Red Bull: Front Hub Rule Clarification

Coming straight after another Technical Directive from the FIA, Red Bull have again had one of their designs ruled on by Charlie Whiting. It’s now the Front hub design that has stretched the rules to the point where a clarification was required. Uniquely Red Bull duct air through the front hub to vent it out through the wheel for aerodynamic benefit. This appears to contravene the regulations on air ducts forming part of the brake system.

All teams use a hollow front stub axle (hub); the hub spins on bearings within the upright. Although hollow, the hub is not normally used to duct airflow to the brakes, instead air is ducted around the upright to enter the drilled brake disc.
In Red Bulls case the hub has air fed through it and then exits through two areas on the hub outboard of the disc. Firstly through drillings in the larger diameter section of hub and secondly in an open section outboard of the threads that hold the wheel nut on.
The air that vents through these outlets will exit through the centre of the wheel and does not really contribute to any brake cooling function. It’s clear a lot of effort has been expended on these vents, particularly the outboard vents. The six vents waist away the outer section of hub to almost nothing. These show how the inner section of the nut retention system being pointed to divert the flow out of these vents. Reinforcing the fact that these are vents and not simply drillings for weight saving.
I suspect the aim of this ducted flow is to aid the general flow out of the wheel. This will help improve the airflow that passes around the wheel off the front wing, which will reduce drag and probably also aid airflow to the rear of the car for more rear downforce. But any gain will be a small one, just a few points of aero efficiency. As with the tyre squirt slots in the rear of the floor, not even tenth of a second performance gain. Often with aero gains, it’s a compound effect of several gains in many areas, which really brings lap time benefit.
Back in 2009 teams fitted static wheel fairings to the front wheels; these also aided the airflow around the front tyre. These fairings were banned for 2010, by a series of rules that prevented any bodywork\brake duct outboard of the wheel. These rules are the same ones that Red Bulls design appears to contravene.
Three sections of regulation 11.4 ban these fairings and apply to the current Red Bull design. Firstly that any air ducts are considered part of the brake system, secondly that the air duct must not rotate and lastly that the duct must not protrude outboard of the wheel nut. Regulations do not consider brake ducts as bodywork, also the rules are not specific what constitutes a brake duct, be it carbon ducting or the hub itself. Equally the rules do not demand any air duct forms any form of brake cooling function, but all are merely considered part of the brake system.
Red Bulls hub is clearly acting as an air duct, regardless of not being any form of brake cooling. We can then apply either the ‘rotating’ wording to all of the drillings in the hub or the ‘outboard of the wheelnut’ to the outer drillings.
Red Bull have now been asked to close off these drillings, which has been done temporarily with tape. For subsequent races Red Bull may choose to redesign the hub or make a more permanent solution to replace the tape used in Canada.

11.4 Air ducts :
Air ducts around the front and rear brakes will be considered part of the braking system and shall not protrude beyond :
‐ A plane parallel to the ground situated at a distance of 160mm above the horizontal centre line of the wheel.
‐ A plane parallel to the ground situated at a distance of 160mm below the horizontal centre line of the wheel.
‐ A vertical plane parallel to the inner face of the wheel rim and displaced from it by 120mm toward the car centre line.

Furthermore :
‐ When viewed from the side the ducts must not protrude forwards beyond a radius of 330mm from the centre of the wheel or backwards beyond a radius of 180mm from the centre of the wheel.
The ducts may not rotate with the wheels nor may they, or any of their mountings, protrude axially beyond the outer face of the wheel fastener.
‐ No part of the car, other than those specifically defined in Articles 12.8.1 and 12.8.2, may obscure any part of the wheel when viewed from the outside of the car towards the car centre line along the axis of the wheel.

13 thoughts on “Red Bull: Front Hub Rule Clarification

  1. I think much more efficient would be redesign the wheel itself. Today at the aftermarket you have several wheels done with carbon fiber in some part or entirely. Other incredible new tech is the carbon fiber injected… Even done in metal, today you have several ‘diabolical’ milling cutter machines with several axles to improve the aerodynamics of the set… I think one time or another Mr. Newey will make his own wheels… If somebody needs help, hire me! I have several ideas in this field… Can I post here one link to my blog about one innovative wheel design done by myself? Best Regards

    • It’s a nice idea, but the regs are pretty tight regarding, material and aerodynamic performance.

