Mercedes technical director James Allison explained in detail why last year’s Mercedes F1 W11 was so good on all tracks and how they improved the already good title winning F1 W10.
After winning its sixth consecutive double title in 2019, Mercedes opted for a risky approach with a new car for 2020 to try to maintain a technological advantage over ever-closer rivals, and the car was significantly different from its predecessor in three important areas.
It is a front suspension, with a controversial DAS system, side safety structures like the ones first seen on Ferrari in 2017 with highly placed radiator openings and a rear suspension with radically positioned components for aerodynamic advantage and more stability.
The result was a car that was aerodynamically more efficient than its predecessor, better in qualifying and even better in slow corners, although they kept the longest wheelbase, identical since 2017.
“More downforce, more power, a little better balance between speed in one lap and speed in the race,” Allison commented on the key advantages of this year’s Mercedes over its predecessor for Auto Motor und Sport.
“The 2019 car was a great racing car, but it was a little harder to bring it to pole position [seven races without pole positions between Germany and the USA]. There are reasons for that. Also, it was hard to make the front end sharp enough . ”
The new rear suspension is a risky but worthy decision
“We started work on the new rear suspension in the April of 2019. We had a good idea about the torsional strength and characteristics of the new chassis, but when you change the position of the rod on the wheel carrier you also change the steering characteristics of the rear axle under load.”
“The old car  had an effect that destabilized the rear end because such a setup changed the toe angle under load. The new rod position reduced that effect and stabilized the rear end and drivers confirmed in testing that the rear end behavior was significant better. ”
Allison did not want to reveal whether the mechanical or aerodynamic side of the car benefited more from the rear suspension configuration change.
“I can’t tell you exactly how much we got in terms of aerodynamics, but enough to justify a new chrash test. With the new lower arm position, which is now connected to the safety structure behind the gearbox, we had to do a new chrash test.”
“To meet the rules, the test results had to be absolutely perfect. It took us a few tries. Structurally it was a difficult task because the wishbones were connected to a part of the gearbox that wasn’t very strong. So we had to strengthen the gearbox structure. But it paid off and solved handling issues. ”
Continuous progress in slow turns since 2017
Ever since they opted for a large wheelbase in 2017 to have the best possible aerodynamic efficiency, Mercedes has struggled with performance in slow corners, but year after year their car was getting better even in slow corners without losing too much in fast corners.
“The reduction in that weakness didn’t just happen last winter, we’ve been working on it since 2017,” Allison said.
“The 2017 Mercedes was impressive in fast corners, but a bit embarrassing in slow ones. It was a gradual process that brought us to where we are now. Already the 2019 car was very balanced in all types of corners in the race.”
“Downforce comes from aerodynamics, car weight, weight transfer, the way springs, stabilizers and shock absorbers work together. Aerodynamics never work the same way. It depends on the position of the car, how it leans in corners, how it leans back and forth, how much the wheels are turner, what is the distance from the ground. ”
“This matrix is the basis for the aero map. It shows how the downforce changes on the front and rear axles as the car moves through the corner. The art is to keep as much downforce as possible on the front and rear so that the tyres are happy, that neither the front the rear ones aren’t loaded too much. This has strengthened us in the slow turns where most of the time per lap is hidden. ”
“Where have we made compromises? At the highest contact pressure values in fast corners on tracks where the main aerodynamic load is on the front tyres. We don’t fly on them like we used to, but we’re still good enough.”
Development stopped after Spa
Mercedes had fewer improvement packages on its F1 W11 due to the shortened season and they were able to stop development earlier due to the big advantage they had.
“We stopped earlier than usual, because of the lockdown we lost seven weeks of work in the air tunnel. The season normally lasts 35 weeks so we had a one fifth less time,” he said.
“Our last aero development ended in mid-July, a month and a half earlier than usual. The latest improvements arrived at Spa. We brought a total of three upgrades, for Austria, Silverstone and the smallest one for Spa.”
MERCEDES F1 W11 SEASON STATS (17 RACES)
|Laps in the lead||801/1037|