Red Bull RB18

[diffuser]

"Rake" as I understand it, is using suspention to elevate the entire back of a flat floor design rule to have said flat floor work as a diffuser, getting some downforce with low drag. It is a workaround to a rule and not a design goal. It made flat floor cars pointy, because it lowered the front wing in a car rule in which a lower wing was better.

As the flat floor is no longer there and most of the floor is now intricately designed, rake is not really relevant is it? It could only apply to the plank area. And even then, would the floor edge be a means of judging any rake of the plank? Im not familiar with the exact rules on the floor edge positioning relative to the plank, but maybe they are not in the same plane at all.

That's what I tried to say the other day, not as eloquently, but I tried.

You couldn't touch the floor back then, while today, there is all kind of space that they can play with in there, from a rule perspective.

Also, raising the floor drops the nose and front wing. At the very least that gonna create turbulence to some of the air feeding into the floor, worst case reduction of the air available to the floor. Wing regs are such that make it very difficult to do much more that create df at the wing.

[ringo]

You cannot say rake is not relevant. No technical or evidential grounds to say that at all.
The whole point of having rake in the car is the increase the effective volume of the diffuser, and thus the expansion ratio. If the floor design is not understood, then that's even more reason to not draw conclusions on what is relevant or not. The rake will give the car more downforce, even for a tunnel car. At very high speeds, such as on the straight, all the downforce may not be needed so we have seen trick suspensions where the rear comes down. That still holds with the tunnel cars, maybe its more tricky to control, who knows, but not seeing why the principle would not apply to both philosophies.

[Edax]

https://i.imgur.com/HTo0gn7.jpg

The rake discussion is interesting, but the fact that in the above image redbull have increased the area of the tunnel intakes, we can probably assume that their understanding of the flows, in simulation and reality, are well understood and they have now decided to add some rake to benefit the lower speed corner performance The added volume of air in the central section(s) is just an optimization of their design.

This may also prove to be the reason why the "hole" in the diffuser has also grown (image below), in order to bleed of the added volume of air in the tunnels and prevent bouncing/porpoising at high speeds:

https://cdn-1.motorsport.com/images/mgl ... loor-1.jpg

Still think you need to find more pictures of rake than the one of the car exiting the garage. Which, for all we know, might have just been raised in the rear to test something. We have no evidence that this didn't drop back down to regular high after it travel 1cm after this picture was taken. Even your picture of the new larger diffuser openning has no rake.

Maybe this picture from Montreal helps.

https://www.redbullracing.com/int-en/ga ... grand-prix

[diffuser]

You cannot say rake is not relevant. No technical or evidential grounds to say that at all.
The whole point of having rake in the car is the increase the effective volume of the diffuser, and thus the expansion ratio. If the floor design is not understood, then that's even more reason to not draw conclusions on what is relevant or not. The rake will give the car more downforce, even for a tunnel car. At very high speeds, such as on the straight, all the downforce may not be needed so we have seen trick suspensions where the rear comes down. That still holds with the tunnel cars, maybe its more tricky to control, who knows, but not seeing why the principle would not apply to both philosophies.

I'm not an expert, just an arm chair F1 fan. I'm not saying it isn't possible. I'm just saying that it doesn't make sense to me and I'm interested in talking about it.

[diffuser]

https://i.imgur.com/HTo0gn7.jpg

The rake discussion is interesting, but the fact that in the above image redbull have increased the area of the tunnel intakes, we can probably assume that their understanding of the flows, in simulation and reality, are well understood and they have now decided to add some rake to benefit the lower speed corner performance The added volume of air in the central section(s) is just an optimization of their design.

This may also prove to be the reason why the "hole" in the diffuser has also grown (image below), in order to bleed of the added volume of air in the tunnels and prevent bouncing/porpoising at high speeds:

https://cdn-1.motorsport.com/images/mgl ... loor-1.jpg

Still think you need to find more pictures of rake than the one of the car exiting the garage. Which, for all we know, might have just been raised in the rear to test something. We have no evidence that this didn't drop back down to regular high after it travel 1cm after this picture was taken. Even your picture of the new larger diffuser openning has no rake.

Maybe this picture from Montreal helps.

https://www.redbullracing.com/int-en/ga ... grand-prix

So that is an interesting picture. Do we know what day that picture was taken and where....wondering about the conditions, corner and speed.

[F1NAC]

Still think you need to find more pictures of rake than the one of the car exiting the garage. Which, for all we know, might have just been raised in the rear to test something. We have no evidence that this didn't drop back down to regular high after it travel 1cm after this picture was taken. Even your picture of the new larger diffuser openning has no rake.

