Reducing wake by adding fenders on formula car

[second]

With the twist that you either cover the front OR rear tires with some kind of light bodywork. By covering I mean that the tire is covered by some fender type bodywork that maybe covers the wheel all around except from the outside side so tire changes can be done without removing any parts.

The goal being to reduce the turbulent wake. Which could improve the reduction of downforce while following other car.

Would it be better to cover the front or rear wheels in this case? We know that covering all the wheels is less drag and less lift compared to having all the wheels open. But what if you look at situations where the fronts are covered vs the rears being covered? Using f1 2017 regs as an example.

[Vyssion]

What you're basically saying is to take an open-wheel car and turn it into a closed-wheel car....?
Of course that would reduce vehicle and wheel drag - but that's not what F1 is; it is open-wheel racing and part of what makes it difficult is the aspect of dealing with the turbulent wake of each wheel.

That being said, in answer to your question about whether you "had" to pick one set of wheels (front or rear) to shroud, which would be better to do so? The answer, in my opinion, is the front wheels. The reason for this is that their wake influences all of the bodywork behind them and so improving that wake will improve the performance of the aerodynamic devices behind them.

[PlatinumZealot]

I read the topic as reducing wake by adding feathers.

Im tired. I will make my exit now.

[second]

Sorry for the super late reply.

What you're basically saying is to take an open-wheel car and turn it into a closed-wheel car....?
Of course that would reduce vehicle and wheel drag - but that's not what F1 is; it is open-wheel racing and part of what makes it difficult is the aspect of dealing with the turbulent wake of each wheel.

I'm just thinking about an idea how to reduce the effect of dirty air and allow the car behind follow closer. In other words make the car output less dirty air. It is all for the sake of technical discussion, not about ideological definitions about what is f1.

That being said, in answer to your question about whether you "had" to pick one set of wheels (front or rear) to shroud, which would be better to do so? The answer, in my opinion, is the front wheels. The reason for this is that their wake influences all of the bodywork behind them and so improving that wake will improve the performance of the aerodynamic devices behind them.

My understanding is that covering the front tires helps the car itself. Covering the rear tires would help reduce the effect of dirty air behind the car. Assuming the rear tire covers were designed with the aim of reducing dirty air in mind.

Also my other fear is that if you cover the front wheels it allows to create even more delicate aero shape for the body which produces bigger downforce numbers but is even more susceptible to the effects of dirty air when following other car (which uses similar wheel covers). If you cover the rear wheels there is probably only a drag reduction for the car itself but the air coming off of the car could be made less turbulent..?

I mean, for the sake of technical argument we don't even need to fully cover the wheels. Could something like the indycar "rear bumpers" be used to reduce dirty air from the rear tires? Or is the dirty air coming from the rear tires even that big of a deal when looking at the full picture of dirty air caused by the car for the following car? Does it matter that?

[riff_raff]

Did you have something like this in mind?

[Vyssion]

It is all for the sake of technical discussion, not about ideological definitions about what is f1.

Fair enough mate, I mistook your motive.

My understanding is that covering the front tires helps the car itself. Covering the rear tires would help reduce the effect of dirty air behind the car. Assuming the rear tire covers were designed with the aim of reducing dirty air in mind.

One thing to keep in mind is that by the time the air hits the rear part of the car, the air is already extremely turbulent. Designing rear shrouds would allow said turbulent air to hit the stagnant surface rather than a rotating tyre which would definitely not "add" any more vorticity/disturbances to the airflow, but I doubt would actually serve to "reduce" the dirtiness of the air.

Also my other fear is that if you cover the front wheels it allows to create even more delicate aero shape for the body which produces bigger downforce numbers but is even more susceptible to the effects of dirty air when following other car (which uses similar wheel covers). If you cover the rear wheels there is probably only a drag reduction for the car itself but the air coming off of the car could be made less turbulent..?

First question here you ask isnt true. Wheel shrouds arent really designed for increasing downforce of the wheel area (there may be some flow on effects by the reduction of turbulence allowing other aerodynamic components to p roduce more downforce, but the shrouds themselves wont really do that) They will serve to reduce the massive wake that a rotating tyre generates and possible counteract the lift that a rotating wheel can sometimes generate.
The air will be less turbulent from shrouding the rear wheels, yes - but it would be less turbulent if you shrouded the fronts too - you would still generate a bluff body type of wake behind the shrouds as well.

