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    Re: Traditional navigation by slide rule
    From: Bob Goethe
    Date: 2016 Oct 18, 14:28 -0700

    Good idea, Brad.  I should have thought of this myself, but didn't.

    I am attaching a 100%-scale copy of the current design that should be sufficient for folks to make cardboard prototypes, just as I have.  The design is precisely 11.0" wide, so I have attached two versions:  one on letter size (since many of us ONLY print to letter sized paper) and one for legal sized (which will exhibit no clipping at the edges of the design).

    You will notice that there is a priority given to displaying tangent scales, which all appear both on the slide and on the body of the rule.  I have optimized the design for the Bygrave equations. By this I mean:

    If you look on page 2 of the attached document, representing the reverse of the rule, you will see that in the section called "Great Circle Calculations", equations 1, 4, and 5 all yield results that are tangent values. 

    I found that getting the tangent scales onto the body of the rule let me minimize the amount of slide movement required to solve these particular equations.

    I do welcome further feedback! 

    I never expect to make finished rules except on a by-demand-only, one-by-one basis (which will keep the unit price high, I realize).  The benefit here is that I don't expect to get stuck with a box of unsold inventory at any time.  That said, it would be great to have the design further refined before committing to the fabrication of even the first rule.






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