Brake Ducts, Tire Cooling, and beyond

[FittingMechanics]

^ agreed

In an era of cost caps and CFD run time, how teams allocate finite resources to aspects of the car is the whole game. It was a gamble for Mclaren to take away man power from other parts of the car to focus on brake ducts (and everything that comes with from design, calibrating CFD, to manufacture), but it seems to have paid off.

And they had those problems with overheating brakes for two years in a row, now with hindsight it's obvious they were trying to push the envelope. At the time most of the fans thought it embarrassing to have such issues on an F1 car.

[Watto]

How do you already know it's completely legal? Can you show me the link to where this is stated?

There are multiple media reports saying it was inspected and cleared after the Miami GP, I think these things tend to leak pretty quickly if they found something. Supposedly a report it will come out soon.

Is perhaps possible that there is something there the FIA is unaware of currently that may come out in the sure but in the absence of anything there than I think you have to consider what ever McLaren is doing is completely legal. There isn't that I am aware even any concrete evidence of something wrong.At least with the mini DRS last year there was video of something to base it off here there is nothing. So I think that's clear enough McLaren are in the clear.

Part of a projection in materials "advance" by those sites pushing PCM element and its legally applied use OR versions of that, appear to be muddying the waters as to its status.

In reality, from the images we can all see of fitment to that car, then it just looks to be very detailed thinking, development and targeted design, manufactured to bring critical performance (performance in just how effective the brake cooling etc is) to this aspect of the car.
Properly carried out ..... it seems over and above other teams existed designs .... looks to have produced margin for the team to utilise intelligently to raise whole chassis performance sphere, but very particularly in longer range management of peak/critical tire upper temperature sensitivity.

F1 is littered though with somewhere where complexity seemed to come out of nowhere before everyone copied. Front wings, barge boards and so on they became the norm I don't tend to think there is anything different going on here.

Even on PCM unless there is something black and white it's illegal - Vanja touched on his in the McLaren thread/Twitter. He thinks PCM are illegal but if the material never changes phase it's probably he thinks okay.

[Watto]

^ agreed

In an era of cost caps and CFD run time, how teams allocate finite resources to aspects of the car is the whole game. It was a gamble for Mclaren to take away man power from other parts of the car to focus on brake ducts (and everything that comes with from design, calibrating CFD, to manufacture), but it seems to have paid off.

And they had those problems with overheating brakes for two years in a row, now with hindsight it's obvious they were trying to push the envelope. At the time most of the fans thought it embarrassing to have such issues on an F1 car.

Yep and honestly what ever McLaren have done I'd be bothered (unless it was something really against the rules) if the FIA came out and banned it F1 just because 'reasons' has always been about pushing the envelope it's part of what I enjoy about it. I think there are times when I think crackdowns on loopholes have been pretty poor . Plenty of spec series of racing to watch if that's what you want.

Just accept McLaren have done an exceptionally good job here.

[hollus]

Guys, remember your “I think”, “if” and “maybe”s.
Being unreasonably assertive only annoys everyone.

[TeamKoolGreen]

^ Screenshot from that video

Look at how close the shrouding around the rotor is to the rotor itself.(top left) That is insane. There's no room for air. There's something other than air cooling going on there.

https://i.postimg.cc/XYxqgSfz/brake33.jpg

No it's not. That's lacking in knowledge by the observation.

The disc rotor is primarily cooled by contact of the surrounding air right close to the surfaces both internally (through vent holes in structure) and the friction surface itself.

If that close flow of air is exchanged frequently and to as much capacity as they can generate through there, then its more effective than generally "wafting" air around inside the drum indiscriminately.

I meant the comment somewhat tongue in cheek. The shroud is basically as close as it can be without touching the rotor. This is not an orthodox way of doing it and if you think it is, then it isn't me lacking knowledge.

[AR3-GP]

^ Screenshot from that video

Look at how close the shrouding around the rotor is to the rotor itself.(top left) That is insane. There's no room for air. There's something other than air cooling going on there.

https://i.postimg.cc/XYxqgSfz/brake33.jpg

No it's not. That's lacking in knowledge by the observation.

