How to design a McLaren P1

You may think that car design involves pens and paper. But when you're designing a McLaren P1, that isn't always the case. "See the little shapes behind the front wheel?" says Frank Stephenson, the company's design chief. "We didn't draw those - they came out of a computer. We just refined them and made them look sexier."

When Frank's brief came down from Ron Dennis, it looked like this: build the successor to the legendary McLaren F1. A hypercar capable of defeating LaFerrari. Make it produce 600kg of downforce at 161mph. Find room for a KERS module. "When the brief came, you start going crazy," he says. "You think, ‘how do we better a car that's already iconic?' Of course we have new technology and innovation but people were saying, ‘you can't repeat an icon'. But I don't think any of us had any worries or fear of creating it. Because as a designer you're geared to think you can do something better than anybody else has done before."

Words: Rowan Horncastle

Photos: McLaren

Stephenson's CV backs up the bravado. He's been involved - at various levels - in some pretty big projects: the New Mini, Maserati Gran Sport, Maserati MC12, Ferrari 430, Ferrari FXX, Fiat 500 and Alfa Romeo Mito. He also had a hand in that massive ‘whale tail' on the back of an Escort RS Cosworth. This must deserve a beer or two.

Working at McLaren is a bit different. "Some people try to make things look beautiful to create emotion, but we don't make beauty the overriding element," he says. "It's up there, but the overriding element is to make the car perform. It's like when people design anything that doesn't have to be sold but has to go fast - military aircraft for example. Nobody sits down and tries to make an F-22 Raptor look beautiful, they just design it to perform and it looks stunning."

He talks about the P1's ‘negative surfaces'. Have a look at side of the car - they took the side panel out, because you don't need it. Frank reckons that taking stuff away actually adds character to the car, and creates the feel of an exoskeleton. But simply ripping panels off doesn't make one of the best cars in the world. The P1 is going up against Ferrari's LaFerrari. And like its great rivals Ferrari, McLaren has had to push the boundaries of how a car reacts to the air around it.

"The P1 isn't concerned with aerodynamics as you'd think it is," says Frank. "It's more about downforce. When you have an engine like the P1's you don't care about aerodynamics because you know the car has enough power to be fast. The whole issue at the beginning of P1 was to generate 600kg of downforce. So it was a case of turning aerodynamics on its head."

The secret of the P1's downforce, then, is the diffuser. Or more specifically, how much space Frank and his team could create between the floor and the top of it. The more you can make the air expand as it comes out the back, the more it'll suck the car down. Which he why he used a double diffuser, the sort that caused trouble in F1 a few years back.

Those of you with eyes may've seen a difference between the P1 unveiled in Paris and the final production version shown more recently at Geneva. On the Paris car, the rear honeycomb effect - where the taillights normally sit - was filled in, but on the production car it was hollow. "The rear of the car is designed to get all the heat out," Stephenson says. "We want to get the maximum heat out of the car so we thought, ‘lets get rid of the taillights as they take up a big area'. But that forced us to make a very thin strip of lights along the trailing edge."

The heat blasting out of the back generates a bit of a headache. "The innovation started not by taking air in from the side of the car, but to ram it into the car" says Frank. "So what we did was put the main intakes on the shoulders of the car. Nobody's ever done that. But the problem of taking it from the shoulders is that you have to get cold, clean air into the intakes, and into a snorkel for the turbos." His solution was to find a way to split the air so it went between the snorkel and shoulders of the car, avoiding the hot air coming out of the radiator at the front.

So where do you go next, when you've got the 12C and P1 under your belt? "We're starting to get a design language," says Frank. "But the company's too young to say this is how McLarens are always going to look. You want to go against what's predictable; you want customers to go, ‘oh wow!' That's not what Audi are doing. There shouldn't be a lot of excess material on the car, it has to be tight. Zero body fat."

Stephenson is currently working on McLaren's Porsche 911 rival - yes, they're doing one - code-named ‘P13'. And if you're expecting a baby P1, you may be wrong. "P13 is going to be different to 12C and P1, but in a much fresher way," says Frank. All the cars have to hang together as they're going to sit in the same dealership, so you don't want one to look like it's got an odd father. I can say that the quarter window will relate to all the cars and is very ‘F1-ish' [that's the F1 road car, not race cars]. Also the line down the side of the P1 is from the F1."

Only 375 P1s are being built, each costing £866,000. Production starts later this year. But it's got one hell of a rival in the new LaFerrari. So what does Stephenson - a former Fiat Group employee - think of Maranello's masterpiece? "I think the car is about trying - trying - to look dramatic," he says, "it doesn't come across to me as being one hundred per cent efficient in the design. It's new, it's got the wow factor and is definitely more attractive than the Enzo ever was. "The Enzo didn't come across to me as Italian. This one does look Italian but it looks like those girls who are dressed to kill at 9am. But it does look lot more sensual than other cars. It's a lot like a pretty girl... but she's got a lot of scars on her."