Brake Ducts, Tire Cooling, and beyond

[AR3-GP]

And this is setting aside the difficulty in managing constant pressure in the break circuit upon the fluid changing volume while heated and cooled.

Well, the Mclaren drivers struggle a lot with braking...

[AR3-GP]

For it to absorb heat and then dissapate, it’s essentially dynamic braking that’s been around on railroad locomotives for 80 years.

I don't understand the connection. The phase change isn't going to cause any wheel deceleration. It's not an E&M phenomenon.

What a thermal imaging camera would also show, is where that is being dissapated and would be east for RB to call out. They haven’t done so. Last I recall, any form of dynamic braking on the front axle is illegal anyway.

What does Red Bull need to "call out" and why? Is PCM illegal? What they have shown is this:

According to AMuS, the team has turned to thermal imaging cameras to capture the temperature of the tyre cooling ducts on the MCL39 when the drivers come in for their pit stops with the focus primarily on the rear tyres as they generally overheat more quickly than the fronts.

The German publication claims Red Bull have noted ‘many blue areas around the brake vents on the McLaren tyres, while all the other cars showed a lot of orange and red’ with the team coming to the conclusion that it is ‘impossible’ to cool the tyres that well with just air alone.

The "brake vents" are the inlets and the outlets. It would suggest very cool brakes, somehow, or some kind of isolation or storage of the heat from the brake disc.
https://www.planetf1.com/news/thermal-c ... en-mystery

Everyone can claim to “design a fluid” or “use a material”. But what are these materials? Call some specific ones out. F1 very rarely if ever has “invented” their own materials, usually stealing commercially available materials from aerospace (it’s only exotic in the sense joe public has never heard of it). Would be even less likely in the cost cap era.

The argument doesn't depend on whether an F1 team invented it or they found someone that makes the materials. The first video suggest that B Pillar Sport youtube owner wrote a masters thesis on a phase changing material for Mclaren. So it is possible. There are other sources where you can look. It's not vaporware.
https://www.i-tes.eu/it/blog/4/i-materi ... alore.html

[Hoffman900]

He wrote a phase changing material for batteries. Read the rules and see how you can make it work for brakes.

B Sports very well may have done this to call attention to his thesis for self promotion to seek a job or better job.

[Hoffman900]

I have a running joke with friends that Newey gets credit for inventing everything

He really does!

Actually Newey did not even invent the Red Bulls Blown-Diffuser. It was basically a copy of Ferraris intended diffuser for 1998. Unfortunately Carbon and heat-protecting was not at the level at that time to make it work, so Rory Byrne came up with the Periscope-Exhaust, but the famous first Blown-Diffuser Newey used at Red Bull was actually an almost 1-1 copy of this system.

High noses: Harvey Postlethwaite and Jean-Claude Migeot in 1990 for Tyrell

Blown diffusers: Jean-Claude Migeot in 1982 for Renault (also when they debuted pnuematic valve springs)

Active Suspenion: Peter Wright for Lotus in 1983 based on road cars that had it in 1981. The Williams system was derived from an ambulance self leveling system refined by Frank Dernie and Paddy Lowe

Venturi floors: Tony Rudd, Peter Wright, Shawn Buckley, and Martin Ogilvie. 1977 for Lotus.

Outwash front wings: unknown. Frank Dernie is on record saying they took the idea from Champ Car

Underfloor strakes like you see on the current cars: developed by Reynard for Champ Car. Appeared in the mid 1990s. Likely Malcolm Oastler and Bruce Ashmore.

Jim Hall and his cadre of GM engineers have to get big credit. They really beat everyone to the punch.

Double diffuser: some argue Rory Byrne in 1998. On the Brawn, Saneyuki Minegawa

Carbon brakes: Gordan Murray after seeing the BF Goodrich, Dunlop licensed designed ones on the Concorde. Done in consultation with Dunlop. 

Carbon monocoque: Hercules Aerospace / Steve Nichols in conjunction with John Barnard. 1981

etc.

[AR3-GP]

He wrote a phase changing material for batteries. Read the rules and see how you can make it work for brakes.

It's not the work of a minute. Someone at an F1 team would have spent weeks if not months researching and implementing it if it was done. None of us will be able to replicate that amount of effort in our spare time.

[Andi76]

He really does!

