Lotus 72

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Lotus

Lotus 72

1970 - 1975
Country:
United Kingdom
Engine:
Ford-Cosworth V8
Capacity:
2993 cc
Record:
20 wins from 75 races
Number Built:
9
Collectability:
5 star
Lotus 72
Reviewed by Unique Cars and Parts
Our Rating: 5

The Seven-Season 2.2-litre Formula



Colin Chapman and Lotus were, during their hey-day, arguably the most consistently innovative Grand Prix design and production team in motor racing history. The truly great cars of the post-World War 2 period can be counted on the fingers of both hands. The Alfetta, the Ferrari 500, the Maserati 250F, the Mercedes-Benz W196, the Vanwall, the Coopers which led the rear-engined way, and then the Lotus 18, the Lotus 25, the Lotus 49s which introduced the 'Ford' V8 engine by Cosworth, and then the Lotus 72 - all outstanding classics of their era, and four of the 10 by Chapman.

The Lotus 72 proved to be the longest-lived of the above mentioned, apart from the 250F which had the rare distinction of racing in both the first and the very last events of the seven-season long 2.2-litre Formula. Its story began in some ways not many months after the introduction of its super-successful predecessor, the Lotus 49, which was unveiled in that storybook debut victory at Zandvoort in 1967. At the end of that season Chapman and chassis designer Maurice Phillippe began puzzling out a turbine-powered car for Indianapolis, where Parnelli Jones had come within an ace of winning that year in Andy Granatelli's whooshmobile.

The result of their collective thought was the USAC Lotus 56, with Pratt & Whitney gas turbine power and four-wheel drive. The big problem with Indy had always been to persuade a car into the 250-270 km/h turns in a maintainably stable attitude. Earlier cars had pitched badly as the power was shut off, while all had aerodynamic lift problems at the 330 km/h straightaway speeds.

The Lotus think tank developed a simple wedge-shaped body form which combined the maximum negative lift force with a low pitching moment thereby reducing tail-end squat and front-end dive to a minimum and providing a stable platform. The smooth response and acceleration of of the turbine engine helped in this respect, but the behavior of the 56 spoiled Lotus's drivers when they returned to Formula One and the rorty, point-it-and-squirt, squat-and-dive antics of the Lotus 49.

Some experimentation was carried out with wedgy body styling on the 49B-series cars and on the four-wheel drive Mark 63s during 1969. Four-wheel drive as such proved to be a blind alley in Formula One terms, and so for 1970 Phillippe and Chapman put their heads together once more and evolved an outline for what was to become the Lotus 72. Between the Brands Hatch Race of Champions and the Spanish GP, the prototype Lotus 72 was shown to the press at Hethel. Lotus had set out to combine wedge aerodynamics with the standard Cosworth engine/Hewland gearbox two-wheel drive layout.

Coil-springs were ditched in favour of compound torsion bars at front and rear, consisting of an outer tubular section splined to a solid inner bar which passed back along the tube length to pick-up a suspension link. The tube end was itself rigidly mounted to the chassis frame and so a torsion bar of considerable effective length could be accommodated neatly in a single-seater hull. Rising rate geometry was used to progressively stiffen the spring as it was deflected, allowing very soft springs to be used without the penalty of bottoming on full tanks. In practice the springs automatically adjusted themselves to maintain constant handling characteristics whatever the car's state of load.

Suspension location was by conventional wishbones, mounted with a considerable anti-dive angle (front pivots lower than the rears) at the front end of the car, and with anti-squat (front pivots higher than the rears) at the back. This arrangement, it was hoped, would provide the required level ride characteristics, preventing the car dipping its nose under braking or squatting its tail under power. Both inadequacies reduced adhesion and cornering power at the opposing end of the car. To reduce unsprung weight, both front and rear brakes were taken inboard, operating on the inner ends of slender drive shafts passing out to the wheels, only the rears of course receiving power from the engine/ transaxle pack. The monocoque hull itself was a complex affair, full of compound curvature panels formed over steel bulkheads.

