Front Wheel Skirt Experiment

[hawkgt647]

Vehicle - 2005 Honda Insight

Goal - 1.)See if Coroplast will work as a front wheel skirt
2.)Is the aerodynamic gain measureable in FE

Concerns - 1.) Coroplast rubbing on tire and melting
2.) Retraction system failure and wheel skirt gets ripped off in the airstream

To address concern #1, I glued thin sheets of white Teflon to the rub areas.



The retraction system is simply a latex glove cut into strips and doubled up to give the proper tension.

Also installed a small block at the front of the wheel well to prevent the skirt from being pulled in too far.

Tomorrow's commute to work will be the first test run. It's a known course, with a years worth of fuel economy info. I'll see if it's measurable. I'm guessing it won't amount to much.

I'm bringing a few tools just in case they fail during the drive and have to be removed.

[MetroMPG]

cool stuff.

have you road tested these yet to any significant speed? what's the max speed of your commute?

edit: just re-read and saw you haven't tried it yet. good luck tomorrow - i hope that latex is taut enough!

[hawkgt647]

The drive to work in the morning will be the first test.

Will they still be on the car when I arrive?
They have to withstand 55MPH max and lots of turns.

[MetroMPG]

i don't want to sound pessimistic, but i think there needs to be quite a lot of tension to hold them flat against the car at 55 mph. at that speed, if they lift away just a little, they'll be off in an instant.

i think you'll be okay for the turns, since you'll most likely be below speeds that would be a problem (on/off ramps notwithstanding).

[MetroMPG]

seeing this makes me wish i could do this kind of stuff full time! looking forward to your results.

[SVOboy]

Personally, I think they'll fly off.

My idea of front skirt was always just see how much we could cover before the wheel starts to hit it.

[hawkgt647]

The drive to work this morning was the first chance to test the wheel skirts.

At first I could hear the skirt flapping and slapping the wheel well stop. Speed was 38-40 MPH.
Then it got quiet after I picked up the speed to 48MPH.

Arrived in the parking lot at work, got out to see how it looked.

Oops! No front wheel skirts. They sheared off at top folded hinge. Coroplast won't hold up to the forces and the retraction bands need to be much tighter.

Lesson learned. Back to the drawing board (cafeteria napkin).

[JanGeo]

Someone got a load of coroplast in the windshield!! LOL Didn't you see them fly off???

You may want to add an overlapping piece of material over the leading edge of the cover taped to the front bumper/fender in front of the wheel so that the leading edge of the wheel cover can not scoop air into the wheel well. You may want to make it a two part wheel cover allowing the front part to hinge on the leading edge on the fender ahead of the wheel and keep a vertical overlaping seam at the center of the wheel so that only the front edge opens up when the front edge of the tire sticks out and the rear edge opens up when the rear edge of the tire sticks out.

Think in terms of the air flow not gravity for your hinges. Also you may only have to cover the edges of the wheel well close to the tire but not over the tire if you have smooth wheel covers. This way the cover would not have to move when the tire protrudes - slight tradeoff but much easier to fasten and retain on the car.

Sort of like stuffing a really big tire in the fender so you can't get your hand in there between the tire and the fender opening like the guys say on the xB forum - if you can fit your hand in the wheel well your tires are not big enough!

[MetroMPG]

Originally Posted by hawkgt647

Back to the drawing board (cafeteria napkin).

that's too bad. i still think it's a worthy modification and hope you can make it work.

[95metro]

Well, I'm pretty certain something like this would work, but it would take some ingenuity (and wheel clearance) to get it strong enough and to make it fit. It's the only way I would personally feel comfortable doing it.



Basically it's just a framework that would be attached to the steering control rods so the framework would turn with the wheel. Well, at least it gave me the idea of plexiglass or lexan wheel skirts while I drew it up...

[Matt Timion]

Originally Posted by 95metro

Well, I'm pretty certain something like this would work, but it would take some ingenuity (and wheel clearance) to get it strong enough and to make it fit. It's the only way I would personally feel comfortable doing it.



Basically it's just a framework that would be attached to the steering control rods so the framework would turn with the wheel. Well, at least it gave me the idea of plexiglass or lexan wheel skirts while I drew it up...

Wow... you just sent my brain in about 200 different directions with this. this could really work. This would also work as a way to make the rear wheel skirts even more simple.

I just need to learn how to weld.

[95metro]

The actual structure could probably be torch/solder welded if you used copper tubing or electrical conduit.

But, yeah, getting it welded to the A-arm (or whatever) would need something more solid. You'd probably want a fairly complex framework using 1/2" to 3/4" tubing. My "brainstorm" drawing is with 1.5" - accidentally punched in .75" radius instead of diameter.

