The Lotus 79 is a Formula One car designed in late 1977 by Colin Chapman, Geoff Aldridge, Martin Ogilvie, Tony Rudd and Peter Wright of Lotus.

The Lotus 79 was the first F1 car to take full advantage of ground effects aerodynamics, pioneered in its immediate predecessor, the Lotus 78. The undercar pressure problems in the 78 were resolved with the 79, with further design work on the venturi tunnels under the car, which allowed the low pressure area to be evenly spaced along the whole of the underside. This was achieved by extending the rear bodywork to a point inside the rear wheel suspension system, allowing the underside to extend further back, instead of ending abruptly in front of the rear wheels as on the 78. As a result, the rear suspension was also redesigned to allow the air to exit the rear more cleanly than on its predecessor. This allowed a smaller rear wing to be used, lowering drag. When the car first appeared, the upper bodywork was steeply raked and featured "Coke bottle" sidepods. After work in the wind tunnel, these features were found to be unnecessary, as the car generated so much downforce anyway. These features were, however, later incorporated into the Lotus 80. In all, five chassis were built during the design's lifetime, with the prototype 79/1 later sold to Héctor Rebaque to race as a privateer entrant.

The car was powered by the Ford Cosworth DFV and constructed of sheet aluminium honeycomb, specially strengthened for the pressures exerted on the car by the ground effect. The fuel tank was one single cell behind the driver, as opposed to the separate fuel tanks on the previous Lotus 78. This had the advantage of increasing fire protection and returning the centre of gravity to the middle of the car, helping cornering and braking. The 79 was also the first F1 car to be designed using computer design aids.^{[citation needed]} In fact, it was the first F1 car to use computers to analyse it in the pits on race weekends.

The car was secretly tested in late 1977 by Ronnie Peterson and proved extremely fast, but the chassis suffered early fatigue due to the severe suction and g-forces generated by the ground effect. The 79 produced about 30% more downforce than the 78, something not foreseen by Ogilvie and Rudd, who went back to the drawing board. The chassis was strengthened in specific points, mostly around the monocoque and load bearing points on the chassis tub, and the car was found to be even faster than before.^[3]

The need for smooth airflow dictated the car must have clean lines. Nicknamed "Black Beauty" by the press and F1 fans alike, for its graceful design and sleek profile and its black and gold livery through sponsorship by John Player Special cigarettes, the Lotus 79 was instantly competitive on its debut, the 1978 Belgian Grand Prix at Zolder. It took the pole position at the hands of Mario Andretti by more than a second, and went on to win the race comfortably. Andretti said after driving the 79 for the first time that, in comparison, the Lotus 78 was „like driving a London bus“. Peterson once quipped, after scoring an impressive pole position, that the car was so brilliantly set up, all he had to do was steer.^[4]

The 79 was not without its problems, however. Wright and Ogilvie noted that the car was very marginal in some aspects of its design. Andretti had reservations over the car's brakes, which faded noticeably over a race distance, especially in hot conditions; the exhaust had a tendency to overheat, and the monocoque tub was not as stiff as the team would have liked, which meant a new casting had to be fabricated several times during the two seasons the car was used.

The 79 proved to be almost unbeatable during the 1978 Formula One season and provided an unprecedented level of domination, the team had already won in Argentina with Andretti and South Africa with Peterson. The 79 was first used during practice for the Monaco Grand Prix with Mario Andretti driving but he used the 78 in the race. The 79 was ready for the following round in Belgium with one car available for Andretti with Peterson using the older 78, the pair finished first with Andretti and second with Peterson. Same results in the same order at the Spanish Grand Prix as both drivers had exclusive use of the 79. The Swedish Grand Prix caused anger from several teams including Lotus because Brabham had redesigned their Brabham BT46B which was known as the "fan car". Andretti took pole and led till Niki Lauda's fan car passed him, Andretti would have his engine blow up and Peterson finish third behind Lauda and Riccardo Patrese's Arrows. After the race, Brabham voluntarily withdrew the BT46B.  The 79 was first and second at France with Andretti first and Peterson second. The 79 had a double retirement at the British Grand Prix with Peterson retired from second place after seven laps with a fuel leak, Andretti led until lap twenty four when he pitted with a left rear puncture and whilst chasing the leading pack he blew his engine up. In Germany Andretti won but Peterson retired when his gearbox failed, the Austrian Grand Prix saw Peterson win but Andretti retired after he tried to pass Carlos Reutemann's Ferrari and the two touched with Andretti car spinning into the barriers. Holland was the last first and second for Lotus in its career with Andretti first and Peterson second. The Italian Grand Prix was a weekend to remember for all the right and wrong reasons for Lotus, Andretti qualified on pole but Peterson qualified sixth and had to use the older 78 after the 79 had sudden brake failure in the warm-up plus he was unable to fit into Andretti's spare car. The start was chaotic with Andretti being passed by Gilles Villeneuve's Ferrari and Lauda's Brabham. Peterson had a poor start plus bunching around him caused a collision between him, Patrese's Arrows and James Hunt's Mclaren. Peterson's car caught fire and Hunt dragged the Swede free and laid in the middle of the track fully conscious, but with severe leg injuries. Peterson had an operation and would die on the Monday after the race. Andretti would take the restart and would be first on the road but finished sixth after he and Villeneuve both jumped the restarted race. Jean-Pierre Jarier took over the second Lotus in the United States and was running third till he ran out of fuel with four laps to go, Andretti led for the opening laps but he had a brake issue and later on his engine blew. The Canadian Grand Prix had problems for Andretti as he attempted to pass John Watson's Brabham and the two made contact dropping the American almost right to the back of the field and finished tenth. Jarier took pole and led until an oil leak. It proved that even with a lesser driver that the 79 was still competitive.

The Lotus 79 was so dominant the only real threat was the Ferrari 312T3, and the advantage its Michelin tyres gave in hot weather conditions. Its other threat was the Brabham BT46B "fan car" but Brabham withdrew it after its victory in Sweden. Meanwhile, the Ferraris only won when the Lotus failed to finish. So superior was the Lotus, that most races became a scrap for minor placings, as Andretti and Peterson regularly finished first and second, more often than not by a considerable margin ahead of the rest of the field. On the rare occasion the 79 did not win or fail, one or other driver was usually on the podium. Andretti was comfortably world champion in 1978 and Peterson finished runner-up posthumously; Lotus won the constructors’ championship with 86 points.

Jean-Pierre Jarier took pole position for the 1978 Canadian Grand Prix and was leading the race until lap 48 when the engine oil pressure drop has forced him to retire from the race.