Abstract: A compressed air supply system includes: a bleed air passage; an auxiliary compressor structure including a compressor inlet and a compressor outlet, the compressor inlet being fluidly connected to the bleed air passage; a supply passage which is fluidly connected to the compressor outlet and through which compressed air from the auxiliary compressor structure is supplied to an air cycle machine; an accessory gear box; and a continuously variable transmission structure that changes speed of rotational driving force output from the accessory gear box and rotates the auxiliary compressor structure. The continuously variable transmission structure and the auxiliary compressor structure are fixed to the accessory gear box, and the accessory gear box is fixed to the gas turbine engine.

Abstract: A flying object 20 is provided with a rotor blade 200 that generates lift and thrust by rotating and a rotating electrical machine unit that rotates the rotor blade 200. The rotor blade 200 receive wind power and rotate when not flying. The rotating electrical machine unit generates electric power based on a power that rotates the rotor blades 200 when not flying. In addition, the flying object 20 may be provided with a power storage device 230 that stores electric power generated by the rotating electrical machine unit. In addition, the flying object 20 may be provided with a detachably connected cartridge 260 that has a desired function.

Abstract: A hybrid electric propulsion (HEP) system included in an aircraft includes a generator configured to output a first power, an energy storage system configured to output a second power, a propulsion system configured to generate thrust based on at least one of the first power and the second power, and an HEP controller in signal communication with the generator, the battery, and the HEP system. The HEP controller is configured to detect loss of the first power output from the generator, to determine an altitude of the aircraft and to actively control delivery of the second power to the propulsion system based on the altitude during the loss of the first power.

Abstract: The aircraft can include a rotary airfoil device having an output shaft rotatable around an airfoil rotation axis; an electric engine having a source shaft drivingly coupled to the output shaft; a controller in communication with the electric engine; a low voltage electric system operable to power the controller; a high voltage electric system having a high voltage battery operable to power the electric engine, the high voltage battery further operable to power the low voltage electric system via a voltage converter; and an electromagnetic generator having a generator shaft coupled to the output shaft, the electromagnetic generator operable to power the low voltage electric system.

Abstract: An unmanned aerial vehicle and a battery, possible to be disabled when a phenomenon to cause a functional disorder, are provided. The battery includes a battery pack having a battery cell, sensors detecting a phenomenon that impairs a function of the battery pack, a memory storing a detection signal of the sensors, and block circuits blocking output of the battery pack by the detection signal. The unmanned aerial vehicle includes the battery and air frame side sensors, and operates the block circuit, which the battery includes, by the detection signal of the airframe side sensors.

Abstract: The present disclosure provides methods of coating a substrate. A method includes depositing a conductive coating including an electrically conductive material over the substrate to form a conductive layer having a sheet resistivity of about 10?/? to about 1000?/?. The method includes depositing an anti-icing layer comprising nanomaterials over the conductive layer to form a coating system.

Abstract: Systems and methods of aircraft thrust management are provided. For example, a propulsion system for an aircraft comprises a fuel cell assembly comprising a fuel cell, a turbomachine, and a controller comprising memory and one or more processors. The memory stores instructions that, when executed by the one or more processors, cause the propulsion system to perform operations including receiving data indicative of a propulsion system thrust discrepancy and modifying an output of the fuel cell in response to receiving data indicative of the propulsion system thrust discrepancy. Modifying the fuel cell output may include modifying output products, an electrical power output, or both of the fuel cell to balance the thrust provided by the propulsion system.

Abstract: Disclosed is a system for humidifying cabin and/or cockpit air of a fuel cell-powered aircraft system. The system includes a fuel cell stack configured for reacting hydrogen and oxygen to produce electrical energy and a cathode exhaust containing moist, warm air; a water separator configured to cool the moist, warm air and to condense and separate liquid water from the moist, warm air; and a humidifier configured to employ the separated liquid water to humidify pressurized cabin air.

Abstract: Systems and methods are configured for power distribution in a hybrid fixed-wing VTOL drone aircraft. A drone aircraft includes two modes of operation. In a first mode of operation, the internal combustion engine is shut off while an electric motor-based VTOL system provides lift and thrust. In a second mode of operation, an internal combustion engine provides thrust while a set of fixed wings provide lift. In the second mode of operation, mechanical power from the internal combustion engine provides for power generation to charge an electrical battery to power the electric motor-based VTOL system.

