How keel probes and Pitot tubes thrive on F1 cars

Winter testing has begun, and F1 cars are once again equipped with a series of sensors and other devices. Although these are now commonplace during pre-season sessions, it is interesting to briefly examine their technical details.

Winter testing has finally begun in Barcelona, giving teams the opportunity to translate months of research and simulations carried out in the factory into real data. While engine performance always makes the headlines, aerodynamics are just as crucial. However, conditions on the track can differ from those in the wind tunnel. The Barcelona sessions therefore become a laboratory where scientific measuring devices are once again deployed to validate and tune the cars for the coming season.

These devices, borrowed from aeronautics, are mainly Kiel probes and Pitot tubes. Although they have different names, they have a similar function: measuring the speed of a fluid by detecting the dynamic pressure it creates.

In practice, the instruments mounted on an F1 car measure the influence and effectiveness of the numerous aerodynamic appendages. The Pitot tube The Pitot tube, shown opposite, is an aeronautical sensor used to determine the speed of a fluid. On an F1 car, it records the speed of the airflow at a specific point, as the speed of the wheels alone only gives an average value. The tube is essentially a hollow pipe that allows air to enter at a chosen location and houses the electronic measuring components. By comparing the Pitot tube reading with the speed of the wheels, engineers obtain information about tire friction and wear, adding another dimension to their aerodynamic analysis. The Kiel probe The Kiel probe is an advanced version of the Pitot tube: a streamlined Pitot tube that creates a Venturi effect around it. Starting next year, single-seaters will once again exploit this effect to gain aerodynamic advantage. The Venturi effect produces a low-pressure area that generates suction, allowing 2021 cars to stick to the road without relying on today's complex aerodynamic surfaces that induce drag and often dilute battles on the track.

Single-seaters are often equipped with Kiel probes arranged in grids that can be positioned at different locations on the chassis. “And the winner of the largest set of Pitot tubes of the day is… @redbullracing. Congratulations! #F1 #testing” – F1 Technical, June 24, 2015

These Kiel probes capture a wealth of data on the airflow around the car at multiple locations, allowing teams to verify and compare CFD and wind tunnel studies carried out in their factories. With the Venturi effect becoming more significant, we can expect these tools to be used less during the 2021 winter testing program.