Patent ID: 7959105

Claim:
An aircraft having a streamlined structure ( 10 ) pierced by an air flow duct ( 20 ) having an axis of symmetry (AX) contained in a plane of symmetry (P) perpendicular to a longitudinal axis (AL) of said aircraft, the aircraft possessing a shrouded rotor ( 1 ) having a plurality of blades ( 2 ) arranged in said air flow duct ( 20 ), wherein the periphery ( 21 ) of said air flow duct ( 20 ) is provided in succession along said axis of symmetry (AX) with a first lip ( 22 ), an intermediate portion ( 23 ), and then a second lip ( 24 ), said first lip ( 22 ) having a first front portion ( 22 ′) situated at the side of the duct that is closer to the front of the aircraft, and having a first rear portion ( 22 ″) situated at the side of the duct that is closer to the rear end ( 50 ) of the aircraft, said second lip ( 24 ) being provided with a second front portion ( 24 ′) situated at the side of the duct that is closer to the front of the aircraft and with a second rear portion ( 24 ″) situated at the side of the duct that is closer to the rear end ( 50 ) of the aircraft, and said aircraft is fitted with blower means ( 40 ) for reducing the noise generated by the shrouded rotor and suitable for propelling compressed air towards a first injection zone ( 44 ) opening out into said first front portion ( 22 ′), and to a second injection zone ( 45 ) opening out to said second front portion ( 24 ′).