ORIGINAL: speedracerntrixie
Round off only the leading edges and leave the trailing edges square. The added turbulence does two things, first it actually makes the surface more powerful and feel tighter around center. A side benefit of this and the flying wired is that it adds a good deal of drag to the tail. This will lead to better tracking. Imagine it working the same as feathers or quills at the tail of an arrow.
This concept is interesting. It appears that one of the recent trends in F3A is to use "flaring TE" rudders. These rudders taper rearward and then flare out producing a wider than control surface LE. So far, I have only seen this done on rudders which makes sense. In some cases, the width of the TE is adjustable or in some cases the rudder is split so it can be used as a spoiler of sorts inducing drag in downlines. I'm not sure how all this plays into F3A regulations but the evolution of design is always interesting. This one definitely has to go against all the aerodynamic book rules written 30-40 years ago!
David.