Mercedes W15

[GrizzleBoy]

Ever since I saw their floor in 2022 it has always looked well underdeveloped on its underside and it still seems to be the case in 2024.

Hopefully they just gave up on developing the floor too much till they completed the top of the car so they could make a new floor around it.

Otherwise they seem like they just don't know what to do.

One thing to remember is that teams like McLaren and Aston faced periods of turmoil after starting their RB18/19 clone journeys before they became somewhat competitive again.

[michl420]

Did anyone notice the vibration on one of the small winglets around the barge board area on the rear facing TV feed? It was moving quite significantly horizontally and made me wonder if that could be causing some issues.

I see it one the main "bargeboard" , the outside van of the floor strakes. On HAM car it even crake and bend backwards 2 laps before finish in the jeddah gp.

[ringo]

There's a curious detail on that floor and it's visible on both photos and looks the same, so it's not a reflection/glitch of a photo. It looks like an indent in the floor roof, spanning across entire tunnel width. Not sure what it is supposed to do, if it really is a local increase in tunnel roof height.

https://i.ibb.co/VYPMHD0/8fouw58sx7qc1.png

Seems to be more like the illusion of the convex shape of the floor and the ramp down from the floor entry.

[ringo]

What I do notice about this W15 is the turning vanes on either side of the entry to the floor is a flat plate.
Redbull, and Mclaren have a dog eared or bent lower tip turning towards the mouth of the floor. This could be a vortex generator that reduces floor sensitivity.

Flat plate.



red bull and mclaren with a more curved plate and bent in tip.

There are more differences between the floors that could explain W15's issues. And it may be a lot of little things.

Switching gears a bit from the previous observation.

The rear suspension is also very peculiar relative to the diffuser geometry, but I don't have much to say on that for now. But noticed a difference with this car. The pick-up point location would suggest much different motion center to the Mclaren and the Redbull. The latter cars have the control arms points closer to or even upstream the diffuser throat.
The floor movement or rotation relative to rear suspension travel could be less compared to W15.

[kimble]

Did anyone notice the vibration on one of the small winglets around the barge board area on the rear facing TV feed? It was moving quite significantly horizontally and made me wonder if that could be causing some issues.

I see it one the main "bargeboard" , the outside van of the floor strakes. On HAM car it even crake and bend backwards 2 laps before finish in the jeddah gp.

I've been trying to find a video of it but have failed, if you have one please post it. I can't believe the team haven't noticed but if that's happening in high speed corners then it must be having a negative impact.

[atanatizante]

In the Australia race debrief Allison said the W15 car loses performance once the temperature rises in qualy and the races.

There could be at least 2 reasons for that thing occurring:

1. Pressure inside the tyres is rising hence ride height increases leading to a lower downforce level from the floor
2. Nowing that the Venturi effect can be used to measure the volumetric flow rate, with the temperature rising the air density would lower thus the volume inside the tunnels is smaller hence downforce lowers ...

This year W15 is one of the few cars that is running very low hence why they are often sparking on the straight.
This could backfire them had they would find that air density is a very sensible parameter in downforce generating for their car.

In contrast, RB20 car and other top cars are running much higher and this could lead to at least 2 things:

- firstly, those cars have more developed/advanced floors + diffusers that generate much higher downforce levels than W15 (as we could figure out seeing RUS` car floor), which could afford them to run much higher ride heights or

- secondly, they have a downforce limiter/staller switch more evolved, benefiting from the advanced knowledge that the old guys Newey and Rory Byrne on the ground effect cars have ...

[Venturiation]

In the Australia race debrief Allison said the W15 car loses performance once the temperature rises in qualy and the races.

There could be at least 2 reasons for that thing occurring:

1. Pressure inside the tyres is rising hence ride height increases leading to a lower downforce level from the floor
2. Nowing that the Venturi effect can be used to measure the volumetric flow rate, with the temperature rising the air density would rise thus the volume inside the tunnels is smaller hence downforce lowers ...

This year W15 is one of the few cars that is running very low hence why they are often sparking on the straight.
This could backfire them had they would find that air density is a very sensible parameter in downforce generating for their car.

In contrast, RB20 car and other top cars are running much higher and this could lead to at least 2 things:

- firstly, those cars have more developed/advanced floors + diffusers that generate much higher downforce levels than W15 (as we could figure out seeing RUS` car floor), which could afford them to run much higher ride heights or

- secondly, they have a downforce limiter/staller switch more evolved, benefiting from the advanced knowledge that the old guys Newey and Rory Byrne on the ground effect cars have ...

For 2 years the consensus was that redbull runs the car the lowest to the ground why are you saying they run higher

[j_ste]

In the Australia race debrief Allison said the W15 car loses performance once the temperature rises in qualy and the races.

There could be at least 2 reasons for that thing occurring:

1. Pressure inside the tyres is rising hence ride height increases leading to a lower downforce level from the floor
2. Nowing that the Venturi effect can be used to measure the volumetric flow rate, with the temperature rising the air density would rise thus the volume inside the tunnels is smaller hence downforce lowers ...

This year W15 is one of the few cars that is running very low hence why they are often sparking on the straight.
This could backfire them had they would find that air density is a very sensible parameter in downforce generating for their car.

In contrast, RB20 car and other top cars are running much higher and this could lead to at least 2 things:

- firstly, those cars have more developed/advanced floors + diffusers that generate much higher downforce levels than W15 (as we could figure out seeing RUS` car floor), which could afford them to run much higher ride heights or

- secondly, they have a downforce limiter/staller switch more evolved, benefiting from the advanced knowledge that the old guys Newey and Rory Byrne on the ground effect cars have ...

