The new generation of F1 cars relies more than ever on the downforce that comes from the floor, but this has also led to the unwanted bouncing at high speeds that the teams faced in the first tests.
To reduce the negative impact that cars have on the airflow of the car behind them, Formula 1 has prepared a new set of technical rules that puts more emphasis on downforce from the floor while the front and rear wings and numerous aero devices behind the front wheels have limited potential.
Although there were fears that due to the more restrictive nature of the rules and certain standardized parts, the cars will be very similar to each other, this turned out to be completely wrong because we saw completely different concepts and solutions among the ten presented cars.
How Formula 1 increased aerodynamic potential of the floor
Since Formula 1 banned ground effect cars in 1983, which to the extreme used the principle used by today’s cars, the floor of the car had to be completely flat all the way to the diffuser, which started only on the rear wheel centerline.
The floor potential increased in 2017 when the diffuser started 175 mm in front of the rear wheel centerline. but engineers were given great freedom in the zone 430 mm behind the front wheels centreline where different aerodynamic profiles, bargeboards and vortex generators were allowed. which were very powerful weapons to increase control over the airflow under and around the car.
This led to record amounts of downforce, but also never higher levels of turbulence that prevented drivers from closely following each other because the loss of downforce was huge, especially when drivers were less than a second from their rival, despite the help of DRS.
As of this year, engineers are allowed to use high tunnel inlets at the beginning of the sidepods that may have four vertical strakes, including the outer one, to increase the volume of air entering under the car and thus the potential for downforce generation.
In order to make better use of the larger volume of air, Formula 1 has allowed engineers to use larger diffusers that start earlier than before, and have returned wings under the rear wing (beam wing) that create downforce itself and connect the rear wing and diffuser flows, increasing their efficiency.
How downforce depends on ride height
Downforce increases with speed on a square basis – if you have 100 kg of downforce at 100 km/h, in theory you will have 400 kg of downforce at 200 km/h. Of course, if we are talking about ideal conditions with constant ride height, but in practice downforce also depends on the distance from the ground, the angle of rotation of the steering wheel, yaw angle and the influence of wind.
For example, the front wing also depends on the distance from the ground due to its low position on the car, which at very short distances from the ground significantly increases its downforce, but the rear wing due to its high position does not depend so much on ground distance but on the quality of the airflow it gets.
Downforce obtained from the floor is also highly dependent on the distance from the ground because the amount of downforce increases dramatically as the distance from the floor to the ground tends to zero, which is one of the basic principles on which the ground effect is based.
That’s why engineers want a more stable mechanical platform that gives them a stable aerodynamic platform, and the extreme case of such control is the active suspension, which almost constantly maintains a constant distance from the ground and was used in Formula 1 in the late 80’s and until the end of 1993. .
Why F1 cars are ‘porpoising’ at high speeds
As the speed increases the downforce increases, but the distance from the ground also decreases, so the downforce increases due to this factor.
This was the case last year as well, when downforce from the floor was also the dominant factor, but this year its share in total downforce is even higher.
As the cars approach the maximum speed the distance from the ground approaches zero, and thus the downforce increases even more and comes into contact with the ground, causing airflow stagnation, dropping the level of downforce, which immediately leads to an increase in ground clearance.
Such cycles occur in very short time intervals and cause car bouncing at high speeds, which was evident in the test in Barcelona, although some teams struggled more and some less with this phenomenon.
Solution is simple, but losing as less performance as possible isn’t
To avoid bouncing, engineers must prevent the floor from scraping on the ground at maximum speeds, and this can easily be achieved by increasing the distance from the ground.
But then the downforce potential would be reduced at lower and medium speeds, in which downforce is most needed.
Another option is structural reinforcement of the floor to prevent or delay airflow stagnation and loss of downforce, and thus bouncing, while many options exist with suspension settings as well as changes to aerodynamic elements.
The suspension on the ground effect cars is quite stiff in order to have a stable mechanical and thus aerodynamic platform as possible, due to the impossibility of using an active suspension that would provide them with the best of both worlds.
Therefore, it will be a great challenge for engineers to find a solution for porpoising, while losing as little performance as possible in different types of turns and braking, when the front height from the ground decreases sharply and the rear increases.
Porpoising could potentially become a political issue in Formula One as well, as teams that fail to find an effective solution (i.e. lose more downforce than rivals in tackling the issue) could play the safety card and ask the FIA to change the rules.
F1 teams may never completely get rid off porpoising
McLaren is one of the teams that had the least problems with porpoising in the pre-season test in Barcelona, but their technical director James Key says that they are not sure how they managed to avoid it.
“We had a few test things that promoted it a little bit more, but when we removed them the bounces decreased so you can handle that aerodynamically as well,” Key said.
“It’s not a topic for us at the moment, it doesn’t mean it won’t come back with further development, of course. We’ve suffered a bit from that too, but for now it’s not a big concern or distraction for us drivers.”
“I would like to say that we were super smart, but the reality is that it is very difficult to simulate. I would be lying if I said that it is up to the design of the car, I think it is a phenomenon we will all get used to with these cars and I hope we will be able to solve it in time. ”
“I think there will always be partial reactions like that because of the proximity to the ground because it’s ground effect cars.”
“I think it’s built into them and that’s what we’re seeing now. But I think we’re going to learn to deal with it. There’s still a lot we can find about new cars and a lot we can learn.”
“So I think jumping is a phenomenon that you can’t completely solve because it’s a physical thing. But when it comes to managing it, I think it can become a significantly smaller problem after some development work.”