MSFS flight model when landing

[eric_marciano]

Am I the only one being disturbed by the way the MSFS flight model reacts when landing?

Since the release of MSFS 2020, I noticed this problem and it kept going update after update. The problem is about the behavior of the aircraft when touching down when landing. It always tends to turn left or right, forcing you to apply a strong rudder correction that is not realistic at all. I used to be a private pilot, I flew the Cessna 152, 172, Piper PA-28, Socata TB-9. I also flew professional airline simulators, A320 and CRJ. I never saw such behavior in real life.

You can have crosswind when landing, which will cause this tendency to turn into the wind. I know this, but when this happens you feel the wind deviation before touching down and the behavior on ground is the continuation of the behavior in flight. What I see in MSFS is different: the aircraft flies normally during approach and when you have little or no crosswind, the aircraft still turns left or right as soon as the wheels touch the ground.

I also know about the torque effect when you have a propeller, this is noticed on take off and it is normal, but when landing the engine is idle so the torque effect should be close to 0. In addition, when landing a jet powered aircraft, the torque effect cannot explain this behavior when landing.

 

Did you also notice this?

Do you think it is realistic or is this effect too strong?

 

I recently saw an interview of a real airline captain, saying the flight was realistic except "the very last moment of the flight", I know what he was talking about.

I would be happy to have your opinion about this.

[tiger1962]

Hi Eric, I've also noticed this and I've tweaked a few of the default and some of the payware planes to remove it. You're right about the crosswind (weathervane) and torque effect settings, they are way over the top especially for taildraggers. I highly recommend using the excellent mods available for most of the default planes, and switch all the MSFS Options > Assistance menu settings to "Off".

[eric_marciano]

Thanks for the info, this is interesting. Can you please tell me more about the parameters that need to be tweaked to limit this problem?

I will search for mods that correct this, if you can give me 1 or 2 links that would help.

FYI, I never use any assistance, they are all off.

[tiger1962]

Here's what I do for the weathervane effect:

 

Open your chosen aircraft’s flight_model.cfg file with Notepad and scroll down to the [AERODYNAMICS] section.

Look for the side_force group of entries, there will be four in total:

side_force_slip_angle = -2.12726

side_force_roll_rate = 0.25450

side_force_yaw_rate = 3.09566

side_force_delta_rudder = -1.79189

Copy the value for the first entry, e.g. -2.12726, and paste it into Calculator.

Now divide by 4. Copy the result and paste it back into your flight_model.cfg like so:

side_force_slip_angle = -0.531815 ; -2.12726

The ; between the two values is there to retain the original value while making it inactive.

Repeat this process for the other three values.

Now look for the yaw_moment group of entries, there will be eight in total but we’re only editing two of them:

yaw_moment_yaw_damping = -16.27597

yaw_moment_delta_rudder = 0.64763

Copy and paste the yaw_damping value into Calculator and divide by 2:

yaw_moment_yaw_damping = -8.137985 ; -16.27597

Copy and paste the delta_rudder value into Calculator and multiply by 2:

yaw_moment_delta_rudder = 1.29526 ; 0.64763

 

For the torque effect, scroll down to the [FLIGHT_TUNING] section.:

torque_on_roll = 1

engine_wash_on_roll = 1

rudder_engine_wash_on_roll = 7

Divide each figure by 2 to recude the effect by half:

torque_on_roll = 0.5 ; 1

engine_wash_on_roll = 0.5 ; 1

rudder_engine_wash_on_roll = 3.5 ; 7

 

Links for the most outstanding default aircraft mods I use are below:

 

FlyByWire sim A32nx project: https://flybywiresim.com/

 

MrTommyMxr's DA62 Improvement Project: https://flightsim.to/file/2733/da62x-project

 

MrTommyMxr's DA40NG Improvement Project: https://flightsim.to/file/2738/da40-ngx-project

 

CaptMatto's Bonanza G36 Improvement Project: https://flightsim.to/file/21221/bonanza-g36-improvement-project

 

Dakfly's Citation Longitude Project: https://flightsim.to/file/3655/asobo-cessna-citation-longitude-flight-dynamics-modifications-project-version-1-0

 

JPLogistics C152 mod: https://github.com/JPLogistics/JPLogistics_C152/releases

 

One of my own attempts in the library here:

 

Edited September 2, 2022 by tiger1962

[chicagorandy]

Thanks a bunch for sharing your expertise Tim. You are among the group of great folks who make this site the valuable resource it is.