Actually Newey did not even invent the Red Bulls Blown-Diffuser. It was basically a copy of Ferraris intended diffuser for 1998. Unfortunately Carbon and heat-protecting was not at the level at that time to make it work, so Rory Byrne came up with the Periscope-Exhaust, but the famous first Blown-Diffuser Newey used at Red Bull was actually an almost 1-1 copy of this system.

High noses: Harvey Postlethwaite and Jean-Claude Migeot in 1990 for Tyrell

Blown diffusers: Jean-Claude Migeot in 1982 for Renault (also when they debuted pnuematic valve springs)

Active Suspenion: Peter Wright for Lotus in 1983 based on road cars that had it in 1981. The Williams system was derived from an ambulance self leveling system refined by Frank Dernie and Paddy Lowe

Venturi floors: Tony Rudd, Peter Wright, Shawn Buckley, and Martin Ogilvie. 1977 for Lotus.

Outwash front wings: unknown. Frank Dernie is on record saying they took the idea from Champ Car

Underfloor strakes like you see on the current cars: developed by Reynard for Champ Car. Appeared in the mid 1990s. Likely Malcolm Oastler and Bruce Ashmore.

Jim Hall and his cadre of GM engineers have to get big credit. They really beat everyone to the punch.

Double diffuser: some argue Rory Byrne in 1998. On the Brawn, Saneyuki Minegawa

Carbon brakes: Gordan Murray after seeing the BF Goodrich, Dunlop licensed designed ones on the Concorde. Done in consultation with Dunlop. 

Carbon monocoque: Hercules Aerospace / Steve Nichols in conjunction with John Barnard. 1981

etc.

Double Diffuser Rory Byrne 1998 is not quite right. It was 2005, but it was far less efficient because a) the "holes" were missing and b) it was attached to the side of the central diffuser, not above it. However, the basic idea was the same, namely to make better use of the central tunnel, which was allowed to be higher in 2005. The 2009 model was a further development of this idea.



Even though I still think it's possible, and in my opinion McLaren has definitely developed something new and extreme in brake cooling in the last two years (burning brakes without this reason would not be worth any F4 team), I would like to throw something else into the room. If they use such a (for F1-new) material it should be very, very light. Because ultimately, at least as I understand the application of PCM in this respect, you use this ADDITIONALLY. Which means McLaren would put extra weight where you want it last from a vehicle dynamics point of view. Far away from the center of gravity at the four outer points of the car.

[DiogoBrand]

About some of the ideas we've seen:
1. A bimetallic strip would be considered a movable aerodynamic device;
2. A phase changing material would not have nearly the cooling capacity needed to last a 90 minute race;
3. Even if you had a pump continuously circulating brake fluid to the brakes and back, it would need to have a massive radiator and a large flow rate to make a difference in brake temperature, considering how much energy the brakes absorb.

If I had to guess, I'd say the more simple explanation is the most likely: They're managing the airflow inside the wheels in a way that either cools the brakes really well, or in a way that isolates the wheels from most of the brake heat.

I remember that during the Barcelona pre-season test in 2022 they had one of the best cars, only to become one of the worst at Bahrain because of poor brake cooling. So either their brake issues led to them developing the best cooling solution on the grid, or they were already working on a clever solution that at the time didn't work well and it backfired.

We should also not forget about the other aspects that lead to less tyre overheating, like suspension geometry and car aero, where I think they have an advantage as well.

[Red Rock Mutley]

Apologies for being late to the discussion on movable aero devices. Did the discussion reach a conclusion? Given the movement in certain body parts, the front wing for example, there appears to be a great deal of *cough* flexibility.

Consider a simple system: Create a structure within the brake duct that restricts air flow. It is unsupported at one end, and thus has a degree of elasticity. As the flow increases, so the structure bends (presents less of a restriction).

So far, this behaviour closely resembles the front wing. Many of the flaps and ticks around the brakes and hub are unsupported, so there is already a degree of accepted aero elasticity.

Now, support this structure with a thermal component that controls the elasticity of the flow restrictor. Bimetallic strips are the obvious go-to choice, but let’s make it interesting by choosing a vapour chamber. One end of the vapour chamber is in contact with the brake calliper, while the other end “supports” the air flow restrictor. (I envision a vapour chamber responding more rapidly to temperature changes, and the location and design of the “input” surface are highly configurable.) As the vapour chamber expands with temperature, it would need to be arranged to make the air flow restrictor more compliant to air pressure.

