In Hinwil the veils finally fall on the first single-seater of 2023, after Haas, Red Bull and Williams have limited themselves to presenting only the livery. The 2022 Alfa Romeo was one of the most interesting projects on the track, with its own identity but at the same time caged in development by the same initial project choices. For this reason at Sauber it was decided to move on and make important changes compared to the C42, especially at the rear where some truly aggressive choices stand out. A new cooling system architecture has also made it possible to redesign the bonnet and sides, revamping the upper aerodynamics to make the most of the volumes released by the new rear suspension. The most evident innovations on the C43 are concentrated precisely in the upper part of the single-seater, but the fact that Hinwill decided to work on the suspension suggests that great attention has been paid to managing the height from the ground and to the aerodynamics of the underbody. For this reason, the Alfa Romeo 2023 presents itself as a change of concept with respect to its progenitor.
Technical director Jan Monchaux did not want to find out about it, but several small clues suggest that the C43 was built around a new chassis rather than the 2022 bodyshell. The main resources have been invested in restructuring the rear, both from an aerodynamically and mechanically. The new rear suspension helps to channel the flows coming from the sides towards the gearbox, the beam wing and the diffuser, but also to control the aerodynamic platform, above all the movements of the bottom while driving which affect the load released. “We made some changes to the rear axle”, Monchaux explains, “which led to a new cooling system layout which in turn changed the bodywork from last year. It’s not a revolution, it’s similar to what we saw on the grid last year, but it wasn’t possible to implement it without a change of architecture. One of the weaknesses we had aerodynamically was cornering performance at high speeds. We believe we have unlocked some potential with this new flow management between the rear wheels via the new bodywork.”
Alfa Romeo has published computer images of the new car, which while generally faithful to the C43 have been artfully modified in some key areas. The few leaked glimpses of the single-seater unveiled in the studio were decidedly more indicative. Despite the poor resolution, you can still see how Sauber has ditched last season’s push-rod rear suspension for a more common pull-rod arrangementthus moving the shock absorber spring unit to the lower part of the gearbox (1). All this has made it possible to reconceive the end part of the bonnet, which completely envelops the suspension arms. The end result is a rear with an incredibly tapered coca-cola zone (2), a clear step forward compared to 2022 in the ability to channel air towards the beam-wing and diffuser.
Even more, however, is the audacity with which the Hinwill technicians designed the remaining suspension arms to best condition the flows coming from the sides and channel them underneath. The leading element of the lower triangle reaches far forwarduntil it penetrates the side (3). It is a geometry already tested in 2022 by Red Bull and by Alfa Romeo itself, but which with the C43 is even more daring. Sauber’s choice in pushing the limits of mechanical design to get the most out of aerodynamics is courageous in this. However, it should be remembered that, unlike Haas, Alfa Romeo does not use Ferrari rear suspension, which is why the C43 is not a preview of what will be revealed on the SF-23.
Alfa Romeo had already tried to get a handle on the rear end with the 2022 single-seater, as evidenced by the intervention on the bodywork during the Imola round. However, the Swiss team was limited in the modifications to the rear suspension and the internal components of the bonnet, so much so that in the second part of the season development resources were then diverted to the front wing and underbody. “We did evaluations last year and we believed there were better solutions to manage the flow to the diffuser and rear wheels”explains Monchaux again. “Because of the decisions we had made in terms of architecture, however, we were stuck in the corner.”
With the C43, Sauber has thus not only redesigned the rear suspension, but also redesigned the arrangement of the radiators under the bonnet. The new single-seater abandons the raised-bellied concept of last season, initially shared by Aston Martin and then rejected after five races, instead embracing the flat-bellied philosophy now dominant on the grid (4). Part of the radiators have been raised and moved to a central position (5), resulting in a completely new bonnet. The single-seater featured in the study also sported a cooling grille right in the upper part of the bonnet (6), unlike the C42 which vented the hot air entirely over the bellies, compromising the cleanliness of the flows adhering to the surfaces. It is possible that in the hottest races the C43 will also open secondary grilles on the sides, as also suggested by the renders, although the huge terminal vent in the tail is able to dispose of a large part of the internal heat on its own.
In step with the new layout of the internal radiators, Alfa Romeo has also redesigned the side air intakes. The vents on the sides of the passenger compartment appear decidedly flattened and oblong when compared with the generous openings of last season (7), recalling the shapes of the Ferrari 2022. In addition to sheer aerodynamic performance, the new cooling system has also been designed to address the reliability issues suffered in this area last season.
Technical director Monchaux also spoke about the new features on the front end: “The development of the front is more difficult, the return on investment is smaller. That’s not to say there isn’t performance to extract, but since wind tunnel testing and resources are limited, strategic decisions need to be made about where to invest more. We worked on the front and there are some significant differences, but in general it’s an area where we struggle to extract performance due to regulatory limits, while there’s much more freedom on the rear”. Despite an investment defined as unprofitable, the front of the C43 is profoundly different from that of the C42.
Contrary to what is shown in the renders, the car present in the studio reveals a new position of the steering box, with the relative arms which are now located in the lower part (8). All this, combined with an apparently new outline of the nose, reinforces the idea that the 2023 single-seater originates from a different chassis than last season. In fact, the front suspension maintains the push-rod layout, but the attachments of the arms to the body seem to have been moved slightly lower (9). Instead, the offset in height between the front and rear element of each arm (10) is maintained, a solution already seen in 2022 and shared only by Red Bull to better direct the flows towards the entrance to the bottom and sides.
On last season’s finale Sauber had introduced a new front wing, an area where development would appear to have continued during the winter. The computer images in fact show an obsolete front wing, even before the Japan update, while the study car was equipped with a different spoiler. Definitive confirmation will only come from the first photographs taken from the track, although it is unrealistic that Alfa could have created a fake front wing for the sole purpose of throwing off the competition. From the same view also emerges a particular triangular section chosen for the air intake of the front brakes, another element to be monitored with interest at the first opportunity (11) but which is already confirmed in the renderings.
The changes to the technical regulations have not prevented Alfa Romeo from maintaining the blade geometry for the anti-rollover structure at the head of the car. By widening the fillet radii and lengthening the structure, Sauber was able to meet the new requirements on the larger horizontal section of the roll-hoop. Hinwill’s was the only team in 2022 to adopt a blade structure to save weight at the highest point of the car, lowering the position of the center of gravity. The air scope intake in the surrounding area reverts to a four-entry layout, already seen on previous Alfas and other cars produced by Sauber in recent years.
The computer graphics finally portray a particular conformation of the outer edge of the bottom, raised as per regulation by 15 mm compared to last season. The image shows how the ridge has been moved inland and used as an anchor wall for nine successive flaps to generate local loading and/or seal the bottom environment. However, any comment is postponed to the tests as, given the absence of the 2023 background on the machine under study, nothing rules out the fact that the published render is actually an attempt to misdirect.
The Alfa Romeo C43 looks like a single-seater full of inventiveness and not at all conservative in its choices, the only qualities that can be judged in static presentations. The goodness of the design choices is now subject to the verdict of the track and even if Sauber could count on a good starting base, this would require more constant development than that seen in 2022. The positive news for Hinwill’s supporters, however, comes from Maranello , with the new Ferrari power unit expected to make an important contribution to the mid-group struggle.
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