System and method for managing ice buildup during flight of aircraft

Abstract

Embodiments of the present disclosure provide systems and methods for avoiding ice accretions that may occur during flight of an aircraft, shedding the ice accretions, or otherwise managing the ice accretions. Example systems and methods selectively adjust propeller parameters in a manner that does not disrupt a flight trajectory; directing oil from the lubrication and cooling path to a target section of the ice prone surface in a manner that does not excessively increase the total volume of oil, does not require a larger pump, or does not complicate the system to manage ice build-up; or heat is generated at a target area of the propeller assembly by an electrical heating system utilizing propeller motion.

Description

Systems and methods for managing icing during aircraft flight Cross-reference to related applications

[0001] This application claims priority to International Application No. PCT / US2024 / 044891, filed August 30, 2024, entitled “Systems and Methods for Managing Ice Accretions During Flight of Aircraft,” which in turn claims priority to U.S. Provisional Application No. 63 / 587,117, filed September 30, 2023, entitled “Systems and Methods for Managing eVTOL Flight in Icing,” the contents of which are incorporated herein by reference in their entirety for all purposes. Technical Field

[0002] This disclosure generally relates to the field of powered air vehicles. More specifically, but not limited to, this disclosure relates to innovations in tiltrotor aircraft using electric propulsion systems. Certain aspects of this disclosure generally relate to systems and methods for preventing or eliminating icing in electric aircraft. Other aspects of this disclosure generally relate to improvements in anti-icing or de-icing that can be used in other types of vehicles but provide particular advantages in air vehicles. Background Technology

[0003] Electric vertical takeoff and landing (eVTOL) aircraft typically contain one or more electric propulsion units (“EPUs”), each EPU containing at least one (fully or partially) electric or hybrid electric motor and at least one propeller. The propeller comprises multiple propeller blades (sometimes molded or integrated as a single piece) that rotate around a propeller hub when mechanically driven by a propeller shaft. Each EPU generates thrust by converting electrical power into mechanical shaft power via its motor, thereby causing the propeller blades to rotate. Summary of the Invention

[0004] Embodiments of this disclosure provide systems and methods for preventing or eliminating (collectively, “managing”) icing during flight of any aircraft.

[0005] Some embodiments of this disclosure provide a method for managing icing on an aircraft, the method comprising: determining an icing condition of the aircraft; and performing propeller regulation based on the icing condition, wherein performing the propeller regulation comprises: inducing a first ice management cycle in a first group of one or more propellers of the aircraft; and inducing a second ice management cycle in a second group of one or more propellers of the aircraft, the first group of one or more propellers being different from the second group of one or more propellers, and the first ice management cycle occurring in a first time interval being different from a second time interval of the second ice management cycle.

[0006] Some embodiments of this 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 flow path configured to thermally couple the heat exchanger to the motor assembly, the oil flow path including a first segment, a second segment, and a third segment; and a cabin mechanically coupled to the motor assembly, the cabin including an air inlet configured to direct air to the heat exchanger, the air inlet including a lower lip configured relative to forward flight and an upper lip opposite the lower lip, the lower lip being further away from the motor assembly than the upper lip, wherein: the first segment passes through the motor assembly; the second segment passes through the heat exchanger; the third segment passes along the lower lip; and the oil flow path bypasses the upper lip.

[0007] Some embodiments of this disclosure provide a propeller assembly for an aircraft, the propeller assembly comprising: a propeller including: a hub; and a plurality of propeller blades, each of the plurality of propeller blades including a blade channel located inside the propeller blade and configured to circulate fluid; a motor assembly configured to rotate the propeller about a rotation axis; and an oil flow path configured to circulate oil through the motor assembly and through each of the plurality of propeller blades to thermally couple the motor assembly to the plurality of propeller blades; wherein the propeller assembly is configured to transfer heat from the motor assembly to an external environment outside the propeller assembly via thermal conduction through the propeller blades.

[0008] Some embodiments of this disclosure provide a propeller assembly for an aircraft, the propeller assembly including: a propeller including: a hub; and a plurality of propeller blades, each of the plurality of propeller blades including a blade channel located inside the propeller blade and configured to circulate fluid; a motor assembly configured to rotate the propeller about a rotation axis; and an oil flow path configured to circulate oil through the motor assembly and through each of the plurality of propeller blades to thermally couple the motor assembly to the plurality of propeller blades; wherein the plurality of propeller blades includes a single heat exchanger for the motor assembly.

[0009] Some embodiments of this disclosure provide a propeller assembly for an aircraft, the propeller assembly including: a propeller hub; propeller blades coupled to the propeller hub; a hub cover coupled to the propeller hub; a hub cover rod coupled to the propeller hub; a conductive portion; a motor configured to rotate the propeller hub, the propeller blades, the hub cover, the hub cover rod, and the conductive portion; and a magnet suspended on the hub cover rod, the magnet being rotatably decoupled from the hub cover rod by a bearing; wherein the magnet is configured to generate a current in the conductive portion when the propeller rotates to manage ice buildup on the surface of the propeller assembly.

[0010] Some embodiments of this disclosure provide a propeller assembly for an aircraft, the propeller assembly including: a rotating portion including: a propeller hub; propeller blades coupled to the propeller hub; a hub cover coupled to the propeller hub; and a conductive portion; a motor configured to rotate the rotating portion; and a magnet configured to remain stationary relative to the motor; wherein the magnet is configured to generate an electric current in the conductive portion as the rotating portion rotates to manage icing on the surface of the rotating portion.

[0011] Some embodiments of this disclosure provide a method for managing icing on an aircraft, the method comprising: determining the icing condition of the aircraft; and performing propeller adjustment based on the icing condition, wherein performing the propeller adjustment includes: adjusting a first propeller parameter of a first group of one or more propellers of the aircraft, and cooperatingly adjusting a second propeller parameter of the first group of one or more propellers of the aircraft, wherein the first propeller parameter and the second propeller parameter are different parameters, each of the first propeller parameter and the second propeller parameter including one of: revolutions per minute (RPM), pitch angle, torque, propeller tilt angle, or propeller angular position about the axis of rotation of the propeller blades of the first group of one or more propellers. Attached Figure Description

[0012] Figure 1A shows an example VTOL aircraft in cruise configuration consistent with embodiments of this disclosure.

[0013] Figure 1B shows an example VTOL aircraft in a lift configuration consistent with embodiments of this disclosure.

[0014] Figure 2 illustrates an example ice management system for a distributed propulsion electric aircraft consistent with embodiments of this disclosure.

[0015] Figure 3A illustrates an example ice management system for a distributed propulsion electric aircraft consistent with embodiments of this disclosure.

[0016] Figure 3B illustrates an example ice management method for a distributed propulsion electric aircraft consistent with embodiments of this disclosure.

[0017] Figures 4A-4D illustrate example ice management cycles consistent with embodiments of this disclosure.

[0018] Figure 5 illustrates an example system for managing asymmetrical ice buildup, consistent with embodiments of this disclosure.

[0019] Figure 6 illustrates an example system for managing asymmetrical ice buildup, consistent with embodiments of this disclosure.

[0020] Figures 7A-7E illustrate an example ice management cycle consistent with embodiments of this disclosure.

[0021] Figures 8A-8C illustrate example systems for managing ice buildup on the surface of electric aircraft, consistent with embodiments of this disclosure.

[0022] Figures 9A-9H illustrate example systems for managing ice buildup on the surface of electric aircraft, consistent with embodiments of this disclosure.

[0023] Figures 10A-10B illustrate example systems for managing ice buildup on the surface of electric aircraft, consistent with embodiments of this disclosure.

[0024] Figure 11 illustrates an example system for managing ice buildup on the surface of an electric aircraft, consistent with embodiments of this disclosure.

[0025] Figure 12 illustrates an example system for determining icing conditions on the propeller of an electric aircraft, consistent with embodiments of this disclosure.

[0026] Figure 13 illustrates an example system for determining icing conditions on the propeller of an electric aircraft, consistent with embodiments of this disclosure.

[0027] Figure 14 illustrates an example system for determining icing conditions on the propeller of an electric aircraft, consistent with embodiments of this disclosure.

[0028] Figure 15 illustrates an example system for managing ice buildup on a propeller hub cover, consistent with embodiments of this disclosure.

[0029] Figure 16 illustrates an example system for managing ice buildup on a propeller hub cover, consistent with embodiments of this disclosure.

[0030] Figures 17A-17B illustrate example systems for managing ice buildup on propeller hub covers or propeller blades, consistent with embodiments of this disclosure.

[0031] Figures 18A-18K illustrate example systems for electrically managing ice buildup on a rotor hub cover or propeller blade, consistent with embodiments of this disclosure. Detailed Implementation

[0032] This disclosure discloses components for aircraft such as vertical takeoff and landing (VTOL) aircraft (e.g., electric vertical takeoff and landing (eVTOL) aircraft). For example, the eVTOL aircraft of this disclosure may be intended for frequent (e.g., more than 50 flights per workday), short-duration flights (e.g., less than 100 miles per flight) over, into, and out of densely populated areas. The aircraft may be designed to carry 4 to 6 passengers or commuters who desire a low-noise and low-vibration experience. Therefore, their components may need to be configured and designed to withstand frequent use without wear, to generate less heat and vibration, and to include mechanisms for effectively controlling and managing the heat or vibration generated by the components. Additionally, it may be anticipated that several of these aircraft will operate close to each other over congested metropolitan areas. Therefore, their components may need to be configured and designed to generate low levels of noise both inside and outside the aircraft, and to be configured and designed with various safety and backup mechanisms. For example, for safety reasons, the aircraft may need to be propelled by a distributed propulsion system to avoid the risk of single points of failure, and they may need to be able to perform routine takeoffs and landings on runways. Furthermore, it may be necessary for aircraft to be able to safely take off and land vertically into spaces that are relatively confined compared to conventional airport runways (e.g., vertical takeoff and landing airports, parking areas, or driveways), while transporting approximately four to six passengers or commuters with baggage. These usage requirements may impose design constraints on aircraft size, weight, and operational efficiency (e.g., drag, energy use), which may affect the design and configuration of aircraft components.

[0033] While the disclosed embodiments can be used in conventional aircraft, they provide new and improved configurations for aircraft components not observed in conventional aircraft, and / or design parameters for components that differ from those in conventional aircraft. These alternative configurations and design parameters, combined with solutions to the shortcomings and challenges of conventional components, result in the various configurations and designs disclosed herein for VTOL or eVTOL aircraft components.

[0034] In some embodiments, the VTOL or eVTOL aircraft of this disclosure may be designed to be capable of both vertical takeoff and landing and conventional takeoff and landing, wherein the distributed electric propulsion system enables vertical flight, forward flight, and transitions. Thrust can be generated by supplying high-voltage electrical power to the electric engines of the distributed electric propulsion system, each of which can convert the high-voltage electrical power into mechanical shaft power to rotate the propeller. Given concerns about safety in passenger transport, the disclosed embodiments implement new and improved safety protocols and system redundancies in the event of failure to minimize any single point of failure in the aircraft propulsion system. Some of the disclosed embodiments also provide new and improved methods to meet aviation and transportation laws and regulations. For example, for certification of flight into known icing (FIKI) conditions, the Federal Aviation Administration (FAA) or its foreign counterparts may require aircraft to reliably prevent or remove icing from their surfaces.

