Jose wrote:
They aren't 'gotten rid of' they are accelerated which causes them to
be spaced farther apart -- thus lowering the pressure.

Accelerating them gets rid of them in the sense I mean, but I suppose I
was sloppy there. In any case, to be accelerated, they need to go
somewhere. The standard explanation is that there is a longer path up
top. The reason there is a longer path is that the air is bent
downwards. If you bend plywood (concave down), the top sheet is
stretched and the bottom sheet is compressed. Same with the air.

There is a longer path along the top because the wing is convex up.


When the air is bent downwards, the air is accelerated downwards. This
causes downwash.

Not until after it passes the high point in the airfoil. Befor it
gets there,
it is accelerated upwards.

Air accelerated downwards by the wing requires (by
Newton) the wing to be accelerated upwards (counteracting in this case
the acceleration due to gravity). It does so in a manner that also fits
Bernoulli's equations.

When the air reaches the trailing edge it is back to where it started.
But in the meantime air above it has begun to flow down. After the
wing has passed the momentum of _that_ downflow carries the air
down past the altitude of the wing. But that is after the wing has
passed. The downflow is -art of what happens as the air in the wake
of the airplane is restored to equilibrium.


The lift is a result of the pressure difference between the lower and
upper surfaces of the wing. The downwash is the result of the momentum
of the air above the rarefied region created by the wing moving
downward.

And the pressure difference is sustained by the wing continually
imparting momentum (indirectly by creating the pressure differential) to
the air above the rarified region.

Regardless, the lift is a result of the pressure differential between
the upper and lower wing surfaces.


The downrushing air starts it s downwash above the wing and does
not pass the wing in the vertical direction until after he wing has
passed.

Matters not. It is another way to look at lift.

No, it is a way of looking at downrushing air that has never
contacted the wing.


[The downrushing air] is not really caused by lift (my mistake),
it is caused by the same phenomenum that causes lift.

Fair enough. What this says is that both ways of looking at it are
valid. Bernoulli is easier to calculate, Newton is easier to conceptualize.


No. That says that the downrushing air and lift are both caused by the
same phenomenum.

--

FF