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Bug with fuel totals?

Scheduled Pinned Locked Moved Piston & Turbine Dukes
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  • Black SquareB Offline
    Black SquareB Offline
    Black Square
    Black Square Developer
    wrote on last edited by
    #3

    This is because the simulator uses different conversions for fuel weight in different places, and uses only one weight for multiple types of fuel. AVGAS is 6.02 lbs/gal, while jet fuel is 6.75 lbs/gal. I've seen places in the simulator's code where both are assumed to be 6.70 lbs/gal. I use the two correct real world numbers in my code, despite knowing the discrepancy this would cause, because I couldn't get myself to use the wrong numbers.

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    • Black SquareB Black Square

      This is because the simulator uses different conversions for fuel weight in different places, and uses only one weight for multiple types of fuel. AVGAS is 6.02 lbs/gal, while jet fuel is 6.75 lbs/gal. I've seen places in the simulator's code where both are assumed to be 6.70 lbs/gal. I use the two correct real world numbers in my code, despite knowing the discrepancy this would cause, because I couldn't get myself to use the wrong numbers.

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      X Offline
      xender
      wrote on last edited by
      #4

      @Black-Square I see, makes sense. Maybe there should be a note about this in the manual because the manual states you can use both methods to handle the loading of fuel/weight but it doesn't mention anything about the discrepancy.

      In any case, Shouldn't the total shown on the tablet correspond to the sum of both tank values as shown on the tablet too?

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      • Black SquareB Offline
        Black SquareB Offline
        Black Square
        Black Square Developer
        wrote on last edited by
        #5

        It's very likely that I used the native SimVars for the total fuel weight in some places without thinking about this discrepancy. In fact, we can prove that's the case from your screenshot:

        1,772 * (6.00/6.75) = 1,577

        The best I can do for you is to remove all references to the native fuel weight value from the code for all the avionics in my aircraft, which luckily, appears to only occur in the tablets, and only in the once place you've mentioned, according to my search.

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        • Black SquareB Offline
          Black SquareB Offline
          Black Square
          Black Square Developer
          wrote on last edited by
          #6

          All done 🙂 "Fuel on Board" total now matches the total of both tanks as displayed on the tablet.

          Turns out there were two problems at play here, as there so often are. I had also accidentally left the flag for fuel type in the Turbine Duke's configuration files to AVGAS, so that accounts for the rest of the discrepancy with the native payload manager number. The two values should now match with 0.05%, or less than one pound for the Dukes, hopefully a negligible amount unless you're fueling up a 747.

          Thanks for pointing this out! Always happy to drop what I'm doing and make a quick fix.

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            X Offline
            xender
            wrote on last edited by
            #7

            Thank you!

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            • Black SquareB Black Square referenced this topic on
            • H Offline
              H Offline
              hazzer111
              wrote on last edited by
              #8

              I noticed that on sombre if the incorrect max fuel weight is given there. I imagine this is all linked to this, unsure if it is something that someone can rectify or simbrief themselves.

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              • toby23T Offline
                toby23T Offline
                toby23
                wrote on last edited by
                #9

                @Black-Square Can you please confirm that in the flight_model.cfg file, fuel_type = 1 (AVGAS) should read = 2 (Jet-A) for the Turbine Duke. Thank you

                Ryzen 5800X3D, 64GB RAM, RTX 4090, Windows 11

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                • Black SquareB Black Square

                  All done 🙂 "Fuel on Board" total now matches the total of both tanks as displayed on the tablet.

                  Turns out there were two problems at play here, as there so often are. I had also accidentally left the flag for fuel type in the Turbine Duke's configuration files to AVGAS, so that accounts for the rest of the discrepancy with the native payload manager number. The two values should now match with 0.05%, or less than one pound for the Dukes, hopefully a negligible amount unless you're fueling up a 747.

                  Thanks for pointing this out! Always happy to drop what I'm doing and make a quick fix.

                  Black SquareB Offline
                  Black SquareB Offline
                  Black Square
                  Black Square Developer
                  wrote on last edited by
                  #10

                  @Black-Square said in Bug with fuel totals?:

                  I had also accidentally left the flag for fuel type in the Turbine Duke's configuration files to AVGAS,

                  You can expect that one in the next update. Fun fact: PT6 engines are happy to run on AVGAS in a pinch, though it reduces the maintenance intervals of the engine. I've seen many King Air pilots do this at smaller airports near me that don't have Jet-A.

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                  • Black SquareB Black Square

                    @Black-Square said in Bug with fuel totals?:

                    I had also accidentally left the flag for fuel type in the Turbine Duke's configuration files to AVGAS,

                    You can expect that one in the next update. Fun fact: PT6 engines are happy to run on AVGAS in a pinch, though it reduces the maintenance intervals of the engine. I've seen many King Air pilots do this at smaller airports near me that don't have Jet-A.

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                    xender
                    wrote on last edited by
                    #11

                    @Black-Square I want that update sooo baaaad

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                    • T Offline
                      T Offline
                      TreeTops
                      wrote on last edited by
                      #12

                      Is there a reason why the left and right fuel quantities in the Turbine Duke are different?
                      L=138.4 R=132.5

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                      • Black SquareB Offline
                        Black SquareB Offline
                        Black Square
                        Black Square Developer
                        wrote on last edited by
                        #13

                        That's how it is in the real aircraft. I suspect the extra fuel is in the form of a header tank in the left engine nacelle where there is a centralized fuel filler nozzle that gravity feeds to all the other tanks, though I have been unable to confirm this.

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