Maybe this picture from Montreal helps.

https://www.redbullracing.com/int-en/ga ... grand-prix

So that is an interesting picture. Do we know what day that picture was taken and where....wondering about the conditions, corner and speed.

That looks like entry into pitlane. Also car might looked higher because wet tyres give them a bit more clearance. So if that is pitlane entry, somewhere around 100 kph upon slowing down fo pit limiter?

[Hoffman900]

You cannot say rake is not relevant. No technical or evidential grounds to say that at all.
The whole point of having rake in the car is the increase the effective volume of the diffuser, and thus the expansion ratio. If the floor design is not understood, then that's even more reason to not draw conclusions on what is relevant or not. The rake will give the car more downforce, even for a tunnel car. At very high speeds, such as on the straight, all the downforce may not be needed so we have seen trick suspensions where the rear comes down. That still holds with the tunnel cars, maybe its more tricky to control, who knows, but not seeing why the principle would not apply to both philosophies.

It’s not the whole point and there are chassis balance implications as well.

You guys need to stop hanging your hat on outright speculation.

[diffuser]

Maybe this picture from Montreal helps.

https://www.redbullracing.com/int-en/ga ... grand-prix

So that is an interesting picture. Do we know what day that picture was taken and where....wondering about the conditions, corner and speed.

That looks like entry into pitlane. Also car might looked higher because wet tyres give them a bit more clearance. So if that is pitlane entry, somewhere around 100 kph upon slowing down fo pit limiter?

I was thinking they had an off at the hairpin in the rain.

edit

After looking at the picture some more and looking at the track via google maps I can confirm that is 21 - 27 meters after the pit lane limiter line (so 80 KPH).

[Andi76]

You cannot say rake is not relevant. No technical or evidential grounds to say that at all.
The whole point of having rake in the car is the increase the effective volume of the diffuser, and thus the expansion ratio. If the floor design is not understood, then that's even more reason to not draw conclusions on what is relevant or not. The rake will give the car more downforce, even for a tunnel car. At very high speeds, such as on the straight, all the downforce may not be needed so we have seen trick suspensions where the rear comes down. That still holds with the tunnel cars, maybe its more tricky to control, who knows, but not seeing why the principle would not apply to both philosophies.

With the ground effect cars rake is less beneficial. The old cars benefitted from rake(and ground effect) because the air was accelerated in the t-tray area. Also the extension ratio of the diffusor increased and the aoa of the rear wing was higher and the whole car had some kind of "aoa". With the ground effect cars this changed dramatically and rake is not as efficient. You raise the car where it has to be low and lessening the ground effect. Also the rear-wings is less efficient with these new cars, so maybe the additional drag does more harm than good. At the end of the day it probably depends on the design and where the throat is, but rake is definetely not as beneficial and relevant as it used to be. Thats also the reason why we Ross Brawn said that rake will almost disappear with these kind of cars, and thats exactly what has happened.

[Edax]

So that is an interesting picture. Do we know what day that picture was taken and where....wondering about the conditions, corner and speed.

That looks like entry into pitlane. Also car might looked higher because wet tyres give them a bit more clearance. So if that is pitlane entry, somewhere around 100 kph upon slowing down fo pit limiter?

I was thinking they had an off at the hairpin in the rain.

edit

After looking at the picture some more and looking at the track via google maps I can confirm that is 21 - 27 meters after the pit lane limiter line (so 80 KPH).

Yeah, sorry didn’t have time to look it up, but it should be pit lane since there is no other place where you can make this shot with the camera on the ground. Everywhere else is walled off.

So what’s the verdict? Of course the whole car is a lifted by the intermediates, but it looks to me like there is a slight tilt to the floor.

[diffuser]

That looks like entry into pitlane. Also car might looked higher because wet tyres give them a bit more clearance. So if that is pitlane entry, somewhere around 100 kph upon slowing down fo pit limiter?

I was thinking they had an off at the hairpin in the rain.

edit

After looking at the picture some more and looking at the track via google maps I can confirm that is 21 - 27 meters after the pit lane limiter line (so 80 KPH).

Yeah, sorry didn’t have time to look it up, but it should be pit lane since there is no other place where you can make this shot with the camera on the ground. Everywhere else is walled off.

So what’s the verdict? Of course the whole car is a lifted by the intermediates, but it looks to me like there is a slight tilt to the floor.

There is, not sure what the purpose of it is. might be just for pitch control at montreal... I don't think it's for aero ...

We have see SAT run More rake ...



But in high speed corners you usually see stuff like ...



