An auxiliary power unit (APU) system for an aircraft can include a fuel consuming system configured to generate and output electrical energy for use by one or more aircraft systems and a battery system configured to output stored electrical energy for use by the one or more aircraft systems. The fuel consuming system can include a fuel consuming APU, and an APU generator operatively connected to the fuel consuming APU and configured to convert APU motion into APU generator alternating current (AC). The system can include a high voltage AC line operatively connected to the generator. The battery system can include a battery configured to output battery direct current (DC).

Various components and methods related to a leading edge assembly are disclosed. The leading edge assembly can include an outer strike shell and a foam core. The foam core can be located inside the outer strike shell. The leading edge assembly can include a heating element with a plurality of sensors and wires. A method of manufacturing a leading edge assembly can include forming a composite layer, applying a metallic layer to the composite layer, installing an electronic device, and inserting a foam core into a cavity bounded by the composite layer and/or the electronic device.

One example of a mount for a rotorcraft comprises a structural support member, a bracket, and an elastomer. The bracket is configured to attach to a component of the rotorcraft. The component of the rotorcraft produces vibrations at a first frequency. The structural support member configured to transfer a weight of the component of a rotorcraft to an airframe of the rotorcraft. A rotor system of the aircraft vibrates the airframe of the rotorcraft at a second frequency. The elastomer is located between a structural support member and a bracket. The elastomer is configured to attenuate noise caused by the vibrations at the first frequency by isolating the vibrations at the first frequency from reaching the airframe of the rotorcraft while the airframe vibrates at the second frequency.

Systems and method for an electrical system on an aircraft are provided. In example aspects, the electrical system can be for an aircraft having a turbine engine. The turbine engine having a high pressure (HP) spool and a low pressure (LP) spool. The HP spool can be configured to drive a first generator to provide a first electrical output. The LP spool can be configured to drive a second generator to provide a second electrical output. The first generator and the second generator can be coupled to an electrical power distribution bus that provides electrical power to multiple high power demand loads. A propulsion system and a multiple aircraft systems bus can both be coupled to the electrical power distribution bus. The electrical system can further include a control system configured to allocate power among the first generator, the second generator, and the propulsion system, and the secondary aircraft systems bus.

An airplane has main propulsion engines and a first fuel supply for the main propulsion engines. The airplane further has an auxiliary propulsion engine and a second fuel supply for the auxiliary propulsion engine, this second fuel supply being separate from the first fuel supply. The auxiliary propulsion engine can be switched on independently from the main propulsion engines. Such airplane has increased safety, since it will be possible to maintain flight, particularly when at high altitude, even if all main propulsion engines have failed.

Methods and apparatus for accelerating an aircraft fuselage boundary layer via a fan powered by an APU of the aircraft are disclosed. An example aircraft includes a fuselage, an APU, and a fan. The fuselage includes an outer skin. The APU is located within the fuselage. The fan includes a plurality of fan blades arranged circumferentially about the APU and projecting radially outward from the outer skin. The fan further includes a fan drive operatively coupled to the APU. The fan drive is configured to rotate the fan blades in response to a supply of electrical energy provided to the fan drive from the APU. The rotation of the fan blades accelerates a fuselage boundary layer traveling rearward along the outer skin from a first velocity to a second velocity greater than the first velocity.

A system for supplying electrical energy to at least one electrical load of an aircraft, this system including a main source of electrical energy connected to at least one electrical load through an electrical network, the system including a control device connected to the main source of electrical energy and configured to deliver a variable voltage level on the electrical network based on a predetermined voltage variation law depending on at least one parameter characterizing the altitude of the aircraft and according to the Paschen law with a predefined margin.

An electric power generation controller for use in an aircraft to control an electric power generating apparatus including a manual transmission which changes speed of rotational power of an aircraft engine, transmits the rotational power to an electric power generator, and includes a plurality of gear stages. The electric power generation controller includes: a rotational frequency receiving section configured to receive an input rotational frequency or an output rotational frequency of the manual transmission as a monitoring rotational frequency; and a manual transmission control section configured to, when the monitoring rotational frequency exceeds a first threshold, output a shift-down signal to perform shift-down from an upper stage to a lower stage, and when the monitoring rotational frequency falls below a second threshold, output a shift-up signal to perform shift-up from the lower stage to the upper stage, the first threshold being set to a value larger than the second threshold.

An electric power generation controller for use in an aircraft is a controller of an electric power generating system configured such that: a manual transmission changes speed of rotational power of an aircraft engine; a continuously variable transmission changes the speed of the rotational power which has been changed in speed by the manual transmission; and the continuously variable transmission transmits the rotational power to an electric power generator. The electric power generation controller includes: a manual transmission control section configured to, when a predetermined shift condition is satisfied, control the manual transmission to switch a gear stage of the manual transmission; and a continuously variable transmission control section configured to, when the shift condition is satisfied, control the continuously variable transmission to such a side that fluctuation of an output rotational frequency of the manual transmission by the switching of the gear stage of the manual transmission is canceled.

The invention relates to an aircraft incorporating an enhanced power unit for generating electric, pneumatic and/or hydraulic power for the aircraft during all stages of the aircraft operation. The power unit (1) comprises: a heat engine (14) with a drive shaft (2) and a combustion gases exhaust (7). The power unit (1) also includes a Rankine cycle system (12) for recovering thermal energy from a heat source of the power unit (1) for the assistance of the heat engine (14). The heat source for the Rankine cycle system can be taken from the exhaust gases of the heat engine, from the oil coolant circuit of the heat engine or from the output of a compressor driven by the heat engine. Preferably, the aircraft cabin air is reused as a source of oxygen for the combustion. The invention reduces bleed air extraction from the aircraft main engines thereby reducing fuel consumption.