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Thread: 2.5 minute marker relevance

  1. #1

    2.5 minute marker relevance

    Hi everyone,

    my old ALT1-C has 2.5 minute markers on the 3 o'clock subdial. I think there is some historical, practical relevance to them but can't find an explanation anywhere.

    The more recent Cs have minute markers which came in I think with the 'London' dial and updated logo.

    Does anyone have any information about the relevance of the 2.5 minute markers (picture of mine below).



  2. #2
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    [QUOTE=SuperRichieM;33181]Hi everyone,

    my old ALT1-C has 2.5 minute markers on the 3 o'clock subdial. I think there is some historical, practical relevance to them but can't find an explanation anywhere.

    The more recent Cs have minute markers which came in I think with the 'London' dial and updated logo.

    Does anyone have any information about the relevance of the 2.5 minute markers (picture of mine below).


    I prefer your dial as it is slightly less clustered, but you cannot go wrong with any ALT1-C. Thanks for sharing.

  3. #3
    I don't have a clue but I'll have a go at guessing. Purely aesthetic reasons. Apparently the original Alt1-C design was based on a Mosquito fuel gauge and the 2.5 minute markers are a fairly close resemblance. I suppose that at a later date someone at Bremont might have thought that with a 30 minute counter, it's fairly impractical to not be able to tell which minute you are at hence the new design dial. Probably wrong but it's a good story!

  4. #4
    Moderator RedsBluesGreens's Avatar
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    Quote Originally Posted by theancientmariner View Post
    I don't have a clue but I'll have a go at guessing. Purely aesthetic reasons. Apparently the original Alt1-C design was based on a Mosquito fuel gauge and the 2.5 minute markers are a fairly close resemblance. I suppose that at a later date someone at Bremont might have thought that with a 30 minute counter, it's fairly impractical to not be able to tell which minute you are at hence the new design dial. Probably wrong but it's a good story!
    I'd agree with that. As you say, the C was designed to replicate (as best they could) the Mosquito fuel gauge - I think they did a good job.

    J.

  5. #5
    Agreed, I think that they did a really good job as well.

  6. #6
    It's been really bugging me so I did some online research last night (my Saturday nights are filled with glamour and excitement!).

    There's one thread that says historically flight navigators plotting aircraft positions prefer to have 5 minute markers on dials for clarity and another thread about WW2 colour sector clocks.

    In RAF Ops Rooms incoming aircraft would be colour coded as either red, yellow or blue with the coloured arrows corresponding on the OpsTable at a succession of 5 minute intervals, later reduced to 2.5 minute intervals as aircraft speeds increased during the end of WW2.

    There is at least some relevance to 2.5 and 5 minute interval timings.

    Buuuut... nothing that directly links to the ALT1-C design!
    Last edited by SuperRichieM; 01-24-2021 at 08:32 AM.

  7. #7
    Moderator RedsBluesGreens's Avatar
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    Quote Originally Posted by SuperRichieM View Post

    There is at least some relevance to 2.5 and 5 minute interval timings.

    Buuuut... nothing that directly links to the ALT1-C design!
    I'll try and ask around at HQ for you Rich, I'm sure someone knows something! That said, the more I think about it, the more I agree that it's likely an aesthetic choice is the reasoning behind it.

    J.

  8. #8
    This is good info. I have been wondering why the 2.5 for years. Mystery solved...almost...maybe?

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