[For a more complex system, how about a sandwich - a restrictor plate, attached at one end, bonded to a bimetallic strip to control compliance, bonded to a vapour chamber to conduct heat from a remote location to the restrictor.]

The aim is not to do this complex aero switch, but simply clip the max input heat input by modulating the cooling by a small degree. Obviously, this system cannot completely negate the effects of air pressure acting on the restrictor, only mediate it. Neither can it cool the brakes completely (which would be undesirable). However, the aim is to lessen the peak heating of the brake components by backing off the restrictor when the brakes are exceptionally hot. The size of the brake duct puts an upper limit on the maximum amount of cooling. The characteristics of the flow restrictor puts a low limit on the minimum amount of cooling.

2 questions,

- Firstly, would this be illegal? If so, what rules does it contravene?
- Secondly, what would be the tell-tale sign of a car running this system?

[Hoffman900]

About some of the ideas we've seen:
1. A bimetallic strip would be considered a movable aerodynamic device;
2. A phase changing material would not have nearly the cooling capacity needed to last a 90 minute race;
3. Even if you had a pump continuously circulating brake fluid to the brakes and back, it would need to have a massive radiator and a large flow rate to make a difference in brake temperature, considering how much energy the brakes absorb.

If I had to guess, I'd say the more simple explanation is the most likely: They're managing the airflow inside the wheels in a way that either cools the brakes really well, or in a way that isolates the wheels from most of the brake heat.

I remember that during the Barcelona pre-season test in 2022 they had one of the best cars, only to become one of the worst at Bahrain because of poor brake cooling. So either their brake issues led to them developing the best cooling solution on the grid, or they were already working on a clever solution that at the time didn't work well and it backfired.

We should also not forget about the other aspects that lead to less tyre overheating, like suspension geometry and car aero, where I think they have an advantage as well.

I agree. A thermal image camera would show where this air is going.

The best way to manage tire heat is via aerodynamics and chassis set up. The other is driving style.

RB is like The Sun, and knows they can put nuggets of maybe true maybe not information out there and let places like these, F1 twitter / media sphere have a field day. They know Mclaren isn’t going to respond

[DiogoBrand]

Apologies for being late to the discussion on movable aero devices. Did the discussion reach a conclusion? Given the movement in certain body parts, the front wing for example, there appears to be a great deal of *cough* flexibility.

Consider a simple system: Create a structure within the brake duct that restricts air flow. It is unsupported at one end, and thus has a degree of elasticity. As the flow increases, so the structure bends (presents less of a restriction).

So far, this behaviour closely resembles the front wing. Many of the flaps and ticks around the brakes and hub are unsupported, so there is already a degree of accepted aero elasticity.

Now, support this structure with a thermal component that controls the elasticity of the flow restrictor. Bimetallic strips are the obvious go-to choice, but let’s make it interesting by choosing a vapour chamber. One end of the vapour chamber is in contact with the brake calliper, while the other end “supports” the air flow restrictor. (I envision a vapour chamber responding more rapidly to temperature changes, and the location and design of the “input” surface are highly configurable.) As the vapour chamber expands with temperature, it would need to be arranged to make the air flow restrictor more compliant to air pressure.

[For a more complex system, how about a sandwich - a restrictor plate, attached at one end, bonded to a bimetallic strip to control compliance, bonded to a vapour chamber to conduct heat from a remote location to the restrictor.]

The aim is not to do this complex aero switch, but simply clip the max input heat input by modulating the cooling by a small degree. Obviously, this system cannot completely negate the effects of air pressure acting on the restrictor, only mediate it. Neither can it cool the brakes completely (which would be undesirable). However, the aim is to lessen the peak heating of the brake components by backing off the restrictor when the brakes are exceptionally hot. The size of the brake duct puts an upper limit on the maximum amount of cooling. The characteristics of the flow restrictor puts a low limit on the minimum amount of cooling.

2 questions,

- Firstly, would this be illegal? If so, what rules does it contravene?
- Secondly, what would be the tell-tale sign of a car running this system?

My understanding of the bimetallic strip concept, if I got it right, is that I create a blockage for cooling to allow the tires to heat up quickly, and once they're up to temperature I open up some sort of passage to cool the tires and keep them at a constant temperature, sort of like an engine thermostat.

