I'm a better RC pilot, designer, and builder than when I started, but I'm still very much learning, including when it comes to aerodynamics theory. I'm a hands on trial and error kind of guy, so sometimes I just grab something I see and try it. I saw this article on a proposed low aspect NASA design that is what I call a "tail topper", a small, swept horizontal plane atop the vertical stabilizer, but not a full t tail. What is the proper name for this, and what are the aerodynamic principles behind it? The maiden flight of my RET extra slender delta was super sketchy, but on a repair I stuck one of these thingies on it just to see what would happen, and it's been handling so much smoother ever since.