Abstract: A unison ring assembly comprises a backing plate, and a plurality of pocket-forming portions. The backing plate is formed as an annular disc, with the annular disc being planar in a radial plane of the unison ring assembly. The plurality of pocket-forming portions are equi-spaced circumferentially around the axis of the unison ring assembly, and each of the plurality of pocket-forming portions is attached to the backing plate to form a corresponding radially extending pocket.

Abstract: This invention relates to a blade assembly comprising: a hub which is rotatable about an axis; at least one blade having an aerofoil portion and a root, wherein the root is coupled to the hub using a primary retention device which prevents radial separation of the root and hub in normal use; and, a secondary retention device which comprises an annular catcher having a restriction through which the root portion cannot radially pass, the restriction being located radially outwardly and radially spaced from the root part during use.

Abstract: A unison ring assembly comprises a backing plate, and a plurality of pocket-forming portions. The backing plate is formed as an annular disc, with the annular disc being planar in a radial plane of the unison ring assembly. The plurality of pocket-forming portions are equi-spaced circumferentially around the axis of the unison ring assembly, and each of the plurality of pocket-forming portions is attached to the backing plate to form a corresponding radially extending pocket.

Abstract: A support ring for a rotary assembly such as a propeller assembly includes support cups for receiving blade roots of propeller blades. The support cups are interconnected by bridging structures. Each bridging structure includes bridging walls which extend radially from a bridging web. The bridging structures thus have a channel-shaped cross-section. The bridging walls have a scalloped configuration at their radially outer edges. As a result of this configuration, the neutral axes of the bridging structures are straight, so that the support ring behaves, in structural terms, as a polygon.

Abstract: This invention relates to a blade assembly comprising: a hub which is rotatable about an axis; at least one blade having an aerofoil portion and a root, wherein the root is coupled to the hub using a primary retention device which prevents radial separation of the root and hub in normal use; and, a secondary retention device which comprises an annular catcher having a restriction through which the root portion cannot radially pass, the restriction being located radially outwardly and radially spaced from the root part during use.