How would you do front wheel skirts ?
 

We all seen Basjoos' front wheel skirts.
Very clever indeed !
Just curious though about how completely foolish that it would be to attach a wire cage ( a horizontal and vertical support which encases the wheel ) around the front wheel and have it attached to parts of the wheel assembly that move but do not actually spin.
I was looking at the area behind the wheels and thinking that this could be done pretty easily.

If done incorrectly though this could be disasterous !

Another option would be to get some of those hub caps that have a spinner section that rotates, but has an outside section that remins stationary.
You could then attach a full wheel cover to this non spinning section.

( I am much more comfortabl with this idea myself.)

The advantage to something like these two ideas would be that the wheel cover would not increase the frontal area of the car. They would both be flush with the sides of the car.


Your thoughts ?

I had read a topic like this before. I hope I am not reposting something that has already been covered.

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That's basically how the Ford Probe did their front skirts. They had a fender enclosing the wheel and that moved with the steering which pressed against a flexible stretchy urethane sheet that comprised the outer skin of the wheel well.

i wonder if you really need a full wheelwell cover, what if you combined moon hubs with a really tight wheelwell and close of the remaining space with some "brush" like meterial, like you find on the bottom of shop doors etc, to prevent draft. i've actually seen this used in the wheelwells of city buses, although i'm not sure if it was done for aero... some other flexible arc might work too.

taking this one step further these brushes could be applies to the bottom of the wheelwell preventing more air to move in from there as well. but also dirt and water wich micht in turn prevent corrosion, and splatters accross the sides of the vehicle.

it's not as "perfect" as a full wheel well cover but it's far more workable i think. the stress on the flexible parts would be far less than with a full cover.

thinking about it, perhaps brushes could also be used as airdams or other parts that are likely to break.

i'm not sure wher to obtain this kind of material though, but big doors might be a good place to start.

Lunarhighway - that's a great idea.
Thanks for mentioning it !

The brush material is used on the rear fenders of big rigs and trailers. I
believe it's to keep from kicking up debris on the cars behind/beside them.

Let us know how it turns out if you install some.

So when you do an image search for "wheel fairing" you get images like this

https://www.macsmachine.com/images/co...leftwpants.gif

Molds for something like this can be made somewhat easily.... Really, you could take the mold off the wheel (take it off the car) and then oversize it a tiny bit. If out of composite fiber -- I'd add a nice stiff rib from the mount point to the opposite side. Once you've made a mold of your wheel, cut away where necessary to fit your wheel hub/steering components.

To make it flush... I wouldn't increase the size of the wheel fairing itself. Instead, add a sheet that fits the wheel well.

Here's some awesome wheel fairings :)

https://www.speed101.com/images/sb/vi..._side_open.jpg

Keeps all that turbulence from spinning wheels contained ;)

https://www.speed101.com/images/sb/vi..._rear_open.jpg

Just for fun... Look at that cross section!!!
https://www.speed101.com/images/sb/virtualedge_top.jpg

Definitely awesome.
I hope he has some way to see out.
Or maybe a closed course with hay bales lining the perimeter!

So his vehicle is called "virtual edge" - it's not mounted in the photograph, but he's got a cooling system and LCD/video screen/camera :thumbup: As these vehicles typically don't have much in the way of peripheral vision, it's not that big of deal - as long as you can work with less depth perception :p

I think he raced at battle mountain -- which is a really long course with nothing to crash into (for the most part). Hay bales aren't necessarily "safer" as at 75mph, hitting a hay bale while sliding on your side.... :thumbdown:

69 year old skirts
 

Why make it movable? Make it fully inclosed, with room to turn..

https://www.thehenryford.org/museum/g...goldenrod1.jpg

Found this a little earlier :p
https://geekologie.com/2007/03/aptera...lk_1-thumb.jpg

A friend of mine is working on the Aptera, pictured above!