Cosworth V8 Engine



At the rear a Cosworth V8 engine was bolted rigidly to the rear cockpit bulkhead, and was employed as a fully-stressed integral chassis member carrying the rear suspension primary loads in the manner pioneered by BRM's H16 P83 design in 1966 and by Lotus' own Mark 49 in 1967. The monocoque was waisted amidships to feed air into a hip-mounted radiator pod on either side, the splitting and removal of the water radiator from its traditional position up front allowing a perfect chisel nose section to be employed, and further concentrating the car's mass about its true centre of gravity. Front canards were balanced by a three-section rear wing.

Lotus 72 in action at Brands Hatch Race of Champions
Lotus 72 in action at Brands Hatch Race of Champions.

Lotus 72 in action at Brands Hatch Race of Champions
Lotus 72 in action at Brands Hatch Race of Champions.

Ronnie Peterson - who had the greatest success with the Lotus 72
Ronnie Peterson - who had the greatest success with the Lotus 72.

Jacky Icks's finest hour with Lotus was during the Race of Champions, a non title event at Brands Hatch
Jacky Icks's finest hour with Lotus was during the Race of Champions, a non title event at Brands Hatch.

Jochen Rindt took the 72 out for a few brisk demonstration laps around Hethel's perimeter track. Braking into a corner the Lotus 72 just sat down, apparently glueing itself to the road ... it all looked good ... but it wasn't. The new car's debut came at Jarama, Madrid, for the Spanish Grand Prix on April 19, but during practice Jochen was braking hard for the tight right-hander past the pits when there came a loud thump and shudder from the new car's front end, and it pirouetted wildly down the road in clouds of rubber smoke!

The bolts holding one front brake disc had sheared due to the insulating spacer between disc and shaft overheating and breaking-up, leaving the bolts to fidget until they first stretched, then broke. Ventilated discs were hurriedly fitted to Rindt's 72/2 but no such spares were available for team-mate John Miles's 72/1 and it was scratched. Jochen Rindt lasted just ten laps in the race before the electronic ignition cut-out shorted. The new Lotus looked very soft, too softly-suspended in fact, and it was picking up its inside rear wheel under roll. Aerodynamic and suspension modifications were made before the International Trophy race at Silverstone, but Rindt's ignition went awry again and Miles's car broke an anti-roll bar in one heat and sheared-off its throttle pedal in the other.

For Monaco the team fell back on the trusty 49Cs (Jochen Rindt winning so sensationally in one after Jack Brabham shunted at the very last corner) while the 72s were torn down and reconstructed. Anti-squat angularity was removed from 72/2's rear suspension and the anti-dive removed from the front. This entailed unzipping the whole monocoque structure, and in fact 72/2 was reduced at one point to the seat tank and rear bulkhead structure, the whole monocoque being rebuilt from that point with different skins and forward sub-frame. The rebuild was programmed to last eight weeks - it took five. At Spa 72/2 emerged with parallel suspension, while 72/1 had the rear frame converted to remove its anti-squat. The larger job of removing the front anti-dive was side-stepped.

Maurice Phillippe regretted having adopted these features in deference - it seems - to Colin Chapman's wishes. He recalled how Cooper had toyed with the system in 1963 - 1964, and had bought themselves a similar parcel of trouble. The design emerged from all these changes at Zandvoort for the Dutch GP, where Jochen started from pole in 72/2 and won easily. For the French race at Clermont both 72s were considerably strengthened, with beefier subframes and suspension pick-ups, and Rindt won luckily. In Britain the 72s appeared with air-boxes feeding their injection systems, and again Rindt was astonishingly lucky to win - again at Brabham's expense as his BT33 ran out of fuel on the last lap when leading.

