Ground Effect - Bring It Back

[RicME85]

Minimizing dirty air problem would provide real battles, even if overtakes per GP are a small fraction, but at least we´d see some battles instead of the fastest car with the fastest driver saying it´s imposible to even try because of dirty air

Forget "dirty air" as a problem, because it's one that cannot be solved until someone discovers how to enable an object to pass through the atmosphere without displacing any air whatsoever, a feat that will be worthy of several Nobel Prizes. Absent that, you have to look elsewhere for solutions to facilitate easier overtaking.

DRS works because it makes the trailing car artificially faster than the leading car. If it was applied to both cars, it wouldn't work, because performance differentiation requires something to be different. That underscores the reality that any uniform change made to all cars will ultimately have no effect on overtaking.

So, if we can't address "dirty air," and we can't make wholesale changes to every car, what's left to do?

If the normal line keep level, but you provide a little banking in the outside of the corner, there would be more than one line, the usual and the outer one taking advantage of the little banking, so drivers will have more than one line to choose and overtaking will be easier.

And I don't think you'd have to do that for every corner, just the ones that lead onto, or come after, longer straights. But, I know very little about track design. So, I'm not exactly sure.

The Indian GP circuit had wider sections on some corners to allow different lines through corners.
That worked didn't it?

[bhall II]

I never watched an Indian GP. But if the implication is that track width alone enables multiple driving lines, then I think that's a mistake. A corner needs positive camber to support more than one driving line. Sorta like turn-13 at Shanghai...



An inverted version of the Nordschleife's Carraciola-Karussell, in which the outside line has more positive camber than the inside line, could work...



It would present a challenge, though. I don't think F1 tires particularly like banked corners.

[Andres125sx]

Minimizing dirty air problem would provide real battles, even if overtakes per GP are a small fraction, but at least we´d see some battles instead of the fastest car with the fastest driver saying it´s imposible to even try because of dirty air

Forget "dirty air" as a problem, because it's one that cannot be solved until someone discovers how to enable an object to pass through the atmosphere without displacing any air whatsoever

True, but I think you´ll agree some objects disturb the air more than others when passing through air, right?

Also, some aero concepts are more sensible to dirty air than some others, right?

Then dirty air problem can be maximized or minimized. I agree this is a problem wich will always exist, but you can do it bigger or smaller

DRS works because it makes the trailing car artificially faster than the leading car. If it was applied to both cars, it wouldn't work, because performance differentiation requires something to be different. That underscores the reality that any uniform change made to all cars will ultimately have no effect on overtaking.

Disagree bhall, not about perfomance differentiations but about relationship of dirty air here.

Dirty air does not affect perfomance differentiations, but makes it more or less relevant. With a lot of dirty air you need a huge perfomance difference to overtake because the trailing car need to start the straight at some distance, so to overtake the perfomance difference need to be huge

OTOH if there´s no dirty air or very little, then the trailing car can start the straight much closer to the car in front, so perfomance difference only need to be a bit noticeable to overtake.

Overtaking wise, dirty air and perfomance differentiation are directly proportional. Little dirty air and overtaking will be posible with small perfomance differences. A lot of dity air, and overtaking will be posible only with huge perfomance differentiations.


So if you keep same pefomance differentiations beteween cars, but minimize dirty air problem, overtaking will be easier

If the normal line keep level, but you provide a little banking in the outside of the corner, there would be more than one line, the usual and the outer one taking advantage of the little banking, so drivers will have more than one line to choose and overtaking will be easier.

And I don't think you'd have to do that for every corner, just the ones that lead onto, or come after, longer straights. But, I know very little about track design. So, I'm not exactly sure.

Same here, I think to allow different lines the inner line should be flat or that will continue being the fastest one, but not sure if it´s posible to keep the inner part flat and the outer part banked

[rjsa]

The whole car is already in ground effect, and moving to venturi tunnels would just change the nature of the problem.

I can´t disagree with you obviously, but after reading this it looks like efficient aerodynamics with low drag (wich causes few turbulence) would be the same as high drag solutions, no difference, when it´s not.

Again, the cars are already in ground effect. Think of the front wing as a diffuser, and it makes more sense...

http://i.imgur.com/nkV500Y.jpg

So, given this...

The front wing idea didn’t work from an overtaking perspective; it wasn’t very obvious because Pirelli tyre degradation and DRS contributed to a significant increase in overtaking anyway post 2011.

...venturi tunnels would just make the problem look different.

Personally, I'd like to see tracks somehow modified to accommodate a second viable racing line. That would make a bigger difference than anything else, because the solution would last a lot longer than modifying cars that continuously evolve toward greater sensitivity as a matter of course.

