How F1 teams juggled Spa’s contrasting downforce demands

The varying characteristics of the three sectors of Formula 1’s Spa-Francorchamps circuit means teams have to choose a compromise between straightline speed and downforce.

Carlos Sainz, Ferrari F1-75, Lewis Hamilton, Mercedes W13, Fernando Alonso, Alpine A522, Sergio Perez, Red Bull Racing RB18, George Russell, Mercedes W13, the rest of the field at the start

It was no different with the new generation of 2022 cars, but the Belgian Grand Prix highlighted some of the core strengths of the RB18 as it appeared to be quick on the straights but without hurting its pace in the twisty sector two.

Red Bull also had a few new parts for Belgium to help improve its performance envelope. The largest of those modifications was made to the transition in the bodywork between the sidepods and the engine cover, and also led to the lower wishbone fairing on the rear suspension being reprofiled.

The bodywork change results in a more bulbous surface, increasing the volume beneath (red arrow, inset), while also altering the airflow’s passage externally in a move that was seemingly a compromise between cooling and aerodynamic performance.

The alterations made to the lower wishbone are subtle and haven’t required any structural changes within.

Red Bull also has an indent in the floor above the diffuser to provide the necessary travel for the wishbone, given its overall proximity to the surface (small inset, blue arrow).

Another change made by the team to its mirrors wasn’t submitted for the car presentation documentation, likely given this is such a small change from a visual perspective.

Red Bull Racing RB18 mirror comparison

Red Bull Racing RB18 mirror comparison

Photo by: Giorgio Piola

However, the change made to the wing mirror surround will have some aerodynamic benefits.

Stretching the lower section of the surround out under the main mirror body (which has also been shortened, blue arrow) will alter the airflow’s response, not only directly but also on the airflow’s passage around the mirror body too.

It wasn’t all about the new parts on show for Red Bull though, as another interesting side story emerged, with Verstappen and Perez seen using different floor specifications in Belgium.

The Mexican favoured the specification first introduced at Silverstone and then again in Austria before it was unceremoniously abandoned. 

Red Bull Racing RB18 floor comparison

Red Bull Racing RB18 floor comparison

Photo by: Giorgio Piola

The floor features a design solution similar to Ferrari’s, with a cutout on the floor’s edge and a tongue-like section jutting out from it.

Verstappen, perhaps feeling it doesn’t offer the same performance for his needs, didn’t use the floor specification all weekend.

Ferrari had a new, lower downforce, rear wing and beam wing available. However, having evaluated it during the second free practice session, it opted not to utilise it during the rest of the weekend.

This is a tactic seen from Ferrari in the past when it has introduced lower downforce items, with the Scuderia instead opting to improve its performance in Spa’s second sector and also help with tyre degradation over the course of a race stint. 

Ferrari F1-75 rear wing comparison, Belgian GP

Ferrari F1-75 rear wing comparison, Belgian GP

Photo by: Giorgio Piola

Regardless of its decision not to race the new rear wing, it will likely feature again in the coming races.

The new specification takes up much less space within the box section that’s permissible and all but entirely removes the spoon-shaped flap design that’s commonplace under these new regulations, owing to the endplate transition.

Mercedes arrived at the Belgian Grand Prix after the summer break with some optimism that it might be able to challenge at the sharp-end, especially with the two title protagonists set to start further down the field owing to penalties.

However, it quickly became apparent that its drivers were going to struggle with a car that seems to be carrying too much drag at a circuit that demands aerodynamic efficiency.

Furthermore, the troubles it encountered in terms of tyre warm-up during the opening half of the season were also plain to see, with the Mercedes pair unable to fire enough heat into their rubber for one lap performance.

There were further changes from the team for the Belgian Grand Prix too, as a revised front and rear wing were deployed, while further optimisations were made to the floor, including the fences and its edge wing. 

Mercedes W13 floor comparison (arrowed)

Mercedes W13 floor comparison (arrowed)

Photo by: Giorgio Piola

The floor has been an area where the team has looked to try and improve its performance, with the latest change focused on optimising the relationship between the front portion of the floor and the ‘edge wing’.

