F1 Evaluating ‘Wheel Arches’

[wuzak]

I notice that the Pirelli wet pushes the water out both side of the tyre.

Would it be possible to have it push the water predominately to the outside, reducing the amount that is captured by the car's aerodynamics?

Or would that be too much work for the tyre to do?

[mzso]

F1 is an open wheel series. Cover the wheels up and it becomes another sports car prototype, basically.

I don't have a problem with that, actually, but F1 is currently the pinnacle open wheel formula in the racing stable of the FIA so it's a huge change.

Not basically, not at all. It had covered wheeled cars before.

Open wheel formula, is essentally meaningless. It's just one arbitrary and very nonsensical thing.

As I said, it's currently open wheeled. It's been open wheel since the mid-50s?

Yes, it's arbitrary but so is the requirement for only 4 wheels. Or a requirement for a super licence.

Not good analogies. Open wheels are outright detrimental to everything they're trying to do, and billions are wasted on "managing tire wake", which shouldn't even exist. It's barking mad.
More than four wheels was only ever a peculiarity, which disappeared on its own because the tire supplier wouldn't develop separate tires.
And the super license (as crappy as it is) prevents every fool from jumping in an F1 car and being a danger to everyone in free practice.

[Stu]

They could run slimmer wheels and tyres in the wet as well. Why not? That would generate less spray...

Yes it would… but isn’t the real problem aero-related? With the cars sucking up huge amounts of water and the upwash from the downforce spraying it out the back like a fire hose?

Not sure how skinner tyres (or these wheel guards come to think of it) would create any sort of meaningful reduction

The majority of the spray is water lifted by the tyres - that is then incorporated in to the wake. The cars don't really suck water off the track like a vacuum cleaner (although doubtless some moisture will be lifted that way it will be insignificant compared to the amount of water moved by the tyres. It's why a dry line starts as two tyre tracks, not a full car's width of dry track.

And it's worth remembering that if they reduce the spray then they will increase the time it takes for the track to dry. The guards will just cause most of the water to fall back on to the track behind the tyre.

The best solution to the problem is the development of porous tarmac that can handle the stresses of F1 cars. That benefits all users of the track, of course, which is useful gain for the circuit's owners - many fewer weather related safety issues.

For any guard to function need it needs to increase the size of the water droplets suspended in the air, the tyres create very small droplets (spray) which is easily suspended in the airflow, increase the size of the droplets and they are more likely to fall out of suspension.

[basti313]

Yes it would… but isn’t the real problem aero-related? With the cars sucking up huge amounts of water and the upwash from the downforce spraying it out the back like a fire hose?

Not sure how skinner tyres (or these wheel guards come to think of it) would create any sort of meaningful reduction

The majority of the spray is water lifted by the tyres - that is then incorporated in to the wake. The cars don't really suck water off the track like a vacuum cleaner (although doubtless some moisture will be lifted that way it will be insignificant compared to the amount of water moved by the tyres. It's why a dry line starts as two tyre tracks, not a full car's width of dry track.

And it's worth remembering that if they reduce the spray then they will increase the time it takes for the track to dry. The guards will just cause most of the water to fall back on to the track behind the tyre.

The best solution to the problem is the development of porous tarmac that can handle the stresses of F1 cars. That benefits all users of the track, of course, which is useful gain for the circuit's owners - many fewer weather related safety issues.

For any guard to function need it needs to increase the size of the water droplets suspended in the air, the tyres create very small droplets (spray) which is easily suspended in the airflow, increase the size of the droplets and they are more likely to fall out of suspension.

They just need to mix some oil into the water
I fear you can not change the size of the drops. This is just given by adhesion and the rotation speed of the tire. Two parameters that you can not really change for better.

I would answer mostly on the above:
That the track drys as a small lane is actually bad. It ends up in races like Imola 2021 where no one can overtake until someone tries it and crashes. It would be much better if the track drys not only on the racing line. But you can not change the pick up of the water by the tire, as you want to have as much adhesion as possible combined with a as high as possible displacement. More spray is unfortunately technically linked to a better wet tire.

I think they can just scrap the heavy wet, it does not make sense. Add dry tires to have more FP running in the dry instead.
If you want to make it complicated...give the Inter a bit more displacement and if you want to waste tires for more strategy and safety add a tire between Inter and Slick. Like this they do not have to go for Slicks once the track shows the first sign of a dry line and end up in the gravel.

