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Doesn't the DG's ball always indicate slip/yaw away from the direction of
rotation?
So, step on the ball, we were taught, and it works, stopping the turn.
Previously from Tom:
Not in an actual spin, where one wing is stalled, no. If the instrument is on the left side of the panel the ball will deflect to the left in a spin, no matter which direction you are spinning. If the instrument is on the right the ball will always deflect to the right.
Tom Gourley
I don't understand this last comment from Tom, although I have heard it from other sources. At first glance it implies that the center of rotation in a spin is exactly through the center of the instrument panel, which would seem very unlikely. If it were true the down wing would have to be moving backward. On further thought, though, the plane is tilted at a significant angle, tending to make the ball go to the low side, toward the direction of the spin. But if one assumes that the low (stalled) wing has a AOA of maybe 25 degrees or so it must be moving forward - hence the center of rotation has to be off the low wingtip, quite a distance from the aircraft centerline. In that case the centrifugal (centripetal for you purists) forces would push the ball to the outside of the rotation. The two forces then conflict with each other, so what does the ball do? I'll bet nothing reliable. Yaw rate is then the only useful indicator, available directly from the turn coordinator(more correctly called yaw rate indicator), or from the heading indicator.
Gary Casey
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