Does the increased reliance on ground effect cause a decrease in safety in Formula 1?

This article was written by Maxime Baillieux, Year 11

Introduction

To comprehend why ground effect was introduced we must first delve into the intricacies of this complex phenomenon. Ground Effect in Aeronautics is the name given to the positive influence on the lifting characteristics of the horizontal surfaces of an aircraft wing when it is close to the ground. This effect is a consequence of the distortion of the airflow below such surfaces attributable to the proximity of the ground. Essentially, the ground effect creates a cushion on which the plane glides for longer, and the plane floats. In Formula 1 ground effect is reversed, sucking the car down onto the track.

The diagram above shows the components of the underbody of a modern 2023-spec F1 car. The leading edge and trailing edge, also known as the diffuser, have the highest height above the track, though not necessarily the same. The diffuser throat, on the other hand, is the point of lowest height above the track. Ground effect in F1 is simple, the air is first taken in by the leading edge whose sole objective it is to take and direct as much airflow as possible to the floor, then as space narrows the speed of the airflow is accelerated and the pressure decreased until the diffuser throat, this causes a low pressure area underneath the car, and a high pressure area over the car which, like in wings on planes but reversed, causes the car to be sucked down onto the ground, because of this something called porpoising happens. In 2022 this was so bad that the FIA had to increase the ride height by 10 millimetres to prevent porpoising. Porpoising is when the downforce gets so strong that the diffuser throat gets so close to the ground that the air blocks itself which cancels out the downforce and the car comes back up where downforce comes back and the car bounces up and down which can be very annoying if not dangerous for the drivers.

Ground effect was not first introduced in 2022, it was actually introduced all the way back in 1977 by lotus, but it was a far more powerful system and caused a massive increase in downforce compared to in 2022, in 1977 the teams employed physical skirts which acted as barriers to prevent the air from leaking out of the underbody of the car which drastically improved the performance of ground effect. In the new 2022/23 spec cars the air is kept in using vortices created by flow directors as in the diagram below.

Research Review

In 1968, British Racing Motors, or BRM, introduced ground effect into Formula One racing when engineers Tony Rudd and Peter Wright conducted many tests on cars in a wind tunnel. They succeeded in producing a basic prototype despite not using a "true" ground effect race car. This led to the design by the Lotus F1 team in 1977 of the Lotus 78 race car.

This car wasn’t refined and so only had minor gains but in 1978, with the Lotus 79 they dominated the field, the Lotus 79 used two massive venturi tunnels (where ground effect happens) in both side pods as shown above. This car was so fast that all the other teams decided to copy it.

These teams were more successful than Lotus simply because they were bigger teams, had more funding and had a better overall car package to use. In 1981 the FIA decided to ban skirts and mandate a 6 cm ground clearance, but the teams found an ingenious solution to this problem, a hydropneumatic suspension was used on the Brabham cars to make the car lower to the ground when racing, allowing ground effect to function on track but when in the pitlane, the car would rise to meet the 6cm clearance mandated as the pitlane is the only place the FIA can check the cars. This proved to be dangerous as if the suspension failed it could cause the car to lose downforce on one or both sides and this caused the cars to behave in erratic manners and this caused many crashes. This was the main reason that the FIA decided to ultimately ban ground effect a couple of years later by mandating flat-bottom cars.

As previously stated Ground Effect sucks the car down like an upside-down wing, this causes massive increases in lap times and cornering speeds. Alan Jones’ pole position time for the British Grand Prix at Silverstone of 1’11.880 (236.324kph of average speed) was 6.61s quicker than James Hunt’s of two years previously. There is absolutely no denying the fact that ground effect made the cars excessively fast and for the time, too fast. Safety was not at the level it currently is now and this was dangerous. Too dangerous.

