A device for control of an angular position of turbine blades of a propeller device, wherein the turbine blades are rotatable about a rotational axis and are pivotally displaceable about their respective pivot axes, said device comprising: a) a set of two control blades connected with the turbine blades and pivotally displaceable about their respective pivot axes thereof when the propeller device is exposed to a flow of fluid; and b) a transmission unit comprising a main gear and a secondary gear which transmits pivotal displacement of the control blades to the turbine blades such that turbine blades could be pivoted in respect to their pivot axes by the control blades via said transmission unit, wherein pivoting of the turbine blades takes place simultaneously with pivoting of the control blades, and - each of the control blades are connected to a first end of a control blade axle, wherein the control blade axle comprises a second end which is directly connected to the main gear and wherein the main gear directly engages the secondary gear; - the arrangement of said control blades being such that an angle of attack of the turbine blades is set and maintained automatically by said control blades irrespective of direction of the fluid flow, characterized in that: - the pressure center of each of the turbine blades is located over the pivot axis thereof, and the pressure center of the control blades is offset from their pivot axes wherein said turbine blades and said control blades are rotatable about the same rotational axis within the same plane. a) a set of two control blades connected with the turbine blades and pivotally displaceable about their respective pivot axes thereof when the propeller device is exposed to a flow of fluid; and b) a transmission unit comprising a main gear and a secondary gear which transmits pivotal displacement of the control blades to the turbine blades such that turbine blades could be pivoted in respect to their pivot axes by the control blades via said transmission unit, wherein pivoting of the turbine blades takes place simultaneously with pivoting of the control blades, and - each of the control blades are connected to a first end of a control blade axle, wherein the control blade axle comprises a second end which is directly connected to the main gear and wherein the main gear directly engages the secondary gear; - the arrangement of said control blades being such that an angle of attack of the turbine blades is set and maintained automatically by said control blades irrespective of direction of the fluid flow, characterized in that: - the pressure center of each of the turbine blades is located over the pivot axis thereof, and the pressure center of the control blades is offset from their pivot axes wherein said turbine blades and said control blades are rotatable about the same rotational axis within the same plane. - each of the control blades are connected to a first end of a control blade axle, wherein the control blade axle comprises a second end which is directly connected to the main gear and wherein the main gear directly engages the secondary gear; - the arrangement of said control blades being such that an angle of attack of the turbine blades is set and maintained automatically by said control blades irrespective of direction of the fluid flow, characterized in that: - the pressure center of each of the turbine blades is located over the pivot axis thereof, and the pressure center of the control blades is offset from their pivot axes