Revolutionary Technology in Formula One – Ground Effect

The development of the downforce-generating wing changed the course of Formula One forever, requiring a complete change in driving style and car construction to make the most of the generated downforce. No longer could drivers use flashy but inefficient drifting moves around corners; instead, precision became more and more of a factor. The generation of downforce by the wings of the car improved lap times as the tyres were used more efficiently, but there seemed to be an upper limit on how much downforce could be generated by a car’s wings before the drag effects of the wing cancelled out improvements in lap times by increasing downforce. Some enterprising team managers looked for new ways to generate downforce, ones which wouldn’t lead to drag effects cancelling out their hard work.

Just as the downforce-generating wing had been derived from aeronautical engineering, so too was the next development in downforce generation, and just Colin Chapman, legendary team owner, manager and engineer of Team Lotus, had been involved in the development of the wing, so he was instrumental to the development of automotive ground effect in Formula One. However, just as with the downforce-generating wing, the development of ground effect first came from a source outside of Formula One. Jim Hall, the Texan racing driver responsible for the Chaparral cars which had heavily influenced the development of the wing in Formula One, had also preempted developments in ground effect with the Chaparral 2J.

The Chaparral 2J was a bizarre-looking car, with a distinct and unmistakable boxy shape which seemed to completely defy all of the conventional logic on automotive aerodynamics. However, the 2J came with its own secret weapon. Two fans, driven by a two-stroke snowmobile engine mounted in the car, “sucked” the car to the surface, while flexible plastic skirts fitted to the underside of the car maintained a semi-vacuum seal which helped maintain the generated downforce from the two-stroke-driven fans.

The 2J caused great controversy in the Can-Am series in which it competed, with competitors complaining of stones thrown back by the suction fans into the faces of following drivers. The McLaren team, then dominant in the series, launched a complaint which sought to ban the fans under a law prohibiting “moveable aerodynamic devices”. Despite its significant advantages, including downforce which did not fluctuate based on the speed of the car, the Chaparral 2J was not competitively successful and suffered problems with reliability. While the 2J was capable of racing at two seconds a lap faster than its competitors, this meant little if it could not finish a race. The car raced for a single season of Can-Am in 1970, before the successful upholding of McLaren’s complaints led to the car’s banning.

The Chaparral 2J may not have been competitively successful, but other designers were researching similar concepts at the same time, trying to reduce effects such as turbulence caused by their early aerodynamic wing structures. Gordon Murray of the Brabham team managed to create useful downforce in the mid-1970s by strategic placement of air dams under the car in an attempt to prevent air flow under the car. However, like many of the developments in Formula One, Lotus were themselves doing research into the field of under-car aerodynamics.

In 1976, confronted with sub-par performance from their Lotus 77, having developed it as a replacement for their long-running and successful Lotus 72 which had nevertheless grown long in the tooth, Team Lotus redoubled their efforts on a new car. Colin Chapman, who had studied the de Havilland Mosquito fighter-bomber, one of the quickest and most successful aeroplane models of the Second World War, had realised that the wing-mounted radiators had been designed in such a way to develop lift. This, Chapman realised, could be developed in reverse in order to generate downforce, in much the same way that a reversed wing structure was then generating downforce for Formula One cars.

Having struggled in 1976 with only a single win throughout the season, Lotus fought back in 1977. The Lotus 78 was, when it worked correctly, utterly dominant, winning five races and raising Lotus from a distant fourth in the Constructors’ Championship in 1976 to second in 1977. The car owed its spectacular speed to the careful sculpting of the car’s sidepods in a way resembling an inverted aerofoil, thus creating an area of low pressure underneath the car and generating additional downforce, similar to the already-existing wings. As with the Chaparral 2J, the air was sealed under the car by the use of plastic skirts, which also had the side-effect of making it difficult for other teams to figure out where Lotus’ sudden jump in pace had come from.

Unfortunately for Team Lotus’ quest for both championships, however, the usual unreliability for Lotus cars seems to have taken hold in 1977 and despite the obvious pace, Niki Lauda’s superior reliability in the Ferrari was enough to stave off not only the challenge of Mario Andretti in the Lotus 78, but also Jody Scheckter’s challenge in the surprisingly quick car of the Walter Wolf Racing team. These reliability issues were a consequence of development versions of the Ford Cosworth DFV that was used in the Lotus 78 in an attempt to gain back some of the speed lost by some design faults of the car that caused oversteer and required a larger, drag-causing rear wing.

Nevertheless, the pace of the Lotus 78 when it went well was cause for hope and Team Lotus continued with the car into 1978. Meanwhile, the team were preparing their follow-up effort, but before this was introduced, the Lotus 78 still proved fast enough to win two of the first five races of the season, one each in the hands of Mario Andretti and Ronnie Peterson. It was after the fifth race had concluded at Monaco, however, that Team Lotus would introduce their new car, one that would prove to be as dominant in 1978 as the Lotus 78 had (on the occasions when it managed to finish) in 1977.