[mzso]

I would answer mostly on the above:
That the track drys as a small lane is actually bad. It ends up in races like Imola 2021 where no one can overtake until someone tries it and crashes. It would be much better if the track drys not only on the racing line. But you can not change the pick up of the water by the tire, as you want to have as much adhesion as possible combined with a as high as possible displacement. More spray is unfortunately technically linked to a better wet tire.

All the more reason to have the wheels fully covered. Just deposit the water back. And the track will dry on it's own when the rain stops. It will elongate the wet part of the race, but so what?

I wonder if we'll have a race this weekend. It seems rainy again in Spa.

[wuzak]

I would answer mostly on the above:
That the track drys as a small lane is actually bad. It ends up in races like Imola 2021 where no one can overtake until someone tries it and crashes. It would be much better if the track drys not only on the racing line. But you can not change the pick up of the water by the tire, as you want to have as much adhesion as possible combined with a as high as possible displacement. More spray is unfortunately technically linked to a better wet tire.

All the more reason to have the wheels fully covered. Just deposit the water back. And the track will dry on it's own when the rain stops. It will elongate the wet part of the race, but so what?

I wonder if we'll have a race this weekend. It seems rainy again in Spa.

Looks fine for Sunday, only a small amount of rain for Saturday.

[basti313]

I would answer mostly on the above:
That the track drys as a small lane is actually bad. It ends up in races like Imola 2021 where no one can overtake until someone tries it and crashes. It would be much better if the track drys not only on the racing line. But you can not change the pick up of the water by the tire, as you want to have as much adhesion as possible combined with a as high as possible displacement. More spray is unfortunately technically linked to a better wet tire.

All the more reason to have the wheels fully covered. Just deposit the water back. And the track will dry on it's own when the rain stops. It will elongate the wet part of the race, but so what?

I wonder if we'll have a race this weekend. It seems rainy again in Spa.

I totally agree, that would be a good solution if it would work. Elongating the wet part as long as you can race is just fine, maybe even preferable.
BUT...it is only a nice idea. I fear that the massive aero will just suck the air and with it the spray out of small covers. That is what they saw in the test, only an irrelevant part of the spray stays in the wheel arch. If anything they would need full covers like in Formula E...but who wants this?

I think it is just better to scrap the wet tire and be more flexible with race, FP and Q timing.

[Just_a_fan]

I fear you can not change the size of the drops. This is just given by adhesion and the rotation speed of the tire. Two parameters that you can not really change for better.

You can increase droplet size by having the spray impact a surface - it then collects and runs down the surface before dropping off the bottom edge. It's how spray guards work on road vehicles. You get more of a stream of water than a spray of small droplets.

The problem is how to do it on an open wheel racing car. A full guard that wraps around the rear tyre and extends almost to ground level with a rear-projecting bib at the bottom would be great - but how to attach it to the car and still allow tyre changes, etc.

[mzso]

I totally agree, that would be a good solution if it would work. Elongating the wet part as long as you can race is just fine, maybe even preferable.
BUT...it is only a nice idea. I fear that the massive aero will just suck the air and with it the spray out of small covers. That is what they saw in the test, only an irrelevant part of the spray stays in the wheel arch. If anything they would need full covers like in Formula E...but who wants this?

I think it is just better to scrap the wet tire and be more flexible with race, FP and Q timing.

Well, I did say "fully covered"... And everyone who wants to see wet weather racing instead of parking in the pits should want it...
flexible timing won't help on a rainy weekend.

You can increase droplet size by having the spray impact a surface - it then collects and runs down the surface before dropping off the bottom edge. It's how spray guards work on road vehicles. You get more of a stream of water than a spray of small droplets.

The problem is how to do it on an open wheel racing car. A full guard that wraps around the rear tyre and extends almost to ground level with a rear-projecting bib at the bottom would be great - but how to attach it to the car and still allow tyre changes, etc.

Precisely. Someone linked a sportscar in heavy rain before, to illustrate the point. Probably in the infamous belgian gp thread.

I don't think the open-wheel nonsense accomplishes anything but a variety of safety issues like being launched in the air and water spray, and generating noxious drag and turbulence.

But if must stay with it could be mounted on the same as wheel. Only on non-rotating part (is that the "upright" in english?). They could have a mounting point on the other side if they really want to by going through the center of the tire, that's increasing the complexity a tad. They did something like that with the old tire covers, a decade or so ago.

[mzso]

I wonder how many millions of dollars will it take the F1 to discover this revlution:

Where almost none of the water is ended up sprayed around, it neatly flows back on the track.

