When in reference to motorsport, ground effect refers to using the underside of the car to produce more aerodynamic grip and thus quicker lap times. The details of how this is achieved may seem very confusing to you if you have read snippets about it before but in essence is actually very simple.
To help explain the concept better, we will do a quick recap of how all aerodynamic devices work. Traditionally aerodynamic grip in Formula One has largely been produced by the front and rear wings of the car. As you may remember from school, wings as used on racing cars are like an inverted version of those found on planes. On anything wishing to travel in the sky, the aim of the wings is to produce an upward lifting motion that will overcome gravity and get the vehicle off the ground. In car racing, the wing designed is flipped upside down and is used to produced a downward force, that rather than overcoming gravity assists it in keeping the vehicle on the ground where it belongs.
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| The basic principles of aerodynamic lift produced by a wing. |
The way in which these mysterious forces are achieved is through a very useful property of air, as well as gases in general. This is that as the speed of the flow of gas increases, the pressure of that gas decreases. This is called Bernoulli's principle. In an aircraft the wing is profiled so that the top of it speeds the flow of air around it and slows the flow of the air underneath it. This creates an envelope of air at unequal pressure around the wing, with it being lower above the wing than below it.
Another property of gases then comes into play, which is that if there is a pressure difference in any particular area of a gas then it will try and equalise itself by the higher pressure air moving into the lower pressure area. Fortunately for aerodynamicists, as the wing sits between these two pressure differences the effect is that high pressure air pushes the wing towards the lower pressure area and creates lift. From this new knowledge it is now clear how an F1 wing works. With the lower area of pressure below the wing, the air tries to force the car into the ground and produces aerodynamic grip as a result.
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| The classic F1 design of a large wing front and rear to produce downforce. |
Two of the big problems with over body wing derived aerodynamic grip if you are car an aerodynamicist in the sport are the facts that this downforce comes at the high price of large amounts of drag, which slow the progress of the car through the air and the fact that F1 regulators have an annoying habit of limiting the dimensions and locations of the wings on the cars for safety purposes.
It was the Lotus team that first began experimenting with novel ways to generate downforce on a car other than the wings in the early 1970's. Using a wind tunnel they came to realise that it was possible to generate previously undreamed of levels of aerodynamic grip by profiling the underside of the car to produce lower air pressures than the top side of the bodywork. Generating grip in this way overcame a lot of the drag restrictions of running wings on the external body work of a car and at the time was not an area covered in the rulebook at all, so offered designers a free hand in their work. The downforce was achieved by profiling the car so it's two sidepods effectively became a pair of big, inverted aeroplane wings.
The first car to make it to a race using these principles was the Lotus 78, which made it's debut in 1977. This produced only 75% of the intended level of downforce, but proved the concept with some solid results and paved the way for the Lotus 79 which refined the concept further. The '79 took American Mario Andretti to the title following year, but the successor car Lotus designed for 1980, the Type 80 was a lemon. Attempts were made to update the '79 but by this point all the other teams had caught them up, leaving Lotus uncompetitive. This was a position they did not really begin to recover from until the end of the ground effect era.
The "wing car" design at first favoured the privateer teams and their Cosworth DFV V8 engines because these power plants were compact and allowed engineers to sculpt the airflow round the rear of the car more effectively than the likes of Ferrari with their bulky but powerful flat 12 engines. This ensured that the UK based, non manufacturer teams were able to hold the performance advantage over the works teams during the early years of the ground effect era, despite being well down on horsepower.
This situation began to gradually turn on it's head however with the arrival of Renault into Formula One in 1977. The French outfit pioneered the use of smaller, turbocharged V6 units that were even better suited to ground effect designs than the DFV. At first Renault had their hands full just stopping this engine from exploding after a few laps and it wasn't until 1979 that they managed to produce a ground effect car and marry it to an engine that could last a race distance. When Jean-Pierre Jabouille took pole at the 1979 South African GP then pole and victory at the French GP later in the season the writing was on the wall for the privately owned teams.
