I think Arm out the window has hit the nail on the head, and perhaps summarised previous posts succinctly. The UH-1H stab bar exihibts gyroscopic tendencies to adjust the rotor system sensitivity to both pilot and gust inputs. It is rigid.
Here is the summary: the Stab bar acts as a Gyro because it is rigid, the rotor aerodynamically precesses because it is not!
Does this satisfy? I think that is the gist of things thus far.
To Lu: I believe the device fitted to the Cheyeene was merely a pitch change mechanism thus mounted to help with the aerobatic capabilities of the aircraft and has nothing to do with gyroscopics. Nick will know for sure, but I believe this aircraft was the first aerobatic helicopter. Damn pretty too.
As for Mr Prouty, I have been a long time fan, and some what of a devotee to his explanations, but....and I will strap on the armour now....we are all entitled to our imperfections. I would find it thoroughly benefitial for his input on the topic at hand, but, I cannot subscribe to this particular statement of his. Lu, he is a pal of yours, can you encourage him on line?
Check the date on that publication Dave.....