[95metro]

Oh, right - and you'd have to see how it would react over rough terrain. You wouldn't want it crashing into the wheel well when the shocks/struts compress.

Like I said, it would take a fair bit of planning and work, but I think the results would be worth it - both in functionality and in vehicle appearance.

[95metro]

Did some checking for pipe and tools - it would be pretty cheap to do. 3/8" pipe would be just fine. A 3/8" or less pipe bender is only $15 in my area, a cutter is $10.

Aluminum tubing would probably be the absolute best - weighs less than a pound for a 12 ft length of 3/8", .050 wall thickness. I think you would only need 8 ft per skirt frame. Not sure about the price of it - $3 a ft maybe?

There could be cheaper materials with thinner sidewalls that may work better.

[JanGeo]

You don't want to be adding weight to the suspension - the forces involved in a bouncing wheel are very great.

[SVOboy]

You don't want to be adding weight to the suspension - the forces involved in a bouncing wheel are very great.

I think the pound or two added will not be so great. Many people to brake swaps on my car and have never had an issue adding 20-30 pounds of **** besides insane braking.

[cfg83]

Hello -

I posted on this thread :

http://www.gassavers.org/showthread.php?t=1539

This thingy :

http://www.adcaps.com.au/pages/about.html

Question : Why not *extend* the cover beyond the diameter of the rim? Since the wheelwell must accomodate the wheel, it should accomodate a larger wheel cover. For the point of argument, let's say a cover that exposes between 1 and 2 inches of the side of the wheel only. Here is a before/after example of what I mean :



Problems : Hard to get your hands on these unless you have a taxi driver friend. System may not attach to small rim of Honda Insight. A flat tire would almost invariably SHATTER the (better be plastic!) cover because the current design is "defended" by the real tire rim. Maybe this is an excuse to go with 18" rims (heh heh heh, just kidding, the tires for those things go flat driving over ice cream).

This may be a no-show solution, because I still don't know IF the turbulence between the wheel and the ever-so-close wheel cover will be a big negative factor.

This does not give you the perfect cover that you want, but I think it is a safer compromise.

CarloSW2

[ZugyNA]

* might try some air tabs on the leading edge and use the air flow to help hold them in?

* some scrap innertube rubber could be cut in strips in order to get the right tension? ........farm or truck tire place.

[onegammyleg]

If it was a rear wheel drive car you could make a wheel cover disc with a threaded nut on the inside centre and wind it onto the end of the stub axle.
The hub cap would be able to be within a coupl eof MM of the rim at all times no matter what th esuspension or tyre is doing.
Plus its mega cheap to do.
Of course with most front drive cars its impossible as the stub axle rotates with drive.

PS , I think front drive is doomed for FE.

[Silveredwings]

Originally Posted by SVOboy

Personally, I think they'll fly off.

My idea of front skirt was always just see how much we could cover before the wheel starts to hit it.

I think Ben ran over and ripped them off when you weren't lookin'

[onegammyleg]

Hi theclencher - ¨How do you figure?¨

FWD cars only came about because its easier and cheaper for construction.
Sure , done rite they also give greater passneger compartment space as the trans tunnel is removed , although on cars that come in 4WD varient this is often not true.

In the beginning of FWD cars there was a few different engine transmision layouts tried.
The old mini was around as was the FWD Renaults (12) at the same time but the design ideas of both of those cars have been dropped.
The Fiat 128 was the first FWD car that was actually successfull and that plan is the basis for every FWD car to follow.
The engine was set east/west and had the transmision in direct line with the crankshaft.
The whole power plant assy was in front of the driver and between the suspension assy's.

Unfortunately --- This makes for wide cars.
Check out the figures for the track (between the wheels) for almost any 4 cylinder FWD car and then compare it to say a '70 MK1 ford escort.

I would bet a bag of peanuits that the escort was 20CM narrower than a Fiat 128 even tho it was a bigger car.

So . my beef with FWD is that most cars have a greater frontal area now days than they normally would (and push more air) have had if we had stuck with the RWD format.


PS . and in most FWD cars the height of the engine forces a high bonet line too., unles steh engine is layed back , A LOT.

[onegammyleg]

¨I would not call Festivas, Metros, and old Minis "wide".¨
They are if design progresion moves toward single inline seating streamliners.
Motro's are narrow because they use a 3cyl engine (not too good if you want to tow a boat) and old Minis were narrow becaiuse of archaic suspension designs and a combination transmision in sump arrangement , another idea thats been abandoned (in cars)

¨If a narrower car were desired, a 2 or 3 cyl, or V4¨
Both 2 ,3 and 4 cylinder engines dont have overlapping powerstrokes , so they tend to be less used because of vibrations.
V4 engines were mostly abandoned back in the 70's , they just dont work well.

