We just had our TT out for the first time in a very long time, and are looking forward to getting it out more frequently here in 2021, with a least 1 long trip planned for this summer, but hoping to get a few shorter (3-4 day weekends) trips in as well. But something came to mind recently, I recall seeing large wind deflectors on the tops of TV's years ago, some were just simple wings, others were more elaborate, like the large "spoilers" you might also see on top of the tractors of 18 wheelers. Almost all big rig tractors running line haul have some kind of wind deflector on top of the cab to direct air flow up and over/around the trailer. So I did some internet searching and found surprisingly little information on this. There appears to be 2 main brands of air deflectors for TV's, Aero Shield and Aero Plus. The Aero Shield folds flat when not in use, but seems to be intended for larger vehicles than my Escape. The Aero Plus is intended to be mounted onto the stock roof racks on many SUV's like my Escape.I did a search here on this forum expecting to find discussions on these, but didn't find anything. Just curious if anyone has any experience with these air deflectors, would like to hear it, positive or negative. I'm thinking they may cause a bit of wind noise, maybe cause aggressive wear on a roof rack not designed to carry that kind of force, and that maybe why I don't see a lot of information about them is because they don't work.

Anything you can do to reduce turbulence will give you better mileage, quieter in cab, less buffeting in crosswinds when meeting big rigs going by on the upwind side. The savings and effects IMHO are not worth it. Big cost, little gain. The effort to push a vehicle into the air is not as effective as reducing the vorticae behind the towed. Aircraft are pointy on the back,not the front. On semi trucks, over sleeper air foils are worthwhile because they are close to the van so turbulence between them there is an asset, not a detriment as air passes down the sides of the van then enters in greater velocity the vorticae behing the van reducing the 'suction' effect. Most semi truck trailers now have under frame spoilers to reduce drag. Some have spoilers on the rear doors to reduce the vortice behind the van. Dont see as many now like that as we used to. Big trucks with a million miles to go 1-5% small savings in fuel over equipment cost, is good sense. Is it worth it to you? You might get a amall increase in economy, less buffeting ifrom winds Doubtful if cost over savings and comfort would be worthwhile. OTR drivers experience on cost and effects is an opinion I want to read.

I found this wing on Craigslist for $75. I had it painted to match the lower trim on my Excursion. I don't know who made it, but it was probably from the late 70's or 80's? I gained .5 mpg. One long trip and it paid for itself! Plus you could feel the engine wasn't working as hard due to the air flowing up and over the trailer instead of hitting it. Also the bug line at the top of the trailer disappeared showing that it did indeed move the air up and over the trailer. But it has to be mounted as close as possible to the trailer. If you have a pickup and put it on the top of he cab, it won't work as well.

In most cases with a TT, the front of the trailer is too far behind the back of TV to gain much. Mostly you just increase the size of the first suction zone. If you look at the freight trucks only a couple feet gap, and much of that is covered with cab extenders. Better would be something mounted to trailer, and back of trailer is most important.

Semis are much different use case: - very consistent trailer and spacing to truck, so they can dial in the aerodynamics very closely. RVs use a wide variety of trucks and trailers with wildly different designs and geometry. Plus the spacing for travel trailers is usually much further back making wind dams less effective. - Trucks may travel 50-100k miles per year vs 1-5k for a typical RV, so they can justify much smaller improvements based on fuel savings.

I had one of those a few years ago and the only thing it did for sure was to reduce the bug spatter on front of the RV. If it saved any fuel or reduced the strain on the truck I couldn't tell it.

Air Flow Deflectors | Good Sam Community

IAMICHABOD
Explorer II
Apr 02, 2021
Speaking of airtabs, I have AIRTABS on my Class C.

They really help on a cross wind situation,no more sudden buffeting. It has stopped the sideways push when being passed or passing a large truck.