Abstract: Methods, systems and apparatus, including computer programs encoded on computer storage media for fleet management of unmanned aerial vehicles, including flight authorization. One of the methods includes maintaining one or more rules associated with authorizing UAVs to implement flight plans. A request to generate a flight plan associated with a job is received, the request including information indicating a flight pattern comprising, at least, one or more waypoints associated with geospatial references. The flight plan is generated based on the request, and an initial authorization check is determined based on the maintained rules and the generated flight plan. Upon a positive determination, access to the generated flight plan is provided by a ground control system, and the flight plan is implemented.

Abstract: An aircraft is described comprising: a support element; a shaft rotating about an axis; a pair of oblique rolling bearings mounted so as to couple the shaft to the support element rotatingly about the axis; the rolling bearings comprising: respective first races cooperating radially in contact with a first component defined by one from the support element and the shaft; respective second races cooperating radially in contact with a second component defined by the other from the support element and the shaft; and respective pluralities of rolling elements adapted to roll on the first and second races; the aircraft further comprises a pair of preloaded elastic members, which couple the first races to the first component respectively, axially and in an elastically yielding manner.

Abstract: In a drone system in which a drone and a movable body operate in coordination with each other, the drone performing a predetermined operation in an agricultural field, the movable body being capable of moving with the drone aboard and allowing the drone to make a takeoff and a landing, the plan determining section determines a flight plan for the drone and a movement plan for the movable body in accordance with the flight plan, and the instructing section instructs the drone to execute an operation in accordance with the flight plan and instructs the movable body to move or to be on standby in accordance with the movement plan.

Abstract: A gas turbine engine has an accessory gearbox disposed outside of a bypass channel and connected to a housing part, which radially delimits the bypass channel, in a connection region near the housing part and in a connection region far from the housing part. A connecting element is provided between the housing part and the connection region far from the housing part. A longitudinal axis of the connecting element includes an angle in the range of 75° to 115° with a vertical axis of the accessory gearbox. The connecting element can vary a distance between the far connection region and a connection point of the connecting element on the housing part such that deformation of the housing part and a resulting position change of the connection point cause a lesser deflection of the accessory gearbox than a deflection with an unchanged length of the connecting element.

Abstract: A propulsion system includes two gas turbine engines and an air-provisioning system. The air-provisioning system includes a first ejector, a second ejector, a plenum fluidically connected with the first ejector and the second ejector, and a first propulsor. The air-provisioning system is configured to bleed and mix air from each gas turbine engine in the ejectors so as to provide selectively a flow of plenum air from the plenum to the first propulsor at a desired pressure and a desired flow rate to power the first propulsor.

Abstract: A ram air turbine (RAT) assembly includes a turbine having at least one turbine blade that rotates about a turbine driveshaft, a lower gear box coupled to the driveshaft, a generator/pump housing and a strut connected between the lower gear box and the generator/pump housing. The assembly also includes a damping element connected to one of the strut and the lower gear box. The damping element includes an actuator including an extendable member and a mass element connected to the extendable member and that can be moved by the extendable member from a retracted position to an extended position, wherein the mass element is closer to the actuator when in the retracted position than when in the extended position.

Abstract: Aircraft generator systems are described. The aircraft generator systems include a main engine having a fan and a compressor section, a generator assembly having at least one expansion turbine operably connected to a generator, and a working fluid flow path defined between at least one extraction point at at least one of the fan and the compressor section of the main engine and at least one outlet, wherein the working fluid is configured to flow through the at least one expansion turbine to generate power at the generator. There are no heat exchangers arranged between the at least one extraction point and the at least one outlet along the working fluid flow path.

Abstract: A hybrid-electric aircraft system is provided and includes first and second hybrid-electric engines, first and second ducting systems fluidly communicative with each other and with the first and second hybrid-electric engines, respectively, and a control system. The control system is operably coupled to each of the first and second hybrid-electric engines and to each of the first and second ducting systems. The control system is configured to run the first hybrid-electric engine normally, to run the second hybrid-electric engine in a lower power mode and to control each of the first and second ducting systems to direct bleed air from the first hybrid-electric engine to the second hybrid-electric engine.

