A hybrid turbofan engine including a planetary gear set for mixing power between an electrical output and a variable thrust bypass fan

Abstract

The aircraft powerplant includes an engine having a power output shaft. The aircraft powerplant also includes a power transmission coupled to the power output shaft of the engine. The power transmission is configured to divide a power output of the engine between a mechanical power output and an electric power output. A majority of the power output from the engine is adjustable to be output to either the mechanical power output or the electric power output. The aircraft powerplant further includes a propulsion mechanism coupled to the mechanical power output. The aircraft powerplant further includes a control system configured for the power transmission to either route a majority of the power output of the engine to the propulsion mechanism to generate thrust or route a majority of the power output of the engine as electric power output via the electric power output.

Description

[Technical field]

[0001] The present application relates to a hybrid turbofan engine that includes a planetary gear set for mixing power between an electrical output and a variable thrust bypass fan. [Background technology]

[0002] There are various types of aircraft that are propelled using different types of propulsion mechanisms, such as propellers, turbine or jet engines, rockets, or ramjets. Different types of propulsion mechanisms may be driven in different ways. For example, some propulsion mechanisms, such as propellers, may be driven by an internal combustion engine or an electric motor. Other propulsion mechanisms, such as turbofans or turboshafts, may be driven by a turbine engine. Summary of the Invention

[0003] In one embodiment, the aircraft powerplant includes an engine having a power output shaft. The aircraft powerplant further includes a power transmission coupled to the power output shaft of the engine. The power transmission is configured to split a power output of the engine between a mechanical power output and an electrical output. A majority of the power output from the engine is adjustable to be output to either the mechanical power output or the electrical output. The aircraft powerplant further includes a propulsion mechanism coupled to the mechanical power output. The aircraft powerplant further includes a control system configured to cause the power transmission to either send a majority of the power output of the engine to the propulsion mechanism to generate thrust or send a majority of the power output of the engine as electrical power output via an electrical power output.

[0004] In one embodiment, a method of splitting power output from an engine of an aircraft between an electrical output and a mechanical power output includes controlling a power train of the aircraft in a first mode of operation to generate electrical power using substantially all of the electrical power of the power output from the engine, the method further includes controlling the power train in a second mode of operation to generate little or no electricity from the mechanical power output from the engine, the second mode of operation further including controlling the power train such that most or all of the power output from the engine is directed to the mechanical power output.

[0005] In one embodiment, the aircraft powerplant includes an engine including a power output shaft configured to output power from the engine. The aircraft powerplant further includes a bypass fan, an electric machine, and a transmission. The transmission includes an input, a first output shaft, and a second output shaft. The power output shaft from the engine is configured to drive the input of the transmission. The first output shaft is coupled to the bypass fan. The second output shaft is coupled to the electric machine. The transmission is controllable to vary a proportion of the power from the engine between the first output shaft and the second output shaft, thereby selectively providing a majority of the power to either the first output shaft or the second output shaft.

[0006] In one embodiment, the aircraft powerplant includes an engine having a shaft. The shaft is configured to output power from the engine. The hybrid aircraft powerplant further includes a bypass fan, a first electric machine, a second electric machine, and a gear set. The gear set includes a sun gear, a plurality of planet gears connected to the planet carrier, and a ring gear. The shaft is configured to drive an input of the first electric machine and drive the sun gear. The second electric machine is configured to drive the ring gear. The bypass fan is connected to the planet carrier.

[0007] In one embodiment, a method of splitting power output from an engine between a first electric machine and a bypass fan includes controlling a gear set using a second electric machine to direct power primarily or entirely to the first electric machine in a first mode of operation. The gear set includes a sun gear connected to a power output shaft of the engine, a plurality of planet gears connected to a planet carrier, and a ring gear connected to the second electric machine. The planet carrier is connected to the bypass fan. The method includes controlling the gear set using the second electric machine and the engine to direct power to a combination of the bypass fan and the first electric machine in a second mode of operation. The method includes controlling the gear set using the second electric machine and the engine to direct power primarily or entirely to the bypass fan in a third mode of operation.

[0008] In one embodiment, a power transmission for an aircraft includes a shaft input configured to receive rotational power from an engine of the aircraft, a shaft output configured to output mechanical power to a propulsion mechanism of the aircraft, an electric output configured to output electrical power, and an electric machine configured to receive the rotational power via the shaft input and selectively generate an electrical power output via the electric output, the electrical power being selectively generated by the electric machine at least in part from the rotational power received from the engine of the aircraft via the shaft input.

[0009] In one embodiment, a powertrain for an aircraft includes a shaft input configured to receive rotational power from a turbine engine of the aircraft, a shaft output configured to output mechanical power to a propulsion mechanism of the aircraft, an electric output configured to output electrical power to an electric motor of the aircraft, an electric machine, and a control system configured to selectively cause the electric machine to generate electrical power and to output electrical power from the electric output to the electric motor. The electrical power is selectively generated by the electric machine at least a majority of the rotational power received from the engine of the aircraft via the shaft input. The control system is further selectively configured such that an amount of electrical power generated by the electric machine is less than a majority of the rotational power received from the engine while outputting the mechanical power to the propulsion mechanism of the aircraft.

[0010] In one embodiment, a method of splitting power output from an engine of an aircraft between an electric machine and a bypass fan includes receiving rotational power from the engine via an input shaft of a driveline. The method further includes selectively splitting the power output from the driveline between a mechanical power output connected to a propulsion mechanism and an electrical output of the driveline using gearing, clutches, and / or transmission components of the driveline. An amount of electrical power output at the electrical output is selectable to be a majority of the power input from the engine at the input shaft. The electrical power output at the electrical output is generated by at least one electric machine of the driveline.

[0011] In one embodiment, a power transmission for an aircraft includes a power input shaft configured to receive power from an engine of the aircraft, a propulsion mechanism, an electric machine, a power output shaft configured to output mechanical power to the propulsion mechanism, and an electric output configured to output electrical power generated by the electric machine. The power transmission is controllable to vary a proportion of power from the engine between electrical power output at the electric machine and mechanical power output at the power output shaft. The power transmission is controllable such that a majority of the power is selectively provided to either the power output shaft or the electric machine.

[0012] In one embodiment, a method of splitting power output from an engine between a first electric machine and a propulsion mechanism includes controlling the first electric machine in a first mode of operation to generate electricity using most or all of the mechanical power output from the engine. The first mode of operation further includes controlling a gear set using a second electric machine such that most or all of the mechanical power output from the engine is not directed to the propulsion mechanism. The method further includes controlling the first electric machine in a second mode of operation to generate electricity using a first substantial portion of the mechanical power output from the engine using the first electric machine and the second electric machine, and the gear set outputs a second substantial portion of the mechanical power output from the engine to the propulsion mechanism. The method further includes controlling the first electric machine in a third mode of operation to generate little or no electricity from the mechanical power output from the engine. The third mode of operation further includes controlling the gear set using the second electric machine such that most or all of the mechanical power output from the engine is directed to the propulsion mechanism.

[0013] In one embodiment, a method of splitting power output from an engine between an electric machine and a propulsion mechanism includes controlling the electric machine in a first mode of operation to generate electricity using most or all of the mechanical power output from the engine. The first mode of operation further includes controlling a gear set and / or clutch such that most or all of the mechanical power output from the engine is not directed to the propulsion mechanism. The method further includes controlling the electric machine in a second mode of operation to generate little or no electricity from the mechanical power output from the engine. The second mode of operation further includes controlling a gear set and / or clutch such that most or all of the mechanical power output from the engine is directed to the propulsion mechanism. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional side view of a turboshaft engine according to various embodiments. [Figure 2A]FIG. 1 illustrates an example of a hybrid turboshaft engine including a planetary gear set and four electric machines, according to various embodiments. [Figure 2B] FIG. 1 illustrates an example of a hybrid turboshaft engine including a planetary gear set and four electric machines, according to various embodiments. [Figure 2C] FIG. 1 illustrates an example of a hybrid turboshaft engine including a planetary gear set and four electric machines, according to various embodiments. [Figure 2D] FIG. 1 illustrates an example of a hybrid turboshaft engine including a planetary gear set and four electric machines, according to various embodiments. [Figure 3A] FIG. 1 illustrates a perspective view of an example of a bypass fan including a planetary gear set according to various embodiments. [Figure 3B] FIG. 1 is a schematic diagram illustrating an example of a bypass fan including a planetary gear set, an electric motor / generator, and a turbine engine, according to various embodiments. [Figure 4] FIG. 1 is a schematic diagram illustrating the orientation of multiple electric machines driven by a shaft of a turboshaft engine and another electric machine for driving a ring gear of a planetary gear set according to various embodiments. [Diagram 5] FIG. 5 is a cross-sectional view taken along line A in FIG. 4 showing multiple electric machines driven by a shaft of a turboshaft engine and a planetary gear set connected to a bypass fan according to various embodiments. [Figure 6] FIG. 5 is a cross-sectional view taken along line B in FIG. 4 showing an electric machine driven by a shaft of a turboshaft engine, a planetary gear set connected to a bypass fan, and an electric machine for driving a ring gear of the planetary gear set, according to various embodiments. [Figure 7] 1 is a cross-sectional view of an electric machine including a synchromesh transmission device configured to engage a rotor of the electric machine with a shaft passing through the electric machine, according to various embodiments. [Figure 8] 1 is a perspective view of an example of a synchromesh transmission device, according to various embodiments. [Figure 9] FIG. 1 is a block diagram illustrating an aircraft control system for use with a hybrid powerplant having a turboshaft engine and a planetary gear set in accordance with various embodiments. [Figure 10] 1 is a flow chart illustrating the use of a hybrid power plant having a turboshaft engine and a planetary gearset engine core in accordance with various embodiments. [Figure 11] 1 is a flowchart for engaging a shaft with a rotor of an electric motor / generator using a transmission device in accordance with an illustrative embodiment. [Figure 12] FIG. 1 is a schematic diagram illustrating a system having multiple electric motor / generators according to various embodiments. [Figure 13] FIG. 1 is a schematic diagram illustrating an air cycle for cooling a mechanical component of an aircraft, according to various embodiments. [Figure 14] FIG. 1 illustrates an example of a system including a planetary gear set and two electric machines, according to various embodiments. [Figure 15] FIG. 1 illustrates an example of a system including a planetary gear set and three electric machines, according to various embodiments. [Figure 16] FIG. 1 illustrates an example of a system including a planetary gear set and five electric machines, according to various embodiments. [Figure 17] FIG. 1 is a schematic diagram illustrating an example of a computing environment, in accordance with various embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] One aspect of aerial flight is the ability to move through the air at very high speeds. The forward motion can be created by one or more propellers, one or more fans, or multiple jet engines. As high speeds become a priority, propellers become a non-viable option and the only remaining solution can be some form of turbine engine (e.g., some type of turbine engine), commonly referred to as a turbofan or turbojet. Vertical takeoff can include hovering flight at zero or very low airspeeds. An array of lift fans, rotors, or propellers can be used to create vertical lift at low or zero airspeeds to allow the aircraft to fly vertically. For example, electrical power may be used to drive the vertical propulsion system. Thus, a power plant that can selectively provide thrust, like a turbofan, or provide a large amount of electrical power to the vertical thrust system may be desirable. Described herein is a hybrid power plant that can provide power advantageous for vertical takeoff and landing of an aircraft, and also allows for faster horizontal flight than would be possible using a forward propulsion mechanism such as a propeller. This provides an aircraft that advantageously opens up new opportunities for travel and cargo transportation, including in many cases eliminating the need for prepared runways.

[0016] Described herein are various embodiments of a parallel hybrid power plant system architecture built around a high performance turbine engine. In this solution, advantageously, the turbine functions normally by compressing outside air, adding fuel to a combustion chamber to raise the temperature and pressure, and exhausting this heated air through one or more turbines to generate usable shaft work (e.g., power). In various embodiments, various types of fuels can be used, such as jet fuel (e.g., Jet A, Jet A-1, Jet B, JP-1-JP-10, JPTS, Zip fuel, TS-1, etc.), hydrogen fuel, diesel fuel, etc., or other types of fuel based on the type of engine. This usable shaft work (e.g., power) can be advantageously used, among other things, to drive a bypass fan to generate forward thrust for the aircraft to which the apparatus is attached, and can also power very high power electric generators to provide high voltage and high power energy via electrical distribution lines to motors and / or other components, such as components adapted for vertical lift (e.g., for vertical take-off and landing (VTOL) aircraft). This combination of a turbine engine driving a ducted bypass fan to generate forward thrust for flight, and a blended transition to turbine engine driven power generation, can advantageously facilitate and power various flight modes and accessories of the aircraft in ways not previously possible. In particular, in various embodiments described herein, the shaft of a turbine engine or other engine may be capable of inputting power to a drivetrain that selectively provides power output to the bypass fan (e.g., in the case of a turbofan) or to a power bus. The drivetrain itself may include one or more electric machines capable of generating power or operating as motors (e.g., an electric machine, or emachine, as used herein, may be a generator, a generator / motor combination, an alternating current (AC) motor, a direct current (DC) motor, etc.).

[0017] In various embodiments, the electric machine, the turbine engine, and the bypass fan may all be oriented along or about a single axis or main axis. The main axis may, for example, coincide with the shaft output of the turbine engine and / or the rotational axis of the bypass fan. As such, the main axis along which the turbine engine shaft (e.g., turboshaft) runs may serve as the axis along which multiple components are oriented in parallel. In various embodiments, various components, such as the electric machine, may not be disposed in a single axis, but may be oriented along an axis parallel to the main axis. In such an example, the electric machine may receive power (electricity) from the shaft of the turbine engine along the main axis. Although various embodiments described herein include a turbine engine that includes an output shaft, any engine that includes an output shaft may be used in accordance with various embodiments described herein. That is, a particular type of engine is not required to implement various aspects of the systems and methods described herein, and the electric machines, planetary gear sets, fans generating thrust, and / or other components described herein may be used with any engine having an output shaft. Such engines may include any type of turbine engine, rotary engine, piston engine, or other type of engine.

