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

Flight model modification version 1.14.5.0, date 2021-03-13:

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!

lift_coef_flaps = 1.45380
Undo the "flight dynamics bug" workaround.

drag_coef_zero_lift = 0.0271 ; 0.02370
Bring (L/D)max to a realistic value.

drag_coef_flaps = 0.15660
"If the aircraft has flaps you can define the lift and drag coefficients that will be added when the flaps are fully deployed"
BUT because there is no propeller drag in MSFS 2020 therefore artificial increased gear drag is used as no propeller drag workaround.

drag_coef_gear = 0.01 ; 0.00500
"gear drag is usually between 0.005 and 0.01"
BUT I use artificial gear drag as "no propeller drag" workaround. Therefore a higher value.

induced_drag_scalar = 1.5 ; 1
flap_induced_drag_scalar = 1.5 ; 1
"If you have this value, use it. If not, 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 a slow speed. If the value is closer to 1, it will glide very easily at slow speeds."

pitch_stability = 0.05 ; 0.25
roll_stability = 0.05 ; 0.25
yaw_stability = 0.05 ; 0.25
"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."

cruise_speed = 447 ; 455 ; Knots True (KTAS)
[JET_ENGINE]
thrust_scalar = 0.85 ; 0.82
Set cruise speed to Wikipedia documented value.

ui_autonomy = 7 ; max duration the aircraft can fly between take-off and landing in (Hrs)
fuel_flow_scalar = 0.9 ; 0.6 ; Fuel flow scalar
Adjust fuel comsumption to ui_autonomy.

empty_weight_CG_position = -10.1, 0, -1 ; -9, 0, -1 ; Position of airplane empty weight CG relative to reference datum (FEET), z, x, y
Move center of gravity to 27% MAC for easier flare.

point.0 = 1,  27.1, 0,  -9.3,   720, 0, 1.68,  38, 0.555, 2, 0.33, 9,   9.4, 0, 0, 0, 2 ; 1,  27.1, 0,  -9.3,   720, 0, 1.68, 75, 0.555, 2, 0.33, 9, 9.4, 0, 0, 0, 2 ; 
Decrease steering wheel angle for better on ground slow speed maneuvering.

wing_incidence = 2 ; Wing incidence (DEGREES)
htail_incidence = 0.3 ; 0 ; Horizontal tail incidence (DEGREES)
Less (auto) trim needed for design cruise speed Vc level flight.

fuselage_length = -1 ; 123 ; Nose to tail (FEET)
Automatic fuselage_length.

[FLAPS.0]
flaps-position.1 = 10, 215, 1 ; 10, 215, 0.25 ; 
flaps-position.2 = 15, 200, 1 ; 15, 200, 0.5 ; 
flaps-position.3 = 20, 185, 1 ; 20, 185, 0.75 ; 
[FLAPS.1]
flaps-position.1 = 18, 215, 1 ; 18, 215, 0.25 ; 
flaps-position.2 = 22, 200, 1 ; 22, 200, 0.5 ; 
flaps-position.3 = 22, 185, 1 ; 22, 185, 0.75 ; 
Redesign flaps drag to have more flaps drag a intermediate flaps settings and less flaps drag in final position.

crossover_speed = 320 ; Knots Indicated (KIAS) overspeed KIAS?
crossover speed (the speed at which the maximum rolling force from the aircraft’s ailerons and spoilers is just sufficient to counter the rolling force generated by a full rudder hardover; above this speed, a rudder hardover can be weathered with sufficient yoke input, while below this speed, a rudder hardover will cause an immediate loss of control)

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