Why are some tail wings at the top of the vertical stabiliser and others at the bottom?

Question

Why are some tail wings at the top of the vertical stabiliser and others at the bottom?

Answer 1

Placing the "tail wing" at the top of the vertical stabilizer is an aircraft designers nightmare.  In certain piches the front wing will block the air flow to the rear of the plane.  This makes the aircraft uncontrollable..  With keeping the "tail wing" at plane, or slightly +/- of the main wing, air will always being flowing over the "tail wing" providing control and stability of the aircraft.

Good Question.