McLaren Reveals the Secrets of Staying Dry with no WindshieldMcLaren Reveals the Secrets of Staying Dry with no Windshield

How McLaren Automotive's Elva sports car's Active Air Management System steers air around the cockpit

Dan Carney, Senior Editor

April 14, 2020

3 Min Read
McLaren Reveals the Secrets of Staying Dry with no Windshield

 

The most striking feature of McLaren’s new Elva sports car is the complete absence of any kind of a top, even including the windshield. The design makes for wonderful theater, but how in the world does this actually work for drivers who don’t want to wear a full-face racing helmet for protection from the wind blast at speed?

We’ve all put our hands out the window of moving cars. Imagine the force of that wind hitting you in the face! Rather than diverting that airflow with glass, McLaren engineers are employing a wall of air to shove the airflow up and over the Elva’s occupants. 

They call it the Active Air Management System, and if this sounds like a dubious proposition, McLaren has released a video outlining the system’s function.

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Image source: McLaren Automotive

“If you are sitting in the car with the system deployed at, say, 100 kilometers an hour or 120 kilometers an hour, you can sit here in relative calm,” explained Dan Parry-Williams, Director of Engineering Design, McLaren Automotive. “Your hair, if you have hair, is unruffled,” noted the decidedly balding engineer. 

The Elva’s purpose is to return modern sports cars, which have been criticized as being too antiseptic, back to their roots. “When we talk about pleasure and exhilaration, and exposure in this case, that meant stripping the car of absolutely everything, including windscreen. So effectively no weather protection at all. And that presented the aerodynamic challenge for this car.”

A challenge, indeed. One that can be realistically solved? That’s what McLaren’s team wondered, too. “With absolutely nothing between you and the wind coming at you, would it be possible to create a virtual canopy? And that was the challenge we set ourselves.”

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Parry-Williams demonstrates the exit angle of the Active Air Management System's air jet. Image source: McLaren Automotive

The solution is to re-route air flowing into the car’s grille and blast it at the air flowing over its hood toward the occupants. “Inside here, there’s a giant hook-shaped duct,” said Parry-Williams. “Air is channeled in the front of the car from the area with the highest pressure obviously, as the car is pushing its way through the air. This air is all ducted and channeled through the center of the car and is turned through 120 degrees and actually exits the top surface in this direction. So it is fired out of here at very, very high velocity. Of course, there’s onrushing air coming behind it. And that high-energy channel of air that is being forced up here is bent back by the oncoming air and is effectively curved back all the way over the canopy.”

Then he admits that, well, they also cheated a bit. A jet of air is great, but at speed, it needs some help. So the Elva has a ramp that slide upward just behind the exhaust vent for the air shield, providing some rigid support to the air stream and a firm obstacle to air headed toward the car’s occupants. “This actually rises at speed when you start going faster and faster,” said Parry-Williams.

The driver also has the option of getting the full blast of wind straight in the face, if they want to give that a try. “The whole system can be switched off from inside the car,” he said. “There is an internal flap that shuts the whole duct off.”

In that case, be sure to bring a helmet with a faceshield!

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Dan Carney is a Design News senior editor, covering automotive technology, engineering and design, especially emerging electric vehicle and autonomous technologies.

About the Author

Dan Carney

Senior Editor, Design News

Dan’s coverage of the auto industry over three decades has taken him to the racetracks, automotive engineering centers, vehicle simulators, wind tunnels, and crash-test labs of the world.

A member of the North American Car, Truck, and Utility of the Year jury, Dan also contributes car reviews to Popular Science magazine, serves on the International Engine of the Year jury, and has judged the collegiate Formula SAE competition.

Dan is a winner of the International Motor Press Association's Ken Purdy Award for automotive writing, as well as the National Motorsports Press Association's award for magazine writing and the Washington Automotive Press Association's Golden Quill award.

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He has held a Sports Car Club of America racing license since 1991, is an SCCA National race winner, two-time SCCA Runoffs competitor in Formula F, and an Old Dominion Region Driver of the Year award winner. Co-drove a Ford Focus 1.0-liter EcoBoost to 16 Federation Internationale de l’Automobile-accredited world speed records over distances from just under 1km to over 4,104km at the CERAM test circuit in Mortefontaine, France.

He was also a longtime contributor to the Society of Automotive Engineers' Automotive Engineering International magazine.

He specializes in analyzing technical developments, particularly in the areas of motorsports, efficiency, and safety.

He has been published in The New York Times, NBC News, Motor Trend, Popular Mechanics, The Washington Post, Hagerty, AutoTrader.com, Maxim, RaceCar Engineering, AutoWeek, Virginia Living, and others.

Dan has authored books on the Honda S2000 and Dodge Viper sports cars and contributed automotive content to the consumer finance book, Fight For Your Money.

He is a member and past president of the Washington Automotive Press Association and is a member of the Society of Automotive Engineers

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