|McLaren M28 Cosworth|
With the 'M28' introduced at the start of the 1979 season, McLaren were among the very last of the top teams in Formula 1 to embrace 'ground effect' aerodynamics. Pioneered by Lotus in 1977, the innovative design was used by their driver Mario Andretti to win the World Championship a year later. In stark contrast, McLaren slipped from third to seventh in the constructor's standings.
Very efficient, ground effect aerodynamics relies on the air-flow under the car to generate downforce with little to no drag penalty. More specifically, the air fed through the wing-shaped tunnels running on either side of the cockpit under the 'side-pods'. For his first ground effect car, McLaren designer Gordon Coppuck fully explored the regulations to create the largest tunnels permitted.
To allow for the very wide side-pods, Coppuck penned a particularly narrow monocoque chassis. This featured a novel honeycomb construction with a Nomex core sandwiched between two sheets of aluminium. Although heavier than the conventional single-sheet aluminium monocoques previously used, the new chassis was substantially stronger and better suited to cope with the increased aero forces.
The diminutive chassis was hidden from sight by the vast side-pods that completely filled the area between the front and rear suspension. The underside was shaped like the top surface of an airplane wing, which effectively sucked the car to the ground. The vast space inside the side pods was also used to house the car's radiators and a fuel tank each, while a third tank was fitted behind the driver.
Like most F1 teams of the day, McLaren relied on the readily available Ford Cosworth DFV engine, which was used as a fully stressed member of the chassis. The suspension was conventional although adapted to make the airflow of the ground effect tunnels as clean as possible. The rear end, for example, featured in-board brakes and springs mounted vertically on either side of the six-speed gearbox.
The first ground effect McLaren was ready late in 1978, which allowed the team to submit the M28 to extensive tests before it made its competition debut in Argentina. Some minor issues surfaced with subtle modifications required to optimise the unusual suspension geometry, while the honeycomb monocoque also raised some problems. Signed to drive for the team this year were John Watson and Patrick Tambay.
Watson gave the M28 a promising debut with a third place finish in the Argentinian Grand Prix after starting from sixth. Sadly this result proved an exception than the rule. Despite continuous updates, both Watson and Tambay struggled to get decent results with the M28. Halfway through the season, at the all-important British Grand Prix, McLaren fielded the all-new M29, which featured a more conventional single-sheet monocoque.
In the end the M28 served McLaren for just half a season. Due to his focus on optimising the design for ground effect aerodynamics, Coppuck compromised the rest of the car. As a result, it was too big and heavy to ever be competitive. All three of the cars built still survive and one was recently restored to full running order for historic racing.
Article by Wouter Melissen, last updated on July 20, 2012
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