Has anyone considered the human physiology aspect of this, and as such did FR come to the 18 degrees offset based on what felt "right" rather than any other design criteria. It cannot be contested that the offset is not a problem to pilots under normal circumstances.
It is some time since I flew a R22 but I remember that holding the cyclic with the left hand made control difficult. This is in marked contrast to my Enstrom which is often flown left handed with no difficulty, whilst adjusting mixture, radios etc. (Enstrom flown from left seat - no offset).
My point is , does the offset fit in with the natural movement of the shoulder and elbow joint of the right arm to make it feel right even though the disk is not moving in the same plane as the cyclic? Does the unique T bar control have any effect?
As we are keen on tests, get a protractor set up facing away from you. move your arm fore and aft not holding anything, resting on your knee, at 90 degrees to your body. Both joints must move. Then try moving it with 20 degrees offset and watch the joints. Which feels more natural?
Robinson don't rely on servos and electronics to nullify the offset. The pilots brain is trained to do it - until you try it left handed.
Could everybody be right?
FR may not like to admit that 18 degrees was arrived at by trial and error. That probably would not have convinced the FAA at the design stage.
Just a thought.