How F1’s cutting angles rocked the 2021 Championship
By the time the 2021 regulatory floor trim was announced, there were competing theories on how this would affect low-rake and high-rake cars, respectively. The fact that the two low-rake cars – Mercedes and its parent, the Aston Martin – appear to have significantly lost their competitiveness in the opening race at least suggests that the change fostered the high-rake concept popularized over the years. years by Red Bull and followed by most others. As such, the small adjustment designed to ease the strain on the rear Pirellis may have fundamentally changed the competitive order.
A diagonal line in the outer floor, starting 1800mm back from the front axle line at a point forward of the rear tire, 100mm on the inside, defines the cut. In addition, the various slots and holes that previously allowed to aerodynamically seal the ground and release the “tire squirt” air in front of the rear wheels have been prohibited. The vanes suspended from the rear diffuser (beyond 250mm outside the center line) were cut by 50mm and those attached to the rear brake duct were also heavily trimmed.
The angle of cut of the ground makes it possible to define the amount of negative pressure (and therefore of support) that it produces. It is multiplied by the surface of the soil. The Mercedes (and associated Racing Point / Aston) has always compensated for the lower rake by having more floor space from a longer wheelbase. Would the ground cut and associated changes hurt low rake cars more because the total loss of floor area would be greater (due to their longer wheelbases)? Or would the reduced tightness due to the prohibited slots force shorter wheelbase cars to lower their rake angles to prevent the airflow from stalling and thus losing more than low rake cars? With all teams required by regulations to keep their 2020 chassis as part of a cost-containment measure in the pandemic, they couldn’t design a car from scratch to meet flooring regulations.