2022 cars 'porpoising' at high speed

[vorticism]

Need a damper between upright and road surface. Is there such a thing as a tire damper? Might need to reinvent the wheel.

[henry]

I wonder how this behaviour will play out at Eau Rouge/Radillon this year?

It’s likely the cars will be at least as fast on entry as last year, Slower through La Source and a bit heavier but lower drag. So they will hit the compression at around 300kph and the cars will bottom out, no matter how stiff the suspension the tyres will deform enough to ensure this unless they raise ride height considerably.

Unless they can fix the aero so that they don't lose downforce when bottomed out this corner might be undriveable. What chance they revert to the chicane from years gone by?

[Bandit1216]

I have always wondered why not a skid pad titanium skirt-ish thing? A stop that makes sure the car hits the ground before the floor stalls.

Something like that might have even prevented Senna's death.

Let's say the vanes inside the floor entrance would be longer then the bottom of the floor, last 20mm be of titanium. Always keeping a minimum tunnel so the thing won't stall. With an quite substantial penalty should one decide to finish with half of the titanium safety turned to sparks.

[henry]

I have always wondered why not a skid pad titanium skirt-ish thing? A stop that makes sure the car hits the ground before the floor stalls.

Something like that might have even prevented Senna's death.

Let's say the vanes inside the floor entrance would be longer then the bottom of the floor, last 20mm be of titanium. Always keeping a minimum tunnel so the thing won't stall. With an quite substantial penalty should one decide to finish with half of the titanium safety turned to sparks.

I think that’s the purpose of the plank. So the FIA could regulate a thicker plank which would effectively increase the minimum cross section of the venturi. It would also limit the maximum downforce. It might be an admission that they got the ratios between the Venturi elements wrong which would be embarrassing.

[mclaren111]

I wonder how this behaviour will play out at Eau Rouge/Radillon this year?

It’s likely the cars will be at least as fast on entry as last year, Slower through La Source and a bit heavier but lower drag. So they will hit the compression at around 300kph and the cars will bottom out, no matter how stiff the suspension the tyres will deform enough to ensure this unless they raise ride height considerably.

Unless they can fix the aero so that they don't lose downforce when bottomed out this corner might be undriveable.

What chance they revert to the chicane from years gone by?

Madness... Simply take the corner slower...

[Just_a_fan]

I wonder how this behaviour will play out at Eau Rouge/Radillon this year?

It’s likely the cars will be at least as fast on entry as last year, Slower through La Source and a bit heavier but lower drag. So they will hit the compression at around 300kph and the cars will bottom out, no matter how stiff the suspension the tyres will deform enough to ensure this unless they raise ride height considerably.

Unless they can fix the aero so that they don't lose downforce when bottomed out this corner might be undriveable. What chance they revert to the chicane from years gone by?

Have they bottomed out in the last few years? Why should they do so now? And if they do "bottom out", it's the plank that will be in contact with the floor and the tunnels won't be, so air will still flow through them. This is no different to what the cars have been doing ever since the stepped floor rule was implemented.

[henry]

I wonder how this behaviour will play out at Eau Rouge/Radillon this year?

It’s likely the cars will be at least as fast on entry as last year, Slower through La Source and a bit heavier but lower drag. So they will hit the compression at around 300kph and the cars will bottom out, no matter how stiff the suspension the tyres will deform enough to ensure this unless they raise ride height considerably.

Unless they can fix the aero so that they don't lose downforce when bottomed out this corner might be undriveable. What chance they revert to the chicane from years gone by?

Have they bottomed out in the last few years? Why should they do so now? And if they do "bottom out", it's the plank that will be in contact with the floor and the tunnels won't be, so air will still flow through them. This is no different to what the cars have been doing ever since the stepped floor rule was implemented.

I think they do bottom out, hence the yellow patch on the road from worn plank.

The problem appears to be that when the tunnels get too close to the road the size of the tunnel is inadequate for the air flow causing a sudden and large loss of downforce. Last years’ cars made less of their downforce from the floor and the loss was more progressive, not the sudden loss that is triggering porpoising.

[Shrieker]

Unless they can fix the aero so that they don't lose downforce when bottomed out this corner might be undriveable.

Exactly what sprang to mind upon first encounter. There's no way they're going thru there without bottoming out, and from the videos we can tell how sudden the loss of downforce is. As soon as it bottoms out, the car is thrown back up violently.

Another dangerous situation might arise from having to do a sharp manoeuvre on the straights; when trying to avoid something at high speed or jostling for position on the straights. Imagine the car bottoming out the exact moment a huge steering input comes.

Recall Seb @ spa 2010 ?

[vorticism]

I think they do bottom out, hence the yellow patch on the road from worn plank.

The problem appears to be that when the tunnels get too close to the road the size of the tunnel is inadequate for the air flow causing a sudden and large loss of downforce. Last years’ cars made less of their downforce from the floor and the loss was more progressive, not the sudden loss that is triggering porpoising.

Do you know which video or have a link? The plank wear rules should be what prevents teams from running too low. We have yet to see if porpoising/hoping is a problem for all teams. If it isn't it might be down to set-up and aero philosophy, as it implies some teams will have found out how to make a car which is less sensitive at the threshold of minimum ride height.

