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At the launch of the car McLaren was quite open about how it had arrived at a major new understanding too late in the car’s gestation to change it for the opening few races. The way the aerodynamic demands had changed around the rear of the floor thanks to the regulation tweak increasing the minimum height of the floor edge and diffuser there had led McLaren to its new understanding, one which was incorporated into the car with its Baku upgrade.

As Lando Norris commented recently: “The Baku upgrade was trying to add the philosophy in and making sure it worked and using that as the new baseline. [The Austria upgrade] is a performance step based on that Baku baseline.”

The performance steps each of those major upgrades made is startlingly clear on the qualifying performance graph above, using the cars of Red Bull, Ferrari, Aston Martin and Mercedes as a reference. Beginning the year as much as 1.8% off the pace, the McLaren was competing with AlphaTauri, Williams and Alfa Romeo. The Baku upgrade brought it to about 1% off the pace and competing in the midfield (apart from a tough weekend in Miami where it didn’t react well to the low-grip surface).

Since its Austria upgrade its deficit has been reducing from 0.4-0.1% of the pace, enough to see the car competing on level terms with Mercedes and Ferrari. These are spectacular gains by F1 terms.

What did those Baku and Austria updates bring to the car?

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Baku

This upgrade was all about a new floor which radically redistributed the loads through the length of the car. Although we have not yet seen any images of the McLaren underfloor, the inference from the changes to the floor edge implied that the tunnel shapes had been totally reconfigured.

The vortex generators and cut-outs were reprofiled. More of the floor edge’s plan area had been surrendered to create more powerful vortices and the rear of the floor edge, ahead of the rear tyre, had been completely redesigned, with a bigger pressure-releasing aperture and what McLaren described as more ‘floor structure strength’ implying a greater resistance to it being deformed by load.

Essentially it appeared that McLaren was seeking to induce more energy into the forward part of the underfloor, giving the diffuser a better quality of airflow to exploit.

Austria/Silverstone

The big update for Austria was again a reworking of the floor, but this time facilitated by a totally re-engineered cooling/sidepod arrangement.

This was essentially doing more of what the Baku upgrade did, ie making a more powerful airflow in the forward part of the underfloor, but this time by lifting up the whole forward part of the sidepod to create more volume there. Looking at the sidepod in profile, it would appear that the radiators have been re-sited further up in the car to make this possible.

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The underfloor is by far the most powerful determining factor in a car’s aerodynamic performance under this regulation set, but because it’s not usually visible the outer changes to sidepod and floor edge profiles are what we have to go on.

The sidepod shapes are aerodynamically significant but are of second-order compared to the underfloor and invariably their profiles are determined by what the aerodynamicists are trying to achieve with the underfloor.

That said, McLaren took the opportunity in reconfiguring the sidepod to enhance the ‘water slide’ feature on its upper surface.

The radiator inlets can only accept so much air and as the speed of the car increases so that capacity will be exceeded. The excess airflow at speed is channeled into the water slide and in that way prevented from disrupting the crucial airflow along the bodysides making its way to the coke bottle section and diffuser walls.

Instead it merges with that airflow in a much more controlled way at the base of the slide.

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For Silverstone a new front wing was added and the crucial detail change was how the metal brackets connecting the wing elements would appear to allow the outer edges of the footplate to bend downward under increased load at speed, increasing the gap (in yellow) between the slot gaps at the outboard edge. This will allow a greater outwash boost to the airflow as it travels down the sides of the car.

Taken together, the Baku and Austria upgrades represent two major steps of the same aerodynamic vision, one which has proved highly productive for McLaren.