BUGATTI Tourbillon

First wind guidance experiments conducted in Italy

The Tourbillon, which had its world premiere in June 2024 at Bugatti’s headquarters in Molsheim, France, received rave reviews from customers and media worldwide. During the development phase, the car was required to push the limits of hypercars in every respect, and the evolution has been particularly notable in aerodynamics.

In the latest episode of A New Era, Bugatti engineers and aerodynamicists reveal the technological development process behind the airflow-driven tourbillon.

To achieve even more advanced aerodynamics than the world speed record-setting Chiron, Bugatti’s design and development teams first focused on fundamental research for the next-generation hypercar, solidifying the initial ideas after several months of CFD (Computational Fluid Dynamics) simulations.

For the next step, 15 months before the tourbillon was unveiled to the world, engineers and aerodynamicists headed to a state-of-the-art wind tunnel in Italy. David Sotaric, Head of Aerodynamics at Bugatti Rimac, recalls the first wind tunnel experiments:

“For this test, we brought in a scale model to examine the aerodynamic performance of the tourbillon for the first time. We swapped out various parts to evaluate different designs, and first pursued high-speed performance, then we tested handling efficiency and dynamic performance.”

From scale models to full-scale prototypes

At the heart of the wind tunnel testing program was a beautiful scale model, a work of art in itself. Perfectly mirroring the shape of what would become the tourbillon, the test model was painstakingly constructed from 250 3D-printed parts, with over 100 pressure taps fitted to the body panels.

This scale model played a key role in the aerodynamic development of the Tourbillon. The valuable data obtained from wind tunnel tests using the scale model, including mass flow, static pressure points and air speed, was carefully analyzed by aerodynamicists. Using cutting-edge simulation tools, the meticulously developed aerodynamic performance was thoroughly verified in the virtual world.

The development process involved a complex process of linking simulation models with actual test results to develop parts. The scale model used in the wind tunnel was then expanded over the course of a year to become a full-size prototype. Paul Burnham, Chief Vehicle Engineer for the Tourbillon, recalls the process as follows:

“After one year, our Tourbillon aerodynamic validation program has moved from a scale model to a facility capable of validating full-size vehicles. This is a natural step to further refine our simulation results.”

Significantly improved aerodynamics from the Chiron

The development team combined data from wind tunnels, real-world driving tests, simulations, and knowledge gained from hyper sports car development. For example, by reducing the size of the cockpit glasshouse, which has a large aerodynamic impact, the overall footprint of the complex vehicle was reduced, and this was combined with an advanced rear diffuser system.

“This has resulted in a significant improvement in the Tourbillon’s aerodynamics compared to the Chiron, allowing it to reach top speeds without deploying the rear wing and still maintain high stability. Burnham adds that aerodynamic developments in the wind tunnel have also contributed significantly to cooling performance.”

“The development of the Tourbillon began from scratch. We combined more than a century of combustion engine expertise with a cutting-edge, fully electric powertrain. However, the new hybrid system is very different from previous models, resulting in a highly complex cooling system.”

“In our wind conduction experiments, we thoroughly analyzed the airflow from the front radiator in Bugatti’s iconic C-line to the intakes behind the doors. By combining digital simulations with data obtained from physical scale models, we were able to achieve cooling performance sufficient to deliver the performance expected of the vehicle.”