Titan Strange 2nd humming sound

[zorka]

Hi,

I have been flying my new Titan hyper raptor for over 70 flights now from building it. I have noticed since around the 55+ flight besides the normal blades/engine sound I started getting a second humming sound which seems to come from the tail rotor or belt while hovering and flwd flying. I had rotor belt come loose a copule of times way in the past and tightened to specs per manual but this addditional strange humming sound was not there during the first 50 flights. BTW I use a governor and my set Head speed is around 1950 / 2000 RPMs and sound is apparent when full head speed is achieved.

Any ideas what it could be and solution?

Thx for the help

[capebob]

Check your tail rotor assembly. The retaining pin that secures the tail pulley to the tail rotor shaft may be coming out.

Bob

[zorka]

Found that the 4 bearings on the tail grips where damaged. These created play so one blade would have slight movement making the blades unbalanced. This caused the loud buzzing sound on the tail. All fixed now. Thx