While there might be a GE component to the front wing's downforce it's just that, a component. You are entirely disregarding the top side of the wing. And the fact that the multi element wing kills the speed gradient by feeding fresh air downstream from the choke point.

So no, ventruries wouldn't make the same problem look different. They are not wings.

[mertol]

Can't they just get rid of the front wing and allow a little bigger diffusers with a little more rearwards weight bias if they want to keep the same pace as now. There have been cars without front wings in f1 before:

[Ciro Pabón]

An inverted version of the Nordschleife's Carraciola-Karussell, in which the outside line has more positive camber than the inside line, could work...

http://i.imgur.com/HEoa2G3.jpg

It would present a challenge, though. I don't think F1 tires particularly like banked corners.

Hi, bhall!

Variable sideslope (camber) implies that the space beyond the curve (runoff area) has to be increased.

You know, the problem here is that curves like Nordschliefe carrousel survive today only because they are grandfathered.

That´s the reason why the Autódromo Hermanos Rodríguez will not use the famous Peraltada (sigh) is because there is no way to move the baseball stadium that lies beyond it.

Loss of Peraltada corner unavoidable says Tilke

Current designer could not find a way to create the extra runoff needed without moving the stadium at the inner part of the curve


As you mention, the traditionally the solution has always been a parabolic shape (or, as you say, an ¨inverted¨ profile of the Carousel).

Brooklands variable sideslope, circa


Building a high sideslope curve is not easy, if digression is allowed.

That´s a picture a friend sent me (by Francisco Gómez): it´s not easy to hold in place a paver and a compactor...


As you can see, you introduce problems in asphalt compaction, as the equipment is leaning on one side, thus exerting variable force on the pavement.

Now, how great should be the increase in grip to be able to overtake?

Allow me to digress a bit again. As you know, I prefer numbers over opinions, so, let´s play with numbers a bit.

The problem here is that, with a slight increase in grip provided through banking, you need a long curve if you wish for the overtaker to catch the overtaken before the exit of the curve, where the overtaken can block.

For example, I take the Renault curve, which is the longest curve at Catalunya track (the one in red thick lines, lower left:

The numbers for radius and length I have deduced, so they can have errors


Length of the curve: 198 m
Radius: 111 m
Deflection (the angle between entrance and exit straights): 102 degrees
Maximum speed: 195 kmh (from FIA site)

The centripetal acceleration I arrive to is 2.7 Gs, or, what is the same, the lateral friction coefficient, plus any sideslope already in place, is 2.7

The time it takes to travel through the curve is a mere 3.7 seconds.

Now, if you increase the lateral grip to 2.85 Gs (by increasing banking 15%) you can get an increase in speed to 200 kmh.

This means that by increasing grip 15% you gain only 5 km/h. In the 3.7 seconds it takes to move through the curve you gain only 5 meters.

Let's say, for the purpose of this post, that an advantage of 15 meters would do the trick and allow you to overtake. Yes, I know the cars are shorter, but they are not bumper to bumper and you need a gap to take again the race line.

To gain 15 meters through the curve you need to go at 210 kmh while the overtaken goes at the same 195 kmh we assumed initially as the "regular speed" for the curve.

This means that, at the Renault curve in Catalunya, the overtaker has to produce 3.2 Gs laterally, while the overtaken uses only 2.7 Gs. This will give you a difference in time to travel the curve of a mere 0.3 seconds. The difference in grip is 3.2 - 2.7 = 0.5 Gs.

Conclussion: you need 0.5 Gs of advantage in grip if you want to overtake at Renault. That can only be achieved by a VERY high banking of 30 degrees.

For regular cars, without ground effect, well, any increase in sideslope gives you an advantage that might be enough to overtake, because you are using around 1.2 G´s: that´s why, I think, people still enjoy Carousel on weekends with their street cars.

For cars that depend on aerodynamic forces for grip, sideslope is not that important, because gaining 0.2 G´s when your car is developing 2 or 3 G´s is very little: in the time it takes to traverse the curve you do not get enough advantage.

So, what can we do? Well, we can lengthen the curve, can´t we?

If the Renault curve were longer, what would happened? I'll add the length of the transition that exists after the circular part of Renault (the curve with the thick orange lines in the previous image). It measures 193 meters more, for a total length of 393 m.

Now the overtaken uses 7.2 seconds to travel the curve. I'll spare you the numbers, but the overtaker now only needs a grip of 2.9 Gs!

