Full-speed trapezoidal flap fin

The invention belongs to the technical field of ship fin stabilizer devices, and particularly relates to a full-speed trapezoidal flap fin which comprises a main wing, a flap and a flap extension plate, the rear edge of the main wing and the front edge of the flap are hinged together through a flap shaft, and the main wing drives the front edge of the flap to have a rotational degree of freedom with a preset angle along the center line of the main wing fin shaft. The rear edge of the flap is connected with the front edge of the flap extension plate; the flap transmission mechanism drives the flap to rotate relative to the main wing along the flap shaft center line according to the same rotation direction as the main wing based on the rotation direction of the main wing around the main wing fin shaft center line. Compared with an existing ship fin stabilizer, the maximum thickness of the section of the trapezoidal flap fin is reduced by 20%-35%, the fluid pressure difference resistance of the fin is reduced du