Thanks for the explanation Ed.
However, what I really want to know is what CG makes the glider most efficient. You see, I've never flown an aircraft as stable as this. I'm used to most aircraft flying in whatever direction you point them. The Radian will constantly correct itself (if you let go of the sticks) to an optimal descending glide path. You can push the nose over and let go.. it will level off. If you pull up, it will stall, rapidly descend and level off.
I can change the descending glide path by using elevator trim. ie i can speed it up or slow down the descent rate (until it constantly porposes thru stall maneuvers).
If I adjust CG - i can maintain same glide path by re-trimming out the elevator. I would think with an aft CG - the horizontal stab and elevator would create more drag (because it is fighting from sinking). Same goes for a forward CG.
I would imagine a perfect CG would yield optimum lift/drag ratio..which, I would imaging is what you are looking for on a thermal duration glider. Right?
With that said.. what is the optimum CG for the Radian?