[Just_a_fan]

I wonder how many millions of dollars will it take the F1 to discover this revlution:
https://i.postimg.cc/xjXXxtxS/k-p.png
Where almost none of the water is ended up sprayed around, it neatly flows back on the track.

Exactly what I've been describing in this thread.

[Farnborough]

I totally agree, that would be a good solution if it would work. Elongating the wet part as long as you can race is just fine, maybe even preferable.
BUT...it is only a nice idea. I fear that the massive aero will just suck the air and with it the spray out of small covers. That is what they saw in the test, only an irrelevant part of the spray stays in the wheel arch. If anything they would need full covers like in Formula E...but who wants this?

I think it is just better to scrap the wet tire and be more flexible with race, FP and Q timing.

Well, I did say "fully covered"... And everyone who wants to see wet weather racing instead of parking in the pits should want it...
flexible timing won't help on a rainy weekend.

You can increase droplet size by having the spray impact a surface - it then collects and runs down the surface before dropping off the bottom edge. It's how spray guards work on road vehicles. You get more of a stream of water than a spray of small droplets.

The problem is how to do it on an open wheel racing car. A full guard that wraps around the rear tyre and extends almost to ground level with a rear-projecting bib at the bottom would be great - but how to attach it to the car and still allow tyre changes, etc.

Precisely. Someone linked a sportscar in heavy rain before, to illustrate the point. Probably in the infamous belgian gp thread.

I don't think the open-wheel nonsense accomplishes anything but a variety of safety issues like being launched in the air and water spray, and generating noxious drag and turbulence.

But if must stay with it could be mounted on the same as wheel. Only on non-rotating part (is that the "upright" in english?). They could have a mounting point on the other side if they really want to by going through the center of the tire, that's increasing the complexity a tad. They did something like that with the old tire covers, a decade or so ago.

Thinking along the same lines as these two parts of posts.

They did use static wheel centre covers a few years back, McL looked particularly neat design with brake vent exit incorporated, that they could use as front mount.

If they were to use above arrangement, fornt mounted centre of wheel, with wrap around to have fixing quick detach to front and rear of existing brake duct, then mount the assembly with the wheels already inside (wet tyres only) to give complete coverage.
Testing something like this, complete coverage with rear lower drip separation, would define just WHAT is possible with complete cover. This could show the potential to then consider the reality of doing anything such as this or indicating if there's still too much spray even without bulk of wheel's water contribution.

In other words, what's the maximum possible scenario with complete cover, define that first and then understand suitability.

Use of pure test mule initially to study, they could even run it between FP at live events like this. May even have decent appearance with black carbon covers looking like tyres too.

[Just_a_fan]

If one is going to go down the route of having "rain covers", the obvious method is to make them a permanent feature of the car, independent of the wheel assembly. As suggested earlier in the thread by mzso(?), the car doesn't have to have open wheels.

A guard that is only fitted when the wets are fitted would need to be part of the wet tyre/wheel construction so that it could be easily added and removed with the conditions. If the teams have to fuss around fitting/removing it, they'll just avoid running the tyre in the first place and we'll be back to being unable to run in wet conditions because a suitable tyre "isn't available / isn't fast enough".

[Farnborough]

I was thinking more of the cancellation of Belgium gp when there was effectively no racing, to speak of.

If there was a effective full wheel cover for wet tyre running, then tyre type could be mandated (as now when starting behind SC) until race control switched the decision to allow from then on a intermediate choice in continuing the race.

Just that full covers would show if there's any possibility in potential to run in full wet by improving visibility. If there's none, or insufficient due to diffuser contribution, then really there's litte point in pursuing it as anything sensible.

Only proof of concept, or the failure to improve is what they need to see initially.

[AMG.Tzan]

If one is going to go down the route of having "rain covers", the obvious method is to make them a permanent feature of the car, independent of the wheel assembly. As suggested earlier in the thread by mzso(?), the car doesn't have to have open wheels.

A guard that is only fitted when the wets are fitted would need to be part of the wet tyre/wheel construction so that it could be easily added and removed with the conditions. If the teams have to fuss around fitting/removing it, they'll just avoid running the tyre in the first place and we'll be back to being unable to run in wet conditions because a suitable tyre "isn't available / isn't fast enough".

Can’t it be part of the rim without rolling around of course?

So that when they fit the wet tires the guard fits together with the rim without having to anything extra on the car during the pit stop…