The Indianapolis Lotus 29
While at Indianapolis last year, driving a Mickey Thompson car with rear-mounted V8 Buick engine, Dan Gurney had the idea that Colin Chapman could build a car that could win the famous 500-mile race. Gurney bought Chapman a round-trip air-ticket to visit Indianapolis for the day of the race, to see what went on, and afterwards they hatched their plot. Chapman specified an engine of 350 b.h.p. on petrol, weighing 350 lb. all on, and visualised mounting it in an enlarged Grand Prix Lotus weighing a lot less than the average Indianapolis racing car, so that it would run the 500 miles with only one stop for fuel and tyres.
Gurney then took him along to the Engine Division of the Ford Motor Company in Detroit and they explained their requirements. By this time racing and competition activity by Ford was beginning to appear in all sorts of ways and more and more openly factory-sponsored. They agreed to supply engines giving 1 b.h.p./lb. weight, by building special aluminium 4.2-litre versions of the Fairlane V8, the maximum permitted at Indianapolis. So keen were Fords on the Lotus-Ford project that they wanted to supply Chapman with V8 engines having overhead camshafts, fuel-injection and running on alcohol, promising 450 b.h.p. total, but the Lotus designer insisted on simplicity and plumped for push-rod o.h.v., Weber carburetters, and straight 100-octane petrol, the elimination of pit-stops being of prime importance.
Early in 1963 the project was under way, the plan being to build a prototype car early in March, take it to Ford’s testing ground in Arizona to get things sorted out and then build two brand new cars for the actual race and qualifying runs. Naturally Gurney was to be one of the drivers, and Jim Clark was to be his team-mate, and after the United States G.P. in October 1962, Team Lotus went to Indianapolis with a Lotus 25, the actual car used at Watkins Glen, and Clark put in some familiarisation laps at around 142/143 m.p.h. and took his “track-test.” By the beginning of March 1963 the Team Lotus mechanics were working almost non-stop to complete the prototype car, known as the Lotus 29, the chassis being an identical “monocoque” stressed aluminium sheet structure as used on the Lotus 25 Grand Prix car, and suspension front and back also being as on the Lotus 25.
Ford supplied the first V8 engine which weighed 370 lb. complete, but was already giving 370 b.h.p. on petrol, so the power-unit aim was achieved, and this was mounted on the rear of the “monocoque” structure, just as the Coventry-Climax V8 is on the Grand Prix car, and coupled to it was a new design of 4-speed Colotti gearbox and final drive unit. With four swept-back stub exhaust pipes on each side the appearance was pretty formidable and the noise such that even the Team Lotus mechanics were embarrassed when it was first started up in the road outside the Cheshunt factory.
From a distance the resulting car could easily have been taken for a Formula One Lotus, but closer inspection showed that it was slightly bigger in all directions by about 10%, but was still remarkably small and compact for a 4.2-litre car. This first car 29/1 was in the nature of a mock-up and had normal G.P. suspension parts, bolt-on wheels and many other features of a temporary nature, and after a brief run at Snetterton, with Clark driving it, it was flown to Los Angeles where Gurney collected it and took it to the Arizona proving-ground. Chapman, Clark and the mechanics flew out directly and testing began, to find out about radiators, oil coolers, temperatures and general engine installation problems and meanwhile Fords were doing a great deal of development work on further engines.
Following the Arizona testing the team went to Indianapolis and tried the car round the famous track, but unfortunately went a bit quicker than they intended, so that all the opposition became acutely aware that Chapman and Ford were not there for fun, as Cooper and Brabham had been previously, but were there to win. Gurney was timed at laps around 150 m.p.h. and while doing these speeds Fords installed an electronic recording instrument in the cockpit which plotted a trace of throttle position against time, and recorded continuous temperature readings of oil and water.
After these tests it was a simple matter for the Ford engineers to return to Detroit with their recorded information, add to it low-speed running and time for pit-stops and acceleration and to them simulate automatically a full and complete Indianapolis race run at 150 m.p.h. average laps, or for that matter at any chosen speed or condition. This was the scientific approach to the engineering exercise of motor racing that makes sense, and Chapman could return to England to supervise the completion of 29/2 and 29/3, knowing that he need not worry about the reliability or performance of the V8 Ford engines.
The two new cars were completed in record time and on these the suspension units were of unequal lengths right and left, so that the body of the car was set to the left of the centre-line of the track by 2.38 in., in order to assist weight transfer under continuous cornering to the left. The stub exhausts were replaced by a multiple pipe system ending in two long tapering megaphones, as on the Coventry-Climax V8 engine and knock-off hubs and wheels were fitted. Firestones supplied special 15 in. tyres. Girling disc-brakes were used, rubber fuel tanks in each side of the chassis and a scuttle tank totalled 50 gallons of petrol and the dry weight was about 1,150 lb.
All three cars then went to Indianapolis for the start of official practice for the qualifying trials before the race, Gurney’s car being painted white with a blue stripe and Clark’s car green. After practising Gurney and Clark flew to England for the Silverstone meeting on May 11th and then flew back again to take part in the official qualifying weekend on May 18th/19th. Conditions were not ideal for a strong wind was blowing but nevertheless Clark set an average of 149.750 m.p.h. for the regulation four laps, but Gurney overdid things and spun into the retaining wall and wrecked his car. He was unhurt, and some feverish work by the Team Lotus mechanics got him out again in the prototype car, hurriedly built with some parts of the wrecked one. Gurney qualified at 149.019 m.p.h. so that unless there was a sudden improvement by all the remaining competitors both Lotus-Fords were sure of a place in the fastest 33 cars.
Fastest of all was Rufus Parnell Jones with a conventional Offenhauser-Meyer Drake engined car on an A. J. Watson chassis, with a speed of 151.153 m.p.h. and second was Jim Hurtubise with a supercharged 2.8-litre V8 Novi Special with 150.257 m.p.h. Clark was fifth fastest. The two Lotus drivers flew back to Europe to take part in the Monaco G.P. and then flew back to prepare for the race on May 30th, which is America’s annual Memorial Day for all their past wars, won or lost, and on which day the Indianapolis 500-mile race always takes place.
The race itself went almost according to plan, at one point the two Lotus-Fords were running first and second and near the end of the race Clark lay second and Gurney fourth, but an unforeseen pit-stop dropped Gurney to seventh place. Clark finished in second place, on the same lap as the leader after 200 laps, and only 34 sec. behind and ran the 500 miles with one stop for fuel and tyres, whereas Gurney had to change a second tyre near the end of the race and a bungle by the pit staff caused him to stop again to have a hub-nut retightened otherwise Lotus would have been second and fourth.
The whole project was an unqualified success and one that may well change the whole aspect of Indianapolis cars, just as the victories by the Grand Prix Maserati in 1939 and 1940 precipitated the long, low, sleek “Roadster” layout begun by Frank Curtis and continued by A. J. Watson which has reigned supreme at Indianapolis for 12 years or more. Lotus and Ford were out to win this year, and nearly achieved their objective, so we can rest assured that they will try again in 1964. No praise can be too high for Jim Clark, whose performance was all the more remarkable when it is realised that it was his first attempt at track-racing which is accepted as a specialised art, and his performance should answer all the remarks made by Floyd Clymer a year or two ago about Grand Prix drivers and their abilities.—D. S. J.