2022 cars 'porpoising' at high speed

[Hoffman900]

Using suspension to cure this is like using the American healthcare model. You just want a patch that just suppresses the symptoms and doesn't address the root cause. This is a poor approach unless you want repeat customers.

Race cars are a series of compromises.

If the ability to control rear ride height is the issue, then the suspension is absolutely the solution.

If the issue is vortex shearing causing a resonance, then yes, it isn’t the sole solution, but it may be a combination of suspension and aero.

Same goes for choke flow caused by flow separations.

It’s an entire package.

The suspension is not an ideal solution, it's A solution. If you are forced to use bump stops to keep the car from bottoming out it still doesn't change the car behavior if it's being caused by aero instability. If you limit suspension travel so the car doesn't get too low, then you also limit suspension travel over bumps, you also limit grip at low speed corners. Whereas if you solve the issue from an aero perspective you free the suspension to work in a greater range of conditions. This is why solving the root issue is the way to go in the long run.

I agree 100%, but that’s just a round about way of getting around what I am saying.

I come from the soft spring / big ARB GT world, with progressive stops to smooth the landing. I’m a big believer on getting the mechanical grip component right.

That said, my argument is you can have it both ways, but I suspect the rules have stymied that route by false confidence (ie: banning hydraulic heave springs).

That said, the teams may need to stiffen it up so they can isolate the problem to find out what is happening and where, because the bouncing is absolutely causing havoc to the entire flow field.

[godlameroso]

I can guarantee you in writing, the issue can be solved relatively quickly with a few floor modifications in the bow and the edge wing.







The other solution is to create a more blunted/bulbous bow



Notice the Mercedes with the axe like sharp edged bow, Ferrari and AMR also have their bow like this, but even worse because they have those mini dive planes. As the car oscillates the vortex thrown off by the bow wake waves up and down. So you blunt the bow in order to weaken, or NOT produce a bow vortex.

[shamyakovic]

I can guarantee you in writing, the issue can be solved relatively quickly with a few floor modifications in the bow and the edge wing.

https://files.catbox.moe/u3ezx5.jpg

https://i.imgur.com/qURoEHY.jpeg

https://files.catbox.moe/f5oywz.jpeg

The other solution is to create a more blunted/bulbous bow

https://cdn-1.motorsport.com/images/mgl ... -w13-1.jpg

Notice the Mercedes with the axe like sharp edged bow, Ferrari and AMR also have their bow like this, but even worse because they have those mini dive planes. As the car oscillates the vortex thrown off by the bow wake waves up and down. So you blunt the bow in order to weaken, or NOT produce a bow vortex.

https://imgr1.auto-motor-und-sport.de/S ... 876241.jpg

What do you mean by bow? Is it the tea tray?

[godlameroso]

I can guarantee you in writing, the issue can be solved relatively quickly with a few floor modifications in the bow and the edge wing.

https://files.catbox.moe/u3ezx5.jpg

https://i.imgur.com/qURoEHY.jpeg

https://files.catbox.moe/f5oywz.jpeg

The other solution is to create a more blunted/bulbous bow

https://cdn-1.motorsport.com/images/mgl ... -w13-1.jpg

Notice the Mercedes with the axe like sharp edged bow, Ferrari and AMR also have their bow like this, but even worse because they have those mini dive planes. As the car oscillates the vortex thrown off by the bow wake waves up and down. So you blunt the bow in order to weaken, or NOT produce a bow vortex.

https://imgr1.auto-motor-und-sport.de/S ... 876241.jpg

What do you mean by bow? Is it the tea tray?

Yessir. It's no longer a tray though, it's a bow, and these things are as heavy as boats, so the name is apt.

[Stu]

Using suspension to cure this is like using the American healthcare model. You just want a patch that just suppresses the symptoms and doesn't address the root cause. This is a poor approach unless you want repeat customers.

Race cars are a series of compromises.

If the ability to control rear ride height is the issue, then the suspension is absolutely the solution.

If the issue is vortex shearing causing a resonance, then yes, it isn’t the sole solution, but it may be a combination of suspension and aero.

Same goes for choke flow caused by flow separations.

It’s an entire package.

Tyres & tyre pressures….

[godlameroso]

Using suspension to cure this is like using the American healthcare model. You just want a patch that just suppresses the symptoms and doesn't address the root cause. This is a poor approach unless you want repeat customers.

Race cars are a series of compromises.

If the ability to control rear ride height is the issue, then the suspension is absolutely the solution.

If the issue is vortex shearing causing a resonance, then yes, it isn’t the sole solution, but it may be a combination of suspension and aero.

Same goes for choke flow caused by flow separations.

It’s an entire package.

Tyres & tyre pressures….

You can only go so low, ask Pirelli.

[godlameroso]

This was the hack job Alpine did to cure their 64 Impala in the hood syndrome.

[DiogoBrand]

I can guarantee you in writing, the issue can be solved relatively quickly with a few floor modifications in the bow and the edge wing.

https://files.catbox.moe/u3ezx5.jpg

https://i.imgur.com/qURoEHY.jpeg

https://files.catbox.moe/f5oywz.jpeg

The other solution is to create a more blunted/bulbous bow

https://cdn-1.motorsport.com/images/mgl ... -w13-1.jpg

Notice the Mercedes with the axe like sharp edged bow, Ferrari and AMR also have their bow like this, but even worse because they have those mini dive planes. As the car oscillates the vortex thrown off by the bow wake waves up and down. So you blunt the bow in order to weaken, or NOT produce a bow vortex.

https://imgr1.auto-motor-und-sport.de/S ... 876241.jpg

With teams working so hard to seal the edges of the floor, how do you know the cutouts don't reduce overall downforce?