[0018] In the aviation industry, aircraft weight may be a major concern and / or design constraint. An advantage of the parallel hybrid turbofan design, including the drivetrain described herein, is that any combination of mechanical power output and electrical output can be generated, so that the parallel hybrid turbofan, also referred to herein as a mixed turbofan, can produce two very different propulsive forces on the same aircraft with one core heat engine. In terms of thrust-to-weight ratio for atmospheric flight, ducted bypass fans, as typically used in turbofan engines, are very effective compared to other types of power plants and thus are valuable, for example, in commercial aircraft and business jets. As described herein, turbine engines driving one or more motors / generators (e.g., electric machines) can also be used to efficiently generate one or several megawatts (MW) of electrical power, which can be used in other aircraft to enable distributed electric propulsion, such as vertical take-off and landing (VTOL) aircraft. For example, an advantage of the embodiments described herein is the ability to output mechanical power and electrical power, and to split or mix such output power between mechanical power and electrical power over the full range of output power. For example, a system may output 100% or nearly 100% of the output power from an engine (e.g., turbine engine) to a mechanical output and little or no power to an electrical output. The same system may output 100% or nearly 100% of the output power from an engine (e.g., turbine engine) to an electrical output and little or no power to a mechanical output. When the output power is entirely or nearly entirely electrical power output, this means that there is little or no power to the primary forward thrust mechanism (e.g., propeller, bypass fan, or other propulsion mechanism), and therefore little or no forward thrust mechanically generated by the primary mechanical forward thrust mechanism. Furthermore, when the turbine engine selected is a turboshaft or turboprop engine, such a configuration favors the extraction of shaft power over direct thrust, and there may be little or no residual thrust, which may be advantageous for VTOL operations. This can be advantageous for certain types of aircraft, such as VTOL aircraft.Other advantages of the various embodiments herein may include improved center of gravity, efficient cooling, and control of powerplant components.

[0019] Thus, the powerplants described herein may be advantageously useful for aircraft designed for high speed travel but that also use distributed electric propulsion (DEP) or that otherwise have large power demands. Applications for DEP may include aircraft use such as VTOL, boundary layer control, blowing wings for short take-off and landing (STOL), or other unique applications of DEP. For example, a hybrid powerplant is described herein based on a turbofan engine configured to provide forward thrust via a bypass fan, with the engine being added with the ability to generate high power output for applications such as propulsion on an aircraft or other electrical applications (e.g., accessories that use large amounts of power).

[0020] FIG. 1 illustrates a side cross-sectional view of a turboshaft engine 101 according to an exemplary embodiment. In various embodiments, types of turbines or engines other than those shown in FIG. 1 may be used. In any embodiment, the engine may include an output shaft similar to shaft 105 of FIG. 1. The exemplary turboshaft engine 101 of FIG. 1 may also be referred to as a turbine engine and may have a compressor section, a combustion chamber, a turbine, and an exhaust. The turbine engine 101 may output rotational power via shaft 105. Any of the embodiments described herein may use a turbine engine as shown in FIG. 1 or other types of engines that output power via a shaft, such as shaft 105.

[0021] A turbine engine such as that of FIG. 1 may feature certain core elements including a compression section that may include one to many various stages, and may include one or more axial and / or centrifugal compressors in any combination and number. The turbine engine may further include a combustor or series of combustion chambers that introduces fuel with the compressed air to increase the temperature and pressure of the air, and one or more turbine blades that extract usable work from the high pressure and high temperature gases resulting from the combustion. The turbine stages are axial and may be any number, usually from one to four or more, depending on the turbine engine. The turbine blades may rotate any number of unique shafts that pass through the central axis of the turbine engine, and these multiple shafts do not all rotate in the same direction. Often, the high pressure turbine, which is first to contact the combustion gases, creates shaft work to power the compressor section, and a second turbine section, often called the low pressure turbine, may be used to power elements external to the core turbine engine, such as a bypass fan, a helicopter rotor, or other devices. In some turbine engines, there may be a third shaft, whereby two shafts power two separate compressor stages and may be driven by two separate turbine sections, with the third turbine section powering an element outside the core turbine engine, such as a bypass fan, a helicopter rotor, or other device. Finally, gearing may be used on one or more shafts of the turbine engine to change the characteristic revolutions per minute (RPM) or RPM range between the shafts within the core, which may rotate at an advantageously higher RPM, and the shafts used to power elements outside the core engine, which may rotate at an advantageously lower RPM. In the example of FIG. 1, gearing may be provided at the end of shaft 105 before it is connected to other components of the power plant, whereby the RPM output to another device may be lower or different than the RPM output of the turbine engine itself.

[0022] The core turbine engine concepts described herein may be applied in a variety of ways, and various terms may be used herein to refer to various applications of turbine engines. For example, one application of a turbine engine may be referred to as a turboshaft. In a turboshaft, output shaft work from a low pressure (LP) turbine section (e.g., if there are multiple turbine sections) may be provided to a flying vehicle via an output shaft. This shaft may rotate at the same RPM as the LP turbine wheel itself (referred to herein as N1), or may be geared to provide output at a different RPM. A turboshaft engine may also be used as input power to drive a gearbox in a helicopter application, and the output of that gearbox may be used to drive the main rotor of the helicopter.

[0023] Another application of turbine engines may be called turboprops. In turboprops, engine manufacturers may include a substantial gearbox in the turbine engine assembly to step down the N1 turbine output RPM to a much lower RPM and much higher torque. This output shaft may be designed to connect directly to a large propeller such as may be found on a propeller-driven commercial aircraft or small general aviation aircraft. Thus, in various embodiments described herein, the mechanical output may be directed to a propeller or similar propulsion mechanism similar to a turboprop, rather than a ducted bypass fan. In various embodiments, the mechanically driven propeller or other propulsion mechanism may also be optionally ducted. In various embodiments, the mechanical output of the system may drive one or more propellers or propulsion mechanisms using various embodiments described herein.

[0024] Vertical take-off and landing (VTOL) capabilities may be advantageous for aircraft where it is desirable to avoid the use / dependence of traditional runways. In contrast, winged aircraft that generate lift while forward may use significantly less power than aircraft that rely solely on powered lift, which may be required for a VTOL aircraft. It may therefore be desirable to design aircraft and aircraft powerplants such that the aircraft is both VTOL capable and capable of transitioning to forward flight utilizing lift generated by wings. As such, various hybrid electric powerplants are described herein that provide high power mechanical power for forward flight (e.g., fans or propellers driven by the shaft of a turbine engine) while also providing high power electrical power for the VTOL device (e.g., electric motor driven propellers driven by electricity generated from a generator based on power from the shaft of a turbine engine). By providing high levels of both mechanical power and electrical power in various flight modes, the aircraft is not only capable of VTOL, but can transition to forward flight using winged lift to provide runway independence (e.g., VTOL) while requiring less power for forward flight (e.g., based on the use of winged lift). In various embodiments, the levels of mechanical power output or electrical power output may be blended, or one of the two may be maximized while the other is minimized. While electrical power is maximized at or near maximum power output (e.g., most or all of the engine's power output is output as electrical power), the mechanical power output to the propulsion mechanisms (e.g., bypass fans, propellers, etc.) may be at or near zero, which may be advantageous for certain aircraft, such as VTOL aircraft.

[0025] The term electric machine (i.e., emachine) is also used herein to refer to either a generator, a motor, or a generator / motor combination, since an alternating current (AC) motor may also operate as a generator. Similarly, an AC generator may also operate as a motor by modifying the control and commutation strategies. In other words, an electric machine, motor, or generator referred to herein may or may not operate as either a motor and / or a generator. In various embodiments described herein, the use of such a motor / generator may not be to extract power from an on-board energy storage system and add shaft power to supplement or replace the core engine power, but rather to extract power generated by the LP turbine and transmitted by a shaft, such as shaft 105, and operate as a generator to generate very high electrical power for other uses of the aircraft (although in some modes of operation the turbofan shaft may be powered by an electric machine operating as a motor). This electrical power may be, for example, at high voltages of about 400 volts (V) or higher, or at voltages in the range of 400V to 3 kilovolts (kV). For example, nominal voltages for such systems may include 400V, 800V, 1000V, 1200V, 1500V, 2.4kV, or 3kV. However, in various embodiments, the use of electric machines may also include using power from a power source or energy storage device, such as a battery or supercapacitor, to output power from the electric machines to the shaft 105. In various embodiments, inverters or other voltage conversion devices may be used to convert the AC power output from the individual electric machines to match the nominal DC voltage of the aircraft system or bus.

[0026] Such high voltage and / or high current electrical power may be used for propulsion, lift, and / or control of an aircraft featuring one or more electric motors driving fans, propellers, or other devices. Such high voltage and / or high current may also be used for other functions of a given aircraft that require high electrical power. The total electrical power output of a turbofan, including the electric machines described herein, may be used for one or a combination of accessories or other aspects of the aircraft other than propulsion or thrust, such as, for example, auxiliary power units (APUs), air conditioning systems, avionics, high power accessories that may use one megawatt (1 MW) or more of electrical power.

[0027] In various embodiments, the motor / generator or electric machine may be located anywhere along the length of the turbofan engine inside or outside the turbofan engine housing and / or nacelle housing. In one embodiment, the motor / generator may be located a short distance forward of the bypass fan (e.g., housed within the shroud (spinner) of the turbofan), further forward from the bypass fan, located between the turbine core engine and the bypass fan, or located behind the turbine engine. As described herein, in various embodiments, multiple electric machines or motor / generators may be used in a hybrid-electric power plant for an aircraft. As such, one or more of the electric machines in such cases may be located in various locations as described herein, such as within the turbine or nacelle housing, or any other location as described herein. As also described herein, the electric machine may be oriented along the axis of the turbine engine and / or the output shaft of the turbine engine, such that the axis of the electric machine coincides with the axis of the turbine engine and shaft, or such that the axis of the electric machine does not coincide with the axis of the turbine engine and shaft, but is parallel to the axis of the turbine engine and shaft. In other words, various aspects of the driveline described herein (e.g., gears, clutches, electric machines, etc.) may be located inside or outside the engine housing or nacelle. For example, a shaft may pass through the nacelle or housing to an electric machine outside the nacelle or housing, and power may be generated by the electric machine or power may be provided to components within the nacelle or housing.

[0028] Thus, advantageously, embodiments herein provide systems, methods, and computer readable instructions for managing the power delivered by the turbine output shaft (the main outlet from the low pressure turbine as external power used to do something useful outside of the core engine). Whether this output shaft is from a turbofan engine, a turboshaft engine, or a turboprop engine (any or all of which may be referred to generally herein as a turbine engine), there may be gearing associated with the turbine engine, or the gearing may be removed, so that the shaft power is available at N1 speed (the speed at which the shaft is rotated by the LP turbine blade wheel itself). In other words, the power output by the shaft (e.g., shaft 105 in FIG. 1) may be output at the same RPM as the LP turbine section of the turbine engine rotates. This N1 shaft RPM may be in the range of, for example, 10,000 to 40,000 RPM, and in various embodiments may be, for example, about 10,000, 15,000, 20,000, 25,000, 29,000, 30,000, 35,000, 40,000, etc. Thus, the RPM output to the power blending devices described herein is the same as the RPM output of the turbine engine itself (e.g., N1 speed). In embodiments where the RPM output of the turbine engine (e.g., N1 speed) is reduced by gearing, a different RPM may be provided to the power blending devices described herein.

[0029] As described further herein below, an exemplary power blending device that splits power between mechanical power (e.g., driving a bypass fan for forward flight) and electrical power (e.g., generated by an electric machine for use in vertical flight components of an aircraft) can include a rotor of an electric machine connected to an output shaft (e.g., shaft 105 in FIG. 1 ) when the electric machine is designed to operate as a motor and / or generator. Such a rotor section can rotate at the speed of the turbine output shaft (e.g., N1 speed) in a stator outside the electric machine, which can be fixed and connected to a suitable nearby stationary reference. When the field current to the stator is low or zero, the rotor rotates but the electric machine may consume and generate zero or very little net electrical power. Thus, in this phase, the rotor of the electric machine is rotating but may not add shaft work (as a motor) or absorb shaft work (as a generator). Thus, in this state, substantially all of the available shaft power from the turbine engine passes through the electric machine and becomes available for other uses (e.g., driving a flight propeller / fan). In other embodiments, it may be desirable to prevent the rotor from rotating within the electric machine while shaft power from the turbine engine is sent to a mechanical device (e.g., a bypass fan). In such embodiments, the rotor of the electric machine may be disengaged from the shaft that outputs power from the turbine engine. As described herein below, such a transmission may be a synchromesh gear similar to those used in automotive transmissions, or other types of devices suitable for coupling or disengaging the rotor of the electric machine to a shaft passing therethrough. The electric machine may be configured in an inrunner configuration, where the rotor of the electric machine rotates within a stator. In such embodiments, the input connected to the rotor that rotates the rotor within the stator may be a shaft, as described herein. In various embodiments, the electric machine may be configured in an outrunner configuration, whereby a rotating part or element of the electric machine (e.g., the rotor) is located outside the electric machine rather than inside (e.g., the stator is inside the rotor).Such outrunner electric machines may be used in various embodiments described herein, if desired. Thus, a shaft connected to a rotating component is connected to an outer rotating component, and the shaft may have a hollow center, such as the rotor itself. A rotating component or element may also be referred to herein as either the rotor in the center of the electric machine, or the outer (or other) part of the electric machine that rotates in an outrunner electric machine design. In other words, any part of a rotating electric machine may be referred to herein as a rotating component or element, regardless of the design type of the electric machine.

[0030] FIG. 2A is a perspective view of a system 200 having a turboshaft engine 205 and three electric machines 210 configured to generate electrical power from the output of the turboshaft engine. FIGS. 2A-2D specifically depict an embodiment in which multiple electric machines are used to generate electrical power from the rotation of a shaft 255 output of the turbine engine 205. As shown in and further described with respect to FIGS. 4-6, the multiple electric machines 210 may be disposed about the shaft of the turbine engine 205 such that the axis of each electric machine 210 is parallel to the axis of the output shaft of the turbine engine 205. In various embodiments, one or more electric machines may be oriented at an angle relative to the axis of the output shaft 255 of the turbine engine 205. For example, the angle between the axis of the electric machine and the output shaft 255 can be anywhere between 0 degrees and 90 degrees, such as 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, or 90 degrees. Such angles can be facilitated, at least in part, by the use of gearing, such as bevel gears, between the output shaft of the turbine engine and the shaft of the electric machine (e.g., as further shown in FIG. 2B). The gearing can be attached to the electric machine 210 and the output shaft 255 of the turbine engine 205, such that the output shaft 255 can drive all of the electric machines 210 (e.g., as further shown in FIG. 2B). Although the examples of Figures 2A-2D and 4-6 include three electric machines driven by the output shaft of the turbine engine, numbers of electric machines other than three can be used, including embodiments in which the electric machines are disposed about the power output shaft. For example, Figures 14-16 show example embodiments in which one, two, or four electric machines, respectively, are driven by the output shaft of the turbine engine, as discussed further herein.