Many accidents occurred including the death of Gilles Villeneuve in which ground effect was partly to blame. This is because Gilles Villeneuve tagged the back of the car ahead of him which caused his own Ferrari to be launched into the air, this caused the ground effect to no longer work and so instead of being sucked down like it would’ve done if the wings provided enough downforce, which they didn’t due to the ground effect being prioritised, and so Gilles Villeneuve’s Ferrari nose planted into the ground, flipped over and catapulted Villeneuve out of the car, killing him instantly. Near misses also happened such as Rene Arnoux’s crash in the Dutch GP, the pressure and downforce caused by the ground effect on his Renault was so large that his suspension gave in and collapsed, causing him to plough into the barriers and almost hit spectators, luckily no one was injured. Again later that year a similar crash to Villeneuve’s accident happened, when August Pironi crashed into the back of the car ahead of him and much like Villeneuve, his car nose planted into the ground, luckily for Pironi, he only broke his legs but never raced again. More recently, in the 2022 season when ground effect was allowed to be used again, Guanyu Zhou suffered a massive crash on the opening lap of the British Grand Prix, once again similarly to Villeneuve’s accident his car was sent into the air after contact with Russell and Gasly, this caused ground effect to stop functioning and his car flipped over and hit the ground with a force of 19G’s, he then skidded across the ground upside down before ending up wedged between the tyre barriers and the crowd protection fence. The only thing that saved him was the halo.

Zhou’s crash happened in 2022, when ground effect was reintroduced, this reintroduction caused a lot of problems, most notably porpoising which can potentially be dangerous as it can make the cars unstable and cause back pain on the drivers. The 2022 season showed the lack of experience of modern F1 teams with ground effect, this was caused by the absence of engineers and designers who worked in this period, as well as the absence of reliable simulations that proved to work as it was the first season in which ground effect was used after a more than 25-year break so no reliable data to input into the simulations were present, all of this caused issues with the early 2022 ground effect cars such as porpoising.

Discussion

Ground effect is in its essence dangerous, this is because it makes the cars’ cornering speeds much higher which causes a higher risk of fatal accidents in the case of a tyre puncture, a simple crash with another car or a suspension failure. 

This last point, a suspension failure was made even more likely with ground effect as the pressure difference and the force keeping the car on the track is so immense that suspensions have to resist even more force than before which can make them prone to failure such as in Rene Arnoux’s crash. There is no mandated force that suspensions need to hold up but generally the force exerted on them during deceleration is around 5gs so we can assume that the suspension has a maximum force limit of around 7 to 8g counting a safety margin and collision safety margins. The image below shows the basic formation of a F1 suspension, the suspension used by Mercedes AMG Petronas F1 Team on their W10.

The diagram shows the different components of the suspension, the sections that need to support the weight and forces acting on the car through the tyres are the Pull Rod, Track Rod and Lower and Upper Wishbones. The Heave Spring and Heave Damper are used to fine tune the suspension depending on the track to make it stiffer or less stiff etc. The problem is that with ground effect, the Pull Rod, Track Rod and Lower and Upper Wishbones will have to endure much higher forces which could cause fatigue of the actual material, carbon fibre, and even though carbon fire is made to resist large forces, an increase in forces will naturally cause the carbon fibre to break more easily, simply because the forces it is exposed to are much higher.

The second danger is a tyre puncture, tyre punctures can be caused by pre-existing debris on the track, an overload of lateral forces or simply bad luck. However a short and small puncture can have catastrophic consequences, the most well-known accident caused by a tyre puncture was Max Verstappen’s famous crash in the 2021 Azerbaijan Grand Prix where he suffered a left-rear tyre failure on the main straight at extremely high speeds which

caused his car to swerve left and right before crashing into the barriers on the right hand side of the track. This failure was caused by a “circumferential break on the inner sidewall, which can be related to the running conditions of the tyre” according to Pirelli, the F1 tyre supplier. Even though this didn’t happen in ground effect cars since in 2021 ground effect was not used, this shows that it can happen, and with an increased amount of downforce on the cars, if this happens again in a high speed section of a track, especially if on a corner, the consequences could be even more dangerous and potentially risk the drivers lives.

Ground effect was introduced to help promote closer racing, this is because the vortices generated by the front and rear wings on non-ground effect F1 cars were so big that they caused zones of ‘dirty air’ behind the cars which caused the air to be disturbed, below is a diagram showing this.

