System and method for managing icing on aircraft during flight

Abstract

Embodiments of the present disclosure provide systems and methods for avoiding, removing, or otherwise managing icing that may occur during aircraft flight. Exemplary systems and methods selectively modulate propeller parameters in a manner that does not interfere with the flight path, direct oil from lubrication and cooling paths to target areas of ice-prone surfaces, manage icing in a manner that does not excessively increase the total volume of oil, require larger pumps, or complicate the system, or generate heat in a target area of ​​the propeller assembly by an electric heating system that utilizes propeller motion.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of priority of U.S. Provisional Application No. 63 / 587,117, filed on September 30, 2023, entitled "Systems and Methods for Managing eVTOL Flight in Icing", the content of which is hereby incorporated by reference in its entirety for all purposes.

[0002] The present disclosure generally relates to the field of powered aircraft. More specifically, without limitation, the present disclosure relates to technological innovations in tilt - rotor aircraft using electric propulsion systems. Certain aspects of the present disclosure generally relate to systems and methods for preventing or mitigating icing in electric aircraft. Other aspects of the present disclosure generally relate to improvements in ice prevention or mitigation that can be used in other types of vehicles but provide particular advantages in aerial vehicles.

Background Art

[0003] An electric vertical take - off and landing (eVTOL) aircraft typically includes one or more electric propulsion units (EPUs), each including at least one (fully or partially) electric or hybrid - electric motor and at least one propeller. The propeller includes a plurality of propeller blades (sometimes formed or integrated as a single piece) that rotate around the propeller hub when mechanically driven by a propeller shaft. Each EPU generates thrust by its motor(s) and converts electrical power into mechanical shaft power to rotate the propeller blades.

Summary of the Invention

[0004] Embodiments of the present disclosure provide systems and methods for preventing or alleviating (collectively "managing") icing during flight of any aircraft.

[0005] Some embodiments of the present disclosure provide a method for managing icing on an aircraft, the method comprising determining the icing conditions of the aircraft and performing propeller modulation based on the icing conditions, wherein the propeller modulation includes inducing a first ice management cycle in a first set of one or more propellers of the aircraft and inducing a second ice management cycle in a second set of one or more propellers of the aircraft, the method wherein the first set of one or more propellers is different from the second set of one or more propellers, and the first ice management cycle occurs at a first time interval different from the second time interval of the second ice management cycle.

[0006] Some embodiments of the present disclosure provide a propeller assembly for an aircraft, the propeller assembly comprising: a propeller; a motor assembly coupled to the propeller; a heat exchanger; an oil passage configured to thermally couple the heat exchanger to the motor assembly, comprising a first segment, a second segment, and a third segment; and a nacelle mechanically coupled to the motor assembly, the nacelle comprising an air inlet configured to direct air to the heat exchanger, the air inlet comprising a lower lip relative to a forward flight configuration and an upper lip opposite to the lower lip, the lower lip being further from the motor assembly than the upper lip, the first segment passing through the motor assembly, the second segment passing through the heat exchanger, the third segment passing along the lower lip, and the oil passage bypassing the upper lip.

[0007] Some embodiments of the present disclosure provide a propeller assembly for an aircraft, the propeller assembly comprising: a propeller, which includes a hub and a plurality of propeller blades, each of which has a blade channel inside the propeller blade and is configured to circulate fluid; a motor assembly configured to rotate the propeller around a rotation axis; and an oil passage configured to thermally couple the motor assembly to the plurality of propeller blades by circulating oil through the motor assembly and through the blade channels of each of the plurality of propeller blades, wherein the propeller assembly is configured to transfer heat from the motor assembly to the external environment outside the propeller assembly by heat conduction through the propeller blades.

[0008] Some embodiments of the present disclosure provide a propeller assembly for an aircraft, the propeller assembly comprising: a propeller, the propeller comprising: a hub and a plurality of propeller blades, each of the plurality of propeller blades having a blade channel inside the propeller blade and configured to circulate fluid; a motor assembly configured to rotate the propeller around a rotation axis; and an oil passage configured to circulate oil through the motor assembly and through the blade channels of the plurality of propeller blades to thermally couple the motor assembly to the plurality of propeller blades, wherein the plurality of propeller blades constitute the sole heat exchanger of the motor assembly.

[0009] Some embodiments of the present disclosure provide a propeller assembly for an aircraft, the propeller assembly comprising: a propeller hub; propeller blades coupled to the propeller hub; a spinner coupled to the propeller hub; a spinner rod coupled to the propeller hub; a conductive part; a motor configured to rotate the propeller hub, propeller blades, spinner, spinner rod, and conductive part; and a magnet suspended from the spinner rod and rotationally disconnected from the spinner rod by a bearing, wherein the magnet is configured to generate an electric current in the conductive part when the propeller rotates to manage ice formation on the surface of the propeller assembly.

[0010] Some embodiments of the present disclosure provide a propeller assembly for an aircraft, the propeller assembly comprising: a rotating part, the rotating part including a propeller hub, propeller blades coupled to the propeller hub, a spinner coupled to the propeller hub, and a conductive part; a motor configured to rotate the rotating part; and a magnet configured to remain stationary relative to the motor, the magnet being configured to generate an electric current in the conductive part as the rotating part rotates to manage ice formation on the surface of the rotating part. [Brief explanation of the drawing]

[0011] [Figure 1A] An exemplary VTOL aircraft in a cruising configuration consistent with embodiments of the present disclosure is illustrated.

[0012] [Figure 1B] An exemplary VTOL aircraft in an ascent configuration consistent with embodiments of this disclosure is illustrated.

[0013] [Figure 2] An exemplary ice management system for a distributed propulsion electric aircraft, consistent with embodiments of the present disclosure, is illustrated.

[0014] [Figure 3A]Illustrates an exemplary ice management system for a distributed propulsion electric aircraft consistent with embodiments of the present disclosure.

[0015] [Figure 3B] Illustrates an exemplary ice management method for a distributed propulsion electric aircraft consistent with embodiments of the present disclosure.

[0016] [Figure 4A] Illustrates an exemplary ice management cycle consistent with embodiments of the present disclosure. [Figure 4B] Illustrates an exemplary ice management cycle consistent with embodiments of the present disclosure. [Figure 4C] Illustrates an exemplary ice management cycle consistent with embodiments of the present disclosure.

[0017] [Figure 5] Illustrates an exemplary system for managing asymmetric icing consistent with embodiments of the present disclosure.

[0018] [Figure 6] Illustrates an exemplary system for managing asymmetric icing consistent with embodiments of the present disclosure.

[0019] [Figure 7A] Illustrates an exemplary ice management cycle consistent with embodiments of the present disclosure. [Figure 7B] Illustrates an exemplary ice management cycle consistent with embodiments of the present disclosure. [Figure 7C] Illustrates an exemplary ice management cycle consistent with embodiments of the present disclosure.

[0020] [Figure 8A] Illustrates an exemplary system for managing icing on the surface of an electric aircraft consistent with embodiments of the present disclosure. [Figure 8B] Illustrates an exemplary system for managing icing on the surface of an electric aircraft consistent with embodiments of the present disclosure. [Figure 8C]An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated.

[0021] [Figure 9A] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 9B] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 9C] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 9D] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 9E] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 9F] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 9G] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 9H] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated.

[0022] [Figure 10A] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated. [Figure 10B] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated.

[0023] [Figure 11] An exemplary system for managing icing on the surface of an electric aircraft, consistent with embodiments of this disclosure, is illustrated.

[0024] [Figure 12] An exemplary system for determining the icing conditions on the propeller of an electric aircraft, consistent with embodiments of this disclosure, is illustrated.

[0025] [Figure 13] An exemplary system for determining the icing conditions on the propeller of an electric aircraft, consistent with embodiments of this disclosure, is illustrated.

[0026] [Figure 14] An exemplary system for determining the icing conditions on the propeller of an electric aircraft, consistent with embodiments of this disclosure, is illustrated.

[0027] [Figure 15] An exemplary system for managing ice formation on a spinner, consistent with embodiments of the present disclosure, is illustrated.

[0028] [Figure 16] An exemplary system for managing ice formation on a spinner, consistent with embodiments of the present disclosure, is illustrated.

[0029] [Figure 17A] An exemplary system for managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 17B] An exemplary system for managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated.

[0030] [Figure 18A] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18B] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18C]An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18D] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18E] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18F] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18G] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18H] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18I] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18J] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Figure 18K] An exemplary system for electrically managing icing on a spinner or propeller blade, consistent with embodiments of the present disclosure, is illustrated. [Modes for carrying out the invention]

[0031] This disclosure pertains to components of aircraft such as vertical take-off and landing (VTOL) aircraft, including electric vertical take-off and landing (eVTOL) aircraft. For example, the eVTOL aircraft of this disclosure may be intended for frequent (e.g., more than 50 flights per operating day), short-duration flights (e.g., less than 100 miles per flight) over, into, and outside densely populated areas. The aircraft may be intended to carry 4 to 6 passengers or commuters who expect a low-noise and low-vibration experience. Therefore, it may be desirable that the aircraft components be configured and designed to withstand frequent use without wear, that the components generate less heat and vibration, and that the aircraft include mechanisms for effectively controlling and managing the heat or vibration generated by the components. Furthermore, some of these aircraft may be intended to operate in close proximity to each other over congested metropolitan areas. Therefore, it may be desirable that their components be configured and designed to generate low noise levels inside and outside the aircraft and to have various safety and backup mechanisms. For example, for safety reasons, it may be desirable for an aircraft to be propelled by a distributed propulsion system, avoiding the risk of a single point of failure and enabling conventional takeoffs and landings on runways. Furthermore, it may be desirable for an aircraft to be able to safely take off and land vertically in and out of relatively limited spaces (e.g., vertiports, parking lots, or private roads) compared to conventional airport runways, while transporting approximately 4-6 passengers or commuters along with their baggage. These usage requirements may impose design constraints on the size, weight, and operational efficiency (e.g., drag, energy use) of the aircraft, which may affect the design and configuration of aircraft components.

[0032] While applicable to use in conventional aircraft, the disclosed embodiments provide novel and improved aircraft component configurations and / or specific design parameters that differ from those of conventional aircraft components, which are not found in conventional aircraft. Such alternative configurations and design parameters, in combination with those of conventional components, have resulted in the embodiments disclosed herein for various configurations and designs of components for VTOL or eVTOL aircraft.

[0033] In some embodiments, the VTOL or eVTOL aircraft of the Disclosure may be designed to be capable of both vertical and conventional takeoffs and landings, with a distributed electric propulsion system that enables vertical flight, forward flight, and transition. Thrust may be generated by supplying high-voltage power to electric engines of the distributed electric propulsion system, each of which may convert the high-voltage power into mechanical shaft power to rotate a propeller. With regard to safety in passenger transport, the disclosed embodiments implement new and improved safety protocols and system redundancy in the event of failure to minimize any single point of failure in the aircraft propulsion system. Some disclosed embodiments also provide new and improved approaches to meeting aviation and transport laws and regulations. For example, in order to be certified for flight into known icing (FIKI) conditions, the Federal Aviation Administration or its foreign counterpart agency may require that the aircraft be able to reliably prevent or mitigate icing on its surface.

[0034] In some embodiments, the distributed electric propulsion system may include twelve electric engines that can be mounted on forward and aft booms of the aircraft's wings. The forward electric engines may be tiltable during flight between a horizontally oriented position (e.g., for generating forward thrust) and a vertically oriented position (e.g., for generating vertical lift). In a preferred embodiment, for vertical takeoff and landing (VTOL) missions, the forward and aft electric engines may provide vertical thrust during takeoff and landing. During the flight phase when the aircraft is in forward flight mode, the forward electric engines may provide horizontal thrust, while the propellers of the aft electric engines may be retracted to a fixed position to minimize drag. The aft electric engines may be actively retracted while position monitoring is performed. The transition from vertical to horizontal flight and vice versa may be achieved via a tilt propeller subsystem. The tilt propeller subsystem may redirect the thrust, which is primarily vertical during vertical flight mode, to a nearly horizontal direction during forward flight mode. The variable pitch mechanism can change the angle of the propeller-hub assembly blades of the forward electric engine for operation during the hovering, transition, and cruising phases.

[0035] In some embodiments, in conventional take-off and landing (CTOL) missions, the forward electric engines may provide horizontal thrust for fixed-wing take-off, cruising, and landing. In some embodiments, the rear electric engines may not be used to generate thrust during CTOL missions, and the rear propellers may be retracted into a fixed position.

[0036] In some embodiments, the electric propulsion systems described herein may generate thrust by supplying high-voltage (HV) power to electric engines, which then convert the HV power into mechanical shaft driving force used to rotate a propeller. As described above, the aircraft described herein may have multiple electric engines mounted on booms at the front and rear of the wings. The amount of thrust generated by each electric engine may be controlled by torque commands from a flight control system (FCS) via a digital communication interface to each electric engine. Embodiments may include forward-rotating electric engines, and it may be possible to change the orientation or tilt of the forward-rotating electric engines. Additional embodiments include forward-rotating engines, which may be of clockwise (CW) or counterclockwise (CCW) type. The forward-rotating electric engine propulsion subsystem may consist of a multi-blade adjustable-pitch propeller and a variable-pitch subsystem.

[0037] As disclosed herein, an electric engine may include an inverter and motor, or an inverter, gearbox, and motor in various configurations such as a typical configuration described herein. For example, an electric engine may include an electric motor, gearbox, and inverter, all sharing the same central axis. Additionally, the central axis may be configured along the axis of an output shaft extending to the propeller of an aircraft. In such an exemplary configuration, the motor, gearbox, and inverter all share the output shaft as the central axis and are oriented circularly around the output shaft. Additional embodiments may include a motor, gearbox, and inverter mounted sequentially together, or a configuration in which some components, such as a motor and gearbox, are mounted together, and other components, such as an inverter, are located elsewhere, but a wiring system is used to connect the electric engine.

[0038] It is understood that electric engines may generate heat during operation and may be equipped with thermal management systems to ensure that the components of the electric engine do not fail during operation. In some embodiments, a coolant may be used and circulated throughout the individual components of the engine, such as an inverter, gearbox, or motor, through some of the components, or through all of the components of the engine, to help manage the heat present in the engine. Additional embodiments may include using an air-cooling method to cool the electric engine, or using a mixture of coolant and air to manage the heat generated in the electric engine during operation. In some embodiments, the coolant used may also be the same liquid used as a lubricant throughout the inverter, gearbox, or motor. For example, the inverter, gearbox, and motor may be cooled using liquid or air, or a mixture of air and liquid cooling may be used, such as using air cooling to cool the motor and using liquid cooling in the inverter and gearbox, or any other combination of air and liquid cooling may be used over the inverter, gearbox, and motor, or even a subset of their components.

[0039] In some embodiments, oil may be used as a lubricant throughout the electric engine and as a coolant fluid to help manage the heat generated by the engine during operation. In addition to this example, different amounts of oil may be used to function as both a lubricant and a coolant fluid in the electric engine, in combination with one quart, two quarts, or any other amount of oil necessary to lubricate and cool the electric engine, or with or without the assistance of air cooling. In some embodiments, other coolants, such as glycol, may be used as an alternative or in addition to the oil.

[0040] Here, the inventors recognized specific problems associated with flying into known or potential icing conditions. Icing can occur on the lift and tilt propellers of VTOL aircraft during flight. Icing on aircraft, such as propeller blades, control surfaces, and leading-edge surfaces, can degrade aircraft performance and pose safety hazards. Electric aircraft in urban air mobility (UAM) spaces may be particularly susceptible to propeller blade icing problems because their propellers frequently operate at lower revolutions per minute (RPM) than conventional aircraft of comparable size. For example, propellers may be designed to operate at lower speeds to minimize noise generation in urban environments. The lower centrifugal acceleration associated with these lower propeller speeds may increase the likelihood, rate, or magnitude of icing on propeller blades and other surfaces. Certification of aircraft for flight in icing conditions, including intentional or inadvertent flights into known icing conditions, may require ice protection systems or alternatives to manage the effects of propeller icing.

[0041] Furthermore, the design of VTOL aircraft can introduce icing problems that do not occur in conventional aircraft. For example, some VTOL aircraft may include lift propellers that operate only during the climb or hovering phase of flight, or they may be retracted in a stationary configuration, such as during forward fixed-wing flight. A stationary configuration can cause asymmetrical icing on the lift propellers. If the lift propellers are then operating, asymmetrical icing can lead to propeller imbalance and risks to safe flight.

[0042] Additionally, during flight, icing can occur on other surfaces, such as air intakes. Icing can also occur on other surfaces, such as wings or control surfaces. Icing can degrade aircraft performance and pose safety hazards. For example, icing at the intake can restrict airflow to a heat exchanger located downstream of the intake, reducing the cooling efficiency of the heat exchanger and potentially causing overheating in the electric engine, battery, or other heat source. Icing can further affect aircraft performance by reducing lift, increasing weight and drag, and therefore requiring more thrust. Certification for FIKI (Flight to Known Icing) situations may require an ice protection system or alternative means to manage the effects of intake icing.

[0043] Embodiments of this disclosure may provide systems and methods for de-icing and other management of icing on aircraft, such as VTOL aircraft. Management in this context may refer to preventing icing formation and mitigating icing that has already formed. In some embodiments, management may refer to mitigating problems associated with icing, such as causing icing to form on two opposing blades that have a more balanced distribution of ice than would be formed without ice management. Such management systems may utilize high levels of individual motor control available in distributed propulsion architectures of electric aircraft. For example, an ice management cycle may include periodically and alternately modulating propeller parameters on one or more sets of propellers, such as tip Mach number or RPM, to de-icing propellers. Periodic modulation on one propeller may be compensated by a corresponding modulation on another propeller so that icing can be managed without inducing unintended changes in the flight path. For example, modulation may be performed on a symmetrical pair of propellers so that the increased thrust of the symmetrical pair of propellers balances out on either side of the aircraft. Furthermore, other propellers may be controlled to reduce their thrust, thereby achieving an acceptable net change in thrust (e.g., below a predetermined threshold level), or a net change in thrust that is substantially zero or close to zero. For example, the first symmetrical pair of outer propellers may have their RPM increased to achieve a tip Mach number sufficient to prevent or mitigate ice, while the second symmetrical pair of inner propellers may have their RPM decreased by a corresponding amount. In this way, icing can be removed from the outer propellers without causing significant disruption to the flight path or passenger experience. A similar process may then be carried out for the inner symmetrical pair of propellers. In some embodiments, rather than performing periodic modulation with relatively short durations, the symmetrical pairs of propellers may be placed in an extended ice-shedding mode. For example, in some embodiments, the first symmetrical pair of propellers may be kept at high speed to prevent continuous ice formation, while the second symmetrical pair may be completely shut down. This allows some propellers to completely avoid icing, while others can be shut down and ignored.In some embodiments, a shut-down propeller may be periodically modulated to prevent excessive icing, or otherwise simply shut down.

[0044] This system advantageously miniaturizes or eliminates dedicated ice protection systems such as electric heaters, fluid conduits, sumps, or other mechanical ice removal devices. This can reduce the cost and weight of the aircraft while simultaneously reducing the number of power-consuming devices and simplifying the control structure, resulting in a simpler, more efficient, and more fail-safe design. In some embodiments, the lift propeller may operate in a manner similar to that of detaching ice.

[0045] Furthermore, the lift propeller can be periodically rotated during stationary periods of cruising flight so that different lift propeller blades face forward. For example, by substantially equally dividing the amount of forward-facing time between each blade of a two-bladed lift propeller, a three-bladed lift propeller, etc., asymmetry in icing on the blades can be minimized. Periodic rotation of asymmetrical icing can enable maneuvers such as transition and vertical flight after encountering icing, when a retracted propeller is required and may have attached ice.

[0046] Embodiments of the present disclosure may additionally provide systems for managing icing on the surface of a VTOL aircraft, such as an air inlet. For example, an electric aircraft may include an electric engine lubricated or cooled by an oil passage. The oil passage may pass through moving components of the motor assembly, such as rotors and gears, to lubricate and / or cool the components. The oil passage may be further configured to flow over or thermally coupled to stationary components, such as an inverter, to absorb heat from the components. The oil passage may pass through a heat exchanger configured to thermally couple the heat exchanger to the motor assembly. The heat exchanger may discharge the accumulated heat into the airflow from the air inlet. By adding an additional segment to the oil passage, heated oil from the motor assembly may be directed across problem areas vulnerable to icing. For example, the lower lip of an air inlet has been found to be more susceptible to icing than other parts of the inlet, such as the upper inlet. Therefore, the oil passage can bypass the upper lip of the air inlet and target the heated oil in the problem area without incurring unnecessary disadvantages in the form of added weight, conduit piping, oil volume, oil pump size, pressure loss in the passage, or ice-melting capacity of the heated oil.

[0047] Embodiments of the present disclosure may additionally provide an electrical system for managing ice formation. In some embodiments, the ice management system may utilize the power or mechanical drive of the propeller to wirelessly generate heat within moving components of the propeller assembly, such as the propeller blades or spinner. For example, in some embodiments, permanent magnets or electromagnets on the stationary portion of the propeller assembly may be configured to induce a current flow in the winding or to generate eddy current heating within a sheet of conductive material. The current and / or heat may be distributed across the ice-prone surface by, for example, a system of electrically and / or thermally conductive wiring. In some embodiments, an AC circuit may be configured to selectively generate current within, for example, a coil embedded in the blade or spinner, which may then be distributed by a system of conductive wiring.

[0048] Herein, we refer in detail to exemplary embodiments illustrated in the accompanying drawings. The following description refers to the accompanying drawings, and unless otherwise noted, elements numbered the same in different drawings represent identical or similar elements. The implementations shown in the following description of exemplary embodiments do not represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with aspects relating to the subject matter described in the accompanying claims.

