Mercedes GP W02

[atanatizante]

Now compared to last year in the same period of time, who could tell anything against their truthful words regarding the updates they promised ?
I think now they delivered the goods ...

[atanatizante]

The idea of the Merc exhaust is exactly the same as that of the blown diffuser Red Bull pioneered last year. That is, re-energizing the airflow as it reaches the rear of the car before it gets to the diffuser...

I think that secondary to this effect is the fact that it creates some kind of a skirt in order to : 1. channel the flow of air underneath the floor towards the diffuser and 2. accelerate this flow in this "new channel". Please correct me if I`m wrong ...

Another issue is regarding the gradient temperature underneath the floor where the exhausts are positioned. In this case which are the benefits?

... Now if you put the exhaust too far forwards, you hit a very wide portion of the flow. So wide that some of it will hit the rear tyres ...

Last year they have had some real issues with warming up the rear tyres (the hard ones in particular) even on tracks with high temperatures, which were unsolved till the end of the season. So do you think now they are hitting on those to solve the problem? In a less degree maybe ...

[ForMuLaOne]

There are two concepts to me:


RB tries to maintain airspeed by reducing volume od their bodywork in a smooth way. Therefore the dont have to fill a low pressure area but try to accelerate it.


Merc tries to fill up a low pressure area behind the sidepots, the air from above helps to suck air from the diffuser.

So to me RB has smaller volume of faster airspeed in the rear section and MB has larger volume. Interesting is the average.

[racer_boy]

Has anybody figured out whether the floor on the car actually channels any air to some part of the rear diffuser? Its hard to tell but the floor nearly looks too thick where it meets the start of the diffuser?

[bot6]

I don't think they are allowed to "shape" the underside of the floor since ground effect cars were banned.

The reason the floor seems very thick is because of the way it is built. Most teams seem to use a monolithic carbon laminate for the floor, so essentially one thick skin of carbon fiber and epoxy. That makes the floor thinner.
Merc seem to have used a sandwich structure, so two thinner skins of carbon fiber with a foam or honeycomb structure in the middle. This makes a much stiffer structure for the same weight, but is more difficult and more expensive to make, and more fragile against impacts. Also, it's harder to make complex shapes this way.

[dren]

There are two concepts to me:


RB tries to maintain airspeed by reducing volume od their bodywork in a smooth way. Therefore the dont have to fill a low pressure area but try to accelerate it.


Merc tries to fill up a low pressure area behind the sidepots, the air from above helps to suck air from the diffuser.

So to me RB has smaller volume of faster airspeed in the rear section and MB has larger volume. Interesting is the average.

This is what I was thinking. There has to be some pros to the shorter wheel base to go the way the Merc did over the Red Bull idea. Or more like the aero idea Merc is going with works best with a short wheel base.

[willga]

I don't think they are allowed to "shape" the underside of the floor since ground effect cars were banned.

The reason the floor seems very thick is because of the way it is built. Most teams seem to use a monolithic carbon laminate for the floor, so essentially one thick skin of carbon fiber and epoxy. That makes the floor thinner.
Merc seem to have used a sandwich structure, so two thinner skins of carbon fiber with a foam or honeycomb structure in the middle. This makes a much stiffer structure for the same weight, but is more difficult and more expensive to make, and more fragile against impacts. Also, it's harder to make complex shapes this way.

All teams use a honeycomb structure for the floor - it's the only way to achieve the required stiffness without the component weighing a tonne. For complex shapes, nomex honeycomb is used as it is more flexible than aluminium honeycomb, or else a machined polyurethane foam core is used for the really tight and complex stuff.
The sandwich is not used in areas where thinness is a priority, such as under the engine and monocoque, so that the C of G is not raised - in fact, some teams have experimented using shim-steel under the engine, to get it as low as possible.
Obviously, at the aerodynamic edges of the floor, the surfaces have to taper away to nothing - it is the aggressiveness of the chamfer or radius forming this taper which will give the visual effect of how thick the floor is.

