The 2022 rule changes were revolutionary, and they changed the way Formula 1 cars look and perform dramatically. Drivers had to adapt and learn how to drive these cars, but it also presented a challenge for the engineers. One challenge is what is known as porpoising.
Porpoising in F1 involves the car being repeatedly sucked down to the ground and rapidly pushed back up. The ground effect sucks the car towards the track, loading the suspension, then airflow stalls under the car. Downforce then decreases, the suspension unloads, and this pushes the car back up.
Porpoising is a problem that F1 teams have not had to deal with since the early 1980s, and it has forced the engineers to work overtime to solve the problem. Some teams are more affected by porpoising than others, and below we take a closer look at what exactly porpoising means in F1.
An Important Note On The Complexity Of Porpoising
Before we discuss what porpoising is in Formula 1 and what causes it in more detail, it’s worth mentioning that it’s a very complex phenomenon. It can be caused by a wide variety of different things, from mechanical components like the suspension to the overall aerodynamic design of the car.
Many Different Causes
For example, in 2022, Mercedes left a lot of their floor area exposed, and this meant it could bend considerably under different loads. This would naturally lead to changes in the aerodynamics of the car at high speeds and therefore high downforce levels. This could cause downforce fluctuations, leading to oscillations in this part of the floor and then also cause porpoising.
If the heave and pitch of the car are not well controlled through the suspension setup, a similar phenomenon can occur. These up and down movements can create fluctuations in the airflow and therefore also the downforce, leading to porpoising.
However, both of these factors (the design of the floor edges and the suspension setup of the car) can influence each other, and how the car is designed can dictate which factors have the strongest influence on the porpoising the driver experiences. It’s not all about the ride height of the car, and there are clearly many different variables at play.
It’s Easy To Oversimplify
Porpoising is often oversimplified, which can make the basics easier to understand for beginners, but it usually means the nuances of this phenomenon are lost. If the issue of porpoising was as simple as some sources suggest, teams like Mercedes wouldn’t have spent the better part of the 2022 F1 season trying to fix their problems!
Unfortunately, in order to make the issue of porpoising understandable by a wider audience, we do need to simplify some concepts below. However, we aim to provide the most comprehensive answer possible, so you can truly understand what causes so much of the bouncing that has plagued certain teams. But first, let’s gain a basic understanding of the ground effect.
What Is The Ground Effect In F1?
The 2022 aerodynamic rule changes mean that Formula 1 cars now use the ground effect to produce a lot more of their downforce than they did in the recent past, rather than largely relying on the various wings and other downforce generating components on the body of the car. This was done in an attempt to limit the “dirty air” coming off the backs of the cars, making it tough for cars to follow each other.
But it’s important to note that F1 cars have used the ground effect since its discovery many decades ago, but to a lesser extent than what we see now. Take the following definition of the ground effect and it becomes easier to see how this was the case even before 2022:
Ground Effect: The ability of a downforce-generating surface to generate more downforce when in close proximity to the ground
This isn’t the definition you’ll commonly find online, as it’s important to note that the ground effect works in both directions, and is largely referred to in the context of lift when discussing aeroplanes. Lift is downforce in the opposite direction, with downforce sometimes being called ‘negative lift.’ That’s not important for our discussion, but it’s worth pointing out in reference to this definition.
Let’s get back to the idea of F1 cars using the ground effect before 2022. Bearing the above definition in mind, it becomes easier to imagine that F1 cars have always used the ground effect (at least since the engineers began understanding its uses). Formula 1 cars run very close to the ground, meaning there are components like front wings and floors that are “in close proximity to the ground.”
The underfloor and diffusers of the cars, especially since the early 2000s, have been responsible for producing anywhere between 40% and 60% of the car’s total downforce. This has largely been thanks to the ground effect allowing these low-to-the-ground components to produce so much of the car’s downforce.
