A rotary wing aircraft that extends along an associated roll axis (R) between a nose region and an aft region and that comprises a fuselage with a front section and a rear section , the rotary wing aircraft comprising: a main rotor that is at least configured to provide lift in hover condition of the rotary wing aircraft , a shrouded duct that is arranged in the aft region and that forms an inner air duct , wherein the shrouded duct is formed to generate sideward thrust for main rotor anti-torque and downward thrust for pitch stability in forward flight condition of the rotary wing aircraft , and a propeller that is at least configured to propel the rotary wing aircraft in the forward flight condition; wherein the propeller comprises a predetermined number of propeller blades with associated blade tips which form a circular propeller disc in rotation of the propeller around an associated rotation axis , and wherein the propeller is rotatably mounted to the shrouded duct such that the circular propeller disc is at least essentially arranged inside of the inner air duct , wherein the shrouded duct comprises at least a first airfoil-shaped profile and a second airfoil-shaped profile which are formed with different angles of attack relative to the associated rotation axis of the propeller and arranged on diametrically opposed sides of the shrouded duct , wherein the shrouded duct further comprises at least a third airfoil-shaped profile and a fourth airfoil-shaped profile which are arranged on diametrically opposed sides of the shrouded duct respectively between the first and second airfoil-shaped profiles and connected via smooth transitions to the first and second airfoil-shaped profiles , and wherein the first and second airfoil-shaped profiles are configured to generate the sideward thrust and the third and fourth airfoil-shaped profiles are configured to generate the downward thrust . a main rotor that is at least configured to provide lift in hover condition of the rotary wing aircraft , a shrouded duct that is arranged in the aft region and that forms an inner air duct , wherein the shrouded duct is formed to generate sideward thrust for main rotor anti-torque and downward thrust for pitch stability in forward flight condition of the rotary wing aircraft , and a propeller that is at least configured to propel the rotary wing aircraft in the forward flight condition; wherein the propeller comprises a predetermined number of propeller blades with associated blade tips which form a circular propeller disc in rotation of the propeller around an associated rotation axis , and wherein the propeller is rotatably mounted to the shrouded duct such that the circular propeller disc is at least essentially arranged inside of the inner air duct , wherein the shrouded duct comprises at least a first airfoil-shaped profile and a second airfoil-shaped profile which are formed with different angles of attack relative to the associated rotation axis of the propeller and arranged on diametrically opposed sides of the shrouded duct , wherein the shrouded duct further comprises at least a third airfoil-shaped profile and a fourth airfoil-shaped profile which are arranged on diametrically opposed sides of the shrouded duct respectively between the first and second airfoil-shaped profiles and connected via smooth transitions to the first and second airfoil-shaped profiles , and wherein the first and second airfoil-shaped profiles are configured to generate the sideward thrust and the third and fourth airfoil-shaped profiles are configured to generate the downward thrust . <EOS>