Red Bull RB7 Renault

[PlatinumZealot]

I wasn't even trying to relate RedBull's use of rake and their diffuser in the beginning.
I was talking about raise in center of gravity when you add rake. That is why I brought up production cars saying that manufacturers did not see this as a major disadvantage.

Then I think someone mentioned downforce on production cars, and I said that some of them actually do make downforce...SO.. let us not get it twisted.

[AbbaleRacing77]

Yes but car manufactures dont see the addition of cupholders as a disadvantage to there center of gravity either... Your comparing apples and oranges. In the past Ive noticed major handling differences with a 2mm change in rake on some of my cars. Point being is that you dont run an absurd amount of rake like that unless you have a huge handling deficiency in the car OR somehow using it to your advantage to create large amounts of downforce.

Im gonna make an educated guess and say that theyre using it to create huge amounts of downforce. With that said... the amount of downforce that theyre making with this little trick that they've developed by creating a virtual skirt with the exhaust, and in a sense doubling the size of there diffuser must be HUGE in order to out weigh all the disadvantages of running that much rake in the car.

If you think about it not only is the high rake making the diffuser bigger height wise but it might also be lengthening it by allowing air to start expanding much earlier (at the middle of the car).

Normally a car with this much rake would be at a huge disadvantage because its either inherently very imbalanced or they just have a terribly snappy over steery setup, not to mention worsened center of gravity. I used to race a formula enterprise car when i was 16 and it was the only car that i ever ran tons of rake on because it lacked front downforce combined with crappy spec shocks and had understeer like theres no tomorrow. I think its fair to say that red bull doesnt lack front downforce and doesnt have crappy shocks. Due to the "virtual blown skirts" on the red bull they are able to simulate something very aerodynamically advanced that cleverly allows them to bypass the FIA set diffuser dimensions creating a virtual super floor/diffusor.

[shamikaze]

We know from pic's that RB uses a very soft suspension due to the amount of roll during corners on the car.

Could it not be that due to the high rake used, they must use this "soft" suspension so that when the car settles in a turn and rolls a bit, the CoG actually is lowered just that little bit. I don't think they use that soft suspension because they could not get stiffer damper/springs. There lust be a specific reason for it and my idea is that this probably would be a contributing to the aero-efficiency (linked to FW-flexing/pivotting and .

Does anyone have an educated guess how the roll as seen on the RB's would or could affect the performance of the floor/diffuser combo ?

[marcush.]

We know from pic's that RB uses a very soft suspension due to the amount of roll during corners on the car.

Could it not be that due to the high rake used, they must use this "soft" suspension so that when the car settles in a turn and rolls a bit, the CoG actually is lowered just that little bit. I don't think they use that soft suspension because they could not get stiffer damper/springs. There lust be a specific reason for it and my idea is that this probably would be a contributing to the aero-efficiency (linked to FW-flexing/pivotting and .

Does anyone have an educated guess how the roll as seen on the RB's would or could affect the performance of the floor/diffuser combo ?

Soft in roll but it cannot be soft in heave and pitch methinks ..you need something to maintain the rake at high speed/downforce and without springforce the back will come down and the bumpstops will determine the final rear rideheight but thats stiff not soft.

[lillschumi]

one thing i come to think of regarding softness and rake of the RB7 (and i´m no engineer and have no expertise of it) is about the CoG.

i have understood that engineers want the CoG as close to the ground as possible. I have been racing in go-carts in junior years and there the CoG to play with is mainly your body. Ihave tried various technics but the fastes is always to lean opposite wheree curve is going, by this you add pressure to the side of the car with most grip (and helps relieve the inner part of axle which is not diffed) by extending latteral g-forces.

Could it be with a higher rake and softer suspension you actually get somewhat higher CoG but that higher CoG produces more mechanical grip because the pressure comes from "top down" so to speak.

[PhillipM]

^That's just down to the way the cart suspension works tbh, you'll find most F1 cars will be trying to keep as much weight on the inside wheels as possible (within the confines of the aero effect from the wishbones and handling balance/tyre heating)

[MrBlacky]

Yup, but I really can't understand why the cart should go faster round the corner when you lean to the right in a left hander. When I go carting I try to keep as much weight as possible on the inside to not to overload the outer tyres.

[HampusA]

It´s true. Heard it from many fast go-cart drivers.
Another tip is to lean back as much as you can during braking (for carts with only rear brakes)

It´s probably down to the relatively little weight you put on go-cart tires including the driver. Therefore it works to add more weight to them instead of an F1 car that already weighs 600+kg.

