Side mirror drag & effect on fuel economy - quantified

[Vekke]

I like the Vw Polo WRC mirrors a lot. In fact I am desinging similar setup to my A8 project.

I will use the same mirror panels as in the lupo project so the frontal area reduction is about 80% smaller frontal mirror area. I am trying to buy my own 3d printer so those will be available later this year if everything goes as planned.

[deejaaa]

we have our own 3D printer guy here. send a PM to get it earlier:
http://ecomodder.com/forum/showthrea...ter-30670.html

[getzfamily]

Just wondered if anyone has any info about the potential improvement if going a somewhat smaller mirror and then creating the ideal shape around that size? i.e. the body of the side mirror would end up significantly longer/larger but would the improvement in aero be more significant than the negative of larger body in air?

[freebeard]

I didn't review this thread but the 'ideal shape' has a tapering afterbody and that conflicts with being able to see into or out of the mirror.

Getting a small mirror as close to the driver's eye is probably the best you could do. These mount on the top center of the door window.


Vintage Peep Mirror | eBay

The 4" ones can have a visor (that is probably no help), a convex lens or built-in turn signal repeaters. They also come in 3". They do require a framed window, but my VW would need a slot cut in the weatherstrip channel, so none for me.

[aerohead]

Originally Posted by getzfamily

Just wondered if anyone has any info about the potential improvement if going a somewhat smaller mirror and then creating the ideal shape around that size? i.e. the body of the side mirror would end up significantly longer/larger but would the improvement in aero be more significant than the negative of larger body in air?

So far,we've got a number of considerations to think about and there's no generic recipes for low drag mirrors.
Drag will be affected by:
*location
*distance from body
*shape of housing
*shape of mounting stalk
*frontal area
*local velocity
*local flow pattern
*degree of mirror inset from 'end' of housing
-------------------------------------------------------------------------
Here you can see the difference in drag for a solid body of revolution with a prolate elliptical nose.The lowest drag bodies are rather 'long.'

[getzfamily]

Originally Posted by aerohead

So far,we've got a number of considerations to think about and there's no generic recipes for low drag mirrors.
Drag will be affected by:
*location
*distance from body
*shape of housing
*shape of mounting stalk
*frontal area
*local velocity
*local flow pattern
*degree of mirror inset from 'end' of housing
-------------------------------------------------------------------------
Here you can see the difference in drag for a solid body of revolution with a prolate elliptical nose.The lowest drag bodies are rather 'long.'

Hi Aero, was hoping you'd chime in. I was thinking more of moulding a shape similar to that of the ideal bodies discussed over at the aero thread for the entire car shape. So it would be a large side mirror in all aspects.
I've got some clay to form on one and see how a tuft test goes (Whether its accurate over such a short length and small area I don't know). Will upload pictures as I'm not sure I'm explaining it the best.

[mapleridge]

I bought a pair of manual oem mirrors for my 2001 civic lx. I want to cut them down to make oem fitting block of plates but want to integrate cameras and monitors on the inside. Anyone have any experience with running monitors and cameras for side view that are constantly on while driving?

[NeilBlanchard]

Yes, I drover for over 5 years with side video mirrors, in my 2005 Scion xA. The part of the thread on this is here:

http://ecomodder.com/forum/showthrea...tml#post105631

[Vekke]

On the audi A8 my printed mirrors worked well, but the glue did not hold during winter. SO those should be bolter through the door panel to sure they hold in shaking.

These new effiicient car models seem to start putting the mirrors again to door panel instead of a pillar corner and I believe the reason is lower drag coefficient. all the other new cars put the leg of the mirror as low as possible and thin as possible. So you would want your mirror to be as low as possible and leave the a pillar corner a gap for the air to flow nicely

I bougth to my touareg Opel corsa mirrors, which were really cheap about 30€ per piece online.
I am hoping to see a 0,015 drag drop in my touareg which has huge mirrors at the moment.

[freebeard]

You can get peep mirrors with turn signals repeaters.


http://i.ebayimg.com/images/i/351066...-1/s-l1000.jpg

They're much closer to the driver's eye, more peep/sq. in.