      12.3 Wheel material :
      Wheels must be made from AZ70 or AZ80 magnesium alloys.
      12.4.4 Wheel dimensions and geometry must comply with the following specifications :
      ‐ The wheel design cannot be handed between left and right designs.
      12.4.5 No wheel material is permitted in the following exclusion zones :
      ‐ A concentric cylinder of diameter 305mm and length 115mm positioned with its inner face lying in the same plane as the inboard face of the front wheel.
      ‐ A concentric cylinder of diameter 305mm and length 25mm positioned with its outer face lying in the same plane as the outboard face of the front wheel.
      ‐ A concentric cylinder of diameter 305mm and length 100mm positioned with its inner face lying in the same plane as the inboard face of the rear wheel.
      ‐ A concentric cylinder of diameter 305mm and length 30mm positioned with its outer face lying in the same plane as the outboard face of the rear wheel.
      12.4.6 When viewed perpendicular to the plane formed by the outer face of the wheel and between the diameters of 120mm and 270mm the wheel may have an area of no greater than 24,000mm2.

      • Oh, it’s true; I’ sorry because already knew about the magnesium alloys obligatoriness but forgot these regulations that are a shame! Whatever I still think the aero design of the wheels can be much improved if people think out the box… Some very simple aero tricks found in nature almost everywhere and also underwater that can improve several percent any aero device as proved several times are not seen in F1; for me this is a mystery… People at F1 don’t like simple nature’s tricks, no problem, we can go more complicated: if the designs cannot be handed between the left and right designs; could be an advantage; because most of the tracks are clockwise… Yeah… Aside having to deal with the breaks, all the aerodynamic philosophy of the car must be redone… But it’s the price of glory in the top of the motorsports when any tenth of second is the difference between the glory and the defeat… Anyway there always room to improvements but it’s difficult to do something outside the engineering pipeline; as the odds that someone at motorsports will hire me are very, very, very tiny; I already tried to send designs some years ago two times; I hope somebody more creative will take the charge to do more advanced wheels out there! Regards

      • This is a reply to Lawrence, but the commenting system as it is, there’s no other way.

        Lawrence having clockwise tracks doesn’t mean a thing. Sure, the amount of degrees, by which the car will rotate around a vertical axis, will always be: left+360°=right. So the car wil always do a full circle more to the right (clockwise) than to the left.

        Though that doesn’t mean a thing, it’s the configuration of the corners, that really sets it appart. You can still make a track that depends more on the right pair of the tires, than on the left,w hile being clockwise.

        Furthermore, making a directional rim will only mean the balance will be WAY off. All of the benefits will be more than negated on the other side. Sure, aerodynamicaly they could be improved, using dimpled surfaces and simmilar solutions, but that’s not as radical, as turbine wheels. Nor is it understood as good as making the spokes into vanes, to extract the air.

  2. Good article Scarbs, RB really pushing the limits here and no doubt elsewhere. Was this originally cleared informally with Charlie, as were the ‘holes’?

    I thought the pointy end of the hub was to facilitate quick wheel changes?

  3. I think Craig’s referring to the black cone, just visible behind the openings in the hub, not the gold cone.

  4. Exactly.

    Lawrence if i remember correctly, the wheels have a quite tightly defined cross area and shape, so no, they couldn’t make improvements. They made aerodynamic wheels (turbine lookig, basicly extracting air out), but they more or less got banned with the static outboard wheel fairings.

