An auxiliary power unit for an aircraft includes a rotary intermittent internal combustion engine drivingly engaged to an engine shaft, a turbine section having an inlet in fluid communication with an outlet of the engine(s), the turbine section including at least one turbine compounded with the engine shaft, and a compressor having an inlet in fluid communication with an environment of the aircraft and an outlet in fluid communication with a bleed duct for providing bleed air to the aircraft, the compressor having a compressor rotor connected to a compressor shaft, the compressor shaft drivingly engaged to the engine shaft. The driving engagement between the compressor shaft and the engine shaft is configurable to provide at least two alternate speed ratios between the compressor shaft and the engine shaft.

An auxiliary power unit for an aircraft includes a rotary intermittent internal combustion engine drivingly engaged to an engine shaft, a turbine section having an inlet in fluid communication with an outlet of the engine(s), the turbine section including at least one turbine compounded with the engine shaft, and a compressor having an inlet in fluid communication with an environment of the aircraft and an outlet in fluid communication with a bleed duct for providing bleed air to the aircraft, the compressor having a compressor rotor connected to a compressor shaft, the compressor shaft drivingly engaged to the engine shaft. The driving engagement between the compressor shaft and the engine shaft is configurable to provide at least two alternate speed ratios between the compressor shaft and the engine shaft.

The disclosure provides rotary machines that include, in one embodiment, a shaft defining a central axis A, the shaft having a first end and a second end. The shaft can have a first gearbox disposed thereon defining one or more cavities therein. At least one contour is slidably received into an arcuate cavity in an exterior surface of the gearbox. The contour has a convex outer surface that cooperates with an inwardly facing curved surface of a housing to form a working volume. A gearbox mechanism consisting of gears, crankshafts, bearings and connecting rod creates an oscillatory motion 2 times per revolution such that the contour can navigate about the arcuate cavity without contacting the cavity at a high rate of rotating speed. Thus, said working volume can expand and compresses twice per rotatable shaft revolution.

The disclosure provides rotary machines that include, in one embodiment, a shaft defining a central axis A, the shaft having a first end and a second end. The shaft can have a first gearbox disposed thereon defining one or more cavities therein. At least one contour is slidably received into an arcuate cavity in an exterior surface of the gearbox. The contour has a convex outer surface that cooperates with an inwardly facing curved surface of a housing to form a working volume. A gearbox mechanism consisting of gears, crankshafts, bearings and connecting rod creates an oscillatory motion 2 times per revolution such that the contour can navigate about the arcuate cavity without contacting the cavity at a high rate of rotating speed. Thus, said working volume can expand and compresses twice per rotatable shaft revolution.

An engine assembly including an engine core including at least one internal combustion engine each including a rotor sealingly and rotationally received within a respective internal cavity to provide rotating chambers of variable volume in the respective internal cavity, a compressor having an outlet in fluid communication with an inlet of the engine core, a first intake conduit in fluid communication with an inlet of the compressor and with a first source of air, a second intake conduit in fluid communication with the inlet of the compressor and with a second source of air warmer than the first source of air, and a selector valve configurable to selectively open and close at least the fluid communication between the inlet of the compressor and the first intake conduit. A method of supplying air to a compressor is also discussed.

An engine assembly including an engine core including at least one internal combustion engine each including a rotor sealingly and rotationally received within a respective internal cavity to provide rotating chambers of variable volume in the respective internal cavity, a compressor having an outlet in fluid communication with an inlet of the engine core, a first intake conduit in fluid communication with an inlet of the compressor and with a first source of air, a second intake conduit in fluid communication with the inlet of the compressor and with a second source of air warmer than the first source of air, and a selector valve configurable to selectively open and close at least the fluid communication between the inlet of the compressor and the first intake conduit. A method of supplying air to a compressor is also discussed.

An engine includes a housing defining an annular bore and a piston assembly disposed within the annular bore. The engine includes at least one valve configured to oscillate between a first position within the annular bore to allow the piston assembly to travel from a first location proximate to the at least one valve to a second location distal to the at least one valve and a second position to define a combustion chamber relative to the piston assembly at the second location. The engine includes an exhaust gas port disposed in fluid communication with the combustion chamber and a fuel distribution assembly configured to mix fuel from a fuel source and air from an air source into a fuel and air mixture at a location external to the combustion chamber and to deliver the fuel and air mixture to the combustion chamber.

An engine includes a housing defining an annular bore and a piston assembly disposed within the annular bore. The engine includes at least one valve configured to oscillate between a first position within the annular bore to allow the piston assembly to travel from a first location proximate to the at least one valve to a second location distal to the at least one valve and a second position to define a combustion chamber relative to the piston assembly at the second location. The engine includes an exhaust gas port disposed in fluid communication with the combustion chamber and a fuel distribution assembly configured to mix fuel from a fuel source and air from an air source into a fuel and air mixture at a location external to the combustion chamber and to deliver the fuel and air mixture to the combustion chamber.

An assembly for an aircraft having a propeller, including a wheel well configured for receiving a retracted landing gear, the wheel well including walls and a closable bottom opening for deploying the landing gear therethrough, an engine assembly having an engine shaft configured for driving engagement with the propeller, and a mount assembly for supporting the engine assembly, the mount assembly connected to at least one of the walls of the wheel well. A method of supporting an engine assembly in an aircraft having a retractable landing gear and a propeller driven by the engine assembly is also discussed.

An assembly for an aircraft having a propeller, including a wheel well configured for receiving a retracted landing gear, the wheel well including walls and a closable bottom opening for deploying the landing gear therethrough, an engine assembly having an engine shaft configured for driving engagement with the propeller, and a mount assembly for supporting the engine assembly, the mount assembly connected to at least one of the walls of the wheel well. A method of supporting an engine assembly in an aircraft having a retractable landing gear and a propeller driven by the engine assembly is also discussed.