Bug with fuel totals?
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Hi guys! I've noticed that there's a discrepancy with the fuel weight shown in the tablet and also with the fuel shown with the sim weight and balance window
On this screenshot, the tablet shows each tank as having 886lbs for a total of 1772 but the tablet shows the total as being 1,576
Even more confusing, the sim weight and balance shows each tank as having 778 (Not 886 like the tablet says).
see a screenshot here
https://i.postimg.cc/xdZKLMzY/Microsoft-Flight-Simulator-5-13-2024-2-38-51-PM.png
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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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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.
@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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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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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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B Black Square referenced this topic on
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@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
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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-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-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.
@Black-Square I want that update sooo baaaad
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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.
