Underfloor Analysis: Red Bull vs Ferrari vs Mercedes

As we have been saying since the beginning of the season, the element that creates the greatest differences in terms of performance in Formula 1 is the floor: the Technical Regulations, as written, favors the generation of aerodynamic downforce precisely through this area, and the teams - which they know this well - invest a large portion of the budget at their disposal for the development of this component.

For the same reason, it is understandable why the same teams are so reluctant to show their rivals what is hidden in their underfloor concept... Since the preseason testings in Bahrain, which marked the beginning of 2023, we have never had the opportunity to analyze photos from an underfloor. This up to Monaco, where the logistical difficulties linked to how narrow the Principality track is made it necessary to use cranes to physically move the crashed single-seaters.

The mistakes of Sainz, Hamilton and Perez exposed their cars

Luck (knowing that they are all unharmed, we can say this) meant that, between Friday and Saturday, three drivers from the top teams hit the wall - on whom there was more curiosity about the aerodynamic details of their floors. Sainz in FP2, Hamilton in FP3 and Perez in qualifying gave us some shots that are worth analyzing, to better understand how their cars generate performance.

Red Bull's floor: the most complex of the three

Let's start our analysis from the floor of the Red Bull RB19, practically unmatched in this World Championship. The first impression when seeing the following photo is that the aerodynamic concept has remained the same as last year's RB18, which is perfectly logical given the technical advantage accumulated last season.

Mark Sutton / Motorsport Images

The technical characteristics that distinguish this floor are undoubtedly a central section designed with the aim of channeling more air under the floor of the car itself. This same airflow, having a greater volume in which to move, is destined (due to the mass flow conservation principle) to slow down, which potentially is a problem: the floor-diffuser combination works well when they manage to create low pressure in the underfloor area, a condition which in turn is generated as the flow acquires more speed.

What did the engineers in Milton Keynes invent to speed up the airflow?

Obviously not being able to have mechanical elements at their disposal to "blow" air into the final portion of the floor, the only feature that can help accelerate the airflow (and, as mentioned, decrease its pressure) is the geometry of the central section, which we can improperly call "keel". Indeed at the tail of the keel there are 3 steps which aim to generate vortices, which will make the incoming flow turbulent... in other words, it can be said that when this happens, the airflow is properly re-energised.

A re-energised flow can make the diffuser work better, and Red Bull in turn can draw a greater aerodynamic load from it.

Due to how such floor is designed, there are two potential problems that can arise:

• The contact of the floor edges with the asphalt in the roll phase when cornering;
• The growth of aerodynamic drag as the downforce increases;

For each of these two problems, the technical department led by Adrian Newey and Pierre Waché has thought of a solution, and - perhaps - a way to turn these weaknesses into strengths...

The skids keep the car 'lifted' and prevent wear

When the RB19 - like its rivals - approaches a corner, the vehicle body generates a motion called "roll", whereby the inertia pushes the outside portion of the car against the ground. During a whole race it is easy to understand how this rubbing between the floor edges and the asphalt can cause a wear of the former.

But that's not all! By exploiting ground effect in Formula 1, the close proximity between car and tarmac can generate the annoying phenomenon of porpoising, which is also not desirable.

And it is for these reasons that we find two metal skids, which keep the entire surface at a safe distance from the asphalt: an expedient as simple as useful, which in fact - as we will see later - is used even from rivals at Ferrari and Mercedes. It should also be noted that the presence of the skids makes the wear of the central plank more homogeneous.

Hypothesis: does the diffuser geometry explain the monstrous straight-line speed?

Another photo from the same Perez incident shows a diffuser feature that leads to some technical suggestions. We are referring to the way in which the ramp from the Venturi channels into the diffuser itself has 2 steps on each side, and therefore it's far from linear in its section raising.

Mark Sutton / Motorsport Images

The reason for the presence of these two steps could lie in the desire to stall the entire diffuser only under certain conditions...

If we think about it, no component of a Formula 1 works independently, but each part is functional to what the car does as a whole. The diffuser, for example, generates a certain amount of downforce not only because of how it's made, but also because of its proximity to the beam wing and the rear wing.

