Originally Posted by
Ascend Charlie
It's relative to whether gravity is going from your head to your feet (+1g) or you are floating in space (0g) or hanging upside down by your ankles (-1g).
S&L inverted flight is only possible in a toy helicopter, as real ones don't have the capacity for negative collective pitch (apart from a couple of navy machines, and only to hold them on the heaving deck). And the fuselage is designed to hang under the rotor system, not stand inverted on it.
Toy helicopters can't do that either. RC helicopters can though.