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    Weight and Balance

    PA-28R Arrow III
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    • RetiredMan93231
      RetiredMan93231 last edited by RetiredMan93231

      This aircraft appears to be inherently out of balance and is slightly right wing heavy. The optimal loading to achieve the best weight and balance is as follows:

      Pilot - 170 lbs
      Copilot - 130 lbs
      Luggage - 100 lbs

      Fortunately, I have my default pilot set to male and copilot set to female in MSFS... so this loading is also very realistic.

      1 Reply Last reply Reply Quote 2
      • Martyn
        Martyn JF Staff last edited by

        Thanks for the feedback. Our flight dynamics expert is looking into this to see if any changes are required to improve realism.

        Martyn

        RetiredMan93231 1 Reply Last reply Reply Quote 1
        • RetiredMan93231
          RetiredMan93231 @Martyn last edited by

          @Martyn, Thanks for looking into this... I noticed that in the flight-model.cfg file the Pilot and Copilot lateral locations are slightly different, but they are not mis-matched enough to account for a 40 lb. weight imbalance.

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          • RetiredMan93231
            RetiredMan93231 last edited by RetiredMan93231

            @Martyn,

            After more investigation, it seems that the weight and balance of the aircraft is not the actual problem... Reducing the copilot weight is only compensating for the real problem, which is the configuration of the engine_wash_on_roll parameter in the flight-model.cfg file. There is a duplicate entry for this parameter which first sets it to 1, followed by another entry that resets it to 0. The results of this setting is a slow right roll that looks like a weight imbalance.

            Editing these settings as shown below results in wings level cruise flight with no slip, using a balanced payload (170 lb. Pilot and 170 lb. Copilot)...

            [FLIGHT_TUNING]
            engine_wash_on_roll =0.7 ;1
            ;engine_wash_on_roll =0

            S 1 Reply Last reply Reply Quote 3
            • Martyn
              Martyn JF Staff last edited by

              @RetiredMan93231 said in Weight and Balance:

              engine_wash_on_roll

              Thanks, I'll pass that info to our flight dynamics creator!

              1 Reply Last reply Reply Quote 2
              • R
                RaulKO last edited by

                Just to let you guys know that I made the corrections to the flight model and the aircraft handling in the ground improved considerably, being able to keep the plane nose at the centerline during all the take off run...

                ghrasko 1 Reply Last reply Reply Quote 0
                • ghrasko
                  ghrasko @RaulKO last edited by

                  @RaulKO, are you using the suggested 0.7 value? Is it related to pilot - copilot situation @RetiredMan93231 has mentioned, or a generally good value?

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                  • S
                    sluflyer06 @RetiredMan93231 last edited by

                    @RetiredMan93231 said in Weight and Balance:

                    @Martyn,

                    After more investigation, it seems that the weight and balance of the aircraft is not the actual problem... Reducing the copilot weight is only compensating for the real problem, which is the configuration of the engine_wash_on_roll parameter in the flight-model.cfg file. There is a duplicate entry for this parameter which first sets it to 1, followed by another entry that resets it to 0. The results of this setting is a slow right roll that looks like a weight imbalance.

                    Editing these settings as shown below results in wings level cruise flight with no slip, using a balanced payload (170 lb. Pilot and 170 lb. Copilot)...

                    [FLIGHT_TUNING]
                    engine_wash_on_roll =0.7 ;1
                    ;engine_wash_on_roll =0

                    How extensively have you tested to make sure this doesn't have impacts in other areas of the envelope? I like what you've found for improving the take-off roll, but what all does this value effect in other phases of flight, is it perhaps negatively impacting the work JF has done on making the aircraft fly correctly? I'm just trying to create conversation because sometimes a good thing in 1 place is a bad thing elsewhere...

                    ghrasko 1 Reply Last reply Reply Quote 0
                    • ghrasko
                      ghrasko @sluflyer06 last edited by

                      @sluflyer06 That is a good question. Anyhow there is a clear error in the official config file now, as the attribute exists twice with different values:

                      [FLIGHT_TUNING]
                      engine_wash_on_roll =1
                      engine_wash_on_roll =0
                      

                      As a software specialist, my assumption is that with this setting the result is that the parameter's actual value will be 0. Which is probably not the intention of JF.

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