I am getting a little lost here. If you are trying
to say that an aircraft when flying moves relative
to the airmass it happens to be in you are right. The
direction in which the airmass is moving is unimportant
as far as the aircraft is concerned, as long as it
remains flyng. The concept of what happens when a pilot
has to change the movement of his glider from relative
to the air to releative to the ground because it is
about to become a wheeled vehicle with wings is not
that important. What is vital is that pilots are trained
how to change from being a vehicle moving relative
to the airmass to one moving relative to the ground.
As pilots, unlike the aircraft, we are more concerned
with our movement relative to the ground.
Do we really seek to change our direction through the
airmass? What we seek to achieve is changing our direction
relative to the ground, to align track and heading,
we don't really care a jot that our movement relative
to the airmass has changed (or not) until we try to
operate outside the limits of the aircraft, then we
care a lot. I suppose what I am trying to say is that
the procedure is a very human thing, a skill that requires
teaching, and not one which deep scientific analysis
will help as there are so many variables.

At 14:00 22 February 2005,
wrote:
As often happens, the discussion is digressing into
the particulars of
landing in a crosswind, and I couldn't be happier.
Watching pilots
wrangle through the explanation of why they do what
they do is
fascinating, especially since the inference chain gets
all kinds of
twisted as they work their way back up to the model.

The trick, I'm convinced, is to completely divorce
the slip/skid
alignment maneuvers from the maneuver required to establish
a track
down the runway. Once we've determined that there is
a crosswind, the
only way to establish a proper track is to change our
direction through
the airmass. The problem arises when pilots confuse
the alignment
maneuver with the turn. We've discovered this slick
maneuver where we
can turn base to final and initiate the slip all in
one motion. Which
leads to a false perception that we only turned 90
degrees, then used
the wing to compensate for crosswind. But we have in
fact changed our
direction by more than 90 degrees and inserted our
alignment slip early
on final. But whether your turn is coordinated throughout,
or slipped,
the means by which we change direction is exactly the
same. Remove the
slip, and you'll point upwind, put the slip back in
and you'll point
down the runway. The forces produced by the glider
remain balanced
throughout.

Maybe it is easier to conceptualize this if you simply
ignore the
direction the nose is pointing and think of it in terms
of the glider's
path through the air. Because in a side slip the nose
is pointing down
the runway, there is an illusion that the lowered wing
is dragging the
glider sideways, compensating for the 'force' of the
wind. But in a
side slip (as in a foward slip), the horizontal component
of lift is
exactly balanced by the force created by sideways motion
of the
fuselage. There is no extra force to compensate for
an external force.
Which is a good thing since there is no external force
from the wind.

That said, an unbalanced force is required to establish
a new direction
through the air that will produce a desired ground
track. And this is
only accomplished by turning. Whether the turn is slipped
or skidded or
coordinated is a matter of pilot choice. It is nonetheless
a turn since
the direction of the glider changes. When the new direction
is
achieved, the turn ceases. Whether this is accomplished
by rolling the
wings level or increasing beta to balance the wing
turning force is a
matter of pilot choice.