Air deflector for truck and trailer

Thanks all. Think I'll save my money for fuel instead of spending it on this.
Appreciate all the responses!

christopherglenn wrote:
For them to be of any benefit two things must happen.
First, the deflector must be VERY close to the trailer, as in inches count - pull a TT and put the deflector on the cab roof and at best you move the bug line up. Mont it on the rear of a pickup shell, or suv and that is different story.
Second, the aerodynamics the front of the trailer must truly suck. A rounded front won't net anywhere the improvement as a flat wall. Dodge_guy has about the best setup for a deflector, 3-4 feet gap to a flat wall.

Yes. I always forget to mention that my TT has a pretty flat front and is 11.5 feet tall! our old 05 Cherokee had a laid back front and was 10.5 feet tall, I don`t think you would see as much an improvement with those style trailers.

For them to be of any benefit two things must happen.
First, the deflector must be VERY close to the trailer, as in inches count - pull a TT and put the deflector on the cab roof and at best you move the bug line up. Mont it on the rear of a pickup shell, or suv and that is different story.
Second, the aerodynamics the front of the trailer must truly suck. A rounded front won't net anywhere the improvement as a flat wall. Dodge_guy has about the best setup for a deflector, 3-4 feet gap to a flat wall.

On a pick up truck with a TT it will not work well. there is too much of a distance from the cab (where the deflector mounts) to the front of the TT. a fifth wheel would be a better trailer as the front of that is very close to the cab. I have a deflector on my Excursion. it is mounted at the very rear of the X. for me it was a noticeable improvement! I gained about .6 mpg towing. you can feel the it working because the X isn`t working as hard to move the trailer through the air. I can now stay in O/D a good percentage of the time. and judging by the bug line on my trailer (the very top 6") is all the bug splatter I get. I found it for $75 on CL. the deflector paid for itself on our trip to Myrtle Beach.

Here is my deflector.

Defectors are indicated for being able to work. The hypothetical side of things. Trouble is finding valid confirmation

AirTabs or Vorblades are said to actually work for better rearward visibility in rain. And keep trailer rear a little more steady. That's a win in my book.

But there is too much "noise" in the steering of pickup trucks, and too much ground clearance with both trucks and conventional travel trailers to register actual mpg gains. If the better handling/visibility is worthwhile, then they may worth the experiment.

A VPP hitch offers safer towing, and the side benefit is reduced number of steering corrections which translates to better FE.

Frankly, FE is bettered by trailer design and a turbodiesel TV drivetrain. A clean sheet of paper is how to maximize FE. From the beginning.

A trailer axle alignment and "perfect" hitch set up is worth quite a bit. Bearing and brake preset. Eliminate slop in TV steering. All things that should be done anyway. That done, some control over travel stops and in maximizing use of cruise control are the other end of things for combined vehicle travel.

For a more serious attempt at lowering travel fuel costs, control over vehicle costs in the day to day is key. I improved my city mpg by 20% on a dare for over 1000-miles. Extrapolated over a year it would COMPLETELY cover the towing fuel cost for 5000-miles.

Fun discussion with animation........RV.NET 2009

Conclusion:
Fun discussion with some animation :B

Personally........

Airfoils on trucks pulling trailers isn't cost beneficial.
MPG increase....minimal at best.
One benefit.....bug line moved higher

Issue is airfoil is just not close enough to front of trailer to be truly effective

Tractor/trailers (Semis) benefit cause deflector is directly in front of trailer, cab/deflector at same height/higher than trailer therefore air goes OVER front of trailer
And they drive 100000's miles every year

Carrera man wrote:
kaydeejay
Have you used one of these?

No I have not, but I HAVE worked in aerodynamics.
There is nothing out there that will give you a 20-25% improvement in gas mileage (assumes a typical 250-300 miles per tank).

I have been talking to folks at airtab, and they are going to send me info on the us distributor. Look for my post on this from about a week ago. Has anyone used--results.

I could see where it would work on a fifth wheel but I think there would be too much space for air to get sucked back down with a trailer.. Just my opinion.

keedeejay
Have you used one of these?