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Flow Rider: The Rise of Aerodynamics

Ford GT

2017 Ford GT

Ever since the introduction of the motor car, it has been an article of faith that cars will get more and more powerful, with the next mode l boasting more horsepower than its predecessor. Records must be broken; Top Trumps stats must be bettered. It’s the Jeremy Clarkson school of development – More! Bigger! Better! Faster! – and an arms race fuelled as much by marketeers as mechanics.

But any rational soul can see the problem here. Cars can’t go on getting more powerful for ever; it just doesn’t work like that. In 1990 a Ferrari 348 had 300 horsepower; now they are nudging 800, but no-one in their right mind would predict that in 30 years they will have nearly tripled again. Headline figures like 0-60 times and top speed have more or less plateaued. With the exception of those like Bugatti and Koenigsegg, who’ll continue to chase superlatives, we are reaching peak power for the supercar.

Not only is common sense against it, but the laws of physics have something to say about it, too. You can squeeze more horsepower than ever out of engines thanks to turbocharging, but it has to be controllable. The tyres, chassis, suspension and brakes all have to be able to cope – and not to mention the small matter of human reflexes.

2017 McLaren 720S

2017 McLaren 720S

Don’t just take our word for it. At the launch of the McLaren 720S last year, a couple of the engineers involved told Oracle Time that they genuinely didn’t know where it goes next; how to top this achievement in any meaningful sense.

The answer, both at McLaren and across the industry, is the rise of aerodynamics. Going fast in a straight line is one thing, but for real improvements in driving performance, carmakers are now looking to circuit records as the real benchmark. For example, the Nurburgring lap record has gone from being a fairly obscure prize chased by track day specials, to a bragging right lusted after by everyone from Honda and Chevrolet to Alfa Romeo.

Lamborghini Aventador SV

2017’s Lamborghini Aventador Superveloce Roadster can produce 170% more downforce than the standard Aventador.

As carmakers realised that scraping tenths of a second from acceleration figures was getting harder and harder, we started hearing more about downforce – kilogrammes and kilogrammes of it. The Lamborghini Aventador SV can produce 170% more downforce than the standard Aventador; a McLaren P1 can apparently produce 600kg of downforce; while even the rear wing on a Honda Civic Type R is good for 30kg pushing down on the back wheels.

Honda Civic Type R

2017 Honda Civic Type R

Talking of the Civic Type R, it’s impossible to ignore the fact that the quest for greater aerodynamic performance has had a tangible effect on car design. For a start the Civic’s roof is adorned with ‘vortex generators’, small nodules which are meant to marshall the air heading towards the rear wing for maximum efficiency. There are also aggressive vents before and after the front wheels to minimise turbulent air flow, and a huge rear diffuser – one of the real hallmarks of a modern fast car. The theory states that by diffusing airflow out behind the car, you speed up its flow beneath the car, creating low pressure that sticks it to the road.

McLaren Senna

2018 McLaren Senna

Another machine that has had its looks criticised for their slavish adherence to aerodynamic aids is the McLaren Senna. The latest vehicle in the Ultimate Series, it has been created as the last word (for now, anyway) in track performance. McLaren says that “From the front splitter to the double diffuser at the rear, you cannot follow a single line from the front to the rear without it passing through a functional air intake or vent.” Others say that it looks like what happens when you let the engineers design a car – but you cannot argue with the results; it will lap faster than a P1 despite having less horsepower (789 vs 903).

McLaren Senna GTR Concept

McLaren Senna GTR Concept

Perhaps the current supercar that balances aerodynamic supremacy with classical beauty is the Ford GT. In silhouette, you can see the bloodline that links it to the original 1969 Le Mans racer. But from any other angle, it’s clear that cutting through the air and generating grip were the guiding principles – from the huge scoops in the bonnet to the beautiful flying buttresses that funnel air over the rear spoiler. Nick Terzes, from the engineering team behind the GT, confirms this: “One of the great things about this car is that however beautiful and dynamic the design is, every single opening has a purpose on it. So if you see a large grille, if you see a scoop, it wasn’t just put there to look good, it was put there because it has a function.”

Ford GT

2017 Ford GT

Unseen are movable flaps in the nose that work in perfect harmony with the angle of the automatically adjusting rear wing, ensuring that front and rear downforce are always balanced. Air is taken in to cool the engine as you might expect, over the rear wheels, but what’s clever is Ford housed the outlets in the middle of the rear lights, removing the need for any extra vents that might spoil the overall airflow. Ford even chose the engine it would use as a result of aerodynamic concerns: “We started with aerodynamic efficiency – the efficiency of racing goes right down to the very core of its existence,” explains Jamal Hameedi, Ford Performance’s chief engineer. “The aero came first, then we picked the most efficient EcoBoost engine we could find for that package.” Truly, the age of brute force is over: this is the age of aerodynamics.

WHAT IS DOWN FORCE AND HOW DOES IT WORK?

As the name suggests, downforce has the effect of acting like a weight pressing down on your car, sticking it more firmly to the tarmac and giving it better grip. In simple terms, the principle is the opposite of the aerodynamic lift used by planes: car designers seek to create higher air pressure above the car, and lower below, through the use of wings, spoilers, diffusers and vents.

The challenging part of the process is that everything that adds downforce also generates drag, so a balance is required. Racecars adjust their setup for each circuit – too slippery and you risk generating lift that could send the car flying into the air; too much downforce and you won’t keep up with the pack. Supercar manufacturers, unconstrained by racing regulations, have adopted active aerodynamic components that seek the best of both worlds, coupled with software capable of modulating the airflow around a car for every different corner.

About the author

Chris Hall

Chris Hall is Deputy Editor of QP Magazine, based in London. He covers watches, motoring, technology and luxury travel, and has contributed to The Telegraph, the Financial Times, GQ and Wired.