Note from the author: Please upvote https://forums.flightsimulator.com/t/workaround-for-missing-propeller-drag-please/368300

See the "FS2020 Boing 747 AoA stick shaking, approach stall" video at https://youtu.be/MP944N9mpm4

This is no livery, this is a flight model mod. The idea is to make the flight behavior more realistic. The most important detail is a realistic maximum lift-drag ratio (L/D)max. This one change makes many other changes necessary. The second detail is I use gear and flaps drag to have a work around for missing propeller drag and ground effect. Now you can flare your airplane before touch-down.
See http://www.andreadrian.de/FS_2020_sailplanes/ for more of my work for MSFS 2020:
Gliders: SG-38, Aircreations 582SL
Sailplanes: DG-808S, Ka 6E, ASK23
Trainer: Tiger Moth
Seaplane: Grumman Goose G21A
Warbirds: Fokker Dr1, North American P-51D

Flight model modification version 1.14.5.0, date 2021-03-12 based on Salty Simulations https://github.com/saltysimulations/salty-747 mod:

I included "Uwa's lighting mods" from https://uwajimaya.github.io/FS2020/
Uwajimaya, I credit your work!
Pack version 1.13 (Feb 16, 2021)

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 30000 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!

point.0 = 1,   -54,      0,   -15.7,  720, 0, 2,  45, 0.9,  2,   0.5,  9, 8, 0, 220, 250, 2 ; 1,    -5,      0,   -15.7,  720, 0, 2, 60,   0.9,  2,   0.5,  9, 8, 0, 220, 250, 2
point.1 = 1,  -113,    -17,   -16.9, 1500, 1, 2,   0, 1.36, 3,   0.5, 11, 9, 2, 220, 250, 2 ; 1,  -102.5,  -17,   -16.9, 1500, 1, 2,  6.5, 1.36, 3,   0.5, 11, 9, 2, 220, 250, 2
point.2 = 1,  -113,     17,   -16.9, 1500, 2, 2,   0, 1.36, 3,   0.5, 11, 9, 3, 220, 250, 2 ; 1,  -102.5,   17,   -16.9, 1500, 2, 2,  6.5, 1.36, 3,   0.5, 11, 9, 3, 220, 250, 2
point.3 = 1,  -113,      0,   -16.9, 1500, 0, 2,   0, 1.36, 3.5, 0.8, 11, 9, 3, 220, 250, 2 ; 1,  -113,      0,   -16.9, 1500, 2, 2,  0,   1.36, 3.5, 0.8, 11, 9, 3, 220, 250, 2
Reduce taxiing curve radius by reducing the distance steering  wheel to main wheels to 50% of original value. Make the main wheels a true tricycle gear.

wing_incidence = 1.5 ; Wing incidence (DEGREES)
htail_incidence = -3 ; 0 ; Horizontal tail incidence (DEGREES)
"You'll want to leave the horizontal tail Incidence at zero for the moment, this value will be used to set the default trim of the aircraft."
Trimmed for OP with no elevator input.

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.

drag_coef_zero_lift = 0.0268 ; 0.02300
"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." from https://docs.flightsimulator.com/html/Samples_And_Tutorials/Defining_A_Flight_Model.htm
BUT using the Asobo numbers NEGLECTS the impact of "modern flight model" 3D model (virtual windtunnel). Use Aircraft Editor, Debug, Sim Polar VhVs to set (L/D)max (glide ratio) to a realistic value.

cruise_speed = 504 ; 493 ; Knots True (KTAS)
thrust_scalar = 0.85
Adjust thrust_scalar to cruise_speed.

ui_autonomy = 16 ; max duration the aircraft can fly between take-off and landing in (Hrs)
fuel_flow_scalar = 1 ; 0.8 ; Fuel flow scalar
Adjust fuel_flow_scalar to ui_autonomy at 80% LVR. I use Aircraft Editor, Debug, Engines to measure autonomy at ground at 80% LVR.

induced_drag_scalar = 1.5 ; 1
flap_induced_drag_scalar = 1.5 ; 1
"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 ; 0.5
roll_stability = 0.05 ; 0.5
yaw_stability = 0.05 ; 0.5
"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."

fuselage_length = -1 ; 250 ; Nose to tail (FEET)
"To adjust the fuselage surface positions and their dimensions to the visual fuselage of the aircraft model"
Use automatic fuselage_length.

[FLAPS.0]
flaps-position.0 =  0,  -1, 0, 1, 1, 0, 0.22
flaps-position.1 =  1, 285, 1, 1, 1, 0, 0.15   ;  1, 285, 0.1, 1, 1, 0, 0.15
flaps-position.2 =  5, 265, 1, 1, 1, 0, 0.11   ;  5, 265, 0.2, 1, 1, 0, 0.11
flaps-position.3 = 10, 245, 1, 1, 1, 0, 0.065  ; 10, 245, 0.4, 1, 1, 0, 0.065
flaps-position.4 = 20, 235, 1, 1, 1, 0, -0.035 ; 20, 235, 0.6, 1, 1, 0, -0.035
flaps-position.5 = 25, 210, 1, 1, 1, 0, -0.085 ; 25, 210, 0.8, 1, 1, 0, -0.085
flaps-position.6 = 30, 185, 1, 1, 1, 0, -0.15
[FLAPS.1]
flaps-position.0 = 0,   -1, 0
flaps-position.1 = 21, 285, 1 ; 21, 285, 0.1 ; 
flaps-position.2 = 21, 265, 1 ; 21, 265, 0.2 ; 
flaps-position.3 = 21, 245, 1 ; 21, 245, 0.4 ; 
flaps-position.4 = 21, 235, 1 ; 21, 235, 0.6 ; 
flaps-position.5 = 21, 215, 1 ; 21, 215, 0.8 ; 
flaps-position.6 = 21, 185, 1.0
The flaps-position drag depends on flaps angle. Therefore a drag multiplier of 1 is good enough.

drag_coef_flaps = 0.1 ; 0.11860
I adjust flaps drag that full flaps give 50% of the airspeed without flaps.

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.
Nowhere Asobo writes about the importance of (L/D)max (glide ratio) and how to set a proper (L/D)max. For me is a bad (L/D)max value the single most important reason for poor quality of (Asobo) flight models. Let's see what Asobo will do in the next software release!

Note from the author: Please upvote https://forums.flightsimulator.com/t/workaround-for-missing-propeller-drag-please/368300

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747-8i Salty mod + flight model mod

Enhance your flight experience with the 747-8i Salty mod, featuring a detailed flight model modification for a more realistic behavior. This add-on includes adjustments to lift-drag ratios, gear and flaps drag, and more. Explore improved flight dynamics and aircraft performance with this comprehensive modification.

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