Vortex Generators / Hmmm Airtabs - Page 8 - Fuelly Forums

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Old 11-21-2006, 09:39 AM   #71
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I remember those glass-clearing deflectors on the back of one of my parents' station wagons when I was a kid.

I would say those would make aerodynamics worse, not better. They increased projected frontal area, and as they blast air down the rear window, they would increase pressure drag aft of the deflector and increase the size of the trailing wake.



VG's could also increase projected area, but the theory (as I understand it) of placing them at the trailing edge of a vehicle is the tight vortices they create are supposed to extend the effective aerodynamic length of the vehicle: since the vortices would be drawn inwards in the low pressure area, they supposedly create a "virtual" boat tail, and minimize trailing wake.
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Old 11-21-2006, 12:50 PM   #72
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I've been in touch with my Airtabs contact again.

I'll pass my test outline by him before I do the runs to make sure I don't find out after that I did something wrong (ie. placement/orientation).

He has already suggested testing in 2 separate configurations for a hatchback:

- tabs along the trailing edge of the roof only;
- tabs on the roof edge plus along the trailing edge of the sides
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Old 11-22-2006, 10:52 AM   #73
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I mounted mine along the trailing edge of the roof, without any on the sides. I still have a few extras that I have not installed. let me know how your A-B-A testing works out. I may install those later on.

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Old 11-22-2006, 12:14 PM   #74
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I'm not sure of the size of these but they are supposed to be a certain distance apart or else the vortices don't form properly. Putting them too close together will make the adjacent vortexes interfere with each other.

The problem with the rear high wing is that it produces drag where as a vortex generator does not (not much anyway).
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Old 11-22-2006, 12:57 PM   #75
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For standard Airtab size (I'm not even sure if there's more than one size), spacing = 4 inches on center (minimum).
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Old 11-22-2006, 01:46 PM   #76
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Ok the are 4" on centers and 3.25" wide so 3/8" between each so they are pretty close to each other. I would have thought they would be further apart to allow the vortex to be bigger.
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Old 11-29-2006, 08:30 AM   #77
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mine are mounted 4" to the centers

i also thought they would be mounted further apart than they were
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Old 11-29-2006, 01:37 PM   #78
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Quote:
Originally Posted by JanGeo
Ok the are 4" on centers and 3.25" wide so 3/8" between each so they are pretty close to each other. I would have thought they would be further apart to allow the vortex to be bigger.
There is / was a question 'way back when... "How many angels can dance on the head of a pin?" My standard answer : "Ball point or fountain?" LOL!
These tabs remind me of this scene.... But I DO appreciate the pic of the Gremlin! Wonderful! I couldn't get outta that ride soon enough! "Sicks" cylinder / automatic / power nothing / steering wheel like a Greyhound bus ... but it rode well with the large sway bars I put under it, front & rear...and the stiffer shocks I put in. Bench seats, no radio, just back & forth to work / stores. Deja Vu? In my "rear-vu" mirror I could see at last! No dirt, no rain beads! It worked for this! MPG gain? With a slip-n-slide automatic? Who even cared? I bought it off the lot (new) and I needed a ride, NoW!
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Old 12-12-2006, 10:57 AM   #79
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I'm thinking I may try to run 2006's last experiment this week
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Old 12-12-2006, 11:01 AM   #80
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I'm eagerly awaiting the results!
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I think if i could get that type of FE i would have no problem driving a dildo shaped car.
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