The ornamental design for a fuelcellpowerpack for drone, as shown and described.
1. Fuel cell power pack for drone
1.1 is a front perspective view of a fuel cell power pack for drone embodying our new design;
1.2 is a front elevation view thereof;
1.3 is a rear elevation view thereof;
1.4 is a left side elevation view thereof;
1.5 is a right side elevation view thereof;
1.6 is a top plan view thereof;
1.7 is a bottom plan view thereof; and
1.8 is a rear perspective view thereof.
Design 1: the materials are a metal, a synthetic resin and a non-metallic material; design 1 relates to a fuel cell power pack for a drone mounted to and detached from the drone; is for illustrative purposes only and form no part of the claimed designs.