[0035] In some embodiments, the distributed electric propulsion system may comprise twelve electric engines mounted on booms at the front and rear of the aircraft's main wing. The front electric engine can tilt between a horizontally oriented position (e.g., to generate forward thrust) and a vertically oriented position (e.g., to generate vertical lift) during flight. In some embodiments, for vertical takeoff and landing (VTOL) missions, both the front and rear electric engines can provide vertical thrust during takeoff and landing. During the forward flight phase, the front electric engine provides horizontal thrust, while the propeller of the rear electric engine can retract to a fixed position to minimize drag. The rear electric engine can be actively retracted using position monitoring. The transition from vertical to horizontal flight and vice versa can be achieved via a tilting propeller subsystem. The tilting propeller subsystem can redirect thrust between the primary vertical direction during vertical flight mode and the primary horizontal direction during forward flight mode. A variable pitch mechanism can change the total angle of the propeller hub assembly blades of the front electric engine for operation during hovering, transition, and cruise phases.

[0036] In some embodiments, during conventional takeoff and landing (CTOL) missions, the forward electric engine can provide horizontal thrust for wing-borne takeoff, cruise, and landing. In some embodiments, the tail electric engine may not be used to generate thrust during CTOL missions, and the tail propeller may be retracted in place.

[0037] In some embodiments, the electric propulsion system described herein can generate thrust by supplying high-voltage (HV) electricity to an electric engine, which then converts the HV electricity into mechanical shaft power for rotating a propeller. As mentioned 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 can be controlled by torque commands sent by the flight control system (FCS) to each electric engine via a digital communication interface. Embodiments may include a front electric engine capable of changing its orientation or tilt. Additional embodiments include a front engine that may be of clockwise (CW) or counterclockwise (CCW) type. The front electric engine propulsion subsystem may consist of a multi-bladed adjustable-pitch propeller and a variable-pitch subsystem.

[0038] As disclosed herein, an electric motor can include an inverter and a motor; or an inverter, gearbox, and motor spanning various configurations (such as the representative configuration described herein). For example, an electric motor can include an electric motor, gearbox, and inverter, all sharing the same central axis. Alternatively, the central axis can be configured along the axis of the output shaft leading to the aircraft's propeller. In this exemplary configuration, the motor, gearbox, and inverter will all share the output shaft as the central axis and will be oriented circularly around the output shaft. Additional embodiments may include a motor, gearbox, and inverter mounted sequentially together, or a configuration where some components (e.g., the motor and gearbox) are mounted together and another component (e.g., the inverter) is located elsewhere but connected to the electric motor using a wiring system.

[0039] It should be understood that electric motors can generate heat during operation and may include a thermal management system to ensure that components of the electric motor do not fail during operation. In some embodiments, a coolant may be used and circulated in various components of the motor (e.g., inverter, gearbox, or motor), through some components or through all components of the motor, to help manage the heat present in the motor. Additional embodiments may include using air cooling methods to cool the electric motor, or using a mixture of coolant and air to manage the heat generated by the electric motor during operation. In some embodiments, the coolant used may also be the same liquid used as a lubricant in the inverter, gearbox, or motor. For example, liquid or air may be used to cool the inverter, gearbox, and motor, 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 on the inverter, gearbox, and motor, or even a subset of these components.

[0040] In some embodiments, oil can be used as a lubricant in the electric motor and also as a coolant fluid to help manage the heat generated by the engine during operation. Further for this example, varying amounts of oil can be used as both lubricant and coolant fluid in the electric motor, with or without air cooling assistance, such as less than one quart, less than two quarts, or any other amount required to lubricate and cool the electric motor. In some embodiments, alternative coolants, such as ethylene glycol, can be used in addition to oil.

[0041] The inventors have acknowledged certain issues associated with flying into known or potential icing conditions. During flight, icing can occur on the lift and yaw propellers of VTOL aircraft. Icing on aircraft surfaces such as propeller blades, control surfaces, and leading-edge surfaces can degrade aircraft performance and pose safety hazards. Electric aircraft may be particularly prone to propeller blade icing in urban air mobility (UAM) spaces because propellers often operate at lower RPMs 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 can increase the likelihood, rate, or magnitude of icing on propeller blades and other surfaces. Certifying aircraft to fly in icing conditions (including intentional or unintentional entry into known icing conditions) may require anti-icing systems or alternative methods for managing the effects of propeller icing.

[0042] Furthermore, the design of VTOL aircraft may introduce icing problems that conventional aircraft may not experience. For example, some VTOL aircraft may include lift propellers that operate only during lift or hovering phases and can be retracted into a stationary configuration during other situations, such as forward-wing loading. A stationary configuration can lead to asymmetrical icing on the lift propellers. If the lift propellers are activated at that time, this asymmetrical icing can cause adverse propeller imbalance and flight safety risks.

[0043] Additionally, icing can occur on other surfaces during flight, such as air inlets. Icing can also occur on other surfaces, such as wings or control surfaces. Icing can degrade aircraft performance and pose safety hazards. For example, inlet icing can restrict airflow to heat exchangers, such as those located downstream of the inlet, reducing the cooling efficiency of the heat exchangers and potentially causing overheating of electric engines, batteries, or other heat sources. Icing can also affect aircraft performance by reducing lift, increasing weight and drag, and thus requiring greater thrust. FIKI (Fly-in to Known Icing) certification may require anti-icing systems or alternative methods for managing the effects of inlet icing.

[0044] Embodiments of this disclosure can provide systems and methods for detaching or otherwise managing icing on aircraft, such as VTOL aircraft. In this context, management can refer to preventing icing formation and removing existing icing. In some embodiments, management can refer to mitigating problems associated with icing, such as achieving a more balanced icing distribution by forming icing on two opposing propeller blades compared to a lack of icing management. Such management systems can utilize elevated levels of individual motor control available for distributed propulsion architectures in electric aircraft. For example, an icing management cycle can include periodically and alternately adjusting propeller parameters, such as tip Mach number or RPM, on one or more propellers to detach and remove propeller icing. Periodic adjustment of one propeller can be compensated for by corresponding adjustment of the other propeller, allowing icing to be managed without causing unexpected changes in flight trajectory. For example, adjustments can be made in symmetrical pairs such that the increased thrust of the symmetrical propeller pair is balanced on either side of the aircraft. Furthermore, other propellers can 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 zero or substantially close to zero. For example, a first symmetrical outward propeller pair can increase its RPM to a tip Mach number sufficient for anti-icing or de-icing, while a second symmetrical inward propeller pair can reduce its RPM by a corresponding amount. In this way, icing can be removed from the outer propellers without significantly disrupting the flight path or passenger experience. A similar process can then be performed on the inward symmetrical propeller pairs. In some embodiments, the symmetrical propeller pairs can be placed in an extended de-icing mode, rather than performing relatively short-duration periodic adjustments. For example, in some embodiments, the first symmetrical propeller pair can be kept at a high speed to continuously prevent ice formation, while the second symmetrical pair can be completely shut down. This allows some propellers to avoid icing while others can be shut down and left unattended. In some embodiments, the shut-down propellers can be periodically adjusted to prevent excessive icing, and other propellers can be shut down otherwise.

[0045] This system advantageously reduces or eliminates dedicated anti-icing systems such as electric heaters, fluid conduits, thumpers, or other mechanical de-icing devices. This can reduce aircraft cost and weight, while decreasing the number of power-consuming devices and simplifying the control structure, resulting in a simpler, more efficient design with greater fail-safe protection. In some embodiments, the lift propeller can operate in a similar manner to remove accumulated ice.

[0046] Furthermore, the lift propeller can rotate periodically during stationary periods in cruise flight, ensuring that different propeller blades face forward. By distributing the amount of time the blades face forward substantially evenly among each blade, such as in a two-bladed or three-bladed lift propeller, the asymmetry of icing on the blades can be minimized. The periodic rotation of asymmetric icing enables maneuverability, such as transitional and vertical flight after encountering icing, where the propeller needs to be retracted and icing may occur.

[0047] Embodiments of this disclosure may further provide systems for managing icing on surfaces (e.g., air inlets) of VTOL aircraft. For example, an electric aircraft may include an electric engine that is lubricated or cooled via an oil flow path. The oil flow path may span moving parts of the motor assembly (e.g., rotors, gears, etc.) to lubricate and / or cool said parts. The oil flow path may be further configured to flow over or thermally couple with non-moving parts such as inverters to absorb heat from said parts. The oil flow path may pass through a heat exchanger configured to thermally couple with the motor assembly. The heat exchanger may discharge accumulated heat from the air inlet into the airflow. By adding additional segments to the oil flow path, heated oil from the motor assembly can be directed to problem areas prone to icing. For example, it has been found that the lower lip of the air inlet may be more prone to icing than other parts of the inlet (e.g., the upper inlet). Therefore, the oil flow path can bypass, for example, the upper lip of the air inlet, to direct the heated oil toward the problem area without incurring unnecessary adverse consequences in the form of increased weight, conduit pipes, oil volume, oil pump size, pressure loss in the flow path, or the de-icing capacity of the heated oil.

[0048] Embodiments of this disclosure may further provide an electrical system for managing ice buildup. In some embodiments, the ice management system may utilize the electrical or mechanical power of the propeller to wirelessly generate heat in the moving parts of the propeller assembly (e.g., propeller blades or hub caps). For example, in some embodiments, permanent magnets or electromagnets on the stationary portion of the propeller assembly may be configured to induce current flow in the windings or generate eddy current heating in a sheet of conductive material. The current and / or heat may be distributed over the icing-prone surface via, for example, a conductive and / or thermally conductive wiring system. In some embodiments, an AC circuit may be configured to selectively generate current in coils embedded, for example, within the blades or hub cap, which is then distributed via a conductive wiring system.

[0049] Examples of the embodiments are now shown in detail with reference to the accompanying drawings. The following description refers to the accompanying drawings, in which, unless otherwise stated, the same numerals in different figures represent the same or similar elements. The embodiments set forth in the following description of the exemplary embodiments do not represent all embodiments consistent with this disclosure. Instead, they are merely examples of devices and methods consistent with aspects related to the subject matter recited in the appended claims. For example, the description of the VTOL aircraft 100 of Figures 1A and 1B given below is merely an example of the type of distributed propulsion aircraft that can implement the ice management system and methods according to embodiments of this disclosure. For example, in some embodiments, the aircraft may include more or fewer lift propellers or more or fewer tilt propellers, or the lift propellers or the tilt propellers may be installed or operated in a manner different from that shown in Figures 1A and 1B. For example, in some embodiments, the aircraft may include, for example, all lift propellers or all tilt propellers. However, in some embodiments, lift propellers designed for use only in a lift configuration may be tiltable or otherwise movable for retraction in a cruise configuration. In some embodiments, the lift propeller or tilt propeller can be mounted on a boom located in front of or behind the wing, between the canard and aft wing, or mounted on another part of the aircraft, such as the fuselage, strut, or the leading edge, trailing edge, upper surface, lower surface, or tip, tail, etc. of the wing. The ice management system and methods described herein are applicable to many different propeller and aircraft designs, as will be understood by those skilled in the art.

[0050] Figures 1A and 1B respectively illustrate a VTOL aircraft 100 in a cruise configuration and a vertical takeoff, landing, and hovering configuration (also referred to herein as a "lift" configuration) consistent with embodiments of the present disclosure. The aircraft 100 may include a fuselage 102, wings 104 mounted to the fuselage 102, a tail 106, and one or more rear stabilizers 106 mounted to the tail 106 or the rear of the fuselage 102. A plurality of lift propellers 112 may be mounted to the wings 104 and may be configured to provide lift for vertical takeoff, landing, and hovering. A plurality of tilt propellers 114 may be mounted to the wings 104 and may tilt between the cruise and lift configurations, in which the tilt propellers provide forward thrust for horizontal flight, as shown in Figure 1A, and in which the tilt propellers provide a portion of the lift required for vertical takeoff, landing, and hovering, as shown in Figure 1B. As used herein, lift configuration can refer to a tilting propeller orientation in which the tilting propeller thrust primarily provides lift to the aircraft. Cruise configuration can refer to a tilting propeller orientation in which the tilting propeller thrust primarily provides forward thrust to the aircraft. Alternatively, cruise configuration can refer to a configuration in which the lift propeller is retracted.

