Mercedes W13

[izzy]

I was wondering when we might see a low downforce rear wing. I wonder if that would actually reduce porpoising?

Yes, it's been said hasn't it, that they can get rid of the porpoising any time, by raising the ride height, and same issue with the rear wing: that they need the downforce. But the rear wing is more linear in its effect so I think that has to follow more than lead, if you see what I mean.

But by now they ought to have seen how the others have stopped the porpoising, so it depends how that is, what they have to do.

[Shakeman]

I don't know, the shape just seems so suboptimal aero wise.

It could also be that the shape produces unwieldy amounts of peak downforce that they simply cannot control without raising the ride height.

I'd love to know the level of downforce increases with the reduction in ride height and what the shape of the graph looks like. I'm sure someone could put some real numbers too it.

You mean those chunky rectangular cooling exit shapes behind the airbox that Merc, McLaren and Williams have, could be making lots of downforce?

Hmm I don't know, I can't fathom it.

They just seem so ungainly it's making me wonder if they just have cooling issues overall on the merc engine.

I know it's a consequence of experimental placement of cooling arrangements and such, but my hair won't allow me to believe the cars are actually purposely designed to look so boxy at the back.

No, I was thinking that Mercs zeropods and down wash mirror wings are combining to produce amazing airflow over the diffuser and making the under floor really 'peaky' in performance as the ride height lowers. Looking at the ground effect graph @just_a_fan posted, what if Merc's solution produces a curve that is both higher but a tighter peak than others which means the setup is virtually impossible and can be easily caused to stall by running over bumps because the peak downforce is so strong that no suspension can support it.

It seems to me you want to trade absolute peak downforce for a much broader curve that provides a higher average downforce over a broader ride height range.

I wonder if they've been surprised by just how much DF they've been generating that no suspension that operates like suspension can manage the load they're generating at low ride heights?

[AR3-GP]

It could also be that the shape produces unwieldy amounts of peak downforce that they simply cannot control without raising the ride height.

I'd love to know the level of downforce increases with the reduction in ride height and what the shape of the graph looks like. I'm sure someone could put some real numbers too it.

You mean those chunky rectangular cooling exit shapes behind the airbox that Merc, McLaren and Williams have, could be making lots of downforce?

Hmm I don't know, I can't fathom it.

They just seem so ungainly it's making me wonder if they just have cooling issues overall on the merc engine.

I know it's a consequence of experimental placement of cooling arrangements and such, but my hair won't allow me to believe the cars are actually purposely designed to look so boxy at the back.

No, I was thinking that Mercs zeropods and down wash mirror wings are combining to produce amazing airflow over the diffuser and making the under floor really 'peaky' in performance as the ride height lowers. Looking at the ground effect graph @just_a_fan posted, what if Merc's solution produces a curve that is both higher but a tighter peak than others which means the setup is virtually impossible and can be easily caused to stall by running over bumps because the peak downforce is so strong that no suspension can support it.

It seems to me you want to trade absolute peak downforce for a much broader curve that provides a higher average downforce over a broader ride height range.

I wonder if they've been surprised by just how much DF they've been generating that no suspension that operates like suspension can manage the load they're generating at low ride heights?

These are all certainly factors. I would add that tire stiffness cannot be controlled which may limit what they can do.

[dans79]

If you ignore the quotes thrown in at random, this is a pretty good overview of the issues.

[atanatizante]

Some car rake comparison between W13, F1-75 and RB 18 in order to see how much downforce they lose (yeah, it`s not the same magnification but you`ll get the point) ... this could explain why Toto said they had the draggiest car and in addition maybe they put some more rear wing just to compensate for the lack of downforce ...

[Shrieker]

Some car rake comparison between W13, F1-75 and RB 18 in order to see how much downforce they lose (yeah, it`s not the same magnification but you`ll get the point) ...

http://postimg.cc/XrY1dYkp
http://postimg.cc/3dJzC1K8

Ye it looks quite big. So they hit the rear of the floor quite a bit as well then.

And one more thing. Not only the rear, but the front is higher as well, although it's much more readily apparent at the rear.

[Mchamilton]

Some car rake comparison between W13, F1-75 and RB 18 in order to see how much downforce they lose (yeah, it`s not the same magnification but you`ll get the point) ...

http://postimg.cc/XrY1dYkp
http://postimg.cc/3dJzC1K8

Ye it looks quite big. So they hit the rear of the floor quite a bit as well then.

And one more thing. Not only the rear, but the front is higher as well, although it's much more readily apparent at the rear.

I believe mercedes said their temporary 'remedy' was to lift the front ride height

[dans79]

Some car rake comparison between W13, F1-75 and RB 18 in order to see how much downforce they lose (yeah, it`s not the same magnification but you`ll get the point) ...

http://postimg.cc/XrY1dYkp
http://postimg.cc/3dJzC1K8

Ye it looks quite big. So they hit the rear of the floor quite a bit as well then.

And one more thing. Not only the rear, but the front is higher as well, although it's much more readily apparent at the rear.

I believe mercedes said their temporary 'remedy' was to lift the front ride height

they raised the entire car, as can be seen when comparing testing to race weekend photos and videos. The might have raised the front more though.