[rrroberttt]

Thank you very much for this. It is very useful.

 

Robert

[nsproles]

Will mandatory updates overwrite these changes, necessitating doing them again?

[davidc2]

Will mandatory updates overwrite these changes, necessitating doing them again?

 

Yes. Which is why I keep a text file with the changes on my desktop, including instructions on what file to change etc.....

[nsproles]

Thanks.

[piet06273]

First, due to lasting insane GPU fever in my country my system is still not up to an adequate presentation of MSFS. The following is only my personal interpretation of whats happening. As I see it there is a sudden and abrupt change in the Sim after touchdown. When flying the plane is free and seperated from the 'Earth' The (ground)scenery and the aircraft are two different things that are displayed simulaniously but do not phisically interact with each other. Then on (stabilized) approach close to the ground at about 30ft you see the plane gradually entering the ground scenery part of the Sim. And after touchdown there is a sudden transition after which the plane is only reacting to the phisical shape of the ground scenery. It is this transition, this change that is too violent in my view. MSFS is much more pleasing then FSX but this is one thing that really differs, in FSX there is no transition between flying, flaring and the actual touchdown, it just goes on from one stage to the other with identical handling charactaristics. I'm a MSFS and FSX 'fan boy' When my new sys is complete I hope I will be able to adress this somewhere in the assistance settings. 5 5600X GTX1050TI 2X16 3200 M2 Edited September 3, 2022 by piet06273

[tiger1962]

Thanks for the kind words, Randy and Robert - but Eric deserves them more! I remember using his freeware Airbus panels in FS2002 and FS2004 (they're still in the library here) and his gauges were used in the FeelThere! Airbus series for FS2004 and FSX which I used almost exclusively for about 10 years... along with his superb EasyFMC gauge which can be installed into any FS9/FSX plane.

I have a feeling that something VERY good is going to come from his enquiry above, check out his website here: http://emarciano.free.fr/En/index.htm

[eric_marciano]

Hi Tim,

Thank you for these explanations, very clear. I applied the changes on the C152 and flew to Sedona with real weather. I had 10 kts crosswind.

The effect of the modifications improve the flight behavior but I still have the same problem. OK, 10 kts crosswind is a lot of wind for a light aircraft like the C152, so I can understand it has an impact on the way the aircraft rolls (like in real life), but what I hate is the HUGE difference of behavior before and after touchdown. Before the wheels touch the ground, I control the aircraft very well to maintain on the runway center line, and as soon as the wheel touch the ground, the aircraft suddenly turns right in the direction of the wind. This may be normal because of the crosswind, but in that case why it didn't impact the flight before touch down?

 

I may have the answer. I read on another site that Asobo kept a feature that was existing in FSX: as soon as you go down and reduce the speed, the effect of crosswind is artificially reduced by the sim to become null when you touch down. This may explain why I don't feel the crosswind effect when flying and suddenly feel it when touching down. Anyway, it ruins the realism and I hope it will be fixed soon.

[roypaglia]

Eric this is such a good question because I have exactly the problem you describe. I too have all the assists off, I mostly fly the 320 fbw and, up to now, I thought it was my incompetence. Although I've read Tim's very helpful and competent advice (as always) I'm not going to follow it because I don't trust myself, even though it is very well explained.

Sorry I'm no help at all, but you did ask if anyone's noticed, and I have. At least now I know it's not me"

[tiger1962]

Hi Tim,

Thank you for these explanations, very clear. I applied the changes on the C152 and flew to Sedona with real weather. I had 10 kts crosswind.

The effect of the modifications improve the flight behavior but I still have the same problem. OK, 10 kts crosswind is a lot of wind for a light aircraft like the C152, so I can understand it has an impact on the way the aircraft rolls (like in real life), but what I hate is the HUGE difference of behavior before and after touchdown. Before the wheels touch the ground, I control the aircraft very well to maintain on the runway center line, and as soon as the wheel touch the ground, the aircraft suddenly turns right in the direction of the wind. This may be normal because of the crosswind, but in that case why it didn't impact the flight before touch down?