[0049] Figures 1A and 1B illustrate a VTOL aircraft 100 in a cruising configuration and a vertical takeoff, landing, and hovering configuration (also referred to herein as a “climb” configuration), respectively, consistent with embodiments of the present disclosure. The aircraft 100 may include a fuselage 102, wings 104 mounted on the fuselage 102, a tail 106, and one or more rear stabilizers 106 mounted on the tail 106 or the rear of the fuselage 102. Multiple lift propellers 112 may be mounted on the wings 104 and may be configured to provide lift for vertical takeoff, landing, and hovering. Multiple tilt propellers 114 may be mounted on the wings 104 and may be tiltable between a cruising configuration, as shown in Figure 1A, in which the multiple tilt propellers 114 provide forward thrust to the aircraft 100 for horizontal flight, and an ascent configuration, as shown in Figure 1B, in which the multiple tilt propellers 114 provide a portion of the lift required for vertical takeoff, landing, and hovering. As used herein, the ascent configuration may refer to the orientation of the tilt propellers in which the thrust of the tilt propellers primarily provides lift to the aircraft. The cruising configuration may refer to the orientation of the tilt propellers in which the thrust of the tilt propellers primarily provides forward thrust to the aircraft. Alternatively, the cruising configuration may refer to a configuration in which the lift propellers are stowed.

[0050] In some embodiments, the lift propeller 112 may be configured to provide only lift, while all thrust is provided by the tilt propeller. Thus, the lift propeller 112 may be in a fixed position and may only generate thrust during takeoff, landing, and hovering. On the other hand, the tilt propeller 114 may be tilted into an upward configuration in which the thrust of the tilt propeller 114 is directed vertically to provide additional lift.

[0051] For forward flight, the tilt propeller 114 can be tilted from an ascent configuration to a cruising configuration. In other words, the pitch and tilt angle of the tilt propeller 114 can be changed from a direction in which the thrust of the tilt propeller is directed vertically (to provide lift during vertical takeoff, landing, and hovering) to a direction in which the thrust of the tilt propeller is directed horizontally (to provide forward thrust to the aircraft 100). The tilt propeller can be tilted around an axis that may be perpendicular to the forward direction of the aircraft 100. When the aircraft 100 is in full forward flight in the cruising configuration, lift can be fully provided by the wings 104. The lift propeller 112, on the other hand, can be shut off or actively retracted. The blades 120 of the lift propeller 112 can be locked in a low-drag position for aircraft cruising. In some embodiments, each lift propeller 112 may have two blades 120 that can be locked for cruising in a minimum drag position where one blade is directly in front of the other blade, as shown in Figure 1A. In some embodiments, the lift propeller 112 has more than two blades. In some embodiments, the tilt propeller 114 includes more blades 118 than the lift propeller 112. For example, as shown in Figures 1A-1B, each lift propeller 112 may include, for example, two blades, and each tilt propeller 114 may include, for example, five blades. In some embodiments, the tilt propeller 114 may have, for example, two to five blades.

[0052] In some embodiments, the aircraft may include only one wing 104 on each side of the fuselage 102 (or a single wing extending across the entire aircraft), with at least a portion of the lift propellers 112 located behind the wing 104 and at least a portion of the tilt propellers 114 located in front of the wing 104. In some embodiments, all of the lift propellers 112 may be located behind the wing 104, and all of the tilt propellers 114 may be located in front of the wing 104. According to some embodiments, all of the lift propellers 112 and tilt propellers 114 may be mounted on the wings, i.e., no lift propellers or tilt propellers may be mounted on the fuselage. In some embodiments, all of the lift propellers 112 may be located behind the wing 104, and all of the tilt propellers 114 may be located in front of the wing 104. According to some embodiments, all lift propellers 112 and tilt propellers 114 may be positioned inside the wingtip 109.

[0053] In some embodiments, the lift propeller 112 and the tilt propeller 114 may be mounted on the wing 104 by a boom 122. The boom 122 may be mounted below the wing 104, above the wing, and / or incorporated into the wing profile. In some embodiments, one lift propeller 112 and one tilt propeller 114 may be mounted on each boom 122. The lift propeller 112 may be mounted at the rear end of the boom 122, and the tilt propeller 114 may be mounted at the front end of the boom 122. In some embodiments, the lift propeller 112 may be mounted in a fixed position on the boom 122. In some embodiments, the tilt propeller 114 may be mounted at the front end of the boom 122 via a hinge. The tilt propeller 114 can be mounted on the boom 122 such that, when in the cruising configuration, the tilt propeller 114 is aligned with the body of the boom 122, forming a continuous extension of the front end of the boom 122 that minimizes drag for forward flight.

[0054] In some embodiments, the aircraft 100 may include, for example, one wing on each side of the fuselage 102, or a single wing extending across the aircraft. According to some embodiments, at least one wing 104 is a high wing mounted on the upper side of the fuselage 102. According to some embodiments, the wing includes control surfaces such as flaps, ailerons, or flaperons. According to some embodiments, the wing may have curved wingtips 109 to reduce drag during forward flight.

[0055] In some embodiments, the rear stabilizer 106 includes control surfaces such as one or more rudders, one or more elevators, and / or one or more combined rudder-elevators. The wing(s) may have any suitable design. For example, the wing may have a tapered leading edge or a tapered trailing edge. In some embodiments, the wing may have a substantially straight leading edge in the central section of the wing 104.

[0056] The aircraft 100 may include at least one door 110 for passenger entry and exit. In some embodiments, the door 110 may be located below and forward of the wing 104, as can be seen in Figures 1A-1B.

[0057] Further considerations of VTOL aircraft can be found in U.S. Patent Publication 2021 / 0362849, which is incorporated in its entirety by reference.

[0058] As discussed above, the embodiments primarily address icing on VTOL aircraft propellers and surfaces equipped with ice management systems, but can be more broadly applied to other types of aircraft.

[0059] A. Exemplary embodiment of an ice management system Figure 2 illustrates an exemplary ice management system 200 consistent with the disclosed embodiments. The ice management system 200 may be part of a distributed propulsion electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. The ice management system 200 may comprise a memory for storing instructions and a processor configured to execute instructions to perform various functions of the ice management system. For example, the ice management system 200 may constitute part of a flight control system (FCS) or associated control architecture. The ice management system 200 may comprise an icing condition identification module 201, a condition estimator 202, and an ice shedding logic module 203. The icing condition identification module 201 may be configured to determine whether an icing condition exists or whether the probability of icing exceeds a predetermined threshold. The icing condition identification module 201 may comprise, for example, a primary ice detector, a manual switch for pilot operation, or an icing estimator. The icing estimator may constitute a part of the FCS configured to determine the likelihood of icing based, for example, meteorological data, geospatial information, information received from authority services such as the Federal Aviation Administration (FAA), or aircraft sensor data. In some embodiments, icing conditions may be determined using an electric engine, propeller, or accelerometer in another module, as will be further considered below with respect to Figure 12. In some embodiments, icing conditions may be determined using an electric engine, propeller, or motor position sensor in another module, as will be further considered below with respect to Figures 13 and 14. In some embodiments, the motion position sensor may include, for example, a resolver. The icing condition identification module 201 may be configured to determine the icing condition based on an icing condition input (such as an input signal from a manual switch module 301 or a primary ice detector module 302, as will be considered below with respect to Figure 3A). Icing conditions include, for example, a state in which the air surrounding the aircraft contains droplets of supercooled liquid water, a state in which the average droplet size meets a predetermined size measurement, a state in which the air temperature reaches a predetermined value, a state in which ice formation is detected on the aircraft, a state in which ice formation is observed on the aircraft, or at least one of other similar conditions. Icing condition input may indicate that an icing condition has been identified or is suspected.Icing condition inputs may be determined from detection systems on the aircraft, on the ground, from a weather service or other third party, or a combination of such detection systems. In some embodiments, icing condition inputs may be based on primary ice detectors. For example, primary ice detectors may include magnetostrictive ice detectors or optical ice detectors. Icing conditions may also be determined based on sensors that monitor the aircraft surface, sensors that monitor the aircraft's physical properties, sensors that monitor the surrounding environmental conditions, and similar sensors. In some embodiments, electric engine accelerometers may be used to measure acceleration to determine whether icing is accumulating on the propellers. In other disclosed embodiments, icing condition inputs may be based on inputs from the flight control system or pilot, such as through a manual switch. A manual switch may be activated by a pilot monitoring the situation. For example, a pilot may activate a manual switch due to temperature, visible moisture, icing on a reference plane, altitude, or similar characteristics. A manual switch may include pilot-operable interfaces such as buttons, switches, touchscreen interfaces, voice commands, or any other systems for inputting commands from a human user of an electric aircraft.

[0060] Once an icing condition is identified, the icing condition identification module 201 may input a signal to the state estimator 202. The state estimator 202 may comprise one or more processors configured to execute code for determining the aircraft state. For example, one or more processors may form part of a flight control system, and the code may include a state estimation algorithm used to determine the aircraft's flight parameters based on the fusion of sensor data from multiple sensors. The state estimator 202 may be configured to determine the aircraft state based on predetermined parameters, such as values ​​of airspeed, altitude, roll, pitch or yaw angle, control surface inclination, etc., in order to determine whether it is safe, feasible, or otherwise acceptable to perform ice management operations. Such values ​​may be determined, for example, by detection or by inferring values ​​from flight control commands. For example, the roll angle may be determined based on a sensor configured to detect the roll angle, or inferred based on flight control commands to maneuver the aircraft to the roll angle. The state estimator 202 may provide an estimate of the aircraft's internal state from measured inputs and outputs of the aircraft. In some embodiments, the state estimator 202 may be configured to perform aircraft integrity checks and isolate or limit the function of ice management operations so that operations are performed only when they are permissible or only to an extent or degree permissible based on the current aircraft state. For example, the state estimator 202 may limit ice management operations when the aircraft is within a specific range of angles, e.g., yaw, pitch, or roll, such as + / - 5 degrees, + / - 10 degrees, or + / - 15 degrees. In some embodiments, the range of angles considered permissible may vary depending on other relevant factors such as airspeed, inclination, etc. In some embodiments, the state estimator 202 may limit ice management operations based on, for example, the state of the power lift enable switch (e.g., when the power lift enable switch is off), the aircraft's operating speed being below a maximum speed threshold, or similar characteristics. Additionally, the state estimator 202 may be configured to perform system and signal checks.For example, the state estimator 202 may verify that all propellers necessary for ice management are operational and enabled.

[0061] The aircraft state may be determined based on, for example, aircraft speed, aircraft mode, aircraft propeller angle, external conditions, or similar parameters. In some embodiments, propeller modulation may be performed only when the aircraft state satisfies predetermined parameters such as control margin status, current bank angle, load factor, vertical airspeed versus commanded airspeed, altitude, propulsion system integrity, signal integrity, and flight mode thresholds. In some embodiments, the ice management system 200 may include a processor configured to determine the aircraft state from a state estimator 202.

[0062] The state estimator 202 may be configured to input commands to the ice removal logic module 203 based, for example, on the determined aircraft state and icing condition inputs. The ice removal logic module 203 may be configured to generate effector commands to trigger one or more ice management cycles. For example, effector commands may include command signals for actuators, electric motors, or other control devices to modulate one or more parameters, such as propellers (e.g., propeller blade pitch angle), motors (e.g., RPM), or tilt actuators (e.g., tilt angle of a tilt propeller system). Modulation of these parameters using effector commands can trigger ice management cycles, and the specific effector commands selected may depend on the type of ice management operation being performed. In some embodiments, for example, the flight control system may have access to a library, reference table, or other data structure, or use a model to define a correspondence between one or more of various propeller modulation parameters and multiple effector commands. This correspondence can then be used to generate multiple effector commands to implement ice management cycles. An ice management cycle may include, for example, ice shedding, prevention, or compensation. Ice shedding may involve removing existing ice on the aircraft. Ice prevention may include preventing ice from forming on the aircraft. Ice compensation may include reducing or offsetting ice formation on the aircraft. An ice management cycle may last for a predetermined period of time, or over a time interval that varies from one cycle to the next, or continue until a predetermined event occurs, such as when a predetermined parameter is met.

[0063] Figure 3A illustrates an exemplary ice management system 300 consistent with the disclosed embodiments. The ice management system 300 may be part of a distributed propulsion electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. In some embodiments, the ice management system 300 may correspond to the ice management system 200 in Figure 2. In some embodiments, the ice management system 300 may constitute part of a flight control system (FCS) or associated control architecture. The ice management system may include a manual switch module 301, a primary ice detector module 302, an icing status identification module 303 configured to output an effective icing status 310 or an ineffective icing status 311, a state estimator 304 configured to output an effective aircraft status input 305 or an ineffective aircraft status 308, an ice detachment logic module 306 configured to output an effector command 307, and a modulation logic disable module 309.

[0064] The manual switch module 301 may include a manual on / off switch, as discussed above. The manual switch may be operated by a pilot monitoring the situation. For example, the pilot may activate the manual switch to indicate the presence of icing conditions, such as when the outside air temperature (OAT) is 0 degrees Celsius. The manual switch module 301 may determine the icing condition input to the icing condition identification module 303.

[0065] The primary ice detector module 302 may include, for example, a primary ice detector. For example, the primary ice detector may include a magnetostrictive ice detector, an optical ice detector, or any detector that can be used to indicate the icing conditions.

[0066] The icing status identification module 303 can determine the icing status based, for example, on icing status inputs from the manual switch module 301 or the primary ice detector module 302, as discussed above. In some embodiments, the icing status identification module 303 may output an effective icing status 310. An effective icing status may indicate the presence of icing, while an invalid icing status may indicate the absence of icing. Different "effective" icing statuses may exist for different types or degrees of icing, and therefore the ice management operations may also differ. The effective icing status 310 may be input to the state estimator 304. In some embodiments, the icing status identification module 303 may output an invalid icing status 311, which is input to the modulation logic invalid module 309.

[0067] The state estimator 304 may be configured to receive an effective icing status input 310 from the icing status identification module 303 and output an effective aircraft status 305 to the effective modulation logic module 306. The effective aircraft status 305 may indicate that the aircraft is in a permissible flight state for propeller modulation for ice management, and the invalid aircraft status 308 may indicate that the aircraft is not in a permissible flight state for propeller modulation for ice management. In some embodiments, the state estimator 304 may be configured to receive an effective icing status status 310 from the icing status identification module 303 and output an invalid aircraft status 308 to the modulation logic invalid module 309.

[0068] The active modulation logic module 306 may be configured to receive an active aircraft state input 305 from the state estimator 304 and determine appropriate propeller modulation parameters based on information such as aircraft state or icing conditions. Propeller modulation parameters may include, for example, modulated status, state, rate, angle, speed, mode, or other aircraft characteristics. For example, propeller modulation parameters may be tip Mach number, revolutions per minute (RPM), aggregate pitch angle, blade pitch angle, torque, or propeller tilt angle. The active modulation logic module 306 may generate a plurality of effector commands 307 corresponding to the propeller modulation parameters. The effector commands 307 may be sent to aircraft effectors, such as electric engines or control surfaces, for example, via the flight control system. In some embodiments, the flight control system may be configured to generate a plurality of effector commands at repeating time intervals. The repeating time interval may include periodically performing propeller modulation over a predetermined duration. For example, if the propeller modulation parameter is a propeller speed parameter such as tip Mach number (ratio of the speed of the propeller tip to the speed of sound in the surrounding air) or revolutions per minute (RPM), the ice management operation may include increasing the RPM for, for example, every 15 seconds, every 2 minutes, every 5 minutes for 2 seconds, or any other suitable combination of frequency and duration appropriate for a particular type of aircraft, aircraft condition, and icing condition. The propeller modulation parameter may be determined based on the effective icing condition 310 and the effective aircraft condition 305.

[0069] The modulation logic disable module 309 may be configured to disable the propeller modulation logic when such propeller modulation is determined to be, for example, unsafe or unnecessary. For example, the modulation logic disable module 309 may receive a disabled icing status input 311 from the icing status identification module 303 indicating that propeller modulation is unnecessary. Alternatively or additionally, the modulation logic disable module 309 may receive a disabled aircraft status input 308 from the status estimator 304 indicating that propeller modulation is unsafe or otherwise undesirable. The modulation logic disable module 309 may be configured to prevent the execution of immediate ice management operations while the ice management system 300 continues to operate.

[0070] Figure 3B illustrates an exemplary ice mitigation method 350 consistent with embodiments of the present disclosure. Method 350 may be performed, for example, in a flight control system comprising an ice management system 200 or 300 as shown in Figure 2 or Figure 3A. In step 351, the ice management system may determine that an icing condition exists. As will be considered throughout the present disclosure, an icing condition may be determined, for example, based on ice detection, or inferred based on other factors such as the likelihood of icing in a given environment.

[0071] In step 352, the ice management system may perform propeller modulation based on the determined icing conditions. For example, the selection of a particular propeller modulation may be based on factors such as the nature of the determined icing conditions or the flight characteristics at the time the icing conditions were determined, in order to generate a first ice relaxation cycle. For example, if it is determined that rapidly changing the propeller blade pitch or increasing the engine RPM can effectively manage the determined icing conditions and be done safely under the current flight characteristics, such propeller modulation may be selected.

[0072] As will be further discussed below, propeller modulation may include step 353 for inducing a first ice management cycle and step 354 for inducing a second ice management cycle. The first ice management cycle may include modulating a first set of one or more propellers (such as the first propeller or a first symmetrical pair of propellers) while the other propellers remain constant or while compensatory modulation is performed to ensure that the flight remains uninterrupted. The second ice management cycle may include modulating a second set of one or more propellers (such as the second propeller or a second symmetrical pair of propellers) while the other propellers remain constant or while compensatory modulation is performed. The first and second ice management cycles may occur at different time intervals. In this way, the various propellers can manage icing conditions "sequentially" without causing significant disruption to the flight.

[0073] Figures 4A–4C show exemplary ice management cycles 402–404 and 410–417 compared to exemplary normal flight conditions 401 according to the disclosed embodiments. Ice management cycles may be performed, for example, according to the ice management systems 200 or 300 of Figures 2 and 3A. The arrows in Figure 4 may represent the relative magnitudes of modulation parameters, such as propeller speed. For example, the propeller speeds of each tilt propeller may be equal, as exemplified in the normal conditions of forward flight 401 when no ice management cycle is occurring, while other configurations may be exemplified by magnitudes above or below the normal conditions observed in 401. For example, some propellers may increase their propeller speed to a level above that shown in normal conditions 401 to dislodge ice, while other propellers may compensate for any change in thrust by decreasing their propeller speed to a level below that shown in normal conditions 401. In some embodiments, multiple effector commands may be executed to induce a first ice management cycle 402 in a first symmetrical pair of propellers 405 of the electric aircraft and a second ice management cycle 403 in a second symmetrical pair of propellers 406 of the electric aircraft, wherein the first ice management cycle 402 occurs at a first time interval different from the second time interval of the second ice management cycle 403. The symmetrical pair of propellers may include a symmetrical pair of tilt propellers or lift propellers. In some embodiments, the symmetrical pair of propellers may be symmetrical with respect to the aircraft body. In some embodiments, the first symmetrical pair of propellers 405 and the second symmetrical pair of propellers 406 may include a pair of tilt propellers. In some embodiments, the first symmetrical pair of propellers 405 may include a first outermost propeller from a first side of the aircraft body and a second outermost propeller from a second side of the aircraft body. The first side and the second side of the aircraft body may refer to opposite sides of the aircraft body in the lateral direction, such as opposite wings. In some embodiments, the second symmetrical pair of propellers 406 may include a third propeller inside the first propeller on the first side of the aircraft body and a fourth propeller inside the second propeller on the second side of the aircraft body.

[0074] The disclosed embodiments include management cycles occurring at different time intervals. In some embodiments, the first management cycle 402 may occur at a different time interval than the second management cycle 403. For example, the different time intervals may include multiple different intervals with no overlap, or may represent time intervals with different start or stop points that overlap. For example, one propeller pair may rise while another propeller pair descends so that their ice management cycles overlap. In some embodiments, multiple effector commands 307 may be configured to trigger the first ice management cycle 402 and the second ice management cycle 403 at non-overlapping time intervals. The different first and second time intervals may include different start and stop times, different durations of the ice management cycles, different time spans, different periods, and so on.

[0075] The disclosed embodiments include additional ice management cycles corresponding to additional symmetrical pairs of propellers. In some embodiments, a plurality of effector commands are further configured to trigger a third ice management cycle 404 in a third symmetrical pair of propellers 407 of the electric aircraft, the third ice management cycle 404 occurring in a third time interval, the third time interval being different from the first and second time intervals. In some embodiments, the third symmetrical pair of propellers 407 may include a fifth propeller between the first and third propellers on the first side of the aircraft body, and a sixth propeller between the second and fourth propellers on the second side of the aircraft body. It should be understood that the ice management cycles are identified as first, second, and third for differentiation purposes and do not indicate a particular order.

[0076] Embodiments disclosed include changing the propeller modulation value of a set of propellers by a predetermined value. For example, the propeller modulation parameter may include RPM, and during a first ice management cycle 402, the RPM of a first symmetrical pair of propellers 405 may be increased by a predetermined amount during a first time interval. For example, the RPM may be increased to achieve a predetermined tip Mach number of the propeller blades, such as 0.5, 0.6, or higher, or another value sufficient to mitigate or prevent icing. For example, under normal flight conditions, a typical eVTOL or another distributed electric propulsion aircraft may operate at a low Mach number, for example, about 0.3 or 0.4, to avoid generating excessive noise. However, according to embodiments of the Disclosure, the RPM may be temporarily modulated to a higher value in a propeller pair. For example, if only one propeller pair is modulated at a time, the ice can be managed without generating unacceptable levels of noise or significant interference to flight characteristics. In some embodiments, the modulation may be performed on two or more pairs, but fewer than all pairs. In some embodiments, all propeller pairs configured for forward flight may be modulated simultaneously for a short period of time, despite increased noise or interference with flight characteristics. In some embodiments, the modulation may be compensated for by the operation of other propellers or by activating the flight control surface.

[0077] In some embodiments, the RPM of the first symmetrical pair of propellers 405 may be increased by at least, for example, 50 percent or 80 percent. In some embodiments, the RPM of the first symmetrical pair of propellers 405 may be increased by at least, for example, 50 percent or 80 percent of the maximum available RPM during a first time interval. In some embodiments, other symmetrical propellers may have their RPM reduced during the first ice management cycle 402 to compensate for the increased RPM of the first symmetrical pair of propellers, as indicated by the relatively short arrows in pairs 406 and 407. In some embodiments, other compensatory actions may be taken, such as activating control surfaces, so that the ice management cycle can be performed without causing a substantial interruption to the flight path or passenger experience.