Like some of the other teams on the grid, Mercedes has settled on a long edge wing that now runs almost the entire length of the allowable region. This is upturned at the front-most section to help with extraction, where a more scythe-shaped section takes over at the rear.

Both have been altered, with the upturned section now featuring just a single flow diverter, rather than the three previously employed (red arrows).

The scythe-like section has then been narrowed (see yellow line for reference), as the floor’s shape beside it has been altered, while the rear section of the floor and edge wing have been trimmed, creating the sort of taper ahead of the rear tyre that became customary under the 2021 regulations (see green line for reference).

Further modifications have been made to the floor fences (blue arrow) in an effort to work more effectively with the changes made both up and downstream, with the height of the secondary fence increased and the upper boundary edge altered too.

Interestingly, Hamilton opted not to use the new floor for qualifying and the race, switching back to the old parts.

Not listed in Mercedes’ submission for the car presentation documentation at the start of the weekend, the team also added triangular extensions for the upper surface of the halo (black arrow), a design which we’ve seen elsewhere and will undoubtedly help coerce the airflow as it moves down around the engine cover and sidepod bodywork. 

Mercedes W13 rear wing
Mercedes W13 trimmed rear wing

Clearly suffering with a drag deficit to its rivals, Mercedes had, in fact, introduced changes that it hoped would help around the Spa-Francorchamps circuit.

But, rather than introduce an entirely new assembly, the designers had set about improving the wing's output by making changes to the endplate’s wingtip and the upper flap.

The W13’s endplate is designed in such a way that the wingtip cutout can be changed to match the desired load being generated by the wing.

In this instance, the team opted to fill the void entirely (red arrow, left image), a trick we’ve already seen employed by Alpine earlier in the season, as it also looked to adjust the strength of the vortex shed by the wingtip.

A lower downforce top flap option was also tested by the team with the flap trimmed back (red arrows, right image) but abandoned as it seemingly didn’t offer the necessary offset required between the higher speed first and final sectors, and low speed performance required in sector two.

Alpine A522 floor fence comparison (green highlight)

Alpine A522 floor fence comparison (green highlight)

Photo by: Giorgio Piola

Alpine continues to make progress with the A522 as it optimised its package again.

For the Belgian Grand Prix the team continued to modify the forward section of the floor and its transition with the outermost floor fence. As can be seen in the comparison image, with the new design on the left-hand side, the floor has been pinched inwards around the shoulder.

This will not only have an impact on the external airflow and the relationship with the fence, it will also determine the airflow’s passage through the underfloor tunnel, altering the link with the fences as they turn out toward the edge of the floor.

Alpine A522 rear brake duct comparison

Alpine A522 rear brake duct comparison

Photo by: Giorgio Piola

The team also made modifications to its rear brake duct design as it continues to search for ways to offset the demands required for cooling against those for aerodynamic performance.

The change reflects the mood amongst the rest of the grid, with most teams opting to place the inlet on the inner face of the brake duct’s fence (blue arrow), rather than have its own inlet scoop (red arrow), which is a solution we’re more accustomed to seeing at the front of the car.

The new solution gathers the airflow as it passes between the fence and the tyre’s sidewall and directs it to the various channels connected within, some of which have been amended as part of the upgrade.

Meanwhile, the absence of the scoop means that any winglets residing on the outer surface of the fence are going to be less impeded and might even be optimised at a later date in order to improve performance further still. 

Alfa Romeo C42 rear wing Belgian GP
Alfa Romeo Racing C42 rear detail

Alfa Romeo introduced a new rear wing design for the challenges posed by the Spa-Francorchamps circuit, with the intent of lowering downforce and thus the drag being generated.

The wing has what could be considered more of a conventional design with the spoon-shaping used with these regulations to accommodate the transition to the endplate being flattened out.

However, the biggest change when compared to its usual design came to the shape of the upper endplate transition, with the panel cut diagonally across the front section down towards the wingtip cutout.

The team also had one of its usual wing specifications at hand with the upper flap’s trailing edge trimmed back, possibly as a fallback should its first choice not offer the performance it was anticipating (right image).

In order to facilitate the DRS mechanism, the team had to leave the central portion of the wing at its usual height though.

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