I mean, for the sake of technical argument we don't even need to fully cover the wheels. Could something like the indycar "rear bumpers" be used to reduce dirty air from the rear tires? Or is the dirty air coming from the rear tires even that big of a deal when looking at the full picture of dirty air caused by the car for the following car? Does it matter that?

Wheels account for over 50% of an open-wheel racecar's total drag. There are a total of 6 vortices which a rotating wheel generates: two counter rotating vortices which roll up in front of the contact patch area and generate some amount of lift, two counter rotating ones at the top of the wheel which roll up around the top and induce cylinder-like separation around the wheel, and two more at half height of the wheel which are counter rotating, however, they can swap to roll upwards or downwards depending on the inflow direction.



If it was me in charge of aerodynamics for my team, I would purposefully want to create as much of a turbulent wake as I possibly could so that it would be incredibly difficult for cars to pass me. Some may argue that as "unethical for racing" or "potentially dangerous" but Im not here to "play fair"... Im here to win.

As far as the aero rules are concerned now, 2017 regulations will see bigger wakes generated and so I think that there will be even less overtaking than before. One thing that I do think could help though would be to make the front wings much less sensitive to oncoming turblent air flow, and then reduce the rear wing's performance to very little, and then make the underbody and diffuser rules almost free reign so that you can get stupid performance numbers from under the car. This way, there is not as much air being flicked up and over following cars, and it is kept low to the ground - so although it is turbulent, it will still be hitting the car and not going over it.

[second]

Did you have something like this in mind?

http://musclecarfilms.com/sitebuilder/i ... 27x350.jpg

No, nothing like that. What I'm thinking is wheel covers of any type imaginable that would reduce the dirty air effects coming from the car. Be that on the front or rear, neither or both, full covers, partial covers, mix of those two. And/or shapes in front or behind the tire, what kind of shapes. Indycar rear bumpers, lmp style rear covers, redbull x2011 front wheel covers, formula e style bits in front of the front wheels, or formula e this kind of bits in front of rear wheels: http://www.autosport.com/news/report.php/id/108286

But I'm not interested into choosing one design. I'm interested whether the whole idea even works. Could covering the front AND/OR rear wheels with certain style of wheel covers reduce the effects of dirty air and allow closer racing? Or does it make much difference. Assuming that we can force certain shapes everybody must use.

For the sake of clarity by wheel covers I mean everything from fenders to brakeducts etc.. English is not my first language.

One thing to keep in mind is that by the time the air hits the rear part of the car, the air is already extremely turbulent. Designing rear shrouds would allow said turbulent air to hit the stagnant surface rather than a rotating tyre which would definitely not "add" any more vorticity/disturbances to the airflow, but I doubt would actually serve to "reduce" the dirtiness of the air.

That is a good point but I feel it is little bit different what I was suggesting. I'm willing to totally ignore the aerodynamic effects of the wheel shrouds for the car itself. I'm only interested to making the air coming off the car and off the rear tires less turbulent. Hoping it would allow for closer racing. So my idea is to figure out whether covering the wheels in some way could help with that.

Wheels account for over 50% of an open-wheel racecar's total drag.

I see this actually as a good thing. The more draggy the car is the more pronounced the slingshot effect (slipstreaming) is. If the slipstreaming effect is spot on then you basically have a drs which is not artificial. The issue is of course that slipstream reduces drag and downforce both so it does bad things when cars try to follow each others in corners. But maybe there is a good value somewhere that works well enough for both?

If it was me in charge of aerodynamics for my team, I would purposefully want to create as much of a turbulent wake as I possibly could so that it would be incredibly difficult for cars to pass me. Some may argue that as "unethical for racing" or "potentially dangerous" but Im not here to "play fair"... Im here to win.

So if I interpret this correctly there IS a shape f1 rules could mandate to maximaly reduce the turbulence of the air coming off from the car? In other words take away as much as possible the car designer's ability to make the air coming off from the car as turbulent as possible. Which is my whole point for this thread

Iirc f1 banned the wheel rim covers because they added turbulence. Would it be possible to design wheel rim covers that reduce the turbulence of the air coming off from the wheels? And then force everybody to use them...

As far as the aero rules are concerned now, 2017 regulations will see bigger wakes generated and so I think that there will be even less overtaking than before. One thing that I do think could help though would be to make the front wings much less sensitive to oncoming turblent air flow, and then reduce the rear wing's performance to very little, and then make the underbody and diffuser rules almost free reign so that you can get stupid performance numbers from under the car. This way, there is not as much air being flicked up and over following cars, and it is kept low to the ground - so although it is turbulent, it will still be hitting the car and not going over it.