[0078] In some embodiments, the propeller modulation parameters may include the blade pitch angle, and during the first ice management cycle 402, the blade pitch angle of the first symmetrical pair of propellers 405 may change by at least, for example, 5, 10, or 20 degrees during the first time interval. For example, changing the blade pitch angle may induce a higher aerodynamic blade load. For example, in some embodiments, the blade pitch angle may be changed from the first blade pitch angle to the second blade pitch angle by, for example, + / - 5 degrees, for a period of more than 10 seconds, such as about 30 seconds or more. In some embodiments, the first ice management cycle 402 may include changing the blade pitch angle of the first symmetrical pair of propellers 405 by at least 5 degrees at least four times during the first time interval. The first interval may be, for example, less than 5 seconds, less than 10 seconds, or include any other duration. Rapid changes in the blade pitch angle may cause the ice to sway gently or be exposed to changing airflow.

[0079] In some embodiments, the propeller modulation parameter may include torque, and the first ice management cycle 402 may include changing the torque values ​​of a first symmetric pair of propellers 405 by a predetermined amount during a first time interval. In some embodiments, the ice management cycle may include rapid longitudinal acceleration to shake off ice accumulation from the propeller blades. For example, an electric engine in a distributed propulsion system may be able to induce such rapid changes by reversing direction, braking, or otherwise decelerating the propellers. In some embodiments, the electric engine may use regenerative braking to collect energy from the propellers while achieving negative acceleration to manage the ice. In some embodiments, the first ice management cycle 402 may include increasing the torque of a first symmetric pair of propellers 405 by at least, for example, 50 percent or 80 percent. In some embodiments, the first ice management cycle 402 may include increasing the torque of a first symmetrical pair of propellers 405 from an initial torque value to within 50 percent or 80 percent of the maximum torque, and during a first time interval, decreasing the torque of the first symmetrical pair of propellers 405 to less than 50 percent, 30 percent, 20 percent, or 10 percent of the maximum torque. For example, the initial torque value may be the torque value applied before the torque value is changed at the start of the ice management cycle.

[0080] In some embodiments, the propeller modulation parameter may be the propeller tilt angle, and the first ice management cycle 402 may include changing the propeller tilt angle of a first symmetric pair of propellers 405 by a predetermined amount, such as at least 5, 10, 20, or 30 degrees, during a first time interval. The tilt angle may be changed, for example, to produce edge-directed flow, which may be advantageous for optimizing the ice shedding trajectory. In some embodiments, the first ice management cycle 402 further includes increasing the second RPM of a second symmetric pair of propellers 406 during the first time interval, or performing another compensatory action, such as those considered above. Alternatively, the tilt angle modulation may function as compensation for another ice shedding cycle, or two complementary ice shedding cycles may occur together. For example, changing the tilt angle may generate a thrust vector with a vertical component, which may help compensate for reduced lift from simultaneous modulation occurring on the same or another propeller pair.

[0081] Further ice modulation cycles may be performed for other propeller symmetric pairs in a manner corresponding to the description of the first symmetric pair of propellers 405. While ice management cycles are exemplified with respect to tilt propellers, embodiments of this disclosure are not limited thereto. For example, in some embodiments, lift propellers may be modulated alternatively to, or in addition to, tilt propellers, according to the propeller modulation parameters described above.

[0082] Additionally, modulation does not necessarily have to occur in symmetric pairs. Figure 4B illustrates a further set of ice management cycles 410–413 consistent with embodiments of the present disclosure. As shown in Figure 4B, modulation cycles may occur in symmetric sets rather than symmetric pairs. That is, the net thrust or other parameters from a first set 408 of propellers on the first side of the aircraft body may be substantially equal to a second net thrust or other parameters from a second set 409 of propellers on the second side of the aircraft body. On the other hand, the individual modulation parameters on symmetric pairs do not have to be equal in magnitude. Examples of such modulations are illustrated in ice management cycles 410–413.

[0083] As seen in ice management cycle 410, the intermediate propeller of the first set 408 may be modulated to a first RPM (or other modulation) value, and the innermost propeller of the second set 409 may be modulated to a second higher RPM (or other modulation) value. Because the two modulated propellers are located at different distances from the center of the aircraft, they may exert different torques on the vertical axis (off-page in Figure 4B) for a given thrust. By modulating the two propellers by different amounts, the net effects of the first and second sets 408 and 409 of propellers can be balanced. Ice management cycle 411 illustrates the opposite modulation to ice management cycle 410, where the intermediate propeller of the second set 409 may be modulated to a first RPM value, and the innermost propeller of the first set 408 may be modulated to a second higher RPM value.

[0084] As seen in ice management cycle 412, a single large propeller modulation, such as that of the outermost propeller of the first set 408, can be offset by the uniform propeller modulation of all the propellers of the second set 409. This allows the first and second sets of propellers 408 and 409 to balance each other while minimizing the number of propellers that require high-amplitude modulation. Ice management cycle 413 illustrates the opposite modulation to ice management cycle 412, where the outermost propeller of the second set 409 can be offset by the uniform propeller modulation of all the propellers of the first set 408.

[0085] In some embodiments, more complex modulation distributions may be tuned to allow modulation during aircraft conditions that might otherwise be considered invalid or suboptimal, such as during banking, so it may be preferable to modulate the propellers in a symmetric set rather than a symmetric pair, as discussed above. In some embodiments, the modulation may not be symmetric at all in order to enable modulation during such aircraft conditions. For example, in some embodiments, an aircraft condition / evaluation system (e.g., 304 in Figure 3A) may determine an aircraft condition that is invalid for symmetric pair modulation, but nevertheless valid for alternative modulations such as symmetric set modulation or asymmetric modulation.

[0086] Figure 4C illustrates a further set of ice management cycles 414–417 consistent with embodiments of the present disclosure. Rather than performing periodic modulation of relatively short durations, propeller symmetric pairs may be placed in an extended ice-shedding mode. For example, in some embodiments, a first symmetric pair of propellers may be kept at high speed to prevent continuous ice formation, while a second symmetric pair may be completely shut down. This may allow some propeller symmetric pairs, such as propeller pairs 405 and 407, to completely avoid icing by operating continuously at a level that prevents or reduces icing, as can be seen in management cycle 414. Other propeller pairs, such as propeller pair 406, may be shut down and ignored, as can be seen in management cycle 414. The same may be true for ice management cycle 415, where propeller pairs 405 and 406 may operate continuously at a level that prevents or reduces icing, while propeller pair 407 may be shut down. Alternatively, as shown in ice management cycle 417, propeller pairs 405 and 406 may operate continuously at two different levels to prevent or reduce icing, while propeller pair 407 may be shut down.

[0087] In some embodiments, a single propeller pair may operate while other propellers are shut down. For example, in ice management cycle 416, propeller pair 406 may operate continuously while both propeller pairs 405 and 407 are shut down. In some embodiments, propellers shut down in ice management cycles 414-417 may be periodically modulated according to the embodiments considered above to prevent excessive icing and may be shut down at other times. For example, if the propeller pair is a lift propeller pair, the lift propellers may be shut down for extended periods when retracted into the cruising configuration. Therefore, in some embodiments, propeller modulation may include periodically rotating one or more lift propellers in the cruising configuration and then returning them to their stationary retracted positions.

[0088] Ice management cycles 414–417 can concentrate RPM and engine heat on a small number of propellers, which may be advantageous when used in conjunction with other ice management techniques (such as transferring engine heat to surfaces prone to ice formation, or generating electric heating from propeller motion, both of which are considered below). Furthermore, although the drawings illustrate three tilt propeller pairs and three lift propeller pairs, embodiments are not limited thereto. Additionally, some modulation parameters are tuned to specific propeller types such as tilter, lifter, and variable-pitch propellers, while other parameters are general to many types. Thus, ice management cycles according to embodiments of the present disclosure can be implemented using any suitable number or type of propellers in a distributed propulsion system such as a VTOL or CTOL aircraft.

[0089] B. Exemplary Embodiments for Managing Asymmetric Icing Asymmetrical icing can occur on fixed propellers during flight. For example, if a lift propeller remains stationary during cruising flight, more ice may form on the forward-facing blades than on the rear-facing blades, resulting in asymmetrical ice accumulation. If asymmetrical ice accumulation exists on a fixed propeller and the propeller subsequently operates, the asymmetrical ice accumulation can create an unfavorable propeller imbalance and flight safety risk. The disclosed embodiments include an ice management cycle in which a fixed propeller, such as a lift propeller, rotates periodically to distribute and / or reduce (e.g., minimize) the icing evenly.

[0090] Figure 5 illustrates an exemplary system for managing asymmetric icing 500 consistent with embodiments of the present disclosure. The ice management system 500 may be part of a distributed propulsion electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. The ice management system 500 may be similar to the ice management system 200 in Figure 2, but may be applied to ice management of a lift propeller. For example, the ice management system 500 may constitute part of a flight control system (FCS) or associated control architecture. In some embodiments, the ice management system 500 may correspond to, form part of, or be integrated with the ice management systems 200 and 300 in Figures 2-3. The ice management system 500 may comprise an icing status identification module 501, a state estimator 502, and an ice shedding logic module 503. The icing status identification module 501 may include a primary ice detector or a manual switch. The icing status identification module 501 may be configured to determine the icing status based on an icing status input. The state estimator 502 may be configured to determine the aircraft state.

[0091] The ice removal logic module 503 may be configured to generate effector commands to trigger multiple ice management cycles. The ice removal logic module 503 may also send effector commands 307 to periodically rotate the propeller. For example, in the two-blade configuration shown in the figure, the ice removal logic module 503 may send effector commands 307 to rotate the propeller by approximately 180 degrees. In some embodiments, such as a three-blade lift propeller, the ice removal logic module 503 may send effector commands 307 to rotate the propeller by approximately 60, 90, or 120 degrees. Generally, the lift propeller may be rotated periodically during stationary periods of cruising flight so that different lift propeller blades face forward, for example, in some embodiments, by multiples of 30 degrees for propellers with two, three, four, or six blades. For example, asymmetry in ice formation on the blades can be minimized by substantially equally distributing the amount of forward-facing time among each blade of a two-blade lift propeller, a three-blade lift propeller, and so on. Alternatively, ice formation can be evenly distributed by rotating at least some of the propeller blades slowly and continuously. For example, in some embodiments, propeller blades may rotate between 6 and 120 RPM, or slower than other propeller blades.

[0092] Figure 6 illustrates an exemplary ice management system 600 for managing asymmetric icing, consistent with the disclosed embodiments. The ice management system 600 may be part of a distributed propulsion electric aircraft, such as the VTOL aircraft 100 in Figures 1A-B. The ice management system 600 may be similar to the ice management system 300 in Figure 3A, but may be applied to ice management of a lift propeller. The ice management system 600 may constitute part of a flight control system (FCS) or associated control architecture. The ice management system may include a manual switch module 601, a primary ice detector module 602, an icing status identification module 603 configured to output an effective icing status 610 or an ineffective icing status 611, a status estimator 604, an effective aircraft input 605 configured to output an effective aircraft status input 605 or an ineffective aircraft status 608, an ice detachment logic module 606 configured to output an effector command 607, and a modulation logic disable module 609.

[0093] The manual switch module 601 may include a manual on / off switch. The manual switch can be operated by a pilot monitoring the situation. Based on the state of the manual switch, the manual switch module 601 may determine the icing condition input of the icing condition identification module 603.

[0094] The primary ice detector module 602 may include a primary ice detector such as a magnetostrictive ice detector or an optical ice detector. The ice detector module 602 can determine the ice formation state input of the ice formation state identification module 603.

[0095] The icing status identification module 603 can determine the icing status based on the icing status input from the manual switch module 601 and the primary ice detector module 602.

[0096] The state estimator 604 may be configured to receive the effective icing status 610 from the icing status identification module 603 and output the effective aircraft status input 605 to the effective modulation logic module 606.

[0097] The active modulation logic module 606 may, for example, determine appropriate propeller modulation parameters based on information about the aircraft condition or icing conditions, and generate a number of effector commands 607 corresponding to the propeller modulation parameters. The effector commands 607 may be sent to aircraft effectors, such as electric engines or control surfaces, via, for example, the flight control system. The effector commands 607 may include commands for icing management cycles and commands for initiating icing management cycles in asymmetric icing embodiments.

[0098] The modulation logic disable module 609 may be configured to take invalid icing conditions 611, invalid aircraft conditions 608, or both invalid icing conditions 611 and invalid aircraft conditions 608 as inputs. The modulation logic disable module 609 continuously monitors the icing conditions and aircraft conditions.

[0099] Figures 7A–7C illustrate exemplary ice management cycles, such as the first, second, and third lifter ice management cycles 702–704, compared to a normal operating period 701, consistent with embodiments of the present disclosure. Unlike the modulation cycles in Figures 4A–4C, which may be performed on the lift propeller as discussed above, the lifter ice management cycles 702–704 may be designed to manage asymmetric icing. Asymmetric icing can occur on a lift propeller during cruise flight, for example, when one blade is facing forward into the airflow while the other blades are facing backward or obliquely, and remain fixed in a retracted position for extended periods. The lifter ice management cycles 702–704 may be performed, for example, using the ice management systems 500 and 600 in Figures 5–6. Embodiment 7A illustrates an example where lift propeller modulation is performed while the tilt propeller is operating normally, and Figures 7B and 7C illustrate their same operation when performed simultaneously with tilt propeller modulation.

[0100] In some embodiments, the first lifter ice management cycle 702 may include rotating a first symmetrical pair of outermost lift propellers 705 between a first angular position and a second angular position. For example, the first angular position may correspond to each pair of first propeller blades substantially facing the front of the aircraft, and the second angular position may correspond to each pair of second propeller blades substantially facing the front of the aircraft. The second propeller blade may be the next propeller blade in the direction of rotation, or there may be intervening blades. For example, the first angular position may be offset from the second angular position by an integer multiple of, for example, about 180, 60, 45, or 36 degrees for propellers having two, three, four, or five blades, respectively. Similar to the first lifter ice management cycle 702, the second lifter ice management cycle 703 may include rotating a second symmetrical pair of intermediate lift propellers 706 between a first angular position and a second angular position. A third lifter ice management cycle 704 may include rotating a third symmetrical pair of innermost lift propellers 707 between a first angular position and a second angular position. In some embodiments, multiple symmetrical pairs of lift propellers may be rotated simultaneously.

[0101] In some embodiments, ice management may be performed using an oscillator coupled to the propeller, for example, at the propeller shaft, hub, blades, or other components. The oscillator may be configured to vibrate the lift propeller at a selected resonant frequency of the propeller blades. This causes the propeller blades to vibrate strongly, potentially breaking up the ice formed on them. While this may be a favorable method for handling stationary propellers such as lifters, it should be understood that in some embodiments, the oscillator may be applied to tilers.

[0102] As illustrated in Figure 7A, the symmetrical pair of tilt propellers 405-407 may continue to operate normally, similar to the normal operating period 401 shown in Figure 4A, while the lift propellers rotate between different angular positions. However, in some embodiments, while the lift propellers are modulated, multiple effector commands 607 may modulate the symmetrical pair of tilt propellers 405, 406, or 407 to manage the ice or offset the interference caused by the modulation of the lift propellers. For example, as can be seen in Figure 7B, multiple effector commands 607 may induce a first lifter ice management cycle 702 while simultaneously performing a first ice management cycle 402, as considered with respect to Figure 4A. Similarly, a second lifter ice management cycle 703 may be performed while simultaneously performing a second ice management cycle 403, as considered with respect to Figure 4A. Furthermore, the third lifter ice management cycle 704 can be performed, for example, while simultaneously performing the third ice management cycle 404, as considered with respect to Figure 4A. Performing these simultaneous cycles allows for the modulation of the tilt propeller immediately preceding the corresponding modulated lift propeller.

[0103] Alternatively, as shown in Figure 7C, in some embodiments, the tilt propeller modulation may be spatially offset from the lifter modulation such that the modulated tilt propeller is not always directly in front of the modulated lift propeller. For example, the first lifter ice management cycle 702 may be performed simultaneously with, for example, a third ice management cycle 404, as considered with respect to Figure 4A. Similarly, the third lifter ice management cycle 704 may be performed simultaneously with, for example, the first ice management cycle 402, as considered with respect to Figure 4A. Nevertheless, the intermediate lift propellers and tilt propellers 706 and 406 can still be modulated simultaneously. For example, the second lifter ice management cycle 703 may be performed simultaneously with the second ice management cycle 403, for example, in the same manner as considered with respect to Figure 7B above.

[0104] C. Exemplary Embodiments for Controlling Icing on Air Inlets and Other Surfaces Figures 8A–8C illustrate exemplary propeller systems 800A–800C configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller systems 800A–800C may comprise a portion of an electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller systems 800A–800C may comprise a propeller 801, a motor assembly 802, a heat exchanger 803, an oil passage 804 including first and second segments 811 and 812, a pump 840, and a nacelle 805. The motor assembly 802 may comprise various subsystems, such as a motor 835, a gearbox 836, or an inverter 837. The components of the motor assembly are shown in a specific order, but embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the gearbox 836 may be located closer to the propeller 801 than the motor 835, or the inverter 837 may be located elsewhere.

[0105] The disclosed embodiments include a motor assembly 802 coupled to a propeller 801. An oil passage 804 may be configured to thermally couple a heat exchanger 803 to the motor assembly 802. A nacelle 805 may be mechanically coupled to the motor assembly 802, and the nacelle 805 may include an air inlet 806. In some embodiments, mechanical coupling to the motor assembly may include direct connection to the motor assembly. The oil passage 804 may lubricate and / or cool components by passing through or thermally coupling to components within the subsystems of the motor assembly 802. It should be understood that the oil flow 804 is illustrated in a highly schematic manner to show that, in some embodiments, the passage 804 may reach or thermally communicate with each subsystem of the motor assembly 802. It should not necessarily be interpreted as a circumferential loop or a single continuous series flow. For example, in some embodiments, oil may be divided and distributed to various components to lubricate them and collect heat from them, and the oil may then be collected in a sump (not shown with respect to Figure 15, discussed below) and cycled again by, for example, a pump 840. For example, the pump 840 may include, for example, a gear-driven pump. For example, the pump 840 may be coupled to a gearbox 836 so that the pump 840 operates when the motor assembly 802 is active. Alternatively, the pump 840 may include an independent pump powered by, for example, an inverter 837. In some embodiments, the oil may be forced to flow through an oil passage 804 without using a dedicated pump.

[0106] The oil passage 804 may pass through the heat exchanger 803 to thermally couple the heat exchanger 803 to the motor assembly 802. For example, the heat exchanger 803 may discharge the accumulated heat into the airflow 807 from the air inlet 806. The air inlet 806 may include a lower lip 809 with respect to the forward flight configuration. The lower lip 809 may be further from the motor assembly 802 than the upper lip 810, which is on the opposite side of the lower lip 809.

[0107] The oil passage 804 may include a first segment 811 and a second segment 812. In some embodiments, the oil passage 804 may include a third segment (not shown in Figures 8A and 8B). The first segment 811 may pass through the motor assembly 802. The second segment 812 may pass through the heat exchanger 803. The third segment may pass along the lower lip 809. In some embodiments, the oil passage 804 may bypass the upper lip 810.

[0108] In some embodiments, a thermally conductive material 808 may be included between the motor assembly 802 and the upper lip 810. The thermally conductive material 808 may be configured to conduct heat from the motor assembly 802 to the upper lip 810. Additionally or alternatively, in some embodiments, the nacelle 805 may include a first material, and the thermally conductive material 808 may include a second material different from the first material. The second material may have a higher thermal conductivity than the first material. The second material with higher thermal conductivity may allow heat to be transferred more quickly or efficiently from one place to another than the first material, while the first material of the nacelle may be desired for other characteristics such as cost, manufacturability, weight, or durability.

[0109] In some embodiments, similar to the propeller system 800B shown in Figure 8B, the thermal conductive material 808 may extend along the two sides of the air inlet 806 between the upper lip 810 and the lower lip 809 to conduct heat around the air inlet 806. In some embodiments, the thermal conductive material may surround the air inlet 806. Alternatively, similar to the propeller system 800C shown in Figure 8C, the thermal conductive material 808 may extend from the inside of the motor assembly 802 to the outside of the motor assembly 802 to better conduct the heat generated inside the motor assembly. The thermal conductive material 808 extending from the inside of the motor assembly 802 to the outside of the motor assembly 802 may include, for example, a plate extending from the inside of the motor assembly 802 to the outside of the motor assembly 802. The plate may be positioned between two modules of the motor assembly, such as between the motor and the gearbox, or between the gearbox and the inverter. Alternatively or additionally, the thermally conductive material 808 may be wrapped around the motor assembly 802.

[0110] Figures 9A–9H illustrate exemplary propeller systems 900A–900H configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller systems 900A–900H may comprise part of an electric aircraft, for example, the VTOL aircraft 100 in Figures 1A and 1B. The propeller systems 900A–900H may comprise a propeller 901, a motor assembly 902 comprising, for example, a motor 935, a gearbox 936, and an inverter 937, a heat exchanger 903, an oil passage 904 including first, second, and third segments 911–913, a pump 940, and a nacelle 905, the nacelle 905 may include an air inlet 906 comprising an upper lip 910 and a lower lip 909 and configured to direct airflow 907 towards the heat exchanger 903, and one or more valves 914.

[0111] The lower lip 909 may be positioned opposite the upper lip 910 with respect to gravity and below the upper lip 910 when the propeller 901 is oriented in a forward flight configuration. The lower lip 909 may be positioned further from the motor assembly 902 than the upper lip 910 along the radial direction R of the propeller 901.

[0112] As indicated by the dashed lines and arrows, the oil passage 904 may circulate through various parts of the motor assembly 902 and the nacelle 905. For example, the oil passage 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. In some embodiments, the third segment 913 may extend along the lower surface of the nacelle 905 with respect to the forward flight configuration. The third segment 913 may further branch off from the second segment 912 in the oil flow direction 904 and return to the second segment 912 in the oil flow direction 904. For example, in Figure 9A, the oil flow direction 904 is in the direction indicated by the arrow. In a further embodiment, the first segment 911 may flow into the second segment 912 in the oil flow direction 904 and return from the second segment 912 in the oil flow direction 904.

[0113] In some embodiments, the third segment 913 may branch off from the relatively high-temperature side of the oil flow path and return to the relatively low-temperature side of the oil flow path. For example, the third segment 913 may branch off from the second segment 912 near the inlet side of the heat exchanger 903 and return to near the outlet side of the heat exchanger 903.

