Cleaning the flow behind an F1 car?

[Ogami musashi]

I think the FIA should enforce a downforce limit, not by say 15,000N max downforce as teams will try to have 15,000N of downforce at low speeds, but limit it by lift coefficent. This would ensure teams worked towards reducing drag which over time would improve the wake of the car.
All the other ideas, except for spec aero (if that happened i would stop watching f1) would increase overtaking for the first few races, but it would become increasingly more difficult to overtake as teams clawed back downforce. A downforce limit would ensure that the wake should continually improve as drag reduces, so overtaking continues to become easier

Your idea seems attractive but there's some problems that would make it not effective for overtaking.

In the case drag reduction would effectively lead to laminar flow behind the car (my second point is already half bring) you would then have a big problem: Slipstream would decrease, thus the following car would less and less benefit from reduced drag.

The second thing is that drag reduction on a car doesn't mean laminar flow past it.

A diffuser is a tool for reducing drag yet it creates turbulence.

The reasons are twofold:

-you can't have a pure laminar flow behind a car (or a plane) for the car even being airfoil shaped would still force the flows (separated in upper or lower parts) to turn at its most aft point to rejoin again.

This will lead to separation all the way out.
This is especially true since what is important for the following car is the turbulence at ground level and that very ground + the wheels of the following car will lead to turbulence anyway.

-The car not being symmetrical you'll have pressure gradient aft of car, and those pressure gradient will develop into wakes.



It is true that not paying attention to drag can be a problem, but you'd be surprised to know that F1 cars except for their rear wings, are very low drag as far as their bodies are concerned and that most of the wake problems come not from drag wake but from downforce creation related flows.

[WhiteBlue]

On your 4th point whiteblue. How would you measure the downforce? To make sure that at no point the car goes over the 1 metric ton (just for example). The only reason i ask is that if this was the rule then the teams would run at exactly 1 metric ton (all agreed?), so if some external fact eg air pressure effected this and took it over the limit, we would after the race see people being disqualified for going over (which nobody wants).

I agree with the Idea, its just how you do it thats the problem.

All you need is a sensor to each wheel and a bit of programming to the ECU. Obviously you would take out inertial forces with another sub routine of the evaluation program which would be done via the existing accelerometers. You then monitor the downforce and you have a public penalty table for transgressions. Race control or live timing can even tell the viewers automatically with the timing which penalty is applicable to each car at any time during the race should the team mess up. You can have adjustable wings as FiA proposed to fine tune downforce in order to stay away from the limit.

If you don't like that kind of adjustable wing or automatic time penalty you can have an integrator which gives you two limits which could be used like a yellow and red card in soccer. Yellow is a warning that you are in serious trouble and have to pit to reset your downforce. If you exceed red you get a meat ball with your number.

[Just_a_fan]

On your 4th point whiteblue. How would you measure the downforce? To make sure that at no point the car goes over the 1 metric ton (just for example). The only reason i ask is that if this was the rule then the teams would run at exactly 1 metric ton (all agreed?), so if some external fact eg air pressure effected this and took it over the limit, we would after the race see people being disqualified for going over (which nobody wants).

I agree with the Idea, its just how you do it thats the problem.

All you need is a sensor to each wheel and a bit of programming to the ECU. Obviously you would take out inertial forces with another sub routine of the evaluation program which would be done via the existing accelerometers. You then monitor the downforce and you have a public penalty table for transgressions. Race control or live timing can even tell the viewers automatically with the timing which penalty is applicable to each car at any time during the race should the team mess up. You can have adjustable wings as FiA proposed to fine tune downforce in order to stay away from the limit.

If you don't like that kind of adjustable wing or automatic time penalty you can have an integrator which gives you two limits which could be used like a yellow and red card in soccer. Yellow is a warning that you are in serious trouble and have to pit to reset your downforce. If you exceed red you get a meat ball with your number.