The cars on the left show the previous spec of cars, these cars create unstable vortices which can be seen by the airflow and wake turbulence flows around the car, behind the car this causes unstable and unpredictable air which causes the following cars to lose a lot of downforce. The instability of the air can also cause some downforce-producing aerodynamic sections to not work as well as they should, this can lead to high speed downforce losses in a bad manner which can be dangerous. This dirty air also stops the cars to stay close to each other because a driver with less downforce will need to use the mechanical grip provided by the tyres a lot more which can overheat the tyres and cause the driver to have to slow down as the tyres themselves now lose grip as well, this is why ground effect was introduced. The cars on the right hand side have a thinner ‘bad air’ flow, as well as this, the 2022 spec cars also project the dirty air upwards. Ground effect is hence seen to make the airflow more controlled and not as ‘dirty’ behind the cars. This allows the car behind to follow closer the cars ahead as the air is sent above the cars which helps to improve the safety as there is not a massive drop in downforce that could cause a spin or sudden lack of grip that could lead to accidents.

There are not many different ways to achieve downforce apart from using ground effect or normal inverted wings as in pre-2022 spec cars. This is because the only way to create downforce is to have a pressure differential between the top and bottom of the car. This means that the only ways to have downforce is either to use wings to create upside down lift, or to employ ground effect to accelerate the air below and create this pressure differential. However, one team, Brabham racing did attempt to use another solution, a fan. The fan was powered by the engine of the car and was used to suck the air clean out of the bottom of the car, creating an immense pressure differential and hence creating downforce. The BT46B was referred to as the ‘Fan Car’ but only raced once, even though the FIA had cleared it to race for the whole season. However, in the only race it raced, it won by a large margin. The fan was absolutely massive and could clearly be seen as shown in the image below.

Safety has, and always will be, the main concern in motorsport, more specifically in Formula 1, Formula E, IndyCar and all single-seater, open-wheel motorsports. This is because of the nature of the sport, speed. The single-seater, open-wheel racing category is where Formula 1 falls into, this means the FIA, F1’s governing body has implemented many ways to reduce risks of fatal accidents. These include the introduction of the Halo for the 2018 season. The F1-spec Halo is made from strong, lightweight titanium tubing, which is then attached to the car’s carbon fibre chassis at three points for maximum rigidity. The system adds around 9kg to the car’s weight. The halo has served a pivotal role in safety in F1, it saved many lives, for example Lewis Hamilton when Max Verstappen and him collided dramatically at Monza in 2021 with the rear-left tyre from Verstappen’s car landed on the halo, without it Lewis’ neck would most certainly have been severely hit. Another example is the previously mentioned crash that had Guanyu Zhou involved, his car hit the tarmac upside down, without the halo he would’ve most certainly died from the crash. Both experts and Zhou himself said this. The most notable example however has to be Grosjean’s massive fireball crash in 2022. He was hit on the back of the car out of turn 2/3 in Bahrain and was sent right through the armco barriers, the images from the burnt out carbon fibre monocoque shows that the Halo had received shocks that without it, would’ve most certainly hit Grosjean on the head. The images are below.

Many experts also believe that the Halo would’ve saved Ayrton Senna from death in his fatal accident in Imola, this is because Senna was killed on the spot when one of his tyres impacted his head and killed him. With the Halo the tyre would’ve been deflected from the course it was on and saved Senna from the impact and death.

F1 also has a safety device called the survival cell, in the images showcasing Grosjean’s crash the survival cell is the part of the car that is still intact. The monocoque (survival cell) is made from Carbon Fibre and is thoroughly tested by the FIA, the survival cell must be able to resist a front impact and side impacts without compromising the safety of the driver. The monocoque must also be able to withstand immense heat and protect the driver in case of a fire to prevent the driver from being literally ‘cooked alive’.

Another important part of safety in F1 is the driver's suit. The driver also wears fireproof underwear and balaclava under the helmet. Wearing this suit, a driver can survive for 11 seconds at a temperature of 840 degree Celsius. FIA rules further say that the epaulette-like pieces on the shoulder should be capable of supporting the combined weight of the driver and the seat. The suit, much like suits for motorbike riders, should be able to withstand the friction force if by some unlucky accident the driver gets ejected from the car and scrapes on the ground.

Conclusion

Overall we can clearly see that F1 has improved a lot since the original introduction of ground effect, with all of the data collected and the evidence from real-life accidents, there is no doubt that Ground Effect is dangerous. However, as shown by real-life accidents as well F1 has come a long way in terms of safety, the cars are now much stronger and more resistant to accidents, the marshalling teams in place now are also a lot better than before, now whenever an accident happens the marshalls are instantly on site. In conclusion I believe that the research and information I have collected shows that no, the increased reliance of ground effect in F1 does not cause an increase in the danger of the drivers.

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