2023 car comparison thread

[ing.]

I have a theory that the venturis under the RBR have a more rearward COP and have bigger volume underneath. Posted in w14 thread. And i think this is why they can ride lower.

I said the same last year. RB have (had) higher, more rounded ceiling of the underfloor making it less sensitive to volume change vs. ground clearance and probably allowing more room for the vortices generated by the strakes to remain intact as the ground clearance is reduced. A lot of literature by Katz about this latter phenomenon.

[vorticism]

I said the same last year. RB have (had) higher, more rounded ceiling of the underfloor making it less sensitive to volume change vs. ground clearance and probably allowing more room for the vortices generated by the strakes to remain intact as the ground clearance is reduced. A lot of literature by Katz about this latter phenomenon.

Let's have a look at how Newey was designing diffusers 35 years ago...

[Vanja #66]

I have a theory that the venturis under the RBR have a more rearward COP and have bigger volume underneath. Posted in w14 thread. And i think this is why they can ride lower.

It's not really a theory, it's a well discussed fact during last year. The profile of RB18 and now AMR23 (by the looks of it) provides a small and powerful low-pressure zone in the rear and somewhat limits the potential for more downforce on its own. The profile, not the floor. One of the reasons Ferrari had more floor downforce than RB18 until TD39 kicked in and the car was raised forcibly.

***


This is very far from what typical ground effect floor pressure distribution looks like and the rear end is practically the same as previous generation diffuser floors. You can be sure that other teams, with conventional ground effect floor design, have a very, very different pressure distribution, far more even as opposed to RB peaky downforce design.

The one thing that became clearer now with more pictures is that there is actually a (very) short surface of the throat, but it did look like an edge last year. Doesn't change the philosophy, just the pressure distribution a bit...

[vorticism]

https://i.ibb.co/2dWCbvp/iBwWx4U.jpg
***
https://i.ibb.co/44dsV89/rb-floor.jpg

Add one more to your "You should do CFD of this" yelled from the crowd list: RB18 close coupled bargeboards.

[Vanja #66]

That list is starting to get very long and my schedule is getting very short...

[ringo]

I will do some. I just need the time to model.
Just too busy.
Also i dont like how these new regs are written. Too confusing.
What I will do is just freehand a floor that will not be to any scale geometry of the regs, but it will demonstrate comparisons.

[ringo]

I have a theory that the venturis under the RBR have a more rearward COP and have bigger volume underneath. Posted in w14 thread. And i think this is why they can ride lower.

It's not really a theory, it's a well discussed fact during last year. The profile of RB18 and now AMR23 (by the looks of it) provides a small and powerful low-pressure zone in the rear and somewhat limits the potential for more downforce on its own. The profile, not the floor. One of the reasons Ferrari had more floor downforce than RB18 until TD39 kicked in and the car was raised forcibly.

https://i.ibb.co/2dWCbvp/iBwWx4U.jpg
***
https://i.ibb.co/44dsV89/rb-floor.jpg

This is very far from what typical ground effect floor pressure distribution looks like and the rear end is practically the same as previous generation diffuser floors. You can be sure that other teams, with conventional ground effect floor design, have a very, very different pressure distribution, far more even as opposed to RB peaky downforce design.

The one thing that became clearer now with more pictures is that there is actually a (very) short surface of the throat, but it did look like an edge last year. Doesn't change the philosophy, just the pressure distribution a bit...

It's the most important feature of the floors. I do not think it's trivial.
And that's why mercedes missed the trick. Doing a steady state or single capture will conclude one has a certain distribution so its gonna have more downforce. But for a distribution of heights how often will this be the case?
And I disagree that it's well discussed.

[AR3-GP]

I have a theory that the venturis under the RBR have a more rearward COP and have bigger volume underneath. Posted in w14 thread. And i think this is why they can ride lower.

It's not really a theory, it's a well discussed fact during last year. The profile of RB18 and now AMR23 (by the looks of it) provides a small and powerful low-pressure zone in the rear and somewhat limits the potential for more downforce on its own. The profile, not the floor. One of the reasons Ferrari had more floor downforce than RB18 until TD39 kicked in and the car was raised forcibly.

https://i.ibb.co/2dWCbvp/iBwWx4U.jpg
***
https://i.ibb.co/44dsV89/rb-floor.jpg

This is very far from what typical ground effect floor pressure distribution looks like and the rear end is practically the same as previous generation diffuser floors. You can be sure that other teams, with conventional ground effect floor design, have a very, very different pressure distribution, far more even as opposed to RB peaky downforce design.