[0114] The propeller system 900A may further include a first flow control valve 914. The first flow control valve 914 may be configured to regulate the oil flow rate through the third segment 913. In some embodiments, the first flow control valve 914 may be configured to selectively block the oil flow to or from the third segment 913. In further embodiments, the propeller system 900A may include a second flow control valve 915. The first flow control valve may be located on the inlet side of the third segment 913, and the second flow control valve 915 may be located on the outlet side of the third segment 913. In some embodiments, the flow control valve may be configured to selectively increase or decrease the flow rate through the third segment 913. For example, the flow may be turned on or off, or its flow rate may be adjusted up or down based on the icing conditions determined as discussed above, or based on a dedicated air inlet ice sensor. In some embodiments, the first or second flow control valve 914 / 915 may include a check valve or other unidirectional flow device configured to maintain the flow of oil in a desired direction. Generally, any segment or joint between segments may include such a flow control valve.

[0115] In addition to ice management, additional oil flow channel segments, such as the third segment 913, can advantageously provide more cooling surface for dissipating heat from the oil. This can reduce the demands on the heat exchanger, thereby allowing for a reduction in the size of the heat exchanger or an improvement in overall cooling efficiency. However, as mentioned above, this can also result in greater complexity, conduits, oil volume, and pump mass. Therefore, as considered above, in some embodiments, it may be beneficial to limit the additional oil flow channel segments to target the surface most prone to ice accumulation, and similarly, to provide the best additional cooling area. For example, in some embodiments, if ice accumulation is more common, it may be advantageous to target the lower lip of the air inlet.

[0116] In Figure 9A and other figures, the third segment 913 may be shown as branching off, for example, from between the pump 940 and the heat exchanger 903. However, embodiments of the present disclosure are not limited thereto. For example, as considered above with respect to Figure 8A, the pump 940 may not be present, or may not be coupled to the gearbox 936, or may be located elsewhere. Furthermore, in some embodiments, the third segment may extend, for example, from the outlet side of the heat exchanger 903. In some embodiments, for example, the third segment may extend in series from the outlet side of the heat exchanger 903 to, for example, the inverter 937 or another part of the oil passage 904.

[0117] Figure 9B illustrates an exemplary propeller system 900B configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 900B may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. For example, the propeller system 900B may comprise the components considered above with respect to Figure 9A, and further components considered below.

[0118] The oil flow path 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. The third segment 913 may branch off from the first segment 911 in the direction of the oil flow 904 at the first segment outlet point 916. In some embodiments, the first segment outlet point 916 may be located on the output side of the pump 940. The third segment 913 may flow into the second segment 912 in the direction of the oil flow 904. For example, as shown in Figure 9B, the third segment 913 may be supplied to the second segment 912 in the direction of the arrow. In a further embodiment, the third segment 913 may return to the first segment 911 in the direction of the oil flow 904 at the third segment outlet point 917, and the third segment outlet point 917 is downstream of the first segment outlet point 916 in the direction of the oil flow 904.

[0119] Figure 9C illustrates an exemplary propeller system 900C configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 900C may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 900C may comprise the components discussed above with respect to Figures 9A-9B, and further components discussed below.

[0120] The oil flow path 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. The third segment 913 may branch off from the first segment 911 in the direction of the oil flow 904 at the first segment outlet point 916. The third segment 913 may return to the first segment 911 in the direction of the oil flow 904 at the third segment outlet point 917. The third segment outlet point 917 may be downstream of the first segment outlet point 916 in the direction of the oil flow 904. In some embodiments, the third segment outlet point 917 is upstream of the second segment 912 in the direction of the oil flow 904.

[0121] Figure 9D illustrates an exemplary propeller system 900D configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 900D may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 900D may comprise the components discussed above with respect to Figures 9A–9C, and further components discussed below.

[0122] The oil passage 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. In some embodiments, the third segment 913 may be connected in series within the first segment 911. In other words, in some embodiments, a first portion of the first segment 911 may flow into the third segment 913, and the third segment 913 may flow into a second portion of the first segment 911. An alternative series connection is shown in Figure 9H, where the third segment 913 extends along the air inlet 906 and the lower surface of the nacelle 905, into the heat exchanger inlet 920, through the heat exchanger, and toward the heat exchanger outlet 921.

[0123] Figure 9E illustrates an exemplary propeller system 900E configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 900E may comprise part of an electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 900E may comprise the components discussed above with respect to Figures 9A–9D, and further components discussed below.

[0124] The oil flow path 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. In some embodiments, the third segment 913 may return to the first segment 911 in the direction of the oil flow 904 at a third segment outlet point 917, the third segment outlet point 917 may coincide with or be called the first segment inlet point. The first segment inlet point 917 may be downstream of the first segment outlet point 916 in the direction of the oil flow 904. In some embodiments, the first segment outlet point 916 may be located near the inlet of the heat exchanger 903. In some embodiments, the first segment inlet point 917 may be located near the outlet of the heat exchanger 903. In some embodiments, the inlet point 917 of the first segment may be located upstream of the second segment 912 in the direction of the oil flow 904. Additionally, in some embodiments, a first portion of the first segment 911 may flow into the third segment 913, and the third segment 913 may flow into the second portion of the first segment 911.

[0125] Figure 9F illustrates an exemplary propeller system 900F configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 900F may comprise part of an electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 900F may comprise the components discussed above with respect to Figures 9A–9E, and further components discussed below.

[0126] The oil passage 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. In some embodiments, the third segment 913 may pass around substantially the entire air inlet 906. For example, the third segment 913 may be divided into subsegments at a first point on the air inlet 906, such as the upper lip 910, and the subsegments may merge at a second point on the air inlet 906, such as the lower lip 909.

[0127] Figure 9G illustrates an exemplary propeller system 900G configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 900G may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 900G may comprise the components discussed above with respect to Figures 9A–9F, and further components discussed below.

[0128] The oil passage 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. In some embodiments, the third segment 913 may pass substantially around the air inlet 906 in a single circuit.

[0129] Figure 9H illustrates an exemplary propeller system 900H configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 900H may comprise part of an electric aircraft, for example, the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 900E may comprise the components considered above with respect to Figures 9A–9G, and further components considered below.

[0130] The oil passage 904 may include a first segment 911, a second segment 912, and a third segment 913. The first segment 911 may pass through the motor assembly 902. The second segment 912 may pass through the heat exchanger 903. The third segment 913 may pass along the lower lip 909. In some embodiments, such as those shown in Figure 9H, the third segment 913 may extend along the air inlet 906 in series from the first segment 911 to the second segment 912.

[0131] Figures 10A and 10B illustrate exemplary propeller systems 1000A and 1000B configured to manage icing on the surface of an electric aircraft, respectively, consistent with the disclosed embodiments. Propeller systems 1000A and 1000B may comprise a part of an electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. Propeller systems 1000A and 1000B for managing ice formation on the surface of an electric aircraft may comprise a propeller 1001, a motor assembly 1002 having, for example, a motor 1035, a gearbox 1036, and an inverter 1037, a heat exchanger 1003, an oil passage 1004 including first and second segments 1011 and 1012, a pump 1040, and a nacelle 1005, the nacelle 1005 may comprise an air inlet 1006 having an upper lip 1010 and a lower lip 1009 and configured to direct airflow 1007 toward the heat exchanger 1003, and a heat pipe circuit 1013.

[0132] The components of propeller systems 1000A and 1000B may be similar to those of propeller systems 900A to 900H discussed above, with the reference numbers beginning with "10" instead of "9". For example, the oil passage 1004 in Figures 10A to 10B may be similar to the oil passage 904 in Figures 9A to 9H. Therefore, the descriptions of some components can be omitted here. However, a notable difference between Figures 10A to 10B is that the heating function previously performed by the third segment 913 of the oil passage 904 may instead be performed by the heat pipe circuit 1013.

[0133] For example, the oil passage 1004 may be configured to thermally couple the heat exchanger 1003 to the motor assembly 1002. The oil passage 1004 may include a first segment 1011 and a second segment 1012. The heat pipe circuit 1013 may include a heat pipe as a third segment independent of the oil passage. For example, the heat pipe circuit 1013 may be configured to circulate a phase-change material. The use of a heat pipe may allow heating of the air inlet without circulating oil to the inlet. This may reduce the total amount of oil contained in the aircraft and mitigate the risk of oil leaks.

[0134] The heat pipe circuit 1013 may be configured to collect heat from a heat source and discharge that heat to the lower lip 1009. The first segment 1011 of the oil passage 1004 may pass through the motor assembly 1002, and the second segment 1012 may pass through the heat exchanger 1003. In some embodiments, the heat source may include the heat exchanger 1003, as shown in Figure 10A. For example, the heat pipe circuit 1013 may be thermally coupled to the heat exchanger 1003 by being arranged in close thermal contact or by integrating the heat pipe circuit with the heat exchanger 1003. In some embodiments, the heat source may include the motor assembly 1002, as shown in Figure 10B. In some embodiments, the heat source may include a thermally conductive material 1008 between the motor assembly 1002 and the nacelle 1005.

[0135] Figure 11 illustrates an exemplary propeller system 1100 configured to manage icing on the surface of an electric aircraft, consistent with the disclosed embodiments. The propeller system 1100 may comprise part of an electric aircraft, for example, the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 1100 may comprise a propeller 1101, a motor assembly 1102 comprising, for example, a motor 1135, a gearbox 1136, and an inverter 1137, a heat exchanger 1103, an oil passage 1104 comprising first and second segments 1111 and 1112, a pump 1140, and a nacelle 1105 comprising an upper lip 1110 and a lower lip 1109, and configured to direct airflow 1107 into the heat exchanger 1103.

[0136] The components of propeller system 1100 may be similar to those of propeller systems 900A-900H, 1000A, or 1000B discussed above, with the reference number beginning with "11" instead of "10" or "9". For example, the oil passage 1104 in Figure 11 may be similar to the oil passage 1004 in Figures 10A-10B or the oil passage 904 in Figures 9A-9H. Therefore, the description of some components may be omitted here. In the embodiment of Figure 11, the heat exchanger 1103 may be located at the opening of the inlet 1106, such as the upper lip 1110 or the lower lip 1109, thereby directly heating the upper or lower lip by thermal contact with the heat exchanger 1103.

[0137] For example, the oil passage 1104 may be configured to thermally couple the heat exchanger 1103 to the motor assembly 1102. The oil passage 1104 may pass through the motor assembly 1102 and the heat exchanger 1103. The nacelle 1105 may include an air inlet 1106, and the heat exchanger 1103 may be positioned at the air inlet 1106.

[0138] In Figure 11, the heat exchanger 1103 may be positioned at an air inlet 1106 configured to passively prevent icing without requiring an additional oil flow segment. By positioning the heat exchanger 1103 directly at or near the inlet, icing can be prevented by heat conduction between the heat exchanger 1103 and the air inlet 1106.

[0139] In some embodiments as discussed above, the high acceleration of the propeller can be used to remove icing. In some embodiments, the propeller acceleration can be further used to determine the presence of icing conditions. Figure 12 illustrates an exemplary system 1200 for determining icing conditions on a propeller or other surface of an aircraft, consistent with the disclosed embodiments. For example, system 1200 may be used to determine an icing condition input, for example, as discussed with respect to Figures 2, 3, 5, or 6. System 1200 may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. System 1200 may comprise a propeller 1201, a gearbox 1202, a motor 1203, an inverter 1204, and one or more accelerometers. For example, the accelerometer may be located within a module of the motor assembly, such as within the gearbox 1202, the motor 1203, or the inverter 1204. Alternatively or additionally, accelerometers may be located on components of the propeller 1201 or at connections between modules. As schematically illustrated, accelerometers may be located outside or inside modules. Multiple accelerometers may be provided in a given module, for example, to monitor vibration or other motion conditions in multiple degrees of freedom.

[0140] The accelerometer 1210 may be configured, for example, to monitor vibrations or other motion conditions within the propulsion system. In some embodiments, multiple accelerometers 1210 may be provided in a given module to monitor these motion conditions in multiple degrees of freedom, such as orthogonal x, y, or z axes, or other degrees of freedom. In some embodiments, additional accelerometers may be provided for redundancy or to monitor torsional modes or other complex modes. Because icing can alter the mass distribution of rotating components such as propeller blades, hubs, or shafts, the vibration frequency profile 1211 may deviate from predicted values ​​for a given set of flight conditions. For example, the magnitude of vibration at a particular frequency value may include normal or predicted components 1213 (indicated by hatched bars) and additional aberration components 1214 (indicated by white or blank bars) that may indicate icing conditions. Because icing alters the mass distribution of rotating components such as propeller blades, hubs, or shafts, deviations from predicted values ​​may indicate icing conditions. In other words, deviations from the predicted amplitude of vibrations at a given frequency for a known set of flight conditions may indicate a change in mass distribution due to icing. In some embodiments, such deviations may be inferred to originate from a particular icing condition, for example, based on modeling to identify ice-related deviations, or based on meteorological data, flight conditions, or other factors that indicate that vibration deviations are likely to originate from an icing condition. In some embodiments, ice accumulation may attenuate certain frequencies or shift natural vibration modes to frequencies higher or lower than predicted values. Thus, in some embodiments, determining an icing condition may involve determining that the frequency is lower than predicted or that the natural mode is deviating from predicted values.

[0141] In some embodiments, the set of flight conditions being monitored may correspond to normal flight conditions. In some embodiments, flight conditions may be induced to probe for icing conditions. For example, propeller speed, torque, or other parameters may be modulated to create conditions in which icing can be more easily detected by generating more pronounced or recognizable vibrations or other disturbances.

[0142] Additionally, some electric engine designs may limit the available torque slew rate (i.e., the rate of change of engine torque over time), which may restrict the ability to use high propeller acceleration as a mechanism for measuring icing conditions or vibrations. For example, an electric aircraft engine may monitor propeller parameters using a flight control system that relies on quadratic estimation instead of direct measurement. Using such a system, the electric engine may not be able to operate at its maximum capacity because the estimator in the flight control system cannot accurately measure acceleration, velocity, torque, or other parameters. For example, an electric engine design may be limited to a slew rate of 3000 N-m / s or less at positive speeds of, for example, 50 rpm or more. While this may be acceptable for normal flight, it would be beneficial to allow the engine to perform acceleration outside the typical operating envelope, for example, for the purpose of measuring icing or monitoring the system's motion state for other reasons. Thus, in some embodiments, a motor position sensor may be used to perform the above measurements. An example of a motor position sensor is considered with respect to Figure 13 below.

[0143] Figure 13 illustrates an exemplary system 1300 for determining icing conditions on an aircraft propeller or other surface, consistent with the disclosed embodiments. The system 1300 may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. For example, the system 1300 may comprise a propeller 1301, a gearbox 1302, a motor 1303, an inverter 1304, and a motor position sensor 1305. The motor position sensor 1305 may be configured to directly measure angular position. For example, the motor position sensor 1305 may be configured, for example, on the propeller 1301, or on the output of the gearbox 1302 or motor 1303. In some embodiments, the motor position sensor 1305 may include, for example, a resolver. The motor position sensor 1305 may be configured to directly measure angular position with high accuracy and speed, for example, for greater feedback control of propeller speed and torque. Therefore, the addition of a motor position sensor can be used to achieve a higher torque-through rate at increased propeller speeds, which may be used to achieve a higher magnitude of the modulation parameter considered above in embodiments of the present disclosure.

[0144] Figure 14 illustrates an exemplary system for determining icing conditions on a propeller or other surface of an aircraft, consistent with the disclosed embodiments. System 1400 may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. For example, System 1400 may illustrate a control architecture using a motor position sensor, as discussed above with respect to Figure 13. System 1400 may comprise a motor control unit (MCU) 1401 having a motor control module 1402 and a position estimation module 1403, and a motor position sensor 1405. The motor position sensor 1405 may correspond, for example, to the motor position sensor 1305 in Figure 13. In some embodiments, the motor position sensor 1405 may include, for example, a resolver. The position estimation module 1403 may receive voltage phase information 1406 and current phase information 1407 from an electric engine, such as the inverter 1304 in Figure 13. In some embodiments, voltage phase information 1406 and current phase information 1407 may be generated from sensors on the phase connection of the inverter 1304 in Figure 13. A position estimation module 1403 may estimate the angular position of a propeller, such as the propeller 1301 in Figure 13. A motor control module 1402 may receive a position estimation signal from the position estimation module 1403 and a position measurement signal from the motor position sensor 1405. Based on the position estimation signal and the position measurement signal, the motor control module 1402 may output a pulse-width modulation (PWM) command 1408 to perform high-speed and accurate angular measurement of the propeller in a VTOL or other distributed propulsion aircraft.

[0145] In some embodiments, the oil path may flow through other ice-prone areas to serve the dual purpose of preventing ice formation and providing a secondary heat exchange surface. For example, a spinner or propeller blade may be configured to circulate hot oil to function as a primary or auxiliary heat exchanger while managing adhesion on their surfaces. In some embodiments, using such a surface as a primary heat exchanger may eliminate the need to provide a dedicated heat exchanger altogether. For example, the heat exchanger 1511 discussed below with respect to Figure 15 may be eliminated in some embodiments if, for example, the spinner 1501 provides a sufficient heat exchange surface.

[0146] Figure 15 illustrates an exemplary propeller system 1500 configured to manage icing on the spinner 1501, consistent with the disclosed embodiments. The propeller system 1500 may comprise part of an electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 1500 may comprise a spinner 1501, a propeller flange 1502, a propeller bearing 1503, multiple windings 1504, multiple magnets 1505, a gearbox 1506, a propeller shaft 1507, a motor feed 1508, an inverter feed 1509, a pump 1510, a heat exchanger 1511, a high-temperature oil path 1512, a low-temperature oil path 1513, a shaft oil path 1514, and a spinner oil path 1515. In this context, “spinner” may refer to a cap or other aerodynamic outer surface at the center of rotation of the propeller. The spinner 1501 can be mounted on the propeller shaft 1507 via the propeller flange 1502. A shaft oil path 1514 within the propeller shaft 1507 can be connected to the propeller flange 1502. The shaft oil path 1514 within the propeller shaft 1507 can travel along the propeller shaft 1507 toward the propeller flange 1502 and the spinner 1501.

[0147] The oil passages can be described starting from a sump 1516 that collects oil heated by various components of the propeller system 1500, such as windings 1504, magnets 1505, or gearbox 1506, or oil supplied by an inverter (not shown, inverter feed 1509). The heated oil can be pumped by a pump 1510 through a high-temperature oil passage 1512 into a heat exchanger 1511. The heat exchanger 1511 can cool the oil, for example, by exchanging heat with an airflow passing through it, and then reheat the oil by sending it back to various components through a cold oil passage 1513. The oil can travel along a shaft oil passage 1514 and be sent to a spinner 1501, for example, through a propeller flange 1502. For example, it can circulate through a spinner oil passage 1515. The spinner oil passage 1515 may include, for example, a conduit, microtube, or other path configured to distribute oil along its inner surface. For example, the spinner path may include channels similar to those used in heat exchangers and may be joined or brazed onto the spinner 1501, or may be integrally formed within the spinner 1501 shell. Hot oil may be circulated through the spinner oil path 1515, for example, by a pump 1510 or by the centrifugal force of a rotating propeller. For example, in some embodiments, the spinner oil path 1515 may be introduced into the radially inner portion of the spinner 1501 and returned to the more radially outer portion of the propeller flange 1502, providing net centrifugal force to the oil in the spinner oil path and assisting its circulation. Thus, the hot oil may enter through the central portion of the propeller flange 1502 and circulate through the oil path 1515 to exchange heat with a cold surface and melt or prevent ice buildup. The oil is then directed back to the propeller flange 1502, for example, by moving through the propeller bearing 1503, for example, to the windings 1504 or other high-temperature components, and can eventually be returned to the sump 1516 to repeat the oil flow cycle.

[0148] The de-icing path in spinner 1501 can cool the oil reaching sump 1516 to a lower temperature than would be possible without such a path. Therefore, the spinner oil path can reduce the cooling requirements of heat exchanger 1511, allowing for a smaller heat exchanger design or even eliminating the need for one entirely. Reducing or eliminating the heat exchanger can simultaneously reduce or eliminate the need for a corresponding air inlet, allowing for a significantly more streamlined propeller nacelle profile, reducing drag and increasing energy efficiency.

[0149] Figure 16 illustrates an exemplary system 1600 for managing icing on a spinner, consistent with the disclosed embodiments. System 1600 may comprise, for example, a subsystem of the propeller system 1500 in Figure 15. For example, system 1600 may comprise part of an electric aircraft, such as the VTOL aircraft 100 in Figures 1A and 1B. System 1600 may comprise a pump 1610, a stationary oil plenum 1611, a tail bearing 1612, a rotating oil plenum 1613, a propeller shaft 1607, a shaft oil path 1614, a propeller flange 1602, a stationary channel 1617, and a sealed bearing system 1618. Pump 1610 may pump oil into the stationary oil plenum 1611 through the stationary channel 1617, which may optionally pass through the tail bearing 1612 into the rotating oil plenum 1613. The rotating oil plenum 1613 may be configured to rotate relative to stationary components via a sealed bearing system 1618 so that it can move together with other rotating components of the propeller system, such as the propeller shaft 1607 or the propeller flange 1602. Oil may enter the shaft oil path 1614 via the rotating oil plenum 1613 and enter the spinner (not shown) via the shaft flange 1602. The rotating oil plenum 1613 and the stationary oil plenum 1611 may supply hot oil from the stationary components of a propeller electric engine to rotating components such as the spinner 1501 in Figure 15.

[0150] Figures 17A–17B illustrate an example of a propeller system 1700 configured to manage icing on a spinner or propeller blade, consistent with the disclosed embodiments. The propeller system 1700 may comprise, for example, a part of an electric aircraft such as the VTOL aircraft 100 in Figures 1A and 1B. The propeller system 1700 may comprise a spinner 1701, a spinner oil path 1715, a blade channel 1716, a heat conductor 1717, an oil path inlet 1718, an oil path outlet 1719, and a blade 1720.

[0151] The propeller system 1700 may be similar to system 1500 in Figure 15, with the addition of an ice management system within the blade 1720. For example, oil may be distributed from a spinner oil path (also called a spinner channel) 1715 to an internal blade channel 1716, which may be formed, for example, within the blade material or joined to a hollow interior. As can be seen at the top of Figure 17A, in some embodiments, the blade channel 1716 may extend along substantially the entire length of the blade 1720. For example, in some embodiments, the forces exerted on the oil due to the rotation of the propeller blade 1720 may be substantially equal in both the radially outward segment 1716a and the radially inward segment 1716b, and as a result, the opposing forces may essentially cancel each other out, for example, forces applied along the oil passage from a pump or other circulation mechanism and pressure losses along the oil path. Therefore, in some embodiments, it may be desirable for the internal blade channels 1716 to extend substantially along the entire length of the blade 1720 to prevent ice formation and generate an additional heat exchange surface. For example, if all the rotating spinners and blades function as heat exchangers, in some embodiments it may be possible to significantly reduce the size of the heat exchangers in the nacelle or eliminate them entirely to save cost and weight and reduce drag.