Latios says viewtopic.php?p=1049768#p1049768

Rake philosophy of different teams
A large rake angle means that the whole car is tilted forward, which can make the front wing closer to the ground, the angle of attack(AoA) is larger, more ground effect, and the front wing generates more downforce; the AoA of the rear wing is also larger with high rake, so downforce is greater; With larger rake, the back of floor (diffuser) is off the ground with larger gap, so larger diffuser area, but edge of sideplane of diffuser is further to ground. Greater rake also often brings greater total drag since more frontal area.

Small rake can reduce the ground clearance of rear, i.e. ground clearance on both sides of the floor and diffuser, thereby reduce air flowing into the bottom of the car, and increase downforce.

Some teams may use a larger rake, hoping to generate more downforce at the front of the floor and could (also can choose not to) reduce front wing ground-clearance, then more downforce by front wing. Such as the high front wing + high rake of Aston Martin and the high rake of AlphaTauri. The high front wing creates lower downforce, but the airflow to the bottom of the car is cleaner. Through the design of high rake and fence, the floor can generate more downforce, and less balance impact when following another car (when front wing downforce is reduced).

[diffuser]

IMHO and I am by no means an anything expert. The floor creates DF by squeezing as much air as you can under the foor with it being sealed around the sides. The more you squeeze the air without causing it to stall, the faster it travels, the more DF you create. That to me means that rake when you need DF, isn't a good idea. It makes it harder to seal the sides, it decreases the amount of air that comes in from the front and increases the space for air (slowing it) instead of squeezing it and therefore accelerating it.

I can see now that there may be some benifits at certain tracks where you may want to give away some rear DF for some front DF at lower speeds to find balance that you maybe be searching for.

Think of all the shenanigans that Merc has been playing with it's driver to get the minimum ride hight raised. They can't stop their cars from bouncing , therefore, punishing thier drivers. Raising the ride hight for everyone would decrease DF, solve the Merc's problem and they can stay competative. The ride hight change would effect everyone until they could find a way around it, it would give merc time to find solusions.

[Edax]

I was thinking they had an off at the hairpin in the rain.

edit

After looking at the picture some more and looking at the track via google maps I can confirm that is 21 - 27 meters after the pit lane limiter line (so 80 KPH).

Yeah, sorry didn’t have time to look it up, but it should be pit lane since there is no other place where you can make this shot with the camera on the ground. Everywhere else is walled off.

So what’s the verdict? Of course the whole car is a lifted by the intermediates, but it looks to me like there is a slight tilt to the floor.

There is, not sure what the purpose of it is. might be just for pitch control at montreal... I don't think it's for aero ...

We have see SAT run More rake ...

https://pic3.zhimg.com/80/v2-3513113e2b ... a_720w.jpg

But in high speed corners you usually see stuff like ...

https://pbs.twimg.com/media/FV9VvHHXkAA ... name=large

Latios says viewtopic.php?p=1049768#p1049768

Rake philosophy of different teams
A large rake angle means that the whole car is tilted forward, which can make the front wing closer to the ground, the angle of attack(AoA) is larger, more ground effect, and the front wing generates more downforce; the AoA of the rear wing is also larger with high rake, so downforce is greater; With larger rake, the back of floor (diffuser) is off the ground with larger gap, so larger diffuser area, but edge of sideplane of diffuser is further to ground. Greater rake also often brings greater total drag since more frontal area.

Small rake can reduce the ground clearance of rear, i.e. ground clearance on both sides of the floor and diffuser, thereby reduce air flowing into the bottom of the car, and increase downforce.

Some teams may use a larger rake, hoping to generate more downforce at the front of the floor and could (also can choose not to) reduce front wing ground-clearance, then more downforce by front wing. Such as the high front wing + high rake of Aston Martin and the high rake of AlphaTauri. The high front wing creates lower downforce, but the airflow to the bottom of the car is cleaner. Through the design of high rake and fence, the floor can generate more downforce, and less balance impact when following another car (when front wing downforce is reduced).

I agree that the cars seems pretty flat in most corners.

Makes me think. Wouldn’t more suspension travel at the rear also help with the traction out of a slow corner? The launch onto the straight in Montreal is pretty important for overtakes and defense.

[johnny comelately]

Have you people already discussed this rear suspension mechanism and ride height affect on aero (8:20 mark) ?

[AR3-GP]

Also, I'm getting confused between Craig's drawing and the actual RB rear end. The detail at the bottom looks completely different:

https://i.postimg.cc/hG0M0rPy/Image-3.jpg

The rear suspension concept was discussed, if you click through from the above quoted post. Whether it's doing some ride height jacking? No one can be sure.