The Lotus 79, the first Formula One car to be designed using a wind tunnel and computer-aided design, was one of the biggest jumps forward ever seen in Formula One. If the Lotus 78 had been the revolutionary design, demonstrating what ground effect could do to the performance of a Formula One car, the Lotus 79 was the deep refinement of those principles and would overwhelmingly give Lotus both the Drivers’ Championship and Constructors’ Championship in the most dominant style then seen in Formula One. The Lotus 79 would take a further six wins for Team Lotus throughout the remainder of the season, including five for Mario Andretti on his way to the Drivers’ Championship.

The only realistic competitors that Lotus had during 1978 were Ferrari, whose 312T3 model was set up well for its Michelin tyres in hot weather conditions and Brabham, who picked up scraps in most of the races, but had one notable success in the Swedish Grand Prix. In this race, the Brabham team introduced their BT46B model, otherwise known as the “fan-car”. Gordon Murray had figured out how the Lotus team were achieving their outstanding pace, but with a car with a wide flat-12 engine which was unsuitable for manipulating the undersides of the car, the Brabham team decided to try something different.

In much the same way as Jim Hall had done with the Chaparral 2J, the Brabham BT46B developed downforce by the use of a fan fitted at the back of the car to create a partial vacuum. The results were staggering, the Brabham team cantering to an easy win, leaving even the Lotus cars in their wake. Some sources have even suggested that the Brabham cars were deliberately driven slower than they could be in order to create a semblance of fair play. In either case, the win created uproar in the paddock and fan cars were soon declared illegal from then on, with Brabham’s win still standing.

Unfortunately for Lotus, their outstanding success in 1978 was marred by the death of Ronnie Peterson near the end of the season at Monza during the Italian Grand Prix. A midfield pileup at the start of the race caused Peterson to crash with severe leg injuries. Unfortunately, as he was not judged to be in as much danger of death as others that had been injured in the shunt, he was not examined as thoroughly as he possibly should have been and later died of fat embolism in hospital. This put a damper on the celebrations for Team Lotus and Jean-Pierre Jarier was drafted in to compete in the remaining races.

After such a dominant performance, it could hardly be expected that Team Lotus would never win another championship, but 1979 was not a successful year for the team. The Lotus 80, which was to be used in the 1979 season, did not prove successful, suffering from an excess of downforce along with an effect known as “porpoising”, where the low-pressure area generated by the ground effect was moving around with the car’s centre of gravity. Indeed, this would prove to be a problem with other ground effect cars designed by less well-funded teams.

The Lotus 79 was drafted in to compete in the season, but the secret of Lotus’ success was out and other manufacturers had improved on Lotus’ designs to create ground effect cars of their own. Of these, Ferrari would be the most successful, despite their large flat-12 engine which, as with the Brabham BT46, made manipulation of the car’s underside difficult. Winning six races and scoring several podiums, Ferrari were the dominant team during 1979. Meanwhile, Team Lotus, who had dominated the 1978 season, were pushed back down to fourth place in the Constructors’ Championship, behind Williams and Ligier.

Ground effect would therefore become a constant element of Formula One cars in the next few years, but it came with its downsides. As the cars grew faster, the g-forces on the drivers grew stronger, making them less and less comfortable. Improperly understood, ground effect could cause alarming effects such as the aforementioned “porpoising” problem. With the development of turbocharged cars in the early 1980s, the cars threatened to become even faster – and would once the reliability issues were resolved – which gave the frightening notion of twitchy cars with a lot of power behind them.

Eventually, things came to a head. The 1982 Formula One season was one of the most unpredictable and tragic seasons of Formula One ever, with two drivers dead, several others injured and several dangerous incidents which could be attributed to the sudden loss of downforce when a ground effect car went over the kerbs. While neither of the deaths could be attributed to these effects – Gilles Villeneuve lost his life after a horrible crash in qualifying while chasing down his teammate’s time after the incident at the San Marino Grand Prix, while Riccardo Paletti was the victim of a start-line incident where he hit Didier Pironi’s stalled car from behind and was left stuck in a burning car when the fuel tanks suddenly went on fire – there was a sense that the season had shown too much danger and ground effect cars were promptly banned for the following seasons, being replaced with cars with flat undersides. The 1983 season would be won by a dart-shaped Brabham BT52 which starkly contrasted with the wide, squat ground effect cars of the previous years.

Today, the laws against ground effect in Formula One are strongly upheld with the addition of a wooden plank underneath the car. This is not permitted to wear down past a certain depth, effectively mandating a minimum ground clearance. However, even with the flat undersides, teams still manage to get some degree of downforce by air flowing under the car; with careful shaping of the rear diffuser and the car’s bodywork at the back, downforce can still be gained. While some racing series other than Formula One have used ground effect themselves, it would remain to be seen how much faster the Formula One cars of today would be – and how much less comfortable to drive – if ground effect had not been made illegal.