Brake Ducts, Tire Cooling, and beyond

[Alexf1]

Indeed, in heating up the tyres the McLaren doesn't really stand out. It's the "thermostat" function of keeping the tyres on the ideal temperature while pushing 100% is phenominal compared to all competitors. Really impressive stuff. Especially as the difference is huge and rear tyre overheating problems have been a part of F1 since the Pirelli tyres. So teams had this problem for ages and to have this big an advantage is in the region of Mercedes dominance and RB18/19. Like all here I'd be very interested to know what this game changer is

[basti313]

We are assuming that McLaren is somehow using brake heat to heat up the tires, then once they're up to temperature they're isolating them to prevent overheating, but is there any evidence that they're doing something special to bring the tires up to temperature?

Good point. No, I do not see anyone really struggling with getting the tires up to temperature. We barely see double warmup laps even in cold conditions. It is rather an issue, that the tires do not stay in their window, or to hit this window.
So to me this speaks against any shenanigans with switches, they just cool better. And with more tire cooling you can use the tire more which makes you better in Q.

A few points to consider:
1. In my interpretation a bimetallic strip would be considered a movable aerodynamic device and, therefore illegal, so I don't think that is it;

+1 No way the FIA would not see it on the CAD data.
The idea of a heat switch in terms of a bimetal without airflow is also nonsense, as just a touching bimetal does not conduct significant heat.
Same goes for any air pressure changes, this does not change the heat conduction on realistic levels, if not good vacuum.

2. Is it actually possible that the brake ducts would have a significant impact in drag? I mean, in terms of frontal area, brake ducts are pretty much the same for every team. Also, brake ducts take air through a complex path for every car, regardless if they're the most advanced on the field or not, so it really doesn't make sense to me to think that a significant part of the straight line disadvantage of McLaren comes from these ducts;

Well, the question is rather what are teams doing with the brake ducts?
Over years the brake duct was not about cooling brakes or tires, this was more a side effect. Its main purpose for years was shaping flow and working as an aerodynamic device adding substantially to the downforce the car generates. Or as you point to drag: Reducing drag, aero efficiency.
Now let us think they changed their mind:

3. Last year there was already discussion of a magic solution from McLaren to improve tire cooling, the infamous "water on the tires" idea from Red Bull, and by that point there was no evidence of anything different on their brake ducts, so can we tell for sure if the brake ducts are the main factor for this advantage?;

I believe that focusing so much on one aspect of the car is a bit misleading. ......

Let us go back to double diffusors...everyone quickly learned how effective it is to use the diffusor. As a result of the double diffusor being forbidden, Newey invented the blown diffusor. As this was forbidden, the coanda was used...and so on...

Maybe it is exactly this story with the tire water:
I still do not think there is nothing behind. It was clear that people were experimenting with water, not blaming anyone for breaking rules...but they certainly learned how beneficial a bit more tire cooling is.

So, however McLaren learned it, they tried hard to find a different solution for tire cooling to replicate the benefit they knew and had the data to compromise on the aero part for it. And that goes into your whole car theory: They needed to change all aero, all flow shaping to reduce the effect of the brake ducts. Like this they could focus the brake duct more on tire cooling than on aero.

Would be interesting, if we can find hints on this theory on the floor and wings.

[SiLo]

I think tyre heat up isn't what we should be looking at, it's keeping the tyre cool over a longer distance. I don't think heat from a brake drum is going to have a big effect on overall tyre temperature over a single lap, but I could see how bulk temps can be kept down if the drum is just cooler overall. We have to remember that it takes time for heat transfer to happen, especially from the drum, which sits inside the wheel too.

[Tommy Cookers]

no-one is for shape-memory materials ?

phase-change ? - my favourite (around WT temperatures anyway) was Glauber's salt

well done those who said carbon composites can be made rather heat-conductive

[krisfx]

Newey invented the blown diffusor. As this was forbidden, the coanda was used...and so on...

Blown diffusers were around in the 80s...

[Hoffman900]

Newey invented the blown diffusor. As this was forbidden, the coanda was used...and so on...

Blown diffusers were around in the 80s...

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

[organic]

Newey invented the blown diffusor. As this was forbidden, the coanda was used...and so on...

Blown diffusers were around in the 80s...

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

In 20 years.. we'll hear marshall invented the rear brake duct

[AR3-GP]

A few points to consider:
1. In my interpretation a bimetallic strip would be considered a movable aerodynamic device and, therefore illegal, so I don't think that is it;

There is no wording of a "ban on movable aerodynamic devices" in the regulations. There are only bodywork classifications and prescriptions, in some cases, on the amount of flexibility that these parts may exhibit. Nothing is 100% rigid. If one would make use of two materials with differing thermal expansion coefficients, then the difference in expansion coefficients could open a small passageway allowing high pressure air to bleed through where not previously possible.

