Skirts

gotta go

Veteran Expediter
That is a consideration with the skirts is how low do you go before causing a problem getting into some docks?
That is a definite consideration. At least 3-5 times a year, I'm unable to back into a dock due to my truck sitting too low. Let me know if you want me to measure my ground clearance for you.
 
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TeamCaffee

Administrator
Staff member
Owner/Operator
We have had a couple docks that we could not back into or docks that scraped the bottom of our generator. The lift gate has also scraped a couple of times as it is low.

The Enemy the under carriage thing will not work in this situation due to the lift gate.

Henry has removed the rear air deflectors from his trailer as the company has decided not to product them for the public. I do not know now what he will try but it is something he is still pursuing.

I found this article to be very interesting in a trailer building magazine:

Ease the Turbulence
 

purgoose10

Veteran Expediter
We have had a couple docks that we could not back into or docks that scraped the bottom of our generator. The lift gate has also scraped a couple of times as it is low.

The Enemy the under carriage thing will not work in this situation due to the lift gate.

Henry has removed the rear air deflectors from his trailer as the company has decided not to product them for the public. I do not know now what he will try but it is something he is still pursuing.

I found this article to be very interesting in a trailer building magazine:

Ease the Turbulence

That's a very interesting article. One thing that I am interested in and was going to ask you is the wheel covers. I see by the article that they could save 1% in fuel. What I'm interested in is do they block the cooling effect on the brakes causing excess wear?? Do they offset each other??
 

Rocketman

Veteran Expediter
I've seen the heat/lack of cooling mentioned a couple of times. It would be my opinion that skirts would have no more...or less... effect on cooling of the drive axle/axles than the factory fairings installed on a large number of new otr tractors.

Also, aftermarket fenders have been available for years that would block more air from the tire/wheel/hub assembly than any fairing or skirt. I have never heard of these fenders causing heat/lack of cooling problems. But....that is where I would look to see if there is any reason for concern.

My guess? Nothing.....no concern whatsoever.
 
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Rocketman

Veteran Expediter
To the original post. If I were ordering a new truck, i would order it with factory fairings to the back of the sleeper, from there I would likely use side boxes starting as close to the fairings as possible. If I decided to use a skirt, it would start behind the boxes and continue to the first rear axle. Built and installed correctly, there would be little or no loss of efficiency imo. Considerations would be taken for access to the generator or any other servicable component hanging fron the side rail. I would also want fairly easy access to get under the truck, in front of, the axles. This could possibly all be done with one removable panel on one side...including access to the generator.

At the rear, I would have skirts similar in appearance to what you see in the link Phil provided. You would have to work around the liftgate and liftgate controls obviously.

I would in no way have anything directly behind the axles that would block airflow behind the axles. Example: no toolboxes or solid mudflaps, etc. Once the air has made it to that point, its not going to hurt you anymore unless you re-trap it with something. If the liftgate still has air that could get to it, i would consider something that could mount to the highest point possible just behind the axles, full width of the truck, angling down and toward the rear as far as possible and serving to deflect the air down and under the liftgate. This is, of course, the same principle as the wedge type fairing mentioned above. You may need something similar, but yours would have to be custom built to work around and in conjunction with the liftgate. A flat piece of material installed correctly will divert air just as well as that big plastic wedge...imo.
 

Doggie Daddy

Veteran Expediter
To the original post. If I were ordering a new truck, i would order it with factory fairings to the back of the sleeper, from there I would likely use side boxes starting as close to the fairings as possible. If I decided to use a skirt, it would start behind the boxes and continue to the first rear axle. Built and installed correctly, there would be little or no loss of efficiency imo. Considerations would be taken for access to the generator or any other servicable component hanging fron the side rail. I would also want fairly easy access to get under the truck, in front of, the axles. This could possibly all be done with one removable panel on one side...including access to the generator.

At the rear, I would have skirts similar in appearance to what you see in the link Phil provided. You would have to work around the liftgate and liftgate controls obviously.

I would in no way have anything directly behind the axles that would block airflow behind the axles. Example: no toolboxes or solid mudflaps, etc. Once the air has made it to that point, its not going to hurt you anymore unless you re-trap it with something. If the liftgate still has air that could get to it, i would consider something that could mount to the highest point possible just behind the axles, full width of the truck, angling down and toward the rear as far as possible and serving to deflect the air down and under the liftgate. This is, of course, the same principle as the wedge type fairing mentioned above. You may need something similar, but yours would have to be custom built to work around and in conjunction with the liftgate. A flat piece of material installed correctly will divert air just as well as that big plastic wedge...imo.

Objection your honor, this is just hearsay and speculation on this posters part, as I do not believe that he owns or has access to a wind tunnel to prove these theories.