Abstract: Propulsion assembly for an aircraft, comprising a fuselage extending along a longitudinal axis and enclosing an inner enclosure, at least one ducted engine fixed to the fuselage and comprising an air inlet section, the air inlet section being disposed at least partly in the inner enclosure, at least one plenum chamber disposed in the inner enclosure upstream of the air inlet section and in fluid communication with said air inlet section, at least one air intake formed on an outer wall of the fuselage, the inlet of the air intake being partly delimited by said outer wall of the fuselage, the air intake being configured to ingest external air and deflect it towards the plenum chamber.

Abstract: A hydrogen storage system comprises a hydrogen tank and a system for controlling hydrogen evaporation in the hydrogen tank. This control system comprises a hydrogen discharge pipe connected to the hydrogen tank, on the one hand, and to a controllable valve, on the other hand, as well as a processing unit configured to control the valve as a function of the pressure in the tank. The hydrogen storage system further comprises a fuel cell permanently connected to the hydrogen tank and the processing unit being electrically powered by the fuel cell.

Abstract: A fan module for an aircraft turbine engine, this module comprising a fan and an electrical machine, such that the electrical machine is coaxially mounted downstream of the fan and comprises a rotor coupled to rotate with the fan and an annular member with generally C-shaped axial cross-section, the opening of which is axially orientated and receives the rotor, this member comprising a radially outer portion forming a stator, and a radially inner portion forming a support for bearings guiding the rotor.

Abstract: A gas turbine engine includes a first spool rotationally coupled to a plurality of accessories via a first gearing and a second spool rotationally coupled to a third spool via a second gearing. The first gearing and the second gearing rotate independently and are enclosed within a housing of an accessory gearbox. A method of operating the gas turbine engine includes supplying a first fuel flow rate to a primary combustor associated with the first and third spools and supply a second fuel flow rate a secondary combustor associated with the second spool based on a power lever angle within an intermediate power level range.

Abstract: A propulsion system for an aircraft having an aft end is provided herein. The propulsion system can include an electric propulsion engine defining a central axis. The electric propulsion engine can include an electric motor, a fan rotatable about the central axis of the electric propulsion engine by the electric motor, a bearing supporting rotation of the fan, and a thermal management system. The thermal management system can include a lubrication oil circulation assembly for providing the bearing with lubrication oil. The lubrication oil circulation assembly can be driven independently of a shaft of the electric propulsion engine.

Abstract: In an asymmetric operating regime, a first engine is operating in an active mode to provide motive power to an aircraft while a second engine is operating in a standby mode and de-clutched from a gearbox of the aircraft. In response to an emergency exit request, the second engine's speed is increased, at a maximum permissible rate, to a re-clutching speed while increasing the first engine's power output at a maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a maximum permissible rate. In response to a normal exit request, the second engine's speed is increased to the re-clutching speed at a rate lower than the maximum permissible rate. When the re-clutching speed is reached, the second engine's power output is increased at a rate lower than the maximum permissible rate.

Abstract: A strut system for a RAT includes a strut body, a strut first end is connected to the aircraft and rotate about a first axis, a strut second end is spaced apart from the strut first end by the strut body and is connected to the RAT turbine generator unit, the strut has a strut conduit extending from the strut first end toward the strut second end; and a damper rod that includes a rod body and disposed within the strut conduit, the damper rod having a rod first end that is fixed within the strut conduit at the strut first end, and a rod second end that is spaced apart from the rod first end by the rod body and is located intermediate the strut first end and the strut second end, wherein the rod second end moves along a second axis that is parallel to the first axis.

Abstract: A ram air turbine release system including a turbine defining a rotational axis including at least one notch therein for receiving a plunger to prevent rotation of the turbine mechanically by moving between a first position and a second position, and a first bearing system contacting at least a portion of an outer surface of the plunger configured to reduce friction produced when the plunder moves between the first positon and the second position.

Abstract: An aircraft power plant has a hybrid propulsion system having an electric motor, a combustion engine, an output shaft drivingly connectable to a thrust generator, a compressor, and a transmission having a first transmission drive path and a second transmission drive path, the combustion engine and the output shaft in driving engagement with the first transmission drive path, the electric motor selectively drivingly engageable to the compressor via either the first drive path or via the second drive path.

