The ornamental design for a gliderswingarm, as shown and described.
FIG. 1 is a front perspective view of a glider swing arm showing my new design;
FIG. 2 is a front orthographic view thereof;
FIG. 3 is a rear orthographic view thereof;
FIG. 4 is a right side orthographic view thereof;
FIG. 5 is a left side orthographic view thereof;
FIG. 6 is a top plan side view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is an enlarged front perspective view thereof.
The broken lines shown in FIG. 8 are included for the purpose of illustrating the glider swing arm broken away only and form no part of the claimed design.