Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    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.


    ----- 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"
    > 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.
    > >

    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site