Side Mirrors...

[M_a_t_t]

Originally Posted by freebeard

F*=MA
*there will be a trig fuction for angle of attack. ...absent a linkage to reverse the force across the vertical axis.

Adjusting the spacing of the mirrors accounts for the angle. Not sure what you are trying to say with the second half.

[Phase]

I mean I’m going to try and make an aero cover that’s the same shape as the OEM mirrors, and then put that over the little 3 inch tab. I’m currently trying to figure out how I’d mount that little sucker though…

[freebeard]

That picture [which I apparently hallucinated] had the long edge of the blind spot mirror against the A-pillar, with a cover shaped like a fat louver.

[aerohead]

Originally Posted by Phase

I was thinking of replacing my big side mirrors with little tiny 3 inch side mirrors that are usually just use as wide blind spot mirrors. then id probably fit a another mirror inside the actual car for added safety

by making my mirrors 1/4th the size that they were, that should really help with drag right?

do laws state that side mirrors need to be a certain size? or that you just only need a mirror and nothing specific?

There may come a time when the only difference between a collision, or worse, will be instant, visual situational awareness.
The temptation of low-drag has the capability to blind us into missing the premise of some OEM equipment design, and the human factors research that went into the final product.
If nothing else, you might just look at the mirrors on the lowest drag extant production vehicles, and see if you can identify associated trends between their designs, depending on mounting strategy.
Fair market price for mirror wind tunnel testing and validation is $4,000/hour.
Let Tesla, Porsche, Jaguar, Chevy VOLT-II, etc. show you their 'solutions', on their nickel.

[Phase]

Originally Posted by aerohead

There may come a time when the only difference between a collision, or worse, will be instant, visual situational awareness.
The temptation of low-drag has the capability to blind us into missing the premise of some OEM equipment design, and the human factors research that went into the final product.
If nothing else, you might just look at the mirrors on the lowest drag extant production vehicles, and see if you can identify associated trends between their designs, depending on mounting strategy.
Fair market price for mirror wind tunnel testing and validation is $4,000/hour.
Let Tesla, Porsche, Jaguar, Chevy VOLT-II, etc. show you their 'solutions', on their nickel.

I’m essentially going to have 5 mirrors. If anything, my visibility should be even better

Two blind spot mirror tabs on outside of car, 2 regular depth square mirrors inside the windows, and then a curved ultra wide rear view mirror hanging

[Phase]

Also random question for the super aero math people, most of the tests that mention side mirrors being about 3 percent of drag, give or take, seem to be tests done at the classic 55mph. So I’d that a static or fluid/compounded percent? Does the 3 percent effect Increase the faster you go?

Obviously mirrors have barely any affect at 30mph in the city. And then tests around 55mph show a measurable drag increase. So would drag multiple even more when you’re going 80-90 mph and you see even more benefit of removing the mirrors? Or would it still stay at that 3 percent they claim

Sorry for such a noob or ignorant question. I’m just trying to soak in all of the knowledge I can!

[aerohead]

Originally Posted by Phase

Also random question for the super aero math people, most of the tests that mention side mirrors being about 3 percent of drag, give or take, seem to be tests done at the classic 55mph. So I’d that a static or fluid/compounded percent? Does the 3 percent effect Increase the faster you go?

Obviously mirrors have barely any affect at 30mph in the city. And then tests around 55mph show a measurable drag increase. So would drag multiple even more when you’re going 80-90 mph and you see even more benefit of removing the mirrors? Or would it still stay at that 3 percent they claim

Sorry for such a noob or ignorant question. I’m just trying to soak in all of the knowledge I can!

Don't ever stop asking questions! The most stupid one would be the one never asked.
As you've asked it, I'm unsure that the specificity of it has been properly addressed.
Here's some points to ponder:
1) The mirrors are only a fraction of the frontal area of the car.
2) Their frontal area and interference drag is part of the car, although one might wonder if the vehicle's critical turbulent boundary layer would be achieved in advance of the mirrors ( if you treat the mirrors as 'satellites' which orbit in formation close to the host vehicle ).
3) The small size of the mirrors suggest that their own Cd will not become 'constant' until a higher velocity is achieved.
4) Which begs the question of whether or not the 'vehicle's' Cd would require the higher velocity to 'flatline ' its Cd.
5) Convention has it that, around 20-mph, the vehicles Cd is 'fixed.' Warts and all.
6) If we accept that, then whatever percent of the total drag we attribute them to, that percentage would remain a constant, until the vehicle reached transonic velocity, where the air began to compress, and shockwaves could begin to form on certain areas of the vehicle.
Is that cloudy enough for you?

[freebeard]

I'll side with J. Edgar and Vman455 on that, you'd have to test it.

Large scale vs small scale times Reynolds Number sort of thing.

[Phase]

Originally Posted by aerohead

Don't ever stop asking questions! The most stupid one would be the one never asked.
As you've asked it, I'm unsure that the specificity of it has been properly addressed.
Here's some points to ponder:
1) The mirrors are only a fraction of the frontal area of the car.
2) Their frontal area and interference drag is part of the car, although one might wonder if the vehicle's critical turbulent boundary layer would be achieved in advance of the mirrors ( if you treat the mirrors as 'satellites' which orbit in formation close to the host vehicle ).
3) The small size of the mirrors suggest that their own Cd will not become 'constant' until a higher velocity is achieved.
4) Which begs the question of whether or not the 'vehicle's' Cd would require the higher velocity to 'flatline ' its Cd.
5) Convention has it that, around 20-mph, the vehicles Cd is 'fixed.' Warts and all.
6) If we accept that, then whatever percent of the total drag we attribute them to, that percentage would remain a constant, until the vehicle reached transonic velocity, where the air began to compress, and shockwaves could begin to form on certain areas of the vehicle.
Is that cloudy enough for you?

thanks for that answer. any suggestions on how to mount the little side tabs? off the top of my head, i was thinking of getting a tiny block of wood thats a few inches long, drill a 10mm screw into it, and then just insert it into one of the 3 10mm hole slots from the former mirror, then just stick the 3m tape mirror onto that little wooden arm sticking out. maybe use some high grade gorilla glue combined with the 3m sticky thats included. then obviously build some type of aero shell around it

[aerohead]

Originally Posted by Phase

thanks for that answer. any suggestions on how to mount the little side tabs? off the top of my head, i was thinking of getting a tiny block of wood thats a few inches long, drill a 10mm screw into it, and then just insert it into one of the 3 10mm hole slots from the former mirror, then just stick the 3m tape mirror onto that little wooden arm sticking out. maybe use some high grade gorilla glue combined with the 3m sticky thats included. then obviously build some type of aero shell around it

You could certainly mock it up that way, just to see if you could live with the optics of it.
If you like the mockup, then translate that into a structural metal strut , for safety, and some means in which to 'gimble' the mirror for 'aiming.'
The strut could be streamlined after the fact. and some permanent fairing over the new optics.
Technically, the mirror needs to be tested in the exact location in which it will reside. It's the only place where the local flow will be whatever it's going to be.
As a first principle, the mirror fairings on the 1996, PORSCHE 911 GT1 race car, would be an example of a near-minimum drag form, according to Sighard Hoerner's drag tables. You must consider them in the context of their type of stalk, and mounting location on the Porsche.