My prototype wheel skirt

[vtec-e]

I'll take some pics tomorrow when it's light outside. The flare at the front is slight and i could have gone more. I don't know how well the foamboard will take to reheating so i might just leave it as is...for now.
Those are some interesting pics of similar skirts. It's kinda funny how i came up with the same shape without any outside influence! My reasoning behind it was the wheel arch tapers in a little towards the rear of the car but the wheel doesn't, obviously! So i slid a straight edge down the wheel arch till it touched the tire at both the front and the rear. This was going to be the lowest point of the wheel skirt and it was sloped as it turns out. If i designed it with an outward bow i would have ended up with a different lower edge. I'll still put a slight bow in it for aero and rigidity purposes and also to give me a little more clearance.
I haven't jacked up the car and removed the wheel yet but i'd say i'll be ok. At the very least i might have to tilt the lower part of the wheel in under the car to clear the studs and remove the wheel. If it's too fiddly then it's back to the drawing board. Should be ok though.

ollie

[vtec-e]

Originally Posted by MetroMPG

PS - you should add this thread to the Project Library.

Who? Me?

[Cd]

vtec-e , I think your covers look fantastic ( once painted. )
It just looks ...'right'.
I would suspect that your method is indeed a better way to reduce the frontal area of a wheel skirt, yet have attached flow to the back of the car.
You have a really tight fit all around, and I would think that air will slide right past the wheel without any real turbulence. ( Especially if the wheels are smooth ).

Disclaimer : I have no clue what I am talking about. What I said is pure guessing.

To test this though ( and prove me wrong ) it would really be interesting to see a tuft test around this area of the car ( hey - while you're at it you might as well tuft the whole thing. It's really quite interesting to see how air travels around your car ! )

[Cd]

After looking at the skirts a second time, I think the edges of the skirt should be tapered inward ( like the front fenders of the 1st generation Insight. This would smooth out the airflow behind the tire instead of acting as a parachute.
Do you dare to bring the edges of the skirt ( the sides ) even closer to the wheel ?
Since this is a prototype, you could even just use tape to fill the gap.

Perhaps I shouldn't have jumped to conclusions without a picture from a 3/4 side view. How snug is the skirt around the wheel ?

[aerohead]

The Renault Vesta-II concept used partial covers and still managed Cd 0.19 and 146-mpg.If you must compromise,then "you're there".Looks good!

[vtec-e]

I left a gap (at the dog-leg bit) of about 8 to 10mm to allow clearance for when the suspension compresses. More at the front as it turns out. I forgot to allow for the flare bit, which opened the gap a little. Since the axle is below the suspension pivot, the wheel will get closer to the rear dog-leg during compression. Not by much i'm sure but i wanted to allow for it anyway. I'll check all that tomorrow and take a few more pics. It'll be hard to take a pic while compressing the suspension though.....
Tuft tests! Yeah that is something i'd love to do. Well, making a video of them that is. I used to have a tripod that would be up to the job, a benbo trekker, but i don't have it anymore. I'll see if my current one will do the job. Otherwise a length of unistrut or something with a ton of duct tape. Yup.....sounds like it'll work!

ollie

[vtec-e]

Originally Posted by Cd

After looking at the skirts a second time, I think the edges of the skirt should be tapered inward ( like the front fenders of the 1st generation Insight. This would smooth out the airflow behind the tire instead of acting as a parachute.

Well spotted. I noticed that as i fitted it but just wanted to take a pic for here. As i stand over it i can really see how it protrudes past the tire. Certainly needs some heat to bend it in, which will tighten the gap too. Every little helps eh?!

ollie

[Cd]

Originally Posted by vtec-e

Well spotted. I noticed that as i fitted it but just wanted to take a pic for here. As i stand over it i can really see how it protrudes past the tire. Certainly needs some heat to bend it in, which will tighten the gap too. Every little helps eh?!

ollie

You plan to heat it ? I thought it was foam board in this prototype version.


Regarding the tuft testing, do you have anyone that can drive beside you and video ? It would save you the hastle of trying to rig up a camera rig.
It would actually take three people, since you need two people to drive and be looking at the road ahead.
Another option would be to have someone video from the side of the road as you pass by. Using a camera on a tripod would only capture a fraction of a second of the test since the camera would not follow your car, and it would ost likely be blurred.
Also, your camera might get stolen.

( Jut make sure they have a steady hand and know where you want them to point the camera. )

[MetroMPG]

You can tuft test by rigging a camera "boom" on the car aft of the area you're interested in. I did this to look at my rear skirts.

http://ecomodder.com/forum/showthrea...etro-3692.html

Just don't knee-cap any pedestrians.

[NeilBlanchard]

Hi,

The rear of my skirts do get some outward pressure, even without the "dogleg":

Since this picture was taken, I "rotated" the skirts forward, so that the bottom edge slopes up more towards the back -- and they *still* get pushed outward. To the point where the tape is getting lifted off of the fender...