Red Bull RB18

[AR3-GP]

https://twitter.com/NaturalParadigm/sta ... VP3Dc4_9sg
Could this be the key to their no-porpoising success?

No. They don't bounce because they generate less downforce from floor, coming from slightly bigger tunnel height compared to Ferrari and Mercedes.

How come they were bouncing in Bahrain? Then they changed the sidepod and rear suspension and suddenly they are not bouncing.

Imo saying they aren't generating downforce from the floor is far too simpleton of an explanation and I think you know that...They are running smaller wings than Ferrari as well so there's no explanation for their medium and high speed cornering performance if they don't have floor downforce.

Imo they are not bouncing because of the suspension system which has been very refined. They introduced a suspension upgrade in Bahrain and from that moment, the car stopped bouncing.

[godlameroso]

https://twitter.com/NaturalParadigm/sta ... VP3Dc4_9sg
Could this be the key to their no-porpoising success?

No. They don't bounce because they generate less downforce from floor, coming from slightly bigger tunnel height compared to Ferrari and Mercedes.

How come they were bouncing in Bahrain? Then they changed the sidepod and rear suspension and suddenly they are not bouncing.

Imo saying they aren't generating downforce from the floor is far too simpleton of an explanation and I think you know that...They are running smaller wings than Ferrari as well so there's no explanation for their medium and high speed cornering performance if they don't have floor downforce.

Imo they are not bouncing because of the suspension system which has been very refined. They introduced a suspension upgrade in Bahrain and from that moment, the car stopped bouncing.

Not only that, the tunnels themselves are not the end all be all for downforce generation, a lot of it comes from the central section with the plank. That air is accelerated all the way from the strakes to the gearbox.

[carisi2k]

@AR3-GP The red bulls were not porpoising in Bahrain. Atleast not that anybody could actually tell on there car unlike the Merc and Ferrari.

One person put out a video claiming red bull were porpoising but it was just the bumps in the track at the end of the straight and the red bull riding those bumps and no actual porpoising was happening.

(

[Vanja #66]

How do you know how much downforce they generate from the floor? Didn't RBR say they controlled the bouncing with their suspension? If they made less downforce, how are they the fastest in high speed corners despite a smaller rear wing?

Because tunnel height is the biggest impact factor for floor downforce. We know this from aerodynamics books and I can also confirm from experience. The inlet/outlet ratio is second and the profile/shape is tertiary impact factor. Now, if you have higher tunnel, but you can have lower ride height, you basically get the best of both worlds and both of these apply to RB18.

Bouncing can be slightly minimized with clever suspension, but if you generate 200-300kg less downforce from floor at 320km/h (which is nothing at those speeds) than you can have a lot less problems. Not sure about RB being faster in high-speed corners so far, at best they were equal to Ferrari. Also, in Melbourne and Imola they had more rear wing than Ferrari and their rear wing is higher camber than Ferrari. Along with larger DRS flap, this is why they have a decent advantage with DRS overtaking.

Imo saying they aren't generating downforce from the floor is far too simpleton of an explanation and I think you know that...They are running smaller wings than Ferrari as well so there's no explanation for their medium and high speed cornering performance if they don't have floor downforce.

As mentioned above, higher camber of rear wing and also larger wing overall in Melbourne and Imola.

Not only that, the tunnels themselves are not the end all be all for downforce generation, a lot of it comes from the central section with the plank. That air is accelerated all the way from the strakes to the gearbox.

"Think logically." How can a flat geometry with no curvature and close to no AoA influence pressure distribution? Is it, in fact, low pressure from tunnels influencing and accelerating the air on the plank? Hint: yes

[ing.]

How do you know how much downforce they generate from the floor? Didn't RBR say they controlled the bouncing with their suspension? If they made less downforce, how are they the fastest in high speed corners despite a smaller rear wing?

Because tunnel height is the biggest impact factor for floor downforce. We know this from aerodynamics books and I can also confirm from experience. The inlet/outlet ratio is second and the profile/shape is tertiary impact factor. Now, if you have higher tunnel, but you can have lower ride height, you basically get the best of both worlds and both of these apply to RB18.

Bouncing can be slightly minimized with clever suspension, but if you generate 200-300kg less downforce from floor at 320km/h (which is nothing at those speeds) than you can have a lot less problems. Not sure about RB being faster in high-speed corners so far, at best they were equal to Ferrari. Also, in Melbourne and Imola they had more rear wing than Ferrari and their rear wing is higher camber than Ferrari. Along with larger DRS flap, this is why they have a decent advantage with DRS overtaking.

Imo saying they aren't generating downforce from the floor is far too simpleton of an explanation and I think you know that...They are running smaller wings than Ferrari as well so there's no explanation for their medium and high speed cornering performance if they don't have floor downforce.

As mentioned above, higher camber of rear wing and also larger wing overall in Melbourne and Imola.

Not only that, the tunnels themselves are not the end all be all for downforce generation, a lot of it comes from the central section with the plank. That air is accelerated all the way from the strakes to the gearbox.

"Think logically." How can a flat geometry with no curvature and close to no AoA influence pressure distribution? Is it, in fact, low pressure from tunnels influencing and accelerating the air on the plank? Hint: yes

+1

Current cars’ problems are aeroelasticity-related and they display two aeroelastic problems:

1/ Divergence: this is where the DF is increased as deflection—in this case it’s the car on suspension versus the wing structure on an airplane—is increased. This is an unstable situation.

2/ Flutter: uncontrolled vibration, and again in this case we’re taking the car body on the suspension as opposed to the wing structure on an aircraft.

