Triangular protrusions

[Steve_382]

For a while they were putting them on the back of semi trailers to reduce the effects of side wind pushing the trailers around I think. Not sure it really worked or we would see more of them.

[mechmike10]

They are called Airtabs; I installed a set on our 2016 Sprinter Sportsmobile (3500, medium height, extended length). I can't see any mileage difference, but they do help a lot in cross winds (not a miracle, but definitely noticeable) and seem to keep the back end cleaner. I'd absoutely do it again.

[Spartan]

This is our van. They are air tabs. We have had these on our van for about six years and have had our van for 9 years. They do three things. 1- they do a very good job of keeping the back of the van clean. Much less dirt and dust on the back. 2- lessens the buffeting of the van when a big truck passes you on the highway. 3- the air tabs have increased our our highway MPG by 5%.

[wanderers]

I put some of these air tabs on my van after being told by another fellow that they substantially improved his mpg but I got negligible, if any improvement but at least they don't seem to hurt mileage. They do seem to help keep the back end cleaner, but only if you're travelling fast enough for the vortex to have an effect. Going more slowly on a dusty road it still gets quite dirty. My wife is convinced they help in crosswinds and when passing big trucks. They don't look that bad and I would probably have to have it repainted if I tried to remove them so they're on there for good now but I don't think I would do it again. They are a conversation starter though.
They're barely noticeable in this photo.
______________
Roger

[86Scotty]

Originally Posted by boywonder

The tail flaps on the semi trailers are there to do exactly the opposite of these things....when deployed they are supposed to keep the boundary layer air flow down the sides of the trailer laminar when it reaches the back of the trailer....reducing the "wake" behind the trailer....just like those long tear-dropped shaped helmets the road bike velodrome guys wear.

Yep, but those are mostly on the way out because the dock surrounds (big black insulated cushions around loading dock doors) are tearing them up. And the drivers tear them up. Companies are starting to figure it out.

OK, howbout a rant?

Commercial trucks have all sorts of this crap on them. By commercial trucks I mean the big companies (Swift, Schneider, JBHunt, Nussbaum). They buy the newest trucks/trailers and put all of this silly crap on them like air deflectors, moon cap type wheel covers, trailer tails, trailer fairings, etc. etc. Then they hire guys who couldn't give 2 shits about any of it and can't drive and truly don't care anything about the appearance or condition of the truck. These lousy drivers then promptly rip half of that stuff off and it never gets replaced. They biggest one you'll see is half the front bumpers ripped off of newer Freightliner Cascadias with the super low, craptastic plastic bumpers. Then with all of this stuff half ripped off, especially the front bumpers and tractor fairings, any minimal mpg gain or overall company fuel savings they might have achieved is negated by the fact that you've got trucks rolling around with no bumpers, pieces of bodywork flapping in the wind and creating drag, etc. It's the most bassackwards business model I've ever seen. If you travel on the highway much start looking and you'll see what I mean.

Sorry, that is all. No airtabs or any of that other crap for me. Saving fuel is simple and proven time and time again. Drive slower. I don't personally but it's a price I know I'm paying and I'm fine with it.

[gahamby]

As aerodynamic as my catamaran might be on the water, it's a huge frontal area on the trailer. I was just wondering if something on this line would help the airflow around the boat.

[JWA]

Originally Posted by 86Scotty

OK, howbout a rant?

Commercial trucks have all sorts of this crap on them. By commercial trucks I.......

I feel your rant and raise you one?

I work on and around the tractor-trailer rigs almost exclusively, installing USA made windshields in fact. Some of the driver-caused body damage runs from mild to half the stuff is missing. Mostly as long as a truck meets DOT and/or local PUCO requirements they're only repaired when time permits---typically a truck has to be sidelined before such repairs are performed---they don't make money sitting still so its "on the road again.........."

One day when I think of it I'll post photos from my local FedEx Ground trailer repair facility---some of those images will just scare the average partially observant member. I see them regularly and wonder HTH they did THAT?

Every truck outfit known has the same "driver's wanted" sign somewhere and the turnover in that trade is crazy. So much of the driver's schools are Federally funded in part or full so the influx of almost zero experience driver's unleashed on the unsuspecting world is very scary too.

Regarding aerodynamics improvement one of the big truck manufacturers wind tunnel tested the normally configured vehicles and found eliminating the rather huge exterior rear view mirrors would add significantly the MPG's. Since most are tickled to death getting something close to 8 MPG and driving in excess of 200K miles a year its easy to see the benefit of decreasing fuel consumption.

To date DOT won't allow complete removal of the exterior mirrors in favor of RV cameras and inside cab monitor screens. I'm sure the concern is driving blind if full electronic system were to fail which is a very possible scenario.

Anyway-------