Ferrari soon followed Renault's lead and by the dawn of the 1980's the initiative was very much with the manufacturer teams again as turbo power was beginning to look like a pre requisite for success. Privateers were faced with the choice of find a manufacturer willing to build them a turbo engine or face being not competitive even with a ground effect car.
By late 1980 it was a clear case of the "haves" and the "have nots". The privateer teams began pulling all kinds of dirty tricks to level up what they saw as an unlevel playing field such as running their cars underweight. The FIA were also becoming concerned by the whole thing. Cornering speeds were becoming unacceptably high because of the increased downforce offered by ground effect cars. The dawn of the turbo era made it clear that this problem was only going to get worse. In addition to this the "wing cars" had a critical design flaw that could potentially prove fatal in the right circumstances.
If a ground effect car was to hit a kerb, or worse still the wheel of another car, the car would be lifted from the track high enough to break the suction underneath. Suddenly robbed of all of their downforce, these cars could then rapidly become airborne. Indeed the ground effect era saw several spectacular, aerial accidents which culminated in the death of Gilles Villeneuve and the career ending injuries of his Ferrari team mate Didier Pironi during the 1982 season. Something clearly needed to change as Rene Arnoux's accident at the Dutch GP in 1980 demonstrates...
The way the teams had been minimising the risk of loss of suction and increased overall downforce had been to use ultra stiff suspension to keep the cars as level as posible (and the drivers as uncomfortable as possible) and by fitting flexible rubber "skirts" along the edges of the sidepods. This stopped higher pressure air along the side of the car being drawn into the low pressure area underneath it and blunting the suction effect. These skirts moved up and now in relation to the sidepods as the cars went over bumps in the track to keep the seal tight.
The FIA saw this as the weak link of the design and started moves to limit the effectiveness of the "wing cars". For the start of 1981 these sliding skirts were banned and the minimum ride height of the cars raised with a view to reducing cornering speeds. However, the wording of the new regulations stated that the car need only be at this new ride height in the pits. Thus, it didn't take long for Brabham chief designer Gordon Murray to come up a hydraulic suspension system that could raise or lower the car's ride height depending on whether it was in the pits or not.
The rules quickly turned out to be unworkable and a compromise was sought for the remainder of 1981 and the following 1982 season. Skirts were allowed again, but only in a toned down "fixed" version and the ride height restrictions were removed.
From the beginning of 1983 the concept was banned entirely and cars reverted to a flat profiled undertray. This design remained in the rulebook until it too was deemed unsafe after the catastrophic 1994 season. There is something of a parallel between the dark years of 1982 and 1994. Both were set against a backdrop of uncertainty after hastily introduced rule changes designed to eliminate potentially dangerous technology from the sport. Both seasons featured the deaths of two drivers as a partial consequence of these changes.
If ground effect had continued to be allowed in the sport it would no doubt have brought about the earlier implementation of some form of active suspension system amongst the teams. The benefits of such a system were even more stark for ground effect cars than flat bottom ones and Lotus had begun experimenting with such a system as early as 1982. This would have raised the terrifying spectre of active ride ground effect cars running during the very height of the turbo era with all it's monster power excesses...
Thanks
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| A drawing showing clearly how the ground effect concept works. |
The first car to make it to a race using these principles was the Lotus 78, which made it's debut in 1977. This produced only 75% of the intended level of downforce, but proved the concept with some solid results and paved the way for the Lotus 79 which refined the concept further. The '79 took American Mario Andretti to the title following year, but the successor car Lotus designed for 1980, the Type 80 was a lemon. Attempts were made to update the '79 but by this point all the other teams had caught them up, leaving Lotus uncompetitive. This was a position they did not really begin to recover from until the end of the ground effect era.
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| A drawing showing how Lotus first implemented, then refined the ground effect concept. |
The "wing car" design at first favoured the privateer teams and their Cosworth DFV V8 engines because these power plants were compact and allowed engineers to sculpt the airflow round the rear of the car more effectively than the likes of Ferrari with their bulky but powerful flat 12 engines. This ensured that the UK based, non manufacturer teams were able to hold the performance advantage over the works teams during the early years of the ground effect era, despite being well down on horsepower.
