Tech Insight: the aerodynamic set-up of the 488 Challenge Evo

The 488 Challenge Evo has introduced several refinements to improve handling, quality and consistency of performance, and to offer drivers more fun behind the wheel. One of the main innovations is a first for the Prancing Horse's one-make series, that is, the option to modify the front and rear downforce independently so that the balance is always under control without altering the height of the car from the ground. The driver can select different configurations for each race, depending on the circuit and the weather conditions. This solution, like the others specific to the Evo package, grew - as always for Ferrari - out of a continuous dialogue with drivers and customers. It has a dual purpose: to improve the product both in terms of absolute performance and usability, to ensure that the Challenge offers a track experience to match that of the best racing GTs. In particular, talking of absolute performance, the development target required enormous aerodynamic work that ultimately yielded a 50% improvement in downforce under design conditions, while providing a top speed on the straight at Monza comparable with the previous version. The engineers also decided to shift the aerodynamic balance, that is, the percentage of vertical aerodynamic forces on the front axle compared to the total vertical forces, forward by 20% for greater precision when entering a corner, closer to the handling provided by GT3 cars. This work called for a significant effort, lasting about nine months, with about 2000 man-hours going on CFD and over 12000 man-hours spent in the wind tunnel, exploring around 400 different geometric configurations. The design of the car's underbody required heavy use of the wind tunnel. Just a few minutes in the tunnel let you measure the particular geometric configuration of the car on about 50 set-ups, ensuring healthy behaviour in any configuration that the body can adopt in relation to the wind and the ground when lapping the track. In this respect the underbody is the most sensitive element, the one that is most in need of monitoring. Development took place over two main stages: the first saw the identification of the most advantageous geometric parameters, identifying the areas that could provide better performance in a more flexible way. The second, after the car's shakedown, was more precise, following the testers' instructions in a series of very close loops between scaled wind tunnel, 1:1 wind tunnel and track. It is quite easy to notice the aesthetic and aerodynamic differences between the 488 Challenge and its Evo version. To produce the final form, the engineers began their work with the management of heat flows. While in the 488 Challenge the radiators partly vent hot air over the bonnet and partly over the underbody, in the 488 Challenge Evo the flows go over the underbody. This limits the possibility of increasing the car's downforce capacity in the wheel arch and on the side bumper, making it possible for the underbody to raise the overall downforce. From this starting point, the front splitter and the front underbody were radically redesigned in terms of volumes and the details of the elements that create vorticity. Specifically, the new design of the front splitter helps stabilise the front (essential in a racing car with these downforce values), desensitising the variation in downforce as the car height changes. The bumper is the other element responsible for generating front downforce. Its side volume was hollowed out to house a pair of flicks which, working in synergy with the underbody, maximise its performance. Then, the new rear bumper design's job is to reduce resistance. Its square shape and sharp edges frame the large exhausts behind the rear wheels, optimising the management of the wheel wake and reducing the car's drag. Last but not least, the small deflector wing under the external rearview mirror is there to straighten the flow from the front which has a strong element of upwash due to the changes described above, directing cleaner and more energetic air towards the intercoolers. The car's new configuration and the changed dynamic behaviour posed the engineers some challenging technical problems that led to original solutions boosting the potential of the Prancing Horse one-make championship car. While the greater aerodynamic balance enjoyed by the 488 Challenge Evo makes the car more precise, the optimal aerodynamic set-up range is narrower, making it necessary to "adapt" the aerodynamic configuration to different tracks. This led to the creation of an aerodynamic element capable of adjusting the front downforce differently to the simple height adjustment from the ground, which also has consequences for the vehicle's dynamics. So as well as adjusting the angle of the wing, the aerodynamic set-up can now be decoupled from the mechanical one. Specifically, the front slides have been fitted with calibrated openings that progressively reduce downforce on the front. Thus, the driver can reduce the wing angle together with the front underbody to create a car that has the same balance, but less overall downforce and less resistance for fast tracks. They can also individually vary the front underbody or wing configuration within a range of 15 percentage points of balance, without changing the height from the ground and in general of the car's mechanical set-up. The Ferrari test team decided on all these modifications, which were fundamental in the critical phases of incubation and development of the aerodynamic and vehicle design, offering continuous analysis and checking of the tons of data collected in virtual aerodynamic simulations, in the wind tunnel and on the simulator. As well as Maranello staff, the Ferrari Challenge Asia Pacific and North America drivers took the 488 Challenge Evo out on track, giving them the chance to start exploring and appreciating the car's new aerodynamic potential.