7 hours ago, ca_metal said:

That's not what I saw. It clearly turns yellow/red the moment the aircraft lifts. It was green before.

The color is irrelevant because the wake shouldn’t be there at all no matter how weak it is. 

16 minutes ago, ahsmatt7 said:

The color is irrelevant because the wake shouldn’t be there at all no matter how weak it is. 

Of course it is relevant, Seb said the color is related to the intensity of it. And also, TBF he is talking about turbulence, not wake turbulence. And yeah, the engine produces turbulence. And we can see its intensity is higher the moment the airplanes lifts (it turns yellow/red).

Edited October 20, 20241 yr by ca_metal

Below is what ChatGPT has to say about it:

Yes, jet engines can create turbulence behind them, which can be dangerous for smaller aircraft. This turbulence, known as wake turbulence, is caused primarily by two factors:

Jetwash: The fast-moving exhaust gases expelled by a jet engine create a high-velocity stream of turbulent air. This jetwash can be hazardous to smaller planes, especially during takeoff or landing when they are closer to the ground and in proximity to other aircraft.

Wingtip Vortices: All aircraft, not just jets, generate vortices at the tips of their wings as a result of the pressure difference between the upper and lower surfaces of the wing. However, larger aircraft, particularly those with jet engines, produce more intense and longer-lasting vortices. These swirling air currents can remain in the atmosphere for several minutes and pose a threat to smaller planes flying too close behind.

The combination of jetwash and wingtip vortices can disrupt the airflow over smaller aircraft, potentially leading to a loss of control or structural stress. To mitigate this, air traffic control establishes minimum separation distances between aircraft, especially during takeoff and landing. This separation gives the turbulent air time to dissipate, reducing the risk for following planes.

It's gonna be one of this things we'll have to try on release, sit a Cub behind the Beluga and see what happens at full throttle!

4 minutes ago, MarcG said:

It's gonna be one of this things we'll have to try on release, sit a Cub behind the Beluga and see what happens at full throttle!

Yes 😉 But my real first test will be to sit on a cub, let ~3 min after the take off of a big one then take off behind him by taking care of rotating just after the big one's rotation point. 

17 hours ago, ca_metal said:

Of course it is relevant, Seb said the color is related to the intensity of it. And also, TBF he is talking about turbulence, not wake turbulence. And yeah, the engine produces turbulence. And we can see its intensity is higher the moment the airplanes lifts (it turns yellow/red).

It’s not relevant. I’m sorry but wake turbulence isn’t produced until rotation. Therefore, no matter the intensity of the wake turbulence, if they have coded it to happen the second there is power added or the plane is moving is wrong. Wake turbulence shouldn’t be happening until rotation.

jet blast is one thing, wing tip vortices are completely different. My concern when taking off behind a heavy isn’t its jet blast. It’s the wake turbulence and where the heavy rotates. 

I have to assume the variables involved in these air flow dynamics are in data tables that will indeed get fine tuned more over time if an area is off by much.   IOW no reason to insist or even assume it's as perfect as possible at release.

54 minutes ago, ahsmatt7 said:

It’s not relevant. I’m sorry but wake turbulence isn’t produced until rotation. Therefore, no matter the intensity of the wake turbulence, if they have coded it to happen the second there is power added or the plane is moving is wrong. Wake turbulence shouldn’t be happening until rotation.

jet blast is one thing, wing tip vortices are completely different. My concern when taking off behind a heavy isn’t its jet blast. It’s the wake turbulence and where the heavy rotates. 

Of course there is wake turbulence when the aircraft is on the runway, even if probably dampened by the proximity to the ground. Wake turbulence can be created by basically any object through air.

 

And concretely, what we commonly understand by wake turbulence (actually the most dangerous part behind an aircraft, but not the only aerodynamic effectledt behind) is the twin vortex turning turning in the vertical plane. They are generated as soon as the wing produces lift. That is, as soon as the wing starts moving through the air. Of course,  it will be negligible at low speeds,  but significant when close to rotation speed. 

These vortex don't appear instantly when the aircraft rotates.

2 hours ago, ahsmatt7 said:

I’m sorry but wake turbulence isn’t produced until rotation

Well...

