Technical evolution of Ferrari SF-24 and how F1 development direction affected performance
06/08/2024 18:04
Ferrari’s 2024 Formula 1 season is still a series of ups and downs, where the lack of stability is reflected in performance. The one-two finish in Australia with Carlos Sainz and Charles Leclerc in the third race, after a podium finish each for both drivers in the first two races, generated optimism, but then the season became inconsistent. The only noteworthy highlight is Charles Leclerc’s victory in Monaco, celebrated with Frederic Vasseur being thrown into the water.
But let’s analyze the technical evolution from the beginning. At the presentation, the SF24 immediately appears as a project derived from the previous car, which shows slight developments in terms of aerodynamics, but retains the old suspension system at the chassis level. The aerodynamic concept aims for a more efficient cooling system. The higher air intakes allow for cleaner flows that are less disturbed by the front suspension.
The heat extraction exploits the low-pressure field generated on the engine cover to release the high temperatures from the mechanics and radiators. With narrower and lower side pods, the housing of the exhausts and radiators changes, which, thanks to revised internal fluid dynamics, improves the old heat exchange problems. The lower lip side pod profile replicates the solution of the old RB19. The goal is to accelerate the internal flow, enhancing cooling.
If initially this solution seems to be a step forward, it will soon be changed, completely redesigning the side pods and air intakes based on the new technical trend introduced by Red Bull.
The SF24 is not a new project but one of continuity, replicating the basic technical concepts of the 2023 Ferrari. The starting point is therefore already one season old and, especially at the chassis and suspension level, the same system used before the ground effect is replicated.
With the SF24 project, Ferrari opts for development continuity, optimizing the shapes, sizes, and housing of the mechanics, radiators, and suspension. The only difference is the gearbox positioning. The design of the gearbox casing is more compact and 5 centimetres shorter, a solution that shifts the entire engine group towards the rear to correct the load problems on the rear axle present in the old project. Another change comes from the housing of the radiators.
The external dimensions remain identical, but the exchangers have been raised compared to the floor and especially tilted forward. This configuration allows gaining space at the bottom, creating a wide channel to allow more air to flow under the side pods. The wider peripheral flows are accelerated, aiming to improve the vortices protecting the floor and establish more profitable interactions between the upper aerodynamics and the underbody. The few changes to the SF24 project allow exploiting all the development work done at the end of 2023, capitalizing on the technical advantage of the old expanded and corrected aerodynamic solutions that respond on the 2024 car, which is little different from the previous one.
It is surprising how there are so few differences in the SF24 compared to the old chassis. Front suspension, low anti-intrusion bars, and driver position replicate the old configuration. The central part changes little. Slightly revised radiators and exhausts allow for slightly carving out the side pods when, instead, it would have been necessary to push the airflow much lower. With the shorter gearbox, instead, a weight shift and better car balance were achieved. The side pod design with a wider lower channel is the result of more tilted and raised radiators, giving space to aerodynamics redesigned to enhance downwashing and interactions with the floor and ground effect.
The anti-intrusion cone remains low and affects the design of the underbody suction boxes, forcing the flows into a path that loses efficiency. The fear of changing the chassis, following the old path, and maintaining the suspension with an unchanged scheme since 2019 led to correcting the problems of setup and tire consumption but not making the quality leap over the distance that Ferrari needed to compete with McLaren, Mercedes, and Red Bull in the second part of the championship. If in the first phase of the championship, before the developments arrived, tire consumption was reduced, and aerodynamic balance improved, the key lies in proper management of longitudinal lateral accelerations, which from the tire concentrate more on the carcasses, reducing stress on the compounds.
A result achieved by shifting a portion of the weight towards the rear, thereby increasing the load on the rear axle. This improvement is the result of the gearbox casing being shortened by 5 centimetres, which allowed the engine, tank, and hybrid part to be moved back.
By redistributing the exhaust clearances further back, a factor that increases the radiator inclinations contributing to lowering the vehicle’s center of gravity. The new setup, which makes the vehicle body less sensitive to roll in corners, reduces the load on the suspension, which is adjusted with more elastic elements to counter lateral accelerations. These interventions eliminate the negative legacies of the SF23 but do not guarantee a quality leap. By replicating a softer setup on the rear suspension, the irregularities of the track are copied more precisely, generating constant track-tire contact at the exit of the curve.
The SF24, thanks to a different distribution of forces on the carcasses, corrects the support in long curves, making cornering easier, a behavior appreciated by the drivers who, facing less understeer, better control the racing line during acceleration. These corrective modifications and the early-season developments respond to performance improvement, and the SF24 seems to be the only alternative to Red Bull.