In Germany Jochen won genuinely after a race-long battle with Ickx's Ferrari but for his home race in Austria his engine failed. Miles, more seriously, had a front brake shaft shear but controlled the resulting moment to retire unhurt. These shafts were drilled internally to give some spring and reduce weight. Miles's breakage originated from a flaw on that drilling and so some stop-gap solid shafts were made up in time for the Oulton Gold Cup, where Rob Walker's long-awaited dark-blue '72/4' appeared for Graham Hill. Jochen Rindt won the second heat, and then came Monza. Trying too hard in practice, with zero wing, new and unscrubbed tyres and a braking ratio unadjusted to suit the new wing incidence, Rindt lost control under braking for the Parabolica and ploughed into a badly-installed Armco barrier - receiving fatal injuries as the barrier parted and his car was ripped apart by a floodlight stanchion.

His title was kept beyond Ickx's and Ferrari's reach by young Emerson Fittipaldi, who won the US GP in 72/5 which was provided new for him at Monza, and which he had damaged mildly in a practice crash of his own at the Parabolica turn. Reine Wisell, his new team-mate after John Miles's enforced defection from the team following Rindt's death, was third in 72/3, while Hill retired 72/4 - which was effectively 72/1 rebuilt and resprayed.

The 1971 Season



For the new season monocoques had to be reclad in 16-gauge outer skins as part of a CSI fuel tank protection programme. The low-level airbox with twin intakes either side of the driver's head was suspected of picking-up turbulence created by the mirrors, and from the 1971 British GP forward 'snorkel-type' airboxes were substituted, a la Tyrrell. Incidentally, Ken himself had a considerable effect upon the 72's development, for when overheating problems had been encountered at Jarama in 1970 their pods had been 'spaced' further away from the tub sides. In Austria that year Tyrrell protested the 72's hull width over these pods, and they were narrowed overnight. In practice next day the cars yielded an extra 200rpm on the straights! Ken said "Who needs an engineer to develop cars when they've got me?".

For the first time since 1959, Team Lotus went through the whole Formula 1 season without a single victory. Fittipaldi achieved one second, two thirds and a fifth place while Wisell scored two fourths, a fifth and a sixth ... but without a win nobody was happy. Emmo was hurt in a road crash in mid-season, and Chapman and Phillippe were spending time on road car production and the turbine 56B F1 car respectively. Everything was against continuing the 72's successful development with two young drivers inexperienced in Formula 1 racing, but then things changed during the winter.. .

The 1972 Season



In this year the John Player Specials were born, sprayed black and gold and carrying 'JPS' chassis plates with no concession to their Lotus parentage. Continual development saw the rear wings being moved progressively rearward, revised air boxes and oil tank fittings, and race-winning success. Emerson's faithful 72/5 was driven to victory by him in the Rome GP at Vallelunga, the Rothman's 50,000 Libre event at Brands Hatch over a full old-fashioned Formula One distance of BOOKms, and in the World Championship-qualifying Austrian and Italian PGs. A new car, 72/6, was built up for Reine Wisell's use from Nurburgring '71, replacing 72/3 which was sold to Dave Charlton in South Africa. It became Dave Walker's regular works car during 1972. Meanwhile the Rob Walker 72/4 was sold to Jo Siffert, who in turn wheeler-dealed it to Fittipaldi in November '72 to go on display back home in Brazil!

A new car for Emerson's use, 72/7, was completed in time for the Interlagos race in '12, and he used it to win the Race of Champions and GKN Trophy Silverstone non-Championship rounds, and the Spanish, Belgian and British GPS; nine F1 victories in the season - five at Championship level. Team Lotus, whatever their new guise might be, were flying high once more . . .

The 1973 Season



For the new season, from the Spanish GP forward, new deformable structure tank sheathing regulations came into force, and since Maurice Phillippe had flown the coop to work for Vel's Parnelli Jones in Caiiforr 5 Martin Waide became responsible for this extensive revision to the ageing but still competitive 72s. Ronnie Peterson was signed to join Emerson as joint number one in the Player team, anc with Firestone's reluctant dithering-about whether or not to continue -Formula One, Chapman signed with Goodyear. The change of tyre suppl'er dictated considerable suspension anc chassis development to compensate, anc while MelMag bonded wheels were adopted to save some of the inevitable weight added during all these developments they were to prove unreliable and in fact unsafe.

