The discussion to-date has address the probable sources of nP vibration during high-speed flight, but little has been said about this vibration during translation.
Could this vibration be (partially) due to the horizontal stabilizer and its change of location in respect to the rotor's downwash?
Could it also be that the forward tilt of the rotor, has resulted in the axis of the tip path plane to not be concentric with the axis of the mast and this results in a oscillating dynamic load, since the hub acts as a knuckle joint, not a constant-velocity joint?
[ 19 January 2002: Message edited by: Dave Jackson ]</p>