Looks like I hit a nerve .
Not that I disrespect the work done in the past on figuring stability margins , etc..
My point is ----- in actual practice - hands on testing -we find that the C of G can be changed -a alot ---IF the wing loading is very low --and especially if the power loading is also increased.
The currently popular "3D " type models have many examples of this.
We have tried this many times .
The CG can be placed at say 25% and the model exhibits solid forward stability and for accurate aerobatics - this is desireable.
However -when we get into aerobatics which include tumbles and controlled flat spins etc., - the CG can move aft - and in very lightly loaded models - way aft.
In actual practice - back past 50% of the avg chord.
The nice stability is gone - but the model is still very flyable.
I said if the wing loading was low enough - the CG does not matter .
Absurd?
If the loading is ZERO- Theoretically- where would you put the cg?
Why?
Have you seen or worked with these super light aerobats?
If not - I would suggest you take a peek.