If you're using the standard ECU, you could just have the system reduce the rev limit by e.g. 2k revs for the period that the downforce is excessive. Perhaps give a warning light on the dash and then say 2 seconds later reduce the revs. Wouldn't want the rev kill to end up causing a crash!

Alternatively, use GPS to ensure that the rev limit is imposed on the next straight. The car might then be quicker in the corners but would be easy meat on the following straight.

It would need to be a very robust system for ensuring d/f levels were exceeded though. Any penalty imposed because of a faulty sensor reading would cause uproar amongst the relevant fanboys for that car...

[WhiteBlue]

An outspoken comment from Tony Purnell

The root cause is that the cars are not good racing cars. The formula is badly designed, [and] the will to please the public really isn't there. The sad thing is that there are solutions, but no-one is really brave enough or forceful enough or probably convinced enough that they will do anything about it. When they look at the politics of change they all just groan and say, 'Well, I don't want to fight that battle'.

[Gary]

On your 4th point whiteblue. How would you measure the downforce? To make sure that at no point the car goes over the 1 metric ton (just for example). The only reason i ask is that if this was the rule then the teams would run at exactly 1 metric ton (all agreed?), so if some external fact eg air pressure effected this and took it over the limit, we would after the race see people being disqualified for going over (which nobody wants).

I agree with the Idea, its just how you do it thats the problem.

All you need is a sensor to each wheel and a bit of programming to the ECU. Obviously you would take out inertial forces with another sub routine of the evaluation program which would be done via the existing accelerometers. You then monitor the downforce and you have a public penalty table for transgressions. Race control or live timing can even tell the viewers automatically with the timing which penalty is applicable to each car at any time during the race should the team mess up. You can have adjustable wings as FiA proposed to fine tune downforce in order to stay away from the limit.

If you don't like that kind of adjustable wing or automatic time penalty you can have an integrator which gives you two limits which could be used like a yellow and red card in soccer. Yellow is a warning that you are in serious trouble and have to pit to reset your downforce. If you exceed red you get a meat ball with your number.

I like this train of thought and (as a complete non-physicist) it's precisely something I've been pondering recently.

- I see the sensors streaming to race control and the car's pit all the time.
- The maximum allowable downforce would only apply at a very high speed (300km/h?) since the object of the exercise is to significantly reduce the disruptive effect of turbulence and it follows that at all lower speeds the area of turbulence would be commensurately smaller and less intense.
- The max downforce limit would not apply at all during braking since the time during which the accelerometers would report 'excessive' downforce in this situation would be momentary and then only when braking from 300km/h and above.
- I see the maximum allowable downforce being very significantly lower than at present. If, say, 1500kg is imposed on the car at 300km/h, my model would see that being reduced to 750kg. Still 150kg or so above the static weight of the car. (I should add that I don't know how much downforce the current crop of cars develop at 300km/h so I do stand to be corrected here.)
- This approach cuts through all the prescriptive suggestions as exemplified in the CDG wing proposal and from the numerous pundits! The trouble with prescriptive rules is that they challenge creative engineers to think of ways round the rules and the spirit, Eg Brawn et al last year.
- Instead, it proposes a single measure which will be totally transparent in real time.
- The teams can have all the wings (read advertising space), winglets and underbody magic they like... so long as they don't exceed the downforce limit.
- Thus this means drag will be reduced.
- Straight line speed will be increased.
- Braking distances will be increased. (Less downforce).
- Cornering speeds will be reduced.
- Turbulence behind a car will be significantly decreased.
- The cars will be harder to get the best out of.
- Thus we will see a greater emphasis on driver skill.
- Overtaking will become more possible.

I will concede that there is a large element of artificiality in this major proposal but we have many items of artificiality right now with more being proposed. We're not about to go back to Formula Libre but my fear is that if the tinkering continues we'll wake up one day and find that F1 has become a spec formula a la NASCAR.

This proposal allows the possibility of all sorts of innovation. But it still puts an undodgeable clamp on notching up that enemy of interesting racing, monster downforce and its hand maiden, turbulence that would lift a freight train off its tracks.