As the overtaken car is using a grip of 2.7, you need a banking differential of only 20%. This is how it would look in real life a first drawing showing a section of the curve:



Notice that a car running between the two I ¨drawn¨ in the previous image would have problems at Carousel if using ground effect skirts, because of the discontinuity in the slope. That´s why I drew a transversal profile with a circular shape.

I think that explains a little the difficulties you have overtaking in cars with aerodynamic grip.

If Indycars still use high sideslopes is for them not to brake as much as F1. More than allowing to overtake, sideslope allows for a constant velocity in a track with short straights and high deflections (180 degrees curves).

Hope this helps to understand F1 a bit.

[mertol]

The point is not to overtake before the end of the curve but to not lose speed behind the other car - so it is enough just to have another equally fast line through the corner. You extreme banking would just make everyone drive on the outside where the high banking is.

[Ciro Pabón]

The point is not to overtake before the end of the curve but to not lose speed behind the other car - so it is enough just to have another equally fast line through the corner. You extreme banking would just make everyone drive on the outside where the high banking is.

Hi, mertol, nice to meet you. I´ve always looked for what you suggest.

However, it´s not ¨my¨ extreme banking. It´s Brookland´s and NASCAR.

Brooklands was built in 1909, and, nonwithstanding opinions from other members that could tell you I was born in the Jurassic, no, I wasn´t born then.

Besides, I´m explaining why differential banking is impractical for ground effect cars, in case I wasn´t clear.

It´s used in NASCAR because the ground effect in those cars is, I think, less than half of F1 cars.

Finally, I imagine you´re suggesting the banking differential can be made subtle and the difference in speed could be balanced so the time it takes for the inner line is the same to the time it takes for the outer line, so the idea could have its merits.

I´ve tried in TC2000 (at Córdoba, Argentina) and in karts (at Juan Pablo Montoya Kart Track, in Bogotá, Colombia), with varying results, not as good as I expected.

At Córdoba, drivers rebelled. At JPM Track, nobody noticed. I guess it happened because the experience of the drivers was very different.

Unfortunately, in case I haven´t been clear enough about the physical restrictions, marbles are always at the outer line and, thus, rubber is in the inner line.

In the end, I conclude, after many years, that, at least for me, is very difficult to create different lines on the same curve.

Not even in NASCAR there are same time racing lines: you don´t observe cars at extreme bankings using the outer line.

Believe me, I´ve tried at every circuit I´ve designed, I haven´t been able to achieve what you want, that is, ¨equally fast lines through the corner¨.

If you have any idea, I´m all ears: I´m currently designing a race track in Tuluá (Colombia) so we could run it through the simulator and we have a very good one, natively developed.

The only thing that got me thinking was this amazing way to clean streets they invented in South Korea. I loved the minute I saw it:

IF you could bury this things in the asphalt and IF you could use compressed air, well, perhaps we could get rid of marbles

[Andres125sx]

Hi Ciro, nice to read you

Unfortunately, I disagree with you again

IMO your example starts from a point wich is not correct, or is too exagerated

The problem here is that, with a slight increase in grip provided through banking, you need a long curve if you wish for the overtaker to catch the overtaken before the exit of the curve, where the overtaken can block.

The overtaker does not need to overtake in the middle of the curve, if the multiple lines allow him to avoid the dirty air, that´s enough to start the straight close to the car in front. Slipstream and big balls at the braking point will do the rest, contrary to what happens today when they need to be so far that not even the biggest balls can make it posible

So the banking does not need to be that high, the overtaker actually doesn´t need to gain any space, well he need to gain the meters he´s doing in excess because of going at the outer line, but if he can stay as close to the car in front at the exit of the corner as he was before the corner, then it will be enough

So without doing any numbers, just taking your calculations, 15% banking will be enough as I don´t think the outer line will be more than 5m longer than the inner one

[Andres125sx]

Besides, I´m explaining why differential banking is impractical for ground effect cars, in case I wasn´t clear.

Assuming 30% banking, maybe with 15% banking, done with a parabolic shape (no angles) it may be posible?


Marbles are at the outside because no car pass there, if you find the perfect angle to make both lines equally fast, then there will be cars on both lines and they´ll clean the track from marbles.


Maybe you could see some MX races to get some inspiration, this technic is used in MX for decades. IMO a key factor is doing the outer and inner lines as close as posible in the chord of the corner, and the banking must be constant from the beginning of the corner (when the traditional line move to the inner part) to the exit of the corner (when the traditional line join the outer line). At least that was my personal requirement when racing in MX to get an outer line, otherwise I always went to the inner one. But even when I usually got the inner line on a specific corner, when trying to pass someone the outer line was a great option in the same corner, specially to avoid dust from the bike in front. Applied to F1, even if you can´t use it to overtake, you can use it to keep close to the car in front waiting for a mistake because you´re not into dirty air

edit: obviously this is valid only for some corners, there will always be corners where the inner line will always be better.

