In article ,
says...
However, I must once again take exception to
the notion that tilting the lift vector compensates for crosswind.
This is simply wrong. Draw some pictures to work your way through the
problem.

I claim tilting the wing helps me compensate for the crosswind. I
don't know what is happening to the lift vector, since the wind is now
coming at the wing at an angle, and the dihedral and aileron
deflections will cause the left and right wings to have a different
lift distributions.

snip

If the
airmass is moving with respect to the ground, you establish a desired
track across the ground by crabbing.

I agree in general, but for the specific case where track=heading, we
don't call it crabbing; for example, if you are flying directly into
the wind.

When I use a slip to compensate for a crosswind during a landing, I'm
not "crabbing" because my heading and my ground track are aligned.

The difficulty comes when we need to transition from the air to the
ground. The moment the wheels touch the ground, the wind becomes an
unbalanced force, and we need to make control inputs to deal with it.
There are two techniques. We know them both. But be clear, we
compensate for airmass movement using a crab, not a slip.

Perhaps this is where we are confusing each other. I say

Crab = ground track different from heading
Slip = fuselage not aligned with airflow

So, I can crab in coordinated flight or in a slip. All it takes to
have a crab is have track not equal to heading.

Transition
to the ground is achieved by momentarily crossing the controls. I
prefer to do this during the flair. Others choose to initiate that
process after turning base.

When using a slip on final to compensate for a crosswind, the controls
are crossed the whole distance, not momentarily. I'm sure you know
this, so maybe I didn't understand your statement correctly.

It's a matter of preference. I like my yaw
string straight and my airspeed indicator dependable when near the
ground. (Eric, note that your visual and aural cues become less
trustworthy when near the ground or when flying sideways.)

I do monitor my airspeed while on final, which remains accurate during
the slip (not all gliders are like this, of course). "Near the
ground", meaning a little before I flare, I don't monitor the yaw
string or the airspeed (regardless of slipping or flying coordinated),
but instead fly by attitude and how fast the ground is approaching.

Again, a
matter of choice. But let's get off this notion that a tilted wing
cancels out the effect of wind. It doesn't, at least, not while you
are in the air. To establish a track down the runway you are crabbing.

It's not crabbing if the heading and ground track are the same. It
won't be coordinated flight in a cross wind, but it's still not
crabbing.

To align the fuselage parallel with the rundway, you are slipping.

I can align the fuselage parallel to the runway easily while flying
coordinated (no slipping), but I will drift off the center line.

You
may initiate both simultaneously, but they are distinct actions and
serve very different purposes.

Crabbing isn't a flight maneuver, it's the result of flight maneuvers
and the wind; slipping is a flight maneuver which depends on the
pilot's inputs, and not the wind.


This is building block stuff, which is why I'm still beating it.

Ditto!

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Eric Greenwell
Richland, WA (USA)