Are Z-Shaped Floors the Way to Go in F1 2021?

But have we seen enough evidence from the first race to judge who is on the right track and who needs to think again?

On one hand, we have the conventional thinkers who have taken the new rules at full face value when it comes to dealing with the lost floor section.

Ferrari, Alfa Romeo, Haas, McLaren and Williams all have floors that are tapered towards the back as per the regulations. You’ve largely avoided having too much aerodynamic furniture on the edge of the floor to redirect the airflow as well.

Ferrari, Alfa Romeo, Haas, McLaren, Williams ground comparison

Photo by: Not in the credits

Meanwhile, Mercedes, Aston Martin, Red Bull and Alpha Tauri have a very different solution that has been available for their cars since testing, while Alpine joined their ranks at the first race of the season.

The five teams using this floor design created a Z-shaped edge for their floor, with a cutout about 200mm from where the floor tapers off. This has resulted in them giving up some of the total space available but giving them more flexibility in terms of the shape of the soil.

The yellow highlight indicates where the ground would have expanded to in 2020, while the dotted line indicates where the edge of the ground would be if the teams had followed the intent of the regulations.

Red Bull and Mercedes ground comparison

Photo by: Not in the credits

The teams that opted for this Z-shaped cutout have essentially returned to an edge of the floor that, as in previous years, runs parallel to the centerline of the vehicle. This suggests they weren’t happy with how the tapered edge affected the flow to the rear of the car.

But that doesn’t mean that they all went the same way. This picture makes it clear how much individuality can be associated with this design.

In particular, Red Bull has chosen to design the edge of its floor so that it has a much longer section that runs parallel to the center line of the car than is the case with Mercedes, for example.

The Z-shaped edge created also helps these teams create flow structures / eddies at a point on the ground where other flow structures could otherwise collapse or deviate from their intended path.

They further emphasize this by contouring the bottom and the fins mounted next to it, with Aston Martin perhaps being the most aggressive in that regard.

The slats (two rows in Aston Martin’s case – see main picture) are in a place on the floor where they certainly have an impact on how the airflow moves around the sidepod as well. However, your role in relation to the floor will be to realign the flow structures taking into account the straight edge of the floor.

This area of ​​the car is sure to be a hotbed of development this season as each team finds incremental gains from the interacting flow structures and tunes them accordingly.

Alpine, for example, has already made serious efforts in this regard as not only has it joined the four other teams that have already used the Z-shaped floor cutout in Bahrain, but also had to try a number of parts in combination with it.

Alpine A521 ground comparison

Photo by: Not in the credits

Alpine’s testing program shows where the team’s interests lie at this early stage of the season. Two key areas appear to be most ripe for development – the area where the ground begins to taper and the area in front of the rear tire.

In the case of Alpine, the soil tested in the previous season had neither the Z-shaped cutout nor the fins (V1 – blue). After the team had installed a floor with the cut-out, they tested two further solutions: In V2, not only were the two silver-colored slats mounted next to each other and offset from one another, but also two shorter triangular slats further downstream (red arrows).

However, it was decided to choose a slightly less aggressive solution, with only a single fin attached to the edge of the floor cutout (V3).

A number of solutions were also tested directly in front of the rear tire, discarding the single element strake used during the preseason test (V1), initially in favor of the trio of strakes that were used during the rear end of the preseason test were used (V2)) and then in a combination test with two other solutions (V3 & V4).

V3 and V4 both have four sections, albeit in a slightly different way, with V3 slitting only part of the surface, while V4 is made up of four individual bands.

Not a one-dimensional problem

However, as we saw from the pecking order restructuring in the opening races, it is not a one-size-fits-all equation as each team is at a different stage in the development cycle and has consumed its resources in different ways.

There’s also a tug-of-war over resources because while soil is by far the biggest change in regulations, there are other changes that could affect it and global vehicle performance.

For example, reducing the height of the ribbons could play a role in the difference between the low and high rake runners as it extends their proximity to the ground plane even further.

For the low-rake runners, they likely took advantage of the vorticity created in the past by the proximity of the strakes to the ground, which in turn generally contributed to the flow through the diffuser.

The overall design of the Mercedes diffuser is almost identical to 2020, except for the design of the brakes, the height of which has been reduced by 50mm to comply with the new rules.

McLaren has been the real outlier in this regard as they have used a clever interpretation of the regulations to maintain larger streaks in the center of the diffuser.

By connecting the strakes in the central 500mm of the car to the transition wall, the team was able to keep the larger strakes. However, this comes at a cost, as a single section needs to be maintained in this region.

This means that if you dragged a slice through this section, you wouldn’t have any breaks in the slice. This affects the overall shape of the boat stern and means the slots cannot have slots to optimize the flow around them.

It will therefore be interesting to see if there will be any changes in this area over the course of the season as the designers look for ways to optimize the aerodynamic transfer of flow structures from one area of ​​the car to another.