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  • Peter
    Moderator
    • Jan 2000
    • 12507

    What is this???

    Anyone have an idea on this item? I want to say Nav protractor but I can't seem to fnd anything like it online??
    Attached Files
    Cheers,Peter
    "Merlins always drip oil, when they don't....worry!"
  • Moggy C
    Moderator
    • Jan 2000
    • 20534

    #2
    Well it's certainly a protractor, but aviation nav? I doubt it.

    Reason for my doubt is the 1:500 scale noted on the 'ruler' part. Useless for flying, even slow-bimbling spam-cans won't use anything less than 1:250,000.

    At 1:500 a trip to Berlin would need so many charts on board they'd have to leave the bombs at home.

    Moggy

    EDIT: However it looks like the ruler bit gives 4cm (from the white rule) = 20 somethings. If the somethings are nautical miles, then that isn't far off 1:800,000.
    Last edited by Moggy C; 13th February 2015, 15:53.
    "What you must remember" Flip said "is that nine-tenths of Cattermole's charm lies beneath the surface." Many agreed.

    Comment

    • Peter
      Moderator
      • Jan 2000
      • 12507

      #3
      It was found at a crash site Moggy raf bomber..
      Cheers,Peter
      "Merlins always drip oil, when they don't....worry!"

      Comment

      • Moggy C
        Moderator
        • Jan 2000
        • 20534

        #4
        As I have said, I really don't know. Just trying to think it through.

        Notice that it would be useless for navigating to the West as it only has angles from 0-180 degrees, which kind of misses out 180 - 360

        I am coming round to part of a sextant.

        Moggy
        "What you must remember" Flip said "is that nine-tenths of Cattermole's charm lies beneath the surface." Many agreed.

        Comment

        • jeepman
          infrequent poster now
          • Apr 2004
          • 1982

          #5
          Would an item of British origin show Met (presumably for Metres) like that?

          And wouldn't an issue item have an A(Crown)M stamp and a date?

          Even this little steel ruler I still use has a stores or pattern reference number and date

          Click image for larger version

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          Last edited by jeepman; 13th February 2015, 17:15.
          JM

          Comment

          • WV-903.
            Rank 5 Registered User
            • Oct 2007
            • 568

            #6
            What an interesting bit of kit. First thing that comes to mind is it is like a school room protractor of modern times, but this being made of wood suggests earlier times. Could it be WW1 ? It does cover the rest of a compass circle round to 360 Degrees, but I guess you hold pencil in that small notch in centre and swivel the thing to where needed. So I'd say definitely used on Naval or early flying charts. I've never seen one of these wooden items before. If this was found at an RAF Bomber crash site, that means WW2 and who is to say what RAF Bomber navigators carried with them in their bags. The Nav who then may have used this one, must have had his reasons. (then again, I could well be way out wrong -lol . )

            Bill T.

            Comment

            • L4x2
              Rank 5 Registered User
              • Jun 2011
              • 471

              #7
              Some similar things:

              http://www.ebay.com/itm/Antique-Vint...-/151175744680

              https://www.etsy.com/listing/5615136...actor-drafting

              http://antique-scientific-instrument...ctor-p-13.html

              Comment

              • L4x2
                Rank 5 Registered User
                • Jun 2011
                • 471

                #8
                more:

                http://www.kriegsendemilitaria.com/p...ase-protractor

                it appears to be a protractor with a set of "diagonal scales" along the bottom

                http://cifo.in/uploads/6-diagonal%20scales%20MKS.pdf

                Comment

                • L4x2
                  Rank 5 Registered User
                  • Jun 2011
                  • 471

                  #9
                  Diagonal scales being a way to more accurately measure things on a scale map and works in a similar way to a vernier scale.
                  eg to measure 14.6 on that scale you'd measure between the vertical "10" line and where the "4" line indicated on the bottom meets the "6" horizontal line.

                  I'm guessing Met is metres, since 10 units on the scale is 2 cm long and 2cm x 500 = 10 metres
                  Last edited by L4x2; 13th February 2015, 20:21.

                  Comment

                  • L4x2
                    Rank 5 Registered User
                    • Jun 2011
                    • 471

                    #10
                    So the long and the short of it is that it's a protractor with a rule at the bottom for reading distances in metres on a 1:500 scale.

                    It's presence in a crash site could be coincidental, or someone might have been using it just for the protractor part as 1:500 is a bit small. On the other hand 1:500 metres is 1:500000km or half mil which is a bit more aviationy

                    Comment

                    • Flyer
                      Rank 5 Registered User
                      • Nov 2008
                      • 335

                      #11
                      During my childhood EACH schoolboy/schoolgirl in our country was required to have such protractor in his/her schoolbag. Those individual protractors had size about one half of palm of the hand, and were made of tin-plate (most part of them) or aluminium (minor part). Later there were used - and are in use today - plastic protractors.
                      And each mathematical classroom in each school has large version of protractor with size like the 19'' computer display. Those large protractors were used for demonstration purposes and were made of hardboard with wooden parts.

                      Comment

                      • Peter
                        Moderator
                        • Jan 2000
                        • 12507

                        #12
                        Thanks guy's i have never seen one like this before...
                        Cheers,Peter
                        "Merlins always drip oil, when they don't....worry!"

                        Comment

                        • TonyT
                          Rank 5 Registered User
                          • Oct 2006
                          • 9023

                          #13
                          https://cdn.shopify.com/s/files/1/01...g?v=1393114156

                          http://kriegsendemilitaria.com/colle...ase-protractor

                          Left at the crash site by a member of the recovery team?
                          Last edited by TonyT; 14th February 2015, 11:55.

                          Comment

                          • Peter
                            Moderator
                            • Jan 2000
                            • 12507

                            #14
                            So they werent british then?
                            Cheers,Peter
                            "Merlins always drip oil, when they don't....worry!"

                            Comment

                            • Moggy C
                              Moderator
                              • Jan 2000
                              • 20534

                              #15
                              Metres have never been used in British aviation to my knowledge.

                              Moggy
                              "What you must remember" Flip said "is that nine-tenths of Cattermole's charm lies beneath the surface." Many agreed.

                              Comment

                              • Peter
                                Moderator
                                • Jan 2000
                                • 12507

                                #16
                                Thanks Moggy...
                                Cheers,Peter
                                "Merlins always drip oil, when they don't....worry!"

                                Comment

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