Abstract: An empennage (1.1) of a helicopter comprising a ducted counter-torque device with a multi-blade rotor (4) of rotor blades (3) and optional vertical tail fins (1.2). Flow-straightening stators (5) of stationary vanes are disposed substantially in a star configuration parallel to the rotor plane downstream from the rotor (4). A shroud (2.1) of the ducted counter-torque device is sheathed with a composite structure of an outer erosion protecting surface layer (7.1, 8.1) made of a hard plastic or a plastic composite material, and at least one succeeding layer (7.2, 8.2) of an elastomeric damping material.

Abstract: An air vehicle, particularly a helicopter, includes a slip protecting and gas sealing composite floor inside a fuselage. The slip protecting and gas sealing composite floor is built up of a profiled elastomer layer provided at its bottom side with a cross-linking agent, n-layers of a further component or a variety of different components and partially thermosetting resin covered by a profiled elastomer layer, a honey comb layer and lower n-layers of the further component or variety of different components and partially thermosetting resin, the honey comb layer being sandwiched between the n-layers and the lower n-layers.

Abstract: An empennage (1.1) of a helicopter comprising a ducted counter-torque device with a multi-blade rotor (4) of rotor blades (3) and optional vertical tail fins (1.2). Flow-straightening stators (5) of stationary vanes are disposed substantially in a star configuration parallel to the rotor plane downstream from the rotor (4). A shroud (2.1) of the ducted counter-torque device is sheathed with a composite structure of an outer erosion protecting surface layer (7.1, 8.1) made of a hard plastic or a plastic composite material, and at least one succeeding layer (7.2, 8.2) of an elastomeric damping material.