[0031] 2A further illustrates the housing 215, which may include gearing that connects the input of the electric machine 210 to the shaft 255 of the turbine 205. In other words, the gearing in the housing 215 connects the shaft 255 of the turbine 205 to the rotating components of the electric machine 210 such that the electric machine can generate electrical power based on the mechanical rotational input from the shaft 255 of the turbine 205. In various embodiments, a component such as a transmission or clutch between the output shaft 255 and the rotating components of the electric machine 210 can selectively engage or disengage the shaft 255 from the rotating components of the electric machine 210. In various embodiments, state currents can also be removed from the rotating components of the electric machine 210 such that they do not generate electrical power even when the respective rotating components are rotating.

[0032] Also shown in Figure 2A is an electric machine 235 that can be used to rotate / control or be rotated by a ring gear of the planetary gear set, as further shown in and described with respect to Figure 2D. Also shown in Figure 2A is a bypass fan 225 and housing 230 for the planetary gear set, as further described herein. Although Figures 2A-2D show a single planetary gear set, in various embodiments, multiple planetary gear sets can be used in series to achieve a desired mechanical output revolutions per minute (RPM) for a given application.

[0033] 2B shows a perspective view of system 200 with portions of turbine engine 205 and housing 215 hidden. Thus, spline 250 attached to shaft 255 can be connected to gearing for powering electric machines 210. In particular, spline 250 rotates with gear 248, which rotates with gear 245, each gear 245 associated with a respective one of electric machines 210. Gear 245 then rotates with gear 240, which is connected to each one of electric machines 210 or is an input / output of electric machine 210 (e.g., rotor or other rotating part of electric machine 210). Thus, spline 250 and gears 240, 245, and 248 can also be used to lower or raise the RPM between shaft 255 and the rotating parts of electric machine 210, as needed.

[0034] Figure 2C shows a perspective view of system 200 with turbine engine 205, housing 215, and electric machine 210 concealed. In particular, Figure 2C shows how electric machine 235 extends into housing 230, which can be used to control a ring gear of a planetary gear set, as further shown in and described with respect to Figure 2D. Additionally, the shaft can further have splines or gears attached to sun gear 260 (or a gear otherwise rigidly fixed to the sun gear of the planetary gear set) and rotate with sun gear 260, as described herein.

[0035] FIG. 2D further illustrates a perspective view of system 200 with turbine engine 205, housing 215, electric machine 210, and housing 230 hidden. Electric machine 235 is connected to gear 280, and the rotating components of electric machine 235 can rotate through or be rotated by gear 280. In various embodiments, the rotating components of electric machine 235 can be selectively engaged or disengaged from gear 280 by removing state currents and / or using a transmission or clutch. Gear 280 rotates with gear 285. Although not transparent or visible in FIG. 2D, a rigid member connects gear 285 to ring gear 270 of a planetary gear set, allowing each of the rotating components of electric machine 235, gear 280, gear 285, and ring gear 270 to rotate together. This gearing allows the RPM between ring gear 270 and gear 280 to be increased or decreased as needed.

[0036] The sun gear 260 may rotate with the planet gears 265, as described further herein. The planet gears 265 may be connected to a planet carrier 275, which is rigidly connected to the bypass fan 225. In this manner, as the planet carrier 275 rotates, the bypass fan 225 also rotates, as described further herein.

[0037] 3A is a perspective view of an example system 300 having a bypass fan 305 including a planetary gear set according to an exemplary embodiment. The hybrid engine described herein can split power between a mechanical output (e.g., to drive the bypass fan 305) and an electrical output (e.g., the electric machine 210 of FIGS. 2A and 2B). One component can be used in conjunction with another component to achieve the required split or balance of power output types. In particular, the planetary gear set can act as an on / off switch to obtain thrust from the bypass fan, as described further below.

[0038] For electrical output (e.g., via electric machine 210 of FIGS. 2A and 2B), the electric machine may be configured to generate electrical power based on an input from the turbine engine output shaft based on whether a field current is applied to a stator of the electric machine and / or whether a clutch, transmission, or the like connecting the turbine engine output shaft and the shaft of the electric machine is engaged as described later herein. Mechanical output (e.g., to drive bypass fan 305) may be driven and turned on / off using a planetary gear set as described further herein.

[0039] The gear set includes a sun gear 310 that rotates with planetary gears 315. The sun gear 310 may be connected to an output shaft of a turbine engine, such as shaft 105 of FIG. 1 or output shaft 255 of turbine engine 205 of FIGS. 2A-2D. The planetary gears 315 may be connected to a planet carrier 320, which may also be connected to a bypass fan 305. The planetary gears 315 rotate with a ring gear 325. The ring gear 325 may be driven by and connected to another electric machine (not shown in FIG. 3A).

[0040] In this manner, power is input to (or absorbed from) the gear set by the turbine engine output shaft via the sun gear 310 and / or by the electric machine via the ring gear 325. In this manner, the electric machine rotates the ring gear 325, causing the planet gears 315 to rotate at a speed such that (i) the planet carrier 320 does not rotate (and thus the bypass fan 305 does not rotate) or (ii) the planet carrier 320 rotates (and thus the bypass fan 305 rotates). In this manner, the bypass fan 305 can be switched on or off, or the speed of the bypass fan adjusted, depending on the speed of the output shaft connected to the sun gear 310, based on the control of the electric machine connected to the ring gear 325.

[0041] Similarly, as long as the output speed of the turbine engine shaft is controllable, the planetary gear set (and the speed of the bypass fan) of FIG. 3A may also be controllable based on the controllable output of the turbine engine. For example, the revolutions per minute (RPM) of the turbine engine may be controllable in a range from about 82% of the target N1 speed to 105% of the target N1 speed. In various embodiments, at speeds above the target N1 speed or below the target N1 speed, the turbine engine may shut down or it may be impractical or impossible to operate without damaging the turbine engine. In other words, the speed at which the bypass fan 305 rotates (or does not rotate) may be controlled using the turbine engine and, for example, an electric machine connected to the sun gear 310 and the ring gear 325, respectively. In this way, the bypass fan 305 is turned off when the sun gear 310 rotates, the planet carrier 320 stops, and the ring gear 325 is driven by an electric machine connected to the ring gear 325 and rotates at the correct speed based on the RPM of the sun gear 310. Thrust is output from the bypass fan 305 when an electric machine connected to the ring gear 325 reduces the RPM / rotational speed of the ring gear 325 causing the planet carrier 320 to move, and therefore the bypass fan 305 .

[0042] 3B is a schematic diagram illustrating a cross section of a system 330 including a bypass fan 370 and a planetary gear set, a first electric machine 345, a second electric machine 375, and a turbine engine 335, according to an example embodiment. In particular, the turbine engine 335 includes an output shaft 340 that passes through the electric machine 345 and connects to a sun gear 350 of the planetary gear set. As described with respect to FIG. 3A, the sun gear 350 rotates with the planet gears 335, which rotate with the ring gear 360. The planet gears 355 are also connected to a planet carrier 365, which is connected to the bypass fan 370. The output of the electric machine 375 may be connected to a gear 380 that rotates with the ring gear 360, such that the rotation of the planet carrier 365, and therefore the bypass fan 370, may be controlled as described herein. In various embodiments, as described herein, the rotor of the electric machine 345 may rotate even when the electric machine 345 is not producing power from the output shaft 340. However, in other embodiments, a transmission 385 (such as a synchronous gear or a clutch) may be used to engage or disengage the rotor of the electric machine 345 from the shaft 340. In this manner, while the transmission 385 is disengaged, the shaft 340 rotates within the electric machine 345, but the rotor of the electric machine 345 does not rotate. Although one particular possible configuration is shown in FIG. 3A, other arrangements of similar, additional, or different components as shown in FIG. 3A may also be used.

[0043] By using gear sets as shown in Figures 3A and 3B, power blending can be achieved and different modes of power output can be achieved. For example, in mode E (e.g., electrical power is desired), the planet carrier 365 attached to the bypass fan 370 does not rotate. Since the sun gear 350 is rotating, this necessarily means that the planet gears 355 are rotating on their respective individual axes. As long as the ring gear 360 is rotating in the opposite direction at an RPM determined by the gear ratio of the planetary gear set, the planet gears 355 will rotate on their respective axes, but the planet carrier 365 will not rotate and the bypass fan 370 will stop. In various embodiments, the ring gear 360 may rotate naturally as a result of the planet carrier 365 being secured in some manner, such as by a pin, lock, band clutch, or other type of locking mechanism connected to a stationary reference structure. The pin, lock, band clutch, or other type of locking mechanism may be electronically controlled, such as by a controller or processor, whereby the locking of the planet carrier 365 may be accomplished by the control system of the aircraft or hybrid power plant. Assuming the planet carrier 365 and bypass fan 370 are not locked in any way, maintaining Mode E may require driving the ring gear 360 in the appropriate direction, at the appropriate speed, and with the appropriate power to keep the planet carrier 365 in a stable position even while the sun gear 350 is rotating at high speeds (e.g., based on the speed of the output shaft 340). This may be advantageously accomplished by using a separate electric machine 375. The electric machine 375 may thus be controlled in a direction and at RPM suited for this purpose.

[0044] In mode T (e.g., forward thrust is desired), the ring gear 360 may be stopped and the planet carrier 365 rotates at an RPM determined by the ratio of radii between the sun gear 350 and the planet gears 355. This rotation of the planet carrier 365 attached to the bypass fan 370 causes the bypass fan 370 to absorb power applied by the turbine output shaft 340 through the sun gear 350, creating an air flow that leads to forward thrust. In various embodiments, the motion of the ring gear 360 may be stopped by applying a field current to the electric machine 375 or other mechanical or controllable electromechanical pins, locks, band clutches, brakes, or other types of locking mechanisms. In various embodiments, a locking mechanism, such as an electromechanical pin, lock, band clutch, brake, or other type of locking mechanism, may be used without the use of the electric machine 375 (e.g., in various embodiments, there may not be a second electric machine outputting power to or absorbing power from the gears of the planetary gear set).

[0045] Such an arrangement of a turbine engine, a first electric machine (e.g., motor / generator) including a transmission (synchro and dog ring engagement system and / or clutch as further shown in and described with respect to FIGS. 7 and 8), a planetary gear set, a second electric machine connected to a ring gear of the planetary gear set, and a fan including a hub connected to a planet carrier may be employed on an aircraft to provide advantageous performance characteristics. This performance includes the ability to engage the system in synchromesh dog gear engagement in addition to mode E to obtain maximum output of power from the first electric machine when the rotational speed of the fan hub is zero or close to zero. In this arrangement, substantially all of the power generated by the turbine engine is converted to electrical power (current). In mode T with the dog gear disengaged, the advantageous performance characteristic is the ability to transfer substantially all of the power from the turbine output shaft to the fan hub to drive the bypass fan to generate forward thrust to support winged flight. In this mode, it may be particularly advantageous to eliminate the flow of electrical power to the motor / generator to provide maximum power to the fan to achieve maximum forward thrust and speed.

[0046] A power blend between modes E and T, such as mode B (e.g., a desired blended power), and therefore a power blend between electrical generation and mechanical forward thrust, may be particularly advantageous for certain aircraft. To achieve the blending, an electric machine connected to the ring gear (e.g., electric machine 375 connected to ring gear 360 in FIG. 3B) may be controlled to drive the ring gear at any intermediate speed, rather than zero (for mode E) and maximum speed (for mode T), as determined by the control strategy and flight conditions (e.g., based on desired electrical and mechanical power outputs). Such power blending allows the aircraft to benefit from forward thrust while simultaneously generating less than the maximum amount of electrical power available. In this blended mode, the electric machine connected to the ring gear may also be operated as a generator, given the need to apply a resistive torque to the ring gear. Thus, the electric machine connected to the ring gear generates electrical power that can be output (e.g., added to the aircraft's high voltage bus) and used for aircraft operation, battery charging, aircraft accessories, or other advantageous use of this generated power. FIG. 3B shows a particular configuration in which the sun gear is mounted to the turbine output shaft, the planetary gears are mounted to a carrier with a bypass fan, and the ring gear is connected to an electric machine, although other configurations for using a planetary gear set or other power split device may also be used.

[0047] 3B also shows the electric machine 345 disposed between the turbine engine 335 and the planetary gearset. However, other configurations may be used in various embodiments. For example, the output shaft 340 may extend from the other end of the turbine engine 335, and the electric machine 345 may be disposed aft of the turbine engine 335 (e.g., such that the turbine engine 335 is disposed between the planetary gearset and the electric machine 345). In another example, the output shaft 340 may extend forward of the planetary gearset, and the electric machine may be disposed forward of the planetary gearset (e.g., such that the planetary gearset is disposed between the first electric machine 345 and the turbine engine 335).

[0048] Figure 4 is a schematic diagram showing the orientation of multiple electric machines 415, 420, 425 driven by a shaft 405 of a turboshaft engine and another electric machine 410 for driving a ring gear of a planetary gear set according to an exemplary embodiment. Figure 5 is a cross-sectional view taken along line A in Figure 4 and shows multiple electric machines 420, 425 driven by a shaft 405 of a turboshaft engine and a planetary gear set connected to a bypass fan 305 according to an exemplary embodiment. Figure 6 is a cross-sectional view taken along line B in Figure 4 and shows an electric machine 415 driven by a shaft 405 of a turboshaft engine, a planetary gear set connected to a bypass fan 305, and an electric machine 410 for driving a ring gear 325 of the planetary gear set according to an exemplary embodiment.

