A method of making a composite skin for a wing of a tiltrotor aircraft, comprising: providing a first skin in a mold, the first skin having a periphery defined by a forward edge, an aft edge, and outboard ends, wherein the first skin comprises a pre-cured laminate; providing a plurality of honeycomb panels having an array of large cells onto the first skin, each cell having a width of at least 1 cm; selectively positioning the plurality of honeycomb panels along the longitudinal axis of the first skin to form a honeycomb core having an outer perimeter within the periphery of the first skin; positioning a plurality of filler members between the plurality of honeycomb panels and positioning a plurality of filler members on outboard ends of the honeycomb core, wherein each of the filler members is butt jointed to the respective adjacent honeycomb panel; positioning a second skin onto the honeycomb core, the second skin having an outer perimeter within the periphery of the first skin, the outer perimeter (211p, 207p) of the second skin and the honeycomb core defined by a forward edge (211a, 207a), an aft edge (211b, 207b), and outboard edges (211c, 211d, 207c, 207d), wherein the second skin comprises a pre-cured laminate; positioning a plurality of joint members on the first skin, honeycomb core, and the second skin to form a joint system for a composite skin, each of the plurality of joint members is a composite material and includes a first flange, a second flange, and a support member disposed between the first flange and the second flange, the support member includes a first side and a second side, the first flange is a lower flange that extends laterally from the first side of the support member and the second flange is an upper flange that extends laterally from the second side to form generally a "Z" shape, the upper flange includes an attachment surface that overlaps a portion of the second skin and attaches thereto, the lower flange includes an attachment surface that overlaps a portion of the first skin and attaches thereto, the plurality of joint members provides a load path from the first skin(201 to the second skin; curing an adhesive to create a bond between the first skin, the honeycomb core, and the second skin to form a composite skin; and curing the plurality of joint members together with the composite skin to co-bond the composite joint members to the first and second skins (201, 211); wherein the selectively positioning of the plurality of honeycomb panels provides a selected stiffness for the wing of the tiltrotor aircraft. providing a first skin in a mold, the first skin having a periphery defined by a forward edge, an aft edge, and outboard ends, wherein the first skin comprises a pre-cured laminate; providing a plurality of honeycomb panels having an array of large cells onto the first skin, each cell having a width of at least 1 cm; selectively positioning the plurality of honeycomb panels along the longitudinal axis of the first skin to form a honeycomb core having an outer perimeter within the periphery of the first skin; positioning a plurality of filler members between the plurality of honeycomb panels and positioning a plurality of filler members on outboard ends of the honeycomb core, wherein each of the filler members is butt jointed to the respective adjacent honeycomb panel; positioning a second skin onto the honeycomb core, the second skin having an outer perimeter within the periphery of the first skin, the outer perimeter (211p, 207p) of the second skin and the honeycomb core defined by a forward edge (211a, 207a), an aft edge (211b, 207b), and outboard edges (211c, 211d, 207c, 207d), wherein the second skin comprises a pre-cured laminate; positioning a plurality of joint members on the first skin, honeycomb core, and the second skin to form a joint system for a composite skin, each of the plurality of joint members is a composite material and includes a first flange, a second flange, and a support member disposed between the first flange and the second flange, the support member includes a first side and a second side, the first flange is a lower flange that extends laterally from the first side of the support member and the second flange is an upper flange that extends laterally from the second side to form generally a "Z" shape, the upper flange includes an attachment surface that overlaps a portion of the second skin and attaches thereto, the lower flange includes an attachment surface that overlaps a portion of the first skin and attaches thereto, the plurality of joint members provides a load path from the first skin(201 to the second skin; curing an adhesive to create a bond between the first skin, the honeycomb core, and the second skin to form a composite skin; and curing the plurality of joint members together with the composite skin to co-bond the composite joint members to the first and second skins (201, 211); wherein the selectively positioning of the plurality of honeycomb panels provides a selected stiffness for the wing of the tiltrotor aircraft.