Red Bull RB12 TAG-Heuer

[carisi2k]

The RB12 does look good and I think that Red Bull may also have been sand bagging during testing even when using the super and ultra soft tyres. Things like that second air intake behind the drivers head below the main intake so that they didn't have to go to a larger airbox and also to allow them to reduce the sidepod size. I'm assuming that it is for cooling the battery storage. There is so many nice details on the rb12 that make it look like it will be fast regardless of how many horses they have at Melbourne.

[Blackout]

Like AMuS noticed, the cars which have a big rake like the RBR (Mclaren, STR, FI) have the lowest speed trap. Newey admitted it few years ago. That aero settings costs few hmh in the speed traps
http://www.f1technical.net/forum/viewto ... 91#p626191

[Blackout]

But I wonder why because AFAIR with
-a big ass diffuser/expansion ratio under the floor
-a lower FW thanks to the rake (some studies proved they can reduce front wheels drag)
-'flatter' rear wing
The RBR should have a nice lift/drag ratio. It certainly has but I'm sure Newey (and Marshall?) said this high rake produces quite a bit of drag.

[FW17]

But I wonder why because AFAIR with
-a big ass diffuser/expansion ratio under the floor
-a lower FW thanks to the rake (some studies proved they can reduce front wheels drag)
-'flatter' rear wing
The RBR should have a nice lift/drag ratio. It certainly has but I'm sure Newey (and Marshall?) said this high rake produces quite a bit of drag.

With a bigger rake wont there be a bigger frontal area? Even with shallower wings, more rake could mean more area.

[Juzh]

But I wonder why because AFAIR with
-a big ass diffuser/expansion ratio under the floor
-a lower FW thanks to the rake (some studies proved they can reduce front wheels drag)
-'flatter' rear wing
The RBR should have a nice lift/drag ratio. It certainly has but I'm sure Newey (and Marshall?) said this high rake produces quite a bit of drag.

If you remember, RB9 had a humongous amount of rake, but it allowed them to run very shallow rear wings and often be quickest on the straights as well, or at least equal best, which was unusual for RB cars. RB is pretty much forced into running a compromised setup in almost any given track, which is evident in the amount if wing they run. I doubt they'd be going for an all out as much rake as possible if it cost them significant penalty in drag.

[bhall II]

...I'm sure Newey (and Marshall?) said this high rake produces quite a bit of drag.

With a bigger rake wont there be a bigger frontal area?

Yep. Plus, regardless of efficiency, anything that increases downforce will also increase induced drag.

[tmoneyr007]

...I'm sure Newey (and Marshall?) said this high rake produces quite a bit of drag.

With a bigger rake wont there be a bigger frontal area?

Yep. Plus, regardless of efficiency, anything that increases downforce will also increase induced drag.

Don't forget though, Diffuser DF is the most efficient way to "bolt-on" downforce.

[bhall II]

The increased ride height concomitant with adding rake reduces the efficiency of the diffuser.

Rake is a trade of sorts. The diffuser is weakened, but the front wing and the front of the floor are strengthened, and the car's center of pressure is moved forward.

[trinidefender]

The increased ride height concomitant with adding rake reduces the efficiency of the diffuser.

Rake is a trade of sorts. The diffuser is weakened, but the front wing and the front of the floor are strengthened, and the car's center of pressure is moved forward.

This isn't always true. Referencing this article by Willem Toet: https://www.linkedin.com/pulse/how-do-m ... illem-toet

"Diffusers are ride height sensitive over part of the ride height range with peak performance being at a relatively low ride height. Move lower and a dramatic loss of performance and aerodynamic instability results. A high angle diffuser will have peak (downforce generating) performance at higher ride heights while a lower angle diffuser will perform best at lower ride heights. "

Here is a graph that shows diffuser ride height vs downforce produced.


Here is a graph of different diffuser angles and their corresponding downforce levels at different ride heights:


Therefore the designers will have to match the rake and how much a car squats at speed (which can obviously be adjusted) with the design of the diffuser. It is my belief that the rake the aerodynamicist are running is only done so because they are confident that with the overall picture of a lower front wing and a higher angle diffuser to work better with a higher rake angle the overall downforce level on the car will be increased.