[0051] In some embodiments, the lift propeller 112 can be configured to provide lift only, with all propulsion provided by the tilt propeller. Thus, the lift propeller 112 can be in a fixed position and can generate thrust only during takeoff, landing, and hovering. Meanwhile, the tilt propellers 114 can be tilted into a lift configuration, where their thrust is vertically pointed to provide additional lift.

[0052] For forward flight, the tilt propeller 114 can tilt from its lift configuration to its cruise configuration. In other words, the pitch angle or tilt angle of the tilt propeller 114 can change from a tilt propeller thrust vertically pointing orientation (to provide lift during vertical takeoff, landing, and hovering) to a tilt propeller thrust horizontally pointing orientation (to provide forward thrust to the aircraft 100). The tilt propeller can tilt about an axis that can be perpendicular to the forward direction of the aircraft 100. When the aircraft 100 is in fully forward flight during cruise configuration, lift can be provided entirely by the wing 104. Meanwhile, the lift propeller 112 can be shut off or can be actively retracted. The blades 120 of the lift propeller 112 can be locked in a low-drag position for aircraft cruise. In some embodiments, the lift propeller 112 may each have two blades 120, which can be locked for cruise in a minimum drag position, in which one blade is directly in front of the other, as shown in FIG1A. 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, the lift propeller 112 may each include, for example, two blades, and the tilt propeller 114 may each include, for example, five blades. In some embodiments, the tilt propeller 114 may have, for example, two to five blades.

[0053] 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), and at least a portion of the lift propeller 112 may be located aft of the wing 104, and at least a portion of the jib propeller 114 may be located forward of the wing 104. In some embodiments, all lift propellers 112 may be located aft of the wing 104, and all jib propellers 114 may be located forward of the wing 104. According to some embodiments, all lift propellers 112 and jib propellers 114 may be mounted to the wing—that is, any lift propeller or jib propeller may not be mounted to the fuselage. In some embodiments, all lift propellers 112 may be located aft of the wing 104, and all jib propellers 114 may be located forward of the wing 104. According to some embodiments, all lift propellers 112 and jib propellers 114 may be positioned inside the wingtip 109.

[0054] In some embodiments, the lift propeller 112 and the jib propeller 114 can be mounted to the wing 104 via a boom 122. The boom 122 can be mounted below the wing 104, on the top of the wing, and / or integrated into the wing profile. In some embodiments, each boom 122 can mount one lift propeller 112 and one jib propeller 114. The lift propeller 112 can be mounted at the rear end of the boom 122, and the jib propeller 114 can be mounted at the front end of the boom 122. In some embodiments, the lift propeller 112 can be mounted in a fixed position on the boom 122. In some embodiments, the jib propeller 114 can be mounted to the front end of the boom 122 via a hinge. The jib propeller 114 can be mounted to the boom 122 such that, in a cruise configuration, the jib propeller 114 is aligned with the body of the boom 122, thereby forming a continuous extension at the front end of the boom 122 that minimizes drag for forward flight.

[0055] In some embodiments, the aircraft 100 may include, for example, a 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 to the upper side of the fuselage 102. According to some embodiments, the wing includes control surfaces such as flaps, ailerons, or flaperones. According to some embodiments, the wing may have curved wingtips 109 to reduce drag during forward flight.

[0056] 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 combinations of rudder-elevator. The wing can 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.

[0057] The aircraft 100 may include at least one door 110 for passenger access. In some embodiments, the door 110 may be located below and in front of the wing 104, as seen in Figures 1A and 1B.

[0058] Further discussion of VTOL aircraft can be found in U.S. Patent Publication No. 2021 / 0362849, the entire contents of which are incorporated herein by reference in their entirety.

[0059] As discussed above, this embodiment mainly addresses the problem of icing on the propellers and surfaces of VTOL aircraft with ice management systems, but it can also be more widely applied to other types of aircraft.

[0060] A. Example Ice Management System Embodiment Figure 2 illustrates an example ice management system 200 consistent with the disclosed embodiments. The ice management system 200 may include, for example, a distributed propulsion electric aircraft (such as the VTOL aircraft 100 in Figures 1A and 1B). The ice management system 200 may include a memory storing instructions, and the processor being configured to execute the instructions to perform various functions of the ice management system. For example, the ice management system 200 may include a flight control system (FCS) or related control architecture. The ice management system 200 may include: an icing condition identification module 201; a condition estimator 202; and a de-icing logic module 203. The icing condition identification module 201 may be configured to determine that an icing condition exists or that the probability of icing has exceeded a predetermined threshold. The icing condition identification module 201 may include, for example, a primary icing detector, a pilot-operated manual switch, or an icing estimator. The icing estimator may include a portion of the FCS configured to determine the probability of an icing condition based on, for example, weather data, geospatial information, information received from authoritative service agencies such as the Federal Aviation Administration (FAA), or aircraft sensor data. In some embodiments, icing conditions may be determined using an accelerometer within an electric motor, propeller, or another module, as discussed further below with respect to Figure 12. In some embodiments, icing conditions may be determined using a motor position sensor within an electric motor, propeller, or another module, as discussed further below with respect to Figures 13 and 14. In some embodiments, the motor position sensor may include, for example, a resolver. The icing condition identification module 201 may be configured to determine icing conditions based on icing condition inputs, such as input signals from the manual switch module 301 or the main icing detector module 302, as discussed below with respect to Figure 3A. Icing conditions include states of at least one of the following: for example, the air surrounding the aircraft contains supercooled liquid water droplets, the average droplet size meets a predetermined size measurement result, the air temperature reaches a predetermined value, ice formation is detected on the aircraft, ice formation is observed on the aircraft, or other similar conditions. Icing condition inputs may indicate that icing conditions have been identified or are suspected. Icing condition inputs may be determined by detection systems on the aircraft, ground-based detection systems, detection systems from weather services, or other third-party detection systems, or a combination of these detection systems. In some embodiments, the icing status input may be based on a primary icing detector. For example, the primary icing detector may include a magnetostrictive icing detector or an optical icing detector. Furthermore, icing conditions may also be determined based on sensors monitoring the aircraft surface, sensors monitoring the aircraft's physical properties, sensors monitoring the surrounding environment, and similar sensors. In some embodiments, an electric engine accelerometer may be used to measure acceleration to determine if there is icing buildup on the propeller.In other disclosed embodiments, icing status input can be determined based on input from the flight control system or the pilot (e.g., via a manual switch). The manual switch can be activated by the pilot monitoring the condition. For example, the pilot can activate the manual switch due to temperature, visible humidity, icing on a reference surface, altitude, or similar characteristics. The manual switch can include a pilot-operable interface such as a button, switch, touchscreen interface, voice command, or any other system for inputting commands by a human user of the electric aircraft.

[0061] When icing is detected, the icing condition identification module 201 can input a signal to the state estimator 202. The state estimator 202 may include one or more processors configured to execute code for determining the aircraft's state. For example, the one or more processors may form part of a flight control system, and the code may include a state estimation algorithm for determining 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's state based on predetermined parameters (e.g., values ​​of airspeed, altitude, roll angle, pitch angle or yaw angle, control surface inclination, etc.) to determine whether performing ice management operations is safe, feasible, or otherwise acceptable. These values ​​may be determined, for example, by detection or by inference from flight control commands. For example, the roll angle may be determined based on sensors configured to detect the roll angle, or it may be inferred based on flight control commands used to maneuver the aircraft into a roll angle. The state estimator 202 can provide an estimate of the aircraft's internal state based on measurements of the aircraft's inputs and outputs. In some embodiments, the state estimator 202 may be configured to perform aircraft integrity checks and isolate or limit the functionality of ice management operations, such that operations are performed only when operations are acceptable, or only to an extent or degree acceptable based on the current aircraft state. For example, the state estimator 202 may limit ice management operations to when the aircraft is within a specific range, such as yaw angle, pitch angle, or roll angle, for example, + / - 5 degrees, + / - 10 degrees, + / - 15 degrees, etc. In some embodiments, the range of angles considered acceptable may vary with other relevant factors, such as airspeed, roll angle, 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 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 confirm that all necessary propellers for performing ice management are operable and effective.

[0062] The aircraft state can be determined based on parameters such as aircraft speed, aircraft mode, aircraft propeller angle, external conditions, or similar parameters. In some embodiments, propeller adjustment can be performed only when the aircraft state meets predefined parameters (e.g., control margin state, current roll angle, load factor, vertical airspeed and command airspeed, altitude, propulsion system integrity, signal integrity, flight mode, etc.). In some embodiments, the ice management system 200 may include a processor configured to determine the aircraft state based on the state estimator 202.

[0063] State estimator 202 can be configured to input commands to de-icing logic module 203 based on, for example, determined aircraft state and icing condition inputs. De-icing logic module 203 can be configured to generate actuator commands to induce one or more ice management cycles. For example, actuator commands may include command signals for actuators, electric motors, or other control devices for adjusting one or more parameters, such as propeller pitch angle, motor (RPM), or tilt actuator (tilt angle of a tilt propeller system). As discussed further below, adjusting these parameters using actuator commands can induce ice management cycles, and the specific actuator command selected may depend on the type of ice management operation performed. For example, in some embodiments, the flight control system may access libraries, reference tables, or other data structures, or may use models, to define a correspondence between one or more parameters among various propeller adjustment parameters and multiple actuator commands. This correspondence can then be used to generate multiple actuator commands to implement ice management cycles. Ice management cycles may include, for example, de-icing, anti-icing, or ice compensation. De-icing may involve removing existing ice from the aircraft. Anti-icing can include preventing ice formation on aircraft. Ice compensation can include reducing or offsetting ice formation on aircraft. Ice management cycles can continue for a predetermined time, or for a time interval that varies with each cycle, or continue until a predetermined event occurs, such as until predetermined parameters are met.

[0064] Figure 3A illustrates an example ice management system 300 consistent with the disclosed embodiments. The ice management system 300 may include, for example, a portion of a distributed propulsion electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). In some embodiments, the ice management system 300 may correspond to the ice management system 200 of Figure 2. In some embodiments, the ice management system 300 may include a portion of a flight control system (FCS) or an associated control architecture. The ice management system may include: a manual switch module 301; a main icing detector module 302; an icing condition identification module 303 configured to output a valid icing condition 310 or an invalid icing condition 311; a state estimator 304 configured to output a valid aircraft state input 305 or an invalid aircraft state 308; an enable regulation logic module 306 configured to output an actuator command 307; and a regulation logic disable module 309.

[0065] The manual switch module 301 may include a manual on / off switch as discussed above. The manual switch can be activated 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 zero degrees Celsius. The manual switch module 301 can determine the icing condition input to the icing condition identification module 303.

[0066] The main icing detector module 302 may include, for example, a main icing detector. For example, the main icing detector may include a magnetostrictive icing detector, an optical icing detector, or any detector that can be used to indicate icing conditions.

[0067] The icing condition identification module 303 can determine the icing condition based on icing condition inputs from, for example, the manual switch module 301 or the main icing detector module 302, as discussed above. In some embodiments, the icing condition identification module 303 can output a valid icing condition 310. A valid icing condition can indicate the presence of icing, while an invalid icing condition can indicate the absence of icing. Different "valid" icing conditions can exist for different types or severityes of icing, and the ice management operations for different types or severityes of icing can also differ. The valid icing condition 310 can be input to the state estimator 304. In some embodiments, the icing condition identification module 303 can output an invalid icing condition 311, where the invalid icing condition 311 is an input to the regulation logic disable module 309.