[101FlyingDutchman]

Surely the choke point in the tunnel will be relatively easy to locate. Either alleviate it by ride height or some sort of “pressure relief valve effect” pushing the air from the stagnation point outwards so you “unchoke” the floor.

[vorticism]

Surely the choke point in the tunnel will be relatively easy to locate. Either alleviate it by ride height or some sort of “pressure relief valve effect” pushing the air from the stagnation point outwards so you “unchoke” the floor.

You can still have relatively low pressure / high velocity during what's called a 'choke,' it's just that the mass flow isn't there any more. So a valve might only be able to entrain air, which wouldn't necessarily help because its the cross sectional size of the tunnel which is the problem.

[henry]

I think they do bottom out, hence the yellow patch on the road from worn plank.

The problem appears to be that when the tunnels get too close to the road the size of the tunnel is inadequate for the air flow causing a sudden and large loss of downforce. Last years’ cars made less of their downforce from the floor and the loss was more progressive, not the sudden loss that is triggering porpoising.

Do you know which video or have a link? The plank wear rules should be what prevents teams from running too low. We have yet to see if porpoising/hoping is a problem for all teams. If it isn't it might be down to set-up and aero philosophy, as it implies some teams will have found out how to make a car which is less sensitive at the threshold of minimum ride height.

I have noted the yellow streak when watching onboards, but I haven’t located one.I think you can see it at around 21 seconds in this [media] [/media].

The plank wear rules are there to discourage low riding, not prevent it. Since they put metal inserts at the wear points it hasn’t been a huge deterrent. This years cars may wear parts of the plank that are not protected, it remains to be seen. It is however the only control the FIA has on ride height.

It may be that some cars are less sensitive but Eau Rouge is extreme. IIRC from commentary a few years ago they pull more than 1G vertically, which is a further tonne of downforce compressing the tyres and suspension reducing ride height.

[vorticism]

I have noted the yellow streak when watching onboards, but I haven’t located one.I think you can see it at around 21 seconds in this https://youtu.be/_86W7YNdvDo .

The plank wear rules are there to discourage low riding, not prevent it. Since they put metal inserts at the wear points it hasn’t been a huge deterrent. This years cars may wear parts of the plank that are not protected, it remains to be seen. It is however the only control the FIA has on ride height.

It may be that some cars are less sensitive but Eau Rouge is extreme. IIRC from commentary a few years ago they pull more than 1G vertically, which is a further tonne of downforce compressing the tyres and suspension reducing ride height.

Thanks. The plank's a bit odd in that it might encourage rather than discourage unsafe set ups. With no plank, you run risk of damaging your floor or wings or chassis. A plank is cheaper to replace than all those parts. Maybe make those titanium blocks out of gold, that might discourage wear. That said, I'll have to assume porpoising isn't a real issue until it is shown to occur commonly in further tests and contests. If it is then you have to wonder what went wrong with the FIA's studies.

[Just_a_fan]

I have noted the yellow streak when watching onboards, but I haven’t located one.I think you can see it at around 21 seconds in this https://youtu.be/_86W7YNdvDo .

The plank wear rules are there to discourage low riding, not prevent it. Since they put metal inserts at the wear points it hasn’t been a huge deterrent. This years cars may wear parts of the plank that are not protected, it remains to be seen. It is however the only control the FIA has on ride height.

It may be that some cars are less sensitive but Eau Rouge is extreme. IIRC from commentary a few years ago they pull more than 1G vertically, which is a further tonne of downforce compressing the tyres and suspension reducing ride height.

Thanks. The plank's a bit odd in that it might encourage rather than discourage unsafe set ups. With no plank, you run risk of damaging your floor or wings or chassis.

The plank (and the rules regarding wear of the plank) was brought in specifically to stop people running on the ground. That, along with the step plane, was intended to prevent the cars losing downforce in a catastrophic way as had happened with the flat floors brought in after the original tunnel cars.

[vorticism]

I wonder if a return of the Renault type TMD would be in order, to quell such oscillations if they turn out to be a problem. Could even be a spec component. That component was originally banned because it was deemed to be a moving part influencing aero, contravening rules originally intended to prevent development of more obvious moveable aero parts such as wings. Yet, now we have spec movable aero in the DRS, and with these ground effect cars the movable parts known as tires and suspension may play a pivotal role in influencing the aerodynamics of the car (i.e. the subject of this thread).

The plank (and the rules regarding wear of the plank) was brought in specifically to stop people running on the ground. That, along with the step plane, was intended to prevent the cars losing downforce in a catastrophic way as had happened with the flat floors brought in after the original tunnel cars.

Were any teams already running a plank before it was prescribed as a spec component? I would assume something like that would have been desireable just to save expensive parts from damage. I guess this gets into a question of whether or not teams can provide their own safety to drivers. There are notable examples in the sport's history where the answer is, "No." We all can recall some of those examples. Yet, for 99% of the time, teams provided a car which was safe for the pilot to operate around tracks for two hours.