[0049] More specifically, Figures 4-6 show how, instead of a single electric machine (as in Figure 3B), multiple electric machines 415, 420, 425 driven by gears 605, 505, and 515, respectively, can be used to generate power from the output shaft of a turbine engine. In particular, the output shaft 405 of the turbine engine can be used to drive a bevel drive gear set including a gear 510 rigidly connected to the shaft 405 or a portion of the shaft 405, which drives the gears 505, 515, 605, which in turn drive multiple electric machines 415, 420, 425, respectively, in an arrangement as shown in Figure 5. This can be particularly advantageous when the available power of the turbine output shaft is higher than the available power ratings of the individual electric machine generators. For example, the power available at the turbine output shaft is 1.5 megawatts (MW), but the available machine power rating is only 500 kilowatts (kW). In another configuration, the total turbine power output is 5 MW, but each available generator has a power rating of 1 MW (and, for example, five electric machines may be used). In various embodiments, various levels of total power output may thus be achieved, such as from 250 kW to 30 MW of power from a single turbine engine (multiple powerplants described herein may also be used in a single aircraft to achieve various levels of power output, or to provide mechanical power to multiple propulsion mechanisms of the aircraft). For example, the output of a single powerplant system described herein may output 250 kW, 370 kW, 400 kW, 500 kW, 1 MW, 5 MW, 10 MW, 15 MW, 20 MW, 23 MW, or 30 MW (either electrical or mechanical energy). As such, the amount of electrical power that may be output by the powertrain (e.g., one or more electric machines that are part of the powertrain described herein) may be as high as 250 kW to 30 MW of electrical power as the powertrain described herein for a single turbine engine or mixed turbofan powerplant (multiple powerplants described herein may also be used in a single aircraft as needed to achieve different levels of electrical power output or to provide mechanical power to multiple propulsion mechanisms on the aircraft).For example, the output of a single mixed turbofan or powertrain system described herein may output 250 kW, 370 kW, 400 kW, 500 kW, 1 MW, 5 MW, 10 MW, 15 MW, 20 MW, 23 MW, or 30 MW (either electrical or mechanical energy). Although the maximum capacity output of the engine, and therefore the output of the associated powertrain, may be at these levels, the engine may not always operate at maximum capacity or maximum throttle. For example, the engine may operate at different throttles, which may be expressed as a percentage of the power output available at maximum throttle. For example, the engine may be throttled anywhere from 0% to 100%. Whenever the engine is not at maximum throttle, various embodiments herein may convert any power output by the engine into a mix or blend of mechanical power and electrical power. Thus, even when the engine is at a high level of throttle (e.g., 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, etc.), the total power output can be split or mixed between mechanical and electrical outputs at various mix levels as described herein, including cases where most or all of the power is allocated to only one of the electrical or mechanical outputs. In addition to arranging the electric machines about the power shaft in a planetary configuration as shown in Figures 4-6, additional electric machines can be added or instead placed at other locations along the length of the shaft output from the turbine engine. For example, the shaft can have multiple gearings similar to gear 510, and electric machines at various locations along the shaft can receive power from shaft 405.

[0050] Another advantage of an arrangement such as that of FIGS. 4-6 is that the bevel drive gear set including gears 505, 510, 515, and 605 can be used to change the input RPM compared to the N1 speed to provide a more favorable input to the motor / generator unit (e.g., substantially reduce or increase the driven RPM) depending on the size / rating, etc. of the electric machine. In other words, the gearing between shaft 405 and electric machines 415, 420, 425 can also reduce or increase the RPM from the shaft to the input to electric machines 415, 420, 425 as needed. This bevel drive gear configuration can be used to drive one, two, three, four, five, or more motor / generator units in the same area of ​​the hybrid power plant. These motor / generators may or may not be identical to each other. They may all be energized with field current at a given time to generate motor / generator torque for simultaneous operation, even if they are directly geared to generate rotation at all times. They may all be selectively disengaged / engaged from their respective bevel gears (e.g., using a synchromesh transfer cone and dog gear arrangement, or other suitable connection such as a clutch). For example, it may be advantageous to engage multiple motor / generators in stages, such as one at a time, until the full number of engaged motors / generators is reached. All of the motors / generators in this arrangement may be directly linked to the bevel drive gears to be engaged by applying a field current to their respective stators, or may use a synchromesh transfer engagement to limit unnecessary power losses when the mode of operation does not require the use of the motors / generators to consume or generate power.

[0051] Figure 5 is a cross-sectional view taken along line A in Figure 4 and shows a bevel drive gear set including gear 510 which drives gears 505 and 515 to drive multiple electric motor / generators 420 and 425. Gear 510, and sun gear 310 of the planetary gear set, can be machined, for example, on the N1 turbine output shaft (or a shaft connected to the N1 turbine output shaft via a clutch, transmission, gearbox, etc.). Figure 5 also shows planetary gear 315, ring gear 325, and fan 305.

[0052] The various components of the hybrid power plant system described herein (e.g., components of any of Figures 1-8), including the turbine engine, motor / generator, power blending planetary gear set connected to a ring gear and associated motor / generator, fan hub / planet carrier, and / or bypass fan, may be advantageously arranged in a designed duct or nacelle. This arrangement of components and designed ducts may be mounted in an aircraft with appropriate inlet and outlet flow treatments to support efficient operation. The ducts may also be housed in a nacelle designed to be mounted in the aircraft fuselage, wing, or other suitable location such that the nacelle is in contact with the surrounding airflow at its exterior surface. Whether internally mounted or in a nacelle, the airflow may be managed in front of the bypass fan and then routed downstream through the bypass fan to maximize net forward thrust. Such nacelles, including ducted fans, may be optimized to maximize mass flow, pressure rise, or the most advantageous combination of these two factors in relation to a particular aircraft design and required thrust. The planetary gear set provides additional flexibility in bypass fan RPM and turbine output shaft RPM for maximum adaptation to a specific mission or aircraft style (e.g. bypass fan RPM can be adjusted / customized without changing the turbine engine output RPM).

[0053] Various specific embodiments of systems and methods that can be used to split or mix power between an electrical power output (e.g., generated by an electric machine) and a mechanical power output (e.g., thrust via a bypass fan) are described with respect to the use of planetary gear sets, although other configurations, gear sets, clutches, transmissions, or other methods and systems for splitting or mixing may be used in various embodiments. Additionally, planetary gear sets similar to those shown and described herein (e.g., with respect to FIGS. 2-6) may be used in various embodiments in configurations other than those described herein. For example, instead of the turbine output shaft being connected to the sun gear, the planet carrier being connected to the bypass fan, and the ring gear being connected to the electric machine as in FIGS. 2-6, various embodiments may include the bypass fan being connected to the ring gear, the electric machine being connected to the planet carrier, and the turbine output shaft being connected to the sun gear. Thus, planetary gear sets or other components that split or mix power between the mechanical and electrical outputs of the power plant in various configurations may be used as part of various embodiments to achieve the power split / mixing functions described herein.

[0054] For example, the configuration of FIGS. 4-6 shows electric machines 415, 420, and 425 disposed between the engine and the planetary gearset. However, in various embodiments, other configurations may be used. For example, output shaft 405 may extend from the rear end of the engine, and any or all of electric machines 415, 420, and / or 425 may be disposed aft of the engine (e.g., the engine is disposed between the planetary gearset and one or more electric machines 415, 420, and / or 425). In another example, output shaft 405 may extend forward of the planetary gearset, and any or all of electric machines 415, 420, and / or 425 may be disposed forward of the planetary gearset (e.g., the planetary gearset is disposed between one or more electric machines 415, 420, and / or 425 and the engine).

[0055] In various embodiments, a planetary gear set or other component that can be used to at least partially split or mix the power may be referred to as a power transmission. Thus, as with other embodiments herein, a power transmission may have a power input shaft (e.g., the output of a turbine engine), a first output shaft (e.g., for power output to an electric machine to generate electrical power), and a second output shaft (e.g., for mechanical power output when the second output shaft is directly or indirectly connected to a bypass fan). Thus, any configuration of a power transmission capable of transmitting different amounts of power output through at least two different shafts, at least one shaft for mechanical power output and at least one shaft for electrical power output, may be used in various embodiments. In particular, the power output through the different shafts may be a portion, all, or none, or a majority of the total power input from the engine. In this way, both shafts may have a significant power output therethrough (e.g., above nominal power for powering some low power accessories). In other words, the power transmission device is controllable to vary the ratio of power from the engine between the first and second output shafts, thereby selectively providing a majority of the power to either the first or second output shaft. A variety of balances of power output between the mechanical and electrical output shafts can be achieved such that any balance between zero and one hundred percent (0%-100%) of the power output by the system can be output to either the mechanical power output shaft or the electrical shaft.The ranges may be, for example, approximately (wherein the first number indicates the percentage of engine power output output by the driveline through the mechanical output shaft(s) and the second number indicates the percentage of engine power output output by the driveline through the electric machine(s)) 100 / 0, 99.5 / 0.5, 99 / 1, 98.5 / 1.5, 98 / 2, 97.5 / 2.5, 97 / 3, 96.5 / 3.5, 96 / 4, 95.5 / 4.5, 95 / 5, 94.5 / 5.5, 94 / 6, 93.5 / 6.5, 93 / 7, 92.5 / 7.5, 92 / 8, 91.5 / 8.5, 91 / 9, 90.5 / 9.5, 90 / 10, 89 / 11, 98.5 / 1.5, 98 / 2, 97.5 / 2.5, 97 / 3, 96.5 / 3.5, 96 / 4, 95.5 / 4.5, 95 / 5, 94.5 / 5.5, 94 / 6, 93.5 / 6.5, 93 / 7, , 88 / 12, 87 / 13, 86 / 14, 85 / 15, 80 / 20, 75 / 25, 70 / 30, 65 / 35, 60 / 40, 55 / 45, 50 / 50, 45 / 55, 40 / 60, 35 / 65, 30 / 70, 25 / 75, 20 / 80, 15 / 85, 14 / 86, 13 / 87, 12 / 88, 11 / 89, 10 / 90, 9.5 9.5, 1 / 99, 0.5 / 99.5, or 0 / 100. In various embodiments, a controller or processor such as described herein with respect to FIG. 9 may be used to control the percentage mix of power output between mechanical and electrical power, as described herein.

[0056] FIG. 14 illustrates an example system 1400 including a planetary gear set and two electric machines, according to various embodiments. The system 1400 illustrates an example diagram of the system 1400 similar to FIG. 4, except that only two electric machines are shown. The electric machine 1410 can be similar to the electric machine 410 of FIG. 4, and the shaft 1405 can be similar to the shaft 405 of FIG. 4. Instead of having three electric machines that can be driven by the shaft 1405, FIG. 14 illustrates a single electric machine 1415 that can be driven by the shaft 1405 via a gear 1420. Thus, power in the example system 1400 can be mixed between the mechanical output (e.g., to a bypass fan, not shown, via the shaft 1405 and the planetary gear set, not shown) and the electric machine 1415. In the example of FIG. 14, the electric machine 1415 is located on the opposite side of the electric machine 1410. 14 can be positioned at a 180 degree position when the electric machine 1410 is positioned at a 0 degree angular position relative to the shaft 1405. In various embodiments, the electric machine 1415 can be positioned at an angular position between 0 degrees and 360 degrees relative to the shaft 1405, such as about 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170 degrees, 17 ... 5°, 180°, 185°, 190°, 195°, 200°, 205°, 210°, 215°, 220°, 225°, 230°, 235°, 240°, 245°, 250°, 255°, 260°, 265°, 270°, 275°, 280°, 285°, 290°, 295°, 300°, 305°, 310°, 315°, 320°, 325°, 330°, 335°, 340°, 345°, 350°, 355°, or 360°. In various embodiments, the electric machine 1410 may be positioned at different positions relative to the shaft 1405, similar to that described in the previous sentence with respect to the electric machine 1415.In various embodiments, the electric machine 1410 and the electric machine 1415 may also be located at different lateral positions along the shaft 1405 so that a cross-sectional plane similar to FIG. 14 of the system does not intersect both the electric machines 1410 and 1415. In an embodiment similar to FIG. 14 where there is a single electric machine configured to generate power from the engine output, the single electric machine may have a shaft through which the shaft 1405 passes (e.g., similar to the configuration shown in FIG. 7). In such a configuration, the electric machine and the shaft may share the same centerline or axis.

[0057] FIG. 15 illustrates an example system 1500 including a planetary gearset and three electric machines, according to various embodiments. System 1500 illustrates an example diagram of system 1500 similar to that of FIG. 4, except that only two electric machines 1515 and 1525 are shown. Electric machines 1515 and 1525 may be similar to electric machines 420 and 425 of FIG. 4, shaft 1505 may be similar to shaft 405 of FIG. 4, and electric machine 1510 may be similar to electric machine 410 of FIG. 4. Instead of having three electric machines that may be driven by shaft 1405 as in FIG. 4, FIG. 15 illustrates two electric machines 1515 and 1525 that may be driven by shaft 1405 via gears 1520 and 1530, respectively. Thus, power in the example system 1500 may be mixed between the mechanical output (e.g., to a bypass fan, not shown, via shaft 1505 and a planetary gearset, not shown) and electric machines 1515 and 1525. In the example of Figure 15, the electric machines 1515 and 1525 are positioned opposite each other. In other words, when the electric machine 1410 is at a 0 degree angular position relative to the shaft 1405, the electric machine 1515 of Figure 15 may be positioned at a 270 degree position and the electric machine 1525 of Figure 15 may be positioned at a 90 degree position. The electric machines 1515 and 1525 may be positioned opposite each other to balance the weight within the system 1500.In various embodiments, either of the electric machines 1515 and 1525 may be rotated relative to the shaft 1505 from 0 degrees to 360 degrees, for example, at about 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170 degrees, 175 ... It may be positioned at other positions including 170 degrees, 175 degrees, 180 degrees, 185 degrees, 190 degrees, 195 degrees, 200 degrees, 205 degrees, 210 degrees, 215 degrees, 220 degrees, 225 degrees, 230 degrees, 235 degrees, 240 degrees, 245 degrees, 250 degrees, 255 degrees, 260 degrees, 265 degrees, 270 degrees, 275 degrees, 280 degrees, 285 degrees, 290 degrees, 295 degrees, 300 degrees, 305 degrees, 310 degrees, 315 degrees, 320 degrees, 325 degrees, 330 degrees, 335 degrees, 340 degrees, 345 degrees, 350 degrees, 355 degrees, or 360 degrees. In various embodiments, the electric machine 1510 may be positioned at different positions relative to the shaft 1405, similar to that described in the previous sentence with respect to the electric machines 1515 and 1525. In various embodiments, electric machine 1410 and any of electric machines 1515 and 1525 may be positioned at different lateral positions along shaft 1505, such that a cross-sectional plane of the system similar to that of FIG. 14 does not intersect all of electric machines 1510, 1515, and / or 1525 at the same time.

