More semi aeromods
 

I hadn't seen aeromods like this before. I've really just seen the tails and side skirts. I'm not real sure what part C does... Anyway, just more ideas to chew on.

Aerodynamic add-ons reduce fuel consumption of semi trucks by 7-12% - Autoblog Green

http://www.blogcdn.com/green.autoblo...1297447593.png

I wondered about part C also - and guessed it's to send air around the "bumper" / structure rather than through it.

AND... I wondered if these were replacements for the side skirt approach. Not really necessary if there are skirts, I don't think.

I would think those would be in the way and collect more winter grime than a pair of easily removable side skits that are flexible. It was just a couple months ago someone posted a company that made skits that would flex if they hit something, but held their ground at 65mph. They also flipped up or removed and could be placed completely out of the way for servicing the trailer.

I don't think these current renditions are a great step. but at least someone is thinking about the problem and making solutions, even if they aren't the best ones.

I was under the impression too that the "A" deflector was wider and routed air outside the rear tires as well. I see in this rendition such is not the case. Wonder why that is?

Some Interstate roads allow dual 48 or 53ft trailers to be hauled in tandem by a single truck. Also, 3 triple trailers (pup) are hauled by a single day cab. Wonder if there would be any mpg gain if drivers only hauling single could hook to a purpose built 'boat tail' style trailer and haul tandem?
Used to drive loads from Anderson, IN to Tonawanda, NY. I-80 / 90 allowed doubles / triples.
VT247

About "C" I think first goal is to prevent cars to go too far under the truck in case of rear collision to save the life of the inattentive driver. This is mandatory in Europe.

Denis.

It's mandatory here in the USA also and is called a ICC bumper.

ICC
Acronym for Interstate Commerce Commission. The U.S. federal body formerly charged with enforcing Acts of Congress affecting interstate commerce. The ICC was decommissioned in 1993.


ICC Bumper
A bumper typically made out of 3" to 4" steel channel stock, usually about 75% of the width of the trailer, suspended half the distance from the trailer floor to the pavement with a strong enough bracing to meet federal regulations governing underride guards.


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Part C is shown st the same height as the ICC bumper in the picture.

I don't really understand Part C. It it were as wide as the tires & tapers up to the ICC bumper, I think it would work better. It would also then take the place of the mandatory mud flaps, which would still be required.

I talked with a representative of Smart Truck today. I asked him the purpose of part C. He explained to me that part C was a rear diffusser and that the whole Under Tray System was designed to compress and tunnel the air. Thus speeding it up before entering the low pressure area. If you look closely at the bottom of part C you will notice a slight downward angle that helps with final compression.

I told him about this website so maybe he will chime in later.



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Bingo!
 

That's the $Trillion idea! If you're first to the Patent Office and you can obtain venture capital for commercial production you'll amass a fortune that would make Xerxes blush.

'compress'
 

He probably should not use the 'compress' and compression' as terms to describe what his product does.This phenomena would not begin to occur until around 250 mph.
Better that he should say it 'accelerates' the flow which actually lowers its pressure.
It's hard to imagine that it does anything other than ride in the wake of the first component ahead of the wheels and the wheels themselves.

He should have just said the Venturi Effect

I may have interpreted what he said and came up with the word compress on my own.

The trailer pictured has sliding tandems. They are normally slid foward for city driving (less turning radius) and slid back for highway use or anywhere in between to get the correct maximum weight per axle allowed by law.

When the tandem is slid back for highway use, the reason for having part C in the system then becomes more apparent. IMHO.

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venturi
 

I see where you're going,but I believe that without an 'enclosed system' which a venturi is dependent upon,there is nothing present( as the wall of a carburetor) in the local flow environment to 'force' the acceleration around or under.

I dont know if same patent laws apply to states, but in europe if you say your idea that clear in some forum you cannot apply anymore patents to that idea...

There are trailers already in europe which look like boattails, so it would be very hard to get patent for something which you just do more longer boattail.

photos?
 

Vekke,if you come across any photos of these trailers it would be great for you to post them.
Once a person can 'see' that something has actually been done,it somehow validates the concept,and all of a sudden it's worthy of application.:)

No personal photos, but is this enough for starters?

Radical Aerodynamic Semi Truck With 0.29 Cd Offers Dramatic Fuel Savings | The Truth About Cars

not so curvy kammback trailers is on finnish roads. I dont know if someone has modified his own trailer or do some trailer company build that kind of models :/. I will try to remember take some pictures next time I see one.

DHL teardrop trailer - Google Image Search
http://www.igd.com/content/Images/EC.../teardrop1.jpg
http://www.logisticsmanager.com/asse...iAssetID=20434

i should have stated that as a general description, not a literal term(for example, standing between 2 building will cause you to experience an increased wind velocity but technically isn't a venturi since it's not enclosed). reduce the area for the fluid to flow through and you will increase it's velocity, and reduce it's pressure, likely that piece on the back wouldn't do very much of that since it's no in contact with the ground and therefore doesn't fully enclose the air path underneath, but it is close

Another whole truck aero-design.

Huw Evans | Sep 17, 9:02 AM
MAN Concept S Adds Aerodynamics to Big Rig Cab; Looks Like Optimus Prime’s Head | AutoGuide.com News
http://www.autoguide.com/auto-news/w...oncept-S-2.jpg

My first thought was to make the bumper sections airfoil-shaped.

Rear-ending a collection of air-foil shaped structures, into the pointy ends, is probably a good reason to not ever do this.

http://images.thetruthaboutcars.com/...romlinien1.JPG

Is it me, or do the "air lines" not follow the curve of the truck? It looks like it actually tapers too much.