Mark Hughes looks at Mercedes’ drop in performance from Sao Paulo – where George Russell clinched his first and only win of the season – to Abu Dhabi, where Russell finished fifth and Hamilton failed to finish. Giorgio Piola provides technical illustrations.
Mercedes’ recent return to form was nullified in the final race of the season in Abu Dhabi. Just seven days after their one-two in Brazil, they were definitely only the third fastest team around the Yas Marina circuit.
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After their significant bottom and wing upgrade in Austin, along with a revised wing and some significant weight savings, there was a marked shift in the W13’s competitiveness. But that was on routes — Austin, Mexico City and Sao Paulo — that don’t unduly penalize higher drag.
At Abu Dhabi, the long flat-out sections of Sector 1 and the chicane-punctuated flat-out sections between Turns 5 and 9 mean that low drag is a key part of the equation for being competitive there. From its performance patterns over the season it can be concluded that the W13 is a significantly more sluggish car than the Red Bull. In Abu Dhabi this hurt a lot more than the previous three track layouts.
This affected the team’s strategic decisions, as explained by Track Engineering Manager Andrew Shovlin. “After looking at the timesheets for FP3 we came to the conclusion that whatever we did, we would probably have two Red Bulls ahead of us. We didn’t expect to be that far behind the Ferraris – that was a little disappointing. But the fact that we knew we had the Red Bulls ahead meant we didn’t make any decisions based on qualifying. Everything was for the race.”
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In the practice sessions Lewis Hamilton and George Russell had both tried a reduced flap angle rear wing which reduced the straight line speed deficit over the Red Bull and low wing Ferrari but proved slower over the lap due to oversteering through the tighter corners of the last sector.
Given that they were expecting to qualify behind Red Bull anyway and that the race should be well balanced between a one and two stops, Mercedes opted to run the larger wing to protect the tyres, even if it did their car made less raceable wheel-to-wheel because of its vulnerability at the end of the straight.
Another mystery that presents the layout of the Yas Marina Circuit has probably hurt Mercedes more than the others. A certain tire management is necessary here, even during a qualifying lap. When the available grip is fully utilized through the long, fast corners of sector 1, the rear tires tend to overheat for the corners of sector 3.
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To make matters worse, it’s difficult to get the front tires up to temperature early in the lap without overheating the rear tires. This poses a particular problem for the Mercedes W13, which requires a particularly aggressive outlap to bring the front tires up to temperature. This is a disadvantage of the positive characteristic that the car does not overload the front tires in the race.
Much of the thermal management of the front tires comes from the brake pipe assemblies inside the wheel. That of the Mercedes is very sophisticated, as we discussed here recently. We can see the difference between the maximum brake cooling arrangement used in Mexico’s thin atmosphere and that in Abu Dhabi.
“We don’t seem to be changing that [ducting] as much as some,” says Shovlin. “Generally we try to keep the rubber on the cooler side as that allows it to last a bit longer and keeps the pressure from getting too high. Others try to bring in more temperature than we do.”
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The more the brake is cooled, the more heat is transferred to the rims and tires. In Mexico, full priority had to be given to brake cooling, which is extremely marginal there. So front tire cooling had to be less important there, but around Abu Dhabi tire cooling came back to the fore as an important part of the car’s good tire usage in the race.
As with the choice of wing, it emphasized how much Mercedes’ decisions were based on race day performance rather than qualifying.