At 5 inches it is a little unstable but still takes a touch of down when inverted. When landing with low fuel state it will hunt in pitch. So it helps to go to low rates and disable flaperons when landing. No problem with flying but it is more sensitive in roll and pitch. It seems to fly as well at 4.75 but lands easier. It seems to me that I was about 4.5 inches before it would do power off flat spins and knife edge spins.