Aerodynamics of Formula 1 cars

The technology used in Formula 1 is a secret behind seven seals: it is almost impossible to find out any details about modern cars. Nevertheless, sometimes it turns out to see something interesting. So, thanks to the accident of Mick Schumacher, we personally saw the bottom of the HAAS car. Under the current regulations, the bottom is considered the main area in terms of aerodynamics, because it provides half of the downforce generated by the car.

What is ground effect?

This is an aerodynamic effect that creates downforce in the area between the bottom of the car and the roadway. In fact, this effect is observed in all, without exception, bodies moving rapidly close to the earth's surface. Moreover, it can be both lifting and downforce.




- Mauro Forghieri, former chief designer of the Ferrari team.

But still, in relation to Formula 1, it is customary to call the ground effect only the downforce that occurs under the bottom of the car. For this year's vehicles, the share of the ground effect in the downforce reaches 60%. Another 15% is given by the wings (in total 30%), and the remaining 10% is accounted for by the external body panels.

How does the ground effect work? I will give an example from life. Imagine a narrow passage (preferably an arch) between two houses. In windy weather, the wind speed between them will be much greater than in open space. Why? This is how Bernoulli's law works: with a decrease in the cross section of the gas flow, there is an increase in speed (and a drop in static pressure, in our example, on the walls of the house). That is, to create downforce, you need to accelerate the flow of air under the bottom, so that an area of ​​​​low pressure arises under it, that is, downforce!

An excursion into history: the history of the ground effect in Formula 1

The first experiments in this direction were carried out by the chief designer of the Brabham team, South African Gordon Murray. Back in 1974, Gordon installed a cross skirt under the Brabham BT44 splitter, and found that immediately after it there was an area of ​​\uXNUMXb\uXNUMXblow pressure, that is, downforce.



The Lotus team found another way. Peter Wright used the profile of the bottom in the form of an inverted aviation wing, and in order to avoid air from getting in from the outside, he installed special screens along the sides, which were aptly called "mini-skirts". The bet on aerodynamic innovation paid off, and in the 1 Formula One World Championship, Lotus ground-effect cars driven by Mario Andretti and Ronnie Peterson were unmatched.




— Peter Wright, Lotus.

But perhaps the most extreme approach to mastering the "ground effect" was demonstrated by Tony Southgate. For Arrows A2, the wings were not provided in principle! The wingless car looked so unusual that the racers were afraid to speak on it. To reassure the pilots, Southgate even had to redo the aerodynamics by adding a rear wing. 



In this form, that is, Venturi tunnels plus "mini-skirts", the ground effect received wide and scandalous fame. After all, like any medal, there was a downside. Firstly, the depressurization of the bottom in a turn led to an instant loss of downforce and a departure from the track. And secondly, in conditions of work with such a large load, the designers were forced to make the suspension of the wheels rigid and short-stroke. In fact, the Formula 1 cars of the late seventies were a kind of kart equipped with a powerful engine. And this caused great discomfort to the pilots.



Thanks to the introduction of restrictions, the Automobile Federation has ensured that racing has become much safer and the cars more predictable to drive. In 1981, "mini-skirts" were banned, and in 1983, Formula 1 ordered only a flat bottom, which put an end to the ground effect. According to these rules, Formula 1 lived until last year.

But in 2022, the ground effect is back. And, as it turned out, not in the form in which it existed before.

The circuit diagram is similar, because in both cases long Venturi tunnels are used under the bottom. But since "mini-skirts" are still prohibited by the regulations, the team designers had to come up with a way to increase efficiency in other ways.



Now, to increase the downforce, "vortex generators" are used, installed at the entrance under the side pontoons. These "Vortex generators" serve to make the air flow under the bottom of the car as perturbed as possible, which means to reduce pressure even more - read: increase downforce.

Nothing like this has ever been used in Formula 1. However, the idea is not new, "vortex generators" have been used on racing vehicles for twenty years. For example, a similar bottom profile was used in the Indycar series at the turn of the 80s and 90s. Also, similar devices have been used on "sport prototypes" since the mid-90s.



An unpleasant surprise from the return of the ground effect was the long-forgotten “goat” or “porpoising” effect, which occurs when, under the influence of vacuum, the car sticks so strongly to the roadway that the air flow under it is interrupted. At this point, the downforce drops sharply, and the car "jumps" up. After that, the air flow is restored, and with it the downforce - the car again "falls" onto the road. And so it is repeated until the pilot slows down.



And although for the fans how to get downforce does not matter, the return of the long-forgotten "ground effect" has led to an aggravation of the struggle in the back of the field. That has a positive effect on the interest of spectators to the World Championship. Charles Leclerc and Max Verstappen have already given the audience a long forgotten taste of the struggle for victory, with numerous overtakes.