Red Bull RB7 Renault

[Lindz]

The 'trumpet exhaust' is what they run with KERS since it needs more cooling. The smaller letterbox looking exhaust exit is what they run with no KERS (like Australia GP, post-FP1).

[PlatinumZealot]

You guys should look for where the KERS oil cooler is. I am sure it is not much different from other cars.

[hollowBallistix]

With the amount of rake their running on the car, isn't that like increasing the effective length of the diffuser ?

[BreezyRacer]

With the amount of rake their running on the car, isn't that like increasing the effective length of the diffuser ?

Yes, and that's a well known way to increase downforce PROVIDED that it's designed in at the beginning. You can easily improve the aero on some generic sedan by raking it but with an optimized design like an F1 car, you really need to start out that way get use out of it, otherwise you'll get things like separated flow, turbulence in the diffuser box, etc.

[hollowBallistix]

don't know if the term is right, but the "choke" point occurs at the tea tray, which accelerates the air under the car, then with the increased rake & diffuser this makes the car more efficient at creating downforce without drag, added to that the exhaust gasses to help then you've got a good package? is that about right ?

[ringo]

What the rake really does is compensate for the boundary layer build up.
Too much may lose the effect of creating high velocity air under the car.
Having the rake just about offset to the boundary layer gradient is the right angle to have.
Then again the flexi wings come into it as well.

About the KERS, as suspected it's a vibration problem, so i don't think it will be huge problem to fix. Redbull just need data on it, then dampen the system accordingly.

[shelly]

What the rake really does is compensate for the boundary layer build up.
Too much may lose the effect of creating high velocity air under the car.
Having the rake just about offset to the boundary layer gradient is the right angle to have.

ringo you are wrong. Rake gives you front downforce and overall downforce gain

[raymondu999]

Wouldn't some teams then, "design" some rake into their cars? Eg. Take a sideways drawing of a McLaren or a whatever F1 car. Instead of having the floor level with the edge of the paper at that perspective, imagine drawing a line which is lower towards the front of the car and higher towards the back (ie the "stock" setup would already have rake)

[ringo]

What the rake really does is compensate for the boundary layer build up.
Too much may lose the effect of creating high velocity air under the car.
Having the rake just about offset to the boundary layer gradient is the right angle to have.

ringo you are wrong. Rake gives you front downforce and overall downforce gain

ok. care to explain how you get those front downforce and over all gain ?

[BreezyRacer]

Wouldn't some teams then, "design" some rake into their cars? Eg. Take a sideways drawing of a McLaren or a whatever F1 car. Instead of having the floor level with the edge of the paper at that perspective, imagine drawing a line which is lower towards the front of the car and higher towards the back (ie the "stock" setup would already have rake)

That's what Newey did. I'm surprised others dismissed it.

[ringo]

Wouldn't some teams then, "design" some rake into their cars? Eg. Take a sideways drawing of a McLaren or a whatever F1 car. Instead of having the floor level with the edge of the paper at that perspective, imagine drawing a line which is lower towards the front of the car and higher towards the back (ie the "stock" setup would already have rake)

It doesn't change much in the design, since the regulations are referenced to the refence plane, all horizontal, vertical measurements. Though starting with an angle helps to form aerodynamics better, the engine and gearbox alignment, the nose shape, and fuel tanke shape.
Lets just say Redbull can run a raked floor with their engine, and gearbox perfectly horizontal to the ground; the air intake, sidepod inlets, driver seat back perfectly vertical, while if Mclaren run the same rake, their engine and gearbox would be tilted at the rake angle and so will the other areas listed above.
So you see where this is going. Not a huge deal but it's a fundamental difference in the design philosophy.

The redbull body is in a naturally raked stance.
And works at 100% efficiency in this stance as opposed to another team tilting their car and getting different behavior from the side pods and engine intake.

[raymondu999]

yup that's what I thought. The "base" stance would be raked.

[Lindz]

^And things like the top of the sidepods and coke bottle shape would work with rake designed from the outset, whereas adding rake to an existing design MAY cause more frontal area and/or drag.

[BreezyRacer]

What the rake really does is compensate for the boundary layer build up.
Too much may lose the effect of creating high velocity air under the car.
Having the rake just about offset to the boundary layer gradient is the right angle to have.

ringo you are wrong. Rake gives you front downforce and overall downforce gain

ok. care to explain how you get those front downforce and over all gain ?

Hi Ringo
With a rake the front of the inlet is expanding right from the inlet. This does create a low pressure area just behind the inlet, so it does move the center of pressure forward a bit. I would imagine this would be especially relevant with a defined flat bottom like F1 is mandated.

[marekk]

Flat plate with 1400mm width and 3 degree rake (negative angle of attack) will give 180kg of downforce at 250kmh (60kg for every 1 degree). Not taking ground effect (up to 50% increase in downforce) into account.

Of course there is some bodywork up there, so real numbers will be lower, but i don't think even HRT or Virgin would design their cars not taking this fact into account.