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The Quora Column

Active aerodynamics, a slippery obsession

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Forget nearly everything you may know about aerodynamics. Images of wind tunnels whisking streams of air over and under the family sedan, this is not.

Active aerodynamics employs self-adjusting front and rear spoilers, open and shut vents, and in-motion height adjustments to keep vehicles firmly planted on the road while maintaining optimum efficiency – whether in terms of speed, downforce or fuel consumption.

Much of the technology was born (or banned, in the case of Formula 1) on racetracks, and now can be found on everything from the most coveted supercars to the simplest  four-wheeled conveyances.

To find out what drivers think about the emergence of “active aero”, as it is known, the members of the question and answer community Quora.com were consulted for a few active-aero musings.

Hiding in plain sight

Quora user David Chan named the 2014 Porsche 911 Turbo as a prime example of active aerodynamics. He noted the car has "an angle-adjustable rear wing that elevates at speed and also a three-piece front chin spoiler that drops down in two phases."

Indeed, at 75mph the 911 Turbo's front fascia wing extends down slightly and rear wing lifts for maximum control with minimal drag. The driver decides the next level of active aerodynamics with the press of a button in the cabin. The front and rear wings are then fully extended, creating maximum downforce. Fuel efficiency and a bit of speed are sacrificed here in exchange for heightened control.

As impressive as Porsche's active system is, Chan thinks the 1,001 horsepower Bugatti Veyron, which will end production shortly after a nine-year run, takes active aero to a new level. "Sure, it has the activated wing at speed, but the whole car exerts downforce and will actually lower itself for two height settings with a checklist to adjust height and retract vents to permit the car to achieve top speed," Chan said.

When the requisite 137mph is reached, the Veyron digs into the road by lowering itself by nearly two inches in the front and more than one inch out back. A rear spoiler extends as well, and flaps emerge near the front tires. For speeds beyond 233mph – yes, beyond – the driver can pre-set the ground clearance to less than three inches, close the front flaps and keep the rear spoiler flush with the car. The Veyron maintains this mode until the brakes are inevitably tapped and then extends the rear spoiler, all to keep driver on the road and out of the hospital.

Maximum control

Possibly no other car matches the sheer sophistication of the active aerodynamics found on the Pagani Huayra. Quora user Luke Pan noted the car "hides a series of sophisticated flaps that act like ailerons on an airplane, situated near the four corners of the car and integrated with the various trademark Pagani vents."

Pagani, which is based in Ferrari’s backyard of Modena, Italy, uses four flaps that pop up and down automatically based on aerodynamic calculations, which pair with the car's active front suspension to balance drag and downforce:

The flaps "work frantically when the car is at its best,” Pan writes, “adjusting instantly as its central brain sorts out the most effective angles [for] steering, throttle, and braking input, body pitch, yaw and roll, and several other factors.

"Watching the flaps work is quite an unusual sight,” he concedes, “but the end result is staggering, given its cornering speeds."

Active aero for the everyman

While these supercars need active aerodynamics to achieve the highest possible performance and control, the technology has also found its way into some of the most common vehicles on the road.

Quora user Shams Kazi mentioned early turbo versions of the Volkswagen New Beetle used active aerodynamics to raise and lower the rear wing. This built on earlier efforts with its 1990s-era Corrado sports hatchback. VW has since scrapped the Beetle's active aero, but other mass-production cars are bundled with their own systems.

The Eco model of the Chevrolet Cruze, for example, can be had with active front grille shutters that automatically close when the engine does not require gobs of air for cooling, which enhances fuel efficiency. Corporate parent General Motors now uses the technology across its brands.  

As active aero trickles down even to economy cars like the Cruze, a debt should be paid to the Le Mans endurance-racing circuit, a veritable test bed of aero tech. More auto-adjusting air dams, self-activating wings and other air-bending goodies will soon sprout up in passenger vehicles as a direct inheritance from these hyper-advanced machines. As goes racing, so goes the grocery-getter.

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