Could this effect be a contributer, Vfrpilot:
The lateral thrust of the tail rotor makes us have to compensate with some bank angle in a hoverto keep from translating laterally. Typical helicopters with high tail rotors need about 3 degrees of bank in a hover to compensate. Using the French clockwise main rotor rotation convention, the side thrust of the fenestron requires about 5 degrees of right roll (and the concurrent right cyclic position) to balance, because the fenestron is low, on the roll axis of the aircraft. If the fenestron were significntly above the roll axis of the machine, the roll moment of the fenestron thrust would help reduce that bank angle to the more typical 3 degrees. In OGE hover, where the fan thrust is even higher, the roll is 6 or 6.5 degrees.
This larger roll angle creates the noticible right lateral stick motion that you see, Vfrpilot. Where you are used to some left stick in a typical helicopter, you see even more right stick in the Gazelle, and the diference is quite obvious.
We faced this issue when we layed out Comanche, and we decided that the 5 to 6 degrees of roll in a hover was OK. The Fly By Wire stick made it easy to hide any stick trim issues, of course.
[ 16 January 2002: Message edited by: Nick Lappos ]</p>