Abstract: A hybrid engine includes a gas turbine engine having at least one compressor section and at least one turbine section operably coupled to a shaft. The hybrid engine includes an electric motor configured to augment rotational power of the shaft of the gas turbine engine. A controller is operable to monitor for a transient operation request of the hybrid engine, provide the transient operation request to one or more management systems of the hybrid engine to determine whether one or more faults are detected by the one or more management systems, modify one or more stall margin adjustment parameters of the gas turbine engine based on detecting the one or more faults by the one or more management system, and adjust operation of the hybrid engine based on the one or more stall margin adjustment parameters.

Abstract: In accordance with at least one aspect of this disclosure, an electric aircraft can include an electrical accumulator, an electric propulsion system operatively connected to the electrical accumulator and configured to convert electrical energy into propulsive force, and a ram air turbine (RAT) operatively connected to the electrical accumulator to store energy. The RAT can be selectively deployable between a stowed position wherein the RAT is not exposed to ram air and a deployed position wherein the RAT is exposed to ram air to store energy in the electrical accumulator.

Abstract: An energy harvesting system is provided and a corresponding method for harvesting energy from an aircraft cabin pressurization system utilizing the same. According to one aspect, an energy harvesting system includes an aircraft cabin enclosing a high-pressure environment of pressurized air. An air input receives incoming air from a low-pressure environment and an air output expels outgoing air from the high-pressure environment. A turbine receives the pressurized air expelled from the aircraft cabin and utilizes the pressurized air to produce rotational motion on a turbine shaft. An energy harvesting mechanism is coupled to the turbine shaft and utilizes the rotational motion from the turbine shaft to compress the incoming air or to create electrical energy.

Abstract: A device for the automated charging and discharging of an object on a free-flying autonomously controlled drone includes a landing platform for the drone, a storage device for storing objects, a robot where the robot is configured to remove an object from the storage apparatus in an automated manner and to provide the object on the landing platform to be picked up by the drone and is configured to pick up in an automated manner an object that is provided on the landing platform by the drone and to deposit the object in the storage apparatus, and a controller where the robot is controllable by the controller.

Abstract: This disclosure is generally directed to a High Speed vertical takeoff and landing (VTOL) aircraft that includes fixed wing flight capabilities. The High Speed VTOL aircraft may include at least two thrust producing rotors located equidistant from a longitudinal axis of the aircraft on a main wing, and at least two thrust producing rotors located equidistant from a longitudinal axis of the aircraft on a vertical wing. The rotors may be driven by electric motors. However, other power sources may be used such as combustion or hybrid engines. By adjusting the speed and/or the pitch of the rotors, the aircraft can transition from a vertical flight configuration to a horizontal flight configuration and back.

Abstract: A micro-auxiliary power unit for supplying electric power to a vehicle includes a thermal resistant enclosure having an intake duct for receiving air, and a source of fuel. A fuel valve is fluidly coupled from the enclosure, and the fuel valve is movable between an opened position and a closed position. The micro-auxiliary power unit includes a Wankel engine to drive an output shaft and a starter-generator coupled to the output shaft to generate electric power. The micro-auxiliary power unit includes a system that has at least one sensor disposed within the enclosure that observes a condition of the enclosure and generates sensor signals, and a controller having a processor that receives the sensor signals, determines the presence of a thermal event within the enclosure and based on the determination, outputs one or more control signals to the fuel valve to move the fuel valve to the closed position.

Abstract: An aircraft power plant has: a hybrid propulsion system having an electric motor, an output shaft drivingly connectable to a thrust generator, a combustion engine, a compressor, and a transmission having a first transmission drive path and a second transmission drive path selectively engageable to the first transmission drive path, the electric motor and the compressor in driving engagement with the first transmission drive path, the combustion engine and the output shaft in driving engagement with the second transmission drive path.

Abstract: An aspect includes a hybrid gas turbine engine system of a hybrid electric aircraft. The hybrid gas turbine engine system includes a gas turbine engine, an electric motor operable to perform an electric taxiing of the hybrid electric aircraft, and a controller. The controller is operable to prevent fuel flow to the gas turbine engine during at least a portion of the electric taxiing and monitor for a powered warm-up request during the electric taxiing. A powered warm-up state of the gas turbine engine is initiated based on detecting the powered warm-up request. The powered warm-up state adds heat to one or more components of the gas turbine engine prior to transitioning to a takeoff power state. The gas turbine engine transitions from the powered warm-up state to the takeoff power state after reaching a target temperature of the one or more components in the powered warm-up state.

