Clutch, driving system and unmanned helicopter

The invention relates to the field of unmanned aerial vehicles, and provides a clutch, a driving system and an unmanned helicopter. The clutch comprises a rotating seat connected with an output shaft of the engine, a plurality of blades distributed in the circumferential direction of the rotating seat are arranged on the rotating seat, and an airflow path driven by the blades is close to the blades in the axial direction of the rotating seat and away from the blades in the radial direction of the rotating seat; the gear ring is connected with each blade, and the gear ring is used for being in meshing transmission with a starter of the engine; the flail block is movably connected with the rotating base, the elastic piece is connected with the flail block, the flail block is used for being placed in a cup of the speed reducer, when the rotating base rotates to a preset rotating speed, the flail block moves in the radial direction of the rotating base and is connected with the cup, and the elastic piece is used