My understanding is that this would be illegal and considered as a movable aero device. For example, the F-duct was a similar sort of concept, redirecting air through a different passage depending on conditions, only it was activated by a part of the driver's body rather than something that reacted to the conditions by itself. If it was mechanically activated I'm quite sure it would count as a movable aero device, which is why I believe a bimetally strip that acted this way would be illegal.

As for your second question, I don't know what would be the signs. It's just guessing at this point because of the supposed behaviour of the tires reaching operating temperatures fast but then keeping stable temps rather than overheating, which makes some people think it's an on/off system, but no concrete evidence so far.

[ringo]

The other thing about MCL39 is the front suspension which can indirectly lead to better rear axle tyre temperature management.

It was discussed in another thread the possible variable toe angles with the steering geometry.

If the car has toe-out on the front axle, it will understeer more in the corners and demand less lateral load on the rear axle. This will manage rear tyre temperatures much easier than a toe-in setup that has sharper turn is and more oversteer balance.

So this suspension geometry could be a piece of the puzzle. It may not be a silve bullet like phase change materiasl, it could be a combination of toe-angle control, differential control, KERS control, brake hardware size, cake tin design and duct design. It can be a lot of little things adding up to manage temperatures within a 20 degree C band.

Norris may be finding the car tricky in qualifying because it has more of an understeer setup which protects the rear tyres more. And maybe the drivers can manage by how much lock they use in the car. Maybe after a certain steering angle, there is an effect for quicker or slower warm up.

[michl420]

My input for this disscusion.
We talking her about a big amount of energy. To cool some ml of brake fluid in a classic layout change nothing. And some overly complicated thing with brake lines is a safety risk that I don´t think mclaren or the FIA would risk.

Liquid cooling of the brakes are forbidden. Is the airflow blockage for cooing air (brake drum) part of this brake?
But I don`t think it has anything to do with a fluid.

About this PCM Material, I also don`t think it can take the amount of heat for a stint. But the theory about just absorb the peaks and release it later looks practicable.

They do absorb as much energy as possible with the MGUK anyway.

Red bull claims that it is impossible to do it with air, that indicates that it has nothing to do with the compromis qualy/race, otherwise the other teams would just go for more air. (But I am not sure the RB argument is true/fact)

Maybe they run just a different brake material that works in a lower temperatur range.

I don´t think the top speed deficit has something to do with it, because the visual part of the brake duct look very normal.

[tok-tokkie]

My understanding of the bimetallic strip concept, if I got it right, is that I create a blockage for cooling to allow the tires to heat up quickly, and once they're up to temperature I open up some sort of passage to cool the tires and keep them at a constant temperature, sort of like an engine thermostat.

My understanding is that this would be illegal and considered as a movable aero device. For example, the F-duct was a similar sort of concept, redirecting air through a different passage depending on conditions, only it was activated by a part of the driver's body rather than something that reacted to the conditions by itself. If it was mechanically activated I'm quite sure it would count as a movable aero device, which is why I believe a bimetally strip that acted this way would be illegal.

As for your second question, I don't know what would be the signs. It's just guessing at this point because of the supposed behaviour of the tires reaching operating temperatures fast but then keeping stable temps rather than overheating, which makes some people think it's an on/off system, but no concrete evidence so far.

But if a driver activated system is legal then all they need is a temperature gauge and a manual switch & they have pretty well full control over the temperature.

[AR3-GP]

They do absorb as much energy as possible with the MGUK anyway.

The Mercedes AMG team has the same PU.

Red bull claims that it is impossible to do it with air, that indicates that it has nothing to do with the compromis qualy/race, otherwise the other teams would just go for more air. (But I am not sure the RB argument is true/fact)

The performance of the other 8 teams suggest that it is a valid argument.

Maybe they run just a different brake material that works in a lower temperatur range.

The brake caliper, disc, etc are open source components. That means Mclaren must share the design with the other teams. So it wouldn't be this. The other teams have access to the design.

I don´t think the top speed deficit has something to do with it, because the visual part of the brake duct look very normal.

The amount of flow restriction between the inlet and the outlet of a duct depends on the path between the inlet and the outlet. So area on its own does not tell the whole story. "cooling" (and more of it), tends to be related to drag however and Mclaren seem to have "extra cooling". It's not the whole story, but it can be some of it.

[AR3-GP]

What is it?