|McLaren M16E Offenhauser|
British manufacturer McLaren made their debut at Indy in 1970 with the Offenhauser engined M15. Designed by Gordon Coppuck, this was a relatively conventional car, borrowing heavily on the dominant M8 series of Can-Am racers. Although not an instant winner, the M15 proved competitive enough for McLaren to have another go the following year.
Using the lessons learned and drawing inspiration from Lotus' revolutionary wedge-shaped 72, Coppuck created the all new M16. He was not yet convinced of the use of the wedge shape for the team's Formula 1 cars but felt this low-drag design would perfectly suit high-speed oval racing. As a consequence of the sharp nose, the radiators had to be moved from the front of the car to 'side-pods' on either side of the cockpit.
The chassis itself was a straightforward aluminium monocoque, which used the familiar, turbocharged Offenhauser as a semi-stressed member. Two A-frames mounted on either side of the engine bore the rest of the load. At the front the springs and dampers were mounted in-board, out of the airflow to the radiators. The rear suspension was fitted to the Hewland gearbox and consisted of top links, reversed lower wishbones and twin-trailing arms.
The real ace up Coppuck's sleeve was the engine cover with integrated wing. Being part of the bodywork, this was a very clever way around the USAC's (the sports' governing body) ban on wings. The rear wing was deemed necessary to balance out the downforce generated by the flat nose. The nose itself also featured two smaller wings on either side for trimming purposes.
During a 'social' visit to the McLaren factory late in 1970, Roger Penske and his driver Mark Donohue were shown the new Indy racer. They had come to England with the idea of doing a deal with Lola but they were immediately taken by the spectacular wedge-shaped machine. Penske bought two cars and both parties agreed to share their resources and knowledge during the development.
At Indy, Donohue was joined by works drivers Peter Revson and Denny Hulme. The Sunoco liveried Penske car dominated most sessions but it was Revson who clinched pole. Donohue immediately grabbed the lead and ran away from the field until his gearbox broke. Revson faded away and Hulme retired, handing the win to Unser in an Eagle. Later in the year, Donohue did take two USAC wins with the M16.
Even before the year was out, many of the existing teams had caught up. This had not gone by unnoticed in the McLaren factory and a revised M16B was readied. It featured a shorter nose-cone, which allowed for the rear wing to be mounted further back while still complying with the maximum length. Still very much committed to the M16, Penske bought two new examples for a full USAC season.
Eclipsing the McLarens for outright speed in 1972 was the new Eagle driven by Bobby Unser. Accordingly, he clinched pole at Indy ahead of Revson and Donohue at record pace. Gambling on the retirement of many of the rivals, Penske sent Donohue out with the boost turned down. This strategy paid off handsomely when Donohue inherited the lead with just over a dozen laps to go. Like Lotus almost a decade earlier, it had taken McLaren three attempts to beat the established manufacturers.
Encouraged by Donohue's success, McLaren reworked the M16 once more. Such was the confidence in the basic design that a Formula 1 version was also constructed, which would ultimately win two world titles. The new M16Cs featured a proper engine cowling, revised side-pods and a rounder cockpit surround, which was similar to the one fitted on the M23 Grand Prix car.
In the works squad, Revson was joined by new signing Johnny Rutherford. He immediately qualified the latest M16 on pole for the Indy 500. In the race he was thrown back due to reliability issues and eventually finished ninth. Placing fifth, Gary Bettenhausen's Penske entered M16C was the highest placed McLaren. In the remainder of the season, Rutherford won two races and Bettenhausen one.
No new cars were built for 1974 but instead the existing M16s were updated to M16C/D spec with an even smoother cockpit surround, shorter nose and larger rear wing. Despite qualifying in a lowly 25th due to problems, Rutherford clinched his first victory at the 'Brickyard'. David Hobbs was fifth in the other works car. Rutherford would go on to take three more USAC victories in the M16C/D that year.
McLaren deemed that there was life left in the M16 and had a young John Barnard prepare yet another evolution. 'His' M16E featured a longer wheelbase and revised rear suspension. Seasoned USAC racer Lloyd Ruby joined Rutherford as a works entry. The race was called early due to heavy rain. At that time Bobby Unser was leading in his Eagle and Rutherford was second. Ruby was already out of the race on lap seven with a burnt piston.
The M16E was brought again in 1976 for Rutherford and he managed to clinch pole ahead of an earlier Penske entered M16 driven by Tom Sneva. Mario Andretti had actually set the fastest time in another Penske M16 but at the wrong time and he had to settle for 18th on the grid. Rutherford in the mean time continued the M16's even streak by scoring the type's third Indy 500 victory, six years after its spectacular debut.
After six seasons and five evolutions, McLaren finally had to develop a new car. This was mainly due to the quick rise to the top of the Cosworth DFX V8 engine. Dubbed the M24, the new McLaren Indy racer was clearly a development of the M23 F1 car, which in turn was closely related to the M16. The M24 was also immediately competitive, scoring several victories but not at Indy.
With three victories in six years, the McLaren M16 ranks as one of the all time great Indy racers. It dominated in one of the sport's most competitive eras and was driven by some of the all-time great racers. Unfortunately McLaren was not able to repeat the same success with the later M24s and the British squad left USAC racing to focus solely on F1 in 1980. M16s were run at Indy by privateers as late as the early 1980s.
Article by Wouter Melissen, last updated on March 18, 2011
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