But in this delicate phase of the season where Ferrari achieves positive results, it is decided to revolutionize the aerodynamics and replicate the path taken by Adrien Newey with the RB20’s side pods. A bold and perhaps inevitable decision, but one that disrupts traditional aerodynamics, affecting the data correlation between the old and new aerodynamics. The evolution brought to Imola is radical. Ferrari aims to increase performance by generating a leap in downforce through the new side pods. The native configuration, including front air intakes and direct entry flows, changes completely.
The elongated side pod with a beak profile overturns the cooling model. By channeling air from below, the flow rate is reduced, increasing entry speed, improving efficiency. This changes the vertical feeding of the S-duct. The higher pressure requires a wider internal channel, capable of emptying the lower air of the side pods, avoiding an aerodynamic blockage. By increasing the flow rate, the rear slot on the side of the car, behind the helmet, extracts a larger volume of air, a factor that makes micro aerodynamic modifications essential to restore the efficiency of the fluid vein.
A transformation that also affects the radiator box. From a structure with a high front intake, with the transition to the new side pods, the channel lengthens, and the intake hole is directed downwards. With the upper body profile being linear and continuous, turbulence is reduced, making the corrector on the side wing, installed to clean the flows on the wing, unnecessary. The narrower front section reduces air intake and requires a wider channel to enhance heat extraction, restoring the heat exchange of one of the most daring evolutions of the SF24.
In the immediate term, the changes are not satisfactory. The load increases but is redistributed differently, making the vehicle’s behavior nervous and unpredictable. It quickly becomes clear that new setups need to be studied to get the SF24 back on track and try to exploit the increase in downforce. A complex exercise that fails, and the task of finding new solutions tends to lead technicians and drivers astray. We had to go back to the car from Imola, and we lost two or three months of performance gains. In these weeks, we did not take the right path.
As work continues on load and balance aerodynamic variants, porpoising returns, compromising the forces acting on the car to stabilize the setup. The front tires, subject to bouncing, lose the stability condition essential to trigger grip, causing lateral slipping in the corner and greater degradation. The aerodynamic intermittence causes resonances on the carcasses that put the entire tire system in crisis. We are facing abnormal deformations of the structure that unload on the tread and belts, but especially on the sidewall. The effects on the track compromise the tread support, the discontinuous grip prevents the compound from producing the optimal temperature, and the car loses driveability, support, and steering precision, leaving Charles Leclerc and Carlos Sainz without tools to push.
Porpoising has even more damaging effects on the rear, directly affecting the rear suspension. Stiffness adjustments are now functional to compensate for the bouncing and not to improve setups to obtain more traction in driving, which at Silverstone proved to be one of the major problems of the SF24 in corner exit.
By July, it becomes evident that the lack of technical guidance capable of making targeted choices and finalizing technical efforts makes the job of fine-tuning the new SF24 aerodynamics even more complicated. The rush to put unvalidated updates on the track without an accurate comparison of wind tunnel performance led to this situation.
The SF24 chassis is put in crisis by the new floor, which generates too high a ground effect for a suspension system that has not been developed for this load progression. Five years old, the front and rear suspension systems no longer have development margins, capping the growth of unmatched aerodynamics of the chassis. The frequency of races in July does not help the Maranello technicians, who have to work on refining track setups, neglecting the search for new solutions to achieve an overall improvement of the SF24 system. Updates are still brought, some even anticipated in the hope of accelerating the development path.
New four-pin deflectors installed inside the wheels aim to enhance air deviation and boost the depression field at the side diffuser. Rolling turbulences deviate the flows under the car. By shooting air out from under the floor, high-pressure vortices are activated that counter infiltrations, increase depression under the venturi channels, and accelerate the air thanks to the diffuser extraction. The deflector architecture and the floor and extractor design are modified according to the load characteristics required by different circuits, following precise load maps pre-calculated at CFD.
In a moment of high internal tension due to the lack of results and Enrico Cardile’s announcement at Aston Martin, Maranello’s aerodynamicists continue to work, seeking corrective solutions that can help integrate the new aerodynamics with the old chassis. The new configuration of the intakes with an upper eyelid and a lower vertical exhaust channel requires a completely different cooling airflow. Hence the need for profiles that, respecting FIA regulations, flex downwards at high speed and recover the incidence in slow, ensuring both the load objectives in the curve and those related to the reduction of drag.
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