I think the skirts that surround the entire wheel are a grand idea. my first idea was attached airdams that stuck to the hub..

https://www.fuelly.com/attachments/fo...370b74dd20.jpg

But I'm revising the idea to shroud the entire wheel. Pics forthcoming...

I've got some time off for Christmas. The plan was to make some sheet metal bits on either side of the wheel well (attached to the car) to attach either thin rubber (I'm using pond sheet rubber) or lycra/elastane/spandex, if I can find some black stuff for cheap. The wheel should only rub on the extreme turns. I'll attach it with small bolts with washers on the rubber side. (This is within my technical capabilities, which is why I'm attempting it. I really need a shed with welding stuff to do much more.)

That brush idea is really intriguing. I'd love to see that done and pictures from someone else's vehicle on a wet day on a highway, at highway speed. I'd love to see if much air is still rotating and flicked outwards.

I'm thinking of shrouding the entire wheel with a close-fitting cowl that's attached to the wheel hub/tie rod end and base of the strut. It could come to within inches of the ground, and could show huge efficiency gains by shutting down the wheel well squirrel-cage.

The cowl will be split down the middle (long the tread of the tire) and held with dzus fasteners, for easy removal. I'd just bolt on the first half, slide the wheel on and bolt it, then fasten the outside over that. I can make the whole thing out of basic CSM fiberglass over a wheel-sized foam plug. This is exciting- I can't even imagine how good it could be...

I'd drive that aptera, are they working on a kit?

The 1985 probe v also has the shroud that moves with the front wheels, heres a good thread on the subject:
https://www.gassavers.org/showthread.php?t=4428#20



https://aycu03.webshots.com/image/232...4998816_rs.jpg

I've got to teach myself how to fibreglass. Good luck with it!

Remember to account for potholes with your design, leave more clearance than you want. It could get really ugly to have your cowl sandwiched between the wheel and the road, in busy traffic.

I've been searching for that brush strip material in vain. Has anyone else had better luck?

Why close off the back side of the wheel wells at all? remember you are trying to maximise the speed of the air going from the front of the car to the back, with an open part at the back of the well any air that is inevitably caught in the wheel wells will vent backwards rather than downwards meaning less drag and lift.

Check out the design of the area behind the honda insight front wheel well:
https://images.autobytel.com/view/aic..._exwheel_x.jpg
They curve in to allow as much air to go out the back as possible. If you can't block it off i wouldn't be too worried. It might be a better solution after all anyways ;)

Ps. Sorry to go off topic

Rather amazing how all of this has been tried before. In fact, it probably worked but passed out of fashion.

I like basjoos' roller skirts. My truck has about 1.5" clearance with the front wheels straight ahead. The effect is like popping a 'chute. With my smaller front wheels my wheel wells are huge. Gotta do something.

I thought about using fixed front wheel skirts, blistered out to clear the wheels at full turn. I rejected that idea because that imposed a 6" bulge in place all the time. That adds frontal area so it is no go.

I do still think of a very tight partial skirt. A partial skirt would cover about 30% of the opening. Mooneyes would clean up the wheels. This would probably be as much work as basjoos' movable skirts and would limit changing tire size.

It's going to be a production car, but registered as a motorcycle, I think. They're taking deposits right now..

Fiberglass is ugly... itchy, smelly, sticky, it' papier mache's evil twin. It's anything but difficult, though, just helps to have familiarity.

You're right about the clearance, especially if I intend to lower the car! I think if I make the shroud (and it's mount) sturdy enough I can keep it really tight on the tire--accounting for diameter change at speed. I'll probably use a version of the brush idea between the shroud and tire, to keep rocks from doing Pachinko inside.

It would really suck to get a flat tire and have the weight of the car distorting my carefully made shroud...

