Chiplight,
Please forgive my peevishness, I get testy when the phase of the Lu hits its peak! You are right, I skimmed your post then fired off a response, certainly too hard on you, I fear.
The sideslip in any rotorcraft induces a new freestream angle on the rotor, and thus causes the cyclic trim previously set to be significantly off. Typically, the aircraft sharply rolls away from the sideslip (positive dihedral) and usually pitches strongly although horizontal tail force changes due to sideslip can make this go either way. The retrim is significant, and when coupled with the low control power of a teetering rotor, can lead to large flapping angles. For many helicopters, the largest flapping angles are seen in low speed flight at forward CG. At this condition, the control margins can be most limited, and ripe for a sideslip to create an excessively large trim change.
The damping term is harder to explain, but the concept is that the aerodynamic flap forces on the blade are due to the changes in blade lift due to flap velocity. The response of the blade is softened by the flapping moment of inertia and the hinge offset. The aerodynamic forces in the flap direction are generally positive, where flap upward reduces the local angle of attack and thus reduces the thrust, creating a restoring force. For articulated systems, the blades see this force individually, while a teetering system experiences the flap across a pair of blades. I believe this has significantly higher inertia, and thus lower equivilent damping than a simple articulated blade. Also, the zero hinge offset teetering rotor has less natural damping as well. I have never seen it analytically shown, but typical rotor motions are much less damped than in articulated or "rigid" systems, so the blade motions are larger and require more control to stop them. As an exercise, just impose a rolling reversal on a helicopter, going from say 30 degrees bank in one direction to 30 in the other, fairly rapidly. Note the amount of cyclic required to stop the roll rate. For a Boelkow, there is almost no opposite cyclic required to stop the roll rate (high damping). For an articulated system, perhaps 1/2 inch of opposite cyclic is needed. For a teetering system, it takes a siginficant opposite cyclic to stop the roll, a measure of very weak damping. This means that in maneuvers where large maneuver rates need to be countered, teetering rotors require much more control input (more opposite flapping) to do so.