On the subject of rake turning the floor itself into a diffuser, Willem writes this:
" In Formula 1 diffusers are expanded both in side view and in plan view. This is in part because the height limit imposed by regulation is well below the aerodynamic optimum. There is still a positive impact on pressures and hence forces on the flat part of the floor. The trend towards running ever higher rear ride heights in Formula 1 will be in part because the entire floor can become a diffuser, in part because the teams have learned how to use vorticity to take advantage of all that air that otherwise passes under the car almost “unused”."

P.s. I know most of this has been me just quoting however I am not going to pretend I know better or try to change the words of an actual formula 1 aerodynamicist. Therefore I just elected to use the quotes that apply to this post.

[bhall II]

Far be it from me to disagree with Mr. Toet, even if what's implied by saying the entire floor can be a diffuser still just seems kinda weird to me.

"The trend towards running ever higher rear ride heights in Formula 1 will be in part because the entire floor can become a diffuser, in part because the teams have learned how to use vorticity to take advantage of all that air that otherwise passes under the car almost “unused”."

Nonetheless, when I mentioned strengthening the front of the floor, that's what I had in mind.

Bargeboards, turning vanes, vortex generators, sculpted horns, those little flip-up things on the outside edges of the floor, etc., are all used to create downforce with air flow that would ordinarily be discarded, so to speak, to improve the efficiency of the diffuser proper and nothing else.

[Blackout]

So if we summarise, a 'rakeless' car like the Merc should have a lower peak of DF at the front wing, a lower peak at the floor leading edge, a higher peak at the diffuser and a higher and straighter curve under the floor because of a more homogeneous df distribution under the more efficient floor?
And what's the point on tilting the center of pressure forward? most of the weight and the grippier tires are at the rear!?

[Just_a_fan]

The cars are front limited so getting the front to turn in smartly is key to keeping the drivers happy.

The Mercs are hardly rakeless but I did note your use of "".

[bhall II]

To go along with that, and even though I'm a bit leery of overgeneralizing - not that it's ever stopped me before - I tend to think the strength of the front end defines a car's potential, and the strength of the rear end defines the front end's potential, i.e. the car's balance. They both have to work together. But, ultimately, it's all about yaw rate, and that means a grippy front.

One concrete benefit of moving the center of pressure forward is better tire management, because understeer kills tires in a hurry - a big reason why drivers can't linger in another car's wake for too long.

[PlatinumZealot]

Different Engine covers.

[PlatinumZealot]

The increased ride height concomitant with adding rake reduces the efficiency of the diffuser.

Rake is a trade of sorts. The diffuser is weakened, but the front wing and the front of the floor are strengthened, and the car's center of pressure is moved forward.

This isn't always true. Referencing this article by Willem Toet: https://www.linkedin.com/pulse/how-do-m ... illem-toet

"Diffusers are ride height sensitive over part of the ride height range with peak performance being at a relatively low ride height. Move lower and a dramatic loss of performance and aerodynamic instability results. A high angle diffuser will have peak (downforce generating) performance at higher ride heights while a lower angle diffuser will perform best at lower ride heights. "

Here is a graph that shows diffuser ride height vs downforce produced.
https://media.licdn.com/mpr/mpr/shrinkn ... ZTAxOA.jpg

Here is a graph of different diffuser angles and their corresponding downforce levels at different ride heights:
https://media.licdn.com/mpr/mpr/shrinkn ... YTU0MA.jpg

Therefore the designers will have to match the rake and how much a car squats at speed (which can obviously be adjusted) with the design of the diffuser. It is my belief that the rake the aerodynamicist are running is only done so because they are confident that with the overall picture of a lower front wing and a higher angle diffuser to work better with a higher rake angle the overall downforce level on the car will be increased.

On the subject of rake turning the floor itself into a diffuser, Willem writes this:
" In Formula 1 diffusers are expanded both in side view and in plan view. This is in part because the height limit imposed by regulation is well below the aerodynamic optimum. There is still a positive impact on pressures and hence forces on the flat part of the floor. The trend towards running ever higher rear ride heights in Formula 1 will be in part because the entire floor can become a diffuser, in part because the teams have learned how to use vorticity to take advantage of all that air that otherwise passes under the car almost “unused”."

P.s. I know most of this has been me just quoting however I am not going to pretend I know better or try to change the words of an actual formula 1 aerodynamicist. Therefore I just elected to use the quotes that apply to this post.

Good post Triniman.
These regs really limit the height of the diffuser. The angle is so narrow that teams are running concave diffusers to try to make up.