Yeah, nothing to do with airplanes, but it does involve cutting drag.

Lately it seems like all of a sudden about 1 in 10 big rigs I see have some kind of big white fairing UNDER the trailer, as near as I can tell it must be for fairing the running gear.

I seem to recall some here claiming to be truckers (not sure if they were complaining or bragging). Fill us in: what are these, what are the benefits, and there must be some pretty good ones judging from how many I'm seeing in a pretty short time. Remember when big rig tractors wern't faired, and nowdays you'd be hardpressed to find one that wasn't? Cutting drag, it works every time it's tried.

I agree..see a lot more of these rigs traveling I-80..I'm sure it's to reduce drag. What I'm wondering, in the wintertime, how much ice & snow these devices will pick up and how much weight will the stuff add?
HC

Years ago, maybe 30, there was a good article in the SAE journal regarding the effectiveness of various aero improving modifications for trucks. It has been interesting to see them become the norm, rather than the exception. I don't remember fairings for the undercarriage, though. Wouldn't surprise me, though, since the air dams on the front of cars and pickups have proven to be a reduction in air drag. Maybe they will also improve the nasty spray encountered when passing them, too.
tom

My cousin is a engineer for Freightliner. There is a slight increase in fuel economy. Some companies are playing the GREEN card and use this to show how enviro aware they are. If you want to haul for these companies you must have them on your trailer.

it's more than a slight increase. they eliminate a lot of drag. Expected fuel mileage increase is anywhere from 6% to 10%. When applied to a truck thats extremely significant. My father is a trucker, I do his books. He spends over $60,000 in fuel for just one truck each year. saving 3600 to 6000 would make him quite happy.. might pay for his trip to fish alaska (gave up on caps, shift hates me today)

Rob and Guardian Aircraft are spot on. I also heard a rumor that good ole California is at it again. Someone had told me (and I have not verified this) that CA. is on the prowl to require every trailer registered and coming into their state to be equipped with these fairings. I dunno, but I wouldn't put it past CA.

Oh, and yes, I'm a real trucker. Not a poser! And never mean to brag!! Just a yahoo trucker trying to make a dime so I can spend a dollar flying

Yes yet more technology for me to buy. Actually I don't have to participate in this forced feeding as this will only affect 53' and longer trailers and I run 40' & 42' tankers in my fleet. California has adopted the "this is how it's gonna be boys" game plan.

There is a lot of good reading at the link below but to summarize, if you're going to run more than 100 miles from your home base you will be required to do the following: Trailers 53' and over, not only put fairings on your trailers but you must use low rolling resistant tires on that big rig. All this should save a bunch of money in the long run but it's tough coming up with 20-25k now and not realizing the savings now.

What? So what if you can't afford upwards of $6K-$7K for new tires and $15K for those fairings shoulda thought of that before you got into that game we're changing the rules now. And by the way don't be dropping those fairings all over the roads when they load up with 2-3 thousand pounds of ice and snow or we'll cite you for that too.

http://www.epa.gov/smartwaylogistics/tr ... logies.htm

We had a truck here the other day with VG's along the back edge of his sleeper. Big plastic stick on VG's. I know from experience that when driving a big truck equipped with quarter fenders, rather than full or half fenders, when driving in rain there is a huge amount of spray that is flipped up and covers your mirrors making it hard to see. The driver with the VG's said they totally eliminated the spray and he loved em. Makes sense to me, keep the air going straight back.

I use and my friend runs the windtunnel where most of these items where tested and when all of the pieces where used on a standard 53' trailer, we saw some significant gains over 25%. That is a huge number, just think there are an estimated 10 million trucks on the road everyday in the US alone. If they all travel around 450 miles per day getting 7mpg, we could save 133 million gallons per day, that is 25% more than was leaking into the gulf....
I thinks all new trucks and trailers should be required to have them.
I also agree it is tough to require current trailers to fit these items especialy since trailers out number trucks three to one.

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This a view from the cab of a Pete I was driving back in 1982. We'd just loaded at a ranch at Avon MT heading back to Iowa with calves. We always said it was like pulling a parachute because of all the holes in the side----don't think there is must that can be done for these "possum belly bull racks".

my fleet average is usually in the 6.0 to 6.25 mpg average I would love to be in the 7.0 to 7.25 mpg or more. @ 900000 miles per year that's saving about $22,000+ per year by a 1mpg increase. That would pay for part of my Pponk motor.

What I would love is a 10% increase in speed with the same fuel burn in the Skywagon, I'm seeing 149mph true with a 10.5 gph burn.

P.S. don't follow bull wagons too close if you just washed your car or truck

In my 1999 KW, I've got the big 550hp CAT, 13spd, 3:55 rears, gross about 77,000#. I average 6.5 mpg most of the time. If I'd be good, I bet my rig would get close to 7.0 or better. What ever the speed limit is, I'm usually cruising no more than 5 over. And my foot in it on the hills (what mountains?? )

Our two newer (2007's) KW's are geared the same as the 99, but with the 565 Cummins. They don't come close to 6 mpg Not sure what the deal is with them.

Glidergeek wrote:
P.S. don't follow bull wagons too close if you just washed your car or truck

Or cement trucks

180Marty wrote:This a view from the cab of a Pete I was driving back in 1982. We'd just loaded at a ranch at Avon MT heading back to Iowa with calves. We always said it was like pulling a parachute because of all the holes in the side----don't think there is must that can be done for these "possum belly bull racks".

Hey 180Marty...I've driven a Few miles with that same view...#3 or #4 in a convoy of "Bullracks" headed up into the foothills of WY bringing out livestock before winter set in. Used to drive a Freightliner pulling a Merritt Pot..used to put those semi's into some tight, narrow places to pick up those ranch cattle..I've actually got some pictures that look very similar to the one you posted...and again, don't park alongside or follow a bullrack too close or your gonna' get a golden shower!