Update! MSFS2020 - Cessna 208B Grand Caravan EX Improvement Mod - V.

Flight model modification version V.

Compatible to MSFS version Include Uwa's lighting mods when available.

MSFS 2020 version aka WU3 had the "Flight dynamics bug". Hotfix undid this bug. But version did change the CD,0 to (L/D)max relation, too. This change was not undone with version
Using the parameters drag_coef_zero_lift, htail_incidence, thrust_scalar and fuel_flow_scalar the maximum airspeed, (L/D)max and fuel consumption can be set to one operating point OP. I set the OP to no flaps, retracted landing gear, full thrust, level flight, no elevator input and altitude 20000 ft.

I use the MSFS 2020 documentation from https://docs.flightsimulator.com/html/Samples_And_Tutorials/Defining_A_Flight_Model.htm Citations are in "". Asobo has expanded the documentation, but sadly the documentation is still far away from complete. Asobo please go on!

To all critics of my work: First, I am an armchair pilot. If you only accept flight model mods from real life 4 stars pilots, don't use it. Second, if you think my mod is atrocious, don't use it. To everybody else: The mod is the best I can do with my knowledge of MSFS 2020. Stay happy and healthy!

empty_weight = 5310 ; 5150 ; Empty weight, (LBS)
cruise_speed = 186 ; Knots True (KTAS) at 20000 ft
Use Cessna 208B "Grand Caravan EX" Technical Data. 

point.0 = 1,   14.5,  0,    -5.38,  750, 0, 0.596, 45, 0.461, 2, 0.952, 4.8, 4.8, 0, 184, 184, 2 ; 1,   14.5,  0,    -5.38,  750, 0, 0.596, 30, 0.461, 2, 0.952, 4.8, 4.8, 0, 184, 184, 2
Smaller taxiing curve radius.

wing_incidence = 0 ; Wing incidence (DEGREES)
htail_incidence = 2.2 ; 1 ; Horizontal tail incidence (DEGREES)
No elevator input needed for level flight at full thrust at sea level.

elevator_trim_neutral = 0 ; 1 ; Elevator trim max angle (absolute value) (DEGREES), for indicators only (no influence on flight model)
I want to have the green area in the middle of VSI.

lift_coef_flaps = 0.4861 ; 0.97220
This is NOT the "flight dynamics bug" workaround. The flaps lift is just too exaggerated for my taste.

drag_coef_zero_lift = 0.0758 ; 0.03790
"this value is usually of around 0.02 to 0.025 for an aircraft with a glide ratio above 15, 0.03 to 0.04 for aircraft with glide ratios of about 10, and up to 0.1 for some slow bush planes with very low glide ratios."
I use Aircraft Editor, Debug, Sim Polar VhVs to set (L/D)max (glide ratio) to a realistic value. And the correct value is 2 times the Asobo value. Do we have another Asobo times 2 bug?

thrust_scalar = 1.9 ; 1.05 ; Propeller thrust scalar
More drag_coef_zero_lift needs more thrust_scalar for the same cruise_speed.

ui_autonomy = 7 ; max duration the aircraft can fly between take-off and landing in (Hrs)
fuel_flow_scalar = 0.67 ; 1 ; Fuel flow scalar
More thrust_scalar needs less fuel_flow_scalar for the same ui_autonomy at 80% LVR.

induced_drag_scalar = 1.5 ; 1.15
flap_induced_drag_scalar = 1.5 ; 1.15
"a value between 1.2 and 1.5 is usually fine. If this value is above 1.5, the plane will generate a lot of drag at slow speed, and if the value is closer to 1, it will glide very easily at slow speeds."

pitch_stability = 0.05 ; 0.1
roll_stability = 0.05 ; 0.1
yaw_stability = 0.05 ; 0.1
"You need to enter a value that is higher than zero for backwards compatibility with the legacy flight model, and you can enter 0.01 - for example - if you want only the minimum friction. If the plane has more inertia, you can enter higher values."

rudder_engine_wash_on_roll = 2.0 ; Torque effect
Not documented parameter.

drag_coef_flaps = 0.14 ; 0.08990
"gear drag is usually between 0.005 and 0.01"
BUT because there is no propeller drag in MSFS 2020 therefore artificial increased gear drag is used as no propeller drag workaround.

flaps-position.0 = 0, -1, 0
flaps-position.1 = 15, 150, 1 ; 15, 150, 0.5
flaps-position.2 = 30, 125, 1
flaps-position drag depends on flaps angle. Therefore drag multiplier of 1 is good enough.

Summary: "If Asobo only knew what Asobo knows". Some Asobo engineers write documentation and tell everybody what to do and why. Other Asobo engineers write cfg files. As you can see above, these two groups don't talk to each other. Specially not about the induced_drag_scalars and stability parameters.
That Asobo nowhere writes about the importance of (L/D)max (glide ratio) and how to set a proper (L/D)max value is for me the single most important reason for the poor quality of Asobo flight models. Let's see what Asobo will do in the next software release!

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