Truckers

[Cd]

A couple of months ago, I was on my way to work at approximately 3:15 -3:340 A.M.
My route takes me through an industrial part of town ( Austin, Texas ).
In the lane beside me I saw a semi that had a trailer with a full Kamm back, as well as wheel covers.
( This design actually had the trailer with a sloping roofline, unlike some designs that have what looks like a rounded 'hottub' strapped to the back of the trailer. )
Of coarse I did not have a camera with me, and I was running late for work.
I have to wonder if they were testing some new prototype. I truly hope so.
My jaw dropped when I saw it and I almost ran off the road.
I work in shipping unloading trucks, and so I know how that some ideas will not work because they would not be practical.
I wonder how that the Kamm back design that i saw works in real life, since you must drive a forklift in the trailer.
I see a lot of semis that are driving back to their RDC center without a trailer, and I have to wonder how hard that it would be to rig up some sort of accordian type of Kamm back that could be pulled out from the back of the cab.
Once the rig had to dock with the trailer, all the trucker would have to do would be to pull back the thing ( or if he's feeling lazy just back into the trailer and the thing would fold itself up.
Not only could it be inexpensive and easy to set up, but it would pay for itself many times over , not to mention the fact that it would not obstruct the truckers vision or add practically any weight.
Also the Kamm back could extendd back to the trailer and fill in the gap between the cab and the trailer. In a corner, the assembly would flex since it would be like an accordian.
The city of Dallas already has stretch busses with this feature. ( The bus has an accordian like structure in the center portion of the bus which flexes when the bus goes into a corner.

[Arminius]

Cd, I must have seen the same kind of truck, last year. The one I saw had no name or labels on it. My impression was that it was some kind of specialty truck. I once saw a similar truck at the EAA, carrying - of course - a plane with folded wings.

[Chris D.]

Originally Posted by RH77

Next, the whole rig can save rolling resistance with single instead of dual wheelsets:

You've definatly never driven truck before..

duals have less tire on the road, so youd be adding MORE tire to the road with a large wide setup..

with a large wide single the back end of the truck feels too loose and gummy,
its a looks thing and you wont see it too oftin because its dangerious when hauling.

I had to drive one and it was not a pleasent feeling..

one of my 2 favorites are the Volvo (monster engines) and the Freightliner Conventional S/T's safest around IMHO..

Both very aero..

[aerohead]

In the 1980s,Fruehauf teamed up with Peterbilt,and came up with a concept that got 10-mpg.It had all the goodies,including a boattailed trailer.Its never been produced.Truckers I know really consider weight an issue,as it cuts into payload potential.Aero mods will have to be very light with respect to size and effectiveness.Two points mentioned by members want to touch on.The single "floatation" wheel/tire combos offer 20% less rolling resistance than duals,in spite of increased frontal area.Blowouts suck though.Secondly,BMW and The Waggoner's Trucking Co.,of I believe S.Dakota,both run a fiberglass boattail on their trailers.The Waggoners get to run additional length,drivers don't know anything about any economy gains,perhaps the headquarters could respond to that.I've always been to busy to follow up on it.Left to me,I would completely re-design tractor-trailers,and I'm sure all the current builders would hate it completely.

[RH77]

Originally Posted by Chris D.

You've definatly never driven truck before..

No, nothing with a tandem-axle setup -- the largest were straight-chassis 6-wheelers. Largest stuff was Fire Apparatus: 1800 gallon tanker, pumpers, ladders, rescue, Medium-Duty ambulance box (Freightliner) -- mostly an easy driving E-350 Ambulance conversion.

duals have less tire on the road, so youd be adding MORE tire to the road with a large wide setup..

Multiple studies (including those of the EPA), prove otherwise. The Green Car Congress thread has a link in the story to the study mentioned and likely other studies for more info.

with a large wide single the back end of the truck feels too loose and gummy,
its a looks thing and you wont see it too oftin because its dangerious when hauling. I had to drive one and it was not a pleasent feeling..

Good info to know. I do see them more on trailers, which makes sense from the stability standpoint. I can appreciate the gummy feeling -- the company once ordered new tires for the E-350's, with too weak of a sidewall. The back-end was really yawing in level driving -- had to take them back. Not good on high-performance/response cornering either.

RH77

[meemooer]

I was just at the Mid-American Truck Show[MATS] last weekend, and running a "super single" as they are called does improve rolling resistance, and does help with weight. Most truckers from the show said they would rather run those after driving on a set, but the cost is too much for most to make the switch. There was a few vendors with full side skirts the the trailers. They had hinges on them so they are less likely to break off, instead they fold under the trailer. A few manufacturers had new rigs set out for aerodynamics to increase gas mileage. Using lighter materials to build the cabs, and a few design changes in the front end to help with CD.

[Chris D.]

one thing the duals have over the "super single" couldnt remember the term, thanks..

When one of the duals turns alligator,
you still have something to rely on to get you off the road safely..

with a super single, your done..
pull it over and change your log because your no longer making money.

This mod is to Rigs as spinner wheels are to SUV's/trucks.. uesless showoff crap..

[meemooer]

actually i think they run intertubes, like in NASCAR, so if they do have a blow out, they will still have a few inches of rubber, so they can safely change in. Even with duals, if you have one go out, then you still have to pull over to change it because then the weight bearing tire on that axle may not be able to handle the added stress.
i don't really remember it all, i was exhausted when we even got to the show, so i'll have to call my more alert buddies on what they remembered about them.

[DifferentPointofView]

if your a self employed trucker... a new rig ain't gonna be cheap. It's like buying a new prius, or stick with the old beater. how long will the gas save you to make up for the 20grand you spent on the prius?

I think that modding the back is a bad idea. if you boat-tail, people in miata's and small things will get in there and tailgate... that' ain't gonna be pretty. The best bet is to smooth out the front and get rid of Cd there. as well as some frontal area drag.

[trebuchet03]

Originally Posted by DifferentPointofView

I think that modding the back is a bad idea. if you boat-tail, people in miata's and small things will get in there and tailgate... that' ain't gonna be pretty. The best bet is to smooth out the front and get rid of Cd there. as well as some frontal area drag.

At these speeds - the trailing edge will show much more significant gains. But, given the longness - I'm fairly certain flow has gone turbulent by the time you reach the end of the trailer....


In any case - you're right about the cost of things.... The cost per ton for a semitruck, as it is now, is pretty cheap. Not comparable to rail, but much cheaper than any of our cars or trucks. I really need to find that fuel and efficiency breakdown by industry chart....