[0152] However, a further concern is the possibility of air being present in the oil circulating through the spinner oil path 1715 and the blade channel 1716. The further the radially outward-facing blade channel extends, the more the blade 1720 can act as a centrifuge for separating air from the oil. This can disrupt the fluid flow and create undesirable imbalances within the propeller blade. Therefore, in some embodiments, as can be seen at the bottom of Figure 17A, the blade channel 1716 may extend only through a portion of the blade, for example, 20%, 30%, 40%, 50%, 60%, or 70% of the blade radius measured from the axis of rotation. The specific radius selected may depend on the fluid flow characteristics, channel width, expected blade operating conditions, and the extent to which the oil can be degassed. In some embodiments, the remainder of the blade 1720 may be heated, for example, by providing a heat conductor 1717 from the blade channel 1716 to the radially outward-facing portion of the blade 1720.

[0153] Furthermore, it should be noted that the radial internal heating characteristics of the blade channel 1720 at the bottom of Figure 17A can be combined with the ice management cycles described above. For example, while the blade channel 1716 may be suitable for heating the radially inner portion of the blade 1720, some ice management cycles may be more effective for the radially outer portion. By providing the blade channel 1716 and performing an ice management cycle, such as adjusting the propeller speed, ice can be effectively managed along the entire length of the blade 1720. Similarly, providing the blade channel 1716 can reduce the required size of the management cycle, as it does not require, for example, a propeller RPM or tip Mach number to be high enough to remove ice from the radially inner portion, but instead can be designed only to manage ice on the outer portion of the blade 1720. Thus, the combination of a blade channel and an ice management cycle can provide excellent ice management.

[0154] As discussed above and further illustrated in Figure 17B, in some embodiments, the oil may circulate only through the blades 1720 and not necessarily through dedicated heat exchange channels within the spinner 1701. Instead, the oil flow may enter through one or more oil path inlets 1718 and be distributed to each blade channel 1716. After cycling through the blade channels, the circulating oil may be rejoined at one or more oil path outlets 1719. It may be desirable to concentrate the oil flow on the propeller blades 1720 to improve the performance of the oil flow system not only as an ice management system but also as a heat exchanger. For example, the surface of the spinner 1701 may be provided with a constant airflow in a cruising configuration, but this may not be the case when hovering or slowly ascending or descending. In such situations, only the rotating blades may continue to provide continuous contact with an airflow strong enough to perform heat exchange with the oil within the blades. Thus, in some embodiments, by concentrating the oil flow within the blade 1720, it is possible to reduce or eliminate dedicated air-oil heat exchangers (such as heat exchanger 803 in Figure 8A), which can also reduce or eliminate the need for drag-inducing features (such as air inlet 806 in Figure 8A). For example, when the propeller blade 1720 functions as the sole heat exchanger for the propeller assembly, it may be possible to eliminate the air inlet, as the sole heat exchanger is located outside the aircraft's skin 1722 (such as outside the nacelle, boom, or other external aerodynamic surface), eliminating the need to draw air into the aircraft. In some embodiments, multiple propeller blades 1720 may function as primary heat exchangers in the propeller system. The blades can be considered “primary” heat exchangers when, for example, a significant portion of the heat generated by the motor assembly is transferred to the external environment by heat conduction through the propeller blades. For example, a significant portion of the heat may include, for example, at least 30%, at least 50%, or at least 70% of the heat generated by the motor assembly.In some embodiments, for example, when other heat transfer components (e.g., cooling fins or air-oil heat exchangers) do not transfer more heat from the motor assembly to the external environment than the propeller blades, the blades may be considered a “primary” heat exchanger. Alternatively or additionally, when the propeller assembly does not have other components designed to function as a heat exchanger, the blades may be considered a “primary” heat exchanger.

[0155] Figures 18A–18K illustrate exemplary systems for managing icing on a propeller assembly, consistent with the disclosed embodiments. As will be discussed below, ice management systems according to embodiments of the present disclosure may utilize the electrical or mechanical power of the propeller to wirelessly generate heat within moving components of the propeller assembly, such as the propeller blades or spinner.

[0156] For example, in some embodiments, an array of magnets is placed in the stationary part of the propeller assembly. In this context, "stationary" may refer to aircraft components that do not rotate with the propeller blades, such as the motor assembly, boom, nacelle, etc. In some embodiments, the magnets may include permanent magnets. In some embodiments, the magnets may include electromagnets coupled to an AC or DC power circuit.

[0157] Magnets may be positioned in close proximity to conductive parts on the moving parts of the propeller assembly. In some embodiments, the conductive parts may include conductive strips configured to generate eddy currents as the material moves through a magnetic field generated by the array of magnets. The eddy currents may be conducted to other parts of the propeller assembly by further electrical or conductive materials, such as wiring embedded in the blades, spinner, or other ice-prone surfaces. In some embodiments, the conductive parts may include windings. Magnets may be configured to induce an electric current within the windings. The current may then flow to other parts of the blades and spinner, for example, by embedded wiring, which may generate heat at desired locations by resistance heating to manage ice formation.

[0158] Various embodiments for electric ice management are discussed below. It should be understood that, as is true in the embodiments shown in Figures 1-17B above, the features listed in each of Figures 18A-18K can be used in combination with each other, and furthermore, features from one illustrated embodiment can be incorporated into or substituted for another embodiment of the illustrated embodiment. For example, the coil illustrated in Figure 18J can be used in addition to, or instead of, the permanent magnet illustrated in Figure 18G.

[0159] Furthermore, although Figures 18A–18K illustrate tilt propellers, embodiments of the present disclosure are not limited thereto. For example, the features described below may be implemented, for example, on lift propellers or other types of aircraft propeller assemblies.

[0160] As can be seen in Figure 18A, the propeller assembly 1800 may include, for example, a motor assembly 1802 configured to rotate the propeller shaft 1814, a propeller hub 1818 coupled to the propeller shaft 1814 by a propeller flange 1816, a spinner 1801, and propeller blades 1820.

[0161] The propeller assembly 1800 may include a spinner rod 1832 inside the spinner 1801. The spinner rod 1832 may extend, for example, from the propeller hub 1818 and may be coaxial with the axis of rotation of the propeller shaft 1814. The spinner rod may be fixed to the propeller hub 1818 and may be configured to rotate with the propeller hub 1818 and other rotating elements of the propeller assembly 1800. In some embodiments, the spinner rod may include, or be fixed to, another rotating element of the propeller assembly, such as the propeller flange 1816, the spinner 1801, or other mechanisms within the spinner 1801, such as a pitch control rod or a yoke plate (not shown). As shown, the spinner rod 1832 is cantilevered from the propeller hub 1818, but embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the spinner rod 1832 may instead be cantilevered from the spinner 1801, or the propeller hub 1818 may be connected to the spinner 1801. While a spinner rod 1832 connecting the propeller hub 1818 to the spinner 1801 may provide greater stability and durability of the propeller structure, cantilevered spinner rods may be preferred in some embodiments, given their compact and lightweight design.

[0162] The magnet 1830 may be suspended from the spinner rod 1832 by a bearing 1833 and an arm 1836. For example, the magnet 1830 may include one or more permanent magnets. The bearing 1833 may isolate the magnet 1830 from the rotational motion of the propeller assembly, so that in the horizontal thrust direction shown in the figure, the magnet 1830 remains suspended downward by gravity while the spinner rod 1832 rotates with the propeller. In a completely vertical thrust direction, the magnet 1830 may also remain sufficiently isolated from the rotation of the propeller assembly by inertia, so that ice management may be effective in both climb and cruising configurations. However, it should be noted that tilt propellers are often oriented at a slight angle to the vertical, even during takeoff, landing, and hovering, so that gravity may nevertheless help to keep the magnet 1830 stationary.

[0163] The spinner 1801 may include a conductive portion 1831 located in close proximity to the magnet 1830. In some embodiments, as shown in Figure 18A, the conductive portion 1831 may include a metal sheet 1831a, such as aluminum, copper, iron, or steel (e.g., carbon steel, electric steel, stainless steel, etc.). The conductive portion 1831 may be attached to the inner surface of the spinner 1801 or embedded within the spinner 1801. The conductive portion may be located on the side of the spinner, as can be seen in Figure 18A. For example, the side of the spinner may refer to the portion of the spinner 1801 that is more radially outward toward the propeller blade 1820 than toward the forward flight direction. In some embodiments, the metal sheet may be continuously wrapped around the inner surface of the spinner, as shown in the upper left corner of Figure 18A (the conductive portion 1831a is illustrated in a "spread out" form as a continuous strip spanning a complete circular path of 0–2π). In some embodiments, as discussed below, multiple magnetic field sensors 1835 may be arranged alongside the conductive portion 1831.

[0164] When the propeller is operating, the relative motion between the suspended magnet 1830 and the spinner 1801 can generate eddy currents within the conductive portion 1831, causing heat to be generated in the conductive portion 1831. This heat can then warm the spinner to manage ice formation. In some embodiments, the generated heat can be distributed by a wiring path 1817. The wiring path 1817 may include a system of thermally conductive materials such as carbon fiber, metal wire, or mesh, and may be configured to distribute eddy current heat by conduction to ice-prone surfaces of the propeller assembly, such as the spinner 1801, blades 1820, or other locations.

[0165] The embodiment of the icing management system shown in Figure 18A provides a simple, passive, fail-safe design that does not require any dedicated control components to operate. This "always-on" design can also reduce the burden of ice detection. For example, it may never be important to know the status of icing on the aircraft's surface, but it may not be necessary to specifically determine when ice management should be initiated.

[0166] In some embodiments, an array of magnetic field sensors 1835 may be located near the conductive portion 1831. The magnetic field sensors 1835 may be configured to detect the magnetic flux of the magnet 1830 as it passes through during the rotation of the propeller. This sensor data may be transmitted, for example, to the inverter or control circuit of the motor assembly 1802, which is used as a rotational position sensor. For example, the sensor data may be transmitted to the stationary portion of the propeller assembly via, for example, wireless transmission, slip rings, etc. In this way, it may be possible to integrate the rotational position sensor into the structure of the icing management system and reduce the number of separate dedicated sensors and control circuits within the propeller assembly 1800.

[0167] In addition to alternative or eddy current heating, in some embodiments ice management can be achieved by generating and driving a current throughout the spinner 1801 or blade 1820. For example, as schematically shown in the upper left corner of Figure 18B, the conductive portion 1831 may include multiple windings 1831b. When the propeller is operating, the relative motion between the suspended magnet 1830 and the spinner 1801 can induce a current in the windings 1831b of the conductive portion 1831, which can be distributed by a wiring path 1817. For example, the wiring path 1817 may include a conductive portion such as a metal wire that can distribute the current throughout the spinner 1801 or blade 1820 and manage ice on their surfaces by resistive heating. In some embodiments, resistive heating can be controlled at desired locations by adjusting the thickness or other structural properties of the wiring path 1817. For example, if it is desirable to generate more heat at the tip of blade 1820 than at their base, the segments of the wiring path 1817 can be made thinner at the blade tip to increase resistive heating at those locations.

[0168] In some embodiments, the switch 1834 may be configured to selectively enable or disable electrical contact between the wiring path 1817 and the conductive part 1831. For example, in some embodiments, the switch 1834 may include a thermostat switch configured to disable electrical contact when the temperature at the switch 1834 exceeds a predetermined threshold. Alternatively or additionally, the switch 1834 may include an actively controlled switch that can be operated, for example, by a pilot or a flight control system. For example, in some embodiments, the switch 1834 may be configured to communicate wirelessly or via slip ring with a control circuit on a stationary part of the aircraft. In some embodiments, the switch 1834 may be battery-powered or driven or charged by a current induced in the winding 1831b of the conductive part 1831. By providing the switch 1834, it may be possible to disconnect the wiring path 1817 when ice management is not required to reduce energy loss, while still maintaining minimal complexity in the ice management control architecture.

[0169] In some embodiments, the switch 1834 may be designed with a default "on" setting, i.e., the switch may be configured to connect the wiring path 1817 and the conductive part 1831 by default, and to disable this connection when the switch is activated. In this way, a failure of the switch or its control architecture is more likely to result in an "always on" mode and less likely to disable the ice management function. Such a failure may be detected by determining that heating is activated when it should not be heated, which can be determined by the efficiency loss in the propeller assembly resulting from the heat generation.

[0170] In some embodiments, multiple switches may be provided to selectively enable or disable heating across different zones of the propeller assembly. For example, the different zones may include, for instance, the area of ​​the spinner 1801 or the spinner 1801, the area of ​​the individual blades 1820 or the area of ​​the individual blades 1820, or all of the blades 1820. By targeting different zones, it may be possible to selectively concentrate heating power where needed, depending on the icing conditions.

[0171] Figures 18C and 18D schematically illustrate additional configurations for ice management consistent with embodiments of the present disclosure. For example, embodiments according to Figures 18C and 18D may be similar to those described with respect to Figures 18A and 18B, except as described below.

[0172] As shown in Figure 18C, the magnet 1830 may be oriented towards the front of the spinner 1801, and the conductive portion 1831 (e.g., a metal sheet 1831a as shown in Figure 18A or multiple windings 1831b as shown in Figure 18B) may be located at the front. In this context, the “front” of the spinner may refer to the direction of thrust of the spinner. For example, in the case of a tilt propeller, when the propeller is in a horizontal thrust configuration or a cruising configuration, the front may correspond to the forward flight direction. A forward-facing arrangement may be advantageous in that it places the conductive portion closer to areas of the spinner 1801 that are likely to have more ice. Additionally, in some embodiments, a forward-facing arrangement may better accommodate spatial requirements by positioning the magnet 1830, spinner rod 1832, and bearing 1833 away from other components, such as a pitch control mechanism (not shown).

[0173] Alternatively or additionally, as shown in Figure 18D, the magnet 1830 may be oriented away from the front of the spinner 1801, such as toward the propeller hub 1818 or the propeller flange 1816. The conductive portion 1831 may also be mounted on or embedded in the propeller hub 1818 or the propeller flange 1818. For example, an exemplary front view of the propeller hub 1818 is shown in the lower left of Figure 18D, where the conductive portion 1831 includes a flat disk or washer-shaped conductive sheet 1831a configured to generate eddy current heating as discussed above. Alternatively or additionally, as shown in the upper left corner of Figure 18D, the conductive portion 1831 may include a plurality of windings 1831b arranged in a circular pattern within the plane of the propeller hub 1818 and configured to generate and drive current through the wiring path 1817.

[0174] In some embodiments, the magnets 1830 and conductive portion 1831 may be integrated, for example, into a bearing 1833 and a spinner rod 1832. For example, as shown in Figure 18E, the bearing 1833 ( schematically illustrated in the upper left corner of Figure 18E as a sleeve surrounding three rollers) may include multiple magnets 1830 arranged around its inner surface, facing multiple windings 1831b as a conductive portion 1831. The multiple windings may be arranged on or within the spinner rod 1832. While the spinner rod 1832 rotates, a counterweight 1837 may be suspended from the arm 1836 to maintain the bearing 1833 and magnets 1830 in a stationary orientation relative to gravity. For example, the bearing 1833 may include rollers 1850 between an inner bearing surface 1851 (e.g., on the outside of the rod 1832) and an outer bearing surface 1852 (e.g., on the internal sleeve of the bearing 1833). Thus, the current is induced within the winding and can be distributed throughout the spinner 1801 or blade 1820 by the wiring path 1817. In some embodiments, the length of the arm 1836 can be optimized to increase the gravity-induced torque on the bearing 1833 and maintain it in a desired orientation. In some embodiments, as can be seen in the lower left corner of Figure 18E, the arm 1836 can be eliminated, and the counterweight 1837 can be integrated into the housing of the bearing 1833 to create a mass imbalance that maintains the bearing 1833 and keeps it in a desired orientation. The configuration in Figure 18E can enable compact and efficient power generation without requiring a control architecture or electrical connection to the stationary part of the propeller assembly 1800.

[0175] In some embodiments, as shown in Figure 18F, the spinner rod 1832 may be fixed to the propeller assembly or a stationary part of the aircraft such that there is relative rotation between the spinner rod 1832 and the spinner 1801. For example, the spinner rod 1832 may include a pitch control rod passing through the propeller shaft 1814. The pitch control rod 1832 may remain stationary with respect to the rotational direction around the axis of the propeller shaft 1814 and may be able to translate linearly along the propeller axis (as indicated by the bidirectional arrows) to actuate pitch control components such as a yoke or link 1845 and a blade actuation pin 1846. For example, the pitch control rod 1832 may be translated linearly by a pitch actuator 1847 on the propeller system or a stationary part of the aircraft. The yoke 1845 and blade actuation pin 1846 may rotate together with the other rotating parts of the propeller system, but the pitch control rod 1832 may be rotationally isolated from the yoke 1845 by a bearing 1833, which may include, for example, a thrust bearing.

[0176] The magnet 1830 can be attached to the pitch control rod 1832 by the arm 1836 in a manner similar to that considered above. However, in the embodiment of Figure 18F, the arm can be rigidly coupled to the pitch control rod 1832. Thus, in the configuration of Figure 18F, the magnet 1830 and the arm 1836 do not need gravity to remain fixed while the conductive part 1831 rotates around it. Therefore, it may be possible to ensure a more stable configuration and may allow additional arms 1836 and magnets 1830 to be arranged symmetrically around the spinner rod 1832. For example, a second magnet 1830 at the top of Figure 18F may be positioned diametrically opposite to the first magnet 1830 shown at the bottom. In some embodiments, further magnets 1830 may be arranged around the spinner rod 1830, for example, three, four, five, six, or any preferred number. This may not only increase the generation of heat or electricity but also provide a simpler balancing of the propeller system.

[0177] In some embodiments, to reduce the effects of linear axial displacement that may occur between the magnet 1830 and the conductive portion 1831 during pitch control, at least one of the magnet 1830 or the conductive portion 1831 may be sized or positioned so that the magnet 1830 and the conductive portion 1831 are always sufficiently close to each other over the entire range of allowable blade pitch angles. In some embodiments, the sizing or positioning of the magnet 1830 and the conductive portion 1831 may be optimized for the primary pitch angle, or range of pitch angles, that is expected to be used in the cruising direction, while ice management may be most critical. In some embodiments, the arm 1836 and the magnet 1831 may be linearly separated from the pitch control rod 1832, for example, by a spline system (not shown), in order to maintain the proximity of the magnet 1830 to the conductive portion 1831. In such cases, for example, the magnet 1831 may be axially constrained by a groove or track 1848 coupled to a rotating part of a propeller assembly, such as a spinner 1801 or a propeller hub 1818. The groove or track 1848 may allow the magnet 1830 to maintain relative rotational motion with respect to the conductive portion 1831, for example, by bearings or other low-friction guides (not shown).

[0178] In some embodiments, the magnets 1830 may be mounted on the propeller assembly or a stationary part of the aircraft. For example, as shown in Figure 18G, multiple magnets 1830 may be mounted on the motor assembly 1802 and the surrounding propeller shaft 1814. For example, the magnets 1830 may be mounted directly on the outer surface of the motor assembly 1802, or they may be spaced apart from the motor assembly 1802 on an extension such as a cylindrical mount 1838. The cylindrical mount 1838 can further distance the magnets 1830 from the motor assembly 1802 and bring them closer to the windings 1831b of the conductive portion 1831. This can achieve improved efficiency of current generation in terms of reducing the gap between the magnets and the windings. It can also prevent overheating and demagnetization of the magnets 1830 by reducing thermal contact with the motor assembly 1802. Alternatively or additionally, the magnets 1830 may be mounted on other stationary components such as booms, nacelles, motor mounts, etc. The conductive portion may, for example, be mounted on the propeller hub 1818 and may include a plurality of windings surrounding the propeller flange 1816. Alternatively or additionally, the conductive portion may be mounted on another moving part of the propeller, such as the propeller flange 1816 or the propeller shaft 1814. Furthermore, although the conductive portion 1831 is illustrated as including a plurality of windings 1831b as described above, embodiments of the present disclosure are not limited thereto. For example, the conductive portion 1831 may include a metal sheet 1831a configured to generate eddy current heating as shown in Figure 18D.

[0179] For example, the upper left of Figure 18G illustrates the motor assembly 1802 as viewed from the propeller flange 1816 side along the axis of the propeller shaft 1814. The magnet 1830 and magnetic field sensor 1835 may be positioned around opposing surfaces of the motor assembly 1802 or another stationary component, as discussed above. The lower left of Figure 18G illustrates the propeller flange 1818 as viewed from the motor assembly 1802 side along the axis of the propeller shaft 1814. The winding 1831b and auxiliary magnet 1839 may be positioned around opposing surfaces of the propeller flange 1818 or another rotating component, as discussed above. The auxiliary magnet may be configured to provide a reference magnetic field for the magnetic field sensor 1835 to detect, allowing the magnetic field sensor to be positioned on the stationary side of the propeller system 1800. This may enable direct rotational position detection without the need to transmit power or signals wirelessly.

[0180] In some embodiments, the magnet 1830 may be positioned to face a conductive portion 1831 located on or within another rotating part of the propeller assembly 1800, for example, on or within the blade 1820. For example, as can be seen in Figures 18H and 18I, the conductive portion 1831 may be located, for example, on the trailing edge of the blade 1820 and positioned to face the magnet 1830. In some embodiments, the magnet 1830 may be mounted at an angle from the mounting surface to accommodate the contour of the blade 1820. For example, as can be seen in Figure 18H, the conductive portion 1831 may include, for example, a winding 1831b configured to drive current through a wiring path 1817. By embedding the winding directly into the propeller blade 1820, it may be possible to distribute heat more efficiently to each blade. Simultaneously, ice management for spinner 1801 can be achieved by routing the wiring path 1817 through the spinner, or by independently heating spinner 1801 using another of the disclosed techniques.