However, the 2022 aerodynamic regulation changes shifted downforce production even more towards the use of ground effect, and the underfloor and diffuser now produce more than 70% of the car’s total downforce.
Venturi Tunnels
F1 cars now rely a lot on Venturi tunnels to produce underbody downforce (along with the diffuser). The very simple explanation is that these Venturi tunnels accelerate air under the car, leading to an area of low pressure, creating a pressure difference above and below the car, effectively sucking the car to the ground.
This is known as the ground effect. The ground effect was first used in F1 in the 1970s. However, it was banned for being too dangerous, as the cars were reaching incredibly high cornering speeds. Engineers now have a better understanding of how it works, and so it was implemented in 2022 in a much safer way than it was back then. However, one consequence of the ground effect is a phenomenon known as porpoising.
What Does Porpoising Mean In F1?
Porpoising in F1 refers to the bouncing effect of the cars as they travel at high speeds on the straights. The cars bounce as a result of the ground effect sucking the car so low to the ground that the airflow stalls underneath, before the suspension quickly pushes the car back up.
The term “porpoising” was first coined in the late 1970s by Mario Andretti, but it was used once again during the Barcelona and Bahrain pre-season tests in 2022 to describe what the cars were doing on the straights. Just like a porpoise that jumps through the water while it swims, the Formula 1 cars were bouncing up and down while on the straight in a similar manner.
How Does Porpoising Happen?
As the air passes through the Venturi tunnels in the floor of an F1 car, the suspension becomes loaded and the car is sucked into the ground, due to the large pressure difference above and below the car. The air exits through diffusers at the back of the car, helping to effectively suck more air underneath the car, and therefore creating more downforce.
Once the car reaches a certain speed on the straights, the car is effectively generating so much downforce through the ground effect that the car gets very low to the ground, and it may even touch it.
Stalling Diffuser
When the car gets too low to the ground, no more air can be sucked underneath the car, and the air begins to stall at the edge of the diffuser. Stalling here basically means the low-pressure air below the car separates from the underbody surface (flow separation). This causes a rise in pressure in this area, resulting in a loss of downforce, and it’s especially apparent in the diffuser region.
The suspension then unloads, lifting the car up rapidly, as the suspension is very stiff and wants to almost ‘snap’ back into its normal resting position. When the car rises, more air flows under the car and through the Venturi tunnels and through the diffuser as normal.
This generates downforce, which sucks the car towards the ground and loads the suspension again. This happens rapidly over and over again in a repeating cycle, leading to the bouncing effect known as porpoising.
You may have also heard the term stalling in reference to aeroplanes. The same thing is happening just in the opposite direction. As the plane’s angle of attack increases beyond a critical angle, the airflow separates from the wing, and the plane loses lift, going into a stall. (The shape of an F1 car’s diffuser can be thought of as an upside down wing.)
Important Note: Stalling is a complex aerodynamic concept, and we won't go into much detail on it here. Other effects are also at play, such as vortex breakdown and hysteresis, and to avoid getting too technical, we've kept it fairly simple.Summary Of Porpoising In F1
The basic cycle of porpoising in F1 is as follows:
- The car gets sucked towards the ground at high speeds as downforce increases, loading the suspension
- The car gets so low to the ground that the airflow slows down at the surface of the floor or diffuser
- Its pressure rises, causing the car to lose downforce
- The suspension unloads due to lack of downforce, pushing the car back up
- Air flows under the car once again, generating lots of downforce
- The car gets sucked towards the ground again, loading the suspension, and the cycle repeats
How Can F1 Teams Combat Porpoising?
The cause of the porpoising issue is the floor of the car, and teams don’t want to change the floor too much as they risk losing some of the ground effect and therefore downforce through the corners. The simple answer to porpoising is to raise the entire car up from the ground by altering the ride height.
By raising the ride height of the car, air is less likely to become trapped underneath the car in the Venturi tunnels (as there is just more space for it to flow underneath the car), leading to the stalling of the diffuser. This significantly reduces the porpoising effect.
