Holy boat tail Batman

[srortega]

I just saw this on Gas 2.0 and thought I would share...


The tapering tail is no secret among scientists for improving stability and fuel efficiency. Many high-mileage concept cars feature just such a design to smooth the aerodynamics of the vehicle. Now imagine applying the same concept to container trucks that log more miles in a year than most of us travel in five.
A Dutch public-private enterprise did just that, adding a 6 foot long tail to the end of a tractor trailer truck. The results from two years of testing were a 7.5% increase in fuel efficiency, and thus a similar decrease in emissions.
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[Old Tele man]

...could lend a whole "new" meaning to the old 1950's phrase "duck tail."

[Piwoslaw]

The underside looks dirty:
1) There is a step between the rear taper behind the wheels and the bottom of the extension,
2) What is that bumper/platform sticking out under the extension? It just kills any airflow from the underside.

Also, rear wheelskirts would clean up the sides.

[Christ]

Piwoslaw - That thing is a bumper extension. It would probably be a legal requirement wherever that truck is, and here in the 'States, the bumper is supposed to be the furthest point of the body fore and aft, so it would be a legal issue to not have it here, as well.

The bottom panel of the extension is lifted up so as not to cover the tail lights. A more cleverly designed setup would allow complete lower attachment without compromising the tails, possibly by integrating them inside the "dead" area of the extension. Ranging and lighting position laws apply, as well.

[wagonman76]

I wonder how the 3 single wheel axles compare with 2 dual wheel axles. There are 6 tires instead of 8, however there is another set of bearings.

[NeilBlanchard]

Hi,

The frontal area of 3 single wheel axles is smaller, too.

[Christ]

The frontal area isn't going to be much less because those are extremely wide tires, like are becoming more and more commonplace as replacements for duals on commercial trucks over 5 Ton.

Also, the rolling resistance is decreased with those tires as compared to a set of duals on the same axle, but I don't have numbers to cite or compare to determine if the difference makes up for a third axle vs two axles with duals. The bearings could be considered ~95% efficient, IIRC, for calculations.

[wagonman76]

Never seen tires like that before. I figured it was because it was European, they tend to get efficient innovations before we do.

I thought about frontal area, but first there do appear to be duals on the tractor anyway. Then the skirts on the trailer to block a lot of airflow.

[Christ]

TBH, I only see single tires on the tractor... not even wide ones, just single tires that you'd normally see in a dual setup, some 9" wide.

Rather odd, at least, single axle truck and a triaxle trailer. Mustn't be carrying too much, I suppose.

[Piwoslaw]

Originally Posted by wagonman76

Never seen tires like that before. I figured it was because it was European, they tend to get efficient innovations before we do.

Most European trailors are 2- or 3-axle, all have single tires (never seen doubles). Often, in newer models, the first of the three axles can be raised when there isn't much load, reducing RR. Also, European tractors usually have only one rear axle, with double tires. Sometimes there is a single-tire drop axle preceeding the main axle, but this isn't very popular.