tractor fairings pros/cons

Ground effects?! If I had a truck with that I'd get rid of the stacks and run side pipes like an old Corvette.

 

I've got a buddy with a few rigs that hauls paper with two identical Columbias, except one doesn't have the fairings. The one with fairings averaged 7.6mpg last year, and the one without them averaged 7.8mpg.

Take a look at all the Volvos going down the road with their fairings blowing out the sides of the truck and tell me how trapping all that air on the most non-aerodynamic surfaces of the tractor (battery boxes, hoses, oil pan, gearboxes, catwalk plates, etc) is going to help with fuel economy.

 

Using your logic an Indy or F1 car will do better if it was shaped like a brick. You really think aero has nothing to do with economy?

 

Hi Dryver, I was going to say something too. So many variables there. Where have all the flat nosed cabovers gone? An arrow goes through the wind better than a box.

 

F1 cars have lower valence and belly panels that have been wind tunnel tested and tweaked for downforce. Tractor fairings are more or less for show, especially after some wear and tear. None of the 10mpg+ trucks rely on factory aerodynamics.

 

[QUOTE="semi" retired;4224231]Hi Dryver, I was going to say something too. So many variables there. Where have all the flat nosed cabovers gone? An arrow goes through the wind better than a box.[/QUOTE]

Cabovers are gone because they're a pain to maintain, and there are no longer legal restrictions that make them a necessity. Lower frontal surface area has more to do with drag coefficient than you might think.

 

If you look at the European trucks you will see a lot of cabovers.

 

I'm not sure but I think it has something to do with length laws.