There were 84 entries seeking one of the 33 starting berths in the 54th annual Indianapolis 500, but despite a great variety of chassis and an array of new equipment, this American classic once again proved that a team which isn’t ready when practice opens on May 1st stands little chance of being first to the chequered flag on May 30th. There were 25 different makes of car entered this year but there was far more unanimity when it came to the choice of powerplant – all but 12 of the 84 entries having 2.65-litre turbocharged versions of either the venerable Offenhauser or the more recently developed Ford. The turbocharged Offenhauser was first introduced at Indianapolis in 1966 and powered the winning car for the first time in 1968. The same year Ford brought out a turbocharged version of their normally aspirated 4.2-litre d.o.h.c. engine and this powered the winning car for the first time in 1969. It was hardly surprising, then, that this year, for the first time, all 33 cars that made the race used turbocharged engines – 18 of them Offenhausers and 15 Fords.
Of all the cars entered, undoubtedly the best prepared were the two P.J. Colts for Al Unser and Leonard, Donohue’s Lola, the two McLarens for Hulme and Amon, and Foyt’s Coyotes. Close behind were Ruby’s Mongoose (one of the few spaceframe cars), Gurney’s Eagle, McCluskey’s Scorpion, Andretti’s McNamara and Brabham’s Brabham. Inevitably, however, these new cars were all plagued by teething troubles and it is significant that the cars which dominated practice and the race – the Colts, the Lola and the Coyotes – although also new, were essentially refined developments of established, proven designs. Parnelli Jones’ Colts, for example, were designed and built in California by his chief mechanic, George Bignotti, but are based almost entirely on the Lolas that Bignotti has run for the past two years. Donohue’s Lola, a T-153, is the fourth in Eric Broadley’s T-150 series of Indianapolis cars that began in 1968 and differs from last year’s T-I52 in having slightly larger fuel capacity (the Ford used this year is more thirsty than the Offenhauser used last year) and revised suspension pickup points and geometry. Foyt’s Coyotes are also refilled versions of his 1969 cars, and like the Lola and the Colts he used Fords for power.
The McLarens were the most interesting from the technical point of view and reflected the team’s usual completely integrated design approach. In many ways single-seat versions of their Can-Am cars, the monocoque of the M15 ends behind the cockpit, with the Offenhauser engine (helped by bracing struts) acting as a stressed member and the rear suspension attached to a bridge over the transmission. Most interesting of the car’s technical features are cylindrical hydraulic jacks on top of the front springs that can be actuated by the driver while in motion to compensate for reduced fuel loads or changing track conditions, and an interconnection between the single upper links of the rear suspension to reduce camber change on the left rear wheel (always lightly loaded in Indianapolis’ four left turns). Unfortunately for the McLaren team, Hulme’s practice ended when he received severe burns to the backs of his hands after a fuel cap came loose and the car caught fire. Shortly afterwards Amon decided he could not adjust to the idiosyncrasies of Indianapolis and returned to England, leaving Williams to take over his car and Revson to take over Hulme’s.
Gurney’s new Eagle, a Len Terry design with an Ofienhauser for power instead of Gurney’s favourite stock block Fords, was bothered by both handling and engine gremlins; Andretti’s first McNamara crashed when a rear wheel bearing seized; Ruby was burning holes in pistons at an astonishing rate, and Brabham’s new BT32 wasn’t running until after the first weekend of qualifying.
Hulme set the pace during the first six days of May, with a high speed of 167.9 m.p.h., but then Al Unser took over, thoroughly dominated practice for the remainder of the month, and established himself as the leading contender for the pole position and the race. While many of the leading drivers were struggling to reach 169 m.p.h., or even 168 m.p.h., Unser hit 170.973 m.p.h. by the 10th of the month, raised that to 171.233 m.p.h. the next day, and went on to win the pole position with a four-lap, 10-mile average of 170.221 m.p.h. Three-time winner A. J. Foyt, the only other driver over 170 m.p.h. during the first two weeks, surprised no one by putting his Coyote on the front row with an average of 170.004 m.p.h., but then Johnny Rutherford, a good but not outstanding driver, did surprise everyone except himself and his crew when his four-year-old Offenhauser-powered Eagle came within 1/100th of a second (2 1/2 feet) of knocking Unser off the pole position with an average of 170.213 m.p.h. Only one other driver (McCluskey) qualified at over 169 m.p.h. and several drivers, including Ruby and Brabham, had to start from well back in the pack as a result of not qualifying the first weekend.
Unser, however, was the class man of the field, as he showed clearly by taking the lead on the first lap and then, breaking records almost all the way, led all but 10 laps of the 200-lap, 500-mile race to score the most overwhelming victory since Jimmy Clark won the 1965 race. Only an accident in the final to laps, which slowed the field to a snail’s pace, prevented Unser from breaking Andretti’s 1969 race record by over 4 m.p.h. Bignotti’s efficient crew executed his three compulsory fuel stops in a total of less than 64 seconds and Unser lost the lead only twice – for five taps each during his first and second fuel stops. By the third stop, however, he had lapped all but Foyt and Donohue and was so far in front that he was able to make his stop and rejoin the race without losing the lead.
Foyt, who took over second from Rutherford when the latter’s clutch jammed during the first pit stop, held that position for most of the race but was never able to challenge Unser seriously and after losing top gear with just 15 laps to go he fell to 10th at the finish. Despite being plagued by severe understeer throughout the race, Donohue had a solid grip on third place for more than half the race and after Foyt’s trouble moved up one spot to finish a deserving but disappointed second, 32.19 seconds behind Unser. Unser had actually lapped the entire field 15 laps from the finish but then eased off and allowed Donohue to unlap himself. The next three drivers – Gurney in his Eagle, Donnie Allison in an Eagle entered by Foyt and Jim McElreath in a Coyote entered by Foyt—also completed the full 200 laps because at Indianapolis the race continues for five minutes after the winner receives the chequered flag. Mario Andretti, who had to wrestle his McNamara for 450 miles as a result of a binding halfshaft (it suddenly freed itself when the car hit a bump), had to settle for sixth place, one lap behind the leaders. Williams was the only McLaren driver to finish (in ninth place with 197 laps), Revson having retired after 87 laps with a sick engine. Brabham, who ran in the top six for much of the race despite severe oversteer, retired with only 25 laps to go with a seized engine.—D. G.