The ornamental design for a helmetcover, as shown and described.
FIG. 1 is a top plan view of a helmet cover showing my new design;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof; and,
FIG. 5 is a side view thereof, the opposite side being a mirror image.
The broken dashed lines on the brim of the helmet cover shown in FIGS. 1 and FIGS. 3-5 represent thread stitching, and are part of the claimed design.
The broken lines shown in FIGS. 2-5 representing a portion of the helmet and accompanying straps are for illustrative purposes only and form no part of the claimed design.
The cross-hatch shading in FIGS. 1 and 3-5 is understood to repeat throughout the indicated area.