A gas turbine engine, comprising: a fan system operative to generate a bypass flow; a bypass duct in fluid communication with the fan system and operative to transmit the bypass flow from the fan system, the bypass duct comprising an outer bypass flowpath wall and an inner bypass flowpath wall; a compressor system in fluid communication with the fan system; a combustion system in fluid communication with the compressor system; a turbine system in fluid communication with the combustion system and operative to discharge an engine core flow, wherein the turbine system includes a turbine system discharge portion operative to discharge the core flow; a discharge duct in fluid communication with the turbine system and the fan system, wherein the discharge duct is configured to receive the bypass flow and the core flow, and to discharge an exhaust flow formed of the bypass flow and the core flow; and means for varying a ratio of the bypass flow to the core flow in the discharge duct by translating between a first position yielding a maximum bypass exit flow area and a second position yielding a minimum bypass exit flow area, the bypass exit flow area defined between a downstream end of the means for varying and the outer bypass flowpath wall; the means for varying comprising a variable area bypass mixer configured to vary a ratio of the bypass flow to the core flow, wherein the variable area bypass mixer includes a translatable sled; the variable area bypass mixer being configured to translate the sled between the first position yielding the maximum bypass exit flow area of the bypass duct exposed to the discharge duct and the second position yielding the minimum bypass exit flow area of the bypass duct exposed to the discharge duct; wherein the sled forms at least a portion of an outer core flowpath wall; wherein the turbine system includes a discharge portion having an inner core flowpath wall; characterized in that the bypass mixer further includes an actuator coupled to the sled, the actuator being disposed in the bypass duct and being configured to translate the sled between the first position and the second position; and a forward portion of the actuator being mounted on a fixed portion of the inner bypass flowpath wall. a fan system operative to generate a bypass flow; a bypass duct in fluid communication with the fan system and operative to transmit the bypass flow from the fan system, the bypass duct comprising an outer bypass flowpath wall and an inner bypass flowpath wall; a compressor system in fluid communication with the fan system; a combustion system in fluid communication with the compressor system; a turbine system in fluid communication with the combustion system and operative to discharge an engine core flow, wherein the turbine system includes a turbine system discharge portion operative to discharge the core flow; a discharge duct in fluid communication with the turbine system and the fan system, wherein the discharge duct is configured to receive the bypass flow and the core flow, and to discharge an exhaust flow formed of the bypass flow and the core flow; and means for varying a ratio of the bypass flow to the core flow in the discharge duct by translating between a first position yielding a maximum bypass exit flow area and a second position yielding a minimum bypass exit flow area, the bypass exit flow area defined between a downstream end of the means for varying and the outer bypass flowpath wall; the means for varying comprising a variable area bypass mixer configured to vary a ratio of the bypass flow to the core flow, wherein the variable area bypass mixer includes a translatable sled; the variable area bypass mixer being configured to translate the sled between the first position yielding the maximum bypass exit flow area of the bypass duct exposed to the discharge duct and the second position yielding the minimum bypass exit flow area of the bypass duct exposed to the discharge duct; wherein the sled forms at least a portion of an outer core flowpath wall; wherein the turbine system includes a discharge portion having an inner core flowpath wall; characterized in that the bypass mixer further includes an actuator coupled to the sled, the actuator being disposed in the bypass duct and being configured to translate the sled between the first position and the second position; and a forward portion of the actuator being mounted on a fixed portion of the inner bypass flowpath wall.