Adverse Yaw

Confusion of terms, maybe?

"Adverse yaw" is typically used to desribe the motion of the nose (if
left unchecked by rudder) when the stick is used to roll the aircraft.
Roll to the left, the nose swings to the right, the reuslt of
diffential lift/drag across the span resulting from deflected ailerons.

As for the lift/drag across the wing resulting from a turn, while it
will have some effect on yaw, I agree with your sense of this being the
opposite of what's taught and what's observed: stick against the turn
to prevent overbanking (for moderate to steep turns) and rudder into
the turn to trim the tail (which is far enough outside the circle
transcibed by the cg that it tends to put the aircraft in a slip).
Maybe the author is ascribing the effect of the vertical stab in a turn
to the lift/drag distribution? You see, if you slip in a shallow turn,
dihedral effect will roll you level, so you need stick into the turn.

I think someone suggested just keeping the string straight. Can't argue
with that.


Mike wrote:
In the July issue of Soaring a letter writer contends that, during a
steep stationary turn, the outside wing creates less drag than the
inside and adverse yaw is caused by: 1)The inside wing flying at a
greater angle of attack than the outside wing, therefore creating more
drag on the inside wing (refers to lift vector diagrams) and 2)Down
aileron on the inside wing needed to create equal lift with the outside
wing while flying at a lower speed. He concludes, "Of course, the
incresed drag of the lower wing, caused by both 1) and 2) above, is the
source of adverse yaw." With all this drag on the inside wing why
wouldn't the glider yaw to the inside of the turn instead of the
outside? This is counter to everything I've learned. What am I (or is
he) missing here?

Mike Fadden