The McLaren MP4-12C is intended to be the first in a range of high-performance sports cars from McLaren Automotive, the independent car division based at the McLaren Technology Centre in Woking, UK. The MP4-12C is a two-seat mid-engine model in the ‘core’ sports car market segment for cars costing £125 000-175 000. The heart of the new car is the Carbon MonoCell. McLaren pioneered carbon composite construction in the 1981 Formula 1 MP4/1 race car. It brought carbon fibre technology to road cars with the 1993 McLaren F1 supercar and then built on this experience with a carbon fibre chassis and body on the Mercedes-Benz SLR McLaren (2003-2009).
The 12C MonoCell weighs less than 80 kg. Its torsional rigidity is considerably stiffer than a comparable alloy structure. This inherent lack of flex means the front suspension system, which is mounted directly onto the MonoCell, requires less compromise for flex of the suspension itself. The MonoCell also acts as a safety survival cell, as it does in a Formula 1 car.
In the event of an accident, the light weight aluminium alloy front and rear structures are designed to absorb impact forces in a crash and can be replaced relatively easily. Aluminium extrusions and castings are jig welded into the finished assembly and bolted directly to the MonoCell. Cars with full aluminium chassis use their structure to absorb and crumple on impact, which implies more fundamental damage to the whole structure, including the passenger cell, in a major accident.
McLaren reports that it has developed a new carbon fibre production process that allows the hollow MonoCell to be produced to exacting quality standards, in a single piece, in only four hours. Typically, dozens of carbon components (and dozens of production hours) feature in a carbon fibre chassis structure.
The Carbon MonoCell not only reduces the weight of the structure but also allows for the use of much lighter weight body panels.
“We have spent most of the programme ‘adding lightness’,” says Mark Vinnels, McLaren Automotive Programme Director. “If the cost of reducing weight brought performance gains in speed, handling or economy, we did it. However, if the expense could deliver improved performance elsewhere we didn’t pursue it. We never set weight targets as such; we set cost-to-performance targets and examined everything in this way." “A good example of this philosophy is that we considered carbon fibre body panels," he adds. "They would have reduced weight but added little benefit as the new one-piece Carbon MonoCell provides all of the torsional strength the body needs. The costs saved were used elsewhere for greater weight reduction and efficiencies overall. This was the holistic approach to weight saving that we used all the way through development."
“The whole 12C project is based on the concept of the MonoCell," explains Claudio Santoni, McLaren Automotive Body Structures Function Manager. "This means that McLaren can launch into the market with greater performance than our rivals and a safer structure. To put it into perspective, if the costs and complexity of producing a McLaren F1 carbon fibre chassis are taken as a factor of 100, the 12C chassis production costs are reduced to a factor of seven or eight, without degrading the strength or quality of the carbon fibre structure. And this step-change in technology could make its way into more mainstream cars.”
The 12C is powered by a bespoke McLaren ‘M838T’ 3.8 litre, V8 twin-turbo engine producing around 600 bhp, driving through a McLaren seven speed Seamless Shift dual clutch gearbox (SSG).