However, there is a huge trade-off to raising an F1 car’s ride height. In order for the ground effect to be as effective as possible, the cars need to be as low as possible to the ground in order to trap the air and create a vacuum (without going too low), sucking the car to the ground, allowing it to take corners at high speeds.
When raising the ride height of the car, teams will lose some of this downforce and therefore will also lose some of their cornering speed. But raising the ride height also raises the car’s center of gravity, affecting its balance in the corners. The key is finding a balance between minimizing porpoising but keeping as much downforce on the car as possible.
Key Fact: Each F1 car will have an optimum ride height range where it will produce the most downforce. Teams will try to run their cars within this window as best they can, and going too low or too high can both result in a loss of downforce.Active Suspension
One sure way to solve porpoising is by using active suspension. Active suspension is a system that was first used in F1 in 1983 to combat – you guessed it – porpoising. It was an incredibly clever system that could automatically raise and lower the ride height of the car while the car was out on track. It was used to maximum effect in the early 1990s, before being banned.
Active suspension would automatically, via electronics and various sensors, adjust the car’s ride height in different ways to maximize the grip of all four tires at any given moment. However, when it was first used in the early 80s to combat porpoising, it was simply designed to prevent the stalling of air under the car that led to the up and down movement.
Active suspension was banned for the 1994 season as it was deemed too dangerous and was effectively a driver aid, seemingly taking away from the skill aspect of the sport. However, active suspension would immediately solve F1 teams’ porpoising issues were it brought back, but that’s unlikely to happen any time soon.
How Does Porpoising Affect F1 Lap Times?
Porpoising can negatively affect F1 lap times if it is not managed effectively. As the cars tend to porpoise on the long straights, they suffer in terms of their top speed. If they were to porpoise through the corners, it could cause the car to become very unstable, which could lead to a crash.
With the violent bouncing on the straights, F1 cars may struggle to reach their true top speed. Porpoising naturally slows the car down on the straights as the car will not be able to run as smoothly as possible. As the air underneath the car loads and unloads the suspension, the top speed of the car will suffer.
While porpoising does seem to only be an issue at the very high speeds towards the end of straights, if it were to occur through very high speed corners, it would not just affect lap times. It could also make the car so unstable that the driver could struggle to keep it on the circuit.
Does Porpoising Damage The Car?
Porpoising can not only cause the car to struggle with top speed and lap times, but it can also damage the car if the porpoising becomes too violent. With the violent bouncing, there is a risk of the floor of the car hitting the tarmac too hard and getting damaged.
This is a more serious problem than it was in the past as the floor is crucial to the performance of the car through the Venturi tunnels. With a damaged floor, the car’s ground effect would suffer massively. This means that the car would lose a huge amount of downforce when cornering. This would not only affect lap times, but it would become dangerous too.
Other parts of the car can become damaged with excessive porpoising too, as was the case with Haas at the 2022 Azerbaijan Grand Prix when porpoising caused a water leak on Mick Schumacher’s car as a result of pipe clamps coming loose.
Is Porpoising Uncomfortable For F1 Drivers?
Porpoising is uncomfortable for F1 drivers when they have to deal with it for extended periods of time. Many drivers reported that the porpoising effect is difficult to cope with when the car is going 190 miler per hour down the straight, and in the past it gave drivers headaches.
Charles Leclerc compared the porpoising effect to ‘turbulence on an aircraft’ and said that it does make him feel ‘a little bit ill.’ Judging from the front facing onboard cameras it’s clear that porpoising is very uncomfortable for the driver, especially if they have to complete a full race distance with porpoising on every long straight.
Final Thoughts
Porpoising in F1 is the up and down bouncing movement of the car at high speeds. Porpoising occurs as the car is sucked towards the ground as a result of massive amounts of downforce, before springing back up as it loses downforce when it gets too close to the ground, with the cycle repeating.
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