Analysis of the new F1 aero rules: three tenths slower per kilometre. Analysis of the new F1 aero rules.

The FIA’s aerodynamic restrictions are having an effect. The new Pirelli tyres also play a role. After four races, the 2021 Formula 1 cars are losing an average of three tenths per kilometre to their predecessors.

There will probably be no new records this year. At least not in the first half of the season. For the first time since 2017, Formula 1 has become slower again. The FIA’s measures to slow down the cars to protect the Pirelli tyres from overloading are having an effect. The cars are on average three tenths slower per kilometre on the qualifying lap than last year. On the fastest race lap, the delta is somewhat smaller.

The length of the race track and, to a certain extent, the conditions determine the absolute value. In Bahrain, the gap to pole position was 1.733 seconds. That makes 0.320 seconds per kilometre. In Imola, the 2021 cars came closest to the 2020 qualifying best time. Lewis Hamilton was only 0.802 minutes slower than Valtteri Bottas six months earlier. In kilometre terms, that meant a difference of just 0.164 seconds.

Portimao was then more back to normal. 1.696 seconds per lap, 0.364 seconds per kilometre. The ultimate test of Barcelona fitted into the picture. Hamilton missed his 2020 best time by 1.157 seconds, resulting in a deficit of 0.247 seconds per kilometre. However, the Circuit de Catalunya was 20 metres longer this year, but the new line through turn 10 was also 35 km/h faster. That may have added a tenth in favour of the current version.

Three factors for lost time
There is only one explanation for the runaway at Imola. Imola was new territory for everyone last autumn. There was only one free practice session before qualifying. This time, drivers and engineers were able to get to grips with the peculiarities of the track for over three hours before qualifying and fine-tune the set-up of the cars accordingly.

In the case of Barcelona, it must be mentioned that the 2020 Spanish GP took place early in the year and the cars were not yet at the latest stage of development, in contrast to the late races Portimao, Imola and Bahrain.

The lost time is due to three factors that are difficult to separate. Firstly, there are the new Pirelli tyres with their more stable construction. Originally, the teams assumed a time loss of one second. This is probably exaggerated.

Pirelli allows 1.5 to two PSI lower tyre pressures. The increased contact area compensates for part of the deficit. Since the front tyre has a different shape, it also has an influence on the aerodynamics. And this is disturbed for other reasons.

Downforce loss not yet compensated
The biggest time killer is the sloping floor in front of the rear wheels. There is no substitute for aerodynamic surface. And the cut changes the flow around the rear wheels and makes the diffuser more vulnerable to the turbulence produced by the rear tyres. These have a big influence on the flow to the diffuser.

By shortening the fins on the rear brake vents and the vertical plates in the diffuser, the regulators made life even more difficult for the engineers. They helped to steer the flow into orderly channels.

Over the winter, the cars became another six kilograms heavier. That’s simple physics. That’s two tenths. In return, the engines have gained in power. One could outweigh the other.

More effort for the extra point
In theory, the cut in aerodynamics should cost ten per cent downforce. But according to Pirelli, the engineers have already regained four to six per cent of that. McLaren technical director James Key put the time loss of the first version at around one second. That’s a long way off again. And yet it doesn’t seem so easy to make up the lost time. The cars are only getting faster in triple steps.

That can have many reasons. Either the measures were so severe that the engineers are limited in their correction possibilities. Or the teams no longer have the time to do normal development work.

So far, only Haas has gone all the way to 2022, but all the others have already branched off into working groups that are working on the 2022 car. And in times of budget caps and limited wind tunnel time, they are missing on the 2021 model.

By the way, the differences are smaller when comparing the fastest race laps. If you exclude Imola, but there the rain on Sunday did not create comparable conditions. In Portimao, the fastest race lap this year was 1.115 seconds higher than last year, in Bahrain only 0.076 seconds. And Barcelona was the tiniest of 0.034 seconds faster. The reason for this is obvious. This year, the two world championship opponents invest much more effort in the extra point. That makes for faster laps.