Air Tabs

[ecomodded]

It is the wings shape that generates lift not the VG's.
As the video demonstrates the VG's keep the air attached to the wing.
less throttle is needed for the same speed.
A proven flow enhancer.
It is a airflow enhancer on the plane as it is on the Lancer Evolution.
The obvious place to mount them on a car is before the air detaches off the rear roof, to cause the air to leave in a determined straight flow,less flutter from the air detaching off the car.

[skyking]

A wing in free air does not exhibit the same properties as a car. That was the entire point of my post. I hope you have success with the air tabs, really.
My background is 25 years of aviation, including building experimental aircraft, flying highly modified STOL aircraft with tabs and drooped cuff leading edges, dragging huge banners through the skies over Seattle and Portland.
I just wanted to point out that the way the air moves about a wing will not represent how a tab will improve flow on a car. I look forward to any tuft testing you can do.

[ecomodded]

I have seen the tuft testing videos on youtube, People are video taping either attached flow or lack of flow over the rear glass with the vortex generators.
I do see your point of the different characteristics between a wing and a car. The wing needs lift to fly, the car needs lift to fly but its not good in the cars case ! obviously, So the place to use them on a car without generating lift is near the rear where there is no space to generate lift but space to direct airflow,which the VG's do. But alas, if the effect will have any outcome on fuel mileage is undetermined,i assume it would be minuscule at best. I do believe/ buy that they will effect or enhance the flow over a spoiler behind them.

[Sven7]

The wing is different not because it generates lift- road cars do that too- but because it is not in the ground effect as all cars are.

Sure, vortexes can put pressure on a spoiler but on Ecomodder we're not interested in racing.

[ecomodded]

Harsh, but I would say even 1/10 of a gallon gained over 2 tanks of gas would be considered a ecomod. To strike it off the list without fully testing and proven the abilities or lack of is not what a Ecomodder should do.

[jakobnev]

If the VG's work like in the video they will certainly pull the air down the back of your car, but if your car is shaped such that air leaving it's rear will have large downward and forward movement, it will not reduce drag. (See this thread.) The VG's caused the flow to be attached down the rear window but did not reduce drag until an extended spoiler was attached at the bottom of it.

[ecomodded]

That was a good read jakobnev.
I noticed in the VG video that the gas mileage was higher by about 1 more mpg until the end of VG part 2 when for some reason the speedometer increases to nearly 50 mph and the mpg decreases to 49.2, it was hanging at 51.9 earlier in the test.
I think the naysayers will not see the facts because they do not coincide with their preconception/doubt.
A great mod for people who like to think outside of the box as it is a unconventional low cost experimental mod.

[ksa8907]

If the big factors acting on the shape of a vehicle is frontal area and the low pressure zone at the rear, anything you do that will minimize the low pressure zone while not increasing frontal area, or at least significantly, will reduce your Cd.

[ecomodded]

The problem for me,after thinking yet more on it, is that on my New Beetle I put a little back glass spoiler to divert the air flow off and away from my rear glass. It is well know by VW that my car develops lift caused by suction over the rear glass. My spoiler is there to deflect the air away from the glass. So my problem is now will VG's force the flow down onto the glass or will it allow the flow to go off the spoiler in a aerodynamic curve toward the ground and traffic behind me. I think i am going to need to smoke test it , my deducing cannot work that problem out.

[skyking]

That's a tough one to crack. One of the new guys has some very good modeling software, maybe that could help out.