[0181] Alternatively or additionally, as can be seen in Figure 18I, the conductive portion may include a metal sheet 1831a that extends along the length of the blade 1820 and is configured to generate eddy current heating within the blade 1820. The heat can then be distributed to other parts of the blade 1820 or the spinner 1801 via the wiring path 1817. In some embodiments, the conductive portion 1831 may perform multiple functions on the blade 1820. For example, the conductive portion may form part of the blade spar or other structural support frame. As illustrated in Figure 18I, the conductive portion may include part of a lightning grounding path from the propeller to the aircraft frame. By designing the conductive portion to perform multiple required functions, it may be possible to simplify the propeller design while reducing weight and the number of components.

[0182] Furthermore, while the magnet 1830 in the exemplary embodiments shown in Figures 18A to 18I has been described in relation to a permanent magnet, the embodiments of this disclosure are not limited thereto. In some embodiments, the magnet 1830 in the above-described configuration may include an electromagnet. For example, Figures 18J and 18K schematically illustrate exemplary embodiments in which the magnet 1830 includes an electromagnet. Exemplary configurations may correspond, for example, to the configuration shown in Figure 18G. In some embodiments, the electromagnet may include a coil, such as an air core or iron core coil, connected to a power source. The power source may include, for example, a part of the motor assembly 1802, such as an inverter or a sub-control module (not shown).

[0183] In some embodiments, the coil may be connected to a DC power supply circuit 1840, as shown in Figure 18J. For example, in some embodiments, the DC power supply circuit may include a step-down converter circuit. The DC power supply circuit 1840 may approximate the magnetic field of a stationary permanent magnet. However, unlike the permanent magnet described above, the electromagnet 1830 can operate selectively only when needed, otherwise allowing the propeller to operate at optimal efficiency. Also, the magnitude of the magnetic field may be adjustable to generate a desired amount of heat.

[0184] However, a drawback of both the permanent magnets and DC-driven electromagnets discussed above is that both may require relative motion between the magnet 1830 and the conductive part 1831 in order to generate eddy current heating or to drive current through the wiring path 1817. Therefore, in some embodiments, as can be seen in Figure 18K, the electromagnet 1830 may include a coil connected to an AC power circuit 1841. In some embodiments, the conductive part 1831 may include a similar induction coil as illustrated, or may include a winding or metal sheet as discussed earlier. Since the AC power circuit generates a changing magnetic field, it may be possible to generate eddy current heating or induce current even when the propeller is stationary. This may be advantageous, for example, for de-icing when the aircraft is grounded. This may be particularly advantageous for use in lift propellers that can be stowed without moving during cruising flight in icing conditions. The AC power circuit 1841 may be configured to modulate both the amplitude and frequency of the magnetic field to adjust heating and current parameters.

[0185] A non-temporary computer-readable medium may be provided for storing instructions to one or more processors of a controller for performing embodiments of ice management of the present disclosure. For example, instructions stored on the non-temporary computer-readable medium may be executed by the controller's circuitry for partially or entirely performing any of the ice management processes disclosed above. Common forms of non-temporary media include, for example, floppy disks, flexible disks, hard disks, solid-state drives, magnetic tapes, or any other magnetic data storage media, compact disk read-only memory (CD-ROM), any other optical data storage media, any physical medium having a pattern of holes, random access memory (RAM), programmable read-only memory (PROM), and erasable programmable read-only memory (EPROM), FLASH-EPROM or any other flash memory, non-volatile random access memory (NVRAM), caches, registers, any other memory chips or cartridges, and networked versions thereof. One or more processors may include any combination of any number of central processing units ("CPUs"), graphics processing units ("GPUs"), neural processing units ("NPUs"), microcontroller units ("MCUs"), optical processors, programmable logic controllers, microcontrollers, microprocessors, digital signal processors, intellectual property (IP) cores, programmable logic arrays (PLAs), programmable array logic (PALs), generic array logic (GALs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), systems on a chip (SoCs), application-specific integrated circuits (ASICs), and so on. In some embodiments, one or more processors may be a set of processors grouped as a single logic component.

