There was a lot of talk in the Barcelona paddock on this second day of testing, about the phenomenon of “Porpoising” which is complicating the tuning operations of the new aerodynamics of Formula 1 2022. The English nickname does not suggest much to our ears. Porpoise is the English name of the porpoise, a species of dolphin (zoologists forgive the simplification) that swims with a “jumping” style reproduced in the tank by swimmers. Porpoising was a well-known problem back in the days of the 1980s ground effect cars, and the return of this aerodynamic concept as the basis of the new 2022 cars has also brought this contraindication back to the surface. which is congenital to the ground effect itself. Let’s try to explain what happens: thanks to the Venturi effect generated by the new car bottoms, the aerodynamic load that the cars are able to generate from the underbody has increased considerably, and obviously this load increases with speed in a quadratic way.
To simplify the explanation, we could say that this “sucker effect” is always greater as the speed of the car increases. However, there is a point where the bottom is so close to the ground that the aerodynamic flow detaches from the bottom doing so “Stall” as they say in the jargon. At this point the load, or if you prefer the depression, disappears and the car’s suspension pushes it upwards, and the distance between the road surface and the asphalt is again sufficient to generate load again and the car returns to being sucked towards the low. This triggers an annoying spiral that causes the car to jerk continuously, until it reduces the speed and brings the load to lower and more stable values.
Bumpy road to the top for Charles Leclerc! 🤕# F1 pic.twitter.com/Z6a5e6d3bo
– Formula 1 (@ F1) February 24, 2022
We were able to verify with our own eyes this effect by lurking at the end of the straight of the Montmelò circuit, the point where the cars clearly reach maximum speed. Almost all single-seaters reached the point of braking with the rear that visibly hopping, as if the cars were traveling along a stretch of undulating asphalt. From a mechanical point of view the car practically entered into resonance, oscillating with a rather low frequency and as such visible to the naked eye.
Clearly, for the rider, braking in those conditions is an unmanageable situation, and it is certainly a condition that it takes away confidence on the braking point. Also because the braking point of a Formula 1 depends very much on the vertical load that the car is generating. Typically the rider must brake at the maximum possible speed in order to have the maximum vertical load and therefore the maximum braking capacity due to the contact between the wheel and the asphalt.
However, this recorded hopping effect does not translate into an alarm in terms of vehicle safety. It is “only” about finding the right compromise between average performance and absolute performance. In other words, the teams are looking for that set-up or that height from the ground that guarantees a level of downforce that may not be very high but still constant, which therefore does not create problems for the driver while driving. However, this is not a simple ground clearance problem because, as always in Formula 1, the car system as a whole must be considered, and not just a dimension of the problem.
To avoid the phenomenon of aerodynamic rebound due to “porpoising”, the teams can act both on the heights from the ground and on the suspension settings as well as on the level of aerodynamic load at the rear. It was in fact evident, again during our observations on the track, as the same car that presented this effect in standard conditions, he stopped hopping if he braked with the DRS fully open. Evidently, as the vertical load generated by the rear wing was missing, the distance between the bottom of the car and the asphalt no longer reached critical values. Not all cars were affected by the same problem in the same way. For example, the Alpha Tauri had a jolt-free behavior even with a closed wing, while the Alpine skipped conspicuously in braking. In the same way, in braking at turn 10, the famous return curve that leads to the slowest and most final part of the track, the drivers were still looking for the best braking point this morning. Perezat the first laps of the track with the very sophisticated RB18, he was even the protagonist of a strange excursion on the gravel of the escape route, having apparently missed the best braking point.
In short, if until last year the “stall” of the diffuser on the straight was a sought-after effect to lower the rear of the cars with a beaten trim, now with the ground effect cars characterized by an upright attitude, this unwanted phenomenon has become a problem. Certainly the Formula 1 teams already have the possible solutions in their pocket. As always, it will be a question of finding the solution that does not slow down the car too much by flattening its performance.
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