McLaren: What has changed on the MCL35M?

McLaren

McLaren: What has changed on the MCL35M?

We look at how McLaren has adapted its car for the new season

Ewan Gale

Sunday 21 February 2021 09:15

McLaren's launch of its MCL35M provided the first glimpse of how Formula 1's aerodynamic reforms for 2021 will look on what is essentially old machinery.

Given the delay until next season of more wide-sweeping regulations changes, the rules for this year were tweaked to halt the year-on-year progression of downforce attained by teams, with safety the main factor in the decision.

In addition to the technical directives changing the aesthetic of the car, McLaren has had the added complication of switching engine supplier from Renault to Mercedes between seasons.

So where does this season's McLaren differ from last year's iteration?

Floor assembly

The major aerodynamic change that we can expect to see on all cars this season is a redesign to the floor structure in order to cut the downforce levels achieved around the back-end of the cars.

As seen on the MCL35M, the intricacies of the previous floor design are gone, with a much more straightforward, flat surface with no cut-outs in the physical structure.

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The rear section of the floor is also inverted towards the inside of the rear wheel, changing the airflow around the rear of the car.

This seems a fairly basic design, with the team potentially keeping its cards close to its chest as it was the first to reveal. It is unlikely, however, wholesale changes will take place ahead of the first race.

Sidepods and engine cover

With the Mercedes power unit integrated into a car that was essentially designed to house a Renault engine, necessary changes have had to be made despite last season's car homologation.

Technical director James Key has explained that the team has altered numerous aspects of the car within the technical regulations to integrate the new engine.

"[We had to] make the changes we needed to the homologated parts so that was to change the chassis, which of course has to change with a new engine and the energy store, aspects of the gearbox for packaging purposes and after that it is all identical to last year," he explained.

Whilst all of these changes are hidden underneath the slin of the MCL35M, there are noticeable changes to the packaging around the new power unit.

The sidepods have been pinched the lower down the bodywork you go, with a widening effect higher up the structure creating a helix-shaped, hourglass-figure look, akin to the Mercedes W11's configuration at the tail-end of last year.

Similarities can be seen in the packaging of the engine cover and sidepods of the W11 and MCL35M

Also adorning the side of the new McLaren are cooling 'gills' not seen on last year's car.

This is potentially a derivative of the split-turbo concept of power unit Mercedes run compared to the more traditional-set engine layout of the Renault, with the different philosophies likely causing different cooling solutions.

Gills are also featured on the Racing Point RP20 of last season, although not on the Williams FW43 - the other Mercedes-powered car on the grid.

Cooling gills can be seen just below the beginning of the halo structure on last year's RP20

Wheelbase

A very subtle change, but this season's MCL35M has shifted the wheelbase slightly compared to its predecessor due to a longer gearbox bell housing accommodating the new engine.

Front-end package

Left-hand side shows 2020 car at launch, right-hand side depicts MCL35M

Much of the front end of the new McLaren has been left unchanged from how the car finished last season due to the homologation deadline mid-way through.

The developments made by the team prior to the Eifel Grand Prix have remained on the car, with the differences made clear between the two launch specifications of both the MCL35 and the MCL35M.

The brake ducts have a different shape to accommodate both aerodynamic and cooling efficiency, whilst the nose structure was changed to alter the airflow underneath the car.

Looking further back, the airbox has been modified slightly to allow for a different flow of air to aid with the cooling of the new Mercedes engine, much as can be seen with the addition of the sidepod gills.

The aerodynamic updates to the rear wing end-plate will no doubt evolve over the early part of the season as the team attempts to claw back some of the downforce lost through the new directives.

It is important to note the front wing assembly, the bargeboard layout and rear wing will all likely be run in different specifications come pre-season testing in Bahrain in early March.