Mark Sutton / Motorsport Images

Now, since the ramps of the diffuser must be designed with accurate geometries that prevent stalling, it is safe to assume that the 2-step Red Bull configuration (not at all progressive, as mentioned) does not stall only thanks to the help it receives from the rear wing. To be precise, with the term "help" here we mean an adjustment of the pressure field in the area behind the diffuser which helps the latter not to stall...

But when the RB19 is in a straight line and opens the DRS, there is no more the "support" that the rear wing was giving to the diffuser: not only is this not a problem (since downforce in a straight line is useless), but it even becomes an advantage when the aerodynamic stall also reduces the drag and the car can travel at much higher straight line speeds than the competors!

For the avoidance of doubt, it should be noted that the phenomenon described, however legitimate and functional in theory, is only a hypothesis. And, as such, it is not possible to confirm it 100% unless you have data in hand that only Red Bull has…

Ferrari's floor: the fear of porpoising is restricting its development

At Ferrari, the floor of the SF-23 appears at first glance to be decidedly more basic and less refined than that of the English-Austrian team. The main reason is the fact that for the entire 2022 season, the technical department in Maranello struggled against porpoising, and probably they didn't overcome it 100%...

The fear of running into these pumping again, which makes the driver lose confidence and the car's performance, made the Ferrari engineers more cautious in validating the geometry of the SF-23 underfloor.

Mark Sutton / Motorsport Images

As can be seen in the image above, the only similar elements to what Red Bull has adopted are the presence of a central section which maximizes the airflow supply to the Venturi channels and the use of skids on the edges of the floor itself - again for the necessity to avoid the rubbing between road surface and floor.

The steps used by the RB19 are not there on the SF-23, which again gives a measure of how much at Ferrari they don't want to run the slightest risk of incurring in porpoising: with this goal in mind, they chose to voluntarily give up some performance to make the vehicle "safer". However, if we think back to FP3 in Monaco, in which Charles Leclerc asked the team to change the set-up due to the pumping in the Swimming Pool chicane, the technical frame of the SF-23 is complete, and shows a car that is very prone (more than the others) to porpoising. This is also why they cannot afford steps or other design artifices...

As proof of the extreme attention of the Maranello engineers towards this issue, we can see a "gem" in the same photo: many small stickers are distributed in the plank area... These are the so-called "pressure taps", a.k.a. pressure sensors that give information about the local pressure value generated by the airflow that invests the same area. Neither Mercedes nor Red Bull feature pressure taps near their plank.

Mercedes' floor: the improvements since 2022 are many and evident

To conclude the analysis of the three teams in question let's talk about the Mercedes W14, which presented itself in Monaco in a renewed bodywork compared to the first 5 races of this season.

Unknown / Motorsport Images

While last year's W13 had a basic floor configuration as the Ferrari SF-23, this year's W14 has some features that make it very similar to the Red Bull concept. For example, where on the RB19 there are 3 ramps to re-energize the airflow coming towards the diffuser, at Mercedes it was decided to adopt 2 of them; on the other hand, these introduce the airflow to such a diffuser whose ramp has no steps (as on the Ferrari). Even the Brackley team, therefore, cannot afford aggressive geometries without suffering from aerodynamic pumping...

From the same photo above you can also see how there are no skids on the floor edges, given that the Silver Arrows engineers decided to replace them using the metal right on the floor edges themselves (see the two lateral "stripes").

Unknown / Motorsport Images

Finally, from this other perspective it can be seen that even the strakes which divert the airflow arriving at the entire underfloor are placed in the same way as on the Red Bull RB19: the two outermost extend up to the maximum length allowed by the Technical Regulations, while the internal ones are roughly equidistant from each other.

Conclusion: in Formula 1 the devil is in the detail!

The aerodynamic principles that generate performance are known by all the teams, which in theory - and thanks to simulation tools - know perfectly what to do and what to avoid in the design phase. But the real difficulty lies in finding the right trade-off between sometimes divergent needs, in which favoring one area over another makes all the difference in the world.

The aerodynamic group of Milton Keynes has been well structured for a long time, so as to remain at the forefront even when the Technical Regulations upset the car concepts. While for Mercedes it is fair to say that the 2022 revolution took them by surprise (and they are still paying the consequences of it), at Ferrari I even see the absence of a technical direction to act as a guide in designing cars that are valid contenders against the above-mentioned rivals.