In situ balancing mass(es) for aircraft powerplant

An apparatus for an aircraft powerplant, comprising:

• a rotating structure configured to rotate about an axis, the rotating structure including a first component, a second component, a first balancing mass and a spring element, wherein the first balancing mass is configured to rotationally balance the rotating structure about the axis;
• the first component comprising a plurality of first component teeth;
• the first balancing mass including a first mass ring, a first mass weight and a plurality of first mass teeth, the first mass ring extending circumferentially about the axis, the first mass weight connected to and located radially inboard of the first mass ring, an axial thickness of the first mass weight larger than an axial thickness of the first mass ring, the plurality of first mass teeth arranged circumferentially about the axis and projecting axially out from the first mass ring, and the plurality of first mass teeth meshed with the plurality of first component teeth;
• and
• the spring element configured to axially bias the first mass ring towards the first component and away from the second component.

An apparatus for an aircraft powerplant, comprising:

• a nut comprising a shoulder and a bore, the bore extending axially along an axis through the nut;
• a spacer disposed in the bore and comprising a plurality of spacer teeth;
• a first balancing mass disposed in the bore and including a first mass ring and a plurality of first mass teeth, the first mass ring extending circumferentially about the axis, the plurality of first mass teeth arranged circumferentially about the axis and projecting axially out from the first mass ring, and the plurality of first mass teeth meshed with the plurality of spacer teeth;
• a spring element disposed in the bore, the spring element configured to axially bias the first mass ring against the spacer;
• and
• a retainer disposed in the bore and mounted to the nut, wherein the spacer, the first balancing mass and the spring element are axially retained within the bore between the shoulder and the retainer.