Last season proved that porpoising isn’t the only side effect of the new rules and technical regulations. For several weeks, the FIA has been frantically looking for solutions that improve the visibility and safety of racing in the rain, especially when wet tires are used. Unfortunately, as one team’s engineers put it, generating a lot of concentrated spray “is in the DNA of new cars.”
Driving on wet tires was still very limited. Without forgetting that the teams have always favored the use of intermediates. The extreme wet compound was always the most criticised, especially by Max Verstappen and Sebastian Vettel, and Pirelli is aware of having to improve it. “On the wet we need to improve especially the warm-up phase as well as the performance” for tires that have often proved to be actually much slower than the intermediate ‘green’ ones. This is the main reason for the choice by the teams to mainly use intermediates rather than wet tyres.
Why the new regulations have worsened visibility on a wet track
However, we must not forget the visibility issue, caused by the large amount of spray generated behind the cars and certainly worsened by the new aerodynamic regulations. The full wet Pirelli tire is capable of draining up to 85 liters of water per second at a speed of 300 km/h. Intermediate tires under the same conditions can only extract 30 liters. This gives us respectively 340 and 120 liters of water thrown into the air in just one second. This difference explains, in part, why visibility is so much better when cars run on intermediate tyres, as explained by Daniel Bialy for formu1a.uno.
This must be linked to a response connected to the new aerodynamic principles, the objective of which was to limit the effects of dirty air on the car following behind. This was made possible by two things: keeping the flow close to the car and throwing it high just behind the rear wing. Both phenomena are clearly seen in the photos shared by Ferrari from Pirelli’s post-season tire tests at the Fiorano circuit in December.
In the photo above, you can clearly see how effective the covers on the front wheels are (1), since dirty air is not allowed to spread to the sides, avoiding the dreaded outwash effect. The ban on the expulsion of hot air from the braking system through the rim further contributes in this view, also ensuring that all disturbances do not disperse in all directions. Then, the arrangement of the rear wing, the beam wing and the diffuser (3) causes the airflow behind the car to be directed more upwards at a shorter distance from the rear of the car.
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The spray visible in the first photo also shows that the Ferrari’s side sections, while wide, don’t generate as much drag, rather they help reduce it. They move (2) the flow of dirty air away from the rear wheel, to remove a large part of the resistance since the wheels are largely responsible for drag.
The diffuser is the main problem, not so much the water raised by the tyres
As ex-McLaren aerodynamicist Patryk Sokolowski explained for formu1a.uno, the geometry of the diffuser is crucial for controlling the jet of water following the car. In previous years, the upper edge of the diffuser was much lower, which caused the air coming out of it to the sides (4) to expand along the Y axis. From this point of view, on previous cars the diffuser had been lengthened at most in this plan.
The new regulations have made the upper part of the diffuser much higher, which causes an expansion not so much laterally but upwards. Lateral expansion is further limited by the need to control tire trail (6), with teams not using the maximum legal width of the diffuser, leaving this area primarily to manage the dirty air generated by the rear wheels.
All these elements put together make the jet of spray thrown behind the car higher and more condensed. As a result, the impact on cars’ visibility is greater as the spray stays in the air longer. This effect was also observed during testing on the Fiorano track.
That’s why the FIA is looking at ways to improve visibility in the rain. However, the solutions proposed so far have met with opposition from all teams. Even the much talked about cover flaps would not completely solve the problem, precisely because the diffuser is the main component from which the spray that reduces visibility is generated. So not so much water raised by the tires. “To try and improve visibility, the biggest challenge is to determine the amount of spray caused by the diffuser versus the amount caused by the rear wheels.” – said Nikolas Tombazis, head of the FIA technical department.
Certainly, the cover flaps would improve the situation and this is why the Federation is pushing for their introduction in the 2024 world championship. With the aim of avoiding another Spa situation, the which was the lowest point of modern Formula 1. “Not competing is unacceptable because we have so many spectators, both watching from home, on the track with purchased tickets, not forgetting the teams traveling around the world.” – Nikolas Tombazis added.
However, the situation is unlikely to change drastically, because the condensed spray is even more in the DNA of the new ground effect cars. For a total resolution of the problem it will be necessary to wait at least until 2026 when a new generation of cars will be introduced.