1 hour ago, kkbelos said:

They are generated as soon as the wing produces lift. That is, as soon as the wing starts moving through the air.

Exactly. And indeed they are most severe at v1 rotate speed I suppose, but already building up during the take off roll albeit not very strong. Whatever, I assume the development team has done extensive research to get this right and what we see in the video isn't something they just pulled out of a hat.

Edited October 20, 20241 yr by Rimshot

Maybe they're showing jet blast initially in the demonstration.  Because you won't get a vortex until the aircraft comes off the ground.  

This video about 16 sec in.  The wake immediately stops once the aircraft is on the ground.  And the wing is still providing some lift at that initially touchdown speed.

https://youtu.be/ViKYFsN3p24?si=8oNG84myX-enZ3gX

Edited October 20, 20241 yr by ryanbatc

23 minutes ago, Rimshot said:

Well...

Exactly. And indeed they are most severe at v1 rotate speed I suppose, but already building up during the take off roll albeit not very strong. Whatever, I assume the development team has done extensive research to get this right and what we see in the video isn't something they just pulled out of a hat.

 

Can always count on someone who thinks they know better than not only the developers, but also all the consultants they hired. 😮

13 hours ago, Rimshot said:

Below is what ChatGPT has to say about it:

Don't use ChatGPT it isn't accurate, they even warn you at the bottom of the page to double check what it says.

Edited October 20, 20241 yr by Tuskin38

5 minutes ago, Tuskin38 said:

Don't use ChatGPT it isn't accurate

No, no, ChatGPT is my friend 😁😜

4 hours ago, ahsmatt7 said:

It’s not relevant. I’m sorry but wake turbulence isn’t produced until rotation. Therefore, no matter the intensity of the wake turbulence, if they have coded it to happen the second there is power added or the plane is moving is wrong. Wake turbulence shouldn’t be happening until rotation.

jet blast is one thing, wing tip vortices are completely different. My concern when taking off behind a heavy isn’t its jet blast. It’s the wake turbulence and where the heavy rotates. 

He said turbulence, in a more general way. He wasn't being technical. And you can see the graphics were representing the CFD as a whole, not just wake turbulance. Also, again, the color is relevant because you can see the intensity of the forces raise when the plane lifts. Why would they use colors if they weren't relevant? He also said in one of the interviews they want to implement some kind of visual aid so we will be able to spot wake turbulance when it's present. 

The video is just showing the CFD and It was possible to see when the wake turbulance started. Why don't really why are you concerned. Wait for the release and just test it, or wait for the others to test. I'm confident they did a good work based on what I saw.

40 minutes ago, ca_metal said:

He said turbulence, in a more general way. He wasn't being technical. And you can see the graphics were representing the CFD as a whole, not just wake turbulance. Also, again, the color is relevant because you can see the intensity of the forces raise when the plane lifts. Why would they use colors if they weren't relevant? He also said in one of the interviews they want to implement some kind of visual aid so we will be able to spot wake turbulance when it's present. 

The video is just showing the CFD and It was possible to see when the wake turbulance started. Why don't really why are you concerned. Wait for the release and just test it, or wait for the others to test. I'm confident they did a good work based on what I saw.

I appreciate your response. What you say makes sense to me and I agree with your perception and viewpoint.

To be more precise, I say the color isn’t relevant because I don’t think the models wake turbulence correctly. Therefore the colors being present don’t mean much as it’s a moot point. But nevertheless I can see what you mean and have no issues with your take.

vortices should not be happening immediately after an airplane starts to move. There’s absolutely no way enough lift is being created to cause that kind of shape. Secondly, I saw the colors change during rotation but I didn’t see the strength of the vortices change color. I’ll watch it again. 
 

my biggest gripe is that the wake should be constantly increasing as the lift of the wing increases. Contrary to what others say on here, wing tip vortices start when the nose lifts off the ground. Being pedantic and saying “well you’re wrong because they form when a wing has lift” is splitting hairs. During the takeoff roll, wing tip vortices are negligible. They are nowhere near the strength they are when an airplane rotates. The size and shape do not change in the video from what I could see. 
 

Anyways, the pedantic crowd will continue to throw fire at me but I still don’t fully agree with how the simulation is working. However, it’s awesome that’s in the sim to the extent it is.