[0068] The state estimator 304 can be configured to receive a valid icing condition input 310 from the icing condition identification module 303 and output a valid aircraft state 305 to the enable regulation logic module 306. A valid aircraft state 305 indicates that the aircraft is in an acceptable flight state for performing propeller regulation for ice management, while an invalid aircraft state 308 indicates that the aircraft is not in an acceptable flight state for performing propeller regulation for ice management. In some embodiments, the state estimator 304 can be configured to receive a valid icing condition 310 from the icing condition identification module 303 and output an invalid aircraft state 308 to the regulation logic disable module 309.

[0069] The enable adjustment logic module 306 can be configured to receive valid aircraft state input 305 from the state estimator 304 and determine appropriate propeller adjustment parameters based on information such as aircraft state or icing conditions. Propeller adjustment parameters may include, for example, status, state, rate, angle, speed, mode, or other adjustable aircraft characteristics. For example, propeller adjustment parameters may be tip Mach number, revolutions per minute (RPM), collective pitch angle, pitch angle, torque, or propeller tilt angle. The enable adjustment logic module 306 can generate multiple actuator commands 307 corresponding to the propeller adjustment parameters. Actuator commands 307 can be sent, for example, to the aircraft's actuators, such as electric engines or control surfaces, via the flight control system. In some embodiments, the flight control system can be configured to generate multiple actuator commands in repeating time intervals. The repeating time intervals may include periodically performing propeller adjustments over a predetermined duration. For example, when the propeller control parameters are propeller speed parameters, such as tip Mach number (the ratio of the speed of the propeller tip to the speed of sound in the surrounding air) or revolutions per minute (RPM), ice management operations may include, for example, increasing the RPM every 15 seconds, every 2 minutes, every 5 minutes for 2 seconds, or any other suitable combination of frequency and duration appropriate to a particular aircraft type, aircraft condition, and icing condition. The propeller control parameters may be determined based on effective icing condition 310 and effective aircraft condition 305.

[0070] The regulation logic disable module 309 can be configured to disable propeller regulation logic when it is determined that the propeller regulation is, for example, unsafe or unnecessary. For example, the regulation logic disable module 309 can receive an invalid icing condition input 311 from the icing condition identification module 303, indicating that the propeller regulation is unnecessary. Alternatively or additionally, the regulation logic disable module 309 can receive an invalid aircraft state input 308 from the state estimator 304, indicating that the propeller regulation is unsafe or undesirable. The regulation logic disable module 309 can be configured to prevent the execution of immediate ice management operations while the ice management system 300 continues to operate.

[0071] Figure 3B illustrates an example de-icing method 350 consistent with embodiments of the present disclosure. Method 350 can be performed, for example, in a flight control system including the ice management system 200 or 300 of Figure 2 or Figure 3A. At step 351, the ice management system can determine that icing is present. As discussed throughout the present disclosure, icing conditions can be determined based on, for example, ice detection, or they can be inferred based on other factors such as the likelihood of icing in a given environment.

[0072] At step 352, the ice management system can perform propeller adjustments based on the determined icing conditions. For example, a specific propeller adjustment can be selected based on factors such as the nature of the determined icing conditions or the flight characteristics at the time of the determined icing conditions to generate a first de-icing cycle. For example, if it is determined that rapidly changing the propeller pitch or increasing the engine RPM will effectively manage the determined icing conditions and can be safely performed under the current flight characteristics, this propeller adjustment can be selected.

[0073] As discussed further below, performing propeller adjustments may include step 353, which initiates a first icing management cycle, and step 354, which initiates a second icing management cycle. The first icing management cycle may include adjusting one or more propellers in a first group (such as a first propeller or a first symmetrical propeller pair), while other propellers remain constant or perform compensating adjustments to ensure flight remains undisturbed. The second icing management cycle may include adjusting one or more propellers in a second group (such as a second propeller or a second symmetrical propeller pair), while other propellers remain constant or perform compensating adjustments. The first and second icing management cycles may occur in different time intervals. In this way, the individual propellers can “take turns” managing icing conditions without causing serious disruption to flight.

[0074] Figures 4A-4D illustrate example ice management cycles 402-404 and 410-419 according to the disclosed embodiments, relative to example normal flight condition 401. The ice management cycles can be performed according to, for example, the ice management system 200 or 300 of Figures 2 and 3A. Arrow 440 in Figures 4A-4D can represent the relative magnitude of adjustment parameters, such as propeller speed. For example, as shown in the normal condition of forward flight 401 where the ice management cycle does not occur, the propeller speeds of each tilt propeller can be equal, while other configurations can exhibit magnitudes higher or lower than those seen in the normal condition at 401. For example, some propellers can increase their propeller speeds to higher speeds than shown in normal condition 401 to allow ice to detach, while other propellers can compensate for any changes in thrust by decreasing their propeller speeds to lower speeds than shown in normal condition 401. In some embodiments, multiple actuator commands may be executed to induce a first ice management cycle 402 in a first symmetrical propeller pair 405 of an electric aircraft and a second ice management cycle 403 in a second symmetrical propeller pair 406 of an electric aircraft, wherein the first ice management cycle 402 occurs in a first time interval different from a second time interval of the second ice management cycle 403. The symmetrical propeller pair may comprise a symmetrical tilt propeller or a lift propeller pair. In some embodiments, the symmetrical propeller pair may be symmetrical about the body of the aircraft. In some embodiments, the first symmetrical propeller pair 405 and the second symmetrical propeller pair 406 may comprise a tilt propeller pair. In some embodiments, the first symmetrical propeller pair 405 may comprise 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 laterally opposite sides of the aircraft body, such as sides located on opposite wings. In some embodiments, the second symmetrical propeller pair 406 may include a third propeller located on a first side of the aircraft body, extending inward from the first propeller, and a fourth propeller located on a second side of the aircraft body, extending inward from the second propeller.

[0075] The disclosed embodiments include management cycles occurring in different time intervals. In some embodiments, the first management cycle 402 may occur in a different time interval than the second management cycle 403. For example, different time intervals may include multiple different non-overlapping time intervals, or may represent time intervals with different start or end points but some overlap. For example, one propeller pair may accelerate while another propeller pair slows down, causing their ice management cycles to overlap. In some embodiments, multiple actuator commands 307 may be configured to cause the first ice management cycle 402 and the second ice management cycle 403 in non-overlapping time intervals. The different first and second time intervals may include different start and stop times, different ice management cycle durations, different time spans, different time periods, etc.

[0076] The disclosed embodiments include additional ice management cycles corresponding to additional symmetrical propeller pairs. In some embodiments, multiple actuator commands are further configured to induce a third ice management cycle 404 in a third symmetrical propeller pair 407 of the electric aircraft, the third ice management cycle 404 occurring in a third time interval, distinct from the first and second time intervals. In some embodiments, the third symmetrical propeller pair 407 may include a fifth propeller located on a first side of the aircraft body between the first and third propellers, and a sixth propeller located on a second side of the aircraft body between the second and fourth propellers. It should be understood that the ice management cycles are identified as first, second, and third for distinction purposes and do not indicate a specific order.

[0077] The disclosed embodiments involve changing the propeller adjustment values ​​of a set of propellers by predetermined values. For example, propeller adjustment parameters may include RPM, and during a first icing management cycle 402, the RPM of a first symmetrical propeller pair 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 for the propeller blades (e.g., 0.5, 0.6, or higher) or another value sufficient to eliminate or prevent icing. For example, under normal flight conditions, a typical eVTOL or another distributed electric propulsion aircraft may operate at, for example, a low Mach number of about 0.3 or 0.4 to avoid generating excessive noise. However, according to embodiments of this disclosure, the RPM of a propeller pair may be temporarily adjusted to a higher value. For example, when only one propeller pair is adjusted at a time, icing can be managed without generating unacceptable levels of noise or severely interfering with flight characteristics. In some embodiments, adjustment may be performed on more than one pair but fewer than all pairs. In some embodiments, all propeller pairs configured for forward flight may be adjusted simultaneously for a short period, but this can increase noise or interfere with flight characteristics. In some embodiments, the adjustment can be compensated for by operation in other propellers or by actuating flight control surfaces.

[0078] In some embodiments, the RPM of the first symmetrical propeller pair 405 may be increased by at least, for example, 50% or 80%. In some embodiments, the RPM of the first symmetrical propeller pair 405 may be increased to at least, for example, 50% or 80% of the maximum available RPM during a first time interval. In some embodiments, other symmetrical propellers may reduce their RPM to compensate for the increased RPM of the first symmetrical propeller pair during the first ice management cycle 402, as indicated by the relatively short arrows at 406 and 407. In some embodiments, other compensation operations may be performed, such as actuating control surfaces, so that an ice management cycle can be performed without any substantial disruption to the flight path or passenger experience.

[0079] In some embodiments, propeller adjustment parameters may include the pitch angle, and during the first ice management cycle 402, the pitch angle of the first symmetrical propeller pair 405 may change by at least, for example, 5 degrees, 10 degrees, or 20 degrees within a first time interval. For example, the pitch angle may be changed to induce higher aerodynamic blade loads. For instance, in some embodiments, the pitch angle may be changed from a first pitch angle to a second pitch angle, changing by, for example, + / - 5 degrees, for a period of time, for example, more than 10 seconds (such as about 30 seconds or longer). In some embodiments, the first ice management cycle 402 may include changing the pitch angle of the first symmetrical propeller pair 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 may include any other duration. Rapidly changing the pitch angle may loosen ice or expose it to various airflows.

[0080] In some embodiments, propeller adjustment parameters may include torque, and the first ice management cycle 402 may include changing the torque value of the first symmetrical propeller pair 405 by a predetermined amount during a first time interval. In some embodiments, the ice management cycle may include rapid back-and-forth acceleration to shake ice buildup off the propeller blades. For example, an electric engine in a distributed propulsion system can reverse direction, brake the propeller, or otherwise decelerate the propeller, thereby causing such rapid changes. For example, in some embodiments, such braking or deceleration may include rotating the propeller in a single direction while intermittently decelerating and accelerating to cause a series of rapid start-stop motions that dislodge the ice, while in some embodiments, the direction of rotation may be periodically reversed. In some embodiments, the electric engine may use regenerative braking to harvest energy from the propeller while also implementing negative acceleration to manage the ice. In some embodiments, the first ice management cycle 402 may include increasing the torque of the first symmetrical propeller pair 405 by at least, for example, 50% or 80%. In some embodiments, the first ice management cycle 402 may include, during a first time interval, increasing the torque of the first symmetrical propeller pair 405 from an initial torque value to, for example, 50% or 80% of the maximum torque, and decreasing the torque of the first symmetrical propeller pair 405 to, for example, below 50%, 30%, 20%, or 10% of the maximum torque. For example, the initial torque value may be the torque value applied at the start of the ice management cycle before changing the torque value.

[0081] In some embodiments, the propeller adjustment parameter may be the propeller tilt angle, and the first ice management cycle 402 may include changing the propeller tilt angle of the first symmetrical propeller pair 405 by a predetermined amount during a first time interval, such as changing it by at least 5 degrees, 10 degrees, 20 degrees, or 30 degrees. The tilt angle may be changed, for example, to generate edge or axial gas flow above the propeller blades. This may be beneficial for de-icing trajectory optimization. In some embodiments, the first ice management cycle 402 further includes increasing the second RPM of the second symmetrical propeller pair 406 during the first time interval, or performing another compensation operation discussed above. Alternatively, the tilt angle adjustment may serve to compensate for another de-icing cycle, or two complementary de-icing cycles may be performed together. For example, changing the tilt angle can produce a thrust vector with a vertical component, which may help compensate for reduced lift due to simultaneous adjustments occurring in the same or another propeller pair. Some examples of such combined propeller adjustment parameters are shown at Figure 4D.

[0082] Additional ice management cycles can be performed on other symmetrical propeller pairs in a manner corresponding to the description of the first symmetrical propeller pair 405. Furthermore, although the ice management cycles are described with respect to the tilt propeller, the embodiments of this disclosure are not limited thereto. For example, in some embodiments, the lift propeller can be adjusted according to the propeller adjustment parameters described above, instead of the tilt propeller or in addition to the tilt propeller.

