When IndyCar requested manufacturers to design a brand new chassis for the 2012 season, British Ben Bowlby jumped at this opportunity to showcase his revolutionary ideas. The result of his labours was the highly unconventional 'DeltaWing' shown for the first time at the 2010 Chicago Auto Show. The arrow-shaped machine had a mixed reception with some critics doubting it could even go round a corner.
Although Bowlby's design was far from conventional, it did use many existing principles. The core of the idea was to achieve the same result with half the power and half the weight. To achieve this very green objective, Bowlby went to dramatic measures to reduce the drag by using a very narrow nose and no wings. Instead the necessary downforce was generated by ground-effect aerodynamics.
Eventually the IndyCar organisation went for the safest option and extended their deal with Dallara as the series' sole chassis supplier. Fortunately, this was far from the end of the pioneering project as the 24 Hours of Le Mans organisers ACO opened the 56th slot on the grid for green cars. With the help of some of American motor racing's greats like Dan Gurney's All American Racers, Highcroft Racing and Don Panoz an entry has been readied for the 2012 Le Mans.
All American Racers in California has been responsible for constructing the car at their California base. Much time and resources were saved by using an off-the-shelve carbon-fibre chassis, supplied by Aston Martin Racing. This had previously been used for the much troubled AMR-One, which had been axed after just a few months. Due to the unique nature of Bowlby's design only the tub could be used while bespoke parts were required for the rest of the car.
The focal point of the DeltaWing is no doubt the very narrow nose with the wheels mounted side-by-side. The suspension was bolted to an extension of the carbon-fibre monocoque and consists of very short, unequal length double wishbones with coil springs and dampers but no anti-roll bar. The skinny tyres have been purpose developed by Michelin for the car. Unusually, the front wheels feature three small studs instead of one big nut.
At the time of the original announcement, no engine supplier was named and it took until late in 2011 before Nissan stepped up and soon after the car was officially labelled the Nissan DeltaWing. Specifically for the DeltaWing, they had a competition version of their direct injection four-cylinder engine developed by RML in England. Displacing 1,600 cc, the turbocharged unit is officially rated at 300 bhp. This power is fed to the rear wheels through a five speed gearbox.
A key element of the DeltaWing design is the highly efficient aerodynamics. Using a very narrow nose with arrow-shaped side-pods, the car produces only very little drag. Rear-view cameras were initially specified but on the ACO's insistence, conventional mirrors have been fitted, reportedly increasing drag by 8%. The necessary downforce is generated by ground-effect tunnels fitted under each of the two side-pods. These create low pressure area under the car, effectively sucking it to the ground.
Another essential aspect of the design was to keep the weight down to a minimum. Lightweight materials were used throughout and even the engine only weighs 91 kg. As a result the complete DeltaWing without fuel and driver tips the scales at just 475 kg. The very low weight and drag figures allow the car to run at the same speeds as much bigger engined machinery, while at the same time using less fuel and tyres.
With the help of RML, the Nissan DeltaWing was prepared for and entered in the 24 Hours of Le Mans by Highcroft Racing. One of the 'Garage 56' conditions is that the car will not be classified, so the extensive development work focused mainly on ensuring the car was reliable. In the months building up to the race the car was tested on both sides of the Atlantic by assigned drivers Marino Franchitti, Michael Krumm and Satoshi Motoyama.
The official Le Mans Test early in June was the first public outing for the car and the early critics were quickly silenced; the DeltaWing could turn. One of the main objectives of the day was to gradually work towards the 3:45 lap time the ACO requested the team to stay above. Underlining its green credentials was the fact that all but one lap during the test was completed on the same set of tyres. A set of rain tyres was fitted for that one other lap.
While not in contention for the outright win, the striking DeltaWing will certainly be one of the stars of this year's 24 Hours of Le Mans.