Simply rolling inverted gives you exactly -1g.
No you are not.
The aerofoil (or for what matters the entire airframe) doesn't know what's up and what's down as long as the entire contraption is flown straight and lever at constant speed (for relatively short distances the said planet can be considered flat). Drag might be different but that's already another story.
+ or - are mathematical conventions, depending upon the referencing system one's choose. Since weight is a "standard" force experienced by everything on earth, it has been chosen to be positive, perpendicular to the surface and directed to the centre. Wanna go zero-g or negative? Get high the push down sharply...
PZ