[0083] Furthermore, the adjustments do not need to be performed in symmetrical pairs. Figure 4B illustrates another set of ice management cycles 410-413 consistent with embodiments of this disclosure. As shown in Figure 4B, the adjustment cycles can occur in symmetrical sets rather than symmetrical pairs. That is, the net thrust or other parameters of the first set 408 propellers on the first side of the aircraft body can be substantially equal to the second net thrust or other parameters of the second set 409 propellers on the second side of the aircraft body. At the same time, the magnitudes of the individual adjustment parameters on the symmetrical pair may not be equal. An example of such adjustment is shown in ice management cycles 410-413.

[0084] As seen in ice management cycle 410, the middle propeller of the first group 408 can be adjusted to a first RPM (or other adjustment) value, and the innermost propeller of the second group 409 can be adjusted to a second higher RPM (or other adjustment) value. Because the two adjusted propellers are located at different distances from the center of the aircraft, for a given amount of thrust, the two adjusted propellers can apply different torques about the vertical (outside the page in Figure 4B) axis. By adjusting the two propellers by different amounts, the net effect of the first group 408 propellers and the second group 409 propellers can be balanced. Ice management cycle 411 shows the opposite adjustment to that made in ice management cycle 410, where the middle propeller of the second group 409 can be adjusted to the first RPM value, and the innermost propeller of the first group 408 can be adjusted to a second higher RPM value.

[0085] As seen in ice management cycle 412, the adjustment of a single large propeller, such as the outermost propeller of the first group 408, can be offset by the uniform propeller adjustment of all propellers in the second group 409. This allows the propellers of the first group 408 and the second group 409 to balance each other while minimizing the number of propellers requiring high-amplitude adjustments. Ice management cycle 413 shows the opposite adjustment to ice management cycle 412, where the outermost propeller of the second group 409 can be offset by the uniform propeller adjustment of all propellers in the first group 408.

[0086] In some embodiments, as discussed above, it may be preferable to regulate the propeller with symmetrical groups rather than symmetrical pairs, because a more complex regulation distribution can be tailored to allow regulation to be performed during aircraft states that could otherwise be considered ineffective or suboptimal, such as during roll. In some embodiments, regulation may be fundamentally non-symmetrical to allow regulation to be performed in such aircraft states. For example, in some embodiments, an aircraft state / evaluation system (e.g., 304 in FIG. 3A) may determine that the state is ineffective for symmetrical pair regulation, but may still determine that the aircraft state is effective for alternative regulation such as symmetrical group regulation or asymmetrical regulation.

[0087] Figure 4C illustrates another set of ice management cycles 414-417 consistent with embodiments of this disclosure. Instead of performing relatively short-duration periodic adjustments, the symmetrical propeller pairs can be placed in extended de-icing modes. For example, in some embodiments, the first symmetrical propeller pair can be kept at a high speed to continuously prevent ice formation, while the second symmetrical pair can be completely shut down. This allows some symmetrical propeller pairs (such as propeller pairs 405 and 407 seen in management cycle 414) to completely avoid icing by continuously operating at levels that prevent or reduce icing. Meanwhile, other propeller pairs (such as propeller pair 406 seen in management cycle 414) can be shut down and ignored. The same applies to ice management cycle 415, in which propeller pairs 405 and 406 can operate continuously at levels that prevent or reduce icing, while propeller pair 407 can be shut down. Alternatively, as shown in ice management cycle 417, propeller pairs 405 and 406 can operate continuously at two different levels to prevent or reduce icing, while propeller pair 407 can be shut off.

[0088] In some embodiments, a single propeller pair may be operational while other propeller pairs are off. For example, in ice management cycle 416, propeller pair 406 may be continuously operational, while propeller pairs 405 and 407 are both off. In some embodiments, the propellers off in ice management cycles 414-417 may be periodically adjusted according to the embodiments discussed above to prevent excessive icing and may be off at other times. For example, when the propeller pair is a lift propeller pair, the lift propellers may be off for an extended period when retracted in cruise configuration. Thus, in some embodiments, propeller adjustment may include periodically spinning one or more lift propellers while in cruise configuration and then returning said one or more lift propellers to a stationary retracted position. Similarly, when the propellers include off tilt propellers as discussed above, the propellers may be periodically adjusted to prevent excessive or unbalanced icing.

[0089] Ice management cycles 414-417 can concentrate RPM and engine heat generation on a small number of propellers, which can be advantageous when used in conjunction with other ice management techniques, such as transferring engine heat to icing-prone surfaces or generating electrical heating through propeller motion, both of which are discussed below. Furthermore, although the accompanying drawings show three pairs of swashplate propellers and three pairs of lift propellers, the embodiments are not limited thereto. Additionally, while some adjustment parameters are tailored to specific propeller types (such as swashplates, lift propellers, and variable pitch propellers), others are common to many types. Therefore, any suitable number or type of propellers can be used in distributed propulsion systems (such as VTOL or CTOL aircraft) to practice the ice management cycles according to embodiments of this disclosure.

[0090] Similarly, as discussed above, one or more propeller adjustment parameters can be used together to achieve combined ice management effects or provide compensatory regulation. Figure 4D illustrates example ice management cycles 418 and 419 relative to a normal operating period 401, during which the propeller is positioned with the flow oriented in the primary axial direction. Arrow 440 in Figure 4D can indicate the relative magnitude of adjustment parameters, such as propeller speed. For example, de-icing cycle 418 may include tilting one or more tilt propellers to a desired tilt angle to induce edge flow along the propeller blades. Simultaneously, as indicated by arrow 440a, the RPM on the same one or more tilt propellers can be increased to perform multiple de-icing cycles as discussed above together. Alternatively or additionally, other propeller adjustment parameters, such as pitch or propeller torque, can be performed simultaneously. Additionally, one or more additional tilt propellers can be adjusted to compensate for these propeller adjustments. For example, the RPM of another one or more tilt propellers can be decreased, as indicated by the shorter arrow 440b. Furthermore, as shown in ice management cycle 419, multiple propeller adjustment parameters can be used to simultaneously adjust all propellers to eliminate ice while maintaining the desired trajectory. For example, as shown, all tilt propellers are tilted relative to their forward orientation compared to normal operating period 401.

[0091] B. Example Embodiments for Managing Asymmetric Icing Asymmetric icing can occur in a propeller that is stationary during flight. For example, when a lift propeller remains stationary during cruise flight, more ice can form on the forward-facing blades than on the rearward-facing blades, resulting in asymmetric ice buildup. If asymmetric icing exists on a stationary propeller and then the propeller is activated, the asymmetric icing can create adverse propeller imbalance and flight safety risks. The disclosed embodiments include an ice management cycle in which a stationary propeller (such as a lift propeller) rotates periodically to distribute and / or reduce (e.g., minimize) the icing.

[0092] Figure 5 illustrates an example system 500 for managing asymmetric icing, consistent with embodiments of this disclosure. The ice management system 500 may include, for example, a part of a distributed propulsion electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The ice management system 500 may be similar to the ice management system 200 of Figure 2, but may be adapted for ice management of lift propellers. For example, the ice management system 500 may include part of a flight control system (FCS) or related 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 of Figures 2-3. The ice management system 500 may include: an icing condition identification module 501; a state estimator 502; and a de-icing logic module 503. The icing condition identification module 501 may include a main icing detector or a manual switch. The icing condition identification module 501 may be configured to determine the icing condition based on icing condition input. The state estimator 502 may be configured to determine the aircraft state.

[0093] The de-icing logic module 503 can be configured to generate actuator commands to induce multiple ice management cycles. The de-icing logic module 503 can also send actuator commands 307 to cause the propeller to rotate periodically. For example, for the two-bladed configuration shown in the figure, the de-icing logic module 503 can send actuator commands 307 to cause the propeller to rotate approximately 180 degrees. In some embodiments, such as a three-bladed lift propeller, the de-icing logic module 503 can send actuator commands 307 to cause the propeller to rotate approximately 60, 90, or 120 degrees. Generally, the lift propeller can rotate periodically during stationary periods in cruise flight, with different lift propeller blades facing forward, for example, in some embodiments, multiples of 30 degrees for propellers with, for example, 2, 3, 4, or 6 blades. By distributing the amount of time facing forward substantially evenly among each blade of, for example, a two-bladed lift propeller, a three-bladed lift propeller, etc., the asymmetry of icing on the blades can be minimized. Alternatively, at least some propeller blades may rotate slowly and continuously to distribute the ice buildup evenly. For example, in some embodiments, propeller blades may rotate between 6 RPM and 120 RPM or slower than other propeller blades.

[0094] Figure 6 illustrates an example 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 vehicle (VTOL aircraft 100 as shown in Figures 1A-1B). The ice management system 600 may be similar to the ice management system 300 of Figure 3A, but may be adapted for ice management of lift propellers. The ice management system 600 may be part of a flight control system (FCS) or associated control architecture. The ice management system may include: a manual switch module 601; a main icing detector module 602; an icing condition identification module 603 configured to output a valid icing condition 610 or an invalid icing condition 611; a state estimator 604; a valid aircraft state input 605 configured to output a valid aircraft state input 605 or an invalid aircraft state 608; an enable regulation logic module 606 configured to output actuator commands 607; and a regulation logic disable module 609.

[0095] The manual switch module 601 may include a manual on / off switch. The manual switch can be activated by a pilot monitoring the situation. The manual switch module 601 can determine the icing status input to the icing status identification module 603 based on the state of the manual switch.

[0096] The main icing detector module 602 may include a main icing detector, such as a magnetostrictive icing detector or an optical icing detector. The icing detector module 602 can determine the icing state input to the icing state recognition module 603.

[0097] The icing condition identification module 603 can determine the icing condition based on the icing condition input from the manual switch module 601 or the main icing detector module 602.

[0098] The state estimator 604 can be configured to take into input a valid icing condition 610 from the icing condition identification module 603 and output a valid aircraft state input 605 to the enable adjustment logic module 606.

[0099] The enable regulation logic module 606 can determine appropriate propeller regulation parameters based on information such as aircraft status or icing conditions, and generate multiple actuator commands 607 corresponding to the propeller regulation parameters. Actuator commands 607 can be sent to aircraft actuators, such as electric engines or control surfaces, for example, via the flight control system. Actuator commands 607 can include commands for initiating icing management cycles and, in the case of asymmetric icing embodiments.

[0100] The regulation logic disable module 609 can be configured to input invalid icing condition 611, invalid aircraft condition 608, or both invalid icing condition 611 and invalid aircraft condition 608. The regulation logic disable module 609 continuously monitors the icing condition and aircraft condition.

[0101] Figures 7A-7E illustrate example ice management cycles, such as the first, second, and third lift ice management cycles 702-704, consistent with embodiments of the present disclosure and relative to normal operating time period 701. Unlike the conditioning cycles of Figures 4A-4D that can be performed on the lift propeller as discussed above, lift ice management cycles 702-704 can be designed to manage asymmetrical icing. During cruise flight, for example when the lift propeller remains stationary in the retracted position for an extended period, asymmetrical icing may occur because one blade faces forward toward the airflow while the other blades face away from or at an angle to the airflow. Lift ice management cycles 702-704 can be performed using, for example, ice management systems 500 and 600 of Figures 5-6. The embodiment in Figure 7A illustrates an example in which lift propeller conditioning is performed during normal tilt propeller operation, while Figures 7B and 7C illustrate the same operation performed in parallel with tilt propeller conditioning. Figures 7D and 7E show example lift propellers in various angular positions, for example, to provide uniform ice accumulation.