Abstract: A multi-modal multi-media air filtration system which can include: a base having one or more connection features and a filter media assembly, the filter media assembly being configured to attach to the base portion at a first end. The filter media assembly can then also include a first filter media extending across a first air flow path and a second filter media extending across a second air flow path. The air filtration assembly can then also include an actuation assembly configured to selectively open or close one of the first air flow path or the second air flow path so as to alternate the degree of filtration passing through the filter media assembly based on the degree of filtration provided by the first or second filter media.

Abstract: The invention regards an asymmetric submerged air intake in a surface of a structure, wherein the air intake includes a submerged ramp extending from the surface. The ramp has a front end, a rear end, a ramp floor and two ramp side walls. The ramp floor is inclined with respect to the surface. At the rear end an entrance to an internal duct of the structure is provided. It is provided that one of the ramp side walls is a straight wall extending straight in the longitudinal direction of the ramp and that the other of the ramp side walls is a curved wall that diverges from the straight wall along the length of the ramp.

Abstract: The fuel cell system according to one embodiment of the present invention includes the solid oxide fuel cell configured to generate power by receiving the supply of the cathode gas and the anode gas. The fuel cell system includes a discharging passage configured to discharge the cathode off-gas and the anode off-gas discharged by the fuel cell as discharged gas to the outside, a discharged-gas temperature detection unit configured to detect or estimate the temperature of the discharged gas discharged from the discharging passage, an air supplying unit configured to supply air to the discharging passage, and the control unit configured to control the air supply to be executed by an air supplying unit on the basis of the detected or estimated temperature.

Abstract: A multi-zone battery station is provided, comprising a plurality of landing areas configured to support a UAV. The battery station may permit battery life to be reloaded onto a UAV, which may include recharging a battery of the UAV or exchanging the UAV battery for a new battery. The different zones may accommodate different UAV types, different battery types, or operate in accordance with different energy provision rules. A marker may be provided on a landing area to aid in guiding the UAV to an appropriate landing area.

Abstract: A toggle release mechanism comprises a platform, a toggle element comprising one or more rolling or sliding elements configured to move along a track between a first, locking position and a second, release position, and a solenoid configured to move the one or more rolling or sliding elements along the track between the first, locking position and the second, release position.

Abstract: A distributed auxiliary-power-unit (APU) system for an aircraft includes one or more battery modules for storing electrical power, and a plurality of racks distributed throughout the aircraft for receiving the one or more battery modules to electrically connect with an electrical subsystem of the aircraft. A plurality of hot-swappable racks are adapted to receive the battery modules for electrically and communicatively coupling with the electrical subsystem and an integrated controller. A remote interface is communicatively coupled with the integrated controller for receiving user-input to direct electrical power from the battery modules to one or more subsystems of the aircraft. A number of battery modules installed is based on an amount of electrical power planned for a given flight of the aircraft.

Abstract: Pressurized air systems for aircraft and related methods are described herein. An example pressurized air system includes a compressor having a compressor inlet and a compressor outlet. The compressor inlet receives air from a first air source and the compressor outlet supplies pressurized air to an environmental control system (ECS). The pressurized air system includes a turbine having a turbine inlet to receive air from a second air source, a first overrunning clutch operatively coupled between an output shaft of an accessory gearbox and the compressor, the accessory gearbox operatively coupled to a drive shaft extending from an engine of the aircraft, and a second overrunning clutch operatively coupled between the compressor and the turbine. The first and second overrunning clutches enable the accessory gearbox to drive the compressor during a first mode of operation and enable the turbine to drive the compressor during a second mode of operation.

Abstract: Aircraft fuselage apparatus having embedded structural batteries are disclosed. An example apparatus includes a fuselage having a wall. The wall has an outer surface, an inner surface, and a structural battery embedded in the wall between the outer surface and the inner surface.

