Research Reports"
    > Click "CAA TECHNICAL DEVELOPMENT REPORTS"
    > Then look for the ball drop sextant report (the browser Search function
    > will find it if you enter "sextant").
    > The page has an small portion of the report, and a link to download a
    > PDF scan of the whole thing, which is about 1.2 MB.
    >
    > --
    > I block messages that contain attachments or HTML.
    >
    >
    >
    >
    >
    > >


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