Pre-season testing heralds a vital opportunity for Formula 1 teams, as they employ various methodology to extract as much useful data as possible. Teams put flow-visualisation paint and aerodynamic rakes to use, playing an integral role in both pre-season testing as well as some in-season free practice.
The forthcoming F1’s 2024 pre-season test slated for 21-23 February at the Bahrain International Circuit is no exception. Excitement builds, as the Bahrain International Circuit is also hosting this year’s inaugural grand prix on 2 March.
Flow-vis or flow-visualisation paint comprises a fluorescent powder mixed with paraffin oil. It’s typically spread across certain parts of the F1 car, marking its purpose during pre-season testing and free practice sessions. It’s strategically useful with testing a new body part and primarily applied as the driver gears up to exit the garage.
However, precautions must be taken as to the amount of flow-vis applied. Too much may result in pooling, while too little may hinder valuable data collection. Teams usually use flow-vis to assess aerodynamic performance as when an F1 car speeds, the flow-vis moves across the body in sync with the airflow, leaving behind trails as it begins to dry in a real-world wind tunnel.
Analysis of the flow-vis revolves around the distinctive lines left behind by the fluorescing paint. These lines contribute significantly to understanding a car’s real-world surface flow and the direction of the air around car parts including the nose. Cameras record these lines after the car returns to the garage and prior to flow-vis removal.
When scrutinizing the flow-vis, teams primarily search for data anomalies, the critical one being where the air flow has deviated from its trajectory. The deviation from a car’s surface can become turbulent, resulting in increased air drag, decreased stability and reduced downforce. Close examination of such lines can help identify, and rectify, any aerodynamic issues.
In 2021, F1 saw a clampdown on wind-tunnel testing. Consequently, flow-vis paint has gained importance. It provides teams with the opportunity to implement a real-world wind tunnel using actual airflows, leading to a better understanding of where aerodynamic improvements are required.
In addition to flow-vis, F1 teams also rely on aero rakes throughout the entire season. These metal structures, akin to fences, are attached to the car during tests. The rakes are composed of Kiel probes and provide insight into the structuring of airflow on the car as opposed to how it flows off or around it.
The utility of an aero rake translates onto the actual circuit. A team is able to measure the bending of the metal fence due to the air’s force, subsequently calculating air pressure and velocity at different points around it.
These data points provided by the aero rake are fundamental in determining the most aerodynamic setup. It not only maps out the air flow around the car but also displays the impacts of different setups on the car’s performance. Without aero rakes, F1 teams would struggle in determining the optimal downforce levels.
One term often heard during pre-season testing is ‘glory run’. This describes when an F1 team lower on the ranking vaults up the testing timesheet after setting a lap with a lesser fuel load or softer tyres. It usually occurs when top-tier teams are experimenting with different setups leading to slower lap times. Thus, mid-tier teams often take a ‘glory run’ to boost their morale and also to assess their car’s performance in qualifying rounds.
Another practice seen during pre-season testing is ‘sandbagging’. This refers to F1 teams hiding their capacity during pre-season testing, ensuring their full potential is only demonstrated at the opening grand prix. This strategy prevents undue attention and protects new car parts from being copied by competitors.