A loading mechanism for a variable cant angle morphing winglet is proposed in this paper. The mechanism provides a method of loading a morphing winglet with the simulated aerodynamic lift force by maintaining its application direction always orthogonal to the surface of the winglet throughout the range of motion. The loading mechanism is developed by type synthesis of four-bar linkages through enumeration of prismatic and revolute joints. The final design is a R-P-R-P four-bar linkage modified by merging the middle P-R joint together to form a planar joint named Shark-fin. The shape of Shark-fin is optimized to minimize its weight effect on the overall loading system. A half-scale prototype was built as a reference to address several implementation issues including the neutral loading condition. Afterwards, a full-size dynamic loading mechanism was successfully constructed and implemented to load test a full-size morphing winglet.