The first Formula 1 car to adopt the aerodynamic feature known as "ground effect" was the Lotus 78 in 1977. Designed in 1976 by Colin Chapman's Lotus Cars, the car was conceived around mid-1975 when Chapman tasked a team of British engineers, Tony Rudd, Peter Wright, Ralph Bellamy, Martin Ogilvie, and Charles Prior, with designing a car featuring innovative and revolutionary aerodynamics for the time.
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| LOTUS 78, Mario Andretti Monza, Italian GP 1977 |
The idea itself was relatively simple and originated from Chapman: applying the same downforce principle used by the front and rear wings to the car’s body. The Lotus design team began theoretical studies to apply an inverted wing profile under the side pods, aiming to generate high downforce. A 1:25 scale model was built with a concept drastically different from previous F1 cars. Instead of having a flat underbody, the Lotus 78 featured large side pods shaped underneath like an inverted wing, hence the term "Wing Car." These side pods tapered towards the ground up to about halfway through the car before gradually widening again toward the rear diffusers. The Lotus 78 had large, elongated side pods, housing ducts that enabled the ground effect, also known as the Venturi effect, a phenomenon discovered by Italian physicist Giovanni Battista Venturi in the late 18th century.
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| LOTUS 78, Mario Andretti Long Beach, USA West GP 1977 |
The air entering the large front intakes was compressed and accelerated due to the narrowing of the central section, before being expelled by the rear diffuser, creating a strong low-pressure zone that significantly increased downforce. Unlike the downforce generated by wings, which increases aerodynamic drag, Venturi-generated downforce had minimal impact on drag, allowing the car to be much faster in corners without sacrificing top speed on straights. To maximize space beneath the side pods, the fuel tank was moved behind the driver’s seat, and the radiators were repositioned to direct airflow upward, preventing disturbance in the low-pressure area. A significant challenge arose: sealing the edges of the side pods to prevent air leakage, which would weaken the ground effect. A solution came from Jim Hall, designer of the Chaparral 2J (1970), a car that used a rear fan to extract air from underneath, creating suction. Instead of a fan, Peter Wright equipped the Lotus 78 with nylon side skirts that lightly brushed against the asphalt, sealing the Venturi ducts under the side pods.
LOTUS 78, Gunnar Nilsson
Monza, Italian GP 1977
On paper, the concept worked flawlessly, but when tested on track in late 1976, several minor issues emerged. Colin Chapman decided to postpone the car’s race debut to the 1977 season, convinced that once the initial teething problems were solved, the Lotus 78 would be a revolutionary and unbeatable car. The main issue was weight distribution. With large side pods housing the radiators on top and a narrow front section designed to channel air into the side pods, the car suffered from instability due to a high center of gravity. Over time, weight distribution was improved through modifications. Another problem was the nylon skirts, which were too flexible and deformed under air pressure, compromising the Venturi seal.
LOTUS 78, Mario Andretti
Montecarlo, Monaco GP 1977
The solution was to replace them with rigid ceramic skirts, supported by preloaded springs embedded in the side pods, which pressed the skirts against the asphalt, ensuring a perfect seal. With increased cornering grip, John Player Team Lotus drivers Mario Andretti (Italian-American) and Gunnar Nilsson (Swedish) gained confidence in the car. Just three races into the 1977 season, they scored the first victory, returning Lotus to the top of F1. The Lotus 78 secured five victories that season, finishing 2nd in the Constructors' Championship and 3rd in the Drivers' Championship with Andretti. Despite its early flaws, the Lotus 78 demonstrated immense potential and was soon copied by all rival teams.
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