A composite duct panel assembly is provided. The composite duct panel assembly includes a composite duct panel having a curved cross-section in a circumferential direction and a width based on the panel including a portion of a circumference of an annular bypass duct. In one embodiment, at least two adjacent corners of the panel are greater than 90°. In one embodiment, the panel includes a circumferential flange along a circumferential edge and an axial flange along an axial edge, and the assembly further includes a corner bracket coupled to the panel, the circumferential flange, and the axial flange. The corner bracket includes a flange corner having an approximate 90° angle, the flange corner extending the axial flange and the circumferential flange to an intersection at a corner of the panel.