Red Bull continues to dominate Formula 1 in 2024, while Mercedes is facing difficulties with the new ground effect regulations. For Mercedes, it seems like a repeat of the past two years, as demonstrated by their performance in Jeddah, which has fast corners. Lewis Hamilton has expressed concerns about the lack of confidence in the rear end of the car, which is a recurring issue. Despite Mercedes’ claims of fixing fundamental problems with the Mercedes W15, it appears that the issues from 2022 and 2023 are persisting. While Mercedes has made improvements to the car this year, they are still struggling to fully understand and address the challenges posed by the ground effect regulations. It is crucial for everyone in the team to reflect on these problems and acknowledge that there is still a lack of understanding in order to make necessary improvements.
The car performs well in low-speed corners, but it becomes unstable at the rear in high-speed corners, leading to a lack of driver confidence. This was particularly evident in Jeddah, a high-speed track where the car’s floor is pushed closer to the ground. As speed increases, the downforce produced by the car also increases exponentially. This puts immense aerodynamic load on the car, requiring proper support from the suspension system. The car’s ride height at 100km/h is 25mm at the front and 70mm at the rear, which, combined with the vertical stiffness, is a practical setup. However, relying solely on the vertical springs to support the load is not sufficient, as it would make the car too stiff in slower corners. In fact, the car would end up going below the ground or crashing into it at around 300km/h, which is undesirable for any F1 driver.
To ensure stability at high speeds, a front and rear central third support spring is added to the suspension system. While the side springs allow initial movement, the central spring comes into play to support the load in a straight line. However, it does not compress with the car’s roll, only providing support on the straights. The desired balance of the car varies between low and high speeds. In low-speed corners, more front-end grip is needed to respond to steering inputs, especially during turn-in. On the other hand, at high speeds, a more rearward balance is preferred to ensure rear-end stability. This is something that Hamilton has been requesting for over two years.
Achieving this balance requires generating a transient change in the aerodynamic center of pressure as the ride height decreases with increased speed. The front of the car needs to have roughly twice the vertical stiffness of the rear to handle the weight transfer during braking. By adjusting the aerodynamic center of pressure during the ride height change, the desired high-speed rear-end stability can be achieved. As the car reaches higher speeds, it experiences more downward force at the rear. However, the rapid growth of downforce also increases the risk of the car hitting the ground. To mitigate this, the design of the underfloor includes dedicated airflow separation areas that act as a “dimmer switch.” These areas allow for a controlled reduction in downforce, preventing the car from making contact with the ground. It is a delicate balance to maintain the desired aerodynamic center of pressure while preventing excessive downforce at high speeds.
Understanding the intricacies of the car’s floor design is crucial for Mercedes. Team principal Toto Wolff has emphasized the importance of simulations in predicting downforce levels in fast corners. However, there seems to be a discrepancy between the virtual world and the real world. Mercedes needs to determine why this is happening. The goal is to have a dimming effect on downforce as speed increases and the car gets closer to the ground. Conversely, as the car slows down or the ride height increases, the downforce should increase. This approach allows for maximum grip in slow speeds and better control at high speeds. Many teams, excluding Red Bull, struggle with grip and balance in either slow or fast corners. However, Mercedes is finding it challenging to strike the right compromise to optimize performance in both scenarios.