I shall now go and hide in the bunker!

[kilcoo316]

To have a constructive discussion it is necessary for both parties to know what they are talking about. You, unfortunately, appear to be pronouncing on an article you have failed to comprehend or, more likely, failed to read. Here are some of the bits you have missed:

My bad - I thought you were asking for implementation of the CDG wing.



You are asking for the recommendations of the OWG to be implemented - they were - but then the double diffuser farce happened. Instead of banning it... for some reason they ruled it legal.

[BreezyRacer]

what i thought is that underbody tunnels instead of an diffuser have alot cleaner airflow exiting, what if you take 2 tunnels at the car centerline? that would develop possibilities and also makes the underbody less 'important'.

What I would like to see tried is a two tunnel inlet, drawing in airflow from the front of sidepods much like they do now BUT with single center exit with a max width of maybe 2500 to 3000 mm and no real height limits, and do away with the rear wings or go single element rear wings at a tall fixed height, mainly for appearance. I would also mandate more rear overhang and maybe even a spec profile behind rear tires so the tire turbulence can be controlled better.

What this would do is to provide a wide profile for inlet air and a narrow profile for diffused airflow. I admit is something of a packaging nightmare for trannies and diffs, but that is then something for designers to compromise thru and solve. They all make their tranny boxes now anyways.

The anticipated result would allow cars to follow each other in staggered formation, conceivably without much loss of downforce. Of course all this would have to be worked out via CFD and see if the results would warrant the research, but it should work to minimize wake and provide a wider range of aero stability while running close together.

[kilcoo316]

What I would like to see tried is a two tunnel inlet, drawing in airflow from the front of sidepods much like they do now BUT with single center exit with a max width of maybe 2500 to 3000 mm and no real height limits, and do away with the rear wings or go single element rear wings at a tall fixed height, mainly for appearance. I would also mandate more rear overhang and maybe even a spec profile behind rear tires so the tire turbulence can be controlled better.

What this would do is to provide a wide profile for inlet air and a narrow profile for diffused airflow. I admit is something of a packaging nightmare for trannies and diffs, but that is then something for designers to compromise thru and solve. They all make their tranny boxes now anyways.

The anticipated result would allow cars to follow each other in staggered formation, conceivably without much loss of downforce. Of course all this would have to be worked out via CFD and see if the results would warrant the research, but it should work to minimize wake and provide a wider range of aero stability while running close together.

Hmmm....

What about extending the floor forward? The aero-centre from the floor is behind the c.g. point at the minute. If the floor was extended forward, then the front/rear wings could be dramatically limited in scope (as you've proposed with the rear wing), and used as minor trim devices only.


We know the floor is relatively insensitive to upstream turbulence (c.f. the wings), but we know the diffuser screws up the wake for the car behind.

[BreezyRacer]

Yes, extending the floor forward could be an option, kind of like extending it to the current splitter area. While it wouldn't produce much more downforce, it would allow the pressure center to be moved more forward in the chassis, were that needed.

In order to have most downforce come from the underbody you have to have an exit. My thinking is that limiting the exit area to the center of the chassis you are producing a narrower wake, especially when combined with some defined bodywork to control the wake and turbulence coming off the rear tires.

BTW, When using tunnels you have a lot more flexibility when it comes to controlling where the pressure center is located in the chassis.

[Just_a_fan]

What I would like to see tried is a two tunnel inlet, drawing in airflow from the front of sidepods much like they do now BUT with single center exit with a max width of maybe 2500 to 3000 mm and no real height limits, and do away with the rear wings or go single element rear wings at a tall fixed height, mainly for appearance. I would also mandate more rear overhang and maybe even a spec profile behind rear tires so the tire turbulence can be controlled better.

What this would do is to provide a wide profile for inlet air and a narrow profile for diffused airflow. I admit is something of a packaging nightmare for trannies and diffs, but that is then something for designers to compromise thru and solve. They all make their tranny boxes now anyways.

