Pre-2009, it was fairly uncommon to see the cars covered in Flow Visualisation Paint (or Flo-Viz). However McLaren were in a spot of bother with their MP4-24 and were taking every measure to raise their competitiveness and I distinctly remember the brightly coloured stuff plastered over the car numerous times in winter testing. Since then flo-viz has been a common feature during testing and even during free practice on a Grand Prix weekend. This boils down to the fact that testing is limited and – with the car’s aerodynamics becoming evermore complex – analysis of exactly how airflow is behaving as the car goes round on track is essential to development.
We hear a lot about wind-tunnel correlation and teams complaining that their car is not performing as it should compared to the figures they produce in the factory, and these statements are all very relevant in today’s formula. Although some wind-tunnels allow some degree of artificial pitch and yaw movements, most teams will be testing their scale models in a straight line to oncoming airflow. They can turn the wheels to the airflow in a bid to understand airflow behaviour during a corner, but you then have to take into account the load on the tyre, the sidewall compression, bumps, tiny driver inputs, air temperature… The list goes on! So what’s the best tool for on-track aerodynamic measurements? Pitot tubes quite possibly, but a flo-viz is another brilliant method. Continue reading