Brake Ducts, Tire Cooling, and beyond

[vorticism]

...mixing cooling air inside the collector to manage temperatures within it; adding ambient air to the hot outflow of the brake disc.

Such as...


As stated, at the front of the W16's rear disc outflow collector there appears to be an additional feed. You’d expect the only thing feeding into the collector is the brake disc, and rely on insulation to control its temperature, as we’ve seen on RB and Mclaren ducts, yet the Merc collector looks like it has two infeeds: the brake disc and an additional duct. Adding ambient air inside the collector would dilute the brake outflow and cool the collector pesistently between braking events, and this would presumably negate the need for insulation.

[AR3-GP]

That's a great drawing.

[AR3-GP]

It might be old news, but I've never noticed the rear brake duct outlet of the Mclaren before. IT seems to have 3 separate airflow compartments.

[AR3-GP]

From Spanish GP '25. On the left is Mercedes who struggles with rear tire temperature management. On the right is the team with the best rear tire management of the top 4. Rear brake duct exit outlined in yellow. Mercedes duct exit has single channel of air exiting the duct. Mclaren duct exit has 3 divided channels inside the exit. Mclaren's outlet is so much bigger than Merc's. I wonder if there is a connection.

[AR3-GP]

Something that was missed was that last year Ferrari introduced a new front brake duct in Miami.
Reportedly to reduce the amount of heat radiating from the brakes into the front tires. They made a step towards Red Bull in race pace after that weekend. Coincidence?

[AR3-GP]

It almost looks like variable size blanking panels can be installed on the RB21 front brake bodywork. Could this be done to control the amount of heating of the tires with brake disc heat?

[AR3-GP]

RB19 rear brake duct. 3 Compartments like the MCL39.

[SB15]

https://i.postimg.cc/3NKVhQ55/image.png

From Spanish GP '25. On the left is Mercedes who struggles with rear tire temperature management. On the right is the team with the best rear tire management of the top 4. Rear brake duct exit outlined in yellow. Mercedes duct exit has single channel of air exiting the duct. Mclaren duct exit has 3 divided channels inside the exit. Mclaren's outlet is so much bigger than Merc's. I wonder if there is a connection.


https://i.postimg.cc/rFx64TMT/image.png

There is a connection. @vorticism made a fantastic post on how the Mercedes brake cooling operates and it's not only because the air is being extracted from very small outlets, but most of the heat from the brakes are being insulated in the brake hub.

Mercedes is prioritizing aero efficiency but it's useless when you discover that tyre cooling gives you a major performance gain. Mclaren advantage isn't about just the large cooling outlets and what they're doing isn't anything magical, it's actually very simple with a technology that's very common:

Here's my analysis/theory: You know how Laptops uses specially designed copper pipes, with thermal pads under the heatsink with big openings for the fan's airflow, to allow for heat extraction in the rear and sides?

If you look at the Mclaren brakes, it's not that far off from my analogy.

[SiLo]

I wonder if one of the channels is just a free air channel, it doesn't cool anything specifically, but by injecting unblocked airflow into a exit right next to the other, it help increase the speed of the exiting air surrounding it, making it more efficient?

[BMMR61]

Something that was missed was that last year Ferrari introduced a new front brake duct in Miami.
Reportedly to reduce the amount of heat radiating from the brakes into the front tires. They made a step towards Red Bull in race pace after that weekend. Coincidence?

https://cdn-9.motorsport.com/images/mgl ... -deta.webp

To be fair Miami was the big, exceeding all expectations, 2024 McLaren upgrade, with a raft of new components. At the time, the brake ducts were considered the minor part of the upgrade. From memory there were in subsequent weekends, tweaks to airflow around brake ducts on multiple occasions. They've probably been working on this area since mid 2023 when they started to become a regular podium contender and the performance gains have been many and incremental. Just my 5c worth.....

[AR3-GP]

I wonder if one of the channels is just a free air channel, it doesn't cool anything specifically, but by injecting unblocked airflow into a exit right next to the other, it help increase the speed of the exiting air surrounding it, making it more efficient?

It could be. I also wonder if the more outboard channel(s) (closer to the tire sidewall), are more likely to be a free air channels, creating an "air curtain" to limit the amount of brake duct heat which is flowing against the sidewall of the tire. If the brake duct exhaust were being exposed directly to the sidewall, I think that would contribute to more heating of the tires. If this is true, then one can see how the Mercedes design seems less optimal. They mix the brake disc exhaust and a free stream in the brake disc collector, but that air is heated and expelled right next to the sidewall of the tire. It seems to lack the air curtain.

[AR3-GP]

Exit 1- brake disc collector (hot air)
Exit 2 - shell 2 airflow (or caliper cooling)
Exit 3 - shell 3 airflow (free air)


shell 2 and shell 3 could be flipped with exit 2 and exit 3

[AR3-GP]

It could be. I also wonder if the more outboard channel(s) (closer to the tire sidewall), are more likely to be a free air channels, creating an "air curtain" to limit the amount of brake duct heat which is flowing against the sidewall of the tire. If the brake duct exhaust were being exposed directly to the sidewall, I think that would contribute to more heating of the tires. If this is true, then one can see how the Mercedes design seems less optimal. They mix the brake disc exhaust and a free stream in the brake disc collector, but that air is heated and expelled right next to the sidewall of the tire. It seems to lack the air curtain.

https://i.postimg.cc/3r98yD5g/image.png

[AR3-GP]

[AR3-GP]

I wonder if more attention can be paid to how the heat radiates outward from the back of the car. There are many external heat sources including the engine, the cooling system, the exhaust pipes, the front brake duct exits and the rear brake ducts exits. How do they conduct and convect heat towards the back of the rear tires? If you take a thermal snapshot, what is the temperature of the air entering the rear brake ducts, the air hitting the face of the tire, and the temperature of the air near the inner sidewall?