I don't want to go offtopic with f1 2017 rulesets but the reason I'm a bit against having totally free underbody regulations is that it puts a lot of money and research into something nobody will ever see because the underside of the car is rarely if ever seen. I'd rather have free top body regs because at least then the money spent is there for everybody to see and all the cars would look different.

[Vyssion]

If you want a single line answer, of course you can design shrouds or other things in order to reduce the dirtiness of the air coming off the back of an F1 car. But no one would (unless forced) because it is not in the interest of teams to allow people behind them to gain an advantage.
Your original question was whether covering the front or the rear would be better. The quick and simple answer is that it is better to cover both; cover the fronts if you want to mildly reduce the wake whilst gaining some efficiency increase on your car and cover the rears to pretty much gain nothing for you, and help people behind you.

On to your last message then:

One thing to keep in mind is that by the time the air hits the rear part of the car, the air is already extremely turbulent. Designing rear shrouds would allow said turbulent air to hit the stagnant surface rather than a rotating tyre which would definitely not "add" any more vorticity/disturbances to the airflow, but I doubt would actually serve to "reduce" the dirtiness of the air.

That is a good point but I feel it is little bit different what I was suggesting. I'm willing to totally ignore the aerodynamic effects of the wheel shrouds for the car itself. I'm only interested to making the air coming off the car and off the rear tires less turbulent. Hoping it would allow for closer racing. So my idea is to figure out whether covering the wheels in some way could help with that.

Looking at the Red Bull x2011, this car was the brainchild of Adrian Newey of what an F1 car may look like given completely open aerodynamic regulations (and also for fun in Gran Tourismo) - it even uses a similar active aero suction fan like the old Brabham BT46 Fan Car did in order to suck it right into the road. This car did use wheel shrouds with the aim of reducing the aerodynamic turbulence (and by definition, drag) of the wheels. You will still have one or two of the vortices forming, however 2/6 is a large reduction. The problem you run into with shrouds, however, is that it no longer becomes a case of having a relatively "straight" vortex being spun off the wheel and heading right to the following car. You end up turning the surface into a stagnation pressure region and effectively a downforce generating body which will push the air upwards.

Wheels account for over 50% of an open-wheel racecar's total drag.

I see this actually as a good thing. The more draggy the car is the more pronounced the slingshot effect (slipstreaming) is. If the slipstreaming effect is spot on then you basically have a drs which is not artificial. The issue is of course that slipstream reduces drag and downforce both so it does bad things when cars try to follow each others in corners. But maybe there is a good value somewhere that works well enough for both?

The reason the wheels are such a large contributor for drag is due to those 6 vortices I mentioned in the previous reply - they generate a ton of turbulence and pressure drag etc. which will always exist simply because "physics". Aerodynamics plays a lesser role the slower that a car is going with most aerodynamic differences between cars pretty much being negligible below 100km/hr. Of course following is always worse, but if you are looking to make overtaking in corners easier, then the best thing would be to widen the track of the cars and allow a sort of DRS-equivalent of active suspension; mechanical grip is much more reliable and less dangerous than aerodynamic related grip in corners.

If it was me in charge of aerodynamics for my team, I would purposefully want to create as much of a turbulent wake as I possibly could so that it would be incredibly difficult for cars to pass me. Some may argue that as "unethical for racing" or "potentially dangerous" but Im not here to "play fair"... Im here to win.

So if I interpret this correctly there IS a shape f1 rules could mandate to maximaly reduce the turbulence of the air coming off from the car? In other words take away as much as possible the car designer's ability to make the air coming off from the car as turbulent as possible. Which is my whole point for this thread

See first line in this reply --- F1 regulations do not allow for wheel shrouds and so it cannot be done at the moment and if they were allowed, I would still want to make as dirty wake as possible. You will always have dirty air simply because "physics" with aerodynamics. Equal and opposite reaction etc etc I'm sure you know about, but I do think that there should never be a full control aero package thing because then you end up with V8 Supercar Racing in Australia where every team gets a control chassis and you cant tell them apart while theyre racing unless you look at the symbol on the grill....

Iirc f1 banned the wheel rim covers because they added turbulence. Would it be possible to design wheel rim covers that reduce the turbulence of the air coming off from the wheels? And then force everybody to use them...

