A multicopter having a plurality of propellers is provided with electric motors, at least one main battery, a generator, and an engine. The electric motors drive the propellers. The main battery is a first electric power source that supplies the electric power to the electric motors. The generator is a second electric power source that supplies the electric power to the electric motors. The engine drives the generator. When a remaining capacity of the main battery is less than a threshold, the generator charges the main battery with the electric power that has been converted from motive power from the engine.

The invention relates to an aircraft comprising a drive system having a power unit, at least one drive battery, and at least one electric motor drawing electrical energy from the at least one drive battery, wherein the power unit comprises a two-cylinder reciprocating-piston engine having two cylinder-piston units in tandem arrangement and comprises at least one generator for generating electrical energy, wherein each cylinder-piston unit has a crankshaft, and wherein the crankshafts are mechanically coupled to each other, and wherein at least one crankshaft is mechanically connected to the at least one generator. The invention also relates to additional improvements of the aircraft and to an operating method.

The invention relates to an aircraft comprising a drive system having a power unit, at least one drive battery, and at least one electric motor drawing electrical energy from the at least one drive battery, wherein the power unit comprises a two-cylinder reciprocating-piston engine having two cylinder-piston units in tandem arrangement and comprises at least one generator for generating electrical energy, wherein each cylinder-piston unit has a crankshaft, and wherein the crankshafts are mechanically coupled to each other, and wherein at least one crankshaft is mechanically connected to the at least one generator. The invention also relates to additional improvements of the aircraft and to an operating method.

There is disclosed an engine assembly, including an internal combustion engine having a housing and a coolant circuitry in heat exchange relationship with the housing. A porous surface is configured for defining a portion of an external surface of an aircraft. Apertures are defined through the porous surface. The housing of the internal combustion engine is in heat exchange relationship with the porous surface for heating the porous surface. An air conduit has an inlet fluidly connected to a boundary layer region outside the engine assembly and adjacent the porous surface via the apertures of the porous surface. The air conduit is in heat exchange relationship with the coolant circuitry. A forced air system is fluidly connected to the inlet of the air conduit and is operable to draw an airflow from the inlet and inside the air conduit. A method of operating the engine assembly is disclosed.

An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. The inner fan is configured to have, in operation, a rate of rotation of from 3 to 8 times that of the outer fan.

An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. The inner fan is configured to have, in operation, a rate of rotation of from 3 to 8 times that of the outer fan.

A control system for an aero compression combustion drive assembly, the aero compression combustion drive assembly having an engine member, a transmission member and a propeller member, the control system including a sensor for sensing a pressure parameter in each of a plurality of compression chambers of the engine member, the sensor for providing the sensed pressure parameter to a control system device, the control system device having a plurality of control programs for effecting selected engine control and the control system device acting on the sensed pressure parameter to effect a control strategy in the engine member A control method is further included.

A control system for an aero compression combustion drive assembly, the aero compression combustion drive assembly having an engine member, a transmission member and a propeller member, the control system including a sensor for sensing a pressure parameter in each of a plurality of compression chambers of the engine member, the sensor for providing the sensed pressure parameter to a control system device, the control system device having a plurality of control programs for effecting selected engine control and the control system device acting on the sensed pressure parameter to effect a control strategy in the engine member A control method is further included.

A method of operating a compoundable engine that includes a turbine having a turbine shaft and an intermittent internal combustion engine having an engine shaft. The engine shaft is rotated at a first rotational speed. The turbine is driven by exhaust gases of the intermittent internal combustion engine to rotate the turbine shaft while the engine shaft rotates independently from the turbine shaft. A rotatable load is driven with the turbine shaft. A rotational speed of the engine shaft is increased from the first rotational speed until the turbine shaft reaches a predetermined rotational speed. After the turbine shaft has reached the predetermined rotational speed, the rotational speed of the engine shaft is adjusted until the turbine shaft and the engine shaft are drivingly engageable with each other, and the turbine shaft with the engine shaft are engaged such that both are in driving engagement with the rotatable load.

A method of operating a compoundable engine that includes a turbine having a turbine shaft and an intermittent internal combustion engine having an engine shaft. The engine shaft is rotated at a first rotational speed. The turbine is driven by exhaust gases of the intermittent internal combustion engine to rotate the turbine shaft while the engine shaft rotates independently from the turbine shaft. A rotatable load is driven with the turbine shaft. A rotational speed of the engine shaft is increased from the first rotational speed until the turbine shaft reaches a predetermined rotational speed. After the turbine shaft has reached the predetermined rotational speed, the rotational speed of the engine shaft is adjusted until the turbine shaft and the engine shaft are drivingly engageable with each other, and the turbine shaft with the engine shaft are engaged such that both are in driving engagement with the rotatable load.