In that case, I wonder If just a partial front skirt wouldn't do the same thing. The idea behind this is to flare the front just enough to catch most of the air flung forward to diver it down and back, with nothing at the rear.

https://img92.imageshack.us/img92/572...fairingko8.jpg

My original idea was just to make two sheet aluminium pieces (or one big one), possibly with something to brace them out a bit underneath, maybe not. The idea was to give the maximum length of rubber so that an outwards stretch does not encounter much resistance and hence lowers wear.

https://img144.imageshack.us/img144/7...erskirtvn3.jpg

You might get some ideas if you research the Formula 1 cars of the late 1970s when sliding skirts were legal. A good one to start with would be the Lotus 79 which Mario Andretti drove to the 1978 World Championship. Be sure to click on the "ground effect" link.

I'm thinking if I shroud it all, it'll take care of turbulent air entering the wheel well from under the sides as well, and just provide that much less disturbed air underneath. Also, if I "bubble out" the wheel shrouds, I can have them flush to a partial rubber skirt around the wheel well. I'll have to draw that for clarity..

https://www.fuelly.com/attachments/fo...8ae17957df.jpg

Well, I spent four hours and managed to do something similar to CO ZX2's skirts. All the contact area is rubber, and underneath are two aluminum fairings to give enough clearance for the wheels at highway speeds while not adding much pressure drag. They appear to be rubbing very little.

We'll see how my next tank goes. Haven't yet tested it with both of them on.

That's cool! Your grill looks good, too.

When I saw cozx2's skirts, I was trying to think of the best surface to contact the wheel when it turns, and I thought of this slick synthetic bristle stuff you sometimes see on the backside of conveyor belt rubber, so it can slide over metal.

Does the tire grab the rubber much? I'm really curious.

If it's an issue, maybe it could help to put aluminum tape (or something better) around the outer wall of the tire, right down to the contact patch, so that when the spinning wheel pushes out against the rubber it's not rubbing the shroud raw.

Thanks very much! I thought that seeing as I was covering the grille area, I might as well smooth the contours a bit.
That would work, if it could stretch, otherwise you'd have to have two segments of bristly stuff. The idea with this is that the rubber is so long that it doesn't need to stretch much. If I could use a more stretchy material, I would. I thought it would be easier and cheaper (over the short run) than to go with the more complex but complete Basjoos type solution. As to put something more abrasion resistant there, I thought I'd try and minimize the abrasion first (maximize the length of rubber) and see how long it holds up. It was only $30, and I used only half of it.
No, it doesn't (as far as I can tell). Not anywhere near what I was expecting. I should probably have someone look at it. The thing is, at extreme angles the speed is always relatively slow, that's got to help.
I'd worry about the tape getting cut and developing a more abrasive edge than the tire.

What I'd really like to figure out is a way to cover the leading edge of the rubber skirt without looking overly tacky. At the moment, the bits in between the screws can catch a bit of air. Got any ideas? I'm not sure if I've even seen aluminium tape, maybe that would work. I was thinking of something to either match the paintwork or the rubber.

A few updates: Coast down testing yields something in the area of 0.22-0.25 area. I really need to get elevation data to do proper testing. I just checked bom and at the moment there is a 13kph headwind in the area I did the testing(gotten by averaging two sites in that vicinity), virtually a straight headwind. Note I only did it in one direction, starting at sections of the road that were roughly flat I thought.

If I take that into account (by increasing my speed in my simulation to account for the increased headwind), I get a drag coefficient of 0.17 to 0.19. It's possible that the wind has picked up since then, but it was only an hour ago since I got home.

Suffice to say, I think front skirts are a definite improvement. The lower road noise is noticeable, and coasting seems more effortless than it was. Probably the acid test will be when I do some terminal velocity glides down some hills on my commute - typically I see 80-85kph going down them.

Someone yelled out "What's the go with the car, mate!?" at a set of traffic lights. I said (before doing the testing) "The drag coefficient is about 0.22". He probably didn't know what I meant. I guess I should have said "fuel economy!". Oh well.

I still have had no issues with rubbing.

And I think my solution to the front of the rubber/car join will be industrial strength UV proof clear tape.

What do you mean by that?

The UFE-II is smooth, but it's not a miracle. There are several glaring concessions to fashion.

