Anybody else with an A5 (2012+) Beetle?

[freebeard]

Also wonder if fencing in the air going over the roof will be of any help in curbing turbulence?

In the only cases I know of, NASCAR and Bonneville, rooftop fences are used to induce turbulence. To kill lift if the car goes sideways.

[niky]

Originally Posted by freebeard

In the only cases I know of, NASCAR and Bonneville, rooftop fences are used to induce turbulence. To kill lift if the car goes sideways.

No, I mean, more like rails along the side to keep air from spilling over the side of the roof.

[kach22i]

Originally Posted by niky

No, I mean, more like rails along the side to keep air from spilling over the side of the roof.

The reason the air will want to spill over is that the air traveling over the top of the car travels a longer distance than that of the sides, and therefore will be of a different air pressure.

The higher pressure (slow air) at the sides will rise up to greet the lower pressure (fast air) and when doing so may create a vortex or funnel of rotating air.

The fences or rails at the edge of the roof line similar to a fender flare of a early 1970's McLaren race car will only delay the vortex formation, not eliminate it.

The delay might be useful in directing or locating the vortex to where you want it, perhaps you want it at another fin or wing for some reason - I don't know.

I wrote the above imagining a wind tunnel where the air is moving, because I have not yet come to terms with the air being still and the body moving through it. I'm pretty sure most people find the wind tunnel thinking favored over what ever the other method may be.

The #5 and #7 cars in the front are the Mclarens with fender fences.

Random TRANSPORTATION pictures - Page 1740 - Pelican Parts Technical BBS


More from that page:




I suspect that you don't see this done very often because delaying the vortex does not always lessen drag.

[freebeard]

http://blog.caranddriver.com/lemons-detroit-day-1-speedycop-civic-metsho-tempo-dmc-12-leading-classes/

I lied mis-spoke. I'd previously posted this example.

[kach22i]

The white Opel GT wagon in that link is awesome.

First image, car on the left.

[ECO-AKJ]

[QUOTE=freebeard;544461]
http://blog.caranddriver.com/lemons-detroit-day-1-speedycop-civic-metsho-tempo-dmc-12-leading-classes/

Don't they know they can go faster if they get rid of the wind drag and roll the windows up??

[niky]

[QUOTE=ECO-AKJ;544485]

Originally Posted by freebeard

http://blog.caranddriver.com/lemons-detroit-day-1-speedycop-civic-metsho-tempo-dmc-12-leading-classes/

Don't they know they can go faster if they get rid of the wind drag and roll the windows up??

LeMons cars are 10% function and 90% looking like total garbage to fool the scrutineers into giving them a pass.