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Tech Insight: What Is Ground Effect & Will Low Skirts Return?

Ground effect is a concept created in a bygone era between 77′ and 83′. A return would see dramatic improvements in lap times and less dependence on aero. Should it return in 2017? The Lotus Type 78 introduced a new innovative era of Formula One, when Colin Chapman saw fit to essentially turn the body of a Formula One car into a downforce inducing aerofoil itself. Cars before this generally created downforce, through the use of front and rear mounted inverted aerofoils. The first wings used were relatively primitive in comparison to what we see today, although they were still just as integral to providing downforce.

The ground effect concept was stumbled upon, almost by complete accident, by Peter Wright at Lotus. He was testing different underbody shapes in their wind tunnel when he noticed that when speed increased with one of the shaped floors, it was creating such phenomenal amounts of downforce that the wind tunnel model was being pulled closer to the floor. He immediately presented the discovery to Lotus chief Colin Chapman who gave his design team free rein to develop the concept and produce a chassis utilising the discovery. This ultimately resulted in the birth of the Lotus Type 78 in 1976. However, Chapman was reluctant to introduce the car mid season in case other teams discovered their latest quantum leap in Formula One aerodynamics, and so the Type 78 was introduced in the 1977 season and witnessed the dawn of a new era in Formula One.

The concept that Lotus had discovered was relatively simple when looked at retrospectively; it employed the use of mounting aerofoils inside the side pods attached to the chassis of the car. This, in turn, created a chassis that generated downforce without the use of mounting wings at the front or rear of the car. Teams soon followed suit up and down the pit lane, often with incredibly low skirts. Conveniently, these hid the internal aerofoils, but more crucially they prevented the air flow underneath escaping and keeping the ‘ground effect’ car effective – they were integral in maintaining low pressure. These factors all came together to assist channelling the air under the car with little drag or bleeding to create monumental downforce likened to that of a suction pad.

IMG_3660 (1)
Seb Scott/FormulaSpy

The basic chassis, with a cutaway view into the left sidepod, showing the integrated aerofoil and air flowing underneath it.

Seb Scott/FormulaSpy
Seb Scott/FormulaSpy

Sketch of a side view here, showing a generic car from the ground effect era. Note the scale of the side pod aerofoil, in comparison to the rear wing aerofoil, and how low the skirts are to the ground. These are highlighted in the peach coloured area. The main aerofoil highlighted in yellow is of solid construction, as you can see the airflow wind its way around the main profile of the wing. Unlike the aerofoil, the side pod itself consisted of sheets of fibreglass, riveted to the out board side of the aerofoil to form the skirt. This construction forms a tunnel running underneath the side pods allowing air to flow under and then follow the profile of the underside of the airfoil to generate huge amounts of downforce. Along with this, downforce was still created with the rear wing too; however, many teams in the ground effect era actually opted to run without front wings as they would hinder downforce generated under the car.

So what does this have to do with 2017?

Formula One has an inherent problem now which has seen overtaking become increasingly difficult without the aid of devices such as the Drag Reduction System which was controversial when introduced. This only means though that overtakes are concentrated in DRS zones. The Strategy Group has been looking to cut lap times by a considerable chunk to bring cars back to the speeds last witnessed in 2004, but also to create more overtaking opportunities on track.

The largest contributing factor towards the lack of overtaking, even on straights, has actually been due to the complexity of the front wings and their influence on the performance on the rear of the car in terms of aero. When a car is following closely to another, they’re unable to keep up through corners. This is due to the lack of clean air which is needed for air to flow to the rear of the car via the front wing in order to maintain high levels of downforce and therefore grip.

One idea that has been touted is to reduce the complexity of the front wing but this would only reduce the speed of the cars even more and wouldn’t help Formula One work towards achieving its goal of slashing lap times.

A solution to this is to allow the use of ground effect floors again, but to use a spec floor from a sole supplier in order to reduce costs and maintain a level playing field. More importantly though, the key to a spec floor would be to keep the cars at safe speeds as were seen in the ground effect era. The cars between 77′ and 83′ started to reach eye blurring speeds around corners with the aid of turbo chargers and as a result of the even higher speeds, accidents were becoming described as near death experiences. This prompted FISA (then equivalent of FIA) to step in and flat floors were introduced.

If ground effects were to return to Formula One, speeds would be increased dramatically at very little extra cost. Overtaking should improve, or at least more opportunities would arise. We would be entering an era of incredibly technically innovative cars, where we could be faced with extra grip from wider tyres, more powerful ‘1000bhp’ engines and the return of ground effect. For a little taste of what a modern Formula One car could look like, let’s apply the designs of old to the chassis of anew, with a couple of tweaks which could see a dramatic improvement in aerodynamic performance without really transforming the looks of Formula One Cars today.

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Seb Scott/FormulaSpy

As you can see much of the shape of the car would remain the same, with longer side pods, a lower floor, a lower beam wing, and a simpler front wing element. Most notably, as can be seen here in this cross sectional sketch an integrated aerofoil within the long, low skirted side pod, which would in turn feed airflow towards the beam wing. The airflow is also blown by exhaust gases where you can see the exhaust outlet near to the rear wheel and trailing edge of the ground effect aerofoil.

About Seb Scott

Sebastian is an FIA accredited Formula One journalist and Motorsport engineer. He lives and breathes Formula One, especially the technical aspect of the sport. For a unique insight behind the scenes at a Grand Prix, especially tech related pictures, check out his twitter @sebscottf1

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  • otto

    A cheaper and simpler way to bring back the speed and the passing with better looking cars? What is this voodoo?

    Of course since this is a simple and straightforward method with plenty of history to support it’s return, we can rest assured that the current management in F1 will be dead set against it and will instead devise the most expensive and complicated solution filled with ever more ridiculous gimmicks like crappy tires, DRS, and fake drama. They will pour billions of dollars into a formula no fan wants, then sit there dumbfounded as the fans continue to disappear.

    You can always count on F1 to make the wrong decision at the worst possible moment. They wear incompetence as a badge of honor. This idea has absolutely no chance of seeing the light of day simply because it makes sense.

  • Guillermo De Simone

    I believe rethinking the tyre policy with many manufacturers and less graining is far more important than ground effect. Today cars are reaching 6G at Spa and there is not much downforce to apply without harming the drivers. Pat Symonds said something very clever: it´s not the cars speed but the rules that make the race not a predetermined result.