Low drag mirrors

[Idahotom]

Am I the only one to fold the side mirrors back? I'm talking middle of Wyoming, and into a 30 mph headwind. I was always in the right hand lane, (interstate) traffic was very light, like none. My neck still can turn, and I have a rear view mirror. As I neared a town, I'd flip them back out. Safe enough, probably not legal. I havn't done it since, just that long stretch with the headwind and it was getting real boring. Can't say I could see a difference on the scangauge, and I only did it for a couple hundred miles.

[MUSKOKA800]

I'd rather have full visibility than be obsessed over the drag, if any, they add.
I'd think the envelope that the front of the car creates going through the air at highway speeds extends out past the side mirrors. If it didn't, wouldn't the manufacturers see this in the wind tunnel and tune the mirror size/shape accordingly???

[Klink10]

Tune the size accordingly? You would think but then they can't even come up with a quality waterpump.

[Toyota_Yaris]

Originally Posted by Klink10

Tune the size accordingly? You would think but then they can't even come up with a quality waterpump.

hahahahaha x's 2

62k miles on mine and I just went through my first waterpump

[why?]

actually mirrors are tuned for visibility first, and drag is accepted in that area.

You can buy racing style mirrors if you'd like, they are much smaller. Garm has a set mounted on his yaris.

and so a few waterpumps aren't perfect. That stinks, but there are always a few stupid problems with cars. Thank God the Yaris is one of the best in this category.

[Idahotom]

After hearing about guys who remove the windshield wipers for less drag, folding back the mirrors seemed pretty minor. A one time deal for me, though I do like how they hold their adjustment through the folding process. Maybe the next time I'm driving through Wyoming I'll do it again!

During that leg of the drive, I saw a state trooper had pulled over a Prius, and I had to wonder for what, too fast, too slow??? Drafting semi's maybe?

[why?]

prius drivers are usually snobs who forget the rules apply to them as well.

[Midnight Drifter]

Originally Posted by why?

prius drivers are usually snobs who forget the rules apply to them as well.

Oh, please. When I was coming home from Georgia, one of the fastest cars I drafted before the VA border was a Prius with the Virginia plate SAVN GRN. She averaged 95 mph and had a Greenpeace sticker on the back of her car.

...yeah, that's totally what you're supposed to do in a Prius. Floor it the whole way home to save gas.

[derickveliz2]

I would like ti see some smaller rear view mirrors that not only have less drag but generate less "wind noise"

[cali yaris]

Prius bashing =

[cfeng]

i dont see how adjusting the mirrors will make a difference at normal driving speeds. sometimes drag is even beneficial. for example, the antennae, which seemingly produces unnecessary drag, helps to trip a turbulent boundary layer for higher efficiency and lower overall drag.

[Idahotom]

Originally Posted by cfeng

i dont see how adjusting the mirrors will make a difference at normal driving speeds. sometimes drag is even beneficial. for example, the antennae, which seemingly produces unnecessary drag, helps to trip a turbulent boundary layer for higher efficiency and lower overall drag.

What...you wind tunnel testing the Yaris with smoke streams or something?
The antenna is drag, though not much. As are the mirrors, less so when folded but who wants to drive around with no mirrors, besides me, one time!

[cfeng]

i use a water tunnel in my lab. i've been thinking about this. with a properly designed rear wing on the hatchback, it may be possible to increase fuel economy.



the top picture is similar to a stock yaris, air swirls in vortex patterns, which means that not only does the yaris need to propel itself forward, but spend considerable energy into moving air. with the correct rear wing, there could be less separation in flow at end and less movement in the air, similar to the bottom picture. i found this picture online, the second picture is misleading because it represents an ideal case with virtually no separation in flow.

the antennae will disturb how the eddies are shed, reducing wasteful swirling of air (reduce a little). similarly, if a wing is designed to reduce the size and number of eddies from forming by increasing turbulence at the rear of the car, the car will have less drag and overall better efficiency.

[Yaristeve]

Originally Posted by cfeng

i use a water tunnel in my lab. i've been thinking about this. with a properly designed rear wing on the hatchback, it may be possible to increase fuel economy.



the top picture is similar to a stock yaris, air swirls in vortex patterns, which means that not only does the yaris need to propel itself forward, but spend considerable energy into moving air. with the correct rear wing, there could be less separation in flow at end and less movement in the air, similar to the bottom picture. i found this picture online, the second picture is misleading because it represents an ideal case with virtually no separation in flow.

the antennae will disturb how the eddies are shed, reducing wasteful swirling of air (reduce a little). similarly, if a wing is designed to reduce the size and number of eddies from forming by increasing turbulence at the rear of the car, the car will have less drag and overall better efficiency.

Intersting drawings. What do you think (as in "do you think they work?") of those little "shark fin" vortex generators and Air Tabs? I was thinking of sticking on a row of the latter on the top of my hatch door but not on the sides as they recommend.

[cfeng]

Originally Posted by Yaristeve

What do you think (as in "do you think they work?") of those little "shark fin" vortex generators and Air Tabs? I was thinking of sticking on a row of the latter on the top of my hatch door but not on the sides as they recommend.

Its difficult to get something like this done right through trial and error. Unless if you have access to a full scale wind tunnel. I know that they are used on other cars already, I think one of the earlier evos had something similar.

The reason I was thinking about a wing is that it is larger and easier to test in the water tunnel at my lab. The job is the same, to trip turbulence that will be helpful in reducing drag. The equipment I use has lasers measuring the movement of small aluminum particles in water to visualize the flow on a computer. However, unless if the changes are drastic, this equipment probably wont accurately show the influence of tabs on a miniature yaris.

BTW, does anyone know where i can find a model yaris?

[derickveliz2]

What about the Sedan?

D.

[cfeng]

can't say for sure. it would seem that a sedan will have separation in the back as well, however it may not be as defined. since the wing might help reduce the effects of separation, i'm not sure how much benefit you have if the separation is already less than the hatchback. however, i dont have much experience on aerodynamics of cars, i work on fish.

[sickpuppy1]

Originally Posted by cfeng

dont have much experience on aerodynamics of cars, i work on fish.

So are you creating more hydrodynamic fish? LOL