Anyone familiar with these things?

[TL-Super]

http://www.airtab.com/Images/photogallery/gallery1.htm

I would not put them on my car but I think anyone with a RV (or similar boxy vehicle) or hauling a trailer could see some significant benefits for high speed stability , and likely improved mileage. The reviews/testimonials are very positive and the product makes perfect sense. IMO anyways.


Just noticed there is a thread on this already.

[Gary Palmer]

Their have been some things, like this that have been tried. I have a 89 Honda Wagon and I have been thinking about trying something of this nature, but I hadn't figured out how to shape them. In principal, they should cause mini swirl in the air, so that it leaves the edges in a less turbulent/drag inducing manner, than theoretically occurs otherwise.

[n0rt0npr0]

I used them on my stolen chevy. You can see very vividly during misty rain the swirls they are producing. But the car was OBDI, and without scangauge I could not quantify any significant FE change.

[GasSavers_SD26]

Planning to get some for my enclosed trailer before spring when I start traveling. I'm looking for some real world results too. If it aids in stability, I'll enjoy that too.

[gto78]

I'd love to see them at work in a real wind tunnel. At college I saw a lot of wind tunnel test footage of objects shaped like the tractor trailers and how violent the air moves all around behind the trailer at highway speeds. I always wondered why they don't make a fin that extends the back of the trailer another couple feet and shape it like a tail. That will smoothly pull all the air from both sides together into the middle and leave a calm higher pressure air behind the vehicle.

Those VG's will definitely help, it's not the best solution but a start anyways.

[n0rt0npr0]

You always wondered?

It's purely because "big oil" has a diesel use quota they HAVE to meet to make the investment class happy. The ones that want efficiency, trust, are not the ones that can actually win the war and make efficiency happen. Nope, trust that there is a system, and efficiency does not have any place within it.

Originally Posted by gto78

I'd love to see them at work in a real wind tunnel. At college I saw a lot of wind tunnel test footage of objects shaped like the tractor trailers and how violent the air moves all around behind the trailer at highway speeds. I always wondered why they don't make a fin that extends the back of the trailer another couple feet and shape it like a tail. That will smoothly pull all the air from both sides together into the middle and leave a calm higher pressure air behind the vehicle.

Those VG's will definitely help, it's not the best solution but a start anyways.

[GasSavers_SD26]

Oh, yeah, there's a conspiracy....

All the proper data from it shows there might be a little reduction in drag available. Not a whole bunch. Aircaps have been available for years and years and years on the retail side of trailers, and they perform some of the duties that some of the aero studies have shown can be improved, but when I sold enclosed trailers, we sold none. People that I've known that had aircaps on enclosed trailers did not feel that they dramatically improved their mileage or handling. Similarly, individuals with V-nose trailers generally didn't have better mileage either. There were some improvements, but sometimes the extra tongue weight made things worse.

For $200, a bunch of Airtabs will be an interesting experiement, but, again based on the data that is available, it might be very hard for me to even quantify any betterment of my MPG.

Honestly, trailers would probably be redesigned, but the cost to those that would buy them would be more expensive than the current production items, and I could see where repairs to regular damage during use would be problematic.

As it is, I have never seen Airtabs in the truck stops that I've been in. Maybe some of the bigger ones have them, I'm not sure, but I have also never actually seen them on the road.

[usedgeo]

Did you notice the mileage claimed for that Dodge diesel dually? These claims are also under bug deflection on the Airtab home page. The numbers are hard to believe but they had been working on it for 16000 miles.

"We've increased our fuel mileage by about 9mpg on a full load, from 11-12 MPG to 20-21 mpg. We pull fast, heavy and long most of the time. With the Airtabs as installed, wind noise is reduced and the trailer stability is phenomenal. Evidence the Airtabs are working is most noted in rainy weather, in cross winds and meeting larger semi-trailers on two lane highways. The unloaded truck will get 25 mpg but with Airtabs fitted as per our pictures, we are getting 32-34 mpg.
The Airtabs on the top rear of the cab eliminate 80% of the bugs on the front of the trailer. If you watch the bugs, they tell you where the air is going.
The Airtabs on the hood of the truck keeps the windshield cleaner and reduces wind noise with the windows open."

Originally Posted by TL-Super

http://www.airtab.com/Images/photogallery/gallery1.htm

I would not put them on my car but I think anyone with a RV (or similar boxy vehicle) or hauling a trailer could see some significant benefits for high speed stability , and likely improved mileage. The reviews/testimonials are very positive and the product makes perfect sense. IMO anyways.


Just noticed there is a thread on this already.

[GasSavers_RoadWarrior]

Basic aerodynamics on these is they use the effect of high angle of attack delta wing swirl to create small vortices that aid vortex shedding. So if you want to find out how to design your own, research delta wing swirl.