Wheel wake

[Mpgian]

Originally Posted by XJguy

I can see that as being the case for a plane where the the concern is drag while in the air. But on a car the wheels rotate pumping air up and over into the wheel bay/well.

do you mean getting pumped up behind the wheel...

I just cant see too much air being pumped up from behind the wheel unless you had HUGE tire tread...

wouldent the air get squished out by the tire?

[XJguy]

It happens even with slicks. Maybe if you were to have bicycle width tires or even the very thin tires used at Bonneville, but anything else its quite significant.

[aerohead]

Originally Posted by XJguy

I am a bit perplexed...will have to look this up, but perhaps some of you already have.

With regards to the turbulent air behind a rotating wheel. In most race cars the rule is to provide as clear a path for the air that interacted with the wheel as possible. You'll see vents immediately behind the front wheels, as well as tunnels for the rear wheel air. I see this as a solution to two problems, wind drag, and brake heat. However in some cars I see fairings that approach the ground located immediately behind the wheel and come to a sharp taper behind the wheel.

So the question is, which of these will result in better aero?

*On a low-drag car the wheels constitute half the air drag so fairings play a critical role in drag reduction.
*Hucho says that their integration into the body is crucial if truly low drag is to be achieved.
* You can look at my trailer project to see the extremes I'm going to to cut drag.
* Solar racers and university MPG champion cars are good models from which to base fairing design.