The disc rotor is primarily cooled by contact of the surrounding air right close to the surfaces both internally (through vent holes in structure) and the friction surface itself.

If that close flow of air is exchanged frequently and to as much capacity as they can generate through there, then its more effective than generally "wafting" air around inside the drum indiscriminately.

I meant the comment somewhat tongue in cheek. The shroud is basically as close as it can be without touching the rotor. This is not an orthodox way of doing it and if you think it is, then it isn't me lacking knowledge.

It is a very interesting observation. We know that there are 3 "shells". The first shell covers the rotor. The second shell is an intermediate layer with the flow diverting vanes (silver, potential high thermal conductivity), and the third is the outer carbon shell. It seems like Mclaren's concept would have much more airflow between the silver basket and the interior most brake rotor shield. As illustrated below:

[Farnborough]

I'd view it from the "opposite" direction. In that there are very many example of extracting heat from metal surface with air that all display, through well established calculation and routine, that keeping the air very close to the surface containing heat will enhance extraction efficiency of that process.

Air cooled motorcycle, any automotive radiator "flutes" etc all routinely do this in utilisation of OPTIMUM dimension for that aspect.

That being the case, then to first supply, secondly to extract that air after it's been heated is a balance that is being enacted here. Previously we've possibly not seen that level of calculation and focus in this area of application.

That, IF completed to the best of it's design, will then leave a different volume @ different temperature gradient between primary "shroud" and (as you note AR3-GP) the silver assembly .... this to again have it's efficiency competently analysed and optimised to give that next barrier function in preventing latent disc rotor heat reaching to the outer cake tin material.

It just looks like intelligent deep dive analysis and quantified design to mitigate the effects.

The projection of changing from warming the wheels to capping heat transmission appears to be false. Probably leading to that speculation (for that's what it is) of moving a no phase change materials, that don't immediately seem to be there.

[Farnborough]

^ Screenshot from that video

Look at how close the shrouding around the rotor is to the rotor itself.(top left) That is insane. There's no room for air. There's something other than air cooling going on there.

https://i.postimg.cc/XYxqgSfz/brake33.jpg

No it's not. That's lacking in knowledge by the observation.

The disc rotor is primarily cooled by contact of the surrounding air right close to the surfaces both internally (through vent holes in structure) and the friction surface itself.

If that close flow of air is exchanged frequently and to as much capacity as they can generate through there, then its more effective than generally "wafting" air around inside the drum indiscriminately.

I meant the comment somewhat tongue in cheek. The shroud is basically as close as it can be without touching the rotor. This is not an orthodox way of doing it and if you think it is, then it isn't me lacking knowledge.

I too was being facetious and so Touchè on that aspect.

It is though discussion of detail about in depth specifics of what we can see in these images, in reality it seems no more than equivalent to other cooling strategies used across various components on these cars. I believe we are just looking at very detailed and intelligent application by McL in this area.

[ringo]

^ Screenshot from that video

Look at how close the shrouding around the rotor is to the rotor itself.(top left) That is insane. There's no room for air. There's something other than air cooling going on there.

https://i.postimg.cc/XYxqgSfz/brake33.jpg

Visually the thing that stands out with the McLaren is that the area where the hub contacts the rotor has it's own duct.
The other cars do not have this. The rotor is transferring a lot of heat to the spline that it's meshed and driven with.
Blowing fresh cool air to this section would take away a lot of heat. Followed by clever ducting to usher the hot air out would make for a very efficient cooling package.

[venkyhere]

If we keep aside PCM and the cleverness of 'air pathways' for a moment (Redbull insists that no way air alone is removing heat, but not sure with what conviction they are saying this) ,
Two points :
1. The data point that 'McLaren warms it's tyres faster than others' => I am not sure whether it's anything technical or whether the outlap by the drivers is pretty aggressive (as I have observed) where the fear of 'not using up the tyres too much' is absent in McLaren's case, since their cooling at full-tyre-load, is so effective.
2. At the risk of sounding like a total idiot, what if some heat is extracted via the driveshaft itself ? (material used / the way it splines up with the brake disc and the gearbox) - is it totally stupid to think of the oil in the gearbox as a large enough heat sink to take 'more than normal conduction' heat from brakes (because there is a cooling jacket for the GB anyway) ? is there any OSC standard restriction on the driveshaft design and material used ?

