The ornamental design for a propellerfan, as shown and described.
FIG. 1. is a front perspective view of the front, right, and bottom sides of a propeller fan showing an initial embodiment of our new design;
FIG. 2. is a front view thereof;
FIG. 3. is a rear view thereof;
FIG. 4. is a left side view thereof;
FIG. 5. is a right side view thereof;
FIG. 6. is a top plan view thereof;
FIG. 7. is a bottom view thereof; and,
FIG. 8. is an enlarged view at a part 8 of FIG. 1.
The broken lines shown represent unclaimed subject matter of the propeller fan and form no part of the claimed design. The dash-dot lines represent the boundary between the claimed design and unclaimed design.