I thought I had discounted gyroscopic action in my post. Obviously I wasn't clear enough.
I am at a bit of a loss to understand how this materially affects the handling of a helicopter from a pilot's point of view if the effect would seem to be automatically compensated for by the normal pilot reactions when a deviation from altitude and course is detected.
I can see how this effect might have very meaningful consequences during inadvertant entry into IMC without an instrument rating and suitable panel.
It would be nice to hear how this seemingly counter intuitive nose down attitude in response to yaw/rudder input affects flight operations in a real life scenario. Are all rotary wing craft purposely designed to react this way so the pilot response is identical no matter which way the aircraft yaws?