"Matthew Jurotich" wrote

There is a co-ordination exercise called Dutch Roll. The idea is to
rapidly roll the plane from zero to +nn degress to -nn degrees without
stoping at zero then back to zero while keeping the nose fixed at a
point on the horizon. When doing this correctly are the rudder and
ailerons co-ordinated or opposite? Why?

From William Kershner's "The Flight Instructor's Manual"

"Have the student line up with a good reference on the horizon
and roll the airplane from bank to bank, keeping the nose pinned
on the reference. For instance, have the student start (with the
nose lined up with the reference) by using left aileron and left
rudder, as in starting a turn. Before the nose has a chance to
move he should use right rudder so that the point is held. Then
he applies right aileron and more right rudder to roll the airplane
to the right, stopping any turn tendency with opposite (left)
rudder, and so on.
Elevators are part of the exercise and the altitude should stay
within 100 ft of the starting value.
You can also use the coordination exercise at lower airspeeds
(you set the power and trim the airplane) so that the student
can see the effects of adverse yaw, particularly in slow flight.
Again, don't have long sessions of this exercise and be prepared
for some wild swingings of the nose when he first does the
maneuver (and maybe later, too).
And, for Pete's sake, don't call this maneuver a "Dutch roll."
Dutch roll, a stability and control term, is a condition of a
coupling of lateral-directional oscillations with the nose yawing
as the airplane rolls from bank to bank; the object here is to
keep the nose on the point."

Bob Moore
ATP CFI