[bot6]

If you look at the floor of the Red Bull for example, it seems to stay wafer thin at least until it reaches the sidepod. That result can only be obtained by building at least that outer part in monolithic. The merc, however, has the characteristic "step" on the edges that characterizes sandwich structures.




See the difference?

Red Bull might use a sandwich structure inside the sidepods, but it seems unlikely, as this would mean raising all of the components inside a few cm, leading to a higher CG. The floor being the lowest part of the car, it is "allowed" to be heavier.

Also, most cars don't really use the floor for structural purposes, as most of the efforts are taken by the engine, safety cell and crash structure. The bodywork and floor are just there for purely aerodynamic reasons.

Also, since the Red Bull exhaust duct acts as a reinforcement beam, there is no need to make the floor part stiffer.

Another interesting thing to notice on that top view of the Merc is the angle of the driveshafts. What Williams have done vertically (very low gearbox for cleaner flow to the rear), Mercedes seem to have done horizontally. The gearbox is positioned quite far forwards relative to the rear wheels. It is also obviously very narrow. This has several advantages: clean flow to the rear thanks to the narrow gearbox, and more space for the diffuser due to the forward position of it.

[shelly]

Merc w02 distinctive feature is the shorter wheelbase, in comparison with others.

We can suppose that they have found a compensation for shorter coke bottle by blowing the exhaust on the sidedpods; and we know that weight distribution this year has mininum weight mandatory on front and rear axles (so it is almost fixed in quali trim, and theoretically more free in race for fuel weight, but the tank will be more or less centered).

Considering these factors, why do you think they have gone for shorter wheelbase? Is it just weight saving? Scarbs tell us that wheelbase is not related to agility/stability (because it is just a few percent variation): so what is the motivation for merc choice in your opinion?

[ggajic]

One of the reasons for choosing shorter wheelbase might be reason that Schumacher prefer oversteer. Shorter wheelbase cars are more aggressive. Have in mind that no matter what Mercedes-GP/Mr. Ross Brawn says this car is tailored with Schumacher driving style on mind..

[ringo]

The car can be stiffer longitudinally.
But i think teams would like it if the car was a little flixible in the belly.
So it's not clear. Agility is the only logical thing and maybe tyre wear.

[bot6]

Brawn said that they made calculations and that the shorter transmission seemed to help the diffuser work better.

[atanatizante]

Which are the benefits of the winglets which are placed above and underneath the side of the rear wheel drum? Why Merc didn`t do that?

Another question is regarding the diffuser construction. Why they didn`t do a "multi-decker diffuser" ? I don`t think it`s in place the DDD ban rule, because they don`t do holes in the floor, now they just have to put one above the other, hence multiply the effect ...

[bot6]

It doesn't work that way unfortunately. The diffuser itself is not the part that creates the downforce, so stacking tons of diffusers one on top of each other would not help.

The downforce is created by the flow of air under the floor of the car. The quicker the air goes under the car, the more downforce is created.

The diffuser is just a part that sucks air out of the back of the car to accelerate the flow under it.

For the winglets, I think you are referring to the ones on the rear brake ducts. The new front brake ducts use something similar on the Mercedes, but the rear ones are more simple.

Winglets create downforce, but also increase drag, which hurts your top speed so it's not always better to add winglets.

Also, these seem to be used mainly to stabilize airflow at the rear and work in conjunction with the huge cooling aperture at the back of the Red Bull. The corresponding aperture on the Merc is much smaller, limiting the usefulness of such winglets.

[Just_a_fan]

Which are the benefits of the winglets which are placed above and underneath the side of the rear wheel drum?

The winglets next to the rear wheels are actually classed as part of the brake duct - bizarre rule interpretation by the FIA there.

Their job is two fold - one is to generally condition (improve) airflow around the inside of the wheels, the other is to generate downforce directly on to the wheel (and thus the tyre).