Alternative to wheel spats and smooth wheel covers?

[ESmooth]

I did a quick search and didnt see this posted, just thought I'd share a random idea I had to reduce frontal area caused by the leading edge of the tires.

Why not take a motorcycle fender with a very aerodynamic shape and attach it to the spindle of the car. Since the fender would be mounted to the the suspension, it would move through the complete arc of travel while maintaining the same distance to the road. That way you wouldnt have to worry about exposing more or less tire during compression and rebound. It could also reduce the need to run a smooth wheel cover if a compete fender blank was used like this:



In some ways this could also eliminate or reduce the need for wheel skirts if the trailing edge of the fenders were also curved to improve airflow while taking care of the issue of allowing extra space for the wheels to turn since the cover would turn with the wheel.

This idea comes by way of airplanes and the Aptera, but I see no reason it couldnt be adapted to a car with fenders, other than some possible mounting issues.

Any thoughts?

[aerohead]

Ford did this with the front wheels of their Probe-IV concept car.The inner fender was full dimension,completely covering the wheel/tire.It in turn pushed against a deformable and elastic polyurethane membrane which completely covered the wheelhouse.

[ESmooth]

Hey, good to know its not a completely useless idea I guess. Heres a very rough photoshop to give the idea of what Im thinking:



Im sure someone with some metalworking skills could do a complete shroud even with nice tapered trailing edges.

Might even be easier to adapt aircraft wheel fairings:

http://www.aircraftspruce.com/menus/...lfairings.html

If the tapered trailing edge sat low enough it would probably even clear the body while turning and during compression

[SVOboy]

Sounds like an interesting idea. I'd like to see someone give it a try

[aerohead]

Originally Posted by ESmooth

Hey, good to know its not a completely useless idea I guess. Heres a very rough photoshop to give the idea of what Im thinking:



Im sure someone with some metalworking skills could do a complete shroud even with nice tapered trailing edges.

Might even be easier to adapt aircraft wheel fairings:

Wheel Fairings from Aircraft Spruce

If the tapered trailing edge sat low enough it would probably even clear the body while turning and during compression

Since the outside diameter of the inner fenders on the front tires are larger than the tires,you might run into interference with the existing wheel opening on the front fenders during hard lows-peed turning.Beyond that I think you're good to go.

[NeilBlanchard]

Hi,

In my scan/reading of the Hucho book, they mention that minimizing the air around the (rotating) tire/wheel does help lower drag. The tire itself is churning the air around it, so if the volume of air that the tire is moving is reduced, then that can have some effect.

The challenge is to deal with it as unsprung weight. The forces that will be banging it around will be fairly strong, and the added weight will affect the ride/handling somewhat.

[evolutionmovement]

Also interference issues within the wheel well with the suspension and chassis, especially with the very common MacPherson strut. People get rubbing issues frequently with struts or fenders just by bumping up the width of the tires a size or two. Maybe just using the outside half and running a bracket to the spindle would make it easier. Would leave a little more room to for clearances anyway, though it would still have to sit within the fender line.

[stevet47]

Trailer fenders with a sheet metal face added to the exposed side, attached to the spindle should do nicely.

[Bicycle Bob]

I built the inner fenders of my trike that way, partly to recover the space needed for full-lock clearance of regular inner fenders. Adding some support from the outside of the hub was helpful, so FWD is more challenging. I used fiberglass, with a seam at the largest diameter for wheel access, and integral ribs in the inner section. I think they would work OK even with slots for MacPherson struts, etc.

[moorecomp]

Originally Posted by Bicycle Bob

I built the inner fenders of my trike that way, partly to recover the space needed for full-lock clearance of regular inner fenders. Adding some support from the outside of the hub was helpful, so FWD is more challenging. I used fiberglass, with a seam at the largest diameter for wheel access, and integral ribs in the inner section. I think they would work OK even with slots for MacPherson struts, etc.

Additional support for a fairing may be obtained from using the bearing and mount from wheel spinner caps. Exploded view here: