Flight

[J.C.MacSwell]

Bernoulli's principle is not a law of physics like conservation of energy. Bernoulli's principle derives from conservation of energy assuming an inviscid fluid undergoing laminar flow at low Mach numbers.

 

The flow around an inverted wing is anything but inviscid or laminar. Conservation of energy does of course apply, but Bernoulli's principle is an improper expression of conservation of energy for inverted flight. In inverted flight, it is the bottom of the wing that does the bulk of work in diverting the airflow downward. Bernoulli's principle is approximately correct for normal subsonic flight when it is the upper surface of the wing that does most of the work in diverting the airflow downward.

 

Even for normal flight, Bernoulli's principle is to me but a hand wave: It begs the question as to why airflow is faster along the upper surface of the wing. By the time you get to a valid explanation for this effect (e.g., via the Coanda effect, the Kutta condition, onset of turbulence), you have already arrived at the fact that a wing diverts airflow downward.

 

I agree with what you are saying overall but generally it is when the wing is in stall that the lower part of the wing provides most of the lift. This is true whether the wing is inverted or not, and while a non symmetric airfoil will stall sooner when inverted there is no reason the top of the wing cannot provide the majority of the lift for inverted flight.