[Alexf1]

McLaren brakes now formally cleared by FIA: https://www.the-race.com/formula-1/what ... nspection/

[Anony Mous Engineerd]

I'm not surprised! The phase change stuff was too wacky to be real. Also, suppose you think about sodium-filled exhaust valves that use a solid metallic sodium that melts to a liquid inside a hollow valve stem, the phase change is used to improve heat transfer, not as an insulating material. The liquid sodium has a crazy high specific heat, and the sloshing helps transfer heat from the valve side to the tappet side.

I'd bet the carbon fibre in the ducts have an insulated ceramic component, or a new ceramic coating that is really insulating and ensures the heat transfer is primarily controlled by convection, not conduction. Kudos to the McLaren Brake team...

[kentonspr]

No it's not. That's lacking in knowledge by the observation.

The disc rotor is primarily cooled by contact of the surrounding air right close to the surfaces both internally (through vent holes in structure) and the friction surface itself.

If that close flow of air is exchanged frequently and to as much capacity as they can generate through there, then its more effective than generally "wafting" air around inside the drum indiscriminately.

I meant the comment somewhat tongue in cheek. The shroud is basically as close as it can be without touching the rotor. This is not an orthodox way of doing it and if you think it is, then it isn't me lacking knowledge.

It is a very interesting observation. We know that there are 3 "shells". The first shell covers the rotor. The second shell is an intermediate layer with the flow diverting vanes (silver, potential high thermal conductivity), and the third is the outer carbon shell. It seems like Mclaren's concept would have much more airflow between the silver basket and the interior most brake rotor shield. As illustrated below:

I wonder if the rotor and shield being so close together influences the pumping action of the brake rotor on the air touching the surface. Kind of like a reverse Tesla turbine. Accelerate the mass of air around the rotor in a circular motion and it will move to the outside of the rotor just like the central cooling holes. I'm no engineer, but it would seem like having more space around the rotor would just create more turbulence inside the shield and rely on ram air to move it.

It could potentially allow for them to use a smaller inlet for cooling the rotor by relying less on the ram air effect, allowing more air to be available for rim cooling.

Fun to speculate about even if I'm most likely way off.

[dialtone]

I think fundamentally the reason why RedBull is puzzled is because this is pure physics.

The break is developing heat. The air coming in has to move it out, the primary limitation is the size of drum and heat capacity.

I think the efficient thing to do is to increase the heat exchange area by efficiently moving heat from the center to the outside, and clearly they are using fiber glass to isolate the heatshield.

The most efficient way to move heat with lower weight is heat pipes like in CPUs and GPUs, these use a PCM inside the chamber that turns into gas to get into the radiator/heatsink and then is cooled by the airflow. These pipes can be extremely small and you only need a few of them to transfer lots of heat as the phase change absorbs a ton of energy.

I think that is just about what mcl is doing, or thereabouts. They are moving heat where they can dissipate it more efficiently and shielding the area they want to keep cooler.

I think it makes sense overall if done that way, it’s not magic, you just can’t have cooler areas without something else getting hotter or bigger. Other teams have probably already figured out how it works and it’s just a matter of time.

[ringo]

PCMare illegal for cooling.
Agreed there is fancy airflow through the braking system.
The cool air that redbull claimed to have seen was coming out of the exhaust duct at the rear of the inside of the wheel.
The duct seems to be split in two.
So they raised alarm about this not being possible without water cooling.
What it may have been is just bypassed air. Just as a Jet turbine engine bypasses air flow for increased thrust. Ovbiously for different reasons here. But cooler air coming out can only be from a portion of the air not coming into contact with the hot surfaces in the brakes.