Does anyone use an air foil? Are they worth the m - Montana Owners Club

osofine · 10-15-2007, 07:19 AM

I think I want an air foil for the roof of the truck to improve the drag and gas mileage. Has anyone had experience with one? I don't see them in any of the pix of trucks and monties. I am looking at one made by Icon technologies in Canada for about $369. It's plastic and can be painted to match the truck. We plan to drive a lot - especially this first year until we find where we would like to light for a while.

ols1932 · 10-15-2007, 07:25 AM

When we first started RVing 30 years ago the selling factor for the air foil was decreased drag and improved mpg. Of course, I bought one. When we traveled with and without it I kept track of mpg and found no noticeable difference. My cousin swore by his but I think he drove a lot faster than I do. We travel in the neighborhood of 56-58 mph and find that our mpg was the same with and without the air foil. Guess what? I threw it in the junk yard.

Orv

LonnieB · 10-15-2007, 07:25 AM

This is only my opinion, but with the streamlined design of the front cap on the Montana, I don't know that it would help anything.

I'm sure someone will be along with more info though.

On Edit - See, it happened before I got through typing.

bsmeaton · 10-15-2007, 07:38 AM

I think Lonnie is right. If I remember even my first Montana brochure they were bragging that the cap design eliminated the need for an air foil.

bigmurf · 10-15-2007, 09:36 AM

I had one but did not install it on the new truck. Do they work? Yes just look at the big rigs with them. Of course they get 4-6 mpg on a good day and drive 100,00+ miles a year. JMHO

Mrs. CountryGuy · 10-15-2007, 09:53 AM

This is one of those subjects that tends to set off the buttons on my better half.

We totally agree with bsmeaton and Lonnie B on this one, the front cap on the Montana was designed to be aerodynamic and assist in fuel efficiency.

It is Al's opinion, that there never has been a test that proved that foils work, they cost a bunch of $$ and you would have to drive a TON of miles to get that $$ back on fuels savings, even at today's horrible fuel prices. And, if you bust one of those on your front end of your Tana, and possibly the foil as well. Not sure if insurance is gonna pay, but wowser, lots o damage could happen, and in our opinion, for a questionable possible small, very small, gain on fuel mileage.

So, it is my better halfs opinion, why bother. Just something else to maintain, install, worry about, and pay for.

Here is an idea, go to the Home page and look at the photos of all the members rig. I just did that, and found only 1 truck with foil installed on the page that I previewed. Must be some reason that most of us don't use one.

That is our opinion, don't mean to insult or ruffle feathers, take it for what it is worth to you.

Good luck in your decision.

bncinwv · 10-15-2007, 10:01 AM

Possible benefit as a glorified bug deflector??? Is the money worth the elimination of the hand labor of removing bugs from Monty front cap??? Just a thought, I don't have an opinion and don't have a deflector.
Bingo

DONnANNIE · 10-15-2007, 10:17 AM

Quote:

quote:bncinwv Posted - Oct 15 2007 : 4:01:46 PM
Possible benefit as a glorified bug deflector??? Is the money worth the elimination of the hand labor of removing bugs from Monty front cap??? Just a thought, I don't have an opinion and don't have a deflector.
Bingo

Bingo, you forgot, you'll have to clean the deflector on the TV

LOL

bsmeaton · 10-15-2007, 11:39 AM

Too many times these gadgets are sold based on untested theory of benefit, such as the Airstream trailer or flow-through tailgates. All of these things appear to properly redirect airflow for better efficiency, but when actually tested, they do not. After decades of being called the "slipstreams", Airstream trailers proved to be worse than any RV design in history when tested in a real windtunnel. The flow-through tailgate proved to actually disrupt the manufacturer design airflow over the back of a pickup enough that they actually reduce fuel mileage!

Wary be the consumer!

BTW Bingo - after you install the airfoil to catch the bugs, I have a great little sonic bug repellent device you can install that will eliminate all the bugs on the front of your vehicle. Call now and we'll send you a second one FREE for your other car

Glenn and Lorraine · 10-15-2007, 11:49 AM

Quote:

quote:Originally posted by bigmurf

I had one but did not install it on the new truck. Do they work? Yes just look at the big rigs with them. Of course they get 4-6 mpg on a good day and drive 100,00+ miles a year. JMHO

Yes they do work on tractor trailers BUT take a close look at one of them big rigs. The foil is right tight to the trailer with little or no space between the tractor and trailer. The air must go up and over or around the side. No air gets between the tractor and trailer.
However the air foils on pick ups sit way to far ahead of the trailer and therefore create more of a drag between the foil and trailer. And YES this has been proven but I have yet been able to find the website.
Another huge energy saving myth is running with the tail gate down, no tail gate or the louvered V gate. This has been proven to actually decrease fuel mileage rather than helping fuel mileage.

stiles watson · 10-15-2007, 11:51 AM

The only ones I have seen on pickups put the uggg in ugly. I think air foils fall into the same category as leaving you tailgate down to get better mileage. Mythbusters proved that is a myth. According to my feeble calculations, you would have to pull your rig over 12,000 miles to break even. That is if (and that is a big "if") you gain 1 mile per gallon while pulling with the foil.

