Stella about the problems of the 2018 chassis.
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But where had the McLaren engineers gone wrong? Stella explains, "Our 2017 model was a good foundation. We wanted to develop that further. In certain corners, we lost massively to the Red Bulletins in 2017. We wanted to turn off that, but have transferred this weakness to the new car. In retrospect, we've gone too far in some things and created some aerodynamic issues that put us in a dead end. "
The McLaren MCL33 could not maintain the contact pressure in curves over the entire course from turning to accelerating. To keep the downforce reasonably stable, McLaren made do with the mallet method. Bigger wings. They drove the air resistance upwards. And that cost top speed. The McLaren were among the slowest cars on the straight.
With the problem of fluctuating downforce McLaren was not alone. Stella pushes the phenomenon on the wider cars. "The larger front wheels produce greater turbulence than they did before 2017. The main task of aerodynamics today is to get a handle on this turbulence. The wider subsoil exacerbates the problem. Because it contributes more to the overall output than in the past. " According to Stella, this is also the secret of the top teams:" Anyone who manages to control the downforce better over the entire corner is in a different category. "
Like many other teams, McLaren realized that the simulation tools were no longer enough. "We have reached the limits of what a wind tunnel and CFD simulation can do," admits Stella. Therefore McLaren went from the GP Austria to use the first training on Friday as a test session. Parts of the development came to the car, some from the 3D printer, and the two MCL33s were stuffed with sensors to match the correlation between wind tunnel, CFD, and circuitMcLaren Senna in the driving report . "We turned every stone around to find out where the mistake lies," reveals Roberts.
McLaren changed the management during the summer and also changed the design office. At the same time, new measurement methods were developed in Woking to reduce the gap between laboratory and reality. "In fast corners our car was not so bad. Unfortunately there are less and less fast corners. Even Pouhon in Spa is now full without any problems, "summarizes Stella. "Our weakness was mostly in slow corners. And the processes in these curves are incredibly difficult to simulate in the wind tunnel and CFD. "
After the engineers realized that the MCL33 was caught in his concept, they tried to understand the bugs of the 2018 car so as not to run into the same trap in 2019. McLaren did a whole series of experiments to sort out the car's sore spots. Stella describes the difficulties: "These cars are incredibly complex. Even if you only want to test a new front brake ventilation, you need two months for design and production. That is why we have produced many test components in the rapid prototyping process. But often it is not a detail that is to blame but the interplay of many components. In order to get a better overall picture, we have changed our testing procedures. "
Simon Roberts is confident that the designers have understood all the problems. "It was a long process, not the one moment we said: That's exactly it. We could have incorporated some of the insights into the current car, but that would have put pressure on the weight of the car. Therefore, the pace of development in the second half of the season was rather slow. "Stella adds:" It's not that we missed the ideas. The concept itself had its limits. Many changes would not have worked. "