Next he'll be telling us that he can SEE the wind much like Dale Earnhart Sr. claimed.;)



Sent from my DROID BIONIC using EO Forums
 

Rocketman

Veteran Expediter
Objection your honor, this is just hearsay and speculation on this posters part, as I do not believe that he owns or has access to a wind tunnel to prove these theories.

Next he'll be telling us that he can SEE the wind much like Dale Earnhart Sr. claimed.;)



Sent from my DROID BIONIC using EO Forums
But.... I can see the wind.... in a dust storm :D
 

ATeam

Senior Member
Retired Expediter
Here are photos of another expediter truck with skirts. Second photo is grainy because it is enlarged.

Rice_truck.jpg


Rice_skirts.jpg
 
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RETIDEPXE

Veteran Expediter
"full width of the truck, angling down and toward the rear as far as possible and serving to deflect the air down and under the liftgate."

Rocketman, here's kinda of what I envision you mentioning, the angled down dual wing running across, maybe someone can come up with a drive shaft thru model. They are claiming 9% fuel econ increase but their amount of testing is laughable, like 2 runs plus one owner report, not a very controlled test bed. At $3499 each, a little more testing would be warranted; Photo_Page

The 49'r in Sacramento has a deal on trailer skirts for $1695 installed, a metal ribbed type, almost looks like a ribbed metal roof panel but a heavier gauge steel I'd imagine, curvature at the rear for wheel cutout.

I bought a take off fiberglass bed cover for $200 from a used truck dealer and cut it up for tool box skirts. So far on the passenger side. Given some time I will get the other side done and compare mpg with and without as they are quick dismount, a hotrod hood pin post/spring lock on the front and two rubber lined mazda sway bar clamps at the rear. Been on for 5 months or so now so you can see how much of a hurry I am to get the other side done hehe. Moving the boxes forward was considered but already a little heavy on the steers as it is. Skirts weigh roughly 25 lbs each with hardware.
 

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GandJ

Active Expediter
Linda,
Really liked the link to the article. Good read.

I wonder if this would fit or be in the way? Interesting design in front of the rears.

As stated it may deflect air but will clearance be an issue. They are being used now but how many will we see on the side of the road in pieces?

UT-6SideConfiguration.jpg

click on for a larger view
 

TeamCaffee

Administrator
Staff member
Owner/Operator
GandJ I heard mixed reviews on this configuration and like the article I am skeptical of the reviews at this point. They solve the problem in California but I have not talked to a driver with real world experience.

On the panels that curve out to the tool boxes interest me as from what I have read the curved skirts are not as affective as the straight skirts. That might not be the same on an expediter that has a lot going on underneath. I know of a few people who have covered the cross members under their trailers which has also helped their fuel mileage along with their skirts.
 

petercar

Active Expediter
Linda,
Really liked the link to the article. Good read.

I wonder if this would fit or be in the way? Interesting design in front of the rears.

As stated it may deflect air but will clearance be an issue. They are being used now but how many will we see on the side of the road in pieces?

View attachment 5334

click on for a larger view[/QU

I seen this on a trailer on 294 Sunday looked pretty nice set up
 

BigBusBob

Veteran Expediter
Driver
I've found this entire thread to be very interesting. While I'm not on the forums near as much as I used to be, I still like to hop on and at least read. This particular thread has become useful though, for me... In English. I'm currently driving locally, and still doing regional with the tour busses and limo's. I'm also however, taking up welding thru a local tech school and have had to take english and math as well. I've used some of this information within this thread (with credit given where it's due- in cases of quotes) for a recent english paper that I chose to research concerning fuel mileage.

I'm loving welding though, and have progressed thru brazing and stick welding and getting ready to start MIG, then TIG. I'm also taking Blue Print Reading for welders, which is also very interesting. I'm going for a full welding certification to be MIG/TIG certified. I'm also considering Diesel mechanics... then I can go back to long distance driving with a 100" bunk, and belly boxes full of tools, jacks, a compressor and welder!!

A serious comment though from me: why not hide your belly boxes with skirts that also serve as doors for the boxes? You'd be saving weight to a certain extent, and still maintaining the objective to save fuel and make yourself more aerodynamic.

As far as skirts getting in the way of docks, an easy solution would be to fabricate them so that they are hinged and could be folded up and "clipped" up out of the way or swung up 90 degrees so that a dock could be handled easier.

Consider looking at how some racing trailers and haulers are fabricated for fuel conservation.

That's all I have for now, thanks for helping me with my "Annotated Bibliography" assignment.

BigBusBob, still rolling around.

Kicking around the idea of adding skirts to our truck from the steps to the back and would like some input.

One way is to use the same sheeting and cover the belly boxes and lift panels to get into the belly boxes.... This brings up a problem of how to hold down the skirts tight so they do not flap. I thought of a pin and cotter pin configuration.

Another is to skirt in between the belly boxes clear to the back of the truck. This seems ragged to me but it might be the best solution.

Any thoughts you guys might have?
 
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