You have to keep in mind that both wings add up to total flying surface. If you remove one wing, then wing loading becomes a HUGE problem. Maybe to the point that the plane doesn't have enough available lift to fly. It most certainly would not fly well--bi planes have shorter wings than equivilent monoplanes, but the fact that there are two wings makes up for that in the lift department--it also, though, introduces a lot more drag since there is overall more surface area exposed to the incoming air (plus support struts, etc).