Abstract: An aircraft door arrangement includes a door, a door seal, and a door opening. The door opening has an opening edge adjoining the door opening and extending into the aircraft fuselage, at which a seal seat is arranged, which can be brought into flush contact with the door seal. A hollow space, partially covered by the edge region of the door, is formed by the door seal, the seal seat, and the opening edge. A gap (located between the door and the door opening when the aircraft door is closed) is connected with the hollow space. A sound reducing profile is arranged at the opening edge in the hollow space, and it includes a sound reflecting surface oriented oblique with respect to a surface of the door, which is adjacent to the gap. The sound reflecting surface at least partially follows the course of the gap.

Abstract: An air conduction part for conducting a compressible medium, which part has a cross section through which the medium passes in a flow direction of the medium when the air conduction part is used, which flow direction approximately corresponds to a longitudinal axis of the air conduction part, the air conduction part including at least one wall arrangement that laterally defines the cross section of the air conduction part and conducts the medium. The wall arrangement are provided with at least one shell and with at least one damping device that removes sound energy from the medium, and the shell and the damping device are integrally interconnected so that, with a justifiable amount of outlay, the resulting air conduction parts effectively damp sound and the transport direction of the medium and/or the cross section of the air conduction part may change.

Abstract: An aircraft door arrangement includes a door, a door seal, and a door opening. The door opening has an opening edge adjoining the door opening and extending into the aircraft fuselage, at which a seal seat is arranged, which can be brought into flush contact with the door seal. A hollow space, partially covered by the edge region of the door, is formed by the door seal, the seal seat, and the opening edge. A gap (located between the door and the door opening when the aircraft door is closed) is connected with the hollow space. A sound reducing profile is arranged at the opening edge in the hollow space, and it includes a sound reflecting surface oriented oblique with respect to a surface of the door, which is adjacent to the gap. The sound reflecting surface at least partially follows the course of the gap.

Abstract: An air conduction part for conducting a compressible medium, which part has a cross section through which the medium passes in a flow direction of the medium when the air conduction part is used, which flow direction approximately corresponds to a longitudinal axis of the air conduction part, the air conduction part including at least one wall arrangement that laterally defines the cross section of the air conduction part and conducts the medium. The wall arrangement are provided with at least one shell and with at least one damping device that removes sound energy from the medium, and the shell and the damping device are integrally interconnected so that, with a justifiable amount of outlay, the resulting air conduction parts effectively damp sound and the transport direction of the medium and/or the cross section of the air conduction part may change.

Abstract: A silencer for an auxiliary power unit of an aircraft includes an inlet, an outlet, a housing, and a flow channel of a porous material, arranged in the housing. Between the housing and the flow channel an intermediate space is created, which space is divided by at least one outer partition into outer cells arranged around the flow channel. A central body includes a casing that is permeable to gas at least in some regions and that is arranged in the interior of the silencer. The central body includes inner partitions dividing the central body into inner cells. The resonance frequency of the inner cells corresponds to the natural frequency of the first radial mode in a channel formed between the central body and the inner surface of the inlet. In this manner particularly good sound attenuation is achieved with a compact installation space of a silencer.

Abstract: A silencer for an auxiliary power unit of an aircraft comprises an inlet, an outlet, a housing and a flow channel with a porous wall material that is arranged in the housing. An intermediate space is formed between the housing and the flow channel and divided into outer cells that are arranged around the flow channel by means of one or more partitions. This makes it possible to realize a very compact silencer with very good sound insulation properties. The sound dampening can be additionally improved by dividing the outer cells into outer regions and inner regions, by adapting the shape of the silencer to a tail section of an aircraft and by arranging an annular channel on the outlet.

Abstract: The invention relates to an air inlet for a vehicle comprising an opening with an opening contour in an outer skin of the vehicle; at least one bottom element; one or several walls between the opening contour and the bottom element; and an air guide channel with a longitudinal axis, wherein the bottom element extends from the outer skin of the vehicle to an interior region of the vehicle underneath a border edge of the opening, and the air guide channel adjoins from between the bottom element and the border edge, wherein at least one transition region between the opening contour and the walls at least in some regions comprises an essentially convex-shaped profile that essentially extends parallel to the air guide channel. The air inlet according to the invention is in a position to remove air from a flow boundary layer and to provide said air to air-consuming systems.

Abstract: A silencer for an auxiliary power unit of an aircraft comprises an inlet, an outlet, a housing and a flow channel with a porous wall material that is arranged in the housing. An intermediate space is formed between the housing and the flow channel and divided into outer cells that are arranged around the flow channel by means of one or more partitions. This makes it possible to realize a very compact silencer with very good sound insulation properties. The sound dampening can be additionally improved by dividing the outer cells into outer regions and inner regions, by adapting the shape of the silencer to a tail section of an aircraft and by arranging an annular channel on the outlet.

Abstract: The invention relates to an air inlet for a vehicle comprising an opening with an opening contour in an outer skin of the vehicle; at least one bottom element; one or several walls between the opening contour and the bottom element; and an air guide channel with a longitudinal axis, wherein the bottom element extends from the outer skin of the vehicle to an interior region of the vehicle underneath a border edge of the opening, and the air guide channel adjoins from between the bottom element and the border edge, wherein at least one transition region between the opening contour and the walls at least in some regions comprises an essentially convex-shaped profile that essentially extends parallel to the air guide channel. The air inlet according to the invention is in a position to remove air from a flow boundary layer and to provide said air to air-consuming systems.