da Rock

Chuckle chuckle.... not only does it sit in the fuel very close to the pickup location, but if it's in a plastic tank you can see bubbles blowing out as you run it (like on the bench breaking in). It really blows your mind to see it in operation, especially if you are skeptical of the whole deal to begin with (which I was years ago).

I still don't believe it works, but it does in spades.

The idea is sorta twofold.
First, the theory is that the pressure the pickup experiences is lots more constant that if the pressure is entering the tank far away. Only problem with that theory is that pressure is supposed to be constant everywhere according to high school physics right.
Second, the theory is that if the pressure input is from some place in the tank that is covered by fuel awhile and not covered by fuel awhile, the pressure experienced by the fuel pickup opening will fluctuate. Seems that high school physics teaches other than that as well.
Truth is that it works great and for whatever reason it really simply works great.

I sorta feel that the covered/uncovered deal is why it works. But don't worry about the why.

It really helps control line stunters because they encounter way more g-force in their 5' radius turns than most RC planes ever feel. But it really isn't a big deal in RC planes. I use both and both work good for RC.