Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Flying to Antarctica
    From: Antoine Couëtte
    Date: 2019 Jan 21, 16:41 -0800

    RE : Flying-Antarctica-Morris-jan-2019-g44044

    Hello Brad,

    " I am not quite sure what they mean by "true direction".  Is that the instantaneous course on the standard latitude/longitude globe?   I think so. ": Yes, True direction is a direction referenced to the geographical North.

    My reference states that the grid system simplifies in that the wind direction remains constant. " : This statement needs clarification. As long as the high altitude winds follow a great circle track - which may often be [approximately] the case on rather short distances (e.g. up to 1,000 NM), but not always since jetstreams sometimes sharply "turn" generating [strong] Clear Air Turbulence - then the "grid wind direction" remains constant since on the Aircharts used for transpolar navigation any Great Circle is very close from a straight line. Since straight lines cross the airgrid at the same angles, then - yes - the grid wind direction remains [approximately] constant.

    Best Regards,

    Kermit

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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