[PlatinumZealot]

Yes but car manufactures dont see the addition of cupholders as a disadvantage to there center of gravity either... Your comparing apples and oranges. In the past Ive noticed major handling differences with a 2mm change in rake on some of my cars. Point being is that you dont run an absurd amount of rake like that unless you have a huge handling deficiency in the car OR somehow using it to your advantage to create large amounts of downforce.

Im gonna make an educated guess and say that theyre using it to create huge amounts of downforce. With that said... the amount of downforce that theyre making with this little trick that they've developed by creating a virtual skirt with the exhaust, and in a sense doubling the size of there diffuser must be HUGE in order to out weigh all the disadvantages of running that much rake in the car.

If you think about it not only is the high rake making the diffuser bigger height wise but it might also be lengthening it by allowing air to start expanding much earlier (at the middle of the car).

Normally a car with this much rake would be at a huge disadvantage because its either inherently very imbalanced or they just have a terribly snappy over steery setup, not to mention worsened center of gravity. I used to race a formula enterprise car when i was 16 and it was the only car that i ever ran tons of rake on because it lacked front downforce combined with crappy spec shocks and had understeer like theres no tomorrow. I think its fair to say that red bull doesnt lack front downforce and doesnt have crappy shocks. Due to the "virtual blown skirts" on the red bull they are able to simulate something very aerodynamically advanced that cleverly allows them to bypass the FIA set diffuser dimensions creating a virtual super floor/diffusor.

You see, the RB7 was designed with the rake built in, so they make the geometry of the suspension to negate the ill effects you speak of. Looking on the photos of the RB7 the suspension is set very low to the floor, even some parts below the floor. The kinematics of the car is as if there was no extreme rake at all.

Now as per the aerodynamics, again, I did not want to discuss from the viewpoint of EDB, because that was done and dusted in the Exhaust blown diffuser thread, we already covered how the EBD works with ReBull's rake.

But because of the replies to my posts, what I am more focused on is, what is going to happen to RedBull when Exhaust overrun is disabled. In other words - Mclaren, Ferrari and RedBull more or less aerodynamically equalised how will the extreme rake of the floor affect RedBull in all aspects. I want to hear what you guys think of what is going to happen.

[MrBlacky]

It´s true. Heard it from many fast go-cart drivers.
Another tip is to lean back as much as you can during braking (for carts with only rear brakes)

It´s probably down to the relatively little weight you put on go-cart tires including the driver. Therefore it works to add more weight to them instead of an F1 car that already weighs 600+kg.

Hm okay thanks, have to to try it by myself. But now back to topic

[hardingfv32]

The carting reference is a very poor comparison to F1 cars when discussing weight transfer.

In a F1 car, almost all the weight transfer is caused by a force acting on the CG. They actual movement of the CG is very small considering the amount of roll and CG height.

In a cart you have a driver that move the CG a good amount. While this effect is greater in a cart, the cart still gets most of its weight transfer from a force acting on the CG.

What benefit is a car soft in roll?

Brian

[hardingfv32]

Even with the rake built in to the RB, we can still expect the CG to be high than other cars?

Brian

[hardingfv32]

"Mclaren, Ferrari and RedBull more or less aerodynamically equalised how will the extreme rake of the floor affect RedBull in all aspects"

1) We have no evidence that the RB diffuser seals better than others.

2) We can not decide what flow mechanism the BR exhaust uses to seal the diffuser.

3) Scarbs in a recent interview states his F1 engine source claim that RB does not use an aggressive off throttle mapping when compared to others.

4) The off throttle mapping is only used for 20% of a lap on average. One would expect that aero system is going to be optimized for the other 80% when the off throttle mapping ends.

Brian

[Ferraripilot]

But because of the replies to my posts, what I am more focused on is, what is going to happen to RedBull when Exhaust overrun is disabled. In other words - Mclaren, Ferrari and RedBull more or less aerodynamically equalised how will the extreme rake of the floor affect RedBull in all aspects. I want to hear what you guys think of what is going to happen.

I suspect RB will have a balance problem off-throttle during turn entry. If this is the case, RB will do one of a couple things: first they could change the rake angle so to even out what the front end is making in terms of DF to the rear end, or the second option is to leave things as they are and drive around the issue relying on their substantial turn-in speeds at high-speed entry corners. Although I have a feeling that front wing of theirs is going to create a substantial balance issue forcing the rake change I spoke of earlier. I am wondering if their front suspension geometry is dependent on the substantial rear end downforce as well. I suspect it is....

[hardingfv32]

Is the RB rake only a benefit when they are using the off throttle mapping? I think not.

Why do anything the compromises the 80% of the lap that you are on the throttle?

Brian