Why MSFS's turbulence is not over modeled.

[Slides 1,552]

Comparison video of real life vs flight sim. I hope they didn't dial it down just because flight simmers like how things were before.

 

 

[Chock 17,769]

That was an interesting comparison, it certainly proves the new sim has the looks at that airport.

However, that was a flight in fairly smooth air; the time of the flight was early morning (7:15 am). You don't get thermal activity at that time because the sun has a slant range to the ground to create the catalyst for any. 

If we were getting turbulence in the sim at 7:15 am, then something would be seriously wrong. Anyone who flies in the early morning or in the late evening will tell you that the air is quite often incredibly smooth at that time.

So that's part of the nose wasn't bouncing around. But even then he managed to fluff the landing because the sim's low speed pitch control is too twitchy.

As I've said, I don't object to the sim depicting turbulence, and even really bad turbulence, I want it too, but what I do not like at the moment, is the way it does it, by pivoting the aeroplane from its CoG so the nose is bouncing around all over the shop. That's not how turbulence affects an aeroplane; the entire aeroplane is moved by turbulence, so it moves in its entirety up, down sideways etc, with the occasional little roll movement or yaw movement.

[Slides 1,552]

@Chock beyond the way it depicts turbulence in the sim, isn't it fair to say that even in relative stable air, the nose of a light GA aircraft does a fair amount of bobbing? 

[sd_flyer 6,072]

Cool video! With new MSFS you can take any real word video and compare it side by side. But I hope you guys understand that turbulence is weather phenomena and related to lapse rate. So one flight could be in smooth air like in the video above and another day over the same place and very bumpy. Also there are different kinds of turbulence: Clear Air Turbulence, mountain wave, thermals. Turbulence surface friction due to  structures or landscape, or due cumulus clouds  and so on. I

In US we can check weather report called AIRMET TANGO that tells us of known turbulence or possibility of one.. Another way to see if turbulence exists somewhere is to look at PIREP (pilot report).  Pilots like to repot this stuff. There are even jokes about PIREPS like: Cessna XXX report severe turbulence at 5000 ft while B737 flying over the same spot reports light chop 🙂

There are ways to describe turbulence light, moderate, severe and extreme. Also there is turbulence associated with thunderstorm and it goes to convective SIGMET in my experience    this is the most dangerous especially with frontal thunderstorms.

 

 

 

[Chock 17,769]

35 minutes ago, Slides said:

@Chock beyond the way it depicts turbulence in the sim, isn't it fair to say that even in relative stable air, the nose of a light GA aircraft does a fair amount of bobbing? 

Yes the nose will bounce around a bit, but most of what you are seeing when it appears to do that in real life, is the entire aeroplane bouncing around as it traverses through turbulent air. If you think about it logically, the aeroplane (at least in the case of a single engine Cessna) is being pulled through the air by a propeller.

So imagine you are pulling this toy along by its string:

The front of the toy trailer is not going to wander about, pivoting from its middle as it goes over a rough surface; no, it is being pulled from the front, meaning the entire thing will bounce around as it goes along a rough pavement or yard or carpet or whatever. That's how an aeroplane moves in turbulence too. So to depict this kind of thing in a sim, you don't want to emulate it by having the thing pivot from its central point as it keeps going along on a straight vector, you want the entire thing skittering and bouncing over bumps.

What the sim is doing now, is having your aeroplane go straight along a path, whilst it pivots around on its central point. And that's more like this kind of movement:

That's why the nose is all over the place in the sim, and it is not a correct depiction of turbulent movement. It's why even experienced pilots are having trouble with landing in the sim, because it's just not how aeroplanes work and it's gone from being too on rails in preceding sims, to a lazy 'solution' to simulating movement from a central point on the aeroplane model, which is just incorrect.

This is why the landing challenges in the sim are challenging. Not because it's hard to fly an aeroplane, but because you are battling with stupid movement as you try to fly.

