A rotary actuator (2500, 2900) comprising: a first housing defining a first arcuate chamber including a first cavity, a first fluid port in fluid communication with the first cavity, and an open end; a rotor assembly rotatably journaled in said first housing and including a rotary output shaft and a first rotor arm extending radially outward from the rotary output shaft; an arcuate-shaped first piston disposed in said first housing for reciprocal movement in the first arcuate chamber through the open end, wherein a first seal, the first cavity, and the first piston define a first pressure chamber, and a first portion of the first piston contacts the first rotor arm; a central actuation assembly including a central mounting point formed in an external surface of the rotary output shaft, and and characterized by a radial recess formed in an external peripheral surface of the first housing proximal to the central mounting point of the rotor shaft (412, 2912), wherein said central mounting point is proximal to the longitudinal midpoint of the rotary output shaft (412, 2912); and an actuation arm extending through the radial recess and removably attached at a proximal end to the central mounting point, said actuation arm adapted at a distal end for attachment to an external mounting feature of a member to be actuated. a first housing defining a first arcuate chamber including a first cavity, a first fluid port in fluid communication with the first cavity, and an open end; a rotor assembly rotatably journaled in said first housing and including a rotary output shaft and a first rotor arm extending radially outward from the rotary output shaft; an arcuate-shaped first piston disposed in said first housing for reciprocal movement in the first arcuate chamber through the open end, wherein a first seal, the first cavity, and the first piston define a first pressure chamber, and a first portion of the first piston contacts the first rotor arm; a central actuation assembly including a central mounting point formed in an external surface of the rotary output shaft, and and characterized by a radial recess formed in an external peripheral surface of the first housing proximal to the central mounting point of the rotor shaft (412, 2912), wherein said central mounting point is proximal to the longitudinal midpoint of the rotary output shaft (412, 2912); and an actuation arm extending through the radial recess and removably attached at a proximal end to the central mounting point, said actuation arm adapted at a distal end for attachment to an external mounting feature of a member to be actuated. a central mounting point formed in an external surface of the rotary output shaft, and and characterized by a radial recess formed in an external peripheral surface of the first housing proximal to the central mounting point of the rotor shaft (412, 2912), wherein said central mounting point is proximal to the longitudinal midpoint of the rotary output shaft (412, 2912); and an actuation arm extending through the radial recess and removably attached at a proximal end to the central mounting point, said actuation arm adapted at a distal end for attachment to an external mounting feature of a member to be actuated.