An assembly that comprises a first part and a second part. The second part comprises a non-faying surface facing the base surface, a plurality of faying surfaces manifested at bosses that are shimmed if and as required, and a plurality of second through-holes. A width of each one of the plurality of bosses is equal to or greater than 2(r+T tan θ), where r is a maximum radial dimension of an outermost peripheral portion of a fastener in contact with the first part or the second part, T is the distance from the point of contact, between a fastener and the first part or the second part, and a faying surface of a corresponding boss, and θ is an angle between a central axis of the corresponding second through-hole and an outermost load vector initiating at the point of contact between the fastener and the first part or the second part.

A flow path duct system for a propulsion system of an aircraft includes a base defining a flow surface. The base has an internal surface and an external surface. A plurality of perforations are formed through the base between the internal surface and the external surface. A plurality of supports define a plurality of cavities. The plurality of supports extend outwardly from the external surface of the of the base. One or more of the plurality of cavities are in fluid communication with the one or more of the plurality of perforations. A backing surface is secured to the plurality of supports. The plurality of supports are disposed between the base and the backing surface. The one or more of the plurality of cavities are in fluid communication with an internal volume defined by the internal surface of the base through the one or more of the plurality of perforations. The base, the plurality of supports, and the backing surface can be integrally formed together as a monolithic, load-bearing structure.

A flow path duct system for a propulsion system of an aircraft includes a base defining a flow surface. The base has an internal surface and an external surface. A plurality of perforations are formed through the base between the internal surface and the external surface. A plurality of supports define a plurality of cavities. The plurality of supports extend outwardly from the external surface of the of the base. One or more of the plurality of cavities are in fluid communication with the one or more of the plurality of perforations. A backing surface is secured to the plurality of supports. The plurality of supports are disposed between the base and the backing surface. The one or more of the plurality of cavities are in fluid communication with an internal volume defined by the internal surface of the base through the one or more of the plurality of perforations. The base, the plurality of supports, and the backing surface can be integrally formed together as a monolithic, load-bearing structure.

A quadrotor UAV including ruggedized, integral-battery, load-bearing body, two arms on the load-bearing body, each arm having two rotors, a control module mounted on the load-bearing body, a payload module mounted on the control module, and skids configured as landing gear. The two arms are replaceable with arms having wheels for ground vehicle use, with arms having floats and props for water-surface use, and with arms having pitch-controlled props for underwater use. The control module is configured to operate as an unmanned aerial vehicle, an unmanned ground vehicle, an unmanned (water) surface vehicle, and an unmanned underwater vehicle, depending on the type of arms that are attached.

A quadrotor UAV including ruggedized, integral-battery, load-bearing body, two arms on the load-bearing body, each arm having two rotors, a control module mounted on the load-bearing body, a payload module mounted on the control module, and skids configured as landing gear. The two arms are replaceable with arms having wheels for ground vehicle use, with arms having floats and props for water-surface use, and with arms having pitch-controlled props for underwater use. The control module is configured to operate as an unmanned aerial vehicle, an unmanned ground vehicle, an unmanned (water) surface vehicle, and an unmanned underwater vehicle, depending on the type of arms that are attached.

The invention relates to the rating (S) of a propulsion unit (2) comprising a main engine (3) providing main thrust assisted by an auxiliary engine (4) providing auxiliary thrust, according to the following steps: (i) determining (S1) a distribution between the main thrust and the auxiliary thrust so as to obtain the takeoff thrust of the propulsion unit, the auxiliary thrust making a 5% to 65% contribution to the takeoff thrust, (ii) depending on the distribution determined for the takeoff condition, determining (S2) distribution between the main thrust and the auxiliary thrust so its to obtain the top of climb thrust of the propulsion unit, the auxiliary thrust making at most 70% contribution to the top of climb thrust, and (iii) rating (S3) the propulsion unit (2) in such a way that the main thrust of the main engine (3) determined fir the takeoff condition corresponds to the maximum thrust likely to be achieved by the main engine (3).

The invention relates to the rating (S) of a propulsion unit (2) comprising a main engine (3) providing main thrust assisted by an auxiliary engine (4) providing auxiliary thrust, according to the following steps: (i) determining (S1) a distribution between the main thrust and the auxiliary thrust so as to obtain the takeoff thrust of the propulsion unit, the auxiliary thrust making a 5% to 65% contribution to the takeoff thrust, (ii) depending on the distribution determined for the takeoff condition, determining (S2) distribution between the main thrust and the auxiliary thrust so its to obtain the top of climb thrust of the propulsion unit, the auxiliary thrust making at most 70% contribution to the top of climb thrust, and (iii) rating (S3) the propulsion unit (2) in such a way that the main thrust of the main engine (3) determined fir the takeoff condition corresponds to the maximum thrust likely to be achieved by the main engine (3).

An aircraft having a fuselage, an aircraft body, at least one aircraft engine system and a feature. The fuselage defining a longitudinal centerline. The at least one aircraft engine system defining an axial centerline. The at least one aircraft engine system having a nacelle and at least one rotatable propeller. The at least one rotatable propeller having a free end that is spaced radially outward from the nacelle with respect to the axial centerline. The feature shaped to alter a flow of air between the aircraft body and the at least one rotatable propeller. The feature having a continuous rounded contour when viewed along a vertical plane normal to the longitudinal centerline and intersecting the feature.

A turbine system that harnesses energy from natural atmospheric wind and water currents for power generation and storage in a power storage mode, and in a reverse switched operation, sources current to the turbine system from storage power to function in a propulsion mode to propel an associated structure (e.g., boat, aircraft).

An aviation turbine engine having at least one unducted rotary propeller having a plurality of blades, each blade including: a blade body made of composite material including fiber reinforcement densified by a matrix, the fiber reinforcement of the blade body presenting three-dimensional weaving, the body extending between a leading edge and a trailing edge, and a protective fitting for protecting the leading edge and made of composite material having fiber reinforcement densified by a matrix, the fitting being adhesively bonded onto the leading edge of the blade body, the fitting being formed from a dry fiber preform injection molded with a densifying resin, and a polyurethane film for providing protection against erosion covering the blade body and the fitting.