Air foils on trailers?

They don't make much difference. The main reason the big carriers get them is to be a Smart Way certified carrier.

 

They also keep fast and furious wannabes from thinking they can zoom under my trailer lol

 

Replacing 150 trailers in our fleet brought our fleet average up 2/10 of a mile. That was appx 30% of fleet. Now we have new motors and trucks coming online so we are not getting valid results however in my truck pulling a load I had done 100's of times I was gaining almost 4/10ths by the fill up math which could be off because of temp, ground level........


They also help in the wind. Seems like they would be less stable but I found they actually handled better.

 

I thought so too. Of course I studied cows not aerodynamics. Has to be something whith cutting the cross wind out from underneath if I had to guess from the water spray in a Florida thunder boomer.

 

In addition to these panels under the trailers, I have noticed these tent looking contraptions installed on the rear of trailers installed over the trailer doors. So far I have only noticed them on schnieder trailers.

 

Creates a negative ground effect just like race cars. Sucks the trailer downward and does not allow wind positive pressure to get underneath causing lifting.

 

Mesilla Valley Transportation here in El Paso uses those boat tails.

 

I agree that they dont make a huge difference on one truck pulling them but i think the little difference they do make would add up to a noticeable amount with a large fleet all pulling them. I noticed that the newer hard plastic type make a more noticeable fuel saving than the older aluminium type did.