Thanks for the replies folks.
Its easy to see why you would not get pendular action easily on an aircraft that has a system that compensates for it , but looking at the replies it seems that the aircraft ( Chinook ) is prone to it like any other helicopter just its not as pronounced.
Nick , the rest of your reply seems to be missing ??
Agaricus bisporus, the importance of pendular action with out a load is basically to expose the fact that the helicopter is supported by the rotorhead and with some ( lets say exaggerated or sloppy ) control inputs , the helicopter will swing.
For example: from a hover - if you push forward on the cyclic till the aircraft begins to move forward then neutralise the cyclic, the helo will pitch down, move forward then level then would slightly nose up.
IF you then moved the cyclic back then neutralise the cyclic , the aircraft will pitch nose up, move back and then begin to move back.
This swinging action ( pendular action ) is basically demonstrating the forces in place because the AC is suspended from a point & is free to move like so.
Think of a rock suspended from a piece of string - pull the rock 90 degrees to where you are holding the string and let go of the rock and it swings back and forth.
If this pendular action did not excist then the aircraft would simply move forward, backward & sideways like it was on rails without all 6 axis coming into play.
This can be compounded when the AC is carrying an external load & again can grossly exaggerate/highlight the pendular action.
So control inputs are generally controlled & deliberate.
Thanks again all for your replies & if I am missing something or on the right/wrong track , let me know ..... I am always on a learning curve.
HF