      • As I cannot reply above, will do it here… First thanks for the reply because I love have someone to discuss respectfully this matter… But as before I disagree, even getting in count your point of view that seems somehow linked with motorsports or being myself out of the process, why? Because you don’t need radical turbine designs to make difference at time table. Maybe one very small difference, even making the car balance off at the straights; despite that the car design itself could be modified to take even more advantage of the asymmetrical wheels balance being asymmetrical too.
        If the track is asymmetrical, the car must be too. I know in fact it’s already asymmetrical due to adjustments in the setup; but I think that if you want some advantage with these very restrictive regulations you will have to be (much) more aggressive designing the car.
        And the aero approach is ‘only’ one aspect of the wheel design. I still think that the structure of the wheel can also be improved with the ‘diabolical’ drilling cut machines that could make the rim and spokes lighter and with smaller cross section area with great precision that is needed.
        And please, I’m don’t want to say that what I wrote here is absolute unerring, but raise some ideas to people think about it. I always try to keep my mind open; is how I did some innovative designs that I hope you saw in my blog; sometimes you start developing one improvement and ends with other much better that in fact wasn’t linked with the first one.
        Somebody notice that Ferrari changed they long date wheels supplier BBS to OZ like the champion RB7? Even don’t knowing if some economical aspect was imperative to this supplier change; don’t think so because Maranello have lots of resources to change so long date supplying relationship only because money; for me means that the Italians saw technical advantage choosing the OZ wheels. Regards.

      • That’s what i was trying to say, even if the unbalanced car would be beneficial in some corners (the right ones for example), the benefits would be more than negated when going through the other (left) corners. I mean it does depend on the design type, but at the moment i can hardly think of anything else but air shaping shapes, which are HIGHLY dependant on the rotation direction of the rim. Which is different on left and right sides.

        If you’d take into account this difference, for example desigining the brake cooling system for push-pull operation on one and pull-push operation on the other side it would have a massive effect further back on the car.

        Scarbs are there any rules about cars (the bodywork) having to be symmetrical accross the vertical middle plane?

        Yes, a n-axis (n being as high as it goes, it’s up to 9, maybe even further up now) you can make incredibly complex shapes. But that doesn’t help you that much, when you have actually quite tightly defined shapes.

        And furthermore, why machine when you can forge, which produces lighter and/or stronger rims. The aero benefit, that you’d get from machining, is here compensated with less unsprung weight, a lighter wheel has a lower mass moment of inertia, i.e. it spins up and down easier (it needs less energy), so your braking and acceleration improve, etc.

        I did saw some of your designs in your blog, mainly the V8. Merely saying to spin it up to 24k rpm is a whole different thing, than actually achieving it. With forced induction much more so (i hope i did see correcty that you intended a supercharging system). Using rotary valves, the way the McLaren system was developing a few years back, makes forced induction even harder to achieve. And why did you have 8 exhaust ports per side? Using a rotary valve one is more than enough per cylinder. Ergo you’d only have 4 exhaust ports per side of a V.

        And using supercharging (pulley driven air pump charging that is) is going to be in my oppinion used less and less in the future. I suspect variable geometry turbines to become the norm in gasoline engines, even though the exhaust gasses are MUCH hotter (something like 1200°C vs. 800°C in a diesel i was told), the development of electricaly driven turbines (the turbine side acts as a generator, the compressor has a motor attached) would also negate practically all of the lag, that we have now (using a capacitor in the connection would enable you to spin up the compressor very quickly, on demand basicly).

        Etc. etc.

        Though you must understand, i’m not a designer, i’m studying mechanical engineering, so i’m more of a pesimist (though i am optimistical by nature) when it comes to new designs. I’d like to see them proven at least with numbers, if not with prototypes 🙂

  5. This witch hunting process is getting out of hands! They don’t know what to do to stop Red Bull, they just won 2 races this year and the FIA got nervous again. Thanks god technical innovations such as the f-duct or exhaust have not got banned!

