F1 | Mercedes: experiments in Australia to manage rebounds

The first two races of the season did not go as hoped at Mercedes, albeit for different reasons. In Bahrain the W15 seemed to have good potential, especially in the race, but over the long distance its potential was undermined by overheating problems arising from the use of an engine bonnet that was too closed. On the contrary, in Saudi Arabia the Stella disappointed not due to reliability problems, but rather due to the car's performance.

From the first free practice session it became clear that the car was suffering from bouncing, that is, that bouncing effect that mainly involves the rear, taking away the drivers' confidence. With setup interventions and various experiments, the team was able to improve the situation, but was never able to completely resolve the problem, which manifested itself particularly in the fast corners of the first sector.

Given the lack of aerodynamic load of the W15, well known to the drivers already on the eve of the season, the engineers tried to lower the car, as had already been seen in Bahrain, but this triggered those harmful bounces which weighed on performance. Although this behavior was evident with both drivers, it was Lewis Hamilton who suffered the most, who badly digested the dancing rear of his W15, never managing to find the right confidence.

It is no coincidence that the seven-time world champion also tried a more loaded wing in the third free practice session, which was then set aside when the advantages guaranteed by that specification did not exceed those given by the more relaxed version on the straights.

The reason why the drivers didn't feel comfortable was that those bounces continually changed the balance between the front and rear, an aspect which actually made the car rather unstable. On the contrary, the RB20, with its extremely stable aerodynamic platform, made that section its strong point throughout the weekend, recording higher speeds than its rivals.

“There is certainly data we are collecting from Jeddah. We are also looking at the race and test data in Bahrain, and we will propose a plan to understand how to approach free practice in Melbourne. But we will not just rely on what we did in Jeddah”, said Andrew Shovlin, engineer who takes care of all the work on the track, anticipating that in Melbourne the team will carry out experiments to understand which direction to go in to resolve the situation.

“There is a lot of work going on in the aerodynamic department and vehicle dynamics. We are trying to design some experiments which we hope will give us a positive direction for performance,” added the Briton.

George Russell, Mercedes F1 W15, Lewis Hamilton, Mercedes F1 W15

Photo by: Sam Bloxham / Motorsport Images

In Bahrain this problem emerged much less significantly, mainly because there were very few high-speed corners where a lot of downforce and aerodynamic support were needed. The shortcomings were seen in the change of direction 6-7, but in the rest of the track the W15 had given positive indications, in particular in the low speed corners, what seems to be one of the strong points of this car.

On the contrary, upon arriving in Saudi Arabia, problems emerged from the first laps in the high-speed curves that make up the first sector, where a car with great stability is needed, because it is not a dry curve, but rather a sequence and what is lost at the beginning is carried throughout the snake. Shovlin confirmed this is one of the key topics the team is looking at ahead of Australia.

“It's a combination of things. One of them is that the balance wasn't optimal. In those very fast corners, the walls aren't particularly far away. So, these are areas where the driver wants to have a lot of confidence, and a lot Drivers often experienced oversteer as they pushed the tires,” Shovlin said. Clearly Mercedes also chose a very unloaded rear wing which accentuated this aspect, although the problem goes far beyond a simple specification.

“And you can easily imagine how disconcerting this is for the drivers. This was a factor that influenced qualifying and the race. In qualifying we also suffered a bit from bouncing. In the race the problem eased. there is more fuel in the car. We go a little slower. But the problem seemed to have calmed down”, added the engineer, underlining how, clearly, in the first part of the race with more fuel on board this problem was alleviated, having to proceed at slower speeds.

George Russell, Mercedes F1 W15

Photo by: Steven Tee / Motorsport Images

“The main problem is that we don't have enough grip. That's one of the things we're working hard on this week, because Melbourne has corners of a similar nature. So we're working hard to try and understand why we don't seem to have the grip of some of the our closest rivals”.

Over the course of the weekend, Russell and Hamilton tried quite different setups, especially on the first day, where they also went in opposite directions to see what would work. One of the reasons was linked to the jumps in the first sector, but we also worked on other aspects, in the hope of being able to find the right balance between multiple elements.

“It's quite rare for the two cars to run with the same setup. We actually started with quite similar setups. The drivers gave us their feedback after the FP1 session. And at that point they went off in different directions,” Shovlin said .

Comparison of the rear wings of the Mercedes W15

Picture of: Giorgio Piola

“Partly [hanno provato assetti diversi] because they had complained about the bounce. So we tried to improve the situation. You can play with the ride height, you can play with the rigidity and things like that. Additionally, they were trying to fine-tune the balance across all speed ranges. For example, what is the car like at low speed? How does it behave at high speed?”.

After FP3, in which Hamilton tried something different, both cars converged towards the same direction, except for small changes linked to driver preferences, as normally happens. “We started to converge in the general direction. But you learn when you change things because you see the differences. If a car is modified, you can see how it performs from one race to the next.”

“We can also look at the overall performance of the two cars, but fundamentally the limits that we have in qualifying and in the race were essentially the same for both. So that tells us that the problem is not limited to a small camber angle or a spring or a bar here and there. It's something more fundamental that we need to delve into and understand.”