[toraabe]

I have said it before and I do it again.
The rear diffusor in the current format is far to steep and short. Get rid of it.
Ban any kind of diffusor rear of the diff.
Instead use the floor to generate most of the downforce ..
Like this http://www.f1fanatic.co.uk/wp-content/u ... -re30b.jpg

With skirts would have been great fun . Fast quick supersoft tyres, and so fast in the corners than the drivers really has to cope with it.
1200hp engine race trim...

Minimizing dirty air problem would provide real battles, even if overtakes per GP are a small fraction, but at least we´d see some battles instead of the fastest car with the fastest driver saying it´s imposible to even try because of dirty air

Forget "dirty air" as a problem, because it's one that cannot be solved until someone discovers how to enable an object to pass through the atmosphere without displacing any air whatsoever, a feat that will be worthy of several Nobel Prizes. Absent that, you have to look elsewhere for solutions to facilitate easier overtaking.

DRS works because it makes the trailing car artificially faster than the leading car. If it was applied to both cars, it wouldn't work, because performance differentiation requires something to be different. That underscores the reality that any uniform change made to all cars will ultimately have no effect on overtaking.

So, if we can't address "dirty air," and we can't make wholesale changes to every car, what's left to do?

If the normal line keep level, but you provide a little banking in the outside of the corner, there would be more than one line, the usual and the outer one taking advantage of the little banking, so drivers will have more than one line to choose and overtaking will be easier.

And I don't think you'd have to do that for every corner, just the ones that lead onto, or come after, longer straights. But, I know very little about track design. So, I'm not exactly sure.

The Indian GP circuit had wider sections on some corners to allow different lines through corners.
That worked didn't it?

[bhall II]

True, but I think you´ll agree some objects disturb the air more than others when passing through air, right?

Also, some aero concepts are more sensible to dirty air than some others, right?

Then dirty air problem can be maximized or minimized. I agree this is a problem wich will always exist, but you can do it bigger or smaller

While there might be a GE component to the front wing's downforce it's just that, a component. You are entirely disregarding the top side of the wing. And the fact that the multi element wing kills the speed gradient by feeding fresh air downstream from the choke point.

So no, ventruries wouldn't make the same problem look different. They are not wings.

What I've said is that there's no solution that will completely eliminate the influence of "dirty air" because there is no way to eliminate the reality that a car will displace air as it passes through the atmosphere. That means a trailing car will always have less air flow passing over, under, around, and through its aerodynamic devices, whatever they might be.

Given two ground effect cars...



The trailing car is going to see a lot of this...


Yes, I'm well aware that this is not an exact representation.

But, the upwash from the leading car's rear wing is going to pull it up. So, it's really going to look a lot like what we have now...



And you've just relocated the problem, because, between two cars with venturi tunnels, the one operating at higher efficiency will always be faster through a corner than the one operating at reduced efficiency.

The glory days of overtaking were wholly enabled by cars with a variety of engines running with different fuel loads. That supplied the required performance differentiation, and everything else was coincidental. At least, that's the way I see it.

Hi, bhall!

Variable sideslope (camber) implies that the space beyond the curve (runoff area) has to be increased...

I was hoping you'd weigh in. Now I've moved from knowing very little about track design to knowing little about track design.

Thanks!

[rjsa]

True, but I think you´ll agree some objects disturb the air more than others when passing through air, right?

Also, some aero concepts are more sensible to dirty air than some others, right?

Then dirty air problem can be maximized or minimized. I agree this is a problem wich will always exist, but you can do it bigger or smaller

While there might be a GE component to the front wing's downforce it's just that, a component. You are entirely disregarding the top side of the wing. And the fact that the multi element wing kills the speed gradient by feeding fresh air downstream from the choke point.

So no, ventruries wouldn't make the same problem look different. They are not wings.

What I've said is that there's no solution that will completely eliminate the influence of "dirty air" because there is no way to eliminate the reality that a car will displace air as it passes through the atmosphere. That means a trailing car will always have less air flow passing over, under, around, and through its aerodynamic devices, whatever they might be.
...

Previous experience shows that GE cars do get air enough to chase one another:

[bhall II]

Looks a lot like a less-refined version of this...

[rjsa]

Looks a lot like a less-refined version of this...

https://www.youtube.com/watch?v=e9tsdFbA8UM

Nah, that's a case of 'can't get close enough to pass', exactly what needs fixing.