[0058] FIG. 16 illustrates an example system 1600 including a planetary gear set and five electric machines, according to various embodiments. The system 1600 illustrates an example diagram of the system 1600 similar to that of FIG. 4, except that four electric machines 1620, 1630, 1635, and 1645 are shown. The electric machines 1620, 1630, 1635, and 1645 may be similar to any of the electric machines 415, 420, and 425 of FIG. 4, the shaft 1605 may be similar to the shaft 405 of FIG. 4, and the electric machine 1610 may be similar to the electric machine 410 of FIG. 4. Instead of having three electric machines that may be driven by the shaft 1405 as in FIG. 4, FIG. 16 illustrates four electric machines 1620, 1630, 1635, and 1645 that may be driven by the shaft 1505 via gears 1615, 1625, 1640, and 1650, respectively. Thus, power in the example system 1600 may be mixed between the mechanical output (e.g., via shaft 1605 and planetary gear set, not shown, to a bypass fan, not shown) and the electric machines 1615, 1625, 1640, 1650. In the example of FIG. 16, pairs of electric machines 1615, 1625, 1640, 1650 are positioned generally opposite each other and generally evenly spaced. In other words, when electric machine 1610 is positioned at a 0 degree angular position relative to shaft 1605, electric machine 1620 of FIG. 16 may be positioned at a 315 degree position, electric machine 1630 of FIG. 16 may be positioned at a 225 degree position, electric machine 1635 of FIG. 16 may be positioned at a 135 degree position, and electric machine 1645 of FIG. 16 may be positioned at a 45 degree position. The electric machines 1615 , 1625 , 1640 , and 1650 may be oriented to balance the weight within the system 1600 .In various embodiments, any of the electric machines 1615, 1625, 1640, and 1650 may be rotated relative to the shaft 1605 from 0 degrees to 360 degrees, for example, at about 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 170 degrees, 175 ... In some embodiments, the optical axis may be positioned at other positions including 165°, 170°, 175°, 180°, 185°, 190°, 195°, 200°, 205°, 210°, 215°, 220°, 225°, 230°, 235°, 240°, 245°, 250°, 255°, 260°, 265°, 270°, 275°, 280°, 285°, 290°, 295°, 300°, 305°, 310°, 315°, 320°, 325°, 330°, 335°, 340°, 345°, 350°, 355°, or 360°. In various embodiments, the electric machine 1610 may be positioned at different locations relative to the shaft 1605, similar to that described in the previous sentence with respect to the electric machines 1615, 1625, 1640, and 1650. In various embodiments, the electric machine 1610 and any of the electric machines 1615, 1625, 1640, and 1650 may be positioned at different lateral locations along the shaft 1605, such that a cross-sectional plane similar to FIG. 16 of the system does not intersect all of the electric machines 1610, 1615, 1625, 1640, and / or 1650 simultaneously.

[0059] As discussed above, different embodiments may use different numbers of electric machines. This allows the size of the electric machines used to vary depending on the power requirements of the aircraft and / or the power output of the engines in the system. For example, for a given engine power output, a larger electric machine 1415 in FIG. 14 may be used, or two to four smaller electric machines may be used on the same engine according to each of FIGS. 4, 15, and / or 16. Similarly, for a given electric machine, fewer electric machines may be used for an engine with a smaller total power output, while more of the same given electric machine may be used for a larger engine with a larger total power output. Thus, various embodiments provide different tailored embodiments for different power requirements, space constraints, orientations, etc., as needed.

[0060] Figure 7 is a cross-sectional view of a system 700 having an electric machine including a synchromesh transmission device configured to engage a rotor 715 of the electric machine by a shaft 705 passing through the electric machine, according to an example embodiment. Figure 8 is a perspective view of an example synchromesh transmission device 800, according to an example embodiment.

[0061] In cases where the design of a given motor / generator (e.g., electric machine) makes it impossible or unfavorable to eliminate the field current and drive the net torque to zero (e.g., significant energy would be absorbed by the electric machine and generated as heat, damaging the electric machine over time), a transmission or clutch can be used to limit the power consumed by the motor / generator and allow all or substantially all of the power on the shaft to pass through the electric machine and be output to other components of the system (e.g., a planetary gear set for output to a bypass fan). For example, in FIG. 7, an arrangement is shown showing that rotor 715 may be optionally coupled to turbine output shaft 705, thereby optionally connecting and disconnecting rotor 715 using a synchro ring and dog gear drive system. Synchro cone and dog gear 730 may be designed to rotate at the same speed as shaft 705, as it is always driven by splines 735 on shaft 705.

[0062] In one operating condition, the synchro cone and dog gears 730 are spaced apart from but adjacent to the electric motor rotor 715, so that there is no torque or power transfer from the turbine output shaft 705 to the rotor 715. The rotor 715 may be stopped (zero rotational speed) or may rotate at a very low RPM due to the resistive friction of the bearings 720 that ride on the shaft 705, but may consume little or no power because the rotational speed is close to zero. This may be a desirable condition, such as if the power of the turbine output shaft 705 is used for another purpose, such as driving a bypass fan.

[0063] In a second operating state, the synchro cone with dog gear arrangement 730 is pressed against a mating cone 725 attached to the rotor 715 of the motor by a controllable actuator. Friction between these two cones 730 and 725 causes their RPMs to match until the dog gear drive of the synchro cone with dog gear 730 can engage. When the dog gear engages, the relative motion between the two cones 730 and 725 stops and the drive from the turbine output shaft 705 to the rotor is direct. That is, the two cones 730 and 725 can rotate at the same speed (e.g., RPM) and the turbine output shaft 705 can provide power to or receive power from the motor / generator. This is desirable when the intended power flow involves the generator generating power for use by the aircraft and output power from the turbine output shaft 705 being transferred to the motor / generator as the rotor 715 rotates relative to the stator 710 of the electric machine. A specific example of a synchromesh transmission device 800 that can be used is shown in FIG. 8.

[0064] 7 and 8 show examples of methods for engaging and disengaging the rotor of an electric machine from a shaft, such as a turbine output shaft. Other components and methods for engaging and disengaging the rotor of the electric machine from a shaft (e.g., a clutch without a synchro cone or a simple dog gear) may be used in addition or instead in various embodiments. Furthermore, the methods and systems for engaging and disengaging the rotor of a generator from a shaft may be used with any electric machine described in accordance with embodiments herein. For example, in FIGS. 4-6, some or all of electric machines 410, 415, 420, and / or 425 may have a transmission or clutch for engaging and disengaging each electric machine from the respective shaft passing therethrough.

[0065] As used herein, a transmission or power transmission device may further be used to mean any component that receives power from an engine through a first shaft and splits the power into a mechanical power output on a second shaft and an electrical power output. For example, any of a gear set, clutch, electric machine, locking mechanism, shaft, etc. may be assembled or packaged as a transmission device that receives mechanical power from an engine and outputs mechanical power, electrical output, or a combination of the two as needed. For example, Figures 2A-2D, 3A, 3B, 4-8, 12, and 14-16 show components that may be part of a power transmission device described herein to mix or adjust the power output between a mechanical output and an electrical output, including components such as shafts, clutches, locking mechanisms, electric machines, etc. Furthermore, as described herein, such a power transmission device may also receive electrical power (e.g., from a battery pack) and use the electrical power to further output additional mechanical power.

[0066] FIG. 9 illustrates a block diagram 900 representing an aircraft control system for use with a hybrid powerplant having a turboshaft engine and a planetary gear set, according to an exemplary embodiment. The aircraft control system 900 can be used, for example, to implement one or more of the various operating modes of the hybrid powerplant described herein. The engine 920 of the system 900 can be the same as or similar to any of the turbine engines (e.g., turboshaft, turbofan, etc.) described herein. The bypass fan 945 can be the same as or similar to any of the bypass fans described herein. The first generator / motor 925 can be the same as or similar to any of the electric machines described herein that are powered from the shaft of the turbine engine 920. The second generator / motor 930 can be the same as or similar to any of the electric machines described herein that are used to control and / or power the ring gear of the planetary gear set. The synchromesh transmission 935 can be the same as or similar to any of the synchromesh transmissions described herein, or can be a different type of clutch or transmission described herein.

[0067] The aircraft control system 900 may further include one or more processors or controllers 905 (hereafter controller 905), memory 910, power I / O 940, accessories 945, one or more sensors 915, one or more propulsion mechanisms 950, and a power source such as a battery 955. The connections in FIG. 9 show control signal related connections between components of the aircraft control system 900. Other types of connections not shown in FIG. 9 may exist between various aspects of the aircraft and / or aircraft control system 900 to provide power such as high voltage (HV) or low voltage (LV) power for the aircraft. The power I / O 940 may physically connect the generator / motor 925 to one or more buses or wiring of the aircraft so that power can be distributed throughout the aircraft. The power I / O 940 may be or include sensors such as voltage or current sensors configured to measure aspects of the power flowing into or out of the generator / motor 925 and / or generator / motor 930. Thus, controller 905 may be configured to monitor and / or control the power flowing into or out of generator / motor 925 and / or generator / motor 930 .

[0068] The memory 910 may be a computer readable medium configured to store instructions. Such instructions may be computer executable code executed by the controller 905 to implement various methods and systems described herein, including various modes of use of the hybrid power plant described herein, and combinations or particular sequences of those modes. The computer code may be written such that various methods of implementing different modes of the hybrid power plant described herein are automatically implemented based on various inputs, for example, indicative of a particular flight phase (e.g., landing, takeoff, cruise, etc.) or particular sensor conditions (e.g., altitude, temperature, air pressure, fuel level, operational status of various components on board the aircraft, etc.). In various embodiments, the computer code may be written to implement various modes herein based on inputs from a user or pilot of the aircraft or aerospace vehicle, or may be implemented based on a combination of user inputs and automatic implementations based on non-human inputs (e.g., inputs from sensors on or off the aircraft, inputs based on a planned flight plan, etc.). The controller 905 may be powered by an aircraft or aerospace vehicle power source, such as a generator / motor 925 and / or a generator / motor 930, one or more batteries 955, power I / O 940, an aircraft power bus powered by any power source, and / or any other available power source.

[0069] The controller 905 may be in communication with each of the components in Figure 9. In this manner, the components of the hybrid power plants described herein may be controlled to implement the various modes described herein.

[0070] The sensors 925 may include various sensors for monitoring various components of the hybrid power plant. Such sensors may include, for example, temperature sensors, tachometers, fluid pressure sensors, voltage sensors, current sensors, status sensors (for determining the current state of the synchromesh transmission 935, the current state of any gearboxes, etc.), or other types of sensors. For example, voltage and / or current sensors may be used to inform the motor / generator functions and settings, the synchromesh transmission 935 of the selected state, or adjustments to other components of the system. The status sensors may also indicate the particular mode in which the hybrid power plant is to be used, and the system may receive input (e.g., from the pilot, from an automatic flight controller) to change the system to a different state or mode for a particular phase of the upcoming flight. Other sensors may include a pitot tube to measure the airspeed of the aircraft, an altimeter to measure the altitude of the aircraft, and / or a global positioning system (GPS) or similar geographic location sensor to determine the position relative to the ground and / or known / mapped structures.

[0071] In various embodiments, controller 905 may also communicate with one or more batteries or battery management systems to monitor their charge levels, control when the batteries are charged or discharged, control when the batteries are used to power generators / motors 925, and control when the batteries are used to directly power other aspects of the aircraft.

[0072] In some embodiments, the controller 905 communicates with devices onboard the aircraft that are hardwired to the controller 905, and / or with wireless transceivers that may be onboard the aircraft or aerospace vehicle to allow the controller 905 to communicate with other computing devices that are not hardwired to the system 900. In this manner, instructions or inputs for implementing the various modes of the flexible architecture described herein may also be received wirelessly from computing devices of remote devices. In other embodiments, the system 900 may communicate only with components onboard the aircraft.

[0073] The controller 905 may also send signals to change the state of the synchromesh transmission 935, for example to engage or disengage a given generator / motor from a respective shaft. The controller 905 may also control the generator / motors 925, 930 and / or the turbine engine 920 such that a desired electrical output from the generator / motors 925, 930 and / or a desired mechanical output to the bypass fan 945 is achieved as described herein.

[0074] The controller 905 may also send signals to monitor and / or control the cooling system 960 or various aspects of the cooling system 960 (such as those shown and described with respect to FIG. 13 herein).

[0075] The following further describes various specific modes that may be implemented using various embodiments of the hybrid powerplant described herein. Figure 10 illustrates a flow chart 1000 illustrating the use of a hybrid powerplant having a turboshaft engine and a planetary gearset engine core in accordance with an exemplary embodiment.

[0076] In a first mode of 1002, maximum or near maximum power output from the turbine engine may be directed to the electric machines to generate electrical power output. Thus, in such a mode, little or no forward thrust may be provided if desired. Such a mode may be beneficial, for example, during vertical takeoff and / or landing maneuvers of a VTOL aircraft. Thus, in 1002, gearing may be controlled with the second electric machine and the turbine engine output to direct power primarily or entirely to the first electric machine to maximize the vertical takeoff power output of the aircraft. To generate electrical power using the first electric machines, the field current of each of the first electric machines may be modified or adjusted so that each of the first electric machines generates electrical power, rather than being free to rotate and pass power to a planetary gear set.