 

Edited August 23, 2020 by Chock

[abrams_tank 7,444]

So I'm not a real pilot.  But I was watching Blackbox11's Twitch stream yesterday and he commented on the turbulence.  Blackbox11 is a real life A320 pilot: 

More or less, BlackBox11 felt that the turbulence was not accurate in MSFS.  For the details, you can watch his archived stream from yesterday.  So this is something that Asobo can tweak.

 

[SAS443 1,728]

58 minutes ago, Chock said:

we were getting turbulence in the sim at 7:15 am, then something would be seriously wrong. Anyone who flies in the early morning or in the late evening will tell you that the air is quite often incredibly smooth at that time.

Very valid points!... But does it necssarily have to be wrong if you experience turbulence in early morning?

I flew at 9.am last thursday. I was being tossed about like a ping-pong ball. That's because we also have to deal with mechanical turbulence which in my neck of the woods usually stops at around 3.000ft.

So that begs the question, is it modelled in MSFS?

Edited August 23, 2020 by SAS443

[Chock 17,769]

7 minutes ago, SAS443 said:

It doesn't necssarily have to be wrong?

I flew at 9.am last thursday. I was being tossed about like a ping-pong ball. That's because we also have to deal with mechanical turbulence which in my neck of the woods usually stops at around 3.000ft

True, but mechanical turbulence is caused by flying over undulating (typically mountainous) terrain at fairly low level as you pass through air which is moving up and down over the profile of the ground, where it sometimes develops into wave lift.

Edited August 23, 2020 by Chock

[WestAir 2,524]

Mechanical turbulence is modeled. I took the King Air up for a spin at MTOW off of a 8,500 ft field, killed an engine...

I couldn't climb and flew into a valley trying to figure out how not to crash. Mechanical turbulence from the mountains forced me to perform one of those majestic 1500 ft/min wingtip landings... The kind that wakes up the whole neighborhood. 😂

[Chock 17,769]

What I'd like to see, is the lenticular clouds which normally give away the presence of serious mechanical turbulence; if you can find some good wave lift from that, you'd better make sure you have oxygen on board, because that's FAI Diamond Height Badge material. 🙂

Edited August 23, 2020 by Chock

[Slides 1,552]

@abrams_tank timestamp on that pov?

@Chock I get the point about turbulence affecting the entire airframe and not just each airfoil separately. Even though technically in real life it does affect each airfoil separately. But the net effect isn't as much yo-yoing but dips and jumps. 

Asobo needs to "harmonize" the effects across each airfoil in regular turbulence. They can leave the individual airfoil turbulence effect in more extreme cases like part of the airplane flying into storm cloud. It might break their airfoil air mass simulation though. 

[Slides 1,552]

16 minutes ago, Slides said:

 timestamp on that pov?

About 45 minutes in here: https://www.twitch.tv/videos/718030941

Fascinating insight.

tl:dr: He things the wind that is modeled is too erratic and should be dampened. The aircraft has inertia and should react more slowly to wind changes.

 

Edited August 23, 2020 by Slides

[WestAir 2,524]

4 hours ago, Slides said:

About 45 minutes in here: https://www.twitch.tv/videos/718030941

Fascinating insight.

tl:dr: He things the wind that is modeled is too erratic and should be dampened. The aircraft has inertia and should react more slowly to wind changes.

 

He's all "it's a thing with InErTiA!"
 

 

Edited August 23, 2020 by WestAir

[RudyB24 296]

Here's another comparison video.

 

[tweekz 2,165]

7 hours ago, Chock said:

As I've said, I don't object to the sim depicting turbulence, and even really bad turbulence, I want it too, but what I do not like at the moment, is the way it does it, by pivoting the aeroplane from its CoG so the nose is bouncing around all over the shop. That's not how turbulence affects an aeroplane; the entire aeroplane is moved by turbulence, so it moves in its entirety up, down sideways etc, with the occasional little roll movement or yaw movement.

Very well explained. I hope you've sent them a ticket with that content. 🙂