[0186] Embodiments of this disclosure may be further described with respect to the following provisions. 1. A flight control system for an aircraft, Memory for storing instructions, A processor configured to perform an operation by executing the aforementioned instructions, wherein the operation is The icing status is determined based on the input of the icing status, Determining the state of the aircraft based on one or more predefined flight parameters, Based on the icing conditions and aircraft status, the propeller modulation parameters are determined, A flight control system comprising generating a plurality of effector commands corresponding to the propeller modulation parameters, wherein the plurality of effector commands are configured to induce a first ice management cycle in a first symmetric pair of the aircraft's propellers and a second ice management cycle in a second symmetric pair of the aircraft's propellers, the first ice management cycle occurring at a first time interval different from the second time interval of the second ice management cycle. 2. The flight control system according to Clause 1, wherein the icing condition input is based on a primary ice detector. 3. A flight control system as described in Clause 1 or 2, in which the icing condition input is based on input from the flight control system or the pilot. 4. A flight control system as described in any of clauses 1 to 3, wherein one or more of the predefined parameters include one of the following: control margin status, current bank angle, load factor, vertical airspeed versus commanded airspeed, altitude, propulsion system, signal integrity, or flight mode. 5. A flight control system according to any one of clauses 1 to 4, wherein the propeller modulation parameter includes modulating one of the following: revolutions per minute (RPM), blade pitch angle, torque, or propeller tilt angle. 6. The flight control system according to any one of the clauses 1 to 5, wherein the propeller modulation parameter includes RPM, and the first ice management cycle includes increasing the RPM of a first symmetrical pair of propellers by at least 50 percent during the first time interval. 7. The flight control system according to any one of the clauses 1 to 5, wherein the propeller modulation parameter includes RPM, and the first ice management cycle includes increasing the RPM of a first symmetrical pair of propellers to at least 80 percent of the maximum RPM during the first time interval. 8. The flight control system according to any one of clauses 1 to 5, wherein the propeller modulation parameter includes a blade pitch angle, and the first ice management cycle includes changing the blade pitch angle of a first symmetrical pair of propellers by at least 5 degrees during the first time interval. 9. The flight control system according to Clause 8, wherein the first ice management cycle further includes changing the blade pitch angle of the first symmetrical pair of propellers by at least 5 degrees at least four times during the first time interval. 10. The flight control system according to any one of the clauses 1 to 9, wherein the propeller modulation parameter includes torque, and the first ice management cycle includes changing the torque of a first symmetrical pair of propellers by at least 50 percent during the first time interval. 11. The propeller modulation parameters include torque, and the first ice management cycle is A flight control system according to any one of clauses 1 to 9, comprising increasing the torque of a first symmetrical pair of propellers from an initial torque value to within 80 percent of the maximum torque, and decreasing the torque of the first symmetrical pair of propellers to the initial torque, during a first time interval. 12. The flight control system according to any one of the clauses 1 to 11, wherein the propeller modulation parameter includes a propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of a first symmetrical pair of propellers by at least 10 degrees during the first time interval. 13. A flight control system according to any one of clauses 1-5 or 8-12, wherein the propeller modulation parameter includes RPM, and the first ice management cycle includes increasing the first RPM of the first symmetric pair of propellers to at least 80 percent of the second RPM of the second symmetric pair of propellers during the first time interval. 14. The flight control system according to Clause 13, further comprising the first ice management cycle reducing the second RPM of the second symmetric pair of propellers during the first time interval to compensate for the increased RPM of the first symmetric pair of propellers. 15. The flight control system according to Clause 13 or 14, wherein the second ice management cycle includes increasing the second RPM of the second symmetric pair of propellers to at least 80 percent of the first RPM of the first symmetric pair of propellers during the second time interval. 16. The flight control system according to any one of the clauses 13 to 15, further comprising the second ice management cycle reducing the first RPM of the first symmetric pair of propellers during the second time interval to compensate for the increased RPM of the second symmetric pair of propellers. 17. A flight control system according to any one of clauses 1-7 or 10-16, wherein the propeller modulation parameter includes a blade pitch angle, and the first ice management cycle includes changing the first blade pitch angle of a first symmetrical pair of propellers by at least 5 degrees relative to the second blade pitch angle of a second symmetrical pair of propellers during the first time interval. 18. The flight control system according to Clause 17, wherein the first ice management cycle further comprises increasing the second RPM of the second symmetrical pair of propellers during the first time interval. 19. The flight control system according to Clause 17 or 18, wherein the second ice management cycle includes changing the second blade pitch angle of the second symmetrical pair of propellers by at least 5 degrees relative to the first blade pitch angle of the first symmetrical pair of propellers during the second time interval. 20. A flight control system according to any one of clauses 1-9 or 12-19, wherein the propeller modulation parameter includes torque, and the first ice management cycle includes increasing the torque of a first symmetrical pair of propellers from an initial torque value to a first torque value, and decreasing the torque of the first symmetrical pair of propellers from the first torque value to a second torque value. 21. The flight control system according to Clause 20, wherein the first torque value is within 80 percent of the maximum torque value of the first symmetrical pair of propellers. 22. The flight control system according to Clause 20 or 21, wherein the second torque value of the first symmetrical pair of propellers is less than 50 percent of the initial torque value. 23. The flight control system according to any one of the clauses 20 to 22, wherein the first ice management cycle further comprises increasing the second RPM of the second symmetrical pair of propellers during the first time interval. 24. A flight control system according to any one of clauses 1 to 23, wherein the propeller modulation parameter includes a propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of a first symmetrical pair of propellers by at least 10 degrees. 25. The flight control system according to Clause 24, wherein the first ice management cycle further comprises increasing the second RPM of the second symmetrical pair of propellers during the first time interval. 26. A flight control system according to any one of the clauses 1 to 25, wherein the first symmetrical pair of propellers includes a first outermost propeller from a first side of the aircraft body and a second outermost propeller from a second side of the aircraft body. 27. The flight control system according to Clause 26, wherein the second symmetrical pair of propellers includes a third propeller inside the first propeller located on the first side of the body of the aircraft, and a fourth propeller inside the second propeller located on the second side of the body of the aircraft. 28. The flight control system according to Clause 27, wherein the plurality of effector commands are further configured to induce a third ice management cycle in a third symmetrical pair of the aircraft's propellers, the third ice management cycle occurring in a third time interval, the third time interval being different from the first time interval and the second time interval. 29. The flight control system according to Clause 28, wherein the third symmetrical pair of propellers includes a fifth propeller between the first propeller and the third propeller on the first side of the body of the aircraft, and a sixth propeller between the second propeller and the fourth propeller on the second side of the body of the aircraft. 30. The flight control system according to any one of clauses 1 to 29, wherein the flight control system is configured to generate a plurality of effector commands at repeating time intervals. 31. The flight control system according to any one of the clauses 1 to 30, wherein the plurality of effector commands are configured to trigger the first ice management cycle and the second ice management cycle at non-overlapping time intervals. 32. A flight control system according to any one of the clauses 1 to 31, wherein the first symmetrical pair of propellers and the second symmetrical pair of propellers include a pair of tilt propellers. 33. The first ice management cycle is A flight control system according to any one of the clauses 1 to 32, further comprising rotating a symmetrical pair of lift propellers between a first angular position and a second angular position, wherein the first angular position is offset from the second angular position by a multiple of 30 degrees. 34. The flight control system according to Clause 33, wherein each lift propeller of a symmetrical pair of lift propellers is positioned behind the corresponding tilt propeller of the first symmetrical pair of tilt propellers in the forward flight direction. 35. The flight control system according to Clause 33 or 34, wherein each lift propeller of the symmetrical pair of lift propellers is located further from the aircraft body than the corresponding tilt propeller of the first symmetrical pair of tilt propellers. 36. A flight control system according to any one of the clauses 32 to 35, wherein each lift propeller of the symmetrical pair of lift propellers is positioned closer to the aircraft body than the corresponding tilt propeller of the first symmetrical pair of tilt propellers. 37. A flight control system according to any one of the clauses 1 to 31, wherein the first symmetrical pair of propellers and the second symmetrical pair of propellers include a pair of lift propellers. 38. The flight control system according to Clause 37, wherein the first ice management cycle includes rotating a first symmetrical pair of propellers between a first angular position and a second angular position, the first angular position being offset from the second angular position by a multiple of 30 degrees. 39. The flight control system according to Clause 38, wherein rotating the first symmetrical pair of propellers includes rotating the first lift propeller of the first symmetrical pair of propellers in the opposite direction to the second lift propeller of the first symmetrical pair of propellers. 40. The flight control system according to any one of the clauses 1 to 39, wherein the plurality of effector commands are configured to perform the first ice management cycle at periodic intervals based on a predetermined schedule in order to manage asymmetric icing. 41. A flight control system according to any one of the clauses 1 to 40, wherein the flight control system is configured to generate the plurality of effector commands at periodic intervals in order to manage asymmetric icing. 42. A propeller assembly for an aircraft, Propeller and, A motor assembly coupled to the propeller, Heat exchanger, An oil passage configured to thermally couple a heat exchanger to a motor assembly, comprising an oil passage including a first segment, a second segment, and a third segment, A nacelle mechanically coupled to the motor assembly, the nacelle includes an air inlet configured to direct air to the heat exchanger, the air inlet includes a lower lip relative to the forward flight configuration and an upper lip opposite to the lower lip, the lower lip being further from the motor assembly than the upper lip, The first segment passes through the motor assembly, The second segment passes through the heat exchanger, The third segment passes along the lower lip, The oil passage bypasses the upper lip. Propeller assembly. 43. The propeller assembly according to Clause 42, further comprising a thermally conductive material between the motor assembly and the upper lip, configured to conduct heat from the motor assembly to the upper lip. 44. The nacelle comprises the first material, The thermally conductive material includes a second material different from the first material, The second material has a higher thermal conductivity than the first material. The propeller assembly described in Clause 43. 45. The propeller assembly according to clause 43 or 44, wherein the thermal conductive material extends along the two sides of the air inlet between the upper lip and the lower lip. 46. ​​A propeller assembly according to any one of the clauses 43 to 45, wherein the thermally conductive material extends from the inside of the motor assembly to the outside of the motor assembly. 47. The propeller assembly according to Clause 46, wherein the thermal conductive material includes a plate extending from the inside of the motor assembly to the outside of the motor assembly. 48. A propeller assembly according to any one of the clauses 43 to 47, wherein the thermally conductive material encloses the motor assembly. 49. The propeller assembly according to any one of the clauses 42 to 48, wherein the third segment branches off from the second segment in the oil flow direction and returns to the second segment in the oil flow direction. 50. The propeller assembly according to Clause 49, wherein the first segment flows into the second segment in the direction of the oil flow and returns from the second segment in the direction of the oil flow. 51. A propeller assembly according to any one of the clauses 42 to 50, further comprising a first flow control valve configured to regulate the flow rate of oil through the third segment. 52. The propeller assembly according to Clause 51, wherein the first flow control valve is configured to selectively block the oil flow to or from the third segment. 53. The propeller assembly according to clause 51 or 52, further comprising a second flow control valve, wherein the first flow control valve is located on the inlet side of the third segment and the second flow control valve is located on the outlet side of the third segment. 54. The propeller assembly according to any of the clauses 42 to 53, wherein the third segment extends along the lower surface of the nacelle with respect to the forward flight configuration. 55. The propeller assembly according to any one of the clauses 42 to 54, wherein the third segment branches off from the first segment in the oil flow direction at the outlet point of the first segment. 56. The propeller assembly according to Clause 55, wherein the third segment flows into the second segment in the direction of the oil flow. 57. The propeller assembly according to Clause 55 or 56, wherein the third segment returns to the first segment in the oil flow direction at the inlet point of the first segment, and the inlet point of the first segment is downstream of the outlet point of the first segment in the oil flow direction. 58. The propeller assembly according to Clause 57, wherein the inlet point of the first segment is located upstream of the second segment in the direction of oil flow. 59. The propeller assembly according to Clause 57, wherein the inlet point of the first segment is located downstream of the second segment in the direction of oil flow. 60. A propeller assembly according to any of the clauses 42 to 59, wherein the third segment is connected in series within the first segment. 61. A propeller assembly according to any of the clauses 42 to 60, wherein a first portion of the first segment flows into the third segment, and the third segment flows into the second portion of the first segment. 62. A propeller assembly according to any of clauses 42 to 61, wherein a first portion of the first segment flows into the third segment, and the third segment flows into the second portion of the first segment. 63. A vertical takeoff and landing aircraft having a propeller assembly as described in any of clauses 42 to 62, The propeller, motor assembly, heat exchanger, and nacelle are configured to tilt between an ascent configuration and a cruising configuration relative to the frame of the vertical takeoff and landing aircraft. Vertical takeoff and landing aircraft. 64. A propeller assembly for an aircraft, Propeller and, A motor assembly coupled to the propeller, Heat exchanger, An oil passage configured to thermally couple the heat exchanger to the motor assembly, comprising an oil passage including a first segment and a second segment, A nacelle mechanically coupled to the motor assembly, the nacelle including an air inlet configured to direct air to the heat exchanger, the air inlet including a lower lip relative to the forward flight configuration and an upper lip opposite to the lower lip, the lower lip being further from the motor assembly than the upper lip, A heat pipe circuit configured to collect heat from a heat source and discharge the heat to the lower lip, Equipped with, The first segment passes through the motor assembly, and the second segment passes through the heat exchanger. Propeller assembly. 65. The propeller assembly according to Clause 64, wherein the heat source includes the motor assembly. 66. The propeller assembly according to clause 64 or 65, wherein the heat source includes a thermally conductive material between the motor assembly and the nacelle. 67. A propeller assembly according to any one of the clauses 64 to 66, wherein the heat source includes the heat exchanger. 68. A propeller assembly for an aircraft, Propeller and, A motor assembly coupled to the propeller, Heat exchanger, An oil passage configured to thermally couple the heat exchanger to the motor assembly, comprising an oil passage passing through the motor assembly and the heat exchanger, A nacelle mechanically coupled to the motor assembly, the nacelle including an air inlet, Equipped with, The heat exchanger is positioned at the air inlet. Propeller assembly. 69. A propeller assembly for an aircraft, Propeller hub and, A propeller blade coupled to the propeller hub, A spinner coupled to the propeller hub, A spinner rod connected to the propeller hub, The conductive part, A motor configured to rotate the propeller hub, the propeller blades, the spinner, the spinner rod, and the conductive part, A magnet suspended from the spinner rod, which is rotationally separated from the spinner rod by a bearing, Equipped with, When the propeller rotates and manages ice formation on the surface of the propeller assembly, the magnet is configured to generate an electric current in the conductive portion. Propeller assembly. 70. The conductive part includes a metal sheet. The propeller assembly according to Clause 69, wherein the current includes eddy currents for generating heat in the conductive portion. 71. The conductive part includes windings, The propeller assembly according to clause 69 or 70, wherein the current generates an electric current in the conductive portion. 72. The propeller assembly according to any one of the clauses 69 to 71, wherein the conductive portion is located on the side surface of the spinner. 73. The propeller assembly according to any one of the clauses 69 to 72, wherein the conductive portion is located in front of the spinner. 74. The propeller assembly according to any one of the clauses 69 to 73, wherein the conductive portion is located in the propeller hub. 75. A propeller assembly according to any one of the clauses 69 to 74, further comprising a wiring path configured to conduct heat or electricity from the conductive portion to at least one of the spinner or the propeller blades. 76. The propeller assembly according to Clause 75, further comprising a switch configured to enable or disable the connection between the conductive portion and the wiring path. 77. The propeller assembly according to Clause 76, wherein the switch comprises a thermostat switch configured to disable the switch when the temperature of the switch reaches a predetermined temperature. 78. The propeller assembly according to Clause 76, wherein the switch is configured to be controlled using wireless communication. 79. The propeller assembly according to Clause 76, wherein the switch is configured to be powered by the current generated in the conductive portion. 80. A propeller assembly according to any one of the clauses 69 to 79, further comprising a magnetic field sensor configured to detect the magnetic flux of the magnet and transmit a signal to the motor based on the detection. 81. The propeller assembly according to clause 80, wherein the motor controller is configured to determine the rotational position of the propeller assembly based on the signal. 82. A propeller assembly for an aircraft, Propeller hub and, A propeller blade coupled to the propeller hub, A spinner coupled to the propeller hub, A spinner rod connected to the propeller hub, The conductive portion coupled to the spinner rod, A bearing is configured to surround the spinner rod and support an array of magnets around the conductive portion, A motor configured to rotate the propeller hub, the propeller blades, the spinner, the spinner rod, and the conductive part, Equipped with, A propeller assembly in which, when the propeller rotates and manages ice formation on the surface of the propeller assembly, the array of magnets is configured to generate an electric current in the conductive portion. 83. The propeller assembly described in Clause 82, further comprising a counterweight configured to maintain the orientation of the bearing relative to the direction of gravity. 84. A propeller assembly for an aircraft, The rotating part, Propeller hub and, A propeller blade coupled to the propeller hub, A spinner coupled to the propeller hub, The conductive part, A rotating part, A motor configured to rotate the aforementioned rotating part, A magnet configured to remain stationary relative to the motor, Equipped with, The magnet is configured to generate an electric current in the conductive portion when the rotating portion rotates in order to manage ice formation on the surface of the rotating portion. Propeller assembly. 85. The conductive portion includes a metal sheet, The propeller assembly according to Clause 84, wherein the current includes eddy currents for generating heat in the conductive portion. 86. The conductive portion includes a winding, The propeller assembly according to clause 84 or 85, wherein the current generates an electric current in the conductive portion. 87. The propeller assembly according to any one of the clauses 84 to 86, wherein the conductive portion is located on the propeller hub or on a propeller flange coupled to the propeller hub. 88. The propeller assembly according to any one of the clauses 84 to 87, wherein the conductive portion is located on the propeller blade. 89. The propeller assembly according to any one of the clauses 84 to 88, wherein the conductive portion includes a structural support for the propeller blade. 90. A propeller assembly according to any one of the clauses 84 to 89, wherein the conductive portion includes a lightning grounding path for the propeller blade. 91. A propeller assembly according to any one of the clauses 84 to 90, further comprising a wiring path configured to conduct heat or electricity from the conductive portion to at least one of the spinner or the propeller blades. 92. The propeller assembly according to clause 91, further comprising a switch configured to enable or disable the connection between the conductive portion and the wiring path. 93. The propeller assembly according to Clause 92, wherein the switch comprises a thermostat switch configured to disable the switch when the temperature of the switch reaches a predetermined temperature. 94. The propeller assembly according to Clause 92, wherein the switch is configured to be controlled using wireless communication. 95. The propeller assembly according to Clause 94, wherein the switch is configured to be powered by the current generated in the conductive portion. 96. A propeller assembly according to any one of the clauses 84 to 95, further comprising a magnetic field sensor configured to detect the magnetic flux of the magnet and transmit a signal to the motor based on the detection. 97. The propeller assembly according to Clause 96, wherein the motor controller is configured to determine the rotational position of the propeller assembly based on the signal. 98. A propeller assembly according to any of the clauses 84 to 97, wherein the magnets include permanent magnets. 99. A propeller assembly according to any of the clauses 84 to 98, wherein the magnet includes an electromagnet. 100. The propeller assembly according to Clause 99, further comprising a DC power circuit configured to provide DC power to the electromagnet. 101. The propeller assembly according to Clause 99, further comprising an AC power circuit configured to provide AC power to the electromagnet. 102. The rotating portion further includes a propeller shaft configured to be coupled to the propeller hub and rotated by the motor, The propeller assembly further comprises a spinner rod configured to pass through the propeller shaft and to be rotationally separated from the propeller shaft, A propeller assembly according to any one of the clauses 84 to 101, wherein the magnet includes a first magnet mechanically coupled to the spinner rod. 103. The propeller assembly according to Clause 102, further comprising a second magnet mechanically coupled to the spinner rod at a position diagonally opposite to the first magnet with respect to the spinner rod. 104. The propeller assembly according to clause 102 or 103, further comprising a pitch control unit, wherein the spinner rod includes a pitch control rod configured to actuate the pitch control unit. 105. The propeller assembly according to clause 104, wherein the spinner rod is rotationally separated from the pitch control unit by a bearing. 106. The propeller assembly according to clause 104 or 105, wherein the pitch control unit includes a yoke and a blade operating pin. 107. A method for managing icing on an aircraft, To determine the icing conditions of the aforementioned aircraft, This includes performing propeller modulation based on the icing conditions, and performing the propeller modulation, To induce a first ice management cycle in a first symmetrical pair of propellers of the aircraft, To induce a second ice management cycle in a second symmetrical pair of the aircraft's propellers, Includes, The first ice management cycle occurs at a first time interval that is different from the second time interval of the second ice management cycle. method. 108. The method according to clause 107, wherein the determination of the icing condition is based on a primary ice detector. 109. The method according to Clause 107 or 108, wherein the determination of icing conditions is based on input from a flight control system or pilot, and such input indicates the presence of certain icing conditions. 110. Determining the aircraft status, The propeller modulation is performed when the aircraft state satisfies one or more predefined parameters. The method described in any of clauses 107 to 109, further including the method described in any of clauses 107 to 109. 111. The method according to Clause 110, wherein one or more predefined parameters include one of the following: control margin status, current bank angle, load factor, vertical airspeed versus command airspeed, altitude, propulsion system, signal integrity, or flight mode. 112. The method according to any one of the clauses 107 to 111, wherein the propeller modulation includes modulating one of the revolutions per minute (RPM), blade pitch angle, torque, or propeller tilt angle. 113. The method according to any one of the clauses 107 to 112, wherein the propeller modulation includes modulating RPM, and the first ice management cycle includes increasing the RPM of a first symmetrical pair of propellers by at least 50 percent during the first time interval. 114. The method according to any one of the clauses 107 to 112, wherein the propeller modulation includes modulating RPM, and the first ice management cycle includes increasing the RPM of a first symmetrical pair of propellers to at least 80 percent of the maximum RPM during the first time interval. 115. The method according to any one of the clauses 107 to 112, wherein the propeller modulation includes modulating the blade pitch angle, and the first ice management cycle includes changing the blade pitch angle of a first symmetrical pair of propellers by at least 5 degrees during the first time interval. 116. The method according to clause 115, further comprising changing the blade pitch angle of the first symmetrical pair of propellers by at least 5 degrees at least four times during the first time interval. 117. The method according to any one of the clauses 107 to 116, wherein the propeller modulation includes modulating torque, and the first ice management cycle includes changing the torque of a first symmetrical pair of propellers by at least 50 percent during the first time interval. 118. The propeller modulation includes modulating the torque, and the first ice management cycle is The method according to any one of the clauses 107 to 116, comprising increasing the torque of a first symmetrical pair of propellers from an initial torque value to within 80 percent of the maximum torque, and decreasing the torque of the first symmetrical pair of propellers to the initial torque, during a first time interval. 119. The method according to any one of the clauses 107 to 118, wherein the propeller modulation includes modulating the propeller tilt angle, and the first ice management cycle includes changing the tilt angle of a first symmetrical pair of propellers by at least 10 degrees during the first time interval. 120. The method according to any one of the clauses 107-107 or 115-119, wherein the propeller modulation comprises modulating RPM, and the first ice management cycle comprises increasing the first RPM of the first symmetric pair of propellers to at least 80 percent of the second RPM of the second symmetric pair of propellers during the first time interval. 121. The method according to clause 120, further comprising the first ice management cycle reducing the second RPM of the second symmetric pair of propellers during the first time interval to compensate for the increased RPM of the first symmetric pair of propellers. 122. The method according to clause 120 or 121, wherein the second ice management cycle includes increasing the second RPM of the second symmetric pair of propellers to at least 80 percent of the first RPM of the first symmetric pair of propellers during the second time interval. 123. The method according to any one of the clauses 120 to 122, further comprising the second ice management cycle reducing the first RPM of the first symmetric pair of propellers during the second time interval to compensate for the increased RPM of the second symmetric pair of propellers. 124. The method according to any one of the clauses 107-114 or 117-123, wherein the propeller modulation includes modulating the blade pitch angle, and the first ice management cycle includes changing the first blade pitch angle of the first symmetrical propeller by at least 5 degrees relative to the second blade pitch angle of the second symmetrical propeller during the first time interval. 125. The method according to clause 124, further comprising increasing the second RPM of the second symmetrical pair of propellers during the first time interval, the first ice management cycle. 126. The method according to clause 124 or 125, wherein the second ice management cycle includes changing the second blade pitch angle of the second symmetrical pair of propellers by at least 5 degrees relative to the first blade pitch angle of the first symmetrical pair of propellers during the second time interval. 127. The method according to any one of the clauses 107-116 or 119-126, wherein the propeller modulation includes modulating torque, and the first ice management cycle includes increasing the torque of a first symmetrical pair of propellers from an initial torque value to a first torque value, and decreasing the torque of the first symmetrical pair of propellers from the first torque value to a second torque value. 128. The method according to Clause 127, wherein the first torque value is within 80 percent of the maximum torque value of the first symmetrical pair of propellers. 129. The method according to clause 127 or 128, wherein the second torque value is less than 50 percent of the initial torque value of the first symmetrical pair of the propellers. 130. The method according to any one of the clauses 127 to 129, wherein the first ice management cycle further comprises increasing the second RPM of the second symmetrical pair of propellers during the first time interval. 131. The method according to any one of the clauses 107 to 130, wherein the propeller modulation includes modulating the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of a first symmetrical pair of propellers by at least 10 degrees. 132. The method according to clause 131, further comprising increasing the second RPM of the second symmetrical pair of propellers during the first time interval, the first ice management cycle. 133. The method according to any one of the claims 107 to 132, wherein the first symmetrical pair of propellers includes a first outermost propeller from a first side of the aircraft body and a second outermost propeller from a second side of the aircraft body. 134. The method according to Clause 133, wherein the second symmetrical pair of propellers includes a third propeller located inside the first propeller on the first side of the body of the aircraft, and a fourth propeller located inside the second propeller on the second side of the body of the aircraft. 135. The method according to Clause 134, wherein the propeller modulation is performed to induce a third ice management cycle in a third symmetrical pair of propellers of the aircraft, the third ice management cycle occurring at a third time interval, the third time interval being different from the first time interval and the second time interval. 136. The method according to Clause 135, wherein the third symmetrical pair of propellers includes a fifth propeller between the first propeller and the third propeller on the first side of the body of the aircraft, and a sixth propeller between the second propeller and the fourth propeller on the second side of the body of the aircraft. 137. The method according to any one of the clauses 107 to 136, further comprising performing the propeller modulation repeatedly at time intervals. 138. The method according to any one of the clauses 107 to 137, wherein the propeller modulation is performed to induce the first ice management cycle and the second ice management cycle at non-overlapping time intervals. 139. The method according to any one of the claims 107 to 138, wherein the first symmetrical pair of propellers and the second symmetrical pair of propellers include a pair of tilt propellers. 140. The first ice management cycle is The method according to any one of the claims 107 to 139, further comprising rotating a symmetrical pair of lift propellers between a first angular position and a second angular position, wherein the first angular position is offset from the second angular position by a multiple of 30 degrees. 141. The method according to clause 140, wherein each lift propeller of the symmetrical pair of lift propellers is positioned behind the corresponding tilt propeller of the first symmetrical pair of tilt propellers in the forward flight direction. 142. The method according to clause 140 or 141, wherein each lift propeller of the symmetrical pair of lift propellers is located further from the aircraft body than the corresponding tilt propeller of the first symmetrical pair of tilt propellers. 143. The method according to any one of the clauses 139 to 142, wherein each lift propeller of the symmetrical pair of lift propellers is positioned closer to the aircraft body than the corresponding tilt propeller of the first symmetrical pair of tilt propellers. 144. The method according to any one of the claims 107 to 138, wherein the first symmetrical pair of propellers and the second symmetrical pair of propellers include a pair of lift propellers. 145. The method according to Clause 144, wherein the first ice management cycle includes rotating a first symmetrical pair of propellers between a first angular position and a second angular position, the first angular position being offset from the second angular position by a multiple of 30 degrees. 146. The method according to Clause 145, wherein rotating the first symmetrical pair of propellers includes rotating the first lift propeller of the first symmetrical pair of propellers in the opposite direction to the second lift propeller of the first symmetrical pair of propellers. 147. The method according to any one of clauses 107 to 146, wherein performing the propeller modulation includes performing the first ice management cycle at periodic intervals based on a predetermined schedule to manage asymmetric icing. 148. The method according to any one of clauses 107 to 147, further including performing the propeller modulation at periodic intervals to manage asymmetric icing. 149. A computer-readable medium storing a set of instructions executable by at least one processor of a device, the set of instructions causing the device to perform operations including the method according to any one of clauses 107 to 148. 150. A propeller assembly for an aircraft, a propeller shaft, a propeller hub coupled to the propeller shaft, propeller blades coupled to the propeller hub, a spinner coupled to the propeller hub, a conductive portion, a motor configured to rotate the propeller shaft, the propeller hub, the propeller blades, the spinner, and the conductive portion, a spinner rod passing through the propeller shaft and configured to be rotationally disengaged from the propeller shaft, a first magnet attached to the spinner rod, comprising, a propeller assembly, wherein when the propeller rotates to manage icing on the surface of the propeller assembly, the first magnet is configured to generate an electric current in the conductive portion. 151. The propeller assembly according to clause 150, further comprising a pitch control unit, wherein the spinner rod includes a pitch control rod configured to operate the pitch control unit. 152. The propeller assembly according to clause 151, wherein the pitch control unit includes a yoke and a blade operating pin. 153. The propeller assembly according to either clause 151 or 152, wherein the spinner rod is rotationally separated from the pitch control unit by a bearing. 154. A propeller assembly according to any one of the clauses 151 to 153, further comprising a second magnet attached to the spinner rod at a position diagonally opposite to the first magnet with respect to the spinner rod. 155. A propeller assembly for an aircraft, It is a propeller, Hub and, A plurality of propeller blades, each of which includes a blade channel inside the propeller blade and is configured to circulate fluid, Including propellers, A motor assembly configured to rotate the propeller around a rotation axis, An oil passage is configured to circulate oil through the motor assembly and through each blade channel of the plurality of propeller blades, thereby thermally coupling the motor assembly to the plurality of propeller blades, Equipped with, A propeller assembly configured to transfer heat from the motor assembly to the external environment outside the propeller assembly by heat conduction through the propeller blades. 156. The propeller assembly according to Clause 155, wherein at least 30% of the heat generated by the motor assembly during the operation of the propeller assembly is transferred to the external environment by heat conduction through the propeller blades. 157. The propeller assembly according to Clause 155, wherein at least 50% of the heat generated by the motor assembly during the operation of the propeller assembly is transferred to the external environment by heat conduction through the propeller blades. 158. A propeller assembly according to any one of the plurality of propeller blades, further comprising a heat conductor configured to conduct heat from the blade channel to a portion of the propeller blade that is radially outward from the blade channel. 159. The propeller assembly according to any one of clauses 155 to 158, wherein the blade channel extends radially outward through the blade by a distance of 70% or less of the blade radius when measured from the axis of rotation. 160. The propeller assembly according to any one of clauses 155 to 159, wherein the blade channel extends radially outward through the blade by no more than 50% of the blade radius when measured from the axis of rotation. 161. The propeller assembly according to any of clauses 155 to 160, wherein the blade channel extends radially outward through the blade by no more than 30% of the blade radius when measured from the axis of rotation. 162. The propeller further includes a spinner, the spinner having a spinner channel configured to circulate a fluid, The oil passage is further configured to circulate oil through the spinner channel and thermally couple the motor assembly to the spinner. A propeller assembly as described in any of clauses 155 to 161. 163. A propeller assembly for an aircraft, It is a propeller, Hub and, A propeller comprising: a plurality of propeller blades, each of which includes a blade channel inside the propeller blade and is configured to circulate fluid; A motor assembly configured to rotate the propeller around a rotation axis, An oil passage is configured to circulate oil through the motor assembly and through each blade channel of the plurality of propeller blades, thereby thermally coupling the motor assembly to the plurality of propeller blades, Equipped with, The plurality of propeller blades constitute the single heat exchanger of the motor assembly. Propeller assembly. 164. The propeller assembly according to Clause 163, wherein at least 30% of the heat generated by the motor assembly during the operation of the propeller assembly is transferred to the external environment by heat conduction through the propeller blades. 165. The propeller assembly according to Clause 163, wherein at least 50% of the heat generated by the motor assembly during the operation of the propeller assembly is transferred to the external environment by heat conduction through the propeller blades. 166. A propeller assembly according to any one of the clauses 163 to 165, wherein each of the plurality of propeller blades further comprises a heat conductor configured to conduct heat from the blade channel to a portion of the propeller blade that is radially outward from the blade channel. 167. The propeller assembly according to any of clauses 163 to 166, wherein the blade channel extends radially outward through the blade by no more than 70% of the blade radius when measured from the axis of rotation. 168. The propeller assembly according to any of clauses 163 to 167, wherein the blade channel extends radially outward through the blade by no more than 50% of the blade radius when measured from the axis of rotation. 169. A propeller assembly according to any of clauses 163 to 168, wherein the blade channel extends radially outward through the blade by no more than 30% of the blade radius when measured from the axis of rotation. 170. The propeller further includes a spinner, the spinner having a spinner channel configured to circulate a fluid, The propeller assembly according to any one of the clauses 163 to 169, wherein the oil passage is further configured to circulate oil through the spinner channel and to thermally couple the motor assembly to the spinner. 171. A method for managing icing on an aircraft, To determine the icing conditions of the aforementioned aircraft, This includes performing propeller modulation based on the icing conditions, and performing the propeller modulation, Inducing a first ice management cycle in a first set of one or more propellers of the aircraft, The method includes inducing a second ice management cycle in a second set of one or more propellers of the aircraft, wherein the first set of one or more propellers differs from the second set of one or more propellers in that the first ice management cycle occurs at a first time interval different from the second time interval of the second ice management cycle. method. 172. The method according to Clause 171, wherein the determination of the icing condition is based on a primary ice detector. 173. The method of Clause 171 or 172, wherein the determination of icing conditions is based on input from the flight control system or pilot indicating the presence of icing conditions. 174. Determining the aircraft status, The method according to any one of the clauses 171 to 173, further comprising performing propeller modulation when the aircraft condition satisfies one or more predefined parameters. 175. The method according to Clause 174, wherein one or more predefined parameters include one of the following: control margin status, current bank angle, load factor, vertical airspeed versus command airspeed, altitude, propulsion system, signal integrity, or mode of flight. 176. The method according to any one of the clauses 171 to 175, wherein the propeller modulation includes modulating one of the following: revolutions per minute (RPM), blade pitch angle, torque, or propeller tilt angle. 177. The method according to any one of the clauses 171 to 176, wherein the propeller modulation includes modulating RPM, and the first ice management cycle includes increasing the RPM of a first set of the one or more propellers by at least 50 percent during the first time interval. 178. The method according to any one of the clauses 171 to 176, wherein the propeller modulation includes modulating RPM, and the first ice management cycle includes increasing the RPM of a first set of one or more propellers to at least 80 percent of the maximum RPM during the first time interval. 179. The method according to any one of the clauses 171 to 176, wherein the propeller modulation includes modulating the blade pitch angle, and the first ice management cycle includes changing the blade pitch angle of a first set of one or more propellers by at least 5 degrees during the first time interval. 180. The method according to Clause 179, further comprising changing the blade pitch angle of the first set of the one or more propellers by at least 5 degrees at least four times during the first time interval. 181. The method according to any one of the clauses 171 to 180, wherein the propeller modulation includes modulating torque, and the first ice management cycle includes changing the torque of a first set of one or more propellers by at least 50 percent during the first time interval. 182. The propeller modulation includes modulating the torque, and the first ice management cycle is During the first time interval, the torque of a first set of one or more propellers is increased from an initial torque value to within 80 percent of the maximum torque, and the torque of the first set of one or more propellers is decreased to the initial torque. The method described in any of clauses 171 to 180. 183. The method according to any one of the clauses 171 to 182, wherein the propeller modulation includes modulating the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of a first set of one or more propellers by at least 10 degrees during the first time interval. 184. The propeller modulation includes modulating the RPM, and the first ice management cycle includes increasing, during the first time interval, the first RPM of the first set of the one or more propellers to at least 80 percent of the second RPM of the second set of the one or more propellers, according to the method according to any one of clauses 171 - 176 or 179 - 183. 185. The method according to clause 184, wherein the first ice management cycle further includes decreasing the second RPM of the second set of the one or more propellers during the first time interval to compensate for the increased RPM of the first set of the one or more propellers. 186. The method according to clause 184 or 185, wherein the second ice management cycle includes increasing, during the second time interval, the second RPM of the second set of the one or more propellers to at least 80 percent of the first RPM of the first set of the one or more propellers. 187. The method according to any one of clauses 184 - 186, wherein the second ice management cycle further includes decreasing the first RPM of the first set of the one or more propellers during the second time interval to compensate for the increased RPM of the second set of the one or more propellers. 188. The propeller modulation includes modulating the blade pitch angle, and the first ice management cycle includes changing, during the first time interval, the first blade pitch angle of the first set of the one or more propellers by at least 5 degrees with respect to the second blade pitch angle of the second set of the one or more propellers, according to the method according to any one of clauses 171 - 178 or 181 - 187. 189. The method according to clause 188, wherein the first ice management cycle further includes increasing the second RPM of the second set of the one or more propellers during the first time interval. 190. The method according to clause 188 or 189, wherein the second ice management cycle includes changing, during the second time interval, the second blade pitch angle of the second set of the one or more propellers by at least 5 degrees with respect to the first blade pitch angle of the first set of the one or more propellers. 191. The method according to any one of the clauses 171-180 or 183-190, wherein the propeller modulation includes modulating torque, and the first ice management cycle includes increasing the torque of a first set of the one or more propellers from an initial torque value to a first torque value, and decreasing the torque of the first set of the one or more propellers from the first torque value to a second torque value. 192. The method according to clause 191, wherein the first torque value is within 80 percent of the maximum torque value of the first set of the one or more propellers. 193. The method according to clause 191 or 192, wherein the second torque value is less than 50 percent of the initial torque value of the first set of the one or more propellers. 194. The method according to any one of the clauses 191 to 193, wherein the first ice management cycle further comprises increasing the second RPM of the second set of the one or more propellers during the first time interval. 195. The method according to any one of the clauses 171 to 194, wherein the propeller modulation includes modulating the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of a first set of one or more propellers by at least 10 degrees. 196. The method according to clause 195, further comprising increasing the second RPM of the second set of the one or more propellers during the first time interval, the first ice management cycle. 197. The method according to any one of the claims 171 to 196, wherein the first set of the one or more propellers includes an outermost propeller from a first side of the aircraft body and an outermost propeller from a second side of the aircraft body, forming a first symmetrical pair of propellers. 198. The method according to Clause 197, wherein the second set of one or more propellers includes an innermost propeller inside the outermost propeller on the first side of the body of the aircraft, and an innermost propeller inside the outermost propeller on the second side of the body of the aircraft, forming a second symmetrical pair of propellers. 199. The method according to Clause 198, wherein the propeller modulation is performed to induce a third ice management cycle in a third symmetrical pair of propellers of the aircraft, the third ice management cycle occurring at a third time interval, the third time interval being different from the first time interval and the second time interval. 200. The method according to Clause 199, wherein the third symmetrical pair of propellers includes an intermediate propeller between the outermost and innermost propellers on the first side of the body of the aircraft, and an intermediate propeller between the outermost and innermost propellers on the second side of the body of the aircraft. 201. The method according to any one of the provisions 171 to 200, further comprising performing the propeller modulation repeatedly at time intervals. 202. The method according to any one of the clauses 171 to 201, wherein the propeller modulation is performed to induce the first ice management cycle and the second ice management cycle at non-overlapping time intervals. 203. The method according to any one of the clauses 171 to 202, wherein the first set of the one or more propellers and the second set of the one or more propellers include tilt propellers. 204. The first ice management cycle described above is The invention further includes rotating a lift propeller between a first angular position and a second angular position, wherein the first angular position is offset from the second angular position by a multiple of 30 degrees. The method described in any of clauses 171 to 203. 205. The method according to clause 204, wherein the lift propeller is located behind one of the first set of one or more propellers in the forward flight direction. 206. The method according to Clause 204, wherein the lift propeller is located further from the body of the aircraft than one of the first set of the one or more propellers. 207. The method according to any one of the clauses 203 to 206, wherein the lift propeller is located closer to the body of the aircraft than one of the first set of the one or more propellers. 208. The method according to any one of the claims 171 to 202, wherein the first set of the one or more propellers and the second set of the one or more propellers include lift propellers. 209. The method according to Clause 208, wherein the first ice management cycle includes rotating a first lift propeller of a first set of one or more propellers between a first angular position and a second angular position, the first angular position being offset from the second angular position by a multiple of 30 degrees. 210. The method according to Clause 209, wherein the first ice management cycle includes rotating a second lift propeller of a first set of the one or more propellers in the opposite direction to the first lift propeller. 211. The method according to any one of the clauses 171 to 210, wherein propeller modulation is performed to perform the first ice management cycle at periodic intervals based on a predetermined schedule in order to manage asymmetric icing. 212. The method according to any one of the clauses 171 to 211, further comprising performing propeller modulation at periodic intervals to manage asymmetric icing. 213. A computer-readable medium for storing a set of instructions that can be executed by at least one processor of a device, causing the device to perform an operation including the method described in any of the clauses 171 to 212. 214. A flight control system for an aircraft, Memory for storing instructions, A processor configured to execute the aforementioned instructions and cause the flight control system to perform any of the methods described in clauses 171 to 212, A flight control system equipped with the following features. The above description is provided for illustrative purposes only. It is not exhaustive and does not limit the present invention to the disclosed forms or embodiments themselves. Modifications and adaptations of the present invention will be apparent to those skilled in the art, given the specification and practice of the disclosed embodiments of the present invention disclosed herein.

