Do Air Tabs really work?

[palehorse89]

6 yr. old subject, no save your money and buy fuel..........Enjoy!!

[palehorse89]

And...... WELCOME TO irv-2!!!!

[Dutch Star Don]

Every time fuel goes up the air tab posts come out. Waste of time and money.

[Ray,IN]

Originally Posted by TomMiller

I have recently heard about a product called Air Tabs which are supposed to improve the handling of your RV on windy days and reduce the push effect of big trucks passing you? Has anyone installed this product that can offer some end user feedback?

Thx,

No they do nothing to improve fuel mileage. My SIL is maintenance manager for a nationwide trucking company. He said when they came out his company commissioned a wind-tunnel study (at the facilities of the INDY 500) of all available aftermarket products to improve fuel mileage. The air tabs did not affect fuel mileage. The only things that did were the "wings" that bolt on under a semi-trailer..

[VanDiemen23]

I think someone was feeding your SIL a line...

IMS has no wind tunnel facilities. At the time that air tabs came out, the chassis were made by Lola, Reynard, G-force, and Dallara - all of which used wind tunnel facilities in England and Italy which are too small for a semi. There are only a couple of tunnels in the US still operating that are big enough for a semi and those are $$$$$$.

There are other ways to skin the cat - Chip Ganassi used to lease one of the old highway tunnels in Pennsylvania and do coast-down testing. Basically you instrument the car, run it up to speed, punch in the clutch and coast down to another speed. Do that with several configurations and you start to get an idea of what's going on.

Then there's sub-scale testing and CFD.

I wouldn't be surprised if DOT or even the state of CA funded a sub-scale wind tunnel study at a university. That's frequently the way they do things and use the results to set policy and regulation. If there was such a study, and it found measurable improvement, I'm sure the manufacturer would have that quoted on his website....

The web site does quote a lot a relevant NASA work on the subject in general - but nothing specific regarding his product. There's one article written by a guy with a sprinter van who took his vehicle to a "local college" with a wind tunnel. Well, once again, I'd be suspicious of this claim, especially because to do it right you have to do a lot if instrumentation design and setup, and it's not something a couple of guys are going to knock out in an afternoon.

[SergioP]

https://vorblade.com/howitworks/flat...ck-bus-or-van/

I ran across these. Totally different design than Air Tabs. I would be interested for crosswind and general handling improvements than fuel economy. If they did improve mpg it would be a bonus.

[mr.tommy]

Originally Posted by Cbones

Reducing your speed by 1-2 mph will have more effect on your mpg than these air tabs will ever have.

This is the correct answer

If you want to reduce/eliminate the push effect of big trucks passing you just install a rear trac bar. It's a DIY install and makes a huge difference.
https://www.amazon.com/dp/B009WQQJHQ....1FUC3YMUOK6RD

[Ray,IN]

Originally Posted by VanDiemen23

I think someone was feeding your SIL a line...

IMS has no wind tunnel facilities. At the time that air tabs came out, the chassis were made by Lola, Reynard, G-force, and Dallara - all of which used wind tunnel facilities in England and Italy which are too small for a semi. There are only a couple of tunnels in the US still operating that are big enough for a semi and those are $$$$$$.

There are other ways to skin the cat - Chip Ganassi used to lease one of the old highway tunnels in Pennsylvania and do coast-down testing. Basically you instrument the car, run it up to speed, punch in the clutch and coast down to another speed. Do that with several configurations and you start to get an idea of what's going on.

Then there's sub-scale testing and CFD.

I wouldn't be surprised if DOT or even the state of CA funded a sub-scale wind tunnel study at a university. That's frequently the way they do things and use the results to set policy and regulation. If there was such a study, and it found measurable improvement, I'm sure the manufacturer would have that quoted on his website....

The web site does quote a lot a relevant NASA work on the subject in general - but nothing specific regarding his product. There's one article written by a guy with a sprinter van who took his vehicle to a "local college" with a wind tunnel. Well, once again, I'd be suspicious of this claim, especially because to do it right you have to do a lot if instrumentation design and setup, and it's not something a couple of guys are going to knock out in an afternoon.

You are right about size, they had a 1/8 scale model constructed to exact dimensions of a semi-tractor trailer for the wind tunnel testing.
No-one has ever produced any proof Air-Tabs actually increase fuel mileage.
That link proves their wind tunnel exists.

[Dodge Guy]

People told me an air deflector wouldn’t do anything for my Excursion and TT. Well not only did I gain .5 mpg! I also got rid of 90% of the bugs splattered on the front of the TT!

[VanDiemen23]

Originally Posted by Ray,IN

You are right about size, they had a 1/8 scale model constructed to exact dimensions of a semi-tractor trailer for the wind tunnel testing.
No-one has ever produced any proof Air-Tabs actually increase fuel mileage.
That link proves their wind tunnel exists.

I wasn't arguing that they work for fuel mileage, and in this thread and a couple of others, never have. I was making a point about full scale wind tunnel testing.

As you go that far sub-scale in wind tunnel testing it gets harder and harder to evaluate even smaller things like airtabs. The level of accuracy in the model, and even stuff like surface finish comes into play. That puts error into the measurements and soon error is bigger than the intended results.

Then, there's wind-tunnel vs real world. Wind tunnels are laminar flow. Airflow in traffic is not.

this is probably why you hear people talk more about stability benefits vs fuel mileage.

As I stated before - driving behind a semi in rain you can watch the vortexes shed from each side of the trailer and the wag that goes with it. You can also see this in the wake of some ships. Eliminate the big vortex and you'll get better stability.

[Elzaar]

Is that claim about your deflector true and where did you get the deflector?

This is an old thread, so trying not to spin it up again.

[SergioP]

Originally Posted by Dodge Guy

People told me an air deflector wouldn’t do anything for my Excursion and TT. Well not only did I gain .5 mpg! I also got rid of 90% of the bugs splattered on the front of the TT!

https://youtu.be/GmIiRrlM7Ng

At about 7:00 he talks about this very setup you have and they think your setup is the best of the three.

[Mudfrog]

Originally Posted by Dodge Guy

People told me an air deflector wouldn’t do anything for my Excursion and TT. Well not only did I gain .5 mpg! I also got rid of 90% of the bugs splattered on the front of the TT!

It makes sense that a wind deflector like the one you have mounted would make some difference. I have a small deflector on the hood of one of my Jeeps that really helps keep bug splatters off the windshield.

The product this thread is about is not the same. I doubt air tabs do much of anything except reduce the amount of cash a person has in their wallet.

[Elzaar]

Good video. Thanks for sharing it.