McLaren’s James Key breaks down notable differences between the team’s MCL35M and its predecessor from the 2020 F1 season.
Chief among these differences, Key writes in the new blogpost of McLaren, is the switch to Mercedes power in the MCL35M. He explains that the change meant the F1 team had to develop new ‘chassis; gearbox; and fuel, hydraulic, electrical and cooling systems’, as they built the new car.
The team had to make these changes while still working within regulations restricting development, Key also notes. “The power unit is a fundamental part of a car’s architecture and because many of the Mercedes components, such as the engine and energy store, have different geometries compared to what we used last year, we effectively had to redesign the whole car,” he started.
“But we had to do this while adhering to the homologation rules, which meant carrying over elements from last year where possible and adapting what we already had to fit the power unit in. Nevertheless, the switch to Mercedes power has resulted in a new chassis; gearbox; and fuel, hydraulic, electrical and cooling systems.
“Even the wheelbase has changed: we’ve had to extend it slightly because the gearbox bell housing is longer to accommodate the Mercedes engine,” Key writes, adding of the token rules: “Although we spent our development tokens on the power unit installation, it’s not fully optimised because of the rules around homologation.
“We would have done it differently were it not for the restrictions put in place for 2021,” Key wrote. The Brit says, writing of the changes they did make to accommodate the new PU, that they could have – and would have – made more changes to the car if the regulations had permitted it.
“When modifying the chassis, we worked very closely with the FIA to ensure we were only changing what we needed to, but this meant we couldn’t exploit the chassis change as much as we would have liked in the pursuit of performance.
“Although we spent our development tokens on the power unit installation, it’s not fully optimized because of the rules around homologation. We would have done it differently were it not for the restrictions put in place for 2021,” Key says.
McLaren ultimately spent all of their development tokens on fitting the new F1 engine, but continued to develop the car aerodynamically, with aerodynamic design one unrestricted area. Key says that each step they took was either to fit the new engine, or to improve the downforce produced by the car by way of building 2020’s design philosophy.
“This year’s bodywork is based on very similar principles to last year and I don’t think this will change during the season because it’s something that’s largely defined when you’re in the throes of defining the car architecture,” says Key, who also made note of regulation changes pertaining to the floor of the car.
Key says that attempting to find downforce lost as a result of these changes has been challenging. “The aerodynamic regulation changes this year – which include narrowing the floor ahead of the rear tyre by 10 cm, outlawing slots in the floor, shortening winglets on the lower half of the rear brake ducts by 4 cm and clipping diffuser fences by 5 cm – are really a safety measure aimed at reigning in the performance of the cars by cutting downforce somewhere in the region of 10%.
“Although the changes seem very subtle, they have a considerable impact. We’ve been trying to claw back the downforce lost and it’s been a real challenge. It’s required fresh thinking because the geometries imposed by the regulations are unique and not something we’ve encountered in the past.
“And while the changes take downforce away from the rear, it forces you to take some off the front to rebalance the car, so there’s been a global reduction in downforce,” Key explains, adding: “On the other hand, most of the aerodynamic surfaces are free to develop: things like bargeboards, and the front and rear wings.
“We’ve been working hard on these areas and will continue to do so throughout the season. There’s plenty of scope to make improvements – to enhance our strengths and address any weakness,” says Key, who finally makes note of the changes to 2021’s tyres – changes implemented, he says, because weaker constructions were tested by high-speed circuits.
Here’s videos and photos from McLaren filming day
Here’s full details on McLaren MCL35M launch
Here’s all of the power unit fire-up plus launch dates