To: 212 Man
It seems that we were talking about two different things. You were addressing pylon rock and I was addressing loss of lift. However I beg to differ with you about it only happening while lifting heavy loads and moving at walking speed. As I had previously stated when lift is generated the soft mounts flex until the entire load is suspended on the lift link. Because the lift link is not centrally located the transmission will shift as allowed by the flex mounts. This will cause the pylon to move forward and to the left. When the helicopter starts to move forward it will reach the point where the 2 per rev will start. When moving up and down on the soft mounts the reaction of the transmission forcing down on the lift link will cause the pylon to move to the right and to the rear. When the transmission rises the lift link geometry will cause the pylon to move forward and to the left. This same situation will happen but to a different degree when maneuvering causing the pylon to move in an elliptical pattern. This condition does not exist on four blade Bell helicopters nor, does it happen on a Bell with a Nodamatic suspension system.
I would still like to have someone answer my question about what forces are involved in causing a 6-800 pound transmission and an 800 pound rotor system (214) bounce up and down in excess of 2”. How and where are these forces generated.
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The Cat