Ronnie Peterson got into the groove during 1973 to prove himself quite the fastest driver on the Formula One scene, but as he told me "I drive as hard as I can go, but it woss not until they make the car strong enough to stand up to it that I start to win races . . . and that woss a thing I thought woss never going to happen - it took so long ..." In fact Ronnie started from pole position in nine of the fifteen Championship rounds, but his failure in Spain was typical of his first half-season as Ronnie Peterson lost a fantastic 20-second lead to transmission failure. Meanwhile Emerson had begun his title defence very soundly, winning the Argentine and Brazilian GPs in 72/7, and stepping round his slowing team-mate to win the Spanish event in 72/5. He limped to the finish there with a tyre deflating rapidly to score Lotus' 50th Championship GP victory. They were the first marque to achieve the half-century in World Championship history, for Ferrari were hung up on 49 wins at the time, although they had scored pre-Championship GP victories in 1949.

Then in France Ronnie's car came good and proved strong enough to carry him to the line in first place. He won, in 72/6, and went on to score again in the Austrian, Italian and United States GPs. But his victory in Italy was controversial, for he raced Emerson to the line, pipping him by 0.8-second to rob the Brazilian of his last chance of retaining his World title. Chapman and team manager Peter Warr were condemned by Emerson's fans for not signalling Peterson to back-off. The Fittipaldi family stormed and raged. Chapman stayed out of the way . . . while Ronnie just said nothing but smiled. Emerson's masklike concentration had begun to crack-up in mid-season, as at Ricard when Ronnie scored his first win while Fittipaldi crashed over Scheckter's McLaren wheels.

The 1974 Season



Both 72/6 and 72/7 were sold to the South African Winston Tobacco Company for national racing at the end of '72 and the new JPS9 10 or Lotus 76 cars were produced to replace the now over-developed, and overweight 72s. They proved an abject failure, and Ronnie returned to 72/8 which had been new for him in Buenos Aires the previous season but which he had set aside in favour of old 72/6. With the later car he put up those incredibly diverse but classical drives to win at Monaco, Dijon (in the French GP) and again in the Italian GP at Monza.

Ronnie's new team-mate, Jacky Ickx, was going off the whole idea of Grand Prix driving during this season, but his performance to beat Lauda in the rainy Race of Champions at Brands Hatch was brilliant, particularly when his car - the re-tubbed 72/5 - passed Niki's Ferrari round the outside of the downhill Paddock Bend.

The 1975 Season



The 1975 Formula One season, for the Lotus 72, is really best forgotten. At long last the 72, designed so long ago, was totally obsolete. Its after-thought deformable structures, its yards and yards of oil pipe, water hose, fuel lines, all were overweight results of piecemeal development on a basic chassis which would not have been built the way it was if now-current regulations had all been in force back in 1970. A "new" car, 72/9, was conjured up for Ronnie Peterson, but the Team's 29 starts yielded only 15 finishes, Peterson scored just six Championship points, and Ickx bowed out to await the new Lotus 77 ... he thought.

Chapman gave Brian Henton, Jim Crawford and John Watson drives in his obsolete cars, and efforts were made to improve their performance with a cable-link replacing rigid push-pull rods on the rear torsion bars, then coil-springs replacing the coils altogether, an extra-long wheelbase arrangement, slave coil-springs on the front-end and numerous other tweaks. Finally all was returned to standard form, and Ronnie charged home into fifth place at Watkins Glen after running fourth at one point. Basically the Lotus 72 could no longer exploit, nor indeed extract, the full potential from Goodyear tyres designed for lighter, but stiffer cars, and with Ronnie's great charge in America the long, long saga of the Lotus 72 finally came to an end.
Lotus 72 at the Brazilian GP in 1974, Jacky Ickx at the wheel
Lotus 72 at the Brazilian GP in 1974, Jacky Ickx at the wheel.

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