Not quite... There is naturally a lot of air coming in from the brake air intake and then pushed through to the outside of the wheel. Having these covers allowed the air to be directed as well as serve to reduce the turbulence you generate from air spinning up inside the rim spokes as the wheel rotated. They were banned for safety reasons mainly in that during pit stops, there were often issues where the rim cover wouldnt attach/spin up properly when changing a tyre and would then come off during racing. FIA was going through a "safety first" period and banned them to make this less of a potential hazard.

As far as the aero rules are concerned now, 2017 regulations will see bigger wakes generated and so I think that there will be even less overtaking than before. One thing that I do think could help though would be to make the front wings much less sensitive to oncoming turblent air flow, and then reduce the rear wing's performance to very little, and then make the underbody and diffuser rules almost free reign so that you can get stupid performance numbers from under the car. This way, there is not as much air being flicked up and over following cars, and it is kept low to the ground - so although it is turbulent, it will still be hitting the car and not going over it.

I don't want to go offtopic with f1 2017 rulesets but the reason I'm a bit against having totally free underbody regulations is that it puts a lot of money and research into something nobody will ever see because the underside of the car is rarely if ever seen. I'd rather have free top body regs because at least then the money spent is there for everybody to see and all the cars would look different.

If you want the top visible parts of the car to be all intricately designed and optimised and look aggressive/stylish etc, then you will always have issues with air being flicked up by the wings and body... can't really get around that.... It may serve to get teams to invest hugely on underbody aerodynamic gains, whilst regulating the top even more to ensure that the top aero looks better than it currently does, but is incapable (to a point) of producing high downforce on its own and so equalising total downforce with the numbers generated by the tunnels and diffuser.

[second]

If you want a single line answer, of course you can design shrouds or other things in order to reduce the dirtiness of the air coming off the back of an F1 car. But no one would (unless forced) because it is not in the interest of teams to allow people behind them to gain an advantage.
Your original question was whether covering the front or the rear would be better. The quick and simple answer is that it is better to cover both; cover the fronts if you want to mildly reduce the wake whilst gaining some efficiency increase on your car and cover the rears to pretty much gain nothing for you, and help people behind you.

Do you have any numbers how big effect could be had with just rear wheel covers? I'd guess putting a number on the turbulence of the air is tricky. But it would be useful to know if this effect would be in the single digit percentages or double digits. Or something.

The reason the wheels are such a large contributor for drag is due to those 6 vortices I mentioned in the previous reply - they generate a ton of turbulence and pressure drag etc. which will always exist simply because "physics". Aerodynamics plays a lesser role the slower that a car is going with most aerodynamic differences between cars pretty much being negligible below 100km/hr. Of course following is always worse, but if you are looking to make overtaking in corners easier, then the best thing would be to widen the track of the cars and allow a sort of DRS-equivalent of active suspension; mechanical grip is much more reliable and less dangerous than aerodynamic related grip in corners.

Yeah, this is what I've been thinking too. Although I'm not sure what you mean like "drs-equivalent of active suspension"?

My understanding is that active suspensions would allow cars to follow closer because the floor of the car can be kept at ideal ride height. I did read some symonds interview where this was mentioned. The car following behind loses downforce because the downforce on top of the car is reduced which reduces the load on the springs which in turn makes the car ride little higher - which in turn reduces the downforce coming from the floor which makes the car ride higher again... Active suspension in some form could help alleviate that as I see it.

See first line in this reply --- F1 regulations do not allow for wheel shrouds and so it cannot be done at the moment and if they were allowed, I would still want to make as dirty wake as possible. You will always have dirty air simply because "physics" with aerodynamics. Equal and opposite reaction etc etc I'm sure you know about, but I do think that there should never be a full control aero package thing because then you end up with V8 Supercar Racing in Australia where every team gets a control chassis and you cant tell them apart while theyre racing unless you look at the symbol on the grill....

I was not talking about making f1 spec racing. Lots of the parts are already pretty regulated. The floor, the nose, the rear wing. If adding some bits to the rear which need to be of certain shape I don't really see it making f1 spec racing. Especially if this would allow making the rules more free.

Also I'm not talking about eliminating dirty air completely. It is not possible. But if there are ways to reduce it then I find it worth thinking about. Like I said earlier it doesn't have to be full blown historic jaguar lmp style covered wheels. If indycar styled bumpers for example help even a bit then to me it sounds like idea worth looking at.

Not quite... There is naturally a lot of air coming in from the brake air intake and then pushed through to the outside of the wheel. Having these covers allowed the air to be directed as well as serve to reduce the turbulence you generate from air spinning up inside the rim spokes as the wheel rotated.