In both cases an important factor is understanding the so-called aero derivatives—basically the change in aero loading per unit displacement of the aero surfaces, in this case either ride height, pitch, roll or maybe even the edges of the floor. From this, it is obvious that the height of the tunnel floors is a factor if these can be made less sensitive to ride height. Obviously, the ratio of inlet area to throat area should be optimized to get the best acceleration of area through the venturi.



So is RBR’s throat section taller but narrower than the others? Or, if the same width, is the relative inlet area larger?

[VacuousFlamboyant]

+1

Current cars’ problems are aeroelasticity-related and they display two aeroelastic problems:

1/ Divergence: this is where the DF is increased as deflection—in this case it’s the car on suspension versus the wing structure on an airplane—is increased. This is an unstable situation.

2/ Flutter: uncontrolled vibration, and again in this case we’re taking the car body on the suspension as opposed to the wing structure on an aircraft.

In both cases an important factor is understanding the so-called aero derivatives—basically the change in aero loading per unit displacement of the aero surfaces, in this case either ride height, pitch, roll or maybe even the edges of the floor. From this, it is obvious that the height of the tunnel floors is a factor if these can be made less sensitive to ride height. Obviously, the ratio of inlet area to throat area should be optimized to get the best acceleration of area through the venturi.

https://i.imgur.com/MDt0t1K.jpg

So is RBR’s throat section taller but narrower than the others? Or, if the same width, is the relative inlet area larger?

I get the impression the difference in volume in the cross section between them comes from the sides. Mercedes' floor ends sooner, that would explain the sealing requirements and overall design choice compared to RB. Like this:

[ing.]

How do you know how much downforce they generate from the floor? Didn't RBR say they controlled the bouncing with their suspension? If they made less downforce, how are they the fastest in high speed corners despite a smaller rear wing?

Because tunnel height is the biggest impact factor for floor downforce. We know this from aerodynamics books and I can also confirm from experience. The inlet/outlet ratio is second and the profile/shape is tertiary impact factor. Now, if you have higher tunnel, but you can have lower ride height, you basically get the best of both worlds and both of these apply to RB18.

Bouncing can be slightly minimized with clever suspension, but if you generate 200-300kg less downforce from floor at 320km/h (which is nothing at those speeds) than you can have a lot less problems. Not sure about RB being faster in high-speed corners so far, at best they were equal to Ferrari. Also, in Melbourne and Imola they had more rear wing than Ferrari and their rear wing is higher camber than Ferrari. Along with larger DRS flap, this is why they have a decent advantage with DRS overtaking.

Imo saying they aren't generating downforce from the floor is far too simpleton of an explanation and I think you know that...They are running smaller wings than Ferrari as well so there's no explanation for their medium and high speed cornering performance if they don't have floor downforce.

As mentioned above, higher camber of rear wing and also larger wing overall in Melbourne and Imola.

Not only that, the tunnels themselves are not the end all be all for downforce generation, a lot of it comes from the central section with the plank. That air is accelerated all the way from the strakes to the gearbox.

"Think logically." How can a flat geometry with no curvature and close to no AoA influence pressure distribution? Is it, in fact, low pressure from tunnels influencing and accelerating the air on the plank? Hint: yes

-5

The tunnels are not the biggest source of acceleration, the jet that comes from the central section is much faster therefore the pressure there is much lower.

The plank area isn't flat, only the piece of wood is flat, the plank doesn't take up all of the central section, and the central section is closer to the floor than either tunnel.

https://c8.alamy.com/comp/2J5CEYR/imola ... J5CEYR.jpg

https://c8.alamy.com/comp/2J5KGMP/imola ... J5KGMP.jpg

The plank area is closer to the ground, you can see it in these two images. Furthermore the central section ends at the transmission and gently curves upward, so you're just wrong, flat out wrong.

https://www.motorsportweek.com/wp-conte ... Custom.jpg

No curvature here at the trailing edge of the central section, don't believe your lying eyes.

https://files.catbox.moe/mizi5k.jpg That's not a curve everyone, that's a straight line, don't believe your lying eyes. The ministry of truth has spoken.

Center section for sure contributes DF but, as you pointed out, the relatively limited diffusion at the rear—either by necessity for gearbox or by aero—points to the fact that there is little additional speed or energy in this area.

This is like when Ferrari in ‘85 was running a full width diffuser because of their transverse gearbox and all the other teams were concerned until they realized that the flow in the diffuser at the center was most likely stalled due to the loss of energy of the flow along the full length on the chassis at the center.

[Vanja #66]

https://i.imgur.com/MDt0t1K.jpg

So is RBR’s throat section taller but narrower than the others? Or, if the same width, is the relative inlet area larger?

Good questions. I think RB18 has taller, but not narrower floor section. Not only throat section, but the entire low zone. They have double curvature surfaces all over the floor and it's not easy to distinguish every detail from limited photos we have access to.

As you illustrated, their tunnels are clearly higher compared to Mercedes. Ferrari is somwhere in between.

[zioture]

[AR3-GP]

I suspect that the skate is another red herring as it regards to "anti-porpoising'. Ferrari have been running a similar device and they still bounce. It's just that this ice skate is conceptually easy for the layman to point to whereas aerodynamics of an F1 car is rarely simple.

[AR3-GP]

Upgrade watch?

[djones]

Given the skate hits the floor....

How is the skate not classed as a skirt and breaking the rules?

[matteosc]

Given the skate hits the floor....

How is the skate not classed as a skirt and breaking the rules?

I guess that since it has holes, it does not create a "sealing".

[SmallSoldier]

Side view of the RB18 “skates”:



Vía: NicolasF1i

[AR3-GP]

Given the skate hits the floor....

How is the skate not classed as a skirt and breaking the rules?

It's not a skirt. It's an edge wing and it satisfies the floor edge wing regulation. Whether it hits the floor or not is inconsequential.