[0102] In some embodiments, the first lift ice management cycle 702 may include rotating the first symmetrical outermost pair of lift propellers 705 between a first angular position and a second angular position. For example, the first angular position may correspond to a first propeller blade on each pair substantially pointing forward of the aircraft, and the second angular position may correspond to a second propeller blade on each pair substantially pointing forward of the aircraft. The second propeller blades may be adjacent propeller blades in the direction of rotation, or there may be intermediate blades. For example, for propellers having 2, 3, 4, or 5 blades respectively, the first angular position may be offset relative to the second angular position by, for example, an integer multiple of about 180 degrees, 60 degrees, 45 degrees, or 36 degrees. Examples of four-bladed and two-bladed configurations are shown at Figures 7D and 7E, respectively. However, in some embodiments, the angular spacing between each pair of adjacent propeller blades may be non-uniform. It should be understood that the angular spacing described above is merely an example, and the chosen angular rotation may depend on, for example, the propeller blade spacing and curvature. Similar to the first lift ice management cycle 702, the second lift ice management cycle 703 may include rotating the middle second symmetrical lift propeller pair 706 between a first angular position and a second angular position. The third lift ice management cycle 704 may include rotating the innermost third symmetrical lift propeller pair 707 between a first angular position and a second angular position. In some embodiments, more than one symmetrical lift propeller pair may rotate simultaneously.

[0103] In some embodiments, ice management can be performed at, for example, the propeller shaft, hub, blades, or other components using an oscillator coupled to the propeller. The oscillator can be configured to cause the lift propeller to vibrate at a selected resonant frequency of the propeller blades. This can cause the propeller blades to vibrate with a force sufficient to break up the ice that has formed on them. While this can be an advantageous approach for managing stationary propellers such as lift engines, it should be understood that in some embodiments, the oscillator can be applied to a swashplate.

[0104] As shown in Figure 7A, the symmetrical tilt propeller pair 405-407 can continue normal operation while the lift propeller rotates between different angular positions, similar to the normal operation period 401 shown in Figure 4A. However, in some embodiments, while the lift propeller is being adjusted, multiple actuator commands 607 can adjust the symmetrical tilt propeller pair 405, 406, or 407 to manage ice or counteract disturbances caused by the adjustment of the lift propeller. For example, as seen in Figure 7B, multiple actuator commands 607 can induce a first lift propeller ice management cycle 702, while simultaneously executing in parallel, for example, the first ice management cycle 402 discussed relative to Figure 4A. Similarly, a second lift propeller ice management cycle 703 can be executed, while simultaneously executing in parallel, for example, the second ice management cycle 403 discussed relative to Figure 4A. Further, a third lift propeller ice management cycle 704 can be executed, while simultaneously executing in parallel, for example, the third ice management cycle 404 discussed relative to Figure 4A. Executing these parallel cycles allows adjustment of the tilt propeller located directly in front of the corresponding adjusted lift propeller.

[0105] Alternatively, as shown in FIG7C, in some embodiments, the yaw propeller adjustment can be spatially offset relative to the lift propeller adjustment, such that the adjusted yaw propeller is not always directly in front of the adjusted lift propeller. For example, a first lift ice management cycle 702 can be performed simultaneously, for example, a third ice management cycle 404 discussed relative to FIG4A. Further, a third lift ice management cycle 704 can be performed simultaneously, for example, a first ice management cycle 402 discussed relative to FIG4A. Even so, the intermediate lift propeller 706 and yaw propeller 406 can still be adjusted in parallel. For example, a second lift ice management cycle 703 can be performed simultaneously, for example, a second ice management cycle 403 performed in parallel in the same manner as discussed above relative to FIG7B.

[0106] Figures 7D and 7E illustrate example configurations and angular positions for ice management on a lift propeller 712 consistent with embodiments of the present disclosure. The lift propeller 712 may include a plurality of propeller blades 730. For example, as shown in Figure 7D, the lift propeller 712 may include four blades, while in Figure 7E, the lift propeller 712 may include two blades. As discussed above, other numbers of blades are also possible, and the embodiments described herein are not limited to the configurations shown. The propeller 712 may rotate periodically in a continuous or alternating direction so that the individual blade surfaces are exposed to the forward airflow at different angles of incidence. For example, the propeller 712 may initially retract into a first angular position, where the leading edge 730a is exposed to the forward airflow 740. In this position, the leading edge 730a will accumulate more ice than the trailing edge 730b. Therefore, propeller 712 can be actuated to a second angular position (e.g., approximately 90 degrees from the first angular position discussed above), such that trailing edge 730b is now exposed to the forward airflow 740. This process can be repeated so that similar amounts of ice accumulate on all leading edges 730a and trailing edges 730b, as discussed above. For example, in a four-bladed lift propeller, the propeller can be rotated so that the rearward-facing blades become forward-facing blades. For example, the difference between the first and second angular positions can be, for example, approximately 180 degrees or 270 degrees. In some embodiments, these angular position movements may be accompanied by intermittent de-icing operations, such as spinning blade 730, vibrating the blades, heating the blades, etc., to remove ice.

[0107] As shown in Figure 7E for, for example, a two-bladed lift propeller 712, the difference between the first angular position and the second angular position can be, for example, 180 degrees, as discussed above. For example, the propeller 712 can initially be retracted to the first angular position, where the tip 731a of the first blade is exposed to the forward airflow. In this position, the tip 731a of the first blade will accumulate more ice than the tip 731b of the second blade. Therefore, the propeller 712 can be actuated to the second angular position (e.g., approximately 180 degrees from the first angular position discussed above), so that the tip 731b of the second blade is now exposed to the forward airflow. Alternatively or additionally, as shown on the right side of Figure 7E, the two-bladed propeller can be angularly positioned relative to the forward direction of motion, such that either the leading edge 730a or the trailing edge 730b is exposed to the forward airflow.

[0108] C. Example Embodiment for Managing Ice Accumulation on Air Inlets and Other Surfaces Figures 8A-8C illustrate example propeller systems 800A-800C consistent with the disclosed embodiments, configured to manage ice accumulation on the surfaces of an electric aircraft. Propeller systems 800A-800C may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). Propeller systems 800A-800C may include: a propeller 801, a motor assembly 802, a heat exchanger 803, an oil flow path 804 including a first section 811 and a second section 812, a pump 840, and a hull 805. Motor assembly 802 may include various subsystems, such as a motor 835, a gearbox 836, or an inverter 837. While the components of the motor assembly are shown in a certain order, the embodiments disclosed are not limited thereto. For example, in some embodiments, the gearbox 836 may be positioned closer to the propeller 801 than the motor 835, or the inverter 837 may be located in another position.

[0109] The disclosed embodiments include a motor assembly 802 coupled to a propeller 801. An oil flow path 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, wherein the nacelle 805 may include an air inlet 806. In some embodiments, mechanical coupling to the motor assembly may include a direct connection to the motor assembly. The oil flow path 804 may traverse or thermally couple to components within a subsystem of the motor assembly 802 to lubricate and / or cool the components. It should be understood that the oil flow 804 is shown in a highly schematic manner to indicate that in some embodiments, the flow path 804 may reach or be in thermal communication with each subsystem of the motor assembly 802. The oil flow path should not necessarily be interpreted as a loop or a single continuous flow in series. For example, in some embodiments, the oil can be separated and distributed to individual components to lubricate and collect heat from them, and then collected at an oil collector (not shown, discussed below with respect to FIG. 15), and the oil can be recirculated, for example, by a pump 840. Pump 840 may, for example, be a gear-driven pump. Pump 840 may be coupled to a gearbox 836 such that it operates when the motor assembly 802 is active. Alternatively, pump 840 may be a separate pump that can be powered, for example, by an inverter 837. In some embodiments, oil can be forced through an oil flow path 804 without using a dedicated pump.

[0110] Oil flow path 804 can pass through heat exchanger 803 to thermally couple heat exchanger 803 to motor assembly 802. For example, heat exchanger 803 can allow accumulated heat to be discharged from air inlet 806 into airflow 807. Air inlet 806 may include a lower lip 809 relative to a forward-flying configuration. Lower lip 809 may be further away from motor assembly 802 than upper lip 810, which is opposite to lower lip 809.

[0111] The oil flow path 804 may include a first segment 811 and a second segment 812. In some embodiments, the oil flow path 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 flow path 804 may bypass the upper lip 810.

[0112] Some embodiments may include a thermally conductive material 808 located 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. Alternatively, in some embodiments, the housing 805 may comprise a first material, and the thermally conductive material 808 may comprise a second material different from the first material. The second material may have a higher thermal conductivity than the first material. A second material with higher thermal conductivity may allow heat to be transferred from one location to another faster or more efficiently than the first material, while the first material of the housing may require other characteristics such as cost, manufacturability, weight, or durability.

[0113] In some embodiments, such as the propeller system 800B shown in FIG. 8B, the thermally conductive material 808 may extend along 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 thermally conductive material may surround the air inlet 806. Alternatively, as in the propeller system 800C shown in FIG. 8C, the thermally conductive material 808 may extend from inside the motor assembly 802 to the outside of the motor assembly 802 to better conduct heat generated inside the motor assembly. The thermally conductive material 808 extending from inside the motor assembly 802 to the outside of the motor assembly 802 may include, for example, a plate extending from inside the motor assembly 802 to the outside of the motor assembly 802. The plate may be arranged 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 wrap around the motor assembly 802.

[0114] Figures 9A-9H illustrate example propeller systems 900A-900H consistent with the disclosed embodiments, which are configured to manage icing on the surface of an electric aircraft. Propeller systems 900A-900H may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 in Figures 1A and 1B). The propeller system 900A-900H may include: a propeller 901; a motor assembly 902, which includes, for example, a motor 935, a gearbox 936, and an inverter 937; a heat exchanger 903; an oil flow path 904, which includes first, second, and third sections 911-913); a pump 940; a hull 905, wherein the hull 905 may include an air inlet 906, which includes an upper lip 910 and a lower lip 909 and is configured to direct airflow 907 to the heat exchanger 903; and one or more valves 914.

[0115] When the propeller 901 is oriented in a forward-facing configuration, the lower lip 909 can be positioned relative to and below the upper lip 910 in the direction of gravity. The lower lip 909 can be positioned further away from the motor assembly 902 than the upper lip 910 in the radial direction R of the propeller 901.

[0116] As indicated by the dashed lines and arrows, the oil flow path 904 can circulate through various parts of the motor assembly 902 and the cabin 905. For example, 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 extend along the lower surface of the cabin 905 relative to a forward-flying configuration. The third segment 913 may further branch off from the second segment 912 along the oil flow direction 904 and return to the second segment 912 along the oil flow direction 904. For example, in FIG. 9A, the oil flow direction 904 is the direction indicated by the arrow. In another embodiment, the first segment 911 may be fed into the second segment 912 along the oil flow direction 904 and return from the second segment 912 along the oil flow direction 904.

[0117] In some embodiments, the third segment 913 may branch off from the relatively hot side of the oil flow path and return to the relatively cold 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 near the outlet side of the heat exchanger 903.

[0118] The propeller system 900A may further include a first flow control valve 914. The first flow control valve 914 may be configured to adjust the oil flow rate through the third section 913. In some embodiments, the first flow control valve 914 may be configured to selectively shut off oil flow into or from the third section 913. In another embodiment, the propeller system 900A may include a second flow control valve 915. The first flow control valve may be located at the inlet side of the third section 913, and the second flow control valve 915 may be located at the outlet side of the third section 913. In some embodiments, the flow control valve may be configured to selectively increase or decrease the flow rate through the third section 913. For example, the flow may be opened or closed based on the icing conditions determined above or based on a dedicated air inlet ice sensor, or the flow rate may be adjusted upwards or downwards. In some embodiments, the first flow control valve 914 or the second flow control valve 915 may include a check valve or other unidirectional flow device configured to maintain oil flow in the desired direction. Generally, any section or connection between sections may include such flow control valves.