  6. Primoz, nothing prevents you to machine one forged part, getting the best of both worlds; sure you will have to make entirely new designs already done to be machined, I don’t think there are ‘room’ to machine actual wheels.
    About the asymmetrical design; I can’t make you see what you don’t want… If you steer 360 degrees more to one side, working properly to making the turns faster to this side will compensate the loss to the other side easily if done properly. Other aspect is that in one clockwise track, the faster and most important turns are ALWAYS clockwise too… (less Suzuca because its unusual shape)The ant-clockwise are mostly slow ones when the wheels spins slower so the disadvantages will be even less noticeable.
    Only trying it with nice concepts once our physics models can’t predict what really happens in real world, we will see what happens. Yes, anybody that wants to try it will have lots of work without any success guaranteed, maybe will have several defeats before one win, but that’s the price of glory. What happened with 90% of the concepts that ruled F1 in the past.
    Please leave this comment about my engine at my blog… Whatever…
    About my engine, as said here before I don’t want to make one wheel or engine myself; my objective is always propose new approaches to automotive designs… Rotary valves are a much better once you make it work properly, smaller, lighter, simple, compact, much less movable parts and vibrations, no coils or pneumatic valves needed, requires less power to work; so you can rev it up much easy than traditional pop-up valves that needs pneumatic valves above 15k rpm. Why nobody did it? I can’ tell why but have my ideas about, mostly because the people that tried before struggled with gasketing and wearing problems but this is another matter. The benefits to a top end sport car worth theses ‘unsolved’ problems; unsolved because people have to think different to make it nice. If everything else fails, you still can put one conventional engine on it.
    This one that you saw was done in 2005 and as I deliberately didn’t explain exactly how any part works you got several aspects wrong. Having 2 exhaust ports don’t mean that you have 2 valves in each cylinder… But being rotary, you can have as many as you want… There are a reason to that and there are not any supercharger or turbo compressor because one simple aspect; it’s don’t needed. As you are the smart guy, you will figure out everything by yourself because as I said I don’t want to explain everything. At last I want to see some real interest to make it to show all the details.
    But don’t be upset because you will have another chance! The all new race spec to Pulse 2 – Cyborg Eagle is almost online… The renderings are done… 7 years make lots of difference. Soon I will post it!
    Nobody more than me wants to make this engine and other innovations proposed in my blog but it is not my call even doing everything that I could.
    The same fellings that prevents you about any new concepts makes the automotive evolution very slowly and my designs freeze at my blog.
    If fact, what real innovation you saw last years in carmakers portfolio? Nothing! If you didn’t figure out how my engine really works is because the same problems occurred doing the previous rotary valved engines developing; yours imagination are blocked with what you already learned to pop-up valves that is useless. Think outside the box! So the possibilities will be endless and you will see that what apparently don’t work can be much better than you think.
    Scabsf1, I sorry because I have been off topic; I though could be rude don’t answering our friend.
    Best regards.

  7. I’ll be quick here, i need to study and go to bed soon. Mainly about your engine design and valves:

    I never said they are not good. Heck, i’d love to see them developed further. Sadly it was the FIA that banned them. They were invented by an australian guy, who got funding by McLaren, and once FIA gave the ban, McLaren stopped with the funding.

    Turbocharging would be hard, becuase you’d have to seal the whole intake tract. With an N/A engine you just have to seal between the cylinder and the rotary valve, when the intake port of the valve is not lined up woith the cylinder intake port, the charging air might as well be vented out thorugh the exhaust or something (when compressing and expanding, both the intake and exhaust ports in the valve would be ‘open’ relative to each other, in the simplest sealing form). With turbocharging you’d be losing pressure that way.

    Though for a normal car, having fewer moving parts might not be as needed. DIesels go up to only about 5k rpm anyway, normal poppet valves are very well developed, some are singing songs of doom to the internal combustion engine (electric cars and all), etc. Might just not be worth the development costs. Desigining something to be used in normal road cars takes a whole different approach, than to use in F1.

    That’s the reason for the lack of innovation in road cars. Things just need to be tested out really, REALLY well. They have to wrok, at iether -40°C (standard cold start temperature) or +40. Then some components must endure temps all the way up to 100, 200, 500, even 1000+°C. So from -40 to +1000 in some cases. On the other hand teams heat up the F1 engines before cranking, because cold they are basicly siezed up.

    It’s usually the small guys that drive true innovation, that then gets picked up by the big guys. The big guys just don’t want to take the risk of a major flop. Maybe i’m looking at everything too much with this view, which probably isn’t good. Even though i have some ideas, that basicly don’t exist on the market at the moment in that shape or form (not car related).

    On one hand we also need some constructive criticism, it shows the flaws of the designs, which, if the criticism taken properly, forces us to fix the error. Or just give up, which is a less favourable choice.

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