Flap drive device and blades of rotary-wing aircraft

A flap drive device installed on a blade body of a rotorcraft, the flap drive device comprising:

• a drive module;
• a flap drive link arm arranged behind the drive module and extending by a length in a front-rear direction;
• and
• a flap module arranged behind the flap drive link arm and capable of performing a pitch movement around a rotation center axis,
• wherein the drive module comprises an actuator shaft capable of changing a position thereof in the front-rear direction,
• wherein the flap drive link arm comprises a front hinge connection portion provided at a front end of the flap drive link arm and a rear hinge connection portion provided at a rear end of the flap drive link arm,
• the front hinge connection portion is pivotably-connected to the actuator shaft to pivot about an axis,
• the rear hinge connection portion is pivotably-connected to the flap module;
• the flap module comprising:
• a flap body;
• a rotation center hinge segment at a front end of the flap body;
• and
• a flap pivot hinge segment at the front end of the flap body,
• wherein the rotation center hinge segment connects a rotorcraft blade to the flap body,
• the flap pivot hinge segment hinge-connects the rear hinge connection portion of the flap drive link arm to the flap body,
• the rotation center hinge segment has a first hinge axis on the rotation center axis of the flap module,
• the flap pivot hinge segment has a second hinge axis,
• the first hinge axis is at a position on a chord line of the flap body, the second hinge axis aligned with the first hinge axis on a line perpendicular to the chord line, and
• a center of the first hinge axis and a center of the second hinge axis are apart from each other by a distance,
• wherein when a position of the actuator shaft changes in the front-rear direction, the flap module performs the pitch movement around the rotation center axis.