¨traction advantages of FWD are too good to be ignored¨
FWD cars have far less traction on acceleration compared to RWD , havent you heard of weight transfer ?

¨Also the drivetrain package is inherently more light, compact, and efficient¨
Baloney - there is not much difference , and if manufacturers had been developing small RWD cars for the same amount of time they have been with FWD they would have dropped that weight- (eg , with carbon fiber prop shafts).

¨the Subaru flat cylinder configuration while retaining FWD could be adopted¨
Subaru's way only works because they use a flat 4 boxer engine (similar to the old VW beetle).
This means that the engine is not much longer than 2 cylinders.
SAAB used to do it also but with a 4 cyl engine and pointing backwards.
They have abandoned that idea.

In a typical family sedan (camry etc) with a real engine it dictates a wide engine bay.
It is possible to get a narrow FWD econo car , but it gets harder to do as the suspension has to go sumwhere.
I doubt auto manufacturers will ever go that route as it would force a whole revoltuion of what buyers will acept as a car - and I dont think average Joe ever will change.

I think he will walk b4 buying a 300cc streamliner.- and thats why these concept cars always stay just that.

[red91sit]

Originally Posted by onegammyleg

Hi theclencher - ¨How do you figure?¨

FWD cars only came about because its easier and cheaper for construction.
Sure , done rite they also give greater passneger compartment space as the trans tunnel is removed , although on cars that come in 4WD varient this is often not true.

In the beginning of FWD cars there was a few different engine transmision layouts tried.
The old mini was around as was the FWD Renaults (12) at the same time but the design ideas of both of those cars have been dropped.
The Fiat 128 was the first FWD car that was actually successfull and that plan is the basis for every FWD car to follow.
The engine was set east/west and had the transmision in direct line with the crankshaft.
The whole power plant assy was in front of the driver and between the suspension assy's.

Unfortunately --- This makes for wide cars.
Check out the figures for the track (between the wheels) for almost any 4 cylinder FWD car and then compare it to say a '70 MK1 ford escort.

I would bet a bag of peanuits that the escort was 20CM narrower than a Fiat 128 even tho it was a bigger car.

So . my beef with FWD is that most cars have a greater frontal area now days than they normally would (and push more air) have had if we had stuck with the RWD format.


PS . and in most FWD cars the height of the engine forces a high bonet line too., unles steh engine is layed back , A LOT.

We've arleady covered the width thing, so i'll move on the the high bonet line. Ever seen a 1988-1991 Honda Prelude? I'm 5' 4" and my knees were above most of my hood, and yes it was FWD.

Now look at modern cars, wow the hoods a lot higher! Not because the motors are larger, it's more for the safety of pedestrians. Yup, that's right something about having a higher hoodline makes vehicles safer for running into people. I'm 90% sure this is a new goverment regulation.

Weight? how can you argue this one?

FWD - Transmission, Intergrated differential housing, CV's
RWD - Transmission, Driveshaft (with power sapping joints), differntial and mounts, CV's

Even if the driveshaft didn't weigh anything, the RWD would still be heavier due to the differential and the beefed up area holding it.

Traction? I don't hear a lot of people complaining about burning out all the time. ha ha. In winter weight transfer can't beat weight already there, and FWD are a lot easier to maneuver. (just talk to any S-10 owner about that one)

Balance? lawyers know understeer is safe. Going backwards? not so safe.

Tradition/Average Joe? if this was the case everyone would still be driving RWD, V-8, carb'd, boats (like me ) If we do get them to buy streamliners? I"im sure they'll be just as wide as a motorcycle, which conveniently use horizontally opposed 4 cylinders Which would make a great drive line for a 2 seater tandem sporty "streamliner" Unless it's going to be skinnier than a few feet wide. But then it would pretty much have to be a motorcycle again.

Now we CAN stick the motor in the back MR-2 style, but this really doesn't have any advantages compared to being in the front. (economy wise)

I don't mean to argue, I'd like to hear your counterpoints, but please make sure they are correct.

I attached a picture of the prelude,



The hood could not be any lower because of the 14 in. wheels, not the motor. Stick some 12's on there and you get a very ugly car, AND a lower hood

[JanGeo]

Well my xB is really tall in the hood area and the oil pan is about as low as anything on the bottom and the engine cover is pretty close to the hood but it is not very deep so the hood is short with plenty of crush zone between the engine and fire wall. The Geo was a low hood so low in fact that you couldn't see it when sitting in the car which made steering really weird and finding light poles while parking some what damaging to the bumper. One good thing about FWD is that the entire drive train gets warmed up rather quickly by the engine and there are less seals that can go bad - anyone ever drop a drive shaft in a rear wheel drive car, have a leaky tranny seal or blow a universal joint? Width is engineering and better for stability.

