Tech Analysis | Will Red Bull be able to make the updated RB21 work in Melbourne?

Very similar but still different to the RB20

As the RB21 hit track in Bahrain, it immediately looked very similar to the RB20 from an exterior point of view, even if some small changes were noticeable. The goal of Red Bull’s engineers during the winter was to keep the positive aspects of the RB20, while improving the weaknesses that made the car slower during the second half of last season. 

As it was possible to appreciate on track, last year’s car was very good in high-speed corners and smooth asphalts, mainly due to the very stiff suspension system that allowed the aerodynamic platform to work at its bets at low ride heights.

Despite this strength, the RB20 had a very small working window, meaning that engineers needed to test a lot of different set-ups before finding the one that made the car express its peak performance. The clear example was 2024 Qatar Grand Prix weekend, where Red Bull struggled with set-up on both Friday and Saturday, but after making loads of tests and using the Sprint as a test bench, they were able to find the right set-up that allowed Verstappen to excell both in qualifying and during the race. 

For this season, the technical department led by Pierre Waché set as the main goal to build an overall rounder car, making it possible for the engineers to find the right set-up and be competitive also on difficult weekends or on less favourable layouts. As a consequence, they “reevaluated all the concepts of the car. We modified most of the stuff that is maybe not as visible as the older car – the concepts overall stay the same – but plenty of stuff has changed underneath and inside the car that, in terms of cooling, suspension, aero package, everything has changed to achieve the characteristics we like.” he told PlanetF1.com.

These words underline the great ‘invisible’ work done by the team during the winter, even though some changes, especially in the diffuser and Venturi channel area were visible since the first day of testing. Having a look at the drawing below, it’s possible to appreciate an evolution of the shape of the tail end on the keel of the diffuser in line with what was seen last season (orange arrow). The tail end of the boat, in fact, has a sharper and more vertical shape, with the keel positioned at a lower height from the ground than the version adopted last year. This design is very similar to the ones adopted by Ferrari and Mercedes during last year, after experiencing porpoising issues. 

This solution is, in theory, less profitable in terms of peak downforce produced, but it helped the engineers set up the car and stabilize the diffuser at different ride heights and speeds, avoiding instability especially at high yaw angles i.e., slow corners, exactly where Red Bull suffered last season. 

From this same drawing, a new beam wing can be appreciated as well: as highlighted by the blue arrows, it is a two-element beam wing. The lower profile is characterised by a very high chord for almost the entire length of the profile, with a reduction in the chord and a big angle at the connections with the endplate and the rear anti-impact structure.

The adoption of this angle means that the lower element of the beam wing represents a sort of "addition" to the top wall of the diffuser, improving flow extraction and working in synergy with it. As for the upper element of the beam wing, it has an almost flat shape, with a much lower chord than the element below and as main function to produce a lower level of downforce in favour of top speed.

This design also generates a low pressure area, improving the performance of the rear wing, beam wing and diffuser as a whole, making the rear of the car much more stable in traction zones where rear downforce is also needed.

This change, matched with other ‘non-visible’ changes to the Venturi channels underneath the car, made the RB21 look competitive during the first day of testing especially in Verstappen’s hands: the Dutch World Champion looked pretty comfortable, as the car was very clean and precise. An aspect that was already possible to appreciate during the first day of testing was that the car was extremely stiff, having a good balance through the fast 12-13 and 6-7. 

With the second day compromised by the rain, the third day was a proper showdown between the top teams, where they showed their cars’ "real performance." Red Bull, however, adopted a different strategy, bringing ahead of times some updates that were scheduled for Melbourne, in order to have a clear comparison with the “base” car spec that they'd run the two days before. 

The new components included a completely revised front wing and a new floor (whose changes laid underneath the car, making it almost impossible to spot them). For what concerns the new front wing, it represented a radical shift compared to the first version, proof that team was looking for a major change.

As highlighted in the drawing below, the first big change concerned the nose of the car: while in the first version adopted on day 1 and 2 of testing it connected directly to the mainplane and had an almost flat trend throughout its length, the new solution connected to the second element and had a much rounder profile (light blue lines and arrows).

Moreover, the width of the nose also changed, as highlighted by the green arrows: while the old version narrows as it gets closer to the mainplane, the new version is much wider and thicker, probably to provide greater support (in terms of stress) to the wing itself and avoid excessive flexing. As a direct consequence, the new version featured a gap between the mainplane and the second element, which can be helpful to increase the local downforce produced by the front wing itself.

Furthermore, the new mainplane featured a much flatter profile in the central portion (just below the new nose) with a much more pronounced (almost squared) slope to the lateral profile, mainly to help pushing the air towards the Venturi inlets behind (orange lines and arrows). 

Last but not least, the connection of the top two profiles to the endplate has also changed, as shown in the detailed drawing below. While the version used during the first and second day of testing featured an inclined airfoil profile that was connected to the endplate by a simple metallic support, the new version is characterised by a much more complex connection that provides benefits from an aerodynamic point of view (red arrows).

The goal here is to push the air towards the outside of the front tyre as much as possible. As shown by the curvature of those two little winglets, they try to push the endplate vortices to the outside and consequently the front tyre turbulence as far as possible from the Venturi channels. 

Updates not working as expected

All these changes, however, didn’t work as expected, as they made the car even more unstable and with a lot of understeer during the mid-corner phase. Verstappen was everything but comfortable in the car on Friday, making a lot of mistakes and struggling with grip.

Waché underlined these issues as well at the end of testing: "It was not as smooth a test as we expected and the Team expected. But it is better to find some problems here than later down the line and it is why we are here, to understand the car. I am not as happy as I could be because the car did not respond how we wanted at times, but it is going in the right direction, just maybe the magnitude of the direction was not as big as we expected and it’s something we need to work on for the first race and future development.”

His words are proof that Red Bull still need to work hard to fully understand how the RB21 works and find a set-up that should allow both drivers to extract its potential. As the French engineer explained, the updates didn’t mitigate this issue, but at times made the car even more peaky, promptiong behavioural changes corner to corner. 

In conclusion, Red Bull will arrive at Melbourne not as the favourite, but rather with some work to do to understand their car and make it work in order to fight Ferrari and McLaren for important places.