A method and apparatus for controlling a propeller of a contra-rotation open fan (CROF) engine of an aircraft is provided. A diameter of the propeller is set to be at a first diameter during at least a portion of a first flight condition of the aircraft. The diameter of the propeller is set to be at a second diameter, different from the first diameter, during at least a portion of a second flight condition of the aircraft.

An aircraft propulsion power plant for use in an aircraft includes one or more core engines housed in an airframe of the aircraft, one or more secondary propulsion units, each of the one or more secondary propulsion units being removably attached to the airframe, and one or more power transmission means, each of the one or more power transmission means being configured to transmit mechanical power from the or each core engine to a corresponding one of the or each secondary propulsion unit when the or each secondary propulsion unit is attached to the airframe.

The invention relates to a method for providing predefined desired drive characteristics (38, 50) in an aircraft, characterized by the following steps: driving a thrust generation element of the aircraft by means of an electric motor that has actual drive characteristics (34) which include at least some of the desired drive characteristics (38, 50) but are also partly different therefrom; andhaving a control device adjust operating points of the electric motor exclusively according to the desired drive characteristics (38, 50).

A propulsion system for an aircraft is provided having an aft engine configured to be mounted to the aircraft at an aft end of the aircraft. The aft engine includes a fan rotatable about a central axis of the aft engine having a plurality of fan blades attached to a fan shaft. The aft engine also includes a nacelle encircling the plurality of fan blades and a structural support system for mounting the aft engine to the aircraft. The structural support system extends from the fuselage of the aircraft, through the fan shaft, and to the nacelle when the aft engine is mounted to the aircraft. The aft engine may increase a net thrust of the aircraft when mounted to the aircraft.

Embodiments refer generally to systems and methods for providing autorotative enhancement for helicopters using an autorotative assist unit coupled to the transmission of the helicopter. Methods of utilizing an autorotative assist unit as well as retrofitting an autorotative assist unit to an existing helicopter are also disclosed. By employing an autorotative assist unit, improved autorotation can be achieved without the need to increase the weight of the rotor.

The invention relates to an architecture of a propulsion system of a multi-engine helicopter, comprising turboshaft engines (1, 2) that are connected to a power transmission gearbox (3), and comprising a low DC voltage onboard network (7) for supplying helicopter equipment during flight, characterised in that it comprises: a hybrid turboshaft engine (1) that is capable of operating in at least one standby mode during a stable flight of the helicopter; an electrotechnical pack (20) for quickly restarting said hybrid turboshaft engine in order to bring said engine out of said standby mode and to reach a mode in which it provides mechanical power, said restart pack (20) being connected to said onboard network (7); and at least two sources (4, 16, 18) of electrical power for said onboard network (7).

A contra-rotating propeller system for an aircraft turbine engine, including a free power turbine including a first rotor and a second rotor contra-rotating relative to the first rotor, a first contra-rotating propeller and a second contra-rotating propeller to be rotated about a longitudinal axis of the propeller system relative to a stator of the system, and a mechanical transmission device. The mechanical transmission system is provided between the first propeller and the second propeller.

This disclosure generally relates to a hybrid solid-state propulsion system for aerial vehicles which includes a thermoelectric generator. The thermoelectric generator includes a first heat exchanger disposed within an exhaust duct of an unmanned aerial vehicle. The thermoelectric generator further includes a first ceramic layer disposed on the first heat exchanger and a first and second metal tab bonded to the first ceramic layer. The thermoelectric generator further includes a second metal tab bonded to a second ceramic layer. At least one N-type thermoelectric leg is disposed between the first metal tab bonded to the first ceramic layer and the metal tab bonded to the second ceramic layer. Further, at least one P-type thermoelectric leg is disposed between the second metal tab bonded to the first ceramic layer and the metal tab bonded to the second ceramic layer.

A gyroscopic orbiter with vertical takeoff and vertical landing capabilities can transition between different functional modes while in-flight. The orbiter typically includes a fuselage, a front boom, a front propulsion unit, a rear boom, and a rear propulsion unit. The front boom is mounted at two pivot points to a bow of the fuselage by the front boom. The rear boom is mounted at two pivot points to a stern of the fuselage by the rear boom. One functional mode is the vertical takeoff and landing mode, wherein the propulsion units are oriented parallel to each other and are directed upward. Another functional mode is the shuttle mode, wherein the propulsion units are oriented at an angle with each other, and the front propulsion unit is directed forward. Another functional mode is the high speed mode, wherein the propulsion units are oriented collinear with a roll axis of the fuselage.

A power and propulsion system includes an air compressor, a combustor positioned to receive compressed air from the air compressor as a core stream, and a closed-loop system having carbon dioxide as a working fluid that receives heat from the combustor and rejects heat to a cooling stream. The closed-loop system configured to provide power to a fan that provides the cooling stream, and to one or more distributed propulsors that provide thrust to an aircraft.