[omgwtfbyobbq]

Yikes, no need to go that far theclencher. Besides, stating that auto design is based on engineering limitations is kinda ignoring all sorts of consumer demand issues.

[red91sit]

anyways, back to the topic, what if you placed a thin ramp thing right before the flaps? that way the air won't try to get between the flaps and the fender it will go up over it, perhaps a few squares of velcro to help keep it closed as well?

[onegammyleg]

Hi theclencher - ¨Narrow high FE FWD vehicles are not only possible, in many cases they are the most sensible layout.¨

Really ?! ..well , explain how using conventional engine components (as we know it) are going to fit a FWD engine and gearbox assy into the 1L/100k Volkswagen concept car.
Its going to be hard considering the whole vehicles width is less than the length of say a Camry engine and gearbox at 1.25m.

So your assuming that manufactureres will continue with boxfish style bodies instead of streamliners.
This might be possible to do and use some conventional compontnets , but will they get supermilage from them , not likely.

The Mercedies boxfish FE car isnt all that FE.
¨In the EU driving cycle the concept car has a fuel consumption of 4.3 litres per 100 kilometres¨ (average)

All that I have stated was that if auto manufactures try and keep cars in a similar style to what we have then it is unlikely that super high FE cars will be produced any time soon.
Super FE cars can not come from evolution of a design principle that has always had a disregard of fuel consumption.

In my view auto design has gone down the wrong road , and to change directions they will have to rethink a lot of what they have done.

[JanGeo]

Oh I totally agree that conventional auto design will not get us to the "high" mileage vehicles we expect. I don't expect the auto industry to be able to change tooling and design concepts in the near future so it will be up to new small companies to impliment the change and build the next generation of vehicles as well as the weekend garage car builder!

[onegammyleg]

Hi JanGeo .. I agree with your message

BUT- ¨so it will be up to new small companies to impliment the change and build the next generation of vehicles¨

Unfortunately that wont happen.
If you havent already seen it - Go to the video store and rent out ¨Tucker¨
Its the true story of a small car manufacturer that tried to make a differnece by making advanced cars.
The big auto manufacturers squashed him.

It happend b4 , it would happen again.

Ime not a pesimist , but the little guy cant win in a society that is driven by profit and greed.
We will get high FE cars only when the auto manufacturers can see a profit in it.
The state of the worlds environment and public opinion has nothing to do with what car makers make.
They make what they can get a good profit margin on and to tool up for a totally new idea would cost too much (to them)

I think the story will go ¨Yeah we tried these economy cars but coudlnt make them reliable¨ or something like that , some lame exscuse.

And a typical US buyer (like theclencher) that has no idea will suport the auto makers in keeping the big cars.

Here in my country there are no big cars (my metro is classed as a little smaller than normal family size) , so we are likely to adopt real FE vehicles many years before America does.

In my country of birth we were trying to start a company making replica Lous 7's.
I submitted about a years worth of devolpemnet in engineering work to the government and finnaly got there OK to build them.
Although they gave the Ok they did put one eeny weeny clause on it.
That was that my company would be perpetually liable for accidents involving my car.

So we went to the lawers and it was impossible to get around , to be forever liable for something not under your controll.
Insurance costs would effectively double the price of the car., thereby making it unsellable.

Even if it would be possible for a backyarder or small manufacturing company to build a new FE car , it will never be possible due to government restrictions., and likely it would never hit the road.

Thats life.

[onegammyleg]

Hi theclencher

Hey , but you said before ¨more light, compact, and efficient' , now you changed it to ¨are more compact and integrated, you simply cannot deny it¨

Those two statements are totally different.

We were talking about FWD and the area of the engine and transmision is very similar to that when used in a front engined RWD format.
The only difference is the space and weight required for a connecting prop shaft down to the rear end., and a litle extra for the diff's axle tubes.(which the same amount of material is often still found in the rear suspension of a FWD car- no saving here)
With modern materials the difference in weight is minor., and with a front engine rear drive format it allows more flexibilty in design over FWD vehicle as we know it.

Just because the engine and transmision are at the front end of the car doesnt make them in any way more efficient.
An effiecent use of space maybe , but this is with THAT adopted body design , if you use a radically different body shape or style and that advantage is gone.


¨it has more in common with Super-High Mileage Competition vehicles than regular cars.¨
Well ..if the majority of car buyers have this view then there is no hope.
If we are stuck with conventional format vehicles then there is very little room to advance.