Wind Deflectors?

[VickSupra]

New to forum - did a search for info on potential effectiveness of air/wind deflectors.
I know several previous threads and this one indicate that they are not effective.  However, I noticed that some of these comments referred to pulling behind a pickup, and attendant issues with airflow over the bed.
We pull a 28 ft TT behind a Nissan Armada (SUV), after having driven a 32 ft Class C for years (we downsized!).
As an engineer, it certainly seems to me that most any reasonable "spoiler" or wing, properly adjusted, should help in reducing drag on the trailer (drag is, by the way, a function of the square of velocity).  Obviously, I am interested in actual test results (not anecdotes from manufacturers or distributors).  Has anyone found such results?
Also, I would like to find out if they can also improve handling (sway, etc) by reducing the drag forces?

My current related experience is with the downforce supplied by the wing on my car while road racing.  Similar principle, different application and desired results!

Any test results found?

Thanks.

 

[Gary RV_Wizard]

There is no doubt that a wind deflector could help, but it has to be designed (tuned) to the specific air flow of the rig to have much  effect. If you have access to a wind tunnel, you could do this. If you think you can install a generic deflector and eyeball an angle that will help, well then, lot's of luck.
The only independent data I have seen (and don't recall where it was) consisted of measured fuel economy with and without a wing/deflector and was performed by someone like yourself.  As I recall, the results were very modest and inconsistent, apparently depending on the angle of wind attack or some other external condition.

Here is one report that is somewhere between anecdotal and science. It is with a fifth wheel, but maybe it will help.

If you Google some keywords like RV TOWING DEFLECTOR and similar stuff you will find some info, but very little of scientific or engineering merit.

 

[WILDinTHEwoods]

A few things when towing the 2 ton trailer behind the 6 cylinder SUV that I learned from my experiences. 

1.  You won't be able to see down the sides of the camper without sideview mirror extenders.  Get the ones that are specific to your truck, they stay in place.  The one size fits all ones move everytime a semi comes from the other way (2 lane traffic).

2.  Get an E-qual-izer sway bar equalizer system.  They are everything they say they are.

3.  The transmission is going to be working very hard for you.  Without a transmission oil cooler I don't see that truck making it to next year without spending alot of money.

4.  The engine is also going to be working alot harder too.  Think of it like driving up a steep hill against 60 mph winds.  That's what it is going to feel like on the flats.  If you keep your speed below about 58 mph the transmission computer will keep the transmission in overdrive.  Any faster than that the transmission will be running in 3rd gear and down shifting into 2nd on the hills.

That in-line 6 is an excellent engine.  Good torque and very strong.  Be sure that ALL of the drive line fluids are fresh.  Engine, transmission, differentials, transfer-case, and the coolant.  New spark plugs and air filter.

OH YA!  One more thing...

5.  The brake controller.  You're going to have to adjust it a little when off and on the highway.  The weight ratio between the camper and the Jeep are close enough that the brake controller is going to have to be set a little higher on the highway than around town.  If you forget to turn it down in town the trailer will tell you.  When you press on the brakes it will feel like someone is grabbing you by the scruff of your neck and puling you back.  I know this sounds weird, but you will think of me when it happens and it will make sense.  If you forget to turn it back up when on the highway it is going to take a lot longer distance to slow down or stop.

 

[h2guy]

I have to believe that with the SUV piercing the wind, curved front end of the Airstream not that much higher than the SUV, its a wasted effort to add more weight and bulk to your SUV.

YMMV however.

 

[NCHornet]

[size=12pt]I have read real life results from many forums and not one claim these things do any good except to lighten the wallet. The biggest problem is most wings are between 4-5 ft and your trailer is 8ft wide, don't have to be a scientist to see the problem here.[/size]