 

I may have the answer. I read on another site that Asobo kept a feature that was existing in FSX: as soon as you go down and reduce the speed, the effect of crosswind is artificially reduced by the sim to become null when you touch down. This may explain why I don't feel the crosswind effect when flying and suddenly feel it when touching down. Anyway, it ruins the realism and I hope it will be fixed soon.

 

Hi Eric, my apologies for the late reply:

 

I forgot to mention a trick I discovered over a year ago to help with taildraggers ground handling, although it works on all aircraft. In the [CONTACT_POINTS] section of the FLIGHT_MODEL.CFG, you'll see these entries (C172 G1000 in this case):

 

max_speed_full_steering = 10 ; Defines the speed under which the full angle of steering is available (in feet/second).

max_speed_decreasing_steering = 20 ; Defines the speed above which the angle of steering stops decreasing (in feet/second).

min_available_steering_angle_pct = 0.2 ; Defines the percentage of steering which will always be available even above max_speed_decreasing_steering (in percent over 100).

max_speed_full_steering_castering = 20 ; Defines the speed under which the full angle of steering is available for free castering wheels (in feet/second).

max_speed_decreasing_steering_castering = 40 ; Defines the speed above which the angle of steering stops decreasing for free castering wheels (in feet/second).

 

These speeds are too low, even for the C172, and they make the steering over-sensitive to external forces and user inputs at normal ground speeds. I increase them to well over take-off speed range, like this:

 

max_speed_full_steering = 210 ; Defines the speed under which the full angle of steering is available (in feet/second).

max_speed_decreasing_steering = 220 ; Defines the speed above which the angle of steering stops decreasing (in feet/second).

min_available_steering_angle_pct = 0.25 ; Defines the percentage of steering which will always be available even above max_speed_decreasing_steering (in percent over 100).

max_speed_full_steering_castering = 220 ; Defines the speed under which the full angle of steering is available for free castering wheels (in feet/second).

max_speed_decreasing_steering_castering = 240 ; Defines the speed above which the angle of steering stops decreasing for free castering wheels (in feet/second).

 

It's not a complete cure, but it does make crosswinds more manageable.

Edited September 13, 2022 by tiger1962

[pck42]

Hi and thanks for this tweak. I can now land my Caravan properly. However I have looked for other model.cfg and none that I find gives the extensive list of parameters. All are very short perhaps one screen. So how can I do this for Cesena 172 SP or Beechcraft Bonanza. Thank you for your reply

 

Pck42

[tiger1962]

The list of parameters isn't required, each one is commented out by the ; in each line anyway.

These entries will work just fine:

 

max_speed_full_steering = 210

max_speed_decreasing_steering = 220

min_available_steering_angle_pct = 0.25

max_speed_full_steering_castering = 220

max_speed_decreasing_steering_castering = 240

[pck42]

HI! OK I'm more confused now

those parameter are not avail in this C172 Config.[FLTSIM.0]

title = "Cessna Skyhawk G1000 Asobo Munster-EPCW" ; Variation name

model = "MAIN"; model folder

panel = "TPC" ; panel folder

sound = "" ; sound folder

texture = "TPC" ; texture folder

kb_checklists = "Cessna172SP_check" ; Procedures/Checklist sibling file name

kb_reference = "Cessna172SP_ref" ; Reference information sibling file name

description = "TPC1000" ; Variation description.

wip_indicator = 0 ; know if the variation is good to go or still WIP : -1=Disabled, 0=Rough, 1=1st Pass, 2=Finished

ui_manufacturer = "TT:AIRCRAFT.UI_MANUFACTURER" ; e.g. Boeing, Cessna

ui_type = "C172 G1000 TPC Flight School" ; e.g. 747-400, 172

ui_variation = "172 - TPC" ; e.g. World Air, IFR Panel

ui_typerole = "Single Engine Prop" ; e.g. Single Engine Prop, Twin Engine Prop, Rotorcraft, etc

ui_createdby = "Asobo Studio3" ; e.g. Asobo Studio, Microsoft, Wings Creates, etc