[0077] In the second mode of 1004, some combination of forward thrust and power generation may be desired. For example, such a mode may be used during transition from forward flight to vertical takeoff and / or landing maneuvers (which may be powered by electric power). This mode may also be used when a pilot (e.g., human or autonomous) wishes to sacrifice top speed capability (and thus reduced forward thrust) in order to generate high power for other uses of the aircraft, such as high power accessories. This mode of operation may also be used / desired when it is desirable to minimize airflow through the turbofan core heat engine, even when forward thrust is not desired. In other words, the rotation of the bypass fan allows air to pass through the turbine engine as needed without consuming excessive power, while allowing the electric machine to continue to generate significant power. Thus, in 1004, the gearing is controlled at the second electric machine and the turbine engine to send power to the combination of the bypass fan and the first electric machine during transition of the aircraft or during use of the high power accessories.

[0078] In a third mode at 1006, the power generated by the LP turbine and output by the output shaft of the hybrid power plant is transferred entirely or primarily to the bypass fan to generate only or primarily forward thrust. Maximum thrust may be desired, for example, during aircraft cruise (e.g., between takeoff and landing). Thus, in this mode, the aircraft minimizes other power consumption from the shaft (e.g., by the electric machine) to allow the aircraft to achieve maximum or near maximum speed. In other words, in 1006, the gearing can be controlled at the second machine and turbine engine to direct power primarily or entirely to the bypass fan to maximize forward thrust during aircraft cruise / level flight.

[0079] At 1008, the second mode can be executed again to return the aircraft to the vertical flight mode or during use of the high power accessory. When transitioning the aircraft, this can be to prepare the aircraft to execute the vertical flight mode so that it can perform hovering, landing, etc. At 1010, the first mode is executed again so that the aircraft can perform a vertical landing, hover, or otherwise execute the vertical flight mode.

[0080] A further fourth mode, not shown in FIG. 10, can be used when forward thrust is required from the turbofan's bypass fan without starting or operating the turbofan's core heat engine (such as a turbine engine). This can be achieved by using an on-board energy storage device (e.g., a battery or batteries, etc.) to drive a motor / generator as an electric motor. Such operation can be for short bursts of power to the bypass fan or for additional safety and survivability in case the core heat engine fails. To perform such operation, the output shaft of the electric machine can be directly or indirectly coupled to the shaft of the bypass fan such that the bypass fan is actually driven by the output of the electric machine. For example, as described herein, the shaft of the electric machine can be permanently connected to the turbine engine output shaft such that the bypass fan can be further driven by the electric machine, or the shaft of the electric machine can be connected to the turbine engine shaft via a clutch, transmission, etc., such that the electric machine can be selectively connected to the main turbine output shaft to drive the bypass fan to help generate thrust.

[0081] In this manner, method 1000 allows a VTOL aircraft to perform all phases of desired flight, including vertical takeoff (1002), transition from vertical to horizontal flight (1004), horizontal / cruise flight (1006), transition from horizontal to vertical flight (1008), and vertical landing (1010).

[0082] In various embodiments in which a transmission such as a synchromesh transmission is used, it may be desirable to sense (e.g., using a sensor and / or a controller) the RPM of the turbine shaft and the rotor of the machine (or a shaft connected thereto). In this way, the difference in RPM between the turbine shaft and the rotor of the electric machine can be determined. If the RPM of the turbine output shaft is high (e.g., 29,000 RPM) and the initial RPM of the rotor of the electric machine is low (e.g., close to zero) when not actively driven, the power transmitted by the transmission (e.g., the synchro cone of a synchromesh transmission) and the heat generated within the transmission may be excessive when used to match between such high and low RPMs, leading to premature wear and / or failure. To limit this effect, high voltage energy stored elsewhere in the system may be used to drive a motor / generator in motor mode (e.g., by sending a control signal from a controller to the transmission) before the synchro cone and dog gear arrangement are engaged, increasing the RPM of the rotor to a target value close to the N1 speed of the turbine output shaft. In this manner, RPM matching of the synchro cones may include adjusting the relative rotational speed between the turbine shaft and the electric machine rotor before the dog gears engage, which results in less power being absorbed by the synchro cones as the cones engage, minimizing heat generation and energy loss. Figure 11 is a flow chart 1100 illustrating such use of a transmission device to engage the rotor and shaft of an electric motor / generator, according to an exemplary embodiment.

[0083] At 1102, the RPM of the turbine shaft is measured. At 1104, the RPM of the electric machine rotor is measured. At 1106, the electric machine is controlled to adjust the rotor RPM to a desired RPM, such as at or near the turbine shaft RPM. When the controller determines that the electric machine rotor RPM has reached the desired RPM, it can send a control signal to a transmission to engage the electric machine with the turbine shaft. In various embodiments, a similar method can be implemented for an electric machine connected to a ring gear of a planetary gear set. For example, the RPM of a shaft connected to a gear receiving rotation from the ring gear and the rotor of the electric machine is measured, and the electric machine is controlled to bring the rotor RPM close to or match the shaft from the gear set, thereby allowing the transmission to engage the shaft and rotor of the electric machine. In another alternative embodiment, if the electric machine is already attached to the ring gear using gears as shown in FIG. 3B, the ring gear and the gear connected to the ring gear can be engaged or disengaged to decouple or couple the electric machine from the ring gear.

[0084] FIG. 12 is a schematic diagram illustrating a system having multiple electric motor / generators 1215, 1220, 1225, 1230, according to an exemplary embodiment. The motor / generators 1215, 1220, 1225 are primarily used for power generation (e.g., may be similar to or may be the electric machines 415, 420, 425 of FIGS. 4-6) and may be connected to respective inverters 1235, 1240, 1245 to convert AC power to DC power and output the DC power to a DC bus 1275. The inverters 1235, 1240, 1245 may also function as motor controllers. When the total power generated exceeds about 1 MW, such a system may include multiple inverters, and in a system including multiple motor / generators, multiple inverters may be used for each electric machine as well as for each motor / generator. When these multiple inverters are mounted close to the motor / generators, there may be an advantage in limiting electromagnetic interference. The electric machine may be positioned to block or otherwise displace airflow from the bypass fan, thereby limiting the net thrust generated. In various embodiments, the inverter may be located in the nacelle outside of the bypass fan duct. This may have the advantages of improving overall airflow efficiency, providing an efficient high voltage bus (e.g., DC bus 1275), and providing efficient cooling for the components described herein.

[0085] The electric machine 1230 may be an electric machine connected to a ring gear and may have an inverter 1250 to convert power from DC to AC for use by the electric machine 1230, or to convert power generated by the electric machine 1230 from AC to DC and output to the DC bus 1275. A battery or battery pack / module 1280 (or other type of electrical energy storage device) may also be connected to the DC bus 1275. Aircraft components that consume electricity, such as the vertical flight motor 1260 and / or the high power accessories 1270, may also be connected to the DC bus via their own inverters 1255 and 1265 to provide AC power to those components. In various embodiments, components that use DC power may connect directly to the DC bus without the use of an inverter. In various embodiments, an AC bus may be used instead of or in addition to the DC bus. In such an embodiment, the AC power output by the various electric machines may be supplied to various aspects of the aircraft without conversion to DC power using an inverter. An inverter may then be used with a battery or other DC power source to output the AC power to the AC bus. The various components of Figure 12 may be controlled, sensed, monitored, etc. by a computing device. For example, the processor / controller 905, alone or in combination with other devices, may be used to control, sense, monitor, etc. the various aspects shown in Figure 12.

[0086] FIG. 13 is a schematic diagram illustrating an air cycle for cooling mechanical components of an aircraft according to an exemplary embodiment. In various embodiments herein, electric machines (e.g., electric machines that convert turbine output to electrical power for the aircraft and / or electric machines that help form a power blending function by controlling the rotation of a ring gear or other gear of a planetary gear set) may have electronic losses that manifest in the form of waste heat. Heat buildup around or in other components near the electric machine may reduce and / or damage the performance of the electric machine or other components, and may even lead to failure. Therefore, it may be desirable to remove excess heat from the electric machine and / or surrounding components. Cool air from the air cycle illustrated in FIG. 13 may be directed to the electric machines and / or their inverters to cool the surrounding components, such as the electric machines and their respective inverters. For example, in FIG. 13, hot air from a turbine compressor (e.g., a turbine engine, such as in FIGS. 1, 2A-2D, 3B, 9, etc.) may be input to compressor 1305 of air cooling system 1300. The air may be compressed in compressor 1305 to a higher pressure and temperature and then input to heat exchanger 1310. Ambient air may pass through heat exchanger 1310 and the hot high pressure air from compressor 1305 becomes a high pressure cold air stream that is sent to turbine 1315 of air cooling system 1300. The cooled air may be used to cool any of the components described herein, including any of the components of the mixed turbofan or parallel hybrid turbofan described herein (e.g., electric machines, electric motors, inverters, accessories such as batteries or energy storage systems, high power accessories, etc.). A portion of the cool air expanded in turbine 1315 may also be used to cool the cabin of the aircraft.The compressor 1305 and / or turbine 1315 of Figure 13 may be separate from the compressor and turbine stages of a turbine engine used in a mixed turbofan or parallel hybrid turbofan as described herein, or the compressor 1305 and / or turbine 1315 of Figure 13 may be part of or a stage of a turbine engine used in a mixed turbofan or parallel hybrid turbofan according to various embodiments described herein. As such, components already present in the turbine engine of various embodiments herein may be used in part to cool other components of a mixed turbofan or parallel hybrid turbofan as described herein.

