The ornamental design for a flywheellock, as shown and described.
FIG. 1 is a perspective view of a flywheel lock showing my new design;
FIG. 2 is a front view thereof, the back view being a mirror image of FIG. 2;
FIG. 3 is a side view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof; and,
FIG. 6 is a front view thereof in a condition of use thereof.
In FIG. 6, the broken lines showing of environmental structure for purposes of illustrating the flywheel lock in a condition of use. The broken lines and the structure they depict form no part of the claimed design.