Abstract: Monolithic acoustically-treated composite structures and methods for fabricating the same are provided. A monolithic acoustically-treated composite structure comprises an internal frame assembly comprising a unitary composite frame structure and at least one acoustic panel assembly. The unitary composite frame structure defines a shape of the monolithic acoustically-treated composite structure to be fabricated. A composite overlay covers the internal frame assembly. The method for fabricating the monolithic acoustically-treated composite structure comprises forming the unitary composite frame structure, including the at least one acoustic panel in the unitary composite frame structure, and covering the internal frame assembly with the composite overlay.

Abstract: An airfoil is provided for an aircraft such as a helicopter, wherein the airfoil can be folded to a stowed position and unfolded to an operational position, without requiring an adjustment of the control rod assembly which lies within the airfoil. The control rod assembly (50, FIG. 2) includes inboard and outboard control rods (60, 62) with adjacent ends lying below the main axis (86) about which the foldable airfoil parts pivot, with a linkage (64) connecting the control rods. The linkage includes a long first link (90, FIG. 5) pivotally connected at a first axis (92) to an end of the inboard control rod and a second link (96) pivotally connected at a second axis (102) to the first link and at a third axis (106) to the outboard control rod. The links are constructed so they overlap in the operational position of the horizontal stabilizer, with the first, second, and third axes lying substantially along a force line (70).