[0087] At least some aspects of the disclosure are described below with reference to the following numbered clauses: 1. An aircraft powerplant, comprising: an engine having a power output shaft; a power transmission device coupled to a power output shaft of the engine, the power transmission device configured to split a power output of the engine into a mechanical power output and an electrical power output, the power transmission device being adjustable such that a majority of the power output from the engine is output as either the mechanical power output or the electrical power output; a propulsion mechanism coupled to a mechanical power output; a control system; The control system includes: Directing a majority of the engine's power output to a propulsion mechanism to generate thrust; or A majority of the engine's power output is configured to be delivered as electrical power output via the electrical power output. 2. The aircraft powerplant of clause 1, wherein the control system is configured such that the power transfer device selectively divides the power output of the engine between an electric power output and a mechanical power output, each of the electric power output and the mechanical power output receiving between 20% and 80% of the total power output of the engine, the total power output of the engine representing 100%. 3. An aircraft powerplant as described in clause 1, wherein the driveline provides at least 90% of the engine's power output to the electrical power output and provides less than 10% of the engine's power output to the propulsion system while the engine is operating at more than 70% capacity. 4. An aircraft powerplant as described in clause 1, wherein the engine includes a turbine engine, a piston engine, or a rotary engine. 5. An aircraft powerplant as described in clause 1, wherein the electrical power generated by the electric machine at a power output is at least 250 kilowatts (kW) at maximum power, at least 370 kW at maximum power, at least 500 kW at maximum power, or at least 1 megawatt (MW) at maximum power. 6. An aircraft powerplant as described in clause 1, wherein the propulsion mechanism includes a bypass fan or a ducted bypass fan. 7. An aircraft powerplant as described in clause 1, wherein the propulsion mechanism includes a propeller. 8. The aircraft powerplant of clause 1, wherein the driveline includes an electric machine configured to generate electrical power based on a power output from the engine allocated to the electric machine. 9. The aircraft powerplant of clause 6, wherein the electric machine is configured to provide power to the power output, and the power is used to drive an electric motor configured to generate thrust for the aircraft. 10. An aircraft powerplant as described in clause 7, wherein the propulsion mechanism is configured to generate forward thrust for the aircraft, the propulsion mechanism is configured to generate forward thrust for a horizontal flight mode of the aircraft, and the electric motor is configured to generate vertical thrust for a vertical flight mode of the aircraft. 11. The power transmission device is At least 95% of the power output from the engine is output as a mechanical power output, while no more than 5% of the power output from the engine is output as an electrical power output; and 2. The aircraft powerplant of claim 1, configured to adjust the split of power output from the engine such that at least 95% of the power output from the engine is output to an electrical power output, while no more than 5% of the power output from the engine is output to a mechanical power output. 12. The power transmission device is At least 98% of the power output from the engine is delivered to a mechanical power output, while no more than 2% of the power output from the engine is delivered to an electrical power output; and 2. The aircraft powerplant of claim 1, configured to adjust the split of power output from the engine such that at least 98% of the power output from the engine is output to an electrical power output, while no more than 2% of the power output from the engine is output to a mechanical power output. 13. An aircraft powerplant as described in clause 1, wherein the engine and driveline are mounted within a nacelle housing of the aircraft. 14. An aircraft powerplant as described in clause 1, wherein the power output is configured to output power at a nominal voltage of 400V, 800V, 1000V, 1200V, 1500V, 2.4kV, or 3kV. 15. The aircraft powerplant of clause 12, wherein the power transmission includes an electric machine, and further wherein the electric machine is configured to output electrical power at a nominal voltage via a voltage conversion device. 16. A power transmission includes a planetary gear set, the planetary gear set comprising: a sun gear coupled to the power output shaft; a planet carrier coupled to an electric machine or a mechanical power output; a ring gear coupled to the electric machine or to the mechanical power output; 2. The aircraft powerplant of claim 1, wherein an output of the electric machine is coupled to an electrical power output. 17. An aircraft powerplant comprising: a turbine engine having a power output shaft; a power transmission coupled to a power output shaft of the turbine engine, the power transmission configured to divide a power output of the engine between a mechanical power output and an electrical power output, the power transmission being adjustable such that a majority of the power output from the turbine engine is output as either the mechanical power output or the electrical power output; a propulsion mechanism coupled to a mechanical power output; a control system; The control system includes: Directing a majority of the turbine engine's power output to a propulsion mechanism to generate thrust; or A majority of the power output of the turbine engine is configured to be delivered as electrical power output via the electrical power output. 18. The aircraft powerplant of clause 17, wherein the control system is configured to cause the power transmission to selectively divide a power output of the turbine engine between a mechanical power output and an electric power output, whereby each of the electric power output and the mechanical power output receives between 20% and 80% of the total power output of the turbine engine, the total power output of the turbine engine representing 100%. 19. An aircraft powerplant as described in clause 17, wherein the driveline delivers at least 90% of the turbine engine's power output to the electrical power output and delivers less than 10% of the turbine engine's power output to the propulsion mechanism while the turbine engine is operating at greater than 70% capacity. 20. An aircraft powerplant as described in clause 16, wherein the driveline provides substantially all of the power output from the turbine engine to the electric machine during a vertical flight mode of the aircraft. 21. An aircraft powerplant as described in clause 17, wherein the power transmission outputs substantially all of the power output from the turbine engine to the propulsion mechanism during a vertical flight mode of the aircraft. 22. A method of dividing power output from an aircraft engine between an electric power output and a mechanical power output, comprising: controlling a driveline of the aircraft in a first mode of operation to generate electrical power using substantially all of the power output from the engine; and in a second mode of operation, controlling the driveline to generate little or no electricity from mechanical power output from the engine; The second mode of operation further includes controlling the driveline such that most or all of the power output from the engine is directed to a mechanical power output. 23. A power transmission device includes a gear set, the gear set comprising: a sun gear connected to an output shaft of the engine; a plurality of planetary gears connected to a planetary carrier, the planetary carrier being connected to a propulsion mechanism; and 19. The method of claim 18, comprising: 24. The method of claim 18, wherein the driveline includes an electric machine, and further wherein in a first operating mode, a first field current is applied to a stator of the electric machine, and in a second operating mode, a second field current different from the first field current is applied to the stator. 25. An aircraft power plant, comprising: an engine including a power output shaft configured to output power from the engine; Bypass fan, Electrical machinery and a transmission device, the transmission includes an input, a first output shaft, and a second output shaft; a power output shaft from the engine configured to drive an input of the transmission; The first output shaft is coupled to the bypass fan. The second output shaft is coupled to the electric machine. The transmission is controllable to vary the proportion of power from the engine between the first output shaft and the second output shaft, thereby selectively providing a majority of the power to either the first output shaft or the second output shaft. 26. The aircraft powerplant of clause 25, wherein the electric machine includes a plurality of electric machines, and further wherein the second output shaft includes a plurality of second output shafts. 27. The electric machine is a first electric machine, the transmission includes a planetary gear set, and the planetary gear set is a sun gear coupled to the power output shaft; a planet carrier coupled to a second electric machine or a bypass fan; and a ring gear coupled to the second electric machine or the bypass fan. 28. An aircraft powerplant as described in clause 25, wherein the transmission device is controllable to selectively direct substantially all of the engine torque provided to the input to either the first output shaft or the second output shaft. 29. An aircraft powerplant comprising: an engine including a shaft configured to output power from the engine; Bypass fan, A first electric machine; A second electric machine; and a gear set; The gear set is Sun gear and A plurality of planetary gears connected to a planetary carrier; a ring gear; the shaft is configured to drive an input of the first electric machine; The shaft is further configured to drive a sun gear; The second electric machine is configured to drive the ring gear; The bypass fan is connected to the planet carrier. 30. The aircraft powerplant of clause 29, wherein the first electric machine is configured to output electrical power generated based on rotation of the shaft. 31. An aircraft powerplant as defined in clause 29, including a turbine engine, a piston engine or a rotary engine. 32. The aircraft powerplant of clause 29, wherein the second electric machine is controllable to rotate the ring gear at revolutions per minute (RPM) and not rotate the planet carrier while the first electric machine drives the sun gear. 33. An aircraft powerplant as described in clause 32, wherein the bypass fan does not rotate while the planet carrier is not rotating. 34. An aircraft powerplant as described in clause 32, wherein the rotating part of the first electric machine is driven by a shaft of the engine while the planet carrier is not rotating. 35. The aircraft powerplant of clause 32, wherein the RPM is a first RPM, and further wherein the second electric machine is controllable to rotate the ring gear at a second RPM and rotate the planet carrier while the first electric machine drives the sun gear. 36. An aircraft powerplant as described in clause 35, wherein while the planet carrier rotates, the bypass fan also rotates to provide thrust to the aircraft. 37. The aircraft powerplant of clause 35, wherein the second electric machine is generating electrical power while the second electric machine is controllable to rotate the ring gear at the second RPM. 38. The aircraft powerplant of clause 35, wherein the first electric machine is configured to generate electrical power based on an input of the first electric machine driven by the shaft. 39. An aircraft powerplant as described in clause 38, wherein a rotating component of the first electric machine is driven by a shaft, but no magnetic field current is applied to a stator of the first electric machine, and the first electric machine does not generate electrical power while the rotating component is rotating. 40. The aircraft powerplant of clause 38, wherein an input of the first electric machine is configured to be selectively disengaged from a shaft of the engine, and wherein the first electric machine does not generate electrical power while the input of the first electric machine is disengaged from the shaft of the engine. 41. The aircraft powerplant of clause 40, further comprising a synchromesh transmission configured to selectively disengage the input of the first electric machine from the shaft of the engine. 42. The aircraft powerplant of clause 40, further including a transmission or clutch having a first side connected to an input of the first electric machine and a second side connected to a rotating part of the first electric machine, and further wherein the first electric machine is controllable to cause a first revolutions per minute (RPM) of the second side of the transmission to match a second RPM of the first side of the transmission prior to engagement of the first and second sides. 43. The aircraft powerplant of clause 35, wherein the first electric machine is configured to output power to the bus. 44. The aircraft powerplant of clause 43, wherein the second electric machine is configured to be driven by power from the bus or configured to function as a generator to supply power to the bus. 45. An aircraft powerplant as described in clause 44, wherein the bus is further connected to an energy storage device. 46. ​​An aircraft powerplant as described in clause 45, further including a gear for reducing RPM between the engine shaft and the input of the first electric machine. 47. The aircraft powerplant of clause 45, further including a third electric machine, the shaft being further configured to drive the third electric machine. 48. The aircraft powerplant of clause 47, wherein the shaft includes a first gear, the input of the first electric machine includes a second gear configured to rotate with the first gear, and the input of the third electric machine includes a third gear configured to rotate with the first gear. 49. The aircraft powerplant of clause 47, wherein each of the first electric machine, the second electric machine, and the third electric machine are disposed at different positions about the axis of the shaft. 50. A method of dividing power output from an engine between a first electric machine and a bypass fan, the method comprising: The method further includes controlling a first electric machine to generate electricity using most or all of the mechanical power output from the engine in a first mode of operation, and controlling a gear set using a second electric machine to direct most or all of the mechanical power output from the engine away from the bypass fan in the first mode of operation, the gear set comprising: a sun gear connected to an output shaft of the engine; a plurality of planetary gears connected to a planetary carrier, the planetary carrier being connected to a bypass fan; a ring gear connected to the second electric machine; controlling, in a second mode of operation using the first electric machine and the second electric machine, the first electric machine to generate electricity using a first substantial portion of the mechanical power output from the engine and to output a second substantial portion of the mechanical power output from the engine to the bypass fan; and in a third mode of operation, controlling the first electric machine to generate little or no electricity from mechanical power output from the engine; The third mode of operation further includes controlling the gear set using the second electric machine such that most or all of the mechanical power output from the engine is directed to the bypass fan. 51. The method according to clause 50, wherein during the first mode of operation, the aircraft implementing the method is in a vertical flight mode. 52. The method of claim 50, wherein during the second mode of operation, the aircraft implementing the method is performing a transition between a vertical flight mode and a horizontal flight mode. 53. The method of clause 50, wherein during the second mode of operation, the aircraft in which the method is implemented is in a level flight mode and the high power accessory is also used. 54. The method according to clause 50, wherein during the third mode of operation, the aircraft implementing the method is in a level flight mode. 55. The method of clause 50, further comprising controlling a revolutions per minute (RPM) of the first electric machine to match an RPM of a disengagement input to the first electric machine, the disengagement input being driven by a powered output shaft of the engine. 56. The method of clause 55, further comprising the step of: matching an RPM of the first electric machine with an RPM of a disengagement input to the first electric machine, followed by engaging a rotating part of the first electric machine with the input to the first electric machine. 57. The method of claim 56, wherein the rotating parts of the first electric machine are engaged with the input to the first electric machine via a synchromesh transmission device configured to connect the input to the first electric machine and the rotating parts of the first electric machine. 58. A power transmission system for an aircraft, comprising: a shaft input configured to receive rotational power from an engine of the aircraft; a shaft output configured to output mechanical power to a propulsion mechanism of the aircraft; an electrical output configured to output electrical power; an electric machine configured to receive rotational power via a shaft input and selectively generate an electrical power output via an electrical output; The electrical power selectively generated by the electric machine is at least a majority of the rotational power received from the aircraft engine via the shaft input. 59. The power transmission device of clause 58, wherein the rotor of the electric machine is coupled to the shaft input. 60. The power transmission device of clause 58, wherein the electric machine is configured to generate a power output based on a field current applied to a stator of the electric machine. 61. The power transmission device of clause 58, wherein the shaft input includes splines that correspond to a gear attached to a rotor of the electric machine, whereby the rotor of the electric machine rotates along the splines of the shaft input. 62. The power transmission device of clause 58, wherein the electric machine includes two or more electric machines, each electric machine having a rotor configured to rotate along a shaft input. 63. A power transmission device as described in clause 62, wherein each of the two or more electric machines has a respective gear attached to a respective rotor and configured to rotate along the splines of the shaft input. 64. The power transmission device of clause 58, further including a planetary gear set connected to the shaft input and to the propulsion mechanism, the planetary gear set configured to selectively output mechanical power to the propulsion mechanism. 65. The power transmission apparatus of clause 64, wherein the electric machine is a first electric machine and further includes a second electric machine having an output connected to a component of the planetary gear set, the second electric machine configured to selectively control whether the planetary gear set outputs mechanical power to the propulsion mechanism. 66. The power transmission device of clause 65, wherein the first electric machine and the second electric machine are disposed on opposite sides of the input shaft. 67. The power transmission apparatus of clause 58, further comprising a synchromesh transmission apparatus configured for selective engagement with a rotor of the electric machine. 68. The power transmission device of clause 67, wherein the electric machine includes an inrunner arrangement in which the input shaft passes through a rotor and a stator of the electric machine. 69. A driveline arrangement as described in clause 58, wherein the electric machine is located at any point along the shaft input driven by the engine. 70. A power transmission device as described in clause 58, wherein a first axis passing through a centre of the rotor of the electric machine is parallel to a second axis of the shaft input. 71. A power transmission device as described in clause 58, wherein a first axis passing through a centre of the rotor of the electric machine is not parallel to a second axis of the shaft input, and further wherein a bevel gear is used to connect a gear of the electric machine to the shaft input. 72. A driveline arrangement as described in clause 58, wherein the electric machine is positioned forward of the engine and aft of the shaft output of the aircraft, whereby the electric machine is between the engine and the shaft output. 73. A driveline arrangement as described in clause 58, wherein the electric machine is located forward of both the engine and the shaft output of the aircraft. 74. A driveline arrangement as described in clause 58, wherein the electric machine is located aft of both the aircraft engine and the shaft output. 75. A power transmission system for an aircraft, comprising: a shaft input configured to receive rotational power from a turbine engine of the aircraft; a shaft output configured to output mechanical power to a propulsion mechanism of the aircraft; an electrical output configured to output power to an electric motor of the aircraft; Electrical machinery and a control system configured to selectively cause the electric machine to generate electrical power and to output electrical power from the electrical output to the electric motor; the electrical power selectively generated by the electric machine is at least a majority of the rotational power received from the aircraft engine via the shaft input; The control system is further selectively configured such that an amount of electrical power generated by the electric machine is less than a majority of the rotational power received from the engine while outputting mechanical power to a propulsion system of the aircraft. 76. The driveline of clause 75, wherein the electric machine includes at least three electric machines, each electric machine configured to generate electrical power. 77. The driveline of clause 76, wherein the control system selectively controls the field current of each of the at least three electric machines such that only a subset of the at least three electric machines produces electrical power at a given time. 78. A method of dividing power output from an aircraft engine between an electric machine and a bypass fan, comprising: receiving rotational power from an engine via an input shaft of a power transmission; and selectively splitting the electrical power output from the driveline between a mechanical power output connected to the propulsion mechanism and an electrical output of the driveline using gearing, clutches, and / or transmission components of the driveline; an amount of power output at the electrical output is selectable to be a majority of the power input from the engine at the input shaft; The electrical power output at the electrical output is generated by at least one electric machine of the driveline. 79. The method of claim 78, wherein while the aircraft is in vertical flight mode, the amount of power output at the electrical output is a majority of the power input from the engine. 80. The method of claim 79, further comprising: while the aircraft is in a level flight mode, an amount of mechanical power output to the propulsion mechanism is a majority of the power input from the engine at the input shaft. 81. A power transmission system for an aircraft, comprising: a power input shaft configured to receive power from an engine of the aircraft; A propulsion mechanism; Electrical machinery and a power output shaft configured to output mechanical power to a propulsion mechanism; an electrical output configured to output the electrical power generated by the electric machine; the driveline is controllable to vary a proportion of power from the engine between electrical power output at the electric machine and mechanical power output at the power output shaft; The driveline is controllable so that a majority of the power is selectively delivered to either the power output shaft or the electric machine. 82. The power transmission arrangement of clause 81, wherein the electric machine is a first electric machine, and the power transmission arrangement further includes a second electric machine and a gear set configured to split the power output between the power output shaft and the electric machines. 83. The power transmission device according to clause 82, wherein the gear set is a planetary gear set including a sun gear, a plurality of planetary gears connected to a planet carrier, and a ring gear. 84. A power transmission device as described in clause 83, wherein the power output shaft is connected to the sun gear and the propulsion mechanism is connected to the planet carrier. 85. The power transmission device of clause 84, wherein the second electric machine is controllable to rotate the ring gear at a revolutions per minute (RPM) at which the planet carrier and therefore the propulsion mechanism do not rotate. 86. A power transmission device as described in clause 85, wherein the rotating part of the first electric machine is driven by the power input shaft while the planet carrier is not rotating. 87. A power transmission device as described in clause 85, wherein the propulsion mechanism rotates while the planet carrier rotates. 88. The driveline of claim 84, wherein the second electric machine is controllable to rotate the ring gear at a revolutions per minute (RPM) at which the planet carrier rotates and thus the propulsion mechanism rotates. 89. The power transmission device of clause 88, wherein the second electric machine can be disengaged from the ring gear using a clutch or a synchromesh gear. 90. The power transmission device of clause 88, wherein less than a majority of the power from the engine is output as electrical power via the electrical output while the propulsion mechanism is rotating. 91. A gear set configured to divide the power output between the power output shaft and an electric machine; and a controllable electromechanical pin, lock, band clutch, brake, or other type of locking mechanism configured to lock the gear set components in position. 92. A power transmission device as described in clause 91, wherein while the component of the gear set is locked, the gear set is configured to rotate the propulsion mechanism to provide propulsive force, and while the component of the gear set is unlocked, the component is configured to rotate and not rotate the propulsion mechanism. 93. The power transmission device of clause 81 further including gearing for adjusting revolutions per minute (RPM) between any of the power input shaft, the power output shaft, the propulsion mechanism, and / or the rotating mechanism of the electric machine. 94. A power transmission device as described in clause 93, wherein the RPM of the rotating mechanism is different from the RPM of the power input shaft. 95. The power transmission device of clause 81, further comprising a synchromesh gear configured to engage and disengage the electric machine from the power input shaft. 96. The power transmission device of clause 81, wherein the field current of the electric machine is configured to be selectively controlled such that the electric machine produces little or no power while a majority of the power from the engine is output to the power output shaft. 97. A method of dividing power output from an engine between a first electric machine and a propulsion mechanism, the method comprising: controlling a first electric machine to generate electricity using most or all of the mechanical power output from the engine in a first mode of operation, the first mode of operation including controlling a gear set using a second electric machine such that most or all of the mechanical power output from the engine is not directed to a propulsion mechanism; in a second mode of operation using the first electric machine and the second electric machine, controlling the first electric machine to generate electricity using a first substantial portion of the mechanical power output from the engine and to output a second substantial portion of the mechanical power output from the engine to a propulsion mechanism; and in a third mode of operation, controlling the first electric machine to generate little or no electricity from mechanical power output from the engine; The third mode of operation further includes controlling the gear set using the second electric machine such that most or all of the mechanical power output from the engine is directed to the propulsion mechanism. 98. The method of clause 97, wherein the first electric machine is controlled based on a field current applied to the first electric machine, gearing between a shaft of the engine and a rotor of the first electric machine, or a clutch between a shaft of the engine and a rotor of the first electric machine. 99. A method of dividing power output from an engine between an electric machine and a propulsion mechanism, the method comprising: controlling the electric machine in a first mode of operation to generate electricity using most or all of the mechanical power output from the engine, the first mode of operation further including controlling a gear set and / or clutch such that most or all of the mechanical power output from the engine is not directed to a propulsion mechanism; Controlling the electric machine in a second mode of operation to generate little or no electricity from the mechanical power output from the engine, the second mode of operation further including controlling the gear set and / or clutch such that most or all of the mechanical power output from the engine is directed to the propulsion mechanism. 100. The method of clause 99, wherein the gear set and / or clutch includes at least a first synchromesh gear or a first clutch configured to engage or disengage a rotor of the electric machine and a power shaft connected to the engine, and the gear set and / or clutch further includes at least a second synchromesh gear or a second clutch configured to engage or disengage a rotor of the electric machine and a power shaft connected to the engine.