[0119] In addition to ice management, additional oil flow path segments, such as the third segment 913, advantageously provide more cooling surface area to dissipate heat from the oil. This can reduce the need for a heat exchanger, thereby allowing for a smaller heat exchanger size or improved overall cooling efficiency. However, as mentioned above, it can also introduce greater complexity, ductwork, oil volume, and pump mass. Therefore, as discussed above, in some embodiments, it may be advantageous to limit additional oil flow path segments to align with the surfaces most prone to ice buildup and similarly provide optimal additional cooling surface areas. For example, in some embodiments, it may be advantageous to align with the lower lip of the air inlet where ice buildup is more common.

[0120] In Figure 9A and other figures, the third segment 913 can be represented as branching off, for example, between pump 940 and heat exchanger 903. However, embodiments of this disclosure are not limited thereto. For example, as discussed above with respect to Figure 8A, pump 940 may be absent, or pump 940 may not be coupled to gearbox 936, or it may be located elsewhere. Furthermore, in some embodiments, the third segment may extend from, for example, the outlet side of heat exchanger 903. For example, in some embodiments, the third segment may extend in series from the outlet side of heat exchanger 903 to, for example, another part of inverter 937 or oil flow path 904.

[0121] Figure 9B illustrates an example propeller system 900B consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. The propeller system 900B may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). For example, the propeller system 900B may include the components discussed above with respect to Figure 9A, as well as other components discussed below.

[0122] 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 at a 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 on the output side of the pump 940. The third segment 913 may be fed into the second segment 912 in the direction of the oil flow 904. For example, as shown in FIG. 9B, the third segment 913 may be fed into 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 at a third segment outlet point 917 in the direction of the oil flow 904, the third segment outlet point 917 being downstream of the first segment outlet point 916 in the direction of the oil flow 904.

[0123] Figure 9C illustrates an example propeller system 900C consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. The propeller system 900C may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 900C may include the components discussed above with respect to Figures 9A-9B, as well as additional 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. The third segment 913 may branch off from the first segment 911 at a first segment outlet point 916 in the direction of oil flow 904. The third segment 913 may return to the first segment 911 at a third segment outlet point 917 in the direction of oil flow 904. The third segment outlet point 917 may be located downstream of the first segment outlet point 916 in the direction of oil flow 904. In some embodiments, the third segment outlet point 917 is located upstream of the second segment 912 in the direction of oil flow 904.

[0125] Figure 9D illustrates an example propeller system 900D consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. The propeller system 900D may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 900D may include the components discussed above with respect to Figures 9A-9C, as well as additional components discussed below.

[0126] 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 be connected in series with the first segment 911. In other words, in some embodiments, a first portion of the first segment 911 may be fed into the third segment 913, and the third segment 913 may be fed into a second portion of the first segment 911. An alternative series connection is shown at Figure 9H, in which the third segment 913 extends along the lower surface of the air inlet 906 and the cabin 905 into the heat exchanger inlet 920, through the heat exchanger, and to the heat exchanger outlet 921.

[0127] Figure 9E illustrates an example propeller system 900E consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. The propeller system 900E may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 900E may include the components discussed above with respect to Figures 9A-9D, as well as additional components discussed below.

[0128] 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 at a third segment outlet point 917 in the direction of oil flow 904, which may coincide with and be alternatively referred to as the first segment inlet point. The first segment inlet point 917 may be located downstream of the first segment outlet point 916 in the direction of 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 first segment inlet point 917 may be located upstream of the second segment 912 in the direction of oil flow 904. Additionally, in some embodiments, a first portion of the first segment 911 may be fed into a third segment 913, and the third segment 913 may be fed into a second portion of the first segment 911.

[0129] Figure 9F illustrates an example propeller system 900F consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. The propeller system 900F may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 900F may include the components discussed above with respect to Figures 9A-9E, as well as additional components discussed below.

[0130] 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 pass around substantially all air inlets 906. For example, the third segment 913 may be divided into several sub-segments at a first point of the air inlet 906 (such as the upper lip 910), and the sub-segments may merge at a second point of the air inlet 906 (such as the lower lip 909).

[0131] Figure 9G illustrates an example propeller system 900G consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. The propeller system 900G may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 900G may include the components discussed above with respect to Figures 9A-9F, as well as additional components discussed below.

[0132] 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 pass around substantially all air inlets 906 in a single loop.

[0133] Figure 9H illustrates an example propeller system 900H consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. Propeller system 900H may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). Propeller system 900E may include the components discussed above with respect to Figures 9A-9G, as well as additional components discussed below.

[0134] 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, as shown in FIG9H, the third segment 913 may extend continuously from the first segment 911 to the second segment 912 along the air inlet 906.

[0135] Figures 10A and 10B respectively illustrate example propeller systems 1000A and 1000B consistent with the disclosed embodiments, which are configured to manage icing on the surface of an electric aircraft. Propeller systems 1000A and 1000B may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 in Figures 1A and 1B). Propeller systems 1000A and 1000B for managing icing on the surface of electric aircraft may include: a propeller 1001; a motor assembly 1002 including, for example, a motor 1035, a gearbox 1036, and an inverter 1037; a heat exchanger 1003; an oil flow path 1004 including a first section 1011 and a second section 1012; a pump 1040; a hull 1005, wherein the hull 1005 may include an air inlet 1006 including an upper lip 1010 and a lower lip 1009 and configured to direct airflow 1007 to the heat exchanger 1003; and a heat pipe loop 1013.

[0136] The components of propeller systems 1000A and 1000B can be similar to those of propeller systems 900A-900H discussed above, wherein the reference numerals begin with "10" instead of "9". For example, the oil flow path 1004 in Figures 10A-10B can be similar to the oil flow path 904 in Figures 9A-9H. Therefore, descriptions of some components can be omitted here. However, a significant difference in Figures 10A-10B is that the heating function previously performed by the third segment 913 of the oil flow path 904 can be performed by the heat pipe loop 1013.

[0137] For example, the oil flow path 1004 can be configured to thermally couple the heat exchanger 1003 to the motor assembly 1002. The oil flow path 1004 may include a first segment 1011 and a second segment 1012. The heat pipe loop 1013 may include a heat pipe as a third segment independent of the oil flow path. For example, the heat pipe loop 1013 may be configured to circulate a phase change material. Using a heat pipe allows for heating of the air inlet without circulating oil to the inlet. This can reduce the total amount of oil contained in the aircraft and reduce the risk of oil leaks.

[0138] The heat pipe loop 1013 can be configured to collect heat from a heat source and discharge heat to the lower lip 1009. A first segment 1011 of the oil flow path 1004 can pass through the motor assembly 1002, and a second segment 1012 can pass through the heat exchanger 1003. In some embodiments, as shown in FIG10A, the heat source may include the heat exchanger 1003. For example, the heat pipe loop 1013 may be thermally coupled to the heat exchanger 1003, such as by being placed in close thermal contact with it or by integrating the heat pipe loop into the heat exchanger 1003. In some embodiments, as shown in FIG10B, the heat source may include the motor assembly 1002. In some embodiments, the heat source may include a thermally conductive material 1008 located between the motor assembly 1002 and the housing 1005.

[0139] Figure 11 illustrates an example propeller system 1100 consistent with the disclosed embodiments, configured to manage icing on the surface of an electric aircraft. The propeller system 1100 may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 1100 may include: a propeller 1101; a motor assembly 1102 including, for example, a motor 1135, a gearbox 1136, and an inverter 1137; a heat exchanger 1103; an oil flow path 1104 including a first section 1111 and a second section 1112; a pump 1140; and a hull 1105 including an upper lip 1110 and a lower lip 1109, and configured to direct airflow 1107 to the heat exchanger 1103.

[0140] The components of propeller system 1100 may be similar to those of propeller systems 900A-900H, 1000A, or 1000B discussed above, wherein the reference numerals begin with "11" instead of "10" or "9". For example, the oil flow path 1104 of FIG11 may be similar to the oil flow path 1004 of FIG10A-FIG. or the oil flow path 904 of FIG9A-FIG. Therefore, descriptions of some components may be omitted here. In the embodiment of FIG11, heat exchanger 1103 may be located at the opening of inlet 1106 (such as upper lip 1110 or lower lip 1109), thereby directly heating the upper or lower lip through thermal contact with heat exchanger 1103.

[0141] For example, oil flow path 1104 can be configured to thermally couple heat exchanger 1103 to motor assembly 1102. Oil flow path 1104 can pass through motor assembly 1102 and heat exchanger 1103. Cabin 1105 may include air inlet 1106, at which heat exchanger 1103 is arranged.

[0142] In Figure 11, a heat exchanger 1103 can be arranged at an air inlet 1106, which is configured to passively prevent icing without requiring an additional oil flow section. By arranging the heat exchanger 1103 directly at or near the inlet, icing can be prevented through heat conduction between the heat exchanger 1103 and the air inlet 1106.

[0143] In some embodiments discussed above, high propeller acceleration can be used to remove icing. In some embodiments, propeller acceleration can be further used to determine the presence of icing. Figure 12 illustrates an example system 1200 for determining icing conditions on the propeller or other surfaces of an aircraft, consistent with the disclosed embodiments. For example, system 1200 can be used to determine icing condition inputs, as discussed above with reference to, for example, Figures 2, 3, 5, or 6. System 1200 may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). System 1200 may include: a propeller 1201, a gearbox 1202, a motor 1203, an inverter 1204, and one or more accelerometers. For example, the accelerometers may be located in a module of the motor assembly, such as within gearbox 1202, motor 1203, or inverter 1204. Alternatively or additionally, the accelerometers may also be located at a component of propeller 1201 or at a connection between modules. As schematically shown, accelerometers can be located externally or internally to the module. Multiple accelerometers can be provided on a given module, thereby enabling the monitoring of vibrations or other dynamics, for example, in multiple degrees of freedom.

[0144] Accelerometer 1210 can be configured to, for example, monitor vibrations or other dynamics of a propulsion system. In some embodiments, multiple accelerometers 1210 can be provided on a given module to monitor these dynamics, for example, in multiple degrees of freedom, such as orthogonal x, y, or z axes or other degrees of freedom. In some embodiments, additional accelerometers can be provided to achieve 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 spectrum 1211 can deviate from expected values ​​for a given set of flight conditions. For example, the vibration amplitude 1212 at a certain frequency value may include a normal or expected component 1213 (shown with shaded bars) and additional anomalous components 1214 (shown with white or blank bars), which can indicate icing conditions. Since icing alters the mass distribution of rotating components such as propeller blades, hubs, or shafts, deviations from expected values ​​can indicate icing conditions. In other words, deviations from expected vibration amplitudes at predetermined frequencies of a known set of flight conditions can indicate changes in mass distribution caused by icing. In some embodiments, such deviations can be inferred to be caused by icing conditions, for example, based on modeling that identifies ice-related deviations or based on weather data, flight conditions, or other factors indicating that vibration deviations may be caused by icing conditions. In some embodiments, ice buildup can attenuate certain frequencies or shift natural vibration patterns to frequencies higher or lower than expected. Therefore, in some embodiments, determining icing conditions may include determining that frequencies are lower than expected or that natural patterns have deviated from expected values.

[0145] In some embodiments, the set of flight conditions monitored may correspond to normal flight conditions. In some embodiments, flight conditions may be induced to detect icing conditions. For example, propeller speed, torque, or other parameters may be adjusted to generate icing conditions that are easier to detect by producing more noticeable or identifiable vibrations or other disturbances.

