Wind turbine with a vertical axis comprising: - a non-vertical arm; - a vertical rotating shaft having an axis of rotation coinciding with said vertical axis; - a braking device comprising a flap, said flap: • being mechanically connected by said non-vertical arm to said vertical rotating shaft; • being able to rotate about said vertical axis in a nominal position and to tilt about a non-horizontal tilting axis; • having a centre of gravity positioned outside the tilting axis, the said nominal position being such that a centrifugal force induced by the rotation of the said flap about the said vertical axis and exerted at the said centre of gravity is capable of creating a non-zero torque with respect to the said tilting axis in this nominal position, - the braking device further comprising a torque limiter having a predetermined release torque, a fixed part and a movable part with respect to the non-vertical arm; - the flap being mechanically connected to said movable part of said torque limiter; - said mobile part of the torque limiter being capable of allowing the flap to be tilted from the nominal position by a predetermined tilting angle about the tilting axis into a tilting position when a maximum speed of rotation of the flap about the vertical axis is reached, inducing a torque at the torque limiter which is greater than the release torque by the action of a centrifugal force acting on the centre of gravity of the flap in the nominal position; characterised in that - said torque limiter is capable of maintaining the flap in said tilting position for a speed of rotation of said flap about the vertical axis lower than said maximum speed of rotation. - a non-vertical arm; - a vertical rotating shaft having an axis of rotation coinciding with said vertical axis; - a braking device comprising a flap, said flap: • being mechanically connected by said non-vertical arm to said vertical rotating shaft; • being able to rotate about said vertical axis in a nominal position and to tilt about a non-horizontal tilting axis; • having a centre of gravity positioned outside the tilting axis, • being mechanically connected by said non-vertical arm to said vertical rotating shaft; • being able to rotate about said vertical axis in a nominal position and to tilt about a non-horizontal tilting axis; • having a centre of gravity positioned outside the tilting axis, - the braking device further comprising a torque limiter having a predetermined release torque, a fixed part and a movable part with respect to the non-vertical arm; - the flap being mechanically connected to said movable part of said torque limiter; - said mobile part of the torque limiter being capable of allowing the flap to be tilted from the nominal position by a predetermined tilting angle about the tilting axis into a tilting position when a maximum speed of rotation of the flap about the vertical axis is reached, inducing a torque at the torque limiter which is greater than the release torque by the action of a centrifugal force acting on the centre of gravity of the flap in the nominal position; characterised in that - said torque limiter is capable of maintaining the flap in said tilting position for a speed of rotation of said flap about the vertical axis lower than said maximum speed of rotation.