Can a helicopter trapped in a bubble generate lift?
I understand that it is a closed system, and should not. However, the equations for lift seem to rely on one simple thing: a pressure gradient. Conceptually I cannot reason out why this would be prohibited within a bubble.
Further, I imagine that the helicopter might be tethered to the bubble, and if lift is generated - that it would also lift the bubble. Perhaps even by adjusting the position of the tether, the lift force could be translated in to horizontal thrust, etc.
And...a slight extension of the same idea that I am curious about: if we made the bubble a slightly open system (perhaps by cutting a small opening on the bottom). Would it be possible to regulate the environment barrier between the inside and outside of the bubble, with the hope of maintaining proper atmosphere inside the bubble to continue generating lift?
I thought of this question while watching a movie that shows a helicopter not being able to climb past a certain elevation to rescue hikers on Mt. Everest. Like a divers "bell" helmet - could the helicopter have "pulled off" the rescue if it were trapped inside of a bubble that maintained atmospheric pressure for the spinning blades to act upon? That way it could climb, theoretically, to any elevation.