Why McLaren joined the F1 2021 Z-shaped floor trend

Rewind the clock to last year and the Woking-based team was actually the first to test a 2021 spec floor when they installed one on their MCL35 at the Belgian Grand Prix.

This enabled him to assess the aerodynamic chaos that the changes would cause to the rear of the car, which all teams had undoubtedly seen from their simulation work in CFD and in the wind tunnel when the changes were announced.

For the most part, these tests were done with immature solutions so as not to give competitors too much information upfront.

However, the floor McLaren used in this test formed the basis for the floor it had used for the first three rounds of that year, with the tapered floor edge in line with the intent of the new regulations.

By now, seven of his rivals had either started the season with the Z-shaped floor layout or had moved there during the first three races.

McLaren MCL35M ground comparison

Photo by: Giorgio Piola

And while eight teams have now followed a general trend, each of their solutions carries its own DNA as they take into account the aerodynamic decisions they made before and after the clipping.

McLaren, for example, added two angled fins in front of the neckline to enhance the desired effect. It only made a relatively short portion of its floor parallel to the center line of the car before it tapers back towards the rear tire.

After changes were made to the fins and brakes in front of the rear wheel in the first three races, no further changes have been made here, although these will certainly be optimized in the coming weeks.

Red Bull started its campaign with a Z-shaped floor, and while the middle portion of the floor has also been returned parallel to the center line of the car, this section is much larger than the McLaren arrangement.

A single strake dominates the ground in front of the cutout to create a flow structure at the same time, while two shorter, curved strakes have been added before the ground begins to taper towards the rear tire.

The teams that use a Z-shaped floor are essentially giving up some of the floor space available to them as they consider the shape of the floor to be more important in handling the airflow.

Mercedes tried to cover the edge of its floor as the car started so that the opposing teams would not have a head start to understand what it had done.

While the W12 has a Z-shaped cutout, it is more subtle than some of the other designs and is not combined with fins or brakes to create a more aggressive aerodynamic structure.

The shorter straight part of the floor leads to a much larger, tapered section in front of the rear tire which has also been raised and has a downward Gurney tab on the rear edge.

Mercedes was also much more aggressive in designing the bottom edge in front of the cutout. An undulating contour was used to affect the airflow that otherwise might have been affected by the previously allowed slots.

One would expect Aston Martin to have a very similar arrangement to Mercedes in many ways as both teams use a low rake setup. However, it faced the challenge in a very different way.

While Mercedes has largely focused its restoration efforts on determining performance based on the aerodynamic configuration that started the season, Aston Martin has instead arrived with a number of updated parts.

Aston Martin is already in the second generation of the Z-shaped floor design and has by far the most aggressive solution on the network. It has a long parallel section in the middle of the two small tapered sections made possible by a much larger cutout.

Also, to reinforce the aggressive bottom cutout, the team added two rows of ribs near the front of the cutout, both of which are made up of multiple ribs and arranged in a crescent shape.

It also has an aerodynamic structure that is the same size as Mercedes on the tapered section of the ground in front of the rear tire.

In an effort to improve the car’s global performance, and possibly increase the effectiveness of the floor cutting, the team accelerated new parts of the Portuguese Grand Prix but only had enough to show up in Lance Stroll’s car, forcing Vettel to wait until Spain waiting for his car to be fitted with them.

Upgrades included a redesigned front edge of the floor, adding an additional crest to the “wave section” while the scroll and Gurney-like extension above it were elongated and tapered to a point at the beginning of the floor cutout.

Meanwhile, at the rear end of the floor, an additional R-shaped scoop (red arrow below) has been added to the aerodynamic furniture mounted in front of the rear tire, and the shape of the diffuser has also been changed (circled).

Ferrari didn’t start the season with a Z-shaped cutout in the floor as it preferred the conical floor design intended by the rules and tested in 2020.

For the second race of the season, however, a new design was quickly introduced, in which the trio of fins was also discarded halfway as a by-product.

As seen with most of the teams following the Z-shaped cutout, Ferrari also combined it with an outwardly angled strip on the front corner to set up the flow structure.

To further improve performance, Ferrari in Portugal began testing another new solution at the edge of the ground in front of the rear tire, with the four-lamella configuration giving way to a seven-lamella arrangement instead.

In Portugal only one of these floors was available as the first steps in collecting real data were taken with the arrangement. With that or with a similar solution that is expected in the coming races.