This situation began to gradually turn on it's head however with the arrival of Renault into Formula One in 1977. The French outfit pioneered the use of smaller, turbocharged V6 units that were even better suited to ground effect designs than the DFV. At first Renault had their hands full just stopping this engine from exploding after a few laps and it wasn't until 1979 that they managed to produce a ground effect car and marry it to an engine that could last a race distance. When Jean-Pierre Jabouille took pole at the 1979 South African GP then pole and victory at the French GP later in the season the writing was on the wall for the privately owned teams.
 |
| The Gordini V6 turbo engine mounted in the pre ground effect era Renault RS01. |
Ferrari soon followed Renault's lead and by the dawn of the 1980's the initiative was very much with the manufacturer teams again as turbo power was beginning to look like a pre requisite for success. Privateers were faced with the choice of find a manufacturer willing to build them a turbo engine or face being not competitive even with a ground effect car.
By late 1980 it was a clear case of the "haves" and the "have nots". The privateer teams began pulling all kinds of dirty tricks to level up what they saw as an unlevel playing field such as running their cars underweight. The FIA were also becoming concerned by the whole thing. Cornering speeds were becoming unacceptably high because of the increased downforce offered by ground effect cars. The dawn of the turbo era made it clear that this problem was only going to get worse. In addition to this the "wing cars" had a critical design flaw that could potentially prove fatal in the right circumstances.
If a ground effect car was to hit a kerb, or worse still the wheel of another car, the car would be lifted from the track high enough to break the suction underneath. Suddenly robbed of all of their downforce, these cars could then rapidly become airborne. Indeed the ground effect era saw several spectacular, aerial accidents which culminated in the death of Gilles Villeneuve and the career ending injuries of his Ferrari team mate Didier Pironi during the 1982 season. Something clearly needed to change as Rene Arnoux's accident at the Dutch GP in 1980 demonstrates...
The way the teams had been minimising the risk of loss of suction and increased overall downforce had been to use ultra stiff suspension to keep the cars as level as posible (and the drivers as uncomfortable as possible) and by fitting flexible rubber "skirts" along the edges of the sidepods. This stopped higher pressure air along the side of the car being drawn into the low pressure area underneath it and blunting the suction effect. These skirts moved up and now in relation to the sidepods as the cars went over bumps in the track to keep the seal tight.
The FIA saw this as the weak link of the design and started moves to limit the effectiveness of the "wing cars". For the start of 1981 these sliding skirts were banned and the minimum ride height of the cars raised with a view to reducing cornering speeds. However, the wording of the new regulations stated that the car need only be at this new ride height in the pits. Thus, it didn't take long for Brabham chief designer Gordon Murray to come up a hydraulic suspension system that could raise or lower the car's ride height depending on whether it was in the pits or not.
 |
| The 1981 version of the Brabham BT49 was fitted with underhand, but legal suspension. |
The rules quickly turned out to be unworkable and a compromise was sought for the remainder of 1981 and the following 1982 season. Skirts were allowed again, but only in a toned down "fixed" version and the ride height restrictions were removed.
From the beginning of 1983 the concept was banned entirely and cars reverted to a flat profiled undertray. This design remained in the rulebook until it too was deemed unsafe after the catastrophic 1994 season. There is something of a parallel between the dark years of 1982 and 1994. Both were set against a backdrop of uncertainty after hastily introduced rule changes designed to eliminate potentially dangerous technology from the sport. Both seasons featured the deaths of two drivers as a partial consequence of these changes.
If ground effect had continued to be allowed in the sport it would no doubt have brought about the earlier implementation of some form of active suspension system amongst the teams. The benefits of such a system were even more stark for ground effect cars than flat bottom ones and Lotus had begun experimenting with such a system as early as 1982. This would have raised the terrifying spectre of active ride ground effect cars running during the very height of the turbo era with all it's monster power excesses...
The ground effect era's most iconic car, the Lotus 79 in action.
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