They are a vortex generator that produce a counter rotating air trail several feet behind the vehicle, This airflow alteration improves vehicle stability. As far a mileage it may helped some but the stability they provided is amazing.
marpel
Explorer
Apr 02, 2021
Just found them (and boy was I wrong on the name).

You can find them at airtab.com

Marv
marpel
Explorer
Apr 02, 2021
A few years back, I read up on a product that is affixed (with a double-sided adhesive tape like substance) to the back edge of each side of the trailer/fifth wheel (vertical strips placed right at the corner on each side). They are designed to break the airflow and reduce drag and the vortex that a trailer being pulled through air causes. It's been a few years so can't recall full details but they are named something like "sharks teeth" (could be way wrong on that). New product at the time, but do recall some positive reviews. Supposed to be better than traditional wind deflectors. Don't know if they are still around but google should be able to find them.

Marv
RHasse
Explorer
Apr 01, 2021
Thanks for the replies, I appreciate it. I welcome any other comments, positive or negative.
prichardson
Explorer
Apr 01, 2021
Some real world experience here. Short bed pickup with deflector on headache rack and TT with vertical front like Dodge Guy - gain of 1 MPG.
With the same truck and deflector towing a TT with more angled and rounded front the gain is minimal. Even 1 MPG may not be enough to offset the cost of a deflector if there is not enough mileage driven.
12th_Man_Fan
Explorer
Apr 01, 2021
I had one of those a few years ago and the only thing it did for sure was to reduce the bug spatter on front of the RV. If it saved any fuel or reduced the strain on the truck I couldn't tell it.
valhalla360
Navigator
Apr 01, 2021
Semis are much different use case:
- very consistent trailer and spacing to truck, so they can dial in the aerodynamics very closely. RVs use a wide variety of trucks and trailers with wildly different designs and geometry. Plus the spacing for travel trailers is usually much further back making wind dams less effective.
- Trucks may travel 50-100k miles per year vs 1-5k for a typical RV, so they can justify much smaller improvements based on fuel savings.
JRscooby
Explorer II
Apr 01, 2021
In most cases with a TT, the front of the trailer is too far behind the back of TV to gain much. Mostly you just increase the size of the first suction zone. If you look at the freight trucks only a couple feet gap, and much of that is covered with cab extenders. Better would be something mounted to trailer, and back of trailer is most important.
dodge_guy
Explorer II
Apr 01, 2021
I found this wing on Craigslist for $75. I had it painted to match the lower trim on my Excursion. I don't know who made it, but it was probably from the late 70's or 80's? I gained .5 mpg. One long trip and it paid for itself! Plus you could feel the engine wasn't working as hard due to the air flowing up and over the trailer instead of hitting it. Also the bug line at the top of the trailer disappeared showing that it did indeed move the air up and over the trailer. But it has to be mounted as close as possible to the trailer. If you have a pickup and put it on the top of he cab, it won't work as well.
SDcampowneroper
Explorer
Apr 01, 2021
Anything you can do to reduce turbulence will give you better mileage, quieter in cab, less buffeting in crosswinds when meeting big rigs going by on the upwind side.
The savings and effects IMHO are not worth it. Big cost, little gain. The effort to push a vehicle into the air is not as effective as reducing the vorticae behind the towed.
Aircraft are pointy on the back,not the front.
On semi trucks, over sleeper air foils are worthwhile because they are close to the van so turbulence between them there is an asset, not a detriment as air passes down the sides of the van then enters in greater velocity the vorticae behing the van reducing the 'suction' effect. Most semi truck trailers now have under frame spoilers to reduce drag. Some have spoilers on the rear doors to reduce the vortice behind the van. Dont see as many now like that as we used to.
Big trucks with a million miles to go 1-5% small savings in fuel over equipment cost, is good sense.
Is it worth it to you?
You might get a amall increase in economy, less buffeting ifrom winds Doubtful if cost over savings and comfort would be worthwhile.
OTR drivers experience on cost and effects is an opinion I want to read.

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