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The New Coffee Room

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  3. Slower than the speed of sound

Slower than the speed of sound

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  • 89th8 89th

    You know, how does an airplane even know it’s ground speed?

    Aqua LetiferA Offline
    Aqua LetiferA Offline
    Aqua Letifer
    wrote on last edited by
    #4

    @89th said in Slower than the speed of sound:

    You know, how does an airplane even know it’s ground speed?

    Science is neat.

    Please love yourself.

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    • 89th8 89th

      You know, how does an airplane even know it’s ground speed?

      HoraceH Offline
      HoraceH Offline
      Horace
      wrote on last edited by
      #5

      @89th said in Slower than the speed of sound:

      You know, how does an airplane even know it’s ground speed?

      There's a gage in the cockpit which shows the speed.

      Education is extremely important.

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      • 89th8 89th

        You know, how does an airplane even know it’s ground speed?

        CopperC Offline
        CopperC Offline
        Copper
        wrote on last edited by
        #6

        @89th said in Slower than the speed of sound:

        You know, how does an airplane even know it’s ground speed?

        Especially when there is no ground, over the ocean.

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        • bachophileB Offline
          bachophileB Offline
          bachophile
          wrote on last edited by
          #7

          https://cdn.boldmethod.com/images/blog/lists/2016/12/the-4-types-of-airspeed/tas.jpg
          image.jpeg

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          • taiwan_girlT Offline
            taiwan_girlT Offline
            taiwan_girl
            wrote on last edited by
            #8

            How about those Taiwanese? 555

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            • 89th8 Offline
              89th8 Offline
              89th
              wrote on last edited by
              #9

              So I asked our resident expert, the internet. After an exhausting 12 second search, it seems the groundspeed was NOT know before satellites (GPS). Further, one cool explanation of pre-GPS was:

              Simply put, the pilot notes the time they passed over a landmark on their route. Some time later they would do the same again. Knowing the distance between the two points, and the time taken, a pilot can calculate ground speed…speed = distance/time…either mentally, if the numbers are relatively easy, or by using a computer like this…

              image.png

              CopperC 1 Reply Last reply
              • George KG Offline
                George KG Offline
                George K
                wrote on last edited by
                #10

                "Computer," LOL.

                "Now look here, you Baltic gas passer... " - Mik, 6/14/08

                The saying, "Lite is just one damn thing after another," is a gross understatement. The damn things overlap.

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                • 89th8 89th

                  So I asked our resident expert, the internet. After an exhausting 12 second search, it seems the groundspeed was NOT know before satellites (GPS). Further, one cool explanation of pre-GPS was:

                  Simply put, the pilot notes the time they passed over a landmark on their route. Some time later they would do the same again. Knowing the distance between the two points, and the time taken, a pilot can calculate ground speed…speed = distance/time…either mentally, if the numbers are relatively easy, or by using a computer like this…

                  image.png

                  CopperC Offline
                  CopperC Offline
                  Copper
                  wrote on last edited by Copper
                  #11

                  @89th said in Slower than the speed of sound:

                  before satellites

                  Google has let you down.

                  There was a system known as LORAN. I used it when I first started flying. It was decommissioned in 2010. There were ground-based broadcast stations that were used kind of like GPS. This was widely used in general aviation.

                  There was also inertial navigation, but that was mostly used by astronauts.

                  And sadly, I doubt if the younger generation can deal with an E6B.

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                  • JollyJ Offline
                    JollyJ Offline
                    Jolly
                    wrote on last edited by
                    #12

                    Couldn't WW2 navigators do celestial observations? Could they plot ground speed by that?

                    “Cry havoc and let slip the DOGE of war!”

                    Those who cheered as J-6 American prisoners were locked in solitary for 18 months without trial, now suddenly fight tooth and nail for foreign terrorists’ "due process". — Buck Sexton

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                    • CopperC Offline
                      CopperC Offline
                      Copper
                      wrote on last edited by Copper
                      #13

                      Yes, 2 positions and a clock should do it, your accuracy may vary.

                      1 Reply Last reply
                      • LuFins DadL Offline
                        LuFins DadL Offline
                        LuFins Dad
                        wrote on last edited by
                        #14

                        Virgin Atlantic flight from Dulles to London just did the same thing. Apparently the Gulf Stream is NUTS right now.

                        https://www.flightaware.com/live/flight/VIR22/history/20240218/0410Z/KIAD/EGLL/tracklog

                        https://www.washingtonpost.com/weather/2024/02/18/record-jet-stream-winds-dc-flights/

                        The Brad

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