“We designed every component from scratch to meet the extreme goals of the 12C and avoid any compromise,” said McLaren Automotive Managing Director Antony Sheriff of the company’s newly revealed, advanced technology MP4-12C sports car. That technology includes a one-piece carbon-fiber chassis structure called the Carbon MonoCell, which took five years to develop and is claimed as a “first,” bringing both dynamic benefits and fundamental engineering opportunities.
"When we embarked on the 12C project, we wanted to rewrite the rules of sports car design,” added Sheriff. McLaren is aiming to produce a car that sets new power, performance, economy, and emissions standards in its sector.
Slated for sale in 2011, the new model, first in a planned range of high-performance sports cars, has a two-seat, mid-engine configuration and a U.K. market position between £125,000 and £175,000. It uses no carry-over parts from any other car—not even switches—and will be built in Britain.
The power unit of the rear-wheel-drive MP4-12C is described as a “bespoke” McLaren M838T 3.8-L V8 twin turbo. Output is “around” 450 kW (603 hp) and maximum torque about 600 N·m (443 lb·ft). Its rev limit is 8500 rpm, and around 80% of its torque is available below 2000 rpm with the help of dual variable valve timing. The engine has a flat-plane crankshaft, dry-sump lubrication, and composite cam covers and intake manifolds. The car's transmission is a seven-speed McLaren Seamless Shift dual-clutch unit.
“There are so many examples of racecar process and technology transfer in the 12C,” said McLaren Automotive Technical Director Dick Glover. “Brake Steer was pioneered on our F1 car in 1997; it helps to dial out understeer on entry to a corner and improve traction on the way out. Another is a Pre-Cog function on the gearshift rocker that effectively primes the gearbox for the next change.”
But it is subtle, determined, holistic weight saving—even a few grams—that probably leads the panoply of technology that makes up the 12C. The aim was not to set specific weight targets but rather to set cost-to-performance targets, examining everything in the process.
Particularly significant was the car’s MonoCell, not only reducing the structure’s weight but also facilitating the use of lighter body panels. It has a mass of 80 kg (176 lb) and forms the structural basis of the whole car. The tub’s torsional rigidity is “considerably stiffer” than that of a comparable alloy structure, says McLaren, which has pioneered a new carbon-fiber production process. The MonoCell can be produced as a single piece in 4 h.
McLaren also came up with an interesting cost figure. If the cost and complexity of producing a McLaren F1 carbon-fiber chassis represent a factor of 100, the 12C’s chassis production costs are about a factor of seven or eight, without any degradation of strength or quality. All fins, vents, and the car’s flat underbody are said to be part of the reason, with no styling addenda just for eye appeal. The company also cites the close position of driver and passenger as allowing a narrower, lighter body.
Other weight-saving features are standard brakes that weigh less than optional larger carbon ceramic types. McLaren has developed a composite braking system using a forged aluminum bell that attaches to the cast iron disc, saving 8 kg (18 lb). Lightweight exhaust pipes that exit from the rear of the car have shorter length than similar designs. Airflow-assisted airbrake deployment cuts the weight of its activation system. The compact engines helps minimize vehicle length, weight, and polar moment of inertia. The car’s alloy wheels were subjected to FEA (finite-element analysis) to pare weight. And engine radiators are positioned as close to the engine as feasible, minimizing pipework and the fluids they carry, again saving weight.
Carbon fiber body panels were, however, rejected as a solution, and the money saved in other elements of the design for greater weight reduction and efficiencies overall.
A combination of styling that Design Director Frank Stephenson hopes will prove “timeless,” and aerodynamics that provide impressive downforce, determined the car's aesthetics. Airflow control generally is also a key part of the car’s design. Positioning the radiators adjacent to the engine may reduce weight and the car’s width but presents potential airflow challenges. So side air scoops and integrated turning vanes are part of the car’s styling for purely functional reasons.
The 12C's suspension comprises double wishbones with coil springs, adaptive dampers, and Proactive Chassis Control, which replaces mechanical antiroll bars. Brake Steer, a development of an electronic system used on McLaren’s 1997 MP4/12 F1 car, applies the inside rear brake if the car enters a corner too quickly to achieve the ideal radius, increasing yaw rate and reducing or preventing understeer.
The 12C follows the McLaren F1 (1993-98) and the Mercedes-Benz SLR McLaren (2003-2009). Prototype build has proven the robustness of McLaren’s production system and quality levels and led to significant reduction in station cycle times, said the company.