[0146] 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, electric aircraft engines may use flight control systems to monitor propeller parameters, which relies on secondary estimation rather than direct measurement. Because the estimator within the flight control system cannot accurately measure acceleration, velocity, torque, or other parameters, using this system may prevent the electric engine from operating at its maximum power capacity. For example, an electric engine design may be limited to a slew rate, for example, of 3000 Nm / s or less, at positive velocities of 50 RPM or higher. While this is acceptable for normal flight, it is beneficial for other reasons, such as measuring icing or monitoring system dynamics, to enable the engine to perform accelerations outside its typical operating range. Therefore, in some embodiments, motor position sensors can be used to perform the measurements discussed above. An example motor position sensor is discussed below with respect to Figure 13.

[0147] Figure 13 illustrates an example system 1300 for determining icing conditions on an aircraft propeller or other surface, consistent with the disclosed embodiments. System 1300 may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). For example, system 1300 may include: a propeller 1301, a gearbox 1302, a motor 1303, an inverter 1304, and a motor position sensor 1305. Motor position sensor 1305 may be configured to directly measure angular position. For example, motor position sensor 1305 may be configured, for example, at the output of propeller 1301, gearbox 1302, or motor 1303. In some embodiments, motor position sensor 1305 may include, for example, a resolver. Motor position sensor 1305 may be configured to directly measure angular position with high accuracy and high speed for greater feedback control of, for example, propeller speed and torque. Therefore, adding a motor position sensor can support higher torque oscillation at increased propeller speeds, which can be used to achieve higher amplitude adjustment parameters discussed above in the embodiments of this disclosure.

[0148] Figure 14 illustrates an example system for determining icing conditions on an aircraft propeller or other surface, consistent with the disclosed embodiments. System 1400 may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of 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 include a motor control unit (MCU) 1401 and a motor position sensor 1405, the MCU 1401 having a motor control module 1402 and a position estimation module 1403. Motor position sensor 1405 may correspond to, for example, motor position sensor 1305 of Figure 13. In some embodiments, motor position sensor 1405 may include, for example, a resolver. Position estimation module 1403 may receive voltage phase information 1406 and current phase information 1407 from an electric engine (such as inverter 1304 from Figure 13). In some embodiments, voltage phase information 1406 and current phase information 1407 can be generated by sensors on the phase connection of inverter 1304 of FIG. 13. Position estimation module 1403 can estimate the angular position of the propeller (propeller 1301 as shown in FIG. 13). Motor control module 1402 can receive a position estimation signal from position estimation module 1403 and a position measurement signal from motor position sensor 1405. Motor control module 1402 can output pulse width modulation (PWM) command 1408 based on the position estimation signal and the position measurement signal to perform high-speed, accurate angular measurement of the propeller in VTOL or other distributed propulsion aircraft.

[0149] In some embodiments, the oil path can flow through other icing-prone areas to serve the dual purpose of preventing icing and providing secondary heat exchange surfaces. For example, a hubcap or propeller blade can be configured to circulate hot oil to act as a primary or secondary heat exchanger while managing deposits on these surfaces. In some embodiments, using such a surface as a primary heat exchanger can completely eliminate the need for a dedicated heat exchanger. For example, in some embodiments, the heat exchanger 1511 discussed below with respect to FIG. 15 can be eliminated when, for example, hubcap 1501 provides sufficient heat exchange surface.

[0150] Figure 15 illustrates an example propeller system 1500 consistent with the disclosed embodiments, configured to manage ice buildup on a hub cover 1501. The propeller system 1500 may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 1500 may include: a hub cover 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 hot oil path 1512, a cold oil path 1513, a shaft oil path 1514, and a hub cover oil path 1515. In this context, "hub cover" may refer to a cover or other aerodynamic outer surface at the center of rotation of the propeller. The hub cover 1501 can be mounted to the propeller shaft 1507 via the propeller flange 1502. The oil path 1514 in the propeller shaft 1507 can be connected to the propeller flange 1502. The oil path 1514 in the propeller shaft 1507 can travel along the propeller shaft 1507 toward the propeller flange 1502 and the hub cover 1501.

[0151] The oil flow path can be described as beginning at an oil collector 1516, which collects oil that has been heated by the various components of the propeller system 1500 (e.g., windings 1504, magnets 1505, gearbox 1506, or inverter (not shown, but fed via inverter feeder 1509)). The heated oil can be pumped by pump 1510 through hot oil path 1512 into heat exchanger 1511. Heat exchanger 1511 can cool the oil by exchanging heat with, for example, an airflow passing through heat exchanger 1511, and deliver the oil back to the various components via cold oil path 1513 for reheating. The oil can travel along shaft oil path 1514 to be delivered to hub cap 1501 via, for example, propeller flange 1502. At the hub cap, for example, the oil can circulate via hub cap oil path 1515. The hubcap oil path 1515 may include, for example, conduits, microtubes, or other pathways configured to distribute oil along the inner surface. For example, the hubcap path may include a channel similar to those used in a heat exchanger and may be coupled or brazed to the hubcap 1501 or integrally formed within the housing of the hubcap 1501. Hot oil may be circulated through the hubcap oil path 1515 by, for example, the centrifugal force of a pump 1510 or a spinning propeller. For example, in some embodiments, the hubcap oil path 1515 may be introduced at a radially inward portion of the hubcap 1501 and returned to a more radially outward portion of the propeller flange 1502 to provide net centrifugal force to the oil in the hubcap oil path and aid its circulation. Thus, hot oil can enter through the central portion of the propeller flange 1502 and circulate through the oil flow path 1515 to exchange heat with cold surfaces and to melt or prevent ice buildup. The oil can then return to the propeller flange 1502 and be guided back to the stationary part of the propeller system 1500, such as by traveling through the propeller bearing 1503 to the winding 1504 or other hot parts, and finally return to the oil collector 1516 to repeat the oil flow cycle.

[0152] Because the de-icing path of the hub cap 1501 cools the oil reaching the oil collector 1516 to a lower temperature than it would otherwise be without this path, the hub cap oil path reduces the cooling requirements of the heat exchanger 1511, allowing for a smaller design or even eliminating the need for a heat exchanger altogether. Reducing or eliminating the heat exchanger also reduces or eliminates the need for a corresponding air inlet, allowing for a significantly more streamlined propeller nacelle profile, thereby reducing drag and improving energy efficiency.

[0153] Figure 16 illustrates an example system 1600 for managing ice buildup on a propeller hub cover, consistent with the disclosed embodiments. System 1600 may include subsystems of, for example, the propeller system 1500 of Figure 15. For example, system 1600 may include a portion of, for example, an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). System 1600 may include: a pump 1610, a stationary oil chamber 1611, a tail bearing 1612, a rotating oil chamber 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 can force oil into the stationary oil chamber 1611, through the stationary channel 1617 (which may optionally pass through the tail bearing 1612), and into the rotating oil chamber 1613. The rotating oil chamber 1613 can be configured to spin relative to the stationary component via a sealed bearing system 1618, causing it to move together with other rotating components of the propeller system, such as the propeller shaft 1607 or the propeller flange 1602. Oil can enter the shaft oil path 1614 through the rotating oil chamber 1613 and enter the hub cover (not shown) through the shaft flange 1602. The rotating oil chamber 1613 and the stationary oil chamber 1611 can thus supply hot oil from the stationary component of the propeller-electric engine to the spinning component (the hub cover 1501 as shown in Figure 15).

[0154] Figures 17A-17B illustrate an example of a propeller system 1700 consistent with the disclosed embodiments, which is configured to manage icing on the hub cap or propeller blades. The propeller system 1700 may include, for example, a portion of an electric aircraft (such as the VTOL aircraft 100 of Figures 1A and 1B). The propeller system 1700 may include: a hub cap 1701, a hub cap oil path 1715, a blade passage 1716, a heat conductor 1717, an oil path inlet 1718, an oil path outlet 1719, and blades 1720.

[0155] The propeller system 1700 may be similar to system 1500 of Figure 15, but with an ice management system added within the blade 1720. For example, oil may be distributed from the hub cap oil path (also referred to as the hub cap channel) 1715 to the internal blade channel 1716, which may be formed, for example, within the blade material or incorporated into the hollow interior. In some embodiments, as seen at the top of Figure 17A, the blade channel 1716 may extend substantially along the entire length of the blade 1720. For example, in some embodiments, the force exerted on the oil due to the rotation of the propeller blade 1720 may be substantially equal on the radial outflow section 1716a and the radial inflow section 1716b, such that the reaction forces can largely cancel each other out, leaving only the force exerted along the oil flow path from, for example, a pump or other circulation mechanism, and pressure loss along the oil path. Therefore, in some embodiments, it may be desirable to extend the internal blade channel 1716 along substantially the entire length of the blade 1720 to prevent ice formation and create additional heat exchange surface. For example, if all rotating hub caps and blades function as heat exchangers, then in some embodiments, the size of the heat exchanger at the hull can be greatly reduced, or the heat exchanger can be eliminated entirely, thereby saving costs and reducing weight and drag.

[0156] However, another concern is the potential presence of air in the oil circulating through the hub cap oil path 1715 and the blade passage 1716. The more radially outward the blade passage extends, the more the blade 1720 acts as a centrifuge to separate air from the oil. This can disrupt fluid flow and potentially create undesirable imbalances within the propeller blade. Therefore, in some embodiments, as seen at the bottom of Figure 17A, the blade passage 1716 may extend only a portion of the blade, such as extending a distance of, for example, 20%, 30%, 40%, 50%, 60%, or 70% of the blade radius measured from the axis of rotation. The specific radius chosen can depend on fluid flow characteristics, passage width, expected blade operating conditions, and the degree to which the oil may degas. In some embodiments, the remainder of the blade 1720 can be heated, for example, by providing a heat conductor 1717 from the radially outward portion of the blade passage 1716 to the blade 1720.

[0157] Furthermore, it should be noted that the radially inward heating characteristics of the blade passage 1720 located at the bottom of Figure 17A can be combined with the ice management cycles described above. For example, while blade passage 1716 may be more suitable for heating the radially inward portion of blade 1720, some ice management cycles may be more effective for the radially outward portion. By providing blade passage 1716 and performing ice management cycles (e.g., adjusting propeller speed), ice can be effectively managed along the entire length of blade 1720. Similarly, providing blade passage 1716 can reduce the required amplitude of management cycles, because, for example, propeller RPM or tip Mach number will not need to be high enough to dislodge ice in the radially inward portion, but instead can be designed to manage ice only in the outer portion of blade 1720. Therefore, combining blade passages with ice management cycles can provide superior ice management.

[0158] As discussed above and further illustrated in Figure 17B, in some embodiments, oil may circulate only through the blades 1720 and may not circulate through the dedicated heat exchange channels in the hubcap 1701. Instead, the oil flow may enter through one or more oil path inlets 1718 and be distributed to each blade channel 1716. After circulating through the blade channels, the circulated oil may be recombined at one or more oil path outlets 1719. It may be necessary to concentrate the oil flow into the propeller blades 1720 to improve the performance of the oil flow system as a heat exchanger rather than just as an ice management system. For example, while the surface of the hubcap 1701 can provide a constant airflow in a cruise configuration, this may not be the case during hovering or slow ascent or descent. In this case, only the rotating blades can continue to provide continuous contact with the airflow strong enough to perform heat exchange with the oil within the blades. Therefore, in some embodiments, by concentrating the oil flow in the propeller blades 1720, a dedicated air-oil heat exchanger (such as heat exchanger 803 in FIG. 8A) can be reduced or eliminated, which also reduces or eliminates the need for drag-causing features (such as air inlet 806 in FIG. 8A). For example, when the propeller blades 1720 function as the sole heat exchanger for the propeller assembly, since the sole heat exchanger is located outside the aircraft skin 1722 (such as outside the cabin, boom, or other external aerodynamic surfaces), an air inlet can be eliminated, thereby eliminating the need to draw air into the aircraft interior. In some embodiments, multiple propeller blades 1720 can function as the main heat exchanger in the propeller system. The blades can be considered