The grille area is approximately 5 or 6 times as large as mine. That's 5 or 6 times as much air that has no choice but to create more turbulence, and hence heat, and hence, wasted energy that game from the car's kinetic energy. Small in area, large in Cd.

The front wheels are not only unfaired, they are also egg beater style. Not only that, they are relatively large. This creates drag, a lot.

You also have the rear of the vehicle that is no less than 2/3 of the car's total frontal area. This is comparable to the back of my vehicle.

My car is not going to win any auto salon prizes any time soon though.

Do note that I will be retesting my frontal area, and most probably, the coast down. But as far as I can tell, there is a noticeable improvement by doing the front skirts, which is what you would expect.

The safest method is a tight fit at the front of the wheel. One important thing to remember is that the wheel moves. Another less obvious thing to remember is gas mileage in turns is amost inconsequential. A good tight fit when straight ahead will give th best safety and fit, then vent the high pressure area behind the wheel through the fender. The fender vent will also help vent high pressure air from engine compartment.

I don't get it
 

Maybe I have been looking at the wrong threads or something, but wouldn't front skirts kinda hinder turning the tires?

M

You'll get great mileage as long as you travel in a straight line... ;)

the front fender skirts actually flare out so that the tires can turn. here is an example. sorry about the bad example but it was the best picture I could find.

https://www.metrompg.com/posts/xfi-aero-car.htm

Basjoos didn't flare his so much, he used rollers and hinged the skirt so when the wheels were turned too far, the skirt lifted up.

https://ecomodder.com/forum/showthrea...4-0-a-290.html

https://ecomodder.com/imgs/aerocivic/CivicBd.jpg
https://ecomodder.com/imgs/aerocivic/CivicBc.jpg

Quick dirty and almost done.
 

Here is what I did last week end.

I thought about how to do front wheel pants for way to long. I kept thinking about the best hinge and the best roller and finally said the heck with both. I just riveted some scabs to the rings which I had used to close up my wheel well gaps. I did not use hinges and I did not use rollers. I only have a couple hundred miles on them. The tire just rubs on them and the fiber reinforced material from Home Depot just flexes. The verdict is still out but so far I like them. I will need another metal strip on them to hold the shape a little better. I can turn about 1/4 turn of the steering wheel before contact. There is not much noise except when turned to the stop and doing a tight turn. The bungee cord helps hold them in. They are not finished but I finally have some front skirts.

Ernie

aren't you going to get quite a bit of tire scrub from that?

I would think that your side walls will take quite a beating over the course of a few years. new tires aren't cheap and will negate any gains.

I may be wrong but I would think you would want to do something so that it didn't rub away the rubber.

I agree with BEEF; some small rollers would make all the difference.

They look great, though. :thumbup:

I appreciate the concern about the tire sidewalls rubbing. The tires are old and should be replaced. I intend to run them long enough to get a good estimate of the wear rate. My tires rub on the payment too and they have held up pretty well there. ;)

just be prepared to purchase new tires on the spot.

I know that there is some scrubbing on the tires when you turn your wheels or during breaking but you aren't scrubbing with the intensity of a die grinder.

your wheels are going to be moving possibly 60+ mph when they are rubbing. this could be the equivalent of a sand paper disc against the side wall depending on the dirt or other material either on the fender flare or on the tire.

also remember that in states where they have anual inspections ( I think there are still some that don't require it) they check your tires and side walls as well. not sure what they would say about scuffed up side walls. I do like the roller idea though the skirt would have to protrude out farther to get the roller in there. you could just use a wheel instead of a roller.

good luck, and make sure that they are removable in a pinch.

*edit* another idea, and this is a whoom dinger, is you could put a housing around the tire that turned with the tire. I heard someone mention that some concept car had done this. you would mount it behind the tire like where the caliper sits which also makes it stationary when the tire is spinning but it would turn with the tire when you turn. you could shape it so that this piece would contact the fender flare instead of the tire so that you wouldn't have the rubbing. that would make for a lot of fabrication though and a lot of time spent. like I said before, this idea is really out there.