ui_thumbnailfile = "" ; app relative path to ThumbNail image file

ui_certified_ceiling = 14000 ; service ceiling / max certified operating altitude (ft)

ui_max_range = 640 ; max distance the aircraft can fly between take-off and landing in (NM)

ui_autonomy = 5 ; max duration the aircraft can fly between take-off and landing in (Hrs)

ui_fuel_burn_rate = 54 ; average fuel consumption per hour (lbs/hr) - Legion: fuel density is ~6.7lbs per US gallon

atc_id = "" ; tail number

atc_id_enable = 1 ; enable tail number

atc_airline = "The Pilot Club" ; airline name

icao_airline = "" ; airline icao code

atc_flight_number = "" ; flight number

atc_heavy = 0 ; heavy?

atc_parking_types = "RAMP" ; "ANY" / "RAMP" / "CARGO" / "MIL_CARGO" / "MIL_COMBAT" / "GATE" / "DOCK"

atc_parking_codes = "" ; Comma separated and may be as small as one character each

atc_id_color = "" ; color for the tail number : i.e. "#ffff00ff"

atc_id_font = "" ; font for the tail number

isAirTraffic = 0 ; Is the plane usable for air traffic

isUserSelectable = 1 ; Is the plane selectable by the user

 

Thanks pck 42

[tiger1962]

That's the aircraft.cfg - in MSFS the various sections from the old FSX-style aircraft.cfg have been separated into their own .cfg files. The one you want is the flight_model.cfg.

[pck42]

HaHa! always thought that Flight_Model.cfg really meant Flight_172.cfg. Thanks

pck42

[davidc2]

I tried this on my Asobo 172, and as I was on final, all of a sudden, my throttle went full power and I was landing at over 120 MPH. Tried the flight a second time, same results

[Josette]

hello! it's true and very unpleasant, on touchdown the plane always tends to turn to the right, or more often to the left, which forces us to compensate excessively on one side or the other, this give messy landings it's maybe a little less blatant on the jets (thought it was because I had everything set to realistic maximum, but anyways seems abnormal behavior )

[Ishrak98]

Hi! I've been flying in MSFS for about 3 months and started noticing the Crosswind Effect recently and it is driving me INSANE. I would just like to ask @tiger1962 if the changes you made in the flight_model.cfg file still applies to this day as of SU13? If so, I will make these changes ASAP. Thanks and let me know!

[tiger1962]

Hi @Ishrak98, yes those flight_model.cfg changes still apply, and I've also added these changes to the [FLIGHT_TUNING] section in the flight_model.cfg:

 

ground_crosswind_effect_zero_speed = 25.2 ; crosswind has no effect below 25.2 feet per second ground speed
ground_crosswind_effect_max_speed = 100.8 ; crosswind only reaches maximum effect above 100.8 feet per second ground speed
ground_high_speed_steeringwheel_static_friction_scalar = 0.5 ; nosewheel or tailwheel steering effectiveness
ground_high_speed_otherwheel_static_friction_scalar = 1.0 ; main gear friction

 

 

[Ishrak98]

Hi! @tiger1962 Thanks for the response! I'm literally testing those numbers right now as I reply. I found the biggest difference is made while on take-off and landing roll is the "ground_crosswind_effect_max_speed" which I'm trying to set near the rotation speed of the aircraft. Also for the previous changes you mentioned in the beginning, do they still apply when using the "Modern" flight model? Because according to the SDK Documentation here https://docs.flightsimulator.com/html/Content_Configuration/SimObjects/Aircraft_SimO/flight_model/aerodynamics.htm, it says it only applies to the Legacy Flight Model. I really didn't know about 2 types before today.

[tiger1962]

12 minutes ago, Ishrak98 said:

Also for the previous changes you mentioned in the beginning, do they still apply when using the "Modern" flight model? Because according to the SDK Documentation here https://docs.flightsimulator.com/html/Content_Configuration/SimObjects/Aircraft_SimO/flight_model/aerodynamics.htm, it says it only applies to the Legacy Flight Model. I really didn't know about 2 types before today.

 

The steering settings are in the [Contact_Points] section, not the [Aerodynamics] section, so yes they apply to the Modern flight model.