I don't understand what you are saying here. Are you saying standardized wheel covers would require standardized wheels as well to work? Or even standardized brake ducts?

[Vyssion]

If you want a single line answer, of course you can design shrouds or other things in order to reduce the dirtiness of the air coming off the back of an F1 car. But no one would (unless forced) because it is not in the interest of teams to allow people behind them to gain an advantage.
Your original question was whether covering the front or the rear would be better. The quick and simple answer is that it is better to cover both; cover the fronts if you want to mildly reduce the wake whilst gaining some efficiency increase on your car and cover the rears to pretty much gain nothing for you, and help people behind you.

Do you have any numbers how big effect could be had with just rear wheel covers? I'd guess putting a number on the turbulence of the air is tricky. But it would be useful to know if this effect would be in the single digit percentages or double digits. Or something.

I wouldnt even begin to speculate sorry mate - I would imagine that in terms of just the drag of the wheel on its own, it would be reduced significantly, but as to the effect it would have on reducing the overall turbulence of the air on the full vehicle, I wouldn't have a clue beyond saying that there would be some small reduction at least.

The reason the wheels are such a large contributor for drag is due to those 6 vortices I mentioned in the previous reply - they generate a ton of turbulence and pressure drag etc. which will always exist simply because "physics". Aerodynamics plays a lesser role the slower that a car is going with most aerodynamic differences between cars pretty much being negligible below 100km/hr. Of course following is always worse, but if you are looking to make overtaking in corners easier, then the best thing would be to widen the track of the cars and allow a sort of DRS-equivalent of active suspension; mechanical grip is much more reliable and less dangerous than aerodynamic related grip in corners.

Yeah, this is what I've been thinking too. Although I'm not sure what you mean like "drs-equivalent of active suspension"?

What I mean by that is that at the moment, there is a button which drivers press which opens the upper rear wing flap on straights to aide in overtaking when they are within 1.000 second of the car in front. To apply that same concept to active suspension, the driver would press a button when they were measured as being perhaps 1.000 second behind a car in front on the previous straight before a section of tight corners or S-curves (for example) and when the driver presses the button, there is a module which is carried that allows for active suspension to be used through the turns before deactivating and suspension returning to normal once the turns are over - and hopefully after overtaking.
TLDR; button turns on active suspension instead of moving a rear wing flap.

Not quite... There is naturally a lot of air coming in from the brake air intake and then pushed through to the outside of the wheel. Having these covers allowed the air to be directed as well as serve to reduce the turbulence you generate from air spinning up inside the rim spokes as the wheel rotated.

I don't understand what you are saying here. Are you saying standardized wheel covers would require standardized wheels as well to work? Or even standardized brake ducts?

Nah, I was saying that as the wheel rotates, the rim (with spokes) generates a lot of turbulence which is then pushed out and back of the rim. The wheel hub covers helped reduce this, but they also served a dual purpose in allowing some air to bleed out at specific sectors of the hub to direct some of the brake duct air. A standardised wheel hub thing wouldn't require a standard anything else - teams would just have to find a way to make their brake ducts work symbiotically with the hub.

[PlatinumZealot]

Did you have something like this in mind?

http://musclecarfilms.com/sitebuilder/i ... 27x350.jpg

I like this idea. If optimized it would reduce wheel wake to a good level while still being open wheel. Definitely a thinking engineer's solution to the "problem. "

[riff_raff]

How about the rear wheel covers on this FIA Group C formula car?

[toraabe]

How about the rear wheel covers on this FIA Group C formula car?

https://s-media-cache-ak0.pinimg.com/or ... 084a8e.jpg

Group C cars were designed around groundeffect. They had large venturi tunnels underneath. When Ross Brawn and John Piper designed the XJR 14, they made an invention to seal off the floor better than before. They made it narrower towards the floor, with a flap underneath. http://www.ultimatecarpage.com/images/l ... R-14_1.jpg This increased the downforce level.

[Just_a_fan]

Tony Southgate had a similar device on the XJR-6. He made the car's bodywork slightly narrower than the rules allowed and fitted an outward facing strip. This strip helped to reduce flow under the side of the car and improved downforce.

The clever thing about it was that it was impossible to copy without wholesale changes to the car - everyone else ran their bodywork to the maximum the rules allowed.

[toraabe]

So .. why are they so afraid of re-introduce groundeffect in F1 ? and reduce the wings.
I don't know....