[0088] It will be understood that various physical components are described herein as being connected or coupled to one another. The term connected or coupled as used herein may refer to direct or indirect coupling or connection. For example, as described herein, certain components may be directly coupled or connected to one another when there is no intermediate component connected to the connection between the two components. In various embodiments and examples described herein, components may also be indirectly coupled or connected to one another via gears, clutches, couplings, transmissions, etc. Thus, when components are generally described as being connected or coupled to one another, such coupling or connection may be indirect or direct. Components may be specifically described herein as being directly connected or coupled, as well as being indirectly connected or coupled.

[0089] 17 is a schematic diagram of an example computing environment including a general-purpose computing system environment 100, such as a desktop computer, laptop, smartphone, tablet, or other device that includes the capability to execute instructions, such as those stored in a non-transitory computer-readable medium. Various computing devices disclosed herein (e.g., processor / controller 905, memory 910, or other computing devices in communication with other components of the aircraft or controllers that may be part of the aircraft's control system, whether onboard the aircraft or remote from the aircraft) may be similar to computing system 100 or may include some components of computing system 100. Additionally, while described and illustrated in the context of a single computing system 100, one skilled in the art will appreciate that various tasks described below may be performed in a distributed environment including multiple computing systems 100 linked via a local or wide area network. In this distributed environment, executable instructions may be associated with and / or executed by one or more of the multiple computing systems 100.

[0090] In its most basic configuration, the computing system environment 100 typically includes at least one processing unit 102 and at least one memory 104, which may be linked via a bus 106. Depending on the exact configuration and type of computing system environment, the memory 104 may be volatile (such as RAM 110), non-volatile (such as ROM 108, flash memory, etc.), or a combination of the two. The computing system environment 100 may have additional features and / or functionality. For example, the computing system environment 100 may also include additional storage (erasable and non-erasable), including, but not limited to, magnetic or optical disks, tape drives, flash drives, and the like. Such additional memory devices may be accessible to the computing system environment 100, for example, via a hard disk drive interface 112, a magnetic disk drive interface 114, and / or an optical disk drive interface 116. As will be appreciated, each of these devices linked to the system bus 306 allows for reading and writing from the hard disk 118, the erasable magnetic disk 120, and / or the erasable optical disk 122, such as a CD / DVD ROM or other optical medium. The drive interfaces and their associated computer readable media allow for non-volatile storage of computer readable instructions, data structures, program modules, and other data for the computing system environment 100. Those skilled in the art will appreciate that other types of computer readable media capable of storing data may also be used for this same purpose. Examples of such media devices include, but are not limited to, magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, random access memory, nano drives, memory sticks, other read / write memory and / or read-only memory, and / or other methods or technologies for storing information, such as computer readable instructions, data structures, program modules, other data, and the like.Any such computer storage media may be part of the computing system environment 100.

[0091] A number of program modules may be stored in one or more memory / media devices. For example, a basic input / output system (BIOS) 124, containing the basic routines that help to transfer information between elements within the computing system environment 100, such as during start-up, may be stored in ROM 108. Similarly, RAM 110, hard drive 118, and / or peripheral memory devices may be used to store computer-executable instructions including an operating system 126, one or more application programs 128 (which may include functionality disclosed herein, for example), other program modules 130, and / or program data 122. Additionally, computer-executable instructions may be downloaded into the computing environment 100, as needed, for example via a network connection.

[0092] An end user may enter commands and information into the computing system environment 100 through input devices such as a keyboard 134 and / or a pointing device 136. Although not shown, other input devices may include a microphone, joystick, game pad, scanner, etc. These and other input devices are typically connected to the processing unit 102 through a peripherals interface 138, which is connected to the bus 106. The input devices may be connected directly or indirectly to the processor 102 through an interface such as a parallel port, game port, Firewire, or universal serial bus (USB). To display information from the computing system environment 100, a monitor 140 or other type of display device may also be connected to the bus 106 through an interface such as a video adapter 132. In addition to the monitor 140, the computing system environment 100 may also include other peripheral output devices (not shown), such as speakers and printers.

[0093] The computing system environment 100 may also utilize logical connections to one or more computing system environments. Communications between the computing system environment 100 and a remote computing system environment may be exchanged through another processing device, such as a network router 152 responsible for network routing. Communications with the network router 152 may be performed through a network interface component 154. Thus, it is understood that within such a network environment, such as the Internet, the World Wide Web, a LAN, or other similar types of wired or wireless networks, program modules depicted relative to the computing system environment 100, or portions thereof, may be stored in a memory storage device of the computing system environment 100.

[0094] The computing system environment 100 may also include location determination hardware 186 for determining the location of the computing system environment 100. In some cases, the location determination hardware 156 may include, for example, a GPS antenna, an RFID chip or reader, a WiFi antenna, or other computing hardware that can be used to capture or transmit signals that can be used to determine the location of the computing system environment 100.

[0095] Although specific embodiments have been described in this disclosure, it is understood that the claims are not intended to be limited to these embodiments unless expressly set forth in the claims. Rather, the disclosure is intended to cover alternatives, modifications, and equivalents that may fall within the spirit and scope of the disclosure. Furthermore, in the detailed description of the disclosure, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be apparent to those skilled in the art that systems and methods consistent with the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure various aspects of the present disclosure.

[0096] Some of the detailed descriptions of this disclosure are presented in terms of procedures, logic blocks, processes, and other symbolic representations of operations on data bits within a computer or digital system memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, logic block, process, or the like, is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical operations of physical quantities. Usually, though not necessarily, these physical operations take the form of electrical or magnetic data capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system or similar electronic computing device. For convenience, and with reference to common usage, such data will be referred to as bits, values, elements, symbols, characters, terms, numbers, or the like with reference to the various embodiments presently disclosed.

[0097] However, it should be noted that these terms should be interpreted as referring to physical operations and quantities, are merely convenient labels, and should be further interpreted in light of the terms commonly used in the art. Unless otherwise indicated, as will be apparent from the discussion herein, throughout the discussion of the present embodiments, discussions using terms such as "determine" or "output" or "transmit" or "record" or "locate" or "store" or "display" or "receive" or "recognize" or "use" or "generate" or "provide" or "access" or "confirm" or "notify" or "deliver" are understood to refer to the operations and processes of a computer system or similar electronic computing device that manipulates and transforms data. Data is represented as physical quantities (electronic quantities) in the registers and memory of the computer system, and is converted to other data that are also represented as physical quantities in the memory or registers of the computer system, or in other information storage, transmission, or display devices as described herein or understood by those skilled in the art.

[0098] In an exemplary embodiment, any of the operations described herein may be implemented, at least in part, as computer readable instructions stored on a computer readable medium or in a memory that, when executed by a processor, causes a computing device to perform an operation.

[0099] The foregoing description of exemplary embodiments has been presented for purposes of illustration and description, by way of example, and is not intended to be exhaustive or to be limited to the precise form disclosed, and modifications and variations may be possible in light of the above teachings or from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims

1. An aircraft power plant, said aircraft power plant is An engine having a power output shaft, A power transmission device coupled to the power output shaft of the engine, wherein the power transmission device is configured to divide the power output of the engine between mechanical power output and electrical output, and is adjustable so that the majority of the power output from the engine is output to either the mechanical power output or the electrical output, A propulsion mechanism coupled to the aforementioned mechanical power output, Includes a control system, The control system is configured in the power transmission device, The majority of the power output of the engine is sent to the propulsion mechanism to generate thrust, or The engine is configured to send most of its power output as power output via the power output, Aircraft power plant.

2. The aircraft power plant according to claim 1, wherein the control system is configured such that the power transmission device selectively divides the power output of the engine between the power output and the mechanical power output, and each of the power output and the mechanical power output receives 20% to 80% of the total power output of the engine, and the total power output of the engine represents 100%.

3. The aircraft power plant according to claim 1, wherein while the engine is operating at more than 70% of its capacity, the power transmission device supplies at least 90% of the engine's power output to the power output and less than 10% of the engine's power output to the propulsion mechanism.

4. The aircraft power plant according to claim 1, wherein the engine includes a turbine engine, a piston engine, or a rotary engine.

5. The aircraft power plant according to claim 1, wherein the power generated by the electrical machine at the power output is at least 250 kilowatts (kW) at maximum power, at least 370 kW at maximum power, at least 500 kW at maximum power, or at least 1 megawatt (MW) at maximum power.

6. The propulsion mechanism includes a bypass fan, a ducted bypass fan, or a propeller, according to claim 1, for the aircraft power plant.

7. The aircraft power plant according to claim 1, wherein the power transmission device includes an electromachine configured to generate electricity based on the power output from the engine assigned to the electromachine.

8. The aircraft power plant according to claim 7, wherein the electric machine is configured to supply power to the power output, and the power is used to drive an electric motor configured to generate thrust for an aircraft.

9. The aircraft power plant according to claim 8, wherein the propulsion mechanism is configured to generate forward thrust for the aircraft, the propulsion mechanism is configured to generate forward thrust for the aircraft's horizontal flight mode, and the electric motor is configured to generate vertical thrust for the aircraft's vertical flight mode.

10. The power transmission device is At least 95% or at least 98% of the power output from the engine is output to the mechanical power output, while 5% or less or 2% or less of the power output from the engine is output to the electrical power output. The aircraft power plant according to claim 1, configured to adjust the division of the power output from the engine such that at least 95% or at least 98% of the power output from the engine is output to the electrical output, while 5% or less or 2% or less of the power output from the engine is output to the mechanical power output.

11. The aircraft power plant according to claim 1, wherein the engine and the power transmission device are mounted within the nacelle housing of the aircraft.

12. The aforementioned power output is configured to output power at a nominal voltage of 400V, 800V, 1000V, 1200V, 1500V, 2.4kV, or 3kV. The aircraft power plant according to claim 1, wherein the power transmission device includes an electric machine, and the electric machine is configured to output power at a nominal voltage by a voltage converter.

13. The power transmission device includes a planetary gear set, and the planetary gear set is The solar gear connected to the aforementioned power output shaft, A planetary carrier coupled to an electromechanical device or the mechanical power output, Includes the aforementioned electric machine or a ring gear coupled to the aforementioned mechanical power output, The aircraft power plant according to claim 1, wherein the output of the electrical machine is coupled to the power output.

14. A method for dividing the power output from an aircraft engine into electrical output and mechanical power output, the method being: In a first operating mode, the steps include controlling the aircraft's power transmission system to generate electricity using substantially all of the power output from the engine, A second operating mode includes the step of controlling the power transmission device so that little or no power is generated from the mechanical power output from the engine, The second operating mode further includes the step of controlling the power transmission device such that most or all of the power output from the engine is directed to the mechanical power output. method.

15. The power transmission device includes a gear set, and the gear set is A sun gear connected to the output shaft of the aforementioned engine, Multiple planetary gears connected to a planetary carrier, wherein the planetary carrier is connected to a propulsion mechanism, and the planetary gears are connected to the planetary carrier. The method according to claim 14, comprising a ring gear.

16. The power transmission device includes an electric machine, and further, in the first operating mode, a first field current is applied to the stator of the electric machine, and in the second operating mode, a second field current different from the first field current is applied to the stator, according to claim 14.

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