For 2 years the consensus was that redbull runs the car the lowest to the ground why are you saying they run higher

Was that the consensus? I thought the reason they were ok with the TD in 2022 was because they already ran their car higher and it wouldnt be an issue.

Where as eveeyone else needed to run it low to get desired results or hopefully results

[Venturiation]

In the Australia race debrief Allison said the W15 car loses performance once the temperature rises in qualy and the races.

There could be at least 2 reasons for that thing occurring:

1. Pressure inside the tyres is rising hence ride height increases leading to a lower downforce level from the floor
2. Nowing that the Venturi effect can be used to measure the volumetric flow rate, with the temperature rising the air density would rise thus the volume inside the tunnels is smaller hence downforce lowers ...

This year W15 is one of the few cars that is running very low hence why they are often sparking on the straight.
This could backfire them had they would find that air density is a very sensible parameter in downforce generating for their car.

In contrast, RB20 car and other top cars are running much higher and this could lead to at least 2 things:

- firstly, those cars have more developed/advanced floors + diffusers that generate much higher downforce levels than W15 (as we could figure out seeing RUS` car floor), which could afford them to run much higher ride heights or

- secondly, they have a downforce limiter/staller switch more evolved, benefiting from the advanced knowledge that the old guys Newey and Rory Byrne on the ground effect cars have ...

For 2 years the consensus was that redbull runs the car the lowest to the ground why are you saying they run higher

Was that the consensus? I thought the reason they were ok with the TD in 2022 was because they already ran their car higher and it wouldnt be an issue.

Where as eveeyone else needed to run it low to get desired results or hopefully results

TD was about the floor edge and ride height if you were bouncing, Redbull wasn't bouncing so they keep as low as they want

[ringo]

The redbull does seem to run the lowest. Or should I say spend the most time of the lap at a very low ride.
The temperature factor is an interesting one and not surprising. The car being this senstive is definitely pointing to the fundamental understanding of the physics or even how the engineers are design the car.
What kind of tyre stiffness and diameter chanfe are we talking with a track temperature change?

[venkyhere]

2. Nowing that the Venturi effect can be used to measure the volumetric flow rate, with the temperature rising the air density would rise thus the volume inside the tunnels is smaller hence downforce lowers ...

This year W15 is one of the few cars that is running very low hence why they are often sparking on the straight.
This could backfire them had they would find that air density is a very sensible parameter in downforce generating for their car.

Isn't it the other way around ?
As ambient air temperature rises, the air density reduces, leading to lesser number of molecules to 'enter' the venturi at the same speed (in comparison to - same speed, same track, lower air temp occasion) and thus leading to a "weaker" throat effect on flow-pressure differential , and thus less effective downforce ?

Hotter air is less dense than cold air, otherwise hot-air-balloons wouldn't be a mode of travel.

[ringo]

I think what was of note was the track temperature and not much the ambient. Though if the ambient goes up the track temperature will.
The problem seems to be with the change in the tyres from increased temperature and hpw that impacts the aero.
There also seems to be the front to back change is not proportional and the balance als9 gets thrown off.

[Rodak]

2. Nowing that the Venturi effect can be used to measure the volumetric flow rate, with the temperature rising the air density would rise thus the volume inside the tunnels is smaller hence downforce lowers ...

This year W15 is one of the few cars that is running very low hence why they are often sparking on the straight.
This could backfire them had they would find that air density is a very sensible parameter in downforce generating for their car.

Isn't it the other way around ?
As ambient air temperature rises, the air density reduces, leading to lesser number of molecules to 'enter' the venturi at the same speed (in comparison to - same speed, same track, lower air temp occasion) and thus leading to a "weaker" throat effect on flow-pressure differential , and thus less effective downforce ?

Hotter air is less dense than cold air, otherwise hot-air-balloons wouldn't be a mode of travel.

Yeah, I was going to point this out too. What we're really looking at is mass flow, so less air density with increased temperature leads to a lower mass flow through the system. Think density altitude for aircraft.....

[atanatizante]

2. Nowing that the Venturi effect can be used to measure the volumetric flow rate, with the temperature rising the air density would rise thus the volume inside the tunnels is smaller hence downforce lowers ...

This year W15 is one of the few cars that is running very low hence why they are often sparking on the straight.
This could backfire them had they would find that air density is a very sensible parameter in downforce generating for their car.

Isn't it the other way around ?
As ambient air temperature rises, the air density reduces, leading to a lesser number of molecules 'entering' the venturi at the same speed (in comparison to - same speed, same track, lower air temp occasion) and thus leading to a "weaker" throat effect on the flow-pressure differential, and thus less effective downforce?

Hotter air is less dense than cold air, otherwise, hot-air balloons wouldn't be a mode of travel.

My bad! Of course, it`s a no-brainer that when the air is hotter the air molecules are lesser hence the air velocity is lower ... I was just focused on the density and volume relation which misleade me into this error ...

[atanatizante]

I think what was of note was the track temperature and not much the ambient. Though if the ambient goes up the track temperature will.
The problem seems to be with the change in the tyres from increased temperature and hpw that impacts the aero.
There also seems to be the front-to-back change is not proportional and the balance als9 gets thrown off.

From my point of view, another basic understanding is how they setup the suspension/damper system and ride height for qualy session, seeing that the car is running so low hence sparking on the straight, knowing that in the race they`ll have a car full of fuel and a rise of tyre temperature that induces a ride height rise hence another downforce loss ... or on another say of speaking how come they setup the car to run the lowest in qualy then the car isn`t bottoming in the race ... is just only the tyre temp rising doing the trick?