MSFS flight model

[Rocky 128]

Am I the only one who is 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.

[NZ255 309]

This has been talked about in the dev Q&As as a known issue from FSX and one they want to fix. As I understand it when on the ground winds fade out to nil as your speed decreases. It’s most noticeable in cross winds. 
this could be what you’re noticing.

 

https://www.avsim.com/forums/topic/623427-msfs-my-2-year-review/?do=findComment&comment=4833431

Edited September 2, 2022 by NZ255

[Paul K 1,348]

41 minutes ago, Rocky said:

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

 

No, you're not the only one - it bothers me too. It seems to me that some aircraft are worse than others, so I'm sure it can be addressed.

[Rocky 128]

35 minutes ago, NZ255 said:

This has been talked about in the dev Q&As as a known issue from FSX and one they want to fix. As I understand it when on the ground winds fade out to nil as your speed decreases. It’s most noticeable in cross winds. 
this could be what you’re noticing.

 

https://www.avsim.com/forums/topic/623427-msfs-my-2-year-review/?do=findComment&comment=4833431

No, wind does not fade out when speed decreases, it is the effect of crosswind that decreases with the speed.

I am surprised about what you wrote here because I used to fly FSX before and I never noticed this problem. I saw it in MSFS only.

[Christopher Low 5,359]

1 hour ago, NZ255 said:

This has been talked about in the dev Q&As as a known issue from FSX and one they want to fix. As I understand it when on the ground winds fade out to nil as your speed decreases. It’s most noticeable in cross winds.......

This issue was not present in the version of FSX that I used. It is almost certainly an "MSFS only" problem.

[RLJR 14]

Me too. 

[RLJR 14]

It seems to have a stronger adverse reaction with real weather.

[NZ255 309]

Ah, apologies

[Rocky 128]

1 hour ago, RLJR said:

It seems to have a stronger adverse reaction with real weather.

You're right. I will make some tests with custom weather, including test with no wind at all, I will see if it works better.

[jcomm 5,939]

ASOBO has stated that they intend to rebuild ground physics when possible.

Presently we still have a single contact point and at the same time we have the more realistic effects of the modern flight model and the end result is not the ideal...

Edited September 2, 2022 by jcomm

[sd_flyer 6,049]

3 hours ago, Rocky said:

Am I the only one who is 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.

It's known problem that Asobo already acknowledged and  promised to address. I believe it has to do with friction model while airplane is on the ground. Unfortunately, no sim if prefect and yes it used bother me a lot but not that much lately.Yes it need to be fixed but in meanwhile  it doesn't deter most of us from flying 🙂

[lwt1971 7,420]

@Rocky I posted this on another thread so will copy here... Ground physics/handling is an area Asobo have identified for rework and improvements in the future.. some of which are coming in SU10 and will continue to after that, but we might not see all these improvements ourselves until aircrafts start to take advantage of particular SDK/FDE changes (although in reading Seb's answer below the default Extra 330 will be enhanced to use these improvements in SU10 looks like, and possibly the C172)


From a recent Q&A (underlining my own): https://forums.flightsimulator.com/t/live-dev-q-a-may-25th-2022/521293/2
Chat question – What are some improvements that are coming for ground friction and handling? - Timestamp 3

Seb – Four new parameters are coming in Sim Update 10. Two of them are going to give the possibility to eliminate or at least tune, but we decided to cancel it out on our plane where we tested it. Basically, an old feature that we kept from FSX. FSX was canceling out all crosswind below a certain speed. At 50 knots, you had 100% crosswind, and then it was fading out to 10 knots and then it was 0. The problem is, while you take off or land, the crosswind keeps changing. And it’s very unnatural. So this is something where, in the parameters for the plane you can say at what speeds you want this to happen. So on the Cessna 172, we’re testing this, so we basically canceled the effect completely. So you have a 100% crosswind even if you are parked, or if you go very slow. If there is a lot of wind, it can actually spin your plane around, at first. So that’s one of the new parameters.

Seb – And the other one, two parameters are there to allow you to control how sticky your wheels are when they are rolling fast. So when you are already going pretty fast in the takeoff, the sim was considering the wheels to be pretty much on rails as if there were slick tires from a Formula 1 car. Very sticky. And only the weight…so if you pull on the yoke, your plane gets a bit lighter. And the weight goes down, which reduces friction a little bit. But it’s still static. So it means that as long as you don’t push to the side strong enough, you’re still on rails. And so, there’s two parameters that allow you to make it so that the plane drifts off. The wheels are spinning so if you push to the side, it’s going to drift off a little bit, especially with plane tires that are not anything but racing tires. So we tested that with taildraggers. Taildraggers will always be hard to land and takeoff. But it’s a lot more natural and easy with that. So this is something we implemented on the Extra 330 for Sim Update 10. Also, plane makers have examples of how this works, so they can use it, too. We will deploy on more based on feedback. These four parameters are a first step on improving the ground handling. So more stuff will come afterwards. But Sim Update 10 is going to be these four.

From a previous Q&A (underlining my own): https://forums.flightsimulator.com/t/live-dev-q-a-march-2nd-2022/503504
Forum Community Question - Any update on the revamped ground physics handling/friction? In a past Q&A, we mentioned it had been done. Can you go into more detail and what’s coming up in the future?

