Wheel turbulance Q for gurus.

[mustngr]

I have no graphics program as yet, so bear with my goofy descriptons.

Barring full wheelwell covers, could some measurable gain be realized by simply putting a " tire scraper" in the trailing edge of the wheelwell, located as close to the tire as possible and at the height of the loaded axle centerline (greatest diameter of the tire?)

My thinking is that the wheelwell can only eat as much as it gets fed.

[Bill in Houston]

I have wondered the exact same thing. I hope someone gives you the right answer...

[lunarhighway]

i doubt that would work, if i understand your explanation.

you mean something like this?:



(if you're looking for a free verctor drawing programm check out inkscape, open scourse and easyer to use than illustrator.)

i think the clearance would have to be so big the air would get trough anyway... it might create some sort of venturi effect...

but wheel well aerodynamics are still a mystry to me for the most part, so if you can fit this on your car you might give it a try....

the closest thing to this i know is a flap in front of the wheel. i'm not totally sure about how that works but i think it's there to help prevent wheel drag so you might want to look into that as well.

[Bill in Houston]

No, at the rear of the wheel, which would be at the 3:00 position on your drawing. The clearance could be pretty close back there.

[mustngr]

Originally Posted by Bill in Houston

No, at the rear of the wheel, which would be at the 3:00 position on your drawing. The clearance could be pretty close back there.

Zackly.


It's like an air diet for the wheewell, skimming off at least some of the turbulence induced by the tread.

I'm sure this has been looked into before, but if the principle is sound it could also be done in the front, though to a lesser degree.

[mustngr]

[QUOTE=but if the principle is sound it could also be done in the front, though to a lesser degree.[/QUOTE]

Just rethought this. If the flap were cut in a arc to match the arc of the tires during steering, the gain, if any, would be realized up front as well during normal corrective steering at highway speeds.

[omgwtfbyobbq]

Any area of relatively low pressure will still suck air in a cause turbulence AFAIK. Even if the back is blocked off, there will be air sucked in from what's flowing over the sides. This may create more turbulence since it'll suck in way more air from the relatively smooth side flow instead of the relatively chaotic underbody flow.

[brucepick]

I've always thought that most of what's happening around the wheels is just the shape of wheel plus the wheel well cavity moving through the space. I try not to be fooled by the fact that the tire is spinning.

I think there's a minor turbine effect due to the tread etc. but most of what's happening is due to the cavity with tire + rim in it. I did see some wind tunnel pics where a fancy alloy wheel created it's own turbulence that was much more than the same car with a fairly smooth and simple wheel cover over a steel wheel. FWIW.

[brucepick]

You need to chase down the wheel skirts built by basjoos and CO Zx2. Both have full front wheel skirts.

Basjoos' front skirts are hinged with wide rollers underneath so when he turns, the tire presses on the rollers and lifts part of the skirt up out of the way.

CO ZX2's uses stretchable rubber for part of the front skirt. I don't completely understand how it works; I think maybe the rubber stretches to let the tire do its thing. I don't know how/why there's no rubbing to damage the rubber, maybe he'll post here.

[GasSavers_bobski]

Originally Posted by brucepick

You need to chase down the wheel skirts built by basjoos and CO Zx2. Both have full front wheel skirts.

Basjoos' front skirts are hinged with wide rollers underneath so when he turns, the tire presses on the rollers and lifts part of the skirt up out of the way.

CO ZX2's uses stretchable rubber for part of the front skirt. I don't completely understand how it works; I think maybe the rubber stretches to let the tire do its thing. I don't know how/why there's no rubbing to damage the rubber, maybe he'll post here.

Hmm... Maybe this could be a legitimate use for "spinner" wheels and hubcaps. Instead of letting the spinner portion free-wheel like it's designed to, run a few U-shaped braces around the tire and anchor them to the steering knuckle. That way the spinner will be suported by the wheel, but won't actually spin with it. From there, you could attach hard wheel skirts to the spinner that would cover most of the wheel well opening... Scrapers could be attached as well. The skirt - being attached to the steering knuckle and wheel - would change angle with the wheel instead of colliding with it when steering the car.
The front and rear clearance relative to the fender lip could be a fraction of an inch, but the top would either need more clearance or have to be made of some kind of semi-rigid material like thick rubber. The top edge of the skirt might collide with the fender during typical suspension travel, and almost certainly would due to suspension travel while turning, thus the need for a flexible material.