Arguing over this is useless. If you want to know how lift is generated you need to buy yourself a bookshelf of engineering textbooks and mathematical texts to back them up. Unless you are willing to do that, accept that simplified theories contain inherent shortcomings.
Any theory that does not, at a minimum include discussion of the bound vortex or Γ ("Circulation") (a rotating cylinder is usually presented as a good example) is over-simplified in the eyes of any engineer in my opinion. You shouldn't distinguish between Bernoullian and Newtonian theories, instead you should understand the relationships between the two. That doesn't mean assigning a ratio of percentages (25/75 is utter crap, and to go off an a tangent: even if it were that simple, it would greatly vary with AOA).
What it all boils down to: Pilots (and mechanics) do well with simple theories and airplanes do not fall out of the sky because the captain believed in an ignorant over-simplification of lift-theory. Those simple theories are all that pilots need to fly the airplane. Most continue to fly well even after forgetting the theoretical details. Just try to realize that "it is complex and my knowledge only scratches the surface." Then you won't be ignorant of your ignorance.
Arguing over this indeed useless -since no one is going to change their understanding based on one post, but I will throw in my $.02 for the sake of interesting reading.
>>>we had a heated debate on whether airlplanes were held aloft by bernoulli's priniple, i.e. pressure differential (high pressure under the wing, low on top) or newtonian lift, i.e. wind striking the underside of the wing, pushing it upward.
Certainly, in the air or in the water, we look at pressure differentials to understand what makes 'lift' happen. The thing is, as Buzz stated in regards to the DC-3 t/o, we have infallible evidence of a downwash. The lightbulb will come on when you understand the theoretics of (including the previously mentioned bound vortex) what produces the downwash.
I'll give you a hint, the low pressure area above the textbook airfoil isn't there to act like vacuum cleaner: it doesn't "suck" the wing "up."
The pressure differentials induce the circulation, the circulation causes the downwash (but also the upwash), and the mass of air in the net downwash is related to the mass of the aircraft (action-->reaction)
Angle of attack affects this circulation by increasing the pressure differentials, and thus increasing AOA makes the circulation stronger. When the airfoil stalls (loss of laminar flow at the critical AOA), the circulation breaks down, the downwash is reduced, and CL
falls rapidly as AOA continues to increase. Without lift, gravity accelerates a/c downward.
Now there is at least one person who says the air does not circulate spanwise around the wings. He is right, each air molecules passes only passes the stagnation point once, but this discussion is taking place in a different reference frame and we are not concerned with the flow of a single molecule.
So in effect, you were probably still wrong in the eyes of the PhD -even though you argued Bernoulli.
Then again, everything I know could be wrong in the eyes of someone who knows more than I.
Mathematically, we toss around two or three equations regarding lift production, but in fact, the amount of Calculus involved in calculating lift beomes quite complex with page long equations involving intregrals et al.