Steelies or Alloys?

[digitaldissent]

as far as rotating wheels go, check this out;

I found it from another thread on here
http://www.fluent.com/solutions/auto...bile_wheel.pdf

[Chris D.]

I wouldnt think that having the vehicle stationary in a wind tunnel is any different than in motion..

your looking at the areodynamic properties of the vehicle, not its drive charactoristics..
Airflow is airflow across the vehicle.. measure your air speeds while doing 55mph then simulate that in the wind tunnel, apply smoke, see what works and what doesn't..

[Xringer]

If your rims are acting as air pumps, moving air out (or in) the side of the wheel,
then putting a wheel skirt over the wheel, may be like holding a solid plate 1/2" in front of your desk fan. The work load on the motor is going to increase.

But, if you had a Moon discs installed on your car? Would the the air pump even be able to start? Since the moon disc is spinning with the wheel, (and not fixed relative to the wheel, like the skirt) the air under the disc shouldn't be moving much and not be a factor at all.

Yeah, it sounds real logical that a skirt should be used with discs.

Did those Gassavers guys that had poor skirt performance have moon discs installed?

[i_am_socket]

Not from what I could find in the article

[Cd]

Originally Posted by trikkonceptz

OK we seem to be the DIY kings, so what would it take to build a wind tunnel? Can a body shop spray booth be used? In which case what kind of air speeds are necessary to obtain results? I am sure we can build the contraption to blow out smoke in streams ...

http://www.aerodynwindtunnel.com/a2.html

Budget wind tunnel for the common man.

The fellow that runs the place worked on the EV1, so he knows what he is talking about.

[aerohead]

Its a good question and all I can do is relate what I experienced with the CRX.Michelin was touting their Green-X tire in the mid-nineties.Claims were maybe 4-5 % better mpg.They were not available in 13-inch wheel,so $1,000 later I had a set of 14-inch alloy wheels off a CRX Si and Michelin's new wonder donuts.The whole thing was a bust! I never experienced better mpg,either with the low-rolling-resistance of the tires,nor the reduced inertia of the lighter alloy wheels.The tires did have excellent wet and dry traction,not a bad reason to have them,but never delivered on the mpg promise.So all I can say to you is that the experiment didn't work for me.As to the wheel-covers,I did a post installment on Wheels/tires/wheel-covers.It may have some data for you to think about as to what you might expect from a set "of MOONS".Hope it helps,Phil.

[donee]

Hi D.D.,

Here is a link to the post on Prius Chat about the trim ring modification. Remember, on a standard car you may need to hipermile with verve to keep those brake temps down. No problem on a Prius, as it does most of its braking by the motors.

http://priuschat.com/forums/prius-mo...rim-rings.html

[donee]

[ebacherville]

Originally Posted by ttoyoda

[I]
I suspect the biggest problem is that in real life, a car is moving on a stationary road surface thru stationary air. All the wind tunnel models I know of a car have the "road" not moving, AND the car not moving, which is different than what really goes on. So the airflow under the car is different in the wind tunnel vs on the road.
To make that less confusing: In real life, the air does not move relative to the road. In the wind tunnel, it does.

When you model aircraft, the "road not moving" problem does not exist.

so what your saying is I need to build a big treadmill in my wind tunnel... ill get right on that

[COMP]

Originally Posted by ebacherville

so what your saying is I need to build a big treadmill in my wind tunnel... ill get right on that

and be quick about it ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,