Tech Analysis | Stella: "This is a bit of a surprise to us how competitive the MCL39 is"

Different set-ups during FP1 

During the Australian Grand Prix weekend, McLaren used FP1 to try two different aerodynamic configurations and understand which one would have worked better for the Albert Park layout. For this reason, different rear wings and beam wings were fitted on Norris’s and Piastri’s cars: as highlighted in the drawing below, Norris tested the lower downforce set-up, while Piastri the medium downforce one. 

The package adopted on Norris’s car included a low downforce rear wing and a double element beam wing. As for the rear wing, it was characterised by a main profile with a slight spoon in the central portion of the wing, while the rest of the leading edge was characterised by a straight trend to minimise the drag produced by this profile, thus improving the top speed of the MCL39 on the long straights of the Australian circuit.

The DRS flap, on the other hand, was characterised by a much greater chord, in order to generate a greater "DRS" effect, i.e., to ensure that much more air passed through this "window" when the mobile flap was activated, providing excellent efficiency even with the wing open (red arrow, right side of the drawing).

To compensate for a part of the downforce lost due to the adoption of this very unloaded rear wing, the team decided to adopt a double-element beam wing: the lower element was characterised by a "drop" profile, with an increased chord in its central portion (about 3/4) of its length and with a smaller chord at the attachment to the endplate to favour the outwash effect.

The upper element, instead, has a "bridge" shape, very similar to beam wing designs that appeared on both Ferrari and Mercedes over the past few years. This element, in fact, was characterised by a very reduced chord and serves to create a low pressure area that makes the rear wing and the diffuser work at their best (blue arrow, right side of the drawing).

As for the spec adopted on Piastri's car, it included a medium-load rear wing and a single-element beam wing. Starting from the rear wing, it was characterised by a DRS flap identical to the one adopted on Norris's car, with a different design instead of the mainplane, which was characterised by a "spoon" shape with a much more pronounced V-shape in the central portion.

In fact, the chord of the airfoil in this section was much greater than the previous version in order to generate a higher level of downforce and also the lateral portions of the leading edge had a much more curvilinear trend connecting to the endplates compared to the previously described version, precisely to generate more load (red arrow, left hand side of the drawing).

At the same time, however, to reduce the drag produced, the team decided to use a single-element beam wing on Piastri's car, having an identical shape to the lower element of the beam wing seen on Norris’ MCL39, in order to have a good top speed (blue arrow, left hand side of the drawing).

After all the tests and comparisons made during the first free practice session of Friday, the team decided to adopt Piastri’s rear wing and beam wing spec on both cars from FP2 onwards, conscious also that Sunday’s race would have probably been wet. 

From the second practice onwards, the MCL39 looked very well balanced and was particularly impressive during second practice race pace simulations. Despite this, especially during FP2 and FP3 the battle with the other top teams was much closer, with 7 drivers all within a few tenths. However, during qualifying, the Woking based team took a step forward in terms of speed and set lap times that were unattainable for everyone, with Norris and Piastri 0,350s ahead of Verstappen.

The pace shown during the race was even stronger, as the MCL39 seemed the only car that instead of degrading the tyres, was able to extract more and more performance as laps went by. Particularly effective was that, at lap 34, when the safety car came out due to Alonso’s crash, the Norris-Piastri tandem were about 16 seconds ahead Max Verstappen and this gap was built in less than 17 laps, which translates in almost a second per lap faster than the Dutch driver.

Moreover, the car was competitive in every condition, both wet or dry and particularly impressive was the second restart behind the safety car, when Norris and Piastri with the hard tyre were able to comfortably open a gap on Verstappen in P3 with the medium compound despite the tyre disadvantage. 

Stella's words are proof of the MCL39 competitivness 

But where does this great advantage over the rest of the field come from? 

The answer needs to be searched in Andrea Stella’s words after the race, which explain the MCL39 in a very simple and direct way: “I think I've said already that last year when it was about deciding what kind of approach we should have had for the 2025 car, considering that the 2024, after the Miami upgrade, looked pretty competitive.

"We wanted to be ambitious because we saw that the level of competitiveness we were receiving from Ferrari, Mercedes, Red Bull, was so strong that I think there was no room for complacency. So we gave ourselves some technical targets, which had to do like always with aerodynamic efficiency, but also we wanted to improve from a mechanical point of view and the interaction with the tyres.

"And I think today, once again, we saw that the car interacts with the tyres very well, because in the first stint, we were able to open a gap to the other cars which I don't think is the car itself only, [but it] is also how gentle the car is on the tyres. So I think in a way this is a little bit of a surprise for us as to how competitive the car is but let's say it's a surprise in terms of the extent, it's not a surprise in terms of the objectives.

"The car seems to have achieved some of the objectives that we gave ourselves. The extent, in fairness, we will see more over the next races and this will give us a better understanding of the competitiveness order, but also, still I think this weekend for instance we have not seen Ferrari. I think they are actually not far from us. So we will see more.” 

These words underline what has been the guiding principle in the development of the car over the course of these three years under the ground-effect regulations: finding ever greater efficiency, which is not to be understood as less drag generated by the car, but rather as the ratio between the load produced and the level of drag.

The objective of the team led by Stella, in fact, has always been to make the car faster both in the corners and down the straights, increasing both the level of downforce generated and its top speed. This approach has thus allowed the Woking based team to have an extremely fast and competitive car in almost every condition, thanks to the high level of downforce, combined with the suspension system, that allowed the car to warm up the tyres even at low temperatures.

This is exactly what scares all competitors: the 2023 RB19 was a very efficient car as well, but it lacked pace in the slow speed and on bumpy layouts compared to their rivals, while the MCL39 seems to be extremely balanced and quick in every condition and on two opposite layouts like Melbourne and Bahrain.

The gap to Ferrari, Red Bull and Mercedes isn’t probably the one we saw during this weekend, but it’s clear that McLaren is able to make their car work in a better way than other teams do, easily extracting its full potential. 

The next two races, which will take place on permanent and more indicative circuits like Shanghai and Suzuka, will give us a clearer portrait of the hierarchies between the top teams. If McLaren show this level of dominance also in the next few events, it’ll probably be better for other teams to directly switch their focus to the new 2026 cars.