Abstract: Aspects of the subject disclosure may include, for example, obtaining power, by a communication device, from a current passing through a transmission medium via an inductive coupling between the communication device and the transmission medium where the communication device is physically connected with the transmission medium and providing communications, by the communication device, by electromagnetic waves that propagate without utilizing an electrical return path, wherein the electromagnetic waves are guided by one of the transmission medium or a dielectric core of a cable coupled to a feed point of a dielectric antenna. Other embodiments are disclosed.

Abstract: An emergency wind turbine system for an aircraft including an outer structure in which an opening is made includes an emergency wind turbine including: a mast; a turbine including a body mounted on the mast that rotates about an axis of rotation, and a single blade or two blades extending radially from the body between a blade root and a blade head; a locking device to lock rotation of the turbine body about the axis of rotation, when the emergency wind turbine moves between retracted and deployed positions, such that the blade root axis forms an acute locking angle with an orthogonal projection of the longitudinal axis of the mast over a plane substantially perpendicular to the axis of rotation of the turbine and in which the blade root axis extends, to reduce the volume swept by the turbine when it moves between the retracted and deployed positions.

Abstract: A multimode clutch assembly is positioned in a powertrain of a rotorcraft. The multimode clutch assembly includes a freewheeling unit having input and output races. The freewheeling unit has a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly has an engaged position that couples the input and output races of the freewheeling unit. A hydraulic actuator shifts the bypass assembly between the engaged position and a disengaged position. In the disengaged position, the overrunning mode of the freewheeling unit is enabled such that the multimode clutch assembly is configured for unidirectional torque transfer. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the multimode clutch assembly is configured for bidirectional torque transfer.

Abstract: A selectable clutch assembly for a multimode powertrain of a rotorcraft. The selectable clutch assembly includes a freewheeling unit having input and output sides. The freewheeling unit has a driving mode wherein torque applied to the input side is transferred to the output side and an over running mode wherein torque applied to the output side is not transferred to the input side. A bypass assembly is coupled to and rotatable with the output side of the freewheeling unit and is actuatable between engaged and disengaged positions with the input side of the freewheeling unit. In the disengaged position, the freewheeling unit is operable in the driving and the over running modes such that the selectable clutch assembly is configured for unidirectional torque transfer. In the engaged position, the over running mode of the freewheeling unit is disabled such that the selectable clutch assembly is configured for bidirectional torque transfer.

Abstract: A ram air turbine system includes a ram air turbine and an actuator to move the ram air turbine between a stowed position and a deployed position. The actuator is in fluid communication with an aircraft hydraulic system configured to return the ram air turbine to the stowed position from the deployed position during operation of the aircraft utilizing hydraulic fluid pressure from the aircraft hydraulic system. A method of operating a ram air turbine system includes slowing or stopping rotation of the ram air turbine during flight of the aircraft, directing hydraulic fluid pressure from an aircraft hydraulic system to a ram air turbine actuator to urge movement of the actuator from a deployed position to a stowed position and urging movement of the ram air turbine from a deployed position to a stowed position via movement of the actuator from the deployed position to the stowed position.

Abstract: Described in detail herein is an temperature-controlled UAV delivery system. One or more physical objects can be stored inside a temperature-controlled storage unit of a UAV. A temperature controlling device can control the temperature of the interior volume of the temperature-controlled storage unit. Sensors can detect a temperature of the interior volume of the temperature-controlled storage unit. The computing system can control the temperature controlling device to adjust the temperature of the interior volume of the temperature-controlled storage unit to an ideal temperature for storing the one or more physical objects based on the attributes associated with the one or more physical objects.

Abstract: A propeller for an aircraft having a fuselage and a pair of fixed wings includes a mounting member secured to at least one wing. At least one blade is rotatably connected to each mounting member and has an airfoil shape. The at least one blade is in a locked condition during take-off and landing of the aircraft extending parallel to a leading edge of the wing and in an unlocked, rotating condition during flight for propelling the aircraft.

Abstract: A gas turbine engine assembly includes a turbine section having first and second turbines mounted for rotation about a common rotational axis within an engine static structure, first and second turbine shafts coaxial with one another and to which the first and second turbines are respectively operatively mounted, first and second towershafts respectively coupled to the first and second turbine shafts, an accessory drive gearbox mounted to the engine static structure, and a transmission transitionable between a first mode where an electric machine is driven at a first speed relative to the first towershaft, and a second mode where the electric machine is driven at a different, second speed relative to the first towershaft.