YO Capt!.......'air tabs' revisited

[Big_Dave]

I've seen this guy several times when I happen to stop in at the J in Peculiar MO (he seems to be there a lot or at least whenever I stop in). I managed to snap this pic as he was leaving the other morning.

I know you have your doubts about the 'air tabs' and their effectiveness.

Can ya find out who he is and talk to him and find out IF they do make a difference in his fuel mileage or not?

I didn't catch the entire hood of his truck, but the sleeper shows a bunch of them on it. He's got 'em all over the sides and the top front of his grill also. :wow:
http://img.photobucket.com/albums/v110/southernrain/airtabs.jpg

[Capt._Chaos]

I'm not sure if I'd get an honest answer (can you say "Placebo Effect"?).

Remember Paul Abelson? He tried them on his personal van, and all he said about them is it kept his back window clearer on rainy/snowy days. If he saw any sort of fuel mileage increase, he would have mentioned it.

[Preacher]

I've read studies on AirTabs and they can increase fuel mileage by approx. 1/2 mile per gallon. That's a potential savings of $3700 per year on 120,000 miles. Not bad considering they cost around $250 to put on your cab. If you run a dry van or reefer and put them on the trailer, you can expect even better mileage. The fact that Paul Ableson put them on his personal van and they kept his back window clean is a testimony to their effectiveness. They stop the swirl effect behind your cab (trailer too if you add them) creating a much more slippery aerodynamic effect.

[Capt._Chaos]

Preacher, not to sound confrontational or anything, but if there were any real benefits to using AirTabs, every major fleet would have them on their equipment to save on fuel costs.

Kinda like that Turbo 3000D Vada- I doubt it really works, or every fleet would have them on their trucks.

[joerockhead]

And you've tested these products....I didn't think so. :wow:

[Capt._Chaos]

And you've tested these products....I didn't think so. :wow:

Never said I have tested them. Just expresing my own skepticism, that's all.

[Preacher]

I do believe that they some fleets using the AirTabs. Contact AirTab for more info on fleets that are using them. I personally talked to an expediter that had them on their box and saw a marked improvement in fuel mileage.

[Mark-the-Spark]

I understand Jeff's skepticism, but I also think that they may provide a benefit, while further thinking that the people managing large fleets these days are not necessarily the brightest bulbs in the box (part of the compartmentalization of large companies and the resultant inter-departmental finger pointing).

Let's face it -- the CEO of many of these outfits probably wouldn't know which end of a truck ran over him :rofl:

Another problem is the testimonial -- many drivers that install these or other gadgets really don't have any kind of a true statistical basis to judge them better or not -- different weather conditions, different loads, different routes, different fuel -- too many variables for anything other than a true lab test to measure the difference.

The shape of the air tabs look correct, based on what I've seen on small airplanes that I used to fly and read of old aerodynamic theories (most aerodynamic theories are 'old'). The concept of parasitic wind drag at the rear of a square box (such as the end of a trailer) is also surely correct (some rear loading ocean ships had problems with this from a hydraulic (water) point of view). The concept of parasitic wind drag between the rear of a tractor and the front of a trailer seems to be correct, otherwise we would not see the fairings that we see on the rear of tractors today (and the conventional wisdom that more than 30" between the rear of the tractor and the front of the trailer is a killer to fuel mileage).

If I were to bet one way or the other, I would bet that they help. Why the large carriers have not latched onto them, I do not know.

I also do not know why the large carriers have not embraced things like Centramatics, Espar cab heaters, and Cats Eyes. All would seem to easily pay for themselves in the long term, and all but the cab heater are easily transferrable to replacement vehicles.

_____________________
Mark; shrugs

[Mark-the-Spark]

Dave, I slept at the Peculiar J last nite... small world :)

_____________
Mark; 29540

[HSLD]

#1. Aren't they mounted backwards????? Little end faces into the airstream.

#2. Aren't they meant to be mounted on the tail of the trailer? Or at least that what the manufacturer's recommendation for mounting?

v/r

HSLD

[Big_Dave]

#1. Aren't they mounted backwards????? Little end faces into the airstream.

#2. Aren't they meant to be mounted on the tail of the trailer? Or at least that what the manufacturer's recommendation for mounting?
1. I dunno. :wtf:

2. I seen a truck that was leased to Landstar the other day. He had them similarly located on the tractor and along the sides and top of the rear of the trailer. I didn't get a chance to talk to him on the radio to find out the scoop if they were worth the cost and what, if any, improvements in fuel mileage was.

[Mark-the-Spark]

#1. Aren't they mounted backwards????? Little end faces into the airstream.

#2. Aren't they meant to be mounted on the tail of the trailer? Or at least that what the manufacturer's recommendation for mounting?

1) No.

2. They can also be mounted on the tractor fairings, since there is some turbulence between the rear of the tractor and the front of the trailer. In this application the benefit is probably less.

You can find their website at www.airtab.com

[HSLD]

Guess the trailer I saw had 'em mounted backwards. :D

v/r

HSLD

[Paul Abelson]

Since my name has been mentioned in the posts, I might as well speak for myself.

I tried AirTabs because the theory made sense; good, solid aerodynamic principles. I did not cite fuel mileage because I did not have the ability to conduct a SAE/TMC test using approved methodology. Such tests cost about $25,000 plus for each set of test sequences.

I found that the rear window on the van was kept cleaner because the vortecies (vortexes?) took the airflow back and reduced turbulence right behind the van. This was obvious when driving in snow, when the airstream became visible. In any wet weather, I needed the rear wiper about 10% to no more than 20% of what I needed without the AirTabs.

In a tractor, the AirTabs should, in theory, attach the airstream to the trailer without allowing much turbulence behind the cab. Behind the trailer, they seem to provide a long, tapered airflow.

The Society of Automotive Engineers (SAE) created an Aerodynamics Working Group at last November's Commercial Vehicle Meeting. AirTabs was a participant. I believe they are applying to partcipate in some government funded testing. I'll report more as it develops.

The group tried to schedule a meeting at the upcoming TMC Annual Meeting, but there was no available time. We will meet later this year, tbd.


HSLD - Wide end faces into the airstream, collects the air and funnels it off the raised point somewhat like a cyclone. They are best mounted at the aft edges of tractors and trailers, across the sides and top.


Jeff - As we discussed, I'm still waiting to see SAE/TMC test results on the Turbo 3000D, or to at least find out what sound science theproduct is based on. I first asked at least 4 years ago. Surely by now, they've sold enough units to be able to afford verified, repeatable third-party objective testing. Also, I have not seen them involved with either SAE or TMC, the two technical societies serving the trucking industry.

[Paul Abelson]

There was a trailer areodynamics session at TMC. Discussions seemed to indicate a 1% to 3% mpg gain with airtabs just on the trailer. No one had definitave studies, and there are other devices being tested, individually and in combination with others.

Side skirts under trailers appear bery promising (4% to 6%) and difusers in front of trailers (2% or more) also appear effective.

The Working Group will likely meet before the SAE Commercial Vehicle (ComVec) meeting this fall. Gary Green of OOIDA is also involved.

[Mark-the-Spark]

Paul, thank you for the update :)

[Paul Abelson]

I apologize for the typos. I shal proooof reed better next time.