The anticipated result would allow cars to follow each other in staggered formation, conceivably without much loss of downforce. Of course all this would have to be worked out via CFD and see if the results would warrant the research, but it should work to minimize wake and provide a wider range of aero stability while running close together.

Hmmm....

What about extending the floor forward? The aero-centre from the floor is behind the c.g. point at the minute. If the floor was extended forward, then the front/rear wings could be dramatically limited in scope (as you've proposed with the rear wing), and used as minor trim devices only.


We know the floor is relatively insensitive to upstream turbulence (c.f. the wings), but we know the diffuser screws up the wake for the car behind.

This is sort of what I was proposing previously but was poo-poo'd on

In effect you're looking at a version of the Lotus 79 without the skirts or the big rear wing.

Or you could move the floor's centre of pressure forward and use a reasonable rear wing which would then help with the wake generation. Keeping the wing and diffuser decoupled to limit total downforce would require careful wording and policing of the rear of the car. Some form of required vertical surface might be used to help with wake. Just require the rear crash structure to be vertical and e.g. 350mm high by 1000mm wide sat above the diffuser but finishing 20mm in front of the diffuser so the crash structure can't be incorporated in to the diffuser.

[Scania]

todays F1 disgner make the cars have very low drag created by the area behind the car, most of the drag are from the wings, it make less drag but also make the air flow behind the car is very confused, it make other cars can't get close, so over take is lesser & lesser.

The over Taking group said that it must provide some clean air to the follower, so they design CDG wing and the cars we can see today, but over taking is still hard.

How about that: force the design of the car should have a perpendicular, flat & seal up plane at the rear of the car, it will make a low pressure area behind the car, so the follower can catch up the air flow just like the day before.

[WhiteBlue]

On your 4th point whiteblue. How would you measure the downforce? To make sure that at no point the car goes over the 1 metric ton (just for example). The only reason i ask is that if this was the rule then the teams would run at exactly 1 metric ton (all agreed?), so if some external fact eg air pressure effected this and took it over the limit, we would after the race see people being disqualified for going over (which nobody wants).

I agree with the Idea, its just how you do it thats the problem.

All you need is a sensor to each wheel and a bit of programming to the ECU. Obviously you would take out inertial forces with another sub routine of the evaluation program which would be done via the existing accelerometers. You then monitor the downforce and you have a public penalty table for transgressions. Race control or live timing can even tell the viewers automatically with the timing which penalty is applicable to each car at any time during the race should the team mess up. You can have adjustable wings as FiA proposed to fine tune downforce in order to stay away from the limit.

If you don't like that kind of adjustable wing or automatic time penalty you can have an integrator which gives you two limits which could be used like a yellow and red card in soccer. Yellow is a warning that you are in serious trouble and have to pit to reset your downforce. If you exceed red you get a meat ball with your number.

I like this train of thought and (as a complete non-physicist) it's precisely something I've been pondering recently.

- I see the sensors streaming to race control and the car's pit all the time.
- The maximum allowable downforce would only apply at a very high speed (300km/h?) since the object of the exercise is to significantly reduce the disruptive effect of turbulence and it follows that at all lower speeds the area of turbulence would be commensurately smaller and less intense.
- The max downforce limit would not apply at all during braking since the time during which the accelerometers would report 'excessive' downforce in this situation would be momentary and then only when braking from 300km/h and above.
- I see the maximum allowable downforce being very significantly lower than at present. If, say, 1500kg is imposed on the car at 300km/h, my model would see that being reduced to 750kg. Still 150kg or so above the static weight of the car. (I should add that I don't know how much downforce the current crop of cars develop at 300km/h so I do stand to be corrected here.)
- This approach cuts through all the prescriptive suggestions as exemplified in the CDG wing proposal and from the numerous pundits! The trouble with prescriptive rules is that they challenge creative engineers to think of ways round the rules and the spirit, Eg Brawn et al last year.
- Instead, it proposes a single measure which will be totally transparent in real time.
- The teams can have all the wings (read advertising space), winglets and underbody magic they like... so long as they don't exceed the downforce limit.
- Thus this means drag will be reduced.
- Straight line speed will be increased.
- Braking distances will be increased. (Less downforce).
- Cornering speeds will be reduced.
- Turbulence behind a car will be significantly decreased.
- The cars will be harder to get the best out of.
- Thus we will see a greater emphasis on driver skill.
- Overtaking will become more possible.

