Would air tabs help on my red brick(08 jeep liberty)

[KrautBurner]

Originally Posted by Frank Lee

You want this Jeep to suddenly become aerodynamic AFTER you buy it?

wow,

you've always been helpful

[Xist]

Congratulations, Kraut, you have the distinction of being the only Ecomodder I know to both bring a six year-old thread back from the dead and start a new thread on a discussion you could have found through searching.

Yes, I understand you did not know the name, and that sure can make searching difficult, but not impossible. Had you looked for "stick-on aero thingies" you could have found http://ecomodder.com/forum/showthrea...ils-23114.html.

You also could have sent an active user a private message.

[mcrews]

Originally Posted by Frank Lee

You want this Jeep to suddenly become aerodynamic AFTER you buy it?

actually, (ignoring the sarcasm) frank lee makes a good point.

You claim to have already done work on a couple of cars...


how could you possibly think that 'tabs on a red brick' would give you any truly measurable about of inproved mpg?

you would need a COMPREHENSIVE approach to get any possible gain.

[Natalya]

This thread is really old mcrews.

[mcrews]

Originally Posted by Natalya

This thread is really old mcrews.

Stalking much?

[Frank Lee]

IIRC There was a lot of stupid discussion going on at that time where many thought it would be great if, say, they put a pickup box on a Corvette and put Corvette running gear under a pickup. If ya want an aerodynamic vehicle, buy one that at least has a fighting chance. No, something that looks like the broad side of a barn ain't it.

[Poodwaddle]

You can make your own (for testing purposes) with a bit of thin cardboard or plastic and masking tape...but it won't (probably) do much good on a Jeep Liberty. Vortex generators cause the air to spin and hug a sharper curve than smooth airflow can. However on a Liberty there is very little curve to hug, it simply chops off at the back. You might see half a MPG dif.

If you have ever seen air spinning off the end of an airplane wing you get the concept of tabs. Tabs are tiny airplane wing tips. By angling the tabs slightly, you create higher pressure on the forward side and lower on the opposite. Thus the air will spill over the edge and cause a spin. Of course one could buy tabs that have been tested to maximize the efficiency of the effect, but even home-made tabs set at about the right angle will have enough effect for testing purposes...without costing hundreds of $. If you read the material about mounting the tabs you will probably glean enough info to figure out how and where to mount them. You might even plagiarize the general shape, though the shape of most are designed for attractiveness, not for efficiency. A flat/square wing creates the best vortex, but a sculpted sharp fin shape sells better. They are also designed for safety. A sharp wing edge is best, but the manufactures don't want to be sued...go figure. Tabs are placed in opposite angles, one left, next one right. This, I think, helps the vortex to carry far behind the vehicle without colliding with it's neighbor. Placing tabs too close will probably still cause interference.

The AirTabs brand is a special V design that builds two tabs into one unit... so don't copy them. Just make simple wings.

This is something that someone here could/should test. What is the best home-made tab shapes and angles. It would have to be someone with a sloped back window and someone who has regular enough commutes to get accurate results. I say "someone" because I don't have a regular commute and I am stuck in a city with VERY slow traffic.

Flat back vehicles like trailers and RVs do benefit from one other feature of vortex generators. They cause a reduced wake which somehow chops up the knock around effects of side wind gusts and passing trucks. I haven't read the science of it, but my theory is that when an RV is knocked around on the road by a passing truck it is due to the wind's effect on the RVs following wake, not so much the air hitting the RV's side. When the wake is knocked to one side it causes the RV to be pulled in that direction...and we all know the power of the following wake. I think that air tabs either block the wind a bit, or break up it's pull on the vehicle.

Incidentally, the divots in a golf ball cause the same effect. The air passing over the back of the ball can hug the ball to a greater angle. I think you should try tabs before drilling divots in your car though.

[freebeard]

Originally Posted by mcrews

Stalking much?

As for myself, I'm here because there is a dearth of new threads.

Poodwaddle -- That's the best thing to do with a zombie thread feed it braaiiins.

This is something that someone here could/should test. What is the best home-made tab shapes and angles. It would have to be someone with a sloped back window and someone who has regular enough commutes to get accurate results.

Go all Mythbusters on it. Commuting may not be the best test environment. I like the idea of a long tow cable with a streamlined tow vehicle and a 'vehicle in tow' sign in the middle so people don't cut lanes into it. Then with a simple spring scale and a dashcam you could get data independent of the drivetrain completely.

Also tuft testing and titrating gas from a graduated cylinder.