Claims

1. A method for managing icing on aircraft, To determine the icing conditions of the aforementioned aircraft, This includes performing propeller modulation based on the aforementioned icing conditions, Performing the aforementioned propeller modulation is To induce a first ice management cycle in a first set of one or more propellers of the aircraft, Inducing a second ice management cycle in a second set of one or more propellers of the aircraft, Includes, The first set of one or more propellers differs from the second set of one or more propellers, and the first ice management cycle occurs at a first time interval that is different from the second time interval of the second ice management cycle. method.

2. The method according to claim 1, wherein the determination of the ice formation status is based on a primary ice detector.

3. The method according to claim 1 or 2, wherein the determination of the icing condition is based on input from a flight control system or from a pilot, and the input indicates the presence of a certain icing condition.

4. Determining the aircraft's condition, The propeller modulation is performed when the aircraft state satisfies one or more predefined parameters. The method according to any one of claims 1 to 3, further comprising:

5. The method according to claim 4, wherein the one or more predefined parameters include one of the following: control margin status, current bank angle, load factor, vertical airspeed versus command airspeed, altitude, propulsion system, signal integrity, or flight mode.

6. The method according to any one of claims 1 to 5, wherein the propeller modulation includes modulating one of the following: revolutions per minute (RPM), blade pitch angle, torque, or propeller tilt angle.

7. The method according to any one of claims 1 to 6, wherein the propeller modulation includes modulating the RPM, and the first ice management cycle includes increasing the RPM of a first set of one or more propellers by at least 50 percent during the first time interval.

8. The method according to any one of claims 1 to 6, wherein the propeller modulation includes modulating the RPM, and the first ice management cycle includes increasing the RPM of a first set of one or more propellers to at least 80 percent of the maximum RPM during the first time interval.

9. The method according to any one of claims 1 to 6, wherein the propeller modulation includes modulating the blade pitch angle, and the first ice management cycle includes changing the blade pitch angle of a first set of one or more propellers by at least 5 degrees during the first time interval.

10. The method according to claim 9, further comprising changing the blade pitch angle of a first set of one or more propellers by at least 5 degrees at least four times during the first time interval.

11. The method according to any one of claims 1 to 10, wherein the propeller modulation includes modulating torque, and the first ice management cycle includes changing the torque of a first set of one or more propellers by at least 50 percent during the first time interval.

12. The propeller modulation includes modulating the torque, and the first ice management cycle is The method according to any one of claims 1 to 10, comprising increasing the torque of a first set of one or more propellers from an initial torque value to within 80 percent of a maximum torque during the first time interval, and decreasing the torque of the first set of one or more propellers to the initial torque.

13. The method according to any one of claims 1 to 12, wherein the propeller modulation includes modulating the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of a first set of one or more propellers by at least 10 degrees during the first time interval.

14. The method according to any one of claims 1 to 6 or 9 to 13, wherein the propeller modulation includes modulating RPM, and the first ice management cycle includes increasing the first RPM of a first set of the one or more propellers to at least 80 percent of the second RPM of a second set of the one or more propellers during the first time interval.

15. The method according to claim 14, further comprising the first ice management cycle reducing the second RPM of the second set of the one or more propellers during the first time interval to compensate for the increased RPM of the first set of the one or more propellers.

16. The method according to claim 14 or 15, wherein the second ice management cycle includes increasing the second RPM of the second set of the one or more propellers to at least 80 percent of the first RPM of the first set of the one or more propellers during the second time interval.

17. The method according to any one of claims 14 to 16, further comprising the second ice management cycle reducing the first RPM of the first set of the one or more propellers during the second time interval to compensate for the increased RPM of the second set of the one or more propellers.

18. The method according to any one of claims 1 to 8 or 11 to 17, wherein the propeller modulation includes modulating the blade pitch angle, and the first ice management cycle includes changing the first blade pitch angle of a first set of one or more propellers by at least 5 degrees relative to the second blade pitch angle of a second set of one or more propellers during the first time interval.

19. The method according to claim 18, further comprising increasing the second RPM of the second set of the one or more propellers during the first time interval.

20. The method according to claim 18 or 19, wherein the second ice management cycle includes changing the second blade pitch angle of the second set of the one or more propellers by at least 5 degrees relative to the first blade pitch angle of the first set of the one or more propellers during the second time interval.

21. The method according to any one of claims 1 to 10 or 13 to 20, wherein the propeller modulation includes modulating torque, and the first ice management cycle includes increasing the torque of a first set of one or more propellers from an initial torque value to a first torque value, and decreasing the torque of the first set of one or more propellers from the first torque value to a second torque value.

22. The method according to claim 21, wherein the first torque value is within 80 percent of the maximum torque value of the first set of one or more propellers.

23. The method according to claim 21 or 22, wherein the second torque value is less than 50 percent of the initial torque value of the first set of the one or more propellers.

24. The method according to any one of claims 21 to 23, further comprising increasing the second RPM of the second set of the one or more propellers during the first time interval.

25. The method according to any one of claims 1 to 24, wherein the propeller modulation includes modulating the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of a first set of one or more propellers by at least 10 degrees.

26. The method according to claim 25, further comprising increasing the second RPM of the second set of the one or more propellers during the first time interval.

27. The method according to any one of claims 1 to 26, wherein the first set of one or more propellers includes an outermost propeller from a first side of the aircraft body and an outermost propeller from a second side of the aircraft body, forming a first symmetrical pair of propellers.

28. The method according to claim 27, wherein the second set of one or more propellers includes an innermost propeller inside the outermost propeller on the first side of the body of the aircraft, and an innermost propeller inside the outermost propeller on the second side of the body of the aircraft, forming a second symmetrical pair of propellers.

29. The method according to claim 28, wherein the propeller modulation includes inducing a third ice management cycle in a third symmetrical pair of propellers of the aircraft, the third ice management cycle occurring at a third time interval, the third time interval being different from the first time interval and the second time interval.

30. The method according to claim 29, wherein the third symmetrical pair of propellers includes an intermediate propeller between the outermost and innermost propellers on the first side of the body of the aircraft, and an intermediate propeller between the outermost and innermost propellers on the second side of the body of the aircraft.

31. The method according to any one of claims 1 to 30, further comprising performing the propeller modulation repeatedly at time intervals.

32. The method according to any one of claims 1 to 31, wherein the propeller modulation is performed to induce the first ice management cycle and the second ice management cycle at non-overlapping time intervals.

33. The method according to any one of claims 1 to 32, wherein the first set of one or more propellers and the second set of one or more propellers include tilt propellers.

34. The first ice management cycle described above is The method according to any one of claims 1 to 33, further comprising rotating a lift propeller between a first angular position and a second angular position, wherein the first angular position is offset from the second angular position by a multiple of 30 degrees.

35. The method according to claim 34, wherein the lift propeller is located behind one of the first set of one or more propellers in the forward flight direction.

36. The method according to claim 34, wherein the lift propeller is located further from the aircraft body than one of the first set of the one or more propellers.

37. The method according to any one of claims 33 to 36, wherein the lift propeller is located closer to the body of the aircraft than one of the first set of the one or more propellers.

38. The method according to any one of claims 1 to 32, wherein the first set of one or more propellers and the second set of one or more propellers include lift propellers.

39. The first ice management cycle described above is Increasing the RPM of the lift propellers of the first set of one or more propellers from the stationary storage position, The method according to claim 38, comprising reducing the RPM of the lift propeller to return the lift propeller to the stationary storage position.

40. The method according to claim 38, wherein the first ice management cycle includes rotating a first lift propeller of a first set of one or more propellers between a first angular position and a second angular position, the first angular position being offset from the second angular position by a multiple of 30 degrees.

41. The method according to claim 40, wherein the first ice management cycle includes rotating a second lift propeller of a first set of one or more propellers in the opposite direction to the first lift propeller.

42. The method according to any one of claims 1 to 41, wherein the propeller modulation includes performing the first ice management cycle at periodic intervals based on a predetermined schedule in order to manage asymmetric ice formation.

43. The method according to any one of claims 1 to 42, further comprising performing propeller modulation at periodic intervals to manage asymmetric icing.

44. A computer-readable medium for storing a set of instructions executable by at least one processor of a device, which causes the device to perform an operation including the method according to any one of claims 1 to 43.

45. A flight control system for aircraft, Memory for storing instructions, A flight control system comprising: a processor configured to execute the aforementioned instructions and cause the flight control system to perform the method described in any one of claims 1 to 43.

46. A propeller assembly for an aircraft, Propeller and, A motor assembly coupled to the propeller, Heat exchanger, An oil passage configured to thermally couple the heat exchanger to the motor assembly, comprising an oil passage including a first segment, a second segment, and a third segment, A nacelle mechanically coupled to the motor assembly, the nacelle includes an air inlet configured to direct air to the heat exchanger, the air inlet includes a lower lip relative to the forward flight configuration and an upper lip opposite to the lower lip, the lower lip being further from the motor assembly than the upper lip, The first segment passes through the motor assembly, The second segment passes through the heat exchanger, The third segment passes along the lower lip, A propeller assembly in which the oil passage bypasses the upper lip.

47. The propeller assembly according to claim 46, further comprising a thermally conductive material between the motor assembly and the upper lip, configured to conduct heat from the motor assembly to the upper lip.

48. The nacelle comprises the first material, The thermal conductive material includes a second material different from the first material, The second material has a higher thermal conductivity than the first material. The propeller assembly according to claim 47.

49. The propeller assembly according to claim 47 or 48, wherein the thermal conductive material extends along two sides of the air inlet between the upper lip and the lower lip.

50. The propeller assembly according to any one of claims 47 to 49, wherein the thermal conductive material extends from the inside of the motor assembly to the outside of the motor assembly.

51. The propeller assembly according to claim 50, wherein the thermal conductive material includes a plate extending from the inside of the motor assembly to the outside of the motor assembly.

52. The propeller assembly according to any one of claims 47 to 51, wherein the thermally conductive material encloses the motor assembly.

53. The propeller assembly according to any one of claims 46 to 52, wherein the third segment branches off from the second segment in the oil flow direction and returns to the second segment in the oil flow direction.

54. The propeller assembly according to claim 53, wherein the first segment flows into the second segment in the direction of oil flow and returns from the second segment in the direction of oil flow.

55. The propeller assembly according to any one of claims 46 to 54, further comprising a first flow control valve configured to regulate the oil flow rate through the third segment.

56. The propeller assembly according to claim 55, wherein the first flow control valve is configured to selectively block the oil flow to or from the third segment.

57. The propeller assembly according to claim 55 or 56, further comprising a second flow control valve, wherein the first flow control valve is located on the inlet side of the third segment and the second flow control valve is located on the outlet side of the third segment.

58. The propeller assembly according to any one of claims 46 to 57, wherein the third segment extends along the lower surface of the nacelle with respect to the forward flight configuration.

59. The propeller assembly according to any one of claims 46 to 58, wherein the third segment branches off from the first segment in the oil flow direction at the outlet point of the first segment.

60. The propeller assembly according to claim 59, wherein the third segment flows into the second segment in the oil flow direction.

61. The propeller assembly according to claim 59 or 60, wherein the third segment returns to the first segment in the oil flow direction at the first segment inlet point, and the first segment inlet point is downstream of the first segment outlet point in the oil flow direction.

62. The propeller assembly according to claim 61, wherein the inlet point of the first segment is located upstream of the second segment in the oil flow direction.

63. The propeller assembly according to claim 61, wherein the inlet point of the first segment is located downstream of the second segment in the oil flow direction.

64. The propeller assembly according to any one of claims 46 to 63, wherein the third segment is connected in series within the first segment.

65. The propeller assembly according to any one of claims 46 to 64, wherein a first portion of the first segment flows into the third segment, and the third segment flows into a second portion of the first segment.

66. The propeller assembly according to any one of claims 46 to 65, wherein a first portion of the first segment flows into the third segment, and the third segment flows into a second portion of the first segment.

67. A vertical takeoff and landing aircraft comprising the propeller assembly described in any one of claims 46 to 66, A vertical take-off and landing aircraft in which the propeller, motor assembly, heat exchanger, and nacelle are configured to tilt between an ascent configuration and a cruising configuration relative to the frame of the vertical take-off and landing aircraft.

68. A propeller assembly for an aircraft, It is a propeller, Hub and, A plurality of propeller blades, each of which includes a blade channel inside the propeller blade and is configured to circulate fluid, Including propellers, A motor assembly configured to rotate the propeller around a rotation axis, An oil passage is configured to circulate oil through the motor assembly and through each blade channel of the plurality of propeller blades, thereby thermally coupling the motor assembly to the plurality of propeller blades, Equipped with, A propeller assembly configured to transfer heat from the motor assembly to the external environment outside the propeller assembly by heat conduction through the propeller blades.

69. The propeller assembly according to claim 68, wherein during the operation of the propeller assembly, at least 30% of the heat generated by the motor assembly is transferred to the external environment by heat conduction through the propeller blades.

70. The propeller assembly according to claim 68, wherein during the operation of the propeller assembly, at least 50% of the heat generated by the motor assembly is transferred to the external environment by heat conduction through the propeller blades.

71. The propeller assembly according to any one of claims 68 to 70, wherein each of the plurality of propeller blades further comprises a heat conductor configured to conduct heat from the blade channel to a portion of the propeller blade that is radially outward from the blade channel.

72. The propeller assembly according to any one of claims 68 to 71, wherein the blade channel extends radially outward through the blade for a distance of 70% or less of the blade radius when measured from the axis of rotation.

73. The propeller assembly according to any one of claims 68 to 72, wherein the blade channel extends radially outward through the blade by a distance of 50% or less of the blade radius when measured from the axis of rotation.

74. The propeller assembly according to any one of claims 68 to 73, wherein the blade channel extends radially outward through the blade by a distance of 30% or less of the blade radius when measured from the axis of rotation.

75. The propeller further includes a spinner, the spinner having a spinner channel configured to circulate a fluid, The oil passage is further configured to circulate oil through the spinner channel and thermally couple the motor assembly to the spinner. The propeller assembly according to any one of claims 68 to 74.

76. A propeller assembly for an aircraft, It is a propeller, Hub and, A plurality of propeller blades, each of which includes a blade channel inside the propeller blade and is configured to circulate fluid, Including propellers, A motor assembly configured to rotate the propeller around a rotation axis, An oil passage configured to circulate oil through the motor assembly and through each blade channel of the plurality of propeller blades, thereby thermally coupling the motor assembly to the plurality of propeller blades, Equipped with, The plurality of propeller blades constitute the single heat exchanger of the motor assembly. Propeller assembly.

77. The propeller assembly according to claim 76, wherein during the operation of the propeller assembly, at least 30% of the heat generated by the motor assembly is transferred to the external environment by heat conduction through the propeller blades.

78. The propeller assembly according to claim 76, wherein during the operation of the propeller assembly, at least 50% of the heat generated by the motor assembly is transferred to the external environment by heat conduction through the propeller blades.

79. The propeller assembly according to any one of claims 76 to 78, wherein each of the plurality of propeller blades further comprises a heat conductor configured to conduct heat from the blade channel to a portion of the propeller blade that is radially outward from the blade channel.

80. The propeller assembly according to any one of claims 76 to 79, wherein the blade channel extends radially outward through the blade for a distance of 70% or less of the blade radius when measured from the axis of rotation.

81. The propeller assembly according to any one of claims 76 to 80, wherein the blade channel extends radially outward through the blade by a distance of 50% or less of the blade radius when measured from the axis of rotation.

82. The propeller assembly according to any one of claims 76 to 81, wherein the blade channel extends radially outward through the blade by a distance of 30% or less of the blade radius, as measured from the axis of rotation.

83. The propeller further includes a spinner, the spinner having a spinner channel configured to circulate a fluid, The propeller assembly according to any one of claims 76 to 82, wherein the oil passage is further configured to circulate oil through the spinner channel and thermally couple the motor assembly to the spinner.

84. A propeller assembly for an aircraft, Propeller hub and, A propeller blade coupled to the propeller hub, A spinner coupled to the propeller hub, A spinner rod connected to the propeller hub, The conductive part, A motor configured to rotate the propeller hub, the propeller blades, the spinner, the spinner rod, and the conductive part, A magnet suspended from the spinner rod, which is rotationally separated from the spinner rod by a bearing, Equipped with, A propeller assembly in which, when the propeller rotates and manages ice formation on the surface of the propeller assembly, the magnet is configured to generate an electric current in the conductive portion.

85. The conductive portion includes a metal sheet, The propeller assembly according to claim 84, wherein the current includes eddy currents for generating heat in the conductive portion.

86. The conductive portion includes a winding, The propeller assembly according to claim 84 or 85, wherein the current generates an electric current in the conductive portion.

87. The propeller assembly according to any one of claims 84 to 86, wherein the conductive portion is located on the side surface of the spinner.

88. The propeller assembly according to any one of claims 84 to 87, wherein the conductive portion is located in front of the spinner.

89. The propeller assembly according to any one of claims 84 to 88, wherein the conductive portion is located in the propeller hub.

90. The propeller assembly according to any one of claims 84 to 89, further comprising a wiring path configured to conduct heat or electricity from the conductive portion to at least one of the spinner or the propeller blades.

91. The propeller assembly according to claim 90, further comprising a switch configured to enable or disable the connection between the conductive portion and the wiring path.

92. The propeller assembly according to claim 91, wherein the switch comprises a thermostat switch configured to disable the switch when the temperature of the switch reaches a predetermined temperature.

93. The propeller assembly according to claim 91, wherein the switch is configured to be controlled using wireless communication.

94. The propeller assembly according to claim 91, wherein the switch is configured to be powered by the current generated in the conductive portion.

95. The propeller assembly according to any one of claims 84 to 94, further comprising a magnetic field sensor configured to detect the magnetic flux of the magnet and transmit a signal to the motor based on the detection.

96. The propeller assembly according to claim 95, wherein the motor controller is configured to determine the rotational position of the propeller assembly based on the signal.

97. A propeller assembly for an aircraft, The rotating part, Propeller hub and, A propeller blade coupled to the propeller hub, A spinner coupled to the propeller hub, The conductive part, A rotating part, A motor configured to rotate the aforementioned rotating part, A magnet configured to remain stationary relative to the motor, Equipped with, The magnet is configured to generate an electric current in the conductive portion when the rotating portion rotates in order to manage ice formation on the surface of the rotating portion. Propeller assembly.

98. The conductive portion includes a metal sheet, The propeller assembly according to claim 97, wherein the current includes eddy currents for generating heat in the conductive portion.

99. The conductive portion includes a winding, The propeller assembly according to claim 97 or 98, wherein the current generates an electric current in the conductive portion.

100. The propeller assembly according to any one of claims 97 to 99, wherein the conductive portion is located on the propeller hub or on a propeller flange coupled to the propeller hub.

101. The propeller assembly according to any one of claims 97 to 100, wherein the conductive portion is located on the propeller blade.

102. The propeller assembly according to any one of claims 97 to 101, wherein the conductive portion includes a structural support for the propeller blade.

103. The propeller assembly according to any one of claims 97 to 102, wherein the conductive portion includes a lightning grounding path for the propeller blade.

104. The propeller assembly according to any one of claims 97 to 103, further comprising a wiring path configured to conduct heat or electricity from the conductive portion to at least one of the spinner or the propeller blades.

105. The propeller assembly according to claim 104, further comprising a switch configured to enable or disable the connection between the conductive portion and the wiring path.

106. The propeller assembly according to claim 105, wherein the switch comprises a thermostat switch configured to disable the switch when the temperature of the switch reaches a predetermined temperature.

107. The propeller assembly according to claim 105, wherein the switch is configured to be controlled using wireless communication.

108. The propeller assembly according to claim 107, wherein the switch is configured to be powered by the current generated in the conductive portion.

109. The propeller assembly according to any one of claims 97 to 108, further comprising a magnetic field sensor configured to detect the magnetic flux of the magnet and transmit a signal to the motor based on the detection.

110. The propeller assembly according to claim 109, wherein the motor controller is configured to determine the rotational position of the propeller assembly based on the signal.

111. The propeller assembly according to any one of claims 97 to 110, wherein the magnet includes a permanent magnet.

112. The propeller assembly according to any one of claims 97 to 111, wherein the magnet includes an electromagnet.

113. The propeller assembly according to claim 112, further comprising a DC power circuit configured to supply DC power to the electromagnet.

114. The propeller assembly according to claim 112, further comprising an AC power circuit configured to supply AC power to the electromagnet.

115. The rotating portion further includes a propeller shaft configured to be coupled to the propeller hub and rotated by the motor, The propeller assembly further comprises a spinner rod configured to pass through the propeller shaft and to be rotationally separated from the propeller shaft, The propeller assembly according to any one of claims 97 to 113, wherein the magnet includes a first magnet mechanically coupled to the spinner rod.

116. The propeller assembly according to claim 115, further comprising a second magnet mechanically coupled to the spinner rod at a position diagonally opposite to the first magnet with respect to the spinner rod.

117. The propeller assembly according to claim 115 or 116, further comprising a pitch control unit, wherein the spinner rod includes a pitch control rod configured to actuate the pitch control unit.

118. The propeller assembly according to claim 117, wherein the spinner rod is rotationally separated from the pitch control unit by a bearing.

119. The propeller assembly according to claim 117 or 118, wherein the pitch control unit includes a yoke and a blade operating pin.

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