I will concede that there is a large element of artificiality in this major proposal but we have many items of artificiality right now with more being proposed. We're not about to go back to Formula Libre but my fear is that if the tinkering continues we'll wake up one day and find that F1 has become a spec formula a la NASCAR.

This proposal allows the possibility of all sorts of innovation. But it still puts an undodgeable clamp on notching up that enemy of interesting racing, monster downforce and its hand maiden, turbulence that would lift a freight train off its tracks.

I shall now go and hide in the bunker!

Missing from your list of benefits is the massive reduction of air friction which would translate into fuel saving. Cornering forces would come down somewhat to perhaps less than 3 G and that would benefit the chances of women racers making it into F1. They typically have problems with the up to 5G that the current formula puts on the neck muscles.

[Scania]

todays F1 disgner make the cars have very low drag created by the area behind the car, most of the drag are from the wings, it make less drag but also make the air flow behind the car is very confused, it make other cars can't get close, so over take is lesser & lesser.

The over Taking group said that it must provide some clean air to the follower, so they design CDG wing and the cars we can see today, but over taking is still hard.

How about that: force the design of the car should have a perpendicular, flat & seal up plane at the rear of the car, it will make a low pressure area behind the car, so the follower can catch up the air flow just like the day before.

sorry for my bad english level....




I'll try to make a 3D sketch in a few days

[kilcoo316]

This is sort of what I was proposing previously but was poo-poo'd on

In effect you're looking at a version of the Lotus 79 without the skirts or the big rear wing.

Or you could move the floor's centre of pressure forward and use a reasonable rear wing which would then help with the wake generation. Keeping the wing and diffuser decoupled to limit total downforce would require careful wording and policing of the rear of the car. Some form of required vertical surface might be used to help with wake. Just require the rear crash structure to be vertical and e.g. 350mm high by 1000mm wide sat above the diffuser but finishing 20mm in front of the diffuser so the crash structure can't be incorporated in to the diffuser.

I'm not a fan of the diffuser as it stands.

A much, much more gradual ramp is preferable - proper ground effect aerodynamics as opposed to the flat floor approach.


A potential idea may be to have "two diffusers"... both ahead of the rear wheels under the sidepods. That would mean underbody downforce is generated at approx the aero-centre, and is insensitive to the car ahead.

Then specify the front and rear wing are long chord single elements. There is no central rear diffuser, and the wheel track is widened to get the tyres outside of the sidepods/floor.

[Just_a_fan]

This is sort of what I was proposing previously but was poo-poo'd on

In effect you're looking at a version of the Lotus 79 without the skirts or the big rear wing.

Or you could move the floor's centre of pressure forward and use a reasonable rear wing which would then help with the wake generation. Keeping the wing and diffuser decoupled to limit total downforce would require careful wording and policing of the rear of the car. Some form of required vertical surface might be used to help with wake. Just require the rear crash structure to be vertical and e.g. 350mm high by 1000mm wide sat above the diffuser but finishing 20mm in front of the diffuser so the crash structure can't be incorporated in to the diffuser.

I'm not a fan of the diffuser as it stands.

A much, much more gradual ramp is preferable - proper ground effect aerodynamics as opposed to the flat floor approach.


A potential idea may be to have "two diffusers"... both ahead of the rear wheels under the sidepods. That would mean underbody downforce is generated at approx the aero-centre, and is insensitive to the car ahead.

Then specify the front and rear wing are long chord single elements. There is no central rear diffuser, and the wheel track is widened to get the tyres outside of the sidepods/floor.

I.e. the lotus mentioned above