A sound absorber for an engine of an aircraft, the sound absorber comprising: a base body having a bottom plate, a wall enclosing the bottom plate and an opening enabling entry of air into the base body; and a porous tongue having a fixed end connected to the wall and a free end; wherein the tongue is porous.

A compact muffler (40) for an engine exhaust system, which is particularly applicable for use with small, reciprocating piston two-stroke engines of the type used on unmanned aerial vehicles (UAVs). The compact muffler (40) comprises an exhaust gas flow path (67) between an inlet (61) and an outlet (63). The exhaust gas flow path (67) comprises a plurality of adjacent flow passages (65), wherein at least two of the adjacent flow passages (65) are fluidly connected in series to enable the flow of exhaust gas from one to the other along the flow path (67). The adjacent flow passages (65) are configured for fluid flow therealong in opposed directions. A bypass passage (70) is provided between the two adjacent flow passages (65) for further communication between the two flow passages and to promote an equalisation of fluid pressure within the two adjacent passages (65). A UAV having an internal combustion engine (31) fitted with an exhaust system comprising the compact muffler (40) is also disclosed.

[Object] To provide a supersonic aircraft and a method of reducing sonic booms, by which sonic booms due to engine exhaust can be reduced. [Solving Means] A supersonic aircraft includes: a pair of engine nacelles 12R, 12L mounted on a fuselage 11 of an airframe 10; fins 13R, 13L as a pair of shielding plates that inhibits engine exhaust 15 discharged from jet engines (not shown) accommodated in the engine nacelles 12R, 12L from wrapping downward around the airframe 10; and a pair of horizontal tails 14R, 14L disposed behind the engine nacelles 12R, 12L. The fins 13R, 13L are disposed on the horizontal tails 14R, 14L so as to sandwich the engine exhaust 15, respectively.

A cascade type thrust reverser device for a turbomachine of an aircraft, comprising a thrust reverser cascade and a casing, the cascade including first cavities, and the casing comprising an opening defining a housing wherein said cascade can be inserted in a first direction, and the casing and said cascade being in relative translation with respect to one another in the first direction between a first position of the device in which the cascade is entirely positioned in the housing and a second position of the device in which said cascade is at least partially outside said housing. The casing comprises an acoustic treatment panel including second cavities extending in a second plane parallel to the first plane, each first cavity facing a second cavity when the device is in the first position to form an acoustic treatment cell.

A cascade for a thrust reverser device intended to be mounted on a turbomachine of an aircraft, the cascade including first partitions extending in a first direction, seconds partitions extending in a second direction orthogonal to the first direction, the second partitions extending in a third direction secant to a plane comprising first and second directions between a first and a second end. Each second partition forms, with reference planes parallel to the second direction and to the third direction, a plurality of different angles at positions distinct from the height of the second partitions separating the first end from the second end of the second partitions, each angle being formed between a reference plane and the tangent to the second partition taken at the intersection between said corresponding reference plane and the second partition at the position of the height of the corresponding second partition.

A foil, such as an aerofoil, having a leading edge and a trailing edge, of which at least a portion of one or both of the leading edge and trailing edge has a serrated profile comprising a plurality of adjoining teeth, each tooth having a tip point that represents a local maximum chord-wise extent of the tooth and, on each side span-wise of the tip point, a root point that represents a local minimum chord-wise extent of the tooth and at which the tooth adjoins a respective adjacent tooth, wherein the tooth edge profile varies with an ogee-like curve between tip point and root point such that the tooth is sharper in the neighbourhood of the tip point and in the neighbourhood of the root point than at locations in between.

A muffler (40) devised particularly for use with an engine of the type used on unmanned aerial vehicles (UAVs), and a UAV (10) having an engine (30) fitted with the muffler (40). The muffler (40) comprises a body (51) having an interior chamber (60). The muffler body (51) has a first end section (53) and a second end section (55). The first end section (51) is adapted for mounting onto the engine (31) by way of a first mount (81), with the interior chamber (60) in communication with an exhaust outlet of the engine (31) to receive exhaust flow therefrom. The second end section (53) is adapted to be mounted by way of a second mount (82) in a manner resisting movement with respect to the engine (31). In one arrangement, the second mount (82) is configured to yieldingly resist movement with respect to the engine (30). In another arrangement, the second mount (82) is configured to mount the second end section (55) under a preload resisting movement of the second end section with respect to the engine (30).

This present disclosure relates generally to propulsion systems and, more particularly, to adaptive ducted fan propulsion systems for use with aircraft such as unmanned aerial vehicles. Embodiments of ADF systems in accordance with the present disclosure feature automatic, fast operation, increase the intake section of the air mass fed to a propeller, and can increase thrust by 35%-40% as compared to existing ducted fans.

Provided is a supersonic aircraft including: a shield that shields an engine exhaust flow discharged from a jet engine accommodated in an engine nacelle mounted on a fuselage of the aircraft to thereby reduce sonic booms due to the engine exhaust flow; and an exhaust nozzle that is provided in an exhaust port of the engine nacelle and that generates a sound source for high-frequency components at a position at which the shield is capable of shielding the high-frequency components of the engine exhaust flow, to thereby reduce jet noise having the high-frequency components, and promotes mixing of the engine exhaust flow that generates low-frequency noise components with an external air flow to thereby reduce jet noise having the low-frequency components.

A method for manufacturing a composite panel is described. The method includes producing a first wall, a second wall, a third wall and a fourth wall from composite materials including an oxide matrix and long oxide fibres; from the first and second walls, producing a cellular core including a plurality of cells, each cell including a first end and an opposing second end, covering the first and second ends of the cells of the cellular core with the third wall and the fourth wall, respectively, so as to close the ends of said cells.