A hydraulic servo valve comprising: a servovalve body with first and second nozzles and a flapper provided therein, wherein said flapper is a bimorph piezoelectric flapper and comprises: a first layer of piezoelectric material and a second layer of piezoelectric material, and wherein said servovalve further comprises means for providing a positive voltage to one of said first and second layers (251, 252) and a negative voltage to the other of said first and second layers, and wherein said flapper extends longitudinally between a first end and a second end and wherein said second end of said flapper is positioned so as to be between said first and second nozzles so that said first layer faces said first nozzle and said second layer faces said second nozzle, and wherein said one of said first and second layers (251, 253) is made from a material that is configured to contract in a direction away from one of said nozzles and wherein the other of said first and second layers (251, 252) is made from a material that is configured to extend in the direction of the other of said nozzles when said voltages are applied to said flapper and characterized in that said first layer and said second layer have different thicknesses to each other in a state when no voltages are applied. a servovalve body with first and second nozzles and a flapper provided therein, wherein said flapper is a bimorph piezoelectric flapper and comprises: a first layer of piezoelectric material and a second layer of piezoelectric material, and wherein said servovalve further comprises means for providing a positive voltage to one of said first and second layers (251, 252) and a negative voltage to the other of said first and second layers, and wherein said flapper extends longitudinally between a first end and a second end and wherein said second end of said flapper is positioned so as to be between said first and second nozzles so that said first layer faces said first nozzle and said second layer faces said second nozzle, and wherein said one of said first and second layers (251, 253) is made from a material that is configured to contract in a direction away from one of said nozzles and wherein the other of said first and second layers (251, 252) is made from a material that is configured to extend in the direction of the other of said nozzles when said voltages are applied to said flapper and characterized in that said first layer and said second layer have different thicknesses to each other in a state when no voltages are applied. a first layer of piezoelectric material and a second layer of piezoelectric material, and wherein said servovalve further comprises means for providing a positive voltage to one of said first and second layers (251, 252) and a negative voltage to the other of said first and second layers, and wherein said flapper extends longitudinally between a first end and a second end and wherein said second end of said flapper is positioned so as to be between said first and second nozzles so that said first layer faces said first nozzle and said second layer faces said second nozzle, and wherein said one of said first and second layers (251, 253) is made from a material that is configured to contract in a direction away from one of said nozzles and wherein the other of said first and second layers (251, 252) is made from a material that is configured to extend in the direction of the other of said nozzles when said voltages are applied to said flapper and characterized in that said first layer and said second layer have different thicknesses to each other in a state when no voltages are applied.