No. 33 The Lo­tus 79

Not the first car to embrace ground ef­fect – but the first to get it right

F1 Racing - - FINISHING STRAIGHT -

There’s an old en­gi­neer­ing maxim that if some­thing looks right, then it is right. The Lo­tus 79 must surely be one of the best-look­ing grand prix cars of all time; wide, low, per­fectly pro­por­tioned, un­fuss­ily de­tailed – and, on track, ut­terly dev­as­tat­ing.

The 79 wasn’t the first car to make use of ground ef­fects to boost cor­ner­ing grip – that ac­co­lade goes to Can-Am racer Jim Hall’s Cha­parral 2J, which used a pair of fans to suck air from un­der the car (an idea later res­ur­rected in F1 by Gor­don Mur­ray for the short-lived Brab­ham BT46B fan car). But it was the first to get it right.

Lo­tus founder Colin Chap­man spent much of the 1970s look­ing for the next big tech­ni­cal step that would de­liver a crush­ing on-track ad­van­tage. But time and again he ex­pended his en­er­gies in the wrong di­rec­tion – ei­ther on tech­ni­cal dead ends in F1 or by be­com­ing dis­tracted by his grow­ing road-car op­er­a­tion. By 1976, his de­sign team had failed to come up with a cred­i­ble suc­ces­sor to the 72, a ti­tle-win­ning car in 1970 and 1972, but now long in the tooth.

Lead driver Mario An­dretti pro­nounced their 1976 car, with its com­plex multi-ad­justable sus­pen­sion, “a dog”. This prompted Chap­man to look to aero­nau­tics: he grew fas­ci­nated by the idea of us­ing an up­turned air­craft wing pro­file to cre­ate the op­po­site of lift. Lo­tus en­gi­neers Tony Rudd and Peter Wright had ex­per­i­mented with the idea while work­ing for BRM, but had to drop it due to a lack of re­sources. With Chap­man’s back­ing they got time in a wind­tun­nel at Im­pe­rial Col­lege to prove the con­cept of shap­ing the un­der­body to cre­ate down­force. Here serendip­ity played its part: the ba­sic wind­tun­nel model, made from balsa wood and card­board, be­gan to sag as the low-pres­sure area un­der the car took ef­fect. The nearer the outer edges of the side­pods got to the ‘ground’, the greater the ef­fect.

Thus the Lo­tus 78, which made its de­but at the first race of 1977, fea­tured full-length side­pods con­ceal­ing in­verted wing pro­files within, plus slid­ing skirts on each side, which sealed the gap be­tween the car and the track. It no­tice­ably bucked the trend for short side­pods, but even so ri­val teams could not fathom the car’s ad­van­tage.

The 78 won five races in 1977 in the hands of An­dretti and Gun­nar Nils­son, and a fur­ther two in 1978 be­fore it was re­placed by the 79. The new car built on the strengths of the 78 and sought to elim­i­nate its faults, chiefly poor re­li­a­bil­ity, stem­ming from a chas­sis that wasn’t strong enough (due to Chap­man’s fix­a­tion with low weight), and an aero­dy­namic cen­tre of pres­sure that was too far for­ward.

Fi­ness­ing the ven­turi within the side­pods, and pack­ag­ing them so the rear sus­pen­sion didn’t in­ter­rupt in­ter­nal air­flow, yielded so much more down­force that the 79’s chas­sis had to be strength­ened fur­ther, con­tribut­ing to its de­layed de­but. An­dretti and team-mate Ron­nie Peter­son scored four one-twos be­fore Peter­son’s fa­tal ac­ci­dent. An­dretti won the driv­ers’ ti­tle, with Peter­son a post­hu­mous sec­ond.

The 79’s suc­cess led Chap­man to pri­ori­tise down­force on the Lo­tus 80. The more aero-ef­fi­cient Wil­liams FW07 – based on the 79 – took the ti­tle in 1980, and Chap­man never again saw such dom­i­nance.

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