To: HeliEng
On the Bell 212 and on the 412 the lift link is not on the centerline of the mast/transmission. If I remember correctly, it is located forward and left of center. When the pilot pulls collective the lift link transmits the aerodynamic lifting loads to the fuselage from the transmission. Because the lift link is not on center the pylon (mast) will move in a vector forward and to the left until it is over the lift link. This mast movement also causes the transmission to shift its’ positional relationship to the output of the combining gear box causing a shift in the centerline of drive. In extreme maneuvering conditions this shifting may cause a disconnect of the drive shaft if the drive shaft starts to whip.
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The Cat