As I reviewed the regulations (https://www.fia.com/regulation/category/110), there are also no explicit deflection test in the internal cooling ducts of the wheel bodywork (3.13, 3.15). There is also nothing forbidding the use of multiple materials within the internal brake duct passages. So there are many ways to conceive of altered passageways owing to flexibility, or the phenomena of differing thermal expansion coefficients. That could trigger new flow pathways or even just some stall somewhere within the ducts.

We have not been able to physically examine the brake ducts of any team, but speculating is interesting.

[ispano6]

Any substance other than air will have weight, which will negatively affect the unsprung masses and the overall weight of the chassis. It will also contribute to the formation of condensation, which will flow through all possible cracks. In addition, such a thing will be very difficult to hide.

They use dry ice blowers to cool the brakes and that shouldn't have any mass right? It's just super cooled air. You just need to get it cooled and then seal it. Kind of like dumping the boiling water after it's been heated up, you don't need the water once it's up to temp. Likely it's not so simple and there is more going on than a Dewar flask or thermos, but no doubt clever and low on disadvantages. maybe there is some tradeoff in some way they are willing to accept.

[kptaylor]

Or a combo of both ideas. Bi-metalic strips to seal off the tire cooling until they're up to temp. Closing it off so little to no cooling happens, which heats up the rears quickly. Then at a specific temp the strip opens up to a cooling source ( super cooling?) that maintains the desired temp.

[SiLo]

Newey invented the blown diffusor. As this was forbidden, the coanda was used...and so on...

Blown diffusers were around in the 80s...

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

For the knowledge of others, it's Jean-Claude Migeot.

[Hoffman900]

I haven’t seen anyone throw some numbers around. Brakes are seeing temperatures in excess of 1000* C. How is what anyone hypothesizing works with that?

Furthermore, brake ducts have rules restricting the deflector and the drums themselves. Furthermore, blown axles are also banned. All this is related to controlling outwash.

Fit what you’re proposing within the rules and the operating parameters.

[tinuva]

Indeed, in heating up the tyres the McLaren doesn't really stand out. It's the "thermostat" function of keeping the tyres on the ideal temperature while pushing 100% is phenominal compared to all competitors. Really impressive stuff. Especially as the difference is huge and rear tyre overheating problems have been a part of F1 since the Pirelli tyres. So teams had this problem for ages and to have this big an advantage is in the region of Mercedes dominance and RB18/19. Like all here I'd be very interested to know what this game changer is

This is how I understood the video from the first post in this thread.

Phase-Changing Materials (PCM):

• The creator of the youtube video mentions having written a thesis at McLaren about these materials

• PCMs absorb large amounts of energy when changing state (solid to liquid)

• They maintain constant temperature during phase change

• Could be incorporated into drum covers to maintain optimal temperature

• The amount and type of material can be adjusted to absorb specific heat quantities

Trying to understand how this is against the rules, I don't see it. The idea is next level though.

[Alexf1]

Indeed, in heating up the tyres the McLaren doesn't really stand out. It's the "thermostat" function of keeping the tyres on the ideal temperature while pushing 100% is phenominal compared to all competitors. Really impressive stuff. Especially as the difference is huge and rear tyre overheating problems have been a part of F1 since the Pirelli tyres. So teams had this problem for ages and to have this big an advantage is in the region of Mercedes dominance and RB18/19. Like all here I'd be very interested to know what this game changer is

This is how I understood the video from the first post in this thread.

Phase-Changing Materials (PCM):

• The creator of the youtube video mentions having written a thesis at McLaren about these materials

• PCMs absorb large amounts of energy when changing state (solid to liquid)

• They maintain constant temperature during phase change

• Could be incorporated into drum covers to maintain optimal temperature

• The amount and type of material can be adjusted to absorb specific heat quantities

Trying to understand how this is against the rules, I don't see it. The idea is next level though.

Maybe Horner hinted at it by saying this kind of cooling power is not possible using only air. If the PCM is liquid at some point during time it could be illegal as it would be indirect liquid rim/tyre cooling.

[Farnborough]

In looking at these effects it's often productive to go with a "phase change " (pun intended ) in the thinking you approach them with.

Another way of "removing" heat from rear brakes could be to run effectively too high on regeneration in braking the rear axle, to then push excess capacity (keeping within the recovery remit) to resistance energy to heat exchange facility, then to cool that output through cooling capacity.

That would relocate the kinetic output to a more manageable location and allow liquid cooling of that as product.

Back down of regeneration potential in BBW system for Q laps (they do anyway, switching regeneration off for that single lap) would effectively move the heat "location" around the car to best effect.

Run race with higher regeneration in place while bleeding off excess through resistance/cooling exchange and away from rims.

It will give "differential" braking on rear axle too (rear retard operating through "open" diff setting) on corner entry, requiring different driver approach to that phase !!! a characteristic we've seen and commented about by both drivers.