The one thing that became clearer now with more pictures is that there is actually a (very) short surface of the throat, but it did look like an edge last year. Doesn't change the philosophy, just the pressure distribution a bit...

It's the most important feature of the floors. I do not think it's trivial.
And that's why mercedes missed the trick. Doing a steady state or single capture will conclude one has a certain distribution so its gonna have more downforce. But for a distribution of heights how often will this be the case?
And I disagree that it's well discussed.

The teams test ride height variation in their CFD and windtunnel so it shouldn't be something that they missed.

[ringo]

I think mercedes did allude to the possibility of being limited in transient analysis. I cannot find the quote. But I am sure they will be looking at their tools. They havent updated their tools in a while i hear. I do not know hoe true this is.
But it's obvious when you see one team have a narrow window of operation and the other doesnt it simply means more analysis was done by the other team.
There are surprises in engineering when: there is lack of awareness, the assumptions made were wrong, or when what is considered negligible is not negligible in reality.
I Would like to see the F175 floor from 2022 and compare to the RB18. If the the same signs are there then there is some indication that some of the performance differences lie in the tunnel profile.

[AR3-GP]

I think mercedes did allude to the possibility of being limited in transient analysis. I cannot find the quote.

Absolutely but this applies to all teams. A windtunnel model motion system moves fairly slowly but this applies to all F1 teams. The windtunnel cannot simulate the fast pitch and yaw rates that are encountered in the real world.

[Vanja #66]

So, rear wings don't flex any more?



Just as a reminder, camera is fixed on the chassis, so the suspension movement under braking is observed with rear tyre movement (also marked)

[Im_W1ll]

So, rear wings don't flex any more?

https://i.ibb.co/hfrjXQ7/jeddah-2023-williams-flex.jpg

Just as a reminder, camera is fixed on the chassis, so the suspension movement under braking is observed with rear tyre movement (also marked)

Is the whole rear wing moving of just the trailing edge? They could have purposefully built a weak point to let the angle of attack of the rear wing change under aerodynamic load... Feel free to correct me, I'm still a high school student in a big world.

Great find , really interesting to see.

[Cs98]

So, rear wings don't flex any more?

https://i.ibb.co/hfrjXQ7/jeddah-2023-williams-flex.jpg

Just as a reminder, camera is fixed on the chassis, so the suspension movement under braking is observed with rear tyre movement (also marked)

The new Merc rear wing flexes quite noticeably. Definitely part of their lower drag philosophy.

[Farnborough]

I have a theory that the venturis under the RBR have a more rearward COP and have bigger volume underneath. Posted in w14 thread. And i think this is why they can ride lower.

It's not really a theory, it's a well discussed fact during last year. The profile of RB18 and now AMR23 (by the looks of it) provides a small and powerful low-pressure zone in the rear and somewhat limits the potential for more downforce on its own. The profile, not the floor. One of the reasons Ferrari had more floor downforce than RB18 until TD39 kicked in and the car was raised forcibly.

https://i.ibb.co/2dWCbvp/iBwWx4U.jpg
***
https://i.ibb.co/44dsV89/rb-floor.jpg

This is very far from what typical ground effect floor pressure distribution looks like and the rear end is practically the same as previous generation diffuser floors. You can be sure that other teams, with conventional ground effect floor design, have a very, very different pressure distribution, far more even as opposed to RB peaky downforce design.

The one thing that became clearer now with more pictures is that there is actually a (very) short surface of the throat, but it did look like an edge last year. Doesn't change the philosophy, just the pressure distribution a bit...

A question about graphic, the part marked as "peak downforce" and illustrated by the blue zone, is thst not peak vacuum in venturi position with downforce being enacted by the roof of the tunnel upstream of that location ?

Doesn't the vacuum need surface area to impose load (negative) on the structure rather than that narrow band ?

Thank you.

[AR3-GP]

So, rear wings don't flex any more?

https://i.ibb.co/hfrjXQ7/jeddah-2023-williams-flex.jpg

Just as a reminder, camera is fixed on the chassis, so the suspension movement under braking is observed with rear tyre movement (also marked)

The amount of movement here is small imo.