Seb - last year in Sim Update 7, there have been a few improvements on ground physics. I think one was related to an assistance. When you turn on assistance of ground rudder – basically it’s the thing when there’s a crosswind and propeller effects and the plane goes all over the place, and you have a hard time using the rudder to just stay straight – that is very tough. And then when you rotate, it changes a little bit because you don’t have the wheels that hold you a little bit in place anymore, and you have to do some rudder work again to stay more coordinated. On ground, you’re basically changing from one system, which is staying straight on the runway to staying coordinated in flight. You have to make the switch. The assistance takeoff rudder does that for you. And previously it was just switched off whenever you rotated. It made this hard transition when you take off. That’s something that has been fixed so that this assistance, instead of switching off instantly when you rotate, it gradually fades out over the first 200-300 feet once you take off. It doesn’t have this brutal thing where the rudder turns off instantly. And there’s other little tweaks and improvements on ground friction that we’ve been improving. Mostly for specific bug fixes on specific planes.

But still, there is a deeper rework we need to do. Basically, it all comes from heavy simplifications that were in the sim 10-15 years ago, which were always assuming that the ground was flat. That’s why you couldn’t have sloped runways or undulated runways. The ground friction model…basically when something’s on the ground and when the brakes are fully engaged, you don’t move at all: The plane sticks to the ground. There’s what one could call infinite friction: There’s no movement at all. This is something we added that didn’t exist at all. And it wasn’t really needed 10 years ago because there were no slopes. When you put a plane on a flat terrain without wind, it’s not going to roll anywhere. But if you put that same system on a slope, it’s going to roll away and not stay there.

There’s also wind. Historically, in the sim, there was a system so that at low speeds, any crosswind was cancelled out. The plane ignores any form of wind, when you’re below, maybe 5-10 feet/second, which is why when you’re stopped on the ground, you go full propeller power and then there’s some propeller effects, so the plane starts going left. And then, all of a sudden, the wind kicks in, and then if you have a strong crosswind, it does this sort of thing which is not realistic. In reality, if I have a plane on the ground, and there’s a strong wind, and I release all brakes, it’s going to start moving: The wind is going to push it. And that currently does not happen. There are changes like that that we want to do. We want to do the ground friction model to make it 100% realistic. Which means that we don’t have to do anything: We don’t have to cancel it out anymore. Everything is going to be realistically simulated from when you stop to when you take off. There’s no such thing as crosswind that comes in over a few knots. I think it’s going to make the rudder a little easier. You’re just fighting one crosswind. It doesn’t change over time unless there’s gusts. Also, it’s going to work better on slopes. This rework is planned for somewhere this year, whenever we have time to go into that. It’s going to be compatible because the parameters are the same. It doesn’t change anything in the way you define or create or make airplanes. It just changes the way all the constraints and forces are sold so that the plane does what it’s supposed to do. All the constraints are the friction, the ground friction, the prop wash, the wind, even the engine, which is slightly shaking the plane. All these things come together. Currently, it’s a little bit better because we worked more in a bug fix development system, where we said, “The plane is sliding on the slope? Let’s fix that.” “The plane is sliding when there’s wind? Let’s fix that” Now we’re in a situation where we need to implement a real system instead of having a block of patches. That’s basically the next step, and that will give us much more realism the precise moment when you rotate.

For example, a wheel is currently simulated as a single point. So, a wheel can resist movement or rolling or sliding when you brake. It does not resist rotation. A wheel can rotate [with a rudder or tiller] without resistance. If you’re in your car and you’re parked, and you turn the steering wheel, if you don’t have power steering, it’s not easy to turn the tire because it’s not a point: It’s a flat surface. It’s a patch on the ground of rubber that you’re moving. The new simulation is going to allow this. This helps with stability when you’re taking off. Currently, the plane is just a tripod of points, and as soon as the nose is up, you feel that it’s already twisting because the wheels are not simulated as patches of rubber. They do not resist rotation enough. These kinds of changes are going to make the moments of takeoff a lot more precise and realistic. Later this year.

Edited September 2, 2022 by lwt1971

[enright 496]

I still think there is a general issue with yaw in the flight model - in the air and on the ground. Crosswinds will push a plane laterally, but they don't tend to pivot the plane and change the direction the nose is pointed in - at least not as drastically as the current flight model does (thankfully - this would be incredibly nauseating if it occurred IRL) . In MSFS the heading of almost any aircraft will swing back and forth by several degrees as you take off and travel through different crosswinds and gusts.

Glad they are adjusting friction on the ground - but hope they also address the root cause of whatever is exaggerating the yaw effect in wind (lack of inertia?). I'm sure most of the third party devs have mentioned this, and Asobo is better than most companies at listening and responding, so I have hope. 

[lwt1971 7,420]

2 hours ago, enright said:

I still think there is a general issue with yaw in the flight model - in the air and on the ground. Crosswinds will push a plane laterally, but they don't tend to pivot the plane and change the direction the nose is pointed in - at least not as drastically as the current flight model does (thankfully - this would be incredibly nauseating if it occurred IRL) . In MSFS the heading of almost any aircraft will swing back and forth by several degrees as you take off and travel through different crosswinds and gusts.

Glad they are adjusting friction on the ground - but hope they also address the root cause of whatever is exaggerating the yaw effect in wind (lack of inertia?). I'm sure most of the third party devs have mentioned this, and Asobo is better than most companies at listening and responding, so I have hope. 

Which particular aircrafts are you seeing this with? I ask because some 3rd party aircrafts have alleviated these issues partially as part of their particular flight model tweaks for their aircraft. Of course the best case would be after Asobo reworks/improves the core ground handling as per their plans.

Edited September 2, 2022 by lwt1971

[sd_flyer 6,049]

2 minutes ago, enright said:

I still think there is a general issue with yaw in the flight model - in the air and on the ground. Crosswinds will push a plane laterally, but they don't tend to pivot the plane and change the direction the nose is pointed in

This is actually correct behavior with cross winds. Nose point into the wind and airplane drift . Take a look