Adding a fiberglass wing to top of truck

Physics, the gull wing is displacing air that would not be displaced in its abscence, this is hardly a controversial statement.

because its an irregular essentially spoiler mounted to the top of a flatroof or midroof, in order to do its job (bearing in mind that spoilers tend to be used in rwd vehicles giving extra downforce on the driven wheels) now while true that it is acting to give downforce, bear in mind physics 101, for every action there is an equal and opposite reaction, the downforce applied is from forward travel and since its pushing down, air is being pushed up. In an ideal world, this displaces a perfect pocket of air just a little above the top of the trailer. But its usually small and angled poorly by installation, which only shoves the air straight up, or too low, its usually not the full width of the trailer, so the corners of the trailer still slam the air with the aerodynamics of a brick.

My point isnt that they werent a nightmare to tweak to actually gain the supposed benefit (better aerodynamics) my point was that you cannot be right that they do NOTHING.

What needs to change? Beats me, take it to a wind tunnel and figure it out, clearly its not doing its job right at present, too many configurations that can change as well though, for pure aerodynamics, its hard to beat a box pulled by a cascadia high roof and fairings or the trailer nosed up as close to the truck as possible

 

These taken together even though pepper was not you, imply the wing does nothing, which cant be true.

Highly finicky, hell, even installed so poorly that a mpg LOSS is possible, but "nothing" is not likely.

That is the sum total of the point you felt so passionately about.

Well, less the cash that someone loses for buying it and how thay goes into the manufacturer's pocket THAT definitely does something, not productive for you, but remember that people buy plenty of crap they never get any utility out of almost daily

 

Yeah, in your case its not going to do anything, youd actually see better mpg by putting on a long sleeper and fairings to close the gap first before doing anything with the top few foot.

Option 2 is go flatbed, aerodynamics on low bars of steel even with a massive gap between truck and trailer is negligible

Ive got an extra 5 foot of frame on my truck and a midroof myself, but i bought it knowing i wanted flatbed, specifically long oversize, dont do much oversize anymore, but i dont pull tall loads or a van unless absolutely neccessary either

 

I did get a boost in mpg with the roof wing it just isn’t large like people would think.

As for the nose cones I tried to get it done to my trailer and was not able to do it. They are literally impossible to buy and install. I called every trailer place in 5 states.

 

Brand new trailers have these on them. Nosecone

 

I ordered brand new trailers and I was not able to get them. Maybe a mega fleet or somewhere else in the country could but I wasn’t able to in the southwest

 

I'm working on my mega status.