I had played with CG on my 4*40. Flew it for a couple years with the cg at the middle of the recommended range. Easy to fly and land.

I started to move the cg back a bit at a time. It became easier to land, landed slower, flew inverted with less up elevator.

New discovery, cool! If a little is good more is better right! I knew I had gone too far now. The plane got slower during the flare on landing. But now it would stall and snap and bang to the runway. If I was able to time the stall at the same time the main gear touched down, no problem. In summary, it would fly slower but the stall was harder/faster when it stalled.

With the CG more in the normal range, the stall was softer and it doesn't bang to the runway. I moved the cg forward to eliminate the hard stall and called it good.