McLaren test shows Ferrari concept was an inspiration for the MCL39

Extreme anti-dive and larger airbox

Starting from the frontal view, it’s possible to appreciate the first big evolution on the front suspension. It keeps the pull-rod scheme already adopted since 2022, but the placement of both the upper and the lower triangles was completely revised not only for mechanical reasons, but also to obtain a better deviation of the flow towards the body of the car. 

The rear arm of the upper triangle is now anchored to the chassis much lower and further back than on the MCL38: this design increases the distance between the two arms of the upper triangle enormously, producing a massive level of anti-dive, given that the rear arm of the upper triangle and the pull-rod are almost aligned (green arrow). 

Such a high level of anti-dive has a positive impact, as it prevents the nose from sinking under braking and provides a more stable behavior as the load is transferred to the front. At the same time, positioning the rear arm so low also has aerodynamic purposes, as it frees up a large area (between the two triangles) allowing the air to flow almost undisturbed towards the sidepod. 

Having a look at the pink arrow and circle, they both show how the steering arm has been placed differently than on the MCL38: while on last season’s car it was much flatter and its carbon cover was well-rounded, on the MCL39 it is more inclined as it gets closer to the chassis and its cover has a different shape throughout its entire length, mainly for aerodynamic purposes. Placed like this, in fact, it frees up a bigger area just behind the front wing so that air can be sucked into the Venturi channel. 

Moving on, it’s possible to see some more minor changes and tweaks around the halo and mirrors. 

For what concerns the first, there are now two vertical elements (very similar to a bulls’ horns) at the lateral foot of the halo, where it connects with the sidepods, with a design very similar to the one adopted on the Sauber in 2024. These two components, highlighted in yellow, have the main function to energize the flow (producing vortices) in an area where flow detachments are very common. 

The mirror supports have also been modified: the one closer to the driver is now much more edgy, with a vertical deflector connected to the horizontal support. At the same time, the very tiny carbon thread that connected the mirror to the sidepod has been moved slightly to the outside, connecting directly to a portiom of the tray placed above the cooling inlet (light blue arrows and circles). 

Last but not least, the airbox now has a much more rounded shape than the one adopted last year and its frontal area is also greater (purple arrows) proof that maybe another radiator has been moved upwards in the engine cover to have a bigger undercut. This change will definitely increase the level of drag a little bit but will for sure bring much more air to the PU radiators placed behind it. 

'SF-24 style' sidepods and engine cover

Moving now to the lateral view, it’s possible to appreciate some major changes also to the sidepod and engine cover design: starting from the cooling inlet (green area and arrows) it now has a tringular shape and extends not only in width but also in height, with a design very similar to that seen on both the SF-24 and the W15. The cooling inlet is characterized by a very narrow vertical part (mainly to generate low pressure and suck a lot of air in this area) and increases in width as you get closer to the horizontal tray above where the frontal section is larger, and thus the pressure is greater. This element is way different from the inlet seen on the MCL38, which was more squared and had a smaller extension to the lower portion of the sidepod.

The sidepod design as well is very similar to the SF-24 one, as the lower portion is very compact to create a bigger undercut and feeds a larger channel of air directed towards the rear diffuser and beam wing (purple line and arrow). Having a look at the upper portion, it features a very different design as well, with a linear trend throughout its length, without the curves shown in the MCL38 picture (light blue line and arrow). This design has the main goal of increasing the amount of air pushed in the gap between the rear tyre and the floor, feeding the channel underneath the car and generating more downforce from the diffuser as a consequence. 

Having a closer look at the engine cover in the upper section of the picture, it also features a much more linear trend towards the beam wing than the previous version adopted on the MCL38: the curvature of the two "cannons" is much less pronounced than on the previous car, so much so that they seem like very long "trays" that have the aim of pushing the air towards the beam wing without affecting the flow directed towards the rear wing (red arrows and lines). This design recalls the engine cover of the SF-24 as well. 

Different cover on the upper triangle 

The last picture allows us to spot some more details and changes on the front arm of the upper triangle (green arrow and circle): the carbon cover has a more rounded and linear shape as it connects to the wheel hub, whereas the previous had a more inclined cover, probably to push the front tyre wake outside as well, preventing it from being sucked underneath the car and producing harmful effects on downforce generation. 

The light blue lines and arrows also show some further changes to the edge of the sidepod, which has a more linear curve along the entire perimeter and the undercut line now tends to push the air upward rather than towards the outside as happened with the previous design on the MCL38. 

Last but not least, it’s important to underline that the front and rear wings have not been analysed because they’re the same adopted during last season; in specific, the front wing is the same introduced in Austin and the rear wing is the same used in Brazil and Abu Dhabi 2024.

Having had a look at all the new components, they look extreme in some ways but also in line with what have been McLaren’s philosophy during the last two seasons. The goal is clearly to increase the amount of downforce generated by the Venturi channels, to obtain more efficiency from the bodywork (in fact efficiency was one of the main weaknesses of the MCL38) and thus make the car competitive also on low-downforce circuits. 

After last year’s success in the Constructors’ Championship, the team will be keen to continue their positive momentum in order to get even more victories under their belt. The competition with Ferrari’s SF-25 and Red Bull’s RB21 will surely be very close, but only the tests in Barahin in a couple weeks and the first Grand Prix in Melbourne will give us a clearer idea on which car is the fastest.