Abstract: An aircraft may have one or more electrically powered thrust-generating engines and a combustion engine forming part of a power generator system for powering the electric engine and/or recharging a battery system that powers the electric engine. An exhaust pipe leads via an interior space within the aircraft from the exhaust of the combustion engine, or other source of hot gases, to an exhaust outlet. The direction of the exhaust pipe at the outlet is transverse to the longitudinal axis of the aircraft. A fairing immediately upstream of the outlet has a trailing edge, for example with a sawtooth profile, which creates turbulence and/or chaotic airflow over and downstream of the outlet, and thus mixes the freestream air and the hot gases from inside the aircraft more efficiently.

Abstract: An auxetic bi-stable structure that comprises an auxetic curved shell movable between a first and a second stable position, and a rigid element. At least part of the surface of the auxetic curved shell is joined to the rigid element such that the curved shell is movable with respect to the rigid element between the first and second stable positions.

Abstract: A drain mast for draining liquids from an aircraft, comprising a tube that comprises an internal rim connected to the internal surface of the tube, the internal rim being located in a plane inclined with respect to the horizontal plane of the aircraft and having its lowest part located on the second end of the tube, an aperture for evacuating the liquid, the aperture being located at the lowest part of the internal rim and in the face of the tube facing the incoming airflow, the internal rim and the aperture being configured such that at the second end, the liquid is directed by gravity through the internal rim to the aperture and wherein, in use, the drained liquid flowing from the aperture is pushed by the incoming airflow to the atmosphere.

Abstract: A boundary layer suction system adapted to a surface exposed to the circulation of a fluid. The system comprises a portion of the surface, a bifurcation element for bifurcating a mass of fluid flowing along the front face of the surface, comprising an airfoil-shaped cross-section such that the fluid is bifurcated into a first and a second flow, a slot located on the portion of the surface and downstream of the leading edge of the bifurcation element, the slot communicating the front and the rear faces of the portion of the surface, and an arrangement to provide a pressure difference between the front and the rear faces of the surface around the slot, such that a suction of the boundary layer is performed through the slot by the pressure difference.

Abstract: An auxetic bi-stable structure that comprises an auxetic curved shell movable between a first and a second stable position, and a rigid element. At least part of the surface of the auxetic curved shell is joined to the rigid element such that the curved shell is movable with respect to the rigid element between the first and second stable positions.

Abstract: A drain mast for draining liquids from an aircraft, comprising a tube that comprises an internal rim connected to the internal surface of the tube, the internal rim being located in a plane inclined with respect to the horizontal plane of the aircraft and having its lowest part located on the second end of the tube, an aperture for evacuating the liquid, the aperture being located at the lowest part of the internal rim and in the face of the tube facing the incoming airflow, the internal rim and the aperture being configured such that at the second end, the liquid is directed by gravity through the internal rim to the aperture and wherein, in use, the drained liquid flowing from the aperture is pushed by the incoming airflow to the atmosphere.

Abstract: A drain mast for draining liquids from an aircraft. The drain mast comprises a tube and further comprises a pipe coupled to the inner longitudinal surface of the tube and configured such that the drained liquid flows from the tube to the pipe. The pipe has an inlet having its longitudinal axis configured to confront the coming airflow for allowing the inlet of the coming airflow into the pipe, and an outlet having its longitudinal axis inclined with respect to the longitudinal axis of the inlet and configured to discharge the airflow flowing through the pipe in a direction inclined with a component perpendicular to the fuselage of the aircraft.

Abstract: A boundary layer suction system adapted to a surface exposed to the circulation of a fluid. The system comprises a portion of the surface, a bifurcation element for bifurcating a mass of fluid flowing along the front face of the surface, comprising an airfoil-shaped cross-section such that the fluid is bifurcated into a first and a second flow, a slot located on the portion of the surface and upstream of the leading edge of the bifurcation element, the slot communicating the front and the rear faces of the portion of the surface, and an arrangement to provide a pressure difference between the front and the rear faces of the surface around the slot, such that a suction of the boundary layer is performed through the slot by the pressure difference.

Abstract: A drainage mast able to drain effectively the liquid contained in the compartment of an aircraft when the pressure within the compartment is lower than the outside pressure without using any pressure control active device and without causing any significant perturbation to the aerodynamic behavior of the aircraft. The drainage mast is configured with a cross section area decreasing from its entry section to the compartment to its outlet section and is disposed at an acute angle ? relative to the compartment in the airflow direction. The entry and outlet sections have two perpendicular symmetry axes of different length, the entry section is arranged with its longer axis of symmetry substantially parallel to the airflow direction. The drainage mast has a symmetrical configuration with respect to a plane substantially perpendicular to the fuselage envelope passing through the longer axis of symmetry of the entry section.

Abstract: A system and method for computing thermal boundary conditions from an unstructured computational fluid dynamics (CFD) simulation for a thermal simulation of a structural component are disclosed. The thermal boundary conditions include convective heat transfer coefficient (HTC) and reference temperature (Tref). In one embodiment, prism cells are formed to capture boundary layer substantially next to a wall of the structural component. Further, tetrahedral cells are formed to capture a diffused temperature layer substantially next to the formed last prism cell and in a direction normal to the wall. Furthermore, temperature of each of the prism cells is computed in the direction normal to the wall until a substantially first tetrahedral cell. In addition, the computed temperature of the prism cell that is substantially adjacent to the first tetrahedral cell is declared as the Tref. Also, the HTC is computed using the obtained Tref.

Abstract: A drainage mast able to drain effectively the liquid contained in the compartment of an aircraft when the pressure within the compartment is lower than the outside pressure without using any pressure control active device and without causing any significant perturbation to the aerodynamic behavior of the aircraft. The drainage mast is configured with a cross section area decreasing from its entry section to the compartment to its outlet section and is disposed at an acute angle ? relative to the compartment in the airflow direction. The entry and outlet sections have two perpendicular symmetry axes of different length, the entry section is arranged with its longer axis of symmetry substantially parallel to the airflow direction. The drainage mast has a symmetrical configuration with respect to a plane substantially perpendicular to the fuselage envelope passing through the longer axis of symmetry of the entry section.

Abstract: A system and method for computing thermal boundary conditions from an unstructured computational fluid dynamics (CFD) simulation for a thermal simulation of a structural component are disclosed. The thermal boundary conditions include convective heat transfer coefficient (HTC) and reference temperature (Tref). In one embodiment, prism cells are formed to capture boundary layer substantially next to a wall of the structural component. Further, tetrahedral cells are formed to capture a diffused temperature layer substantially next to the formed last prism cell and in a direction normal to the wall. Furthermore, temperature of each of the prism cells is computed in the direction normal to the wall until a substantially first tetrahedral cell. In addition, the computed temperature of the prism cell that is substantially adjacent to the first tetrahedral cell is declared as the Tref. Also, the HTC is computed using the obtained Tref.

Abstract: An auxiliary power unit intake duct for an aircraft, comprising an internal straight portion 1a, an internal first bend portion 1b and an internal second bend portion 1c, extending between an air inlet 2 and a plenum entry 3 of the auxiliary power unit, a plurality of acoustic guides vanes 4,5 located in the straight portion 1a of the intake duct 1, extending horizontally between opposite side portions of the straight portion 1a; and a plurality of curved aerodynamic guide vanes 6,7 located in the second bend portion 1c proximate to said plenum inlet 3, extending vertically between a top portion and a bottom portion of the second bend portion 1c, each of the curved aerodynamic guide vanes 6,7 being concentric with said bend curvature of the second bend portion 1c.