OK, show us your arithmetic.

First, do you agree that air is made of individual molecules separated
by a lot of space compared to the size of the molecules themselves?
Then do you accept that a wing is in freefall during all the (very brief
but very numerous) time in between molecular collisions? (If not, what
holds it up when it is not in contact with any air molecules?)

If so, then during the time it is in freefall, it acquires a downward
velocity. Small, no doubt, but nonzero. The next molecular impact
pushes it back up. On the average they will sum to a net zero vertical
motion. Is this the arithmetic you want to see?

The ground is stationary. How does the stationary ground impart
momentum to anything?

The ground is not stationary. Like the wing, the ground is jiggling
around in brownian motion. Such motion is greatly overwhelmed in
quantity by other things, but it is nonzero. Gravity pulls the ground
towards the airplane just as strongly as it pulls the airplane towards
the ground. This is the same effect as the one that gives high tides on
the side of the earth that is away from the moon.

Where does this pressure differential come from -

Bernouli effect.

That's the shortcut. Where does the Bernoulli effect come from - on a
molecular level? That's what I'm addressing. The Bernoulli effect is a
shortcut for doing the calculation in bulk (where it makes the most
sense if you want a numerical answer) but it all comes from molecular
collisions.

Its just not relevent to the
issue of lift, which is only part of the picture.

We disagree here. Both explanations are true as far as they go, but it
is important to see just how far they go (or don't go). The Beruoulli
effect does not explain, for example, how the earth ultimately supports
the aircraft, nor how the upwash starts (for example, suppose there were
a vertical column of vacuum separated from the air by a very strong
piece of cellophane. A wing travels through the vacuum and penetrates
this cellophane. The air behind the cellophane does not rise up to meet
the wing - it has no idea there's a wing coming. Once the wing has
entered the air, that rising motion will start, but why?

That's the question to which I am applying my molecular model.

Jose
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