I may be wrong, but from what I think I know about aerodynamics, when not towing, the foil would create a drag vortex that would have a negative effect on non-towing mileage.

As has been said, the nose of my Monty is not squared off like the nose of a box trailer. It has aerodynamics built into the design. So to compare our rigs with semis and trailers is an apples and oranges comparison.

richfaa · 10-15-2007, 11:52 AM

Take a good look on the wind deflectors on the the big rigs. They totally encase the cab and trailer to deflect the wind and make the entire truck and trailer appear as one unit.. Not so with the Rv/ Camper setup. there is plenty of room for the wind to get around the truck and into the pickup bed Throw some light stuff in your pickup bed under the nose of the 5th wheel and see what happens..No way a cab mounted defelector is going to deflect that wind.

dieselguy · 10-15-2007, 03:21 PM

Tried one when I had an F350 with a 460 gasser ... did a darn good job keeping the bugs off most of the front of the camper, but as far as the claimed fuel milage increase of the manufacturer ... never happened. I drive 63 - 65 mph. On a positive note .. sold it for what I bought it for to a guy that was actually looking for a high priced bug deflector for his horse trailer!
On Edit: Another consideration is most will not fold down enough on a 1 ton to clear an 8' garage door, so truck sits outside.

bncinwv · 10-15-2007, 04:18 PM

Okay people!!! I can pressure wash the bugs off of the deflector I don't have which is a lot easier than hand scrubbing the Monty cap with the bounce sheets that I have left over from de-mousing.

Brad, we need to use the bug repellant on our signatures (give me one and you can keep the free one for your signature) since we seem to have a bug infestation that is permeating our computer screens. They are starting to multiply since I now see them in other places too

Bradln · 10-15-2007, 05:34 PM

The last time I bought tractor and trailers for work. It was made clear that the airfoil on the truck was not as beneficial as to have a trailer with a slight bubble front. Sound like what is on the front of the Monty already. The truck suppliers were actually pushing the trailer bubble instead of the foil.
I do like the bug deflector idea though.

Dave e Victoria · 10-15-2007, 09:21 PM

The air dams on the top of the truck are totally worthless for fuel savings. As has been said, the distance between truck and trailer is just too great. Moreover, the dam is not high enough to deflect air over the top of the trailer. A better approach would be to create turbulance in the air flowing over the top of the truck to reduce the laminar flow pressure on the front of the trailer. Even this will effect will be minimized due to the streamlining of the trailer front.

However, If you are still looking for something to save fuel, you need to break up the laminar airflow around and over the BACK of the trailer. This area is not stream lined. The laminar flowing air sort of stays together and creates a low pressure vacuum drag. There are companies selling little strips of 1 inch tall deflector vanes that are mounted in the airstream right at the corners of the rear of the trailer. These deflectors, called vortex generators, cause little turbulent flows that destroy the laminar flow pattern and reduce the vacuum. They are especially effective on boxy eighteen wheelers. The down side is they stick out and are easy to get hooked on or injured on and are not very attractive. Airtab LLC makes a design especially for trucks that have eliminated the jagged edge problem and are more attractive and might work well on a fiver. They claim 4 to 8 % savings for a big rig.

Vortex generators have been used for many years in aviation where they are mounted in a row along the top of the aircraft wings to help improve low speed behavior. Next time you are in an airliner, look for the deflectors. They look like little one inch tall vanes sticking up from the surface of the wing and are usually found forward of control surfaces. A row of these over the top of your tow vehicle would do more good than any big ugly airdam.

Dave

richfaa · 10-16-2007, 12:16 AM

Was waiting for you to come along Dave.. You have a way with words...Great explaination. We may try those Vortec generators .One of the campers in our local group, a retired trucker, has them on his Rv and swears by them. Will Google airtab.

Dave e Victoria · 10-16-2007, 04:04 AM

Rich
Try this
http://www.expresstrucking.com/Airtab/airtab.html
Dave

PS Thanks for the kind words

bsmeaton · 10-16-2007, 04:35 AM

I imagine all the hardware we have hanging on the sides (awnings, fenders, vents, etc.) almost negate the use of anything that would improve air flow down the sides, or even the top of our rigs. I'm just not seeing anything real aerodynamic about those awning arms

.

richfaa · 10-16-2007, 05:13 AM

We are beta testing a guage for www.aeroforcetech.com The "interceptor scan guage." There are many changes on the 08 Ford 6.4l in terms of what the OBD2 date port is looking at. The device was developed by a couple of Aeronautical engineers here at NASA's Glenn Research center. They are only a couple of miles from my driveway so we are having some fun. We are giving them the problem of how to make the truck and RV combo more areodynamic..should be interesting. Thanks for the web site.

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