[godlameroso]

I can guarantee you in writing, the issue can be solved relatively quickly with a few floor modifications in the bow and the edge wing.

https://files.catbox.moe/u3ezx5.jpg

https://i.imgur.com/qURoEHY.jpeg

https://files.catbox.moe/f5oywz.jpeg

The other solution is to create a more blunted/bulbous bow

https://cdn-1.motorsport.com/images/mgl ... -w13-1.jpg

Notice the Mercedes with the axe like sharp edged bow, Ferrari and AMR also have their bow like this, but even worse because they have those mini dive planes. As the car oscillates the vortex thrown off by the bow wake waves up and down. So you blunt the bow in order to weaken, or NOT produce a bow vortex.

https://imgr1.auto-motor-und-sport.de/S ... 876241.jpg

With teams working so hard to seal the edges of the floor, how do you know the cutouts don't reduce overall downforce?

They will if they're poorly designed, but if they're well designed, they'll improve performance everywhere. Because as the first picture shows, the jet from the cutout will push the air in the diffuser out and aid suction upstream. Much like the fan in the fan car was used to extract air from the underfloor of the car, you can use a jet to push out air from the diffuser(where the flow is slowing down). The RB18's nozzle beam wing actually works like a fan to help extract air from the diffuser. It's all about pulling air through the tunnel which will prevent stalling and increase floor performance.

[gcdugas]

I think the tunnels are using gain of width to obtain suction as much as gain of height. IMHO, the tunnels need to be MUCH taller and mostly uniform in width. A shallow but wide tunnel can fill up the entire volume with HP air quickly once the "seal" is broken. A taller tunnel is more apt to retain LP. Yes their will be some variation but the wild amplitude swings we are seeing will be greatly diminished if the tunnels were taller.

[DiogoBrand]

I can guarantee you in writing, the issue can be solved relatively quickly with a few floor modifications in the bow and the edge wing.

https://files.catbox.moe/u3ezx5.jpg

https://i.imgur.com/qURoEHY.jpeg

https://files.catbox.moe/f5oywz.jpeg

The other solution is to create a more blunted/bulbous bow

https://cdn-1.motorsport.com/images/mgl ... -w13-1.jpg

Notice the Mercedes with the axe like sharp edged bow, Ferrari and AMR also have their bow like this, but even worse because they have those mini dive planes. As the car oscillates the vortex thrown off by the bow wake waves up and down. So you blunt the bow in order to weaken, or NOT produce a bow vortex.

https://imgr1.auto-motor-und-sport.de/S ... 876241.jpg

With teams working so hard to seal the edges of the floor, how do you know the cutouts don't reduce overall downforce?

They will if they're poorly designed, but if they're well designed, they'll improve performance everywhere. Because as the first picture shows, the jet from the cutout will push the air in the diffuser out and aid suction upstream. Much like the fan in the fan car was used to extract air from the underfloor of the car, you can use a jet to push out air from the diffuser(where the flow is slowing down). The RB18's nozzle beam wing actually works like a fan to help extract air from the diffuser. It's all about pulling air through the tunnel which will prevent stalling and increase floor performance.

Pulling air from the diffuser is not the same as allowing air into it.

[godlameroso]

With teams working so hard to seal the edges of the floor, how do you know the cutouts don't reduce overall downforce?

They will if they're poorly designed, but if they're well designed, they'll improve performance everywhere. Because as the first picture shows, the jet from the cutout will push the air in the diffuser out and aid suction upstream. Much like the fan in the fan car was used to extract air from the underfloor of the car, you can use a jet to push out air from the diffuser(where the flow is slowing down). The RB18's nozzle beam wing actually works like a fan to help extract air from the diffuser. It's all about pulling air through the tunnel which will prevent stalling and increase floor performance.

Pulling air from the diffuser is not the same as allowing air into it.

If the air you put into it pushes the air out, it's the same as pulling it out. Air doesn't care about pushing or pulling, because those are concepts you use to make sense of the world. Air only follows pressure gradients. There is no such thing as suction if we're using actual technical terms. It's just short hand jargon. Remember that the air from above will always go into the diffuser, there's no avoiding it. That inwash is converted into upwash which is the aim of the rules.

[DiogoBrand]

If the air you put into it pushes the air out, it's the same as pulling it out. Air doesn't care about pushing or pulling, because those are concepts you use to make sense of the world. Air only follows pressure gradients. There is no such thing as suction if we're using actual technical terms. It's just short hand jargon.

If that was correct, then you could generate more downforce by making the front opening of the tunnels as large as possible, but we know that's not the case, you only allow in the tunnels as much air as you can extract at the back.
Push more air in the tunnel than you can pull out and you get something like the Mercedes CLR at Le Mans.

My point is, there's probably no solution other than active suspension that can solve the porpoising issue without a downside somewhere. If the cutouts were such a great solution, teams would've used them before they had an issue in the first place.

[ojir19]

[RedNEO]

Can we rename this thread “2022 cars moving with ‘porpoise’ at high speed”