R44 Chugging
Has anyone out there experienced this in a R44 before;
A forward & aft movement of the main rotor mast which causes a rocking sensation in flight.
The severity of this rocking is largely dependent on the aircraft C of G loading and the abruptness of flight manoeuvres.
Rocking can get severe enough that pilot and passengers seriously believe that their life is about to end.
Worst case scenario is a complete loss of aircraft control. Recoverable situations may result in the bottom of the mast cowling contacting the front and rear aircraft panels sustaining damage to the roof panels and mast cowling.
The cause is unknown, however some theories are based around the change in chord length on the main rotor blades compared to the R44 Raven model, additionally the standard transmission mounts have been found to be made of a soft compound which may aggravate the problem. Low rotor head friction may also exacerbate this issue. Harder compound transmission mounts are available which, when fitted, along with a re-torque of the mast head improves the situation, however there is currently no complete solution to this phenomenon which the Robinson factory are aware of.
Please don’t remove this post Mr Moderator.