Raising the ride height explains literally all the issues they had during the weekend.

[Big Tea]

You mean those chunky rectangular cooling exit shapes behind the airbox that Merc, McLaren and Williams have, could be making lots of downforce?

Hmm I don't know, I can't fathom it.

They just seem so ungainly it's making me wonder if they just have cooling issues overall on the merc engine.

I know it's a consequence of experimental placement of cooling arrangements and such, but my hair won't allow me to believe the cars are actually purposely designed to look so boxy at the back.

No, I was thinking that Mercs zeropods and down wash mirror wings are combining to produce amazing airflow over the diffuser and making the under floor really 'peaky' in performance as the ride height lowers. Looking at the ground effect graph @just_a_fan posted, what if Merc's solution produces a curve that is both higher but a tighter peak than others which means the setup is virtually impossible and can be easily caused to stall by running over bumps because the peak downforce is so strong that no suspension can support it.

It seems to me you want to trade absolute peak downforce for a much broader curve that provides a higher average downforce over a broader ride height range.

I wonder if they've been surprised by just how much DF they've been generating that no suspension that operates like suspension can manage the load they're generating at low ride heights?

These are all certainly factors. I would add that tire stiffness cannot be controlled which may limit what they can do.

Tyre stiff can be controlled, by pressure. It also affects ride height and 'turnability'

They are not allowed to run outside quite tight parameters tough, so prob not much help

[AR3-GP]

No, I was thinking that Mercs zeropods and down wash mirror wings are combining to produce amazing airflow over the diffuser and making the under floor really 'peaky' in performance as the ride height lowers. Looking at the ground effect graph @just_a_fan posted, what if Merc's solution produces a curve that is both higher but a tighter peak than others which means the setup is virtually impossible and can be easily caused to stall by running over bumps because the peak downforce is so strong that no suspension can support it.

It seems to me you want to trade absolute peak downforce for a much broader curve that provides a higher average downforce over a broader ride height range.

I wonder if they've been surprised by just how much DF they've been generating that no suspension that operates like suspension can manage the load they're generating at low ride heights?

These are all certainly factors. I would add that tire stiffness cannot be controlled which may limit what they can do.

Tyre stiff can be controlled, by pressure. It also affects ride height and 'turnability'

They are not allowed to run outside quite tight parameters tough, so prob not much help

Realistically Mercedes will just run at the minimums to increase mechanical grip and reduce sliding in the slow speed corners. So effectively they don't have free range to "increase tire pressure" until the tire no long deflects because it comes at the great expense of mechanical grip (or rather optimization of the tire contact patch) and even more loss of grip over small bumps.

So the tire does present an obstacle for the corner stiffness they desire. You can run a locked pushrod, and you will still have deflection on the tire.

[AR3-GP]

Some car rake comparison between W13, F1-75 and RB 18 in order to see how much downforce they lose (yeah, it`s not the same magnification but you`ll get the point) ... this could explain why Toto said they had the draggiest car and in addition maybe they put some more rear wing just to compensate for the lack of downforce ...

http://postimg.cc/XrY1dYkp
http://postimg.cc/3dJzC1K8

What part of the corner is this? It looks like the Mercedes has missed the apex so may have some brake application still.

[dans79]

Some car rake comparison between W13, F1-75 and RB 18 in order to see how much downforce they lose (yeah, it`s not the same magnification but you`ll get the point) ... this could explain why Toto said they had the draggiest car and in addition maybe they put some more rear wing just to compensate for the lack of downforce ...

http://postimg.cc/XrY1dYkp
http://postimg.cc/3dJzC1K8

What part of the corner is this? It looks like the Mercedes has missed the apex so may have some brake application still.

Looks like turn one, and since the screenshots says lap 12 that's literally the first turn lewis took on his out lap on the hards.

[Vanja #66]

Here's a graph for a generic ground effect device showing how the downforce (-Cl) varies with distance from the ground (ride height represented by the dimensionless relationship h/L because it's not just the distance from the ground but also the size of the device (the floor in this case) that determines ground effect - a large body will be "in ground effect" at a greater height than a small body).

https://www.researchgate.net/profile/Jo ... l-with.png

You can see how the downforce changes a lot with a small change in ride height near the peak.

This is obviously a simplified device but it shows the effect.

Somehow, we always come back to prof. Katz's basic diagrams. I'd just like to add a wing in ground effect diagram as well.



The two are very similar clearly. However, relative clearance ratios are a bit different, wing requires 2-3x more relative clearance. These 2022 floors are shaped more like the bottom of the wing, but there are also similarities to classical diffuser shape. I haven't seen diffuser-like vortices alongside ramp fences in flow-viz shots, so I suspect the flow is a lot closer to a wing than a diffuser. Ideally, I think teams want to have a long low zone to avoid peaks, something like inverted supercritical foil on the picture, as peaky geometry could hurt a lot in some pitch and roll attitudes.

[siskue2005]

Speed at the start finish line
great info

[dans79]

Speed at the start finish line
great info
https://serving.photos.photobox.com/846 ... 8a5e7a.jpg

So The merc was as fast or faster than all the other top 3 teams. Kind of lends support to the belife thats they messed with the mappings and wing settings to compensate for the increased ride height!