concept cars aerodynamic
 

I have seen more images about citroen C-Sportloungue and the Lotus "circuit car", and I have noticed the way in which the planners they have decided to isolate the front wheels aerodynamically.
some image:

https://img503.imageshack.us/img503/8680/c1dr9.jpg
By fabrio at 2007-07-22

https://img267.imageshack.us/img267/8407/c2xi4.jpg
By fabrio at 2007-07-22

https://img408.imageshack.us/img408/4449/lotuswz5.jpg
By fabrio at 2007-07-22

about the lotus, from https://www.gglotus.org/ggrace/circuitcar/circuitcar.htm
You can read:
"#

Aerodynamics
# Flat bottom with front aero splitter and rear diffuser
# Aerodynamically designed body shape with minimal drag and frontal area
# Single plane rear wing, high downforce, carbon composite, dual element rear wing (optional)"

and about the citroen from:
https://car.kak.net/modules.php?op=mo...ticle&sid=4660

You can read this one:

"Optimised aerodynamic design

Special attention has been paid to the aerodynamic, flowing lines - strong Citroën values. The drag coefficient is 0.26 and rear lift 0.02. In addition to styling and volume that enhance air penetration, various technological features contribute to that result:

- air ducts on both sides of the front bumper. They produce an air flow through the front wheel arches, creating a virtual fairing.
- an electro-mechanical system at the rear of the roof. It consists of micro electro-mechanical systems (MEMs), which create a virtual airfoil by propelling jets of air and substantially improve the vehicle's drag and stability at high speeds.
- a reverse mobile airfoil, under the structure at the rear of the vehicle. This cylinder-activated reverse airfoil improves lift and enhances vehicle stability at high speeds. It has three positions:
- a "neutral" position, integrated with the rear styling, when the vehicle is stationary or in the city,
- a position adopted at a cruising speed of above 90 kph that optimises the drag coefficient and lift,
- a position activated during emergency braking to increase negative lift by adding support and stabilising the vehicle.
- the smooth subframe improves both drag and positive lift by optimising air flow under the vehicle.

This capacity to penetrate the air enhances the C SportLounge's efficient, dynamic handling, performance and environmental-friendliness."

Now, second you, this system in order to guide the air around the wheels is better or worse to the classics flow shunters?

for examples this?

https://img116.imageshack.us/img116/478/f2tx5.jpg

It is possible, to install this particular system of air guide?

wheel aerodynamics is a complex matter, and i'm not sure i fully understand it, but i'm sure there are ways to improve the airflow trough the wells.

the citroën seems to have two separate ducts. i think the lower ones are for break cooling and the upper ones seem to vent air into the upper wheelwell.

the second car seems to have one intake, but it might split internally to do the same.

i read somewhere that a lot of wheel drag is assosiated with the fact that the airflow follows the direction of the wheel. at the back of the wheel it's carried upwards into the wheelwell and than forward at the top of the wheel and than down again there it meets the oncoming air at the botton of the bumper. wich is partly why fairings (like you made) should work.

letting air into the wheelwell at the top might change the pressure and provide a better aerodynamic situation.

anyway that's what i've pieced together from things i found on the web, i'm not sure if what i say is right.

i think citroën's are a good source of inspiration (maybe production cars even more then concept cars) , because they have a long history of innovative cars and their FE is very good. the classic citroën DS for example has a completely flat underside and variable ground clearance. try to find that on a production car today!

I suppose that, you refer at this image:

https://img516.imageshack.us/img516/8663/ruotahs5.jpg

about my job https://www.gassavers.org/showthread.php?t=4385, I have noticed an increase of turbolent flow noise, you think thats are necessary an modification?

please, read my other topic:
https://www.gassavers.org/showthread.php?t=4429

also this:
https://www.gassavers.org/showthread.php?t=4431

I would appreciate your comment.

thanks

ciao

fabrio

Increased wind noise is an indication of increased turbulence. As you decrease turbulance and drag, the car should produce less wind noise and become quieter.

YES!!!!

but the nois is increased!

My car has a huge space around the rear wheels within the fender well. It is not needed for suspension travel, and is not occupied by struts or springs or anything like that.

Would it
a)possibly
b)probably
c)probably not
be helpful to make some fender liners to reduce the amount of space? They would basically be the shape of the wheel arch.

what means?

and this ?
excuse, but I do not understand :(

I was asking a separate question from yours, but related to wheel well turbulence.

Aero Mod Infohttps://www.hotrod.com/techarticles/b...ips/index.html

ah... you can show to me a photo of wheel well ?

Sorry, my wife has the camera, and she is out of town for a week.

I saw a similar setup on a new Nissan truck today. At lest I think it was a Nissan, the guy so squirrelly about me looking at his truck so much and split.

As near as could tell the air entered the bumper through a funnel duct, then hit a solid partition and was directed to the inboard side of the tire. I'm not sure whether the partition is there as a "backflow" preventer, or just to keep road debris or mud from being flung forward into the duct at low speeds.

Anyone know?

Here's what I think is the main advantage of this sort of ducting. By directing airflow behind the wheel and out and down toward the rear of the wheel well, it would not eliminate the recirculating effect over the top surface of the wheel, but it would substantially reduce the turbulence at the rear bottom of the wheel as illustrated and circled in blue.

https://www.kipanderson.net/media/ruotahs5.jpg

There isn't much that can be done to eliminate the reverse airflow over the top of the tire, as the tread itself generates so much of this, only a totally smooth tire could really eliminate this.

Do you think that it is pretty much guaranteed that if my car had a cavity like the one shown, and I reduced it so that it was right at the rim of the wheel arch, that it would lower the drag? Smaller turbulent volume = better? Anyone?

The reason for those ducts is brake cooling, which a hypermiler probably doesn't need so much. Any aerodynamic gains of borrowing air from the front end to fill the wheel wells needs some actual testing. Aerodynamic changes in general need testing for every vehicle they are tried on (lots 'o variables).

IMHO, you should be looking at ways to improve on the following setup. No air? No problem:
https://www.gassavers.org/garage_imag...rbxlvpv29i.jpg

sorry skewbe, but I am not in agreement with you.

you read the my first post :

and
in both cases, the constructor speaks about dynamics fairing, realized through a air flow that it grazes the external part of the wheel: no brake and no flow internal to wheel!

this solution not is aerodynamically good that the ZX2 coupe of COZX2 (of which you have inserted its photo) , but permit full range steering, the COZX2 car, not!

perhaps you refer to one solution like this:

https://img510.imageshack.us/img510/1511/veyrondw9.jpg

I have opened a topic about this devices, look :https://www.gassavers.org/showthread.php?t=4431

if you intend like the posted photo, yes for me.

Imho, the arch cavity inhales air from bottom and it expels it out from front-upper the wheel like in photo:

https://img301.imageshack.us/img301/3...bolenzatv0.jpg

if the point is better MPG, COZx2 is on the right track with bonefied results. The "Constructor" has not provided anything but hype about speed holes.

Those "virtual fairings" need documented testing lest they be catagorized with the invisible pink unicorns :)

o yessssss....the job of COZx2 is fantastic, and your MPG confitme he.

about the virtual fairing, I haved only reported the declarations of constructor...one wave of inspiration!

fabrio, I beg to disagree with your statement on the ZX2.

ZX2 does permit full range steering, lock to lock.

Concerning your statement that the design is not aerodynamically good, the 1985 Ford Probe V concept car has the lowest CD ever for a 4+ passenger car. CD .137, Probe V was factory built and wind tunnel tested.

Probe V featured full wheel fairings, both front and rear.

1985 Probe V has been my guide in modifying my car, Old Reliable(CO ZX2).

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

very good, it wasn't clear if you were asserting this will help or asking, and really only testing will tell if a mod helps someones car or not. Inspiration=good, hopefully someone is inspired enough to try it and document the results.

Here's the probe CO mentioned, kinda looks like old reliable too ;)
https://www.geocities.com/conceptcarc...oit_probe5.jpg

oh, oh!

sorry: repeat, my Engliss is bad :)

your aeromods is fantastic, I think: aerodynamic of your car is MORE good of citroen!

"front splitter" of citroen isin't good lyke the front skirt of your Old Reliable.
it is comprehensible now?

I did not imagine that your machine could steer well therefore....sorry, can you post an image with turned steering please?

fabrio, here you go. Light not good for left side photo.

Fully turned, outside edge of tire is about 7" outside of fender.
https://aycu39.webshots.com/image/235...5805874_rs.jpg

Both pics taken with steering cramped all the way to the right.
https://aycu22.webshots.com/image/221...0478472_rs.jpg

fabrio, I would like to congratulate you on your research and comments. You have created a very interesting discussion here. Thank you.

My compliments to the seamstress. :-)

Bill, Virginia thanks you. We had some tense moments working on these together. We laugh now but we growled a little back then. No sewing now required. Found contact cement that works great and a heck of a lot quicker and easier. I have never had glue hold much of anything before!

skewbe, do you suppose your pic of the Probe could be a drawing? I don't think I have seen that particular pic before. There are substantial design differences shown in your pic and my pic, which I know to be a real car. Ford made a few, not sure how many, the grape car above survives today.

The Probe was a multi-year project for Ford. The engineers and designers probably changed their minds many, many times. I would like to see a photo of the Probe V with the front wheels turned. Must make quite a lump in that beautiful fender. Hope none of those designers ever see Old Reliable.

Thanks for your comments. Be nice to fabrio or he may make us talk to him in Italian language. Can you imagine that?

CO ZX2 -

I think skewbe got the picture from this website :

https://www.geocities.com/conceptcarcentral/

CarloSW2

Carlo, thanks. What a great site. I found info I had never been able to find before. Did you read the fine print for the various Probes? Motorized adjustable height air dam, rear body raised 6" at speed, and more. Wow!

I did not see skewbe's pic on the site, but I saw mine of the grape car.

I went to https://images.google.com and searched for: 1985 ford probe v

I was hoping to see the probe with its front wheels turned, I thought I saw mention of flexable panels, but those look pretty solid.

I was thinking the same thing...

CO ZX2, can you describe how the front skirt works? It looks like stretch fabric, and the tire would rub against it? Or maybe not, please do tell.

The black pieces are rubber inserts that stretch when turning, then return flat. The rest is 1/16 plastic which allows some give also.

The pics I put up are the extremes of lock to lock. Normal driving uses half or less of that movement. Highway driving touches slightly for very short durations.

A link for skirt construction:
https://www.gassavers.org/showthread.php?t=2173

skewbe and Bill in Houston:

Probe V had cages for the front wheels that turned with the wheels. Contacted the outer fender panel of flexible urethane.
Mine are plastic and rubber. Link above to construction.

Can you to connect the black pieces at the steering for eliminate the usury by friction?

fabrio, the friction is not heavy and is of very short durations. A skirt that moved with the wheel would be like a sail in the wind when turning at speed.

I have used these thoughout a nasty winter and I have assured myself of their durability.

sorry CO ZX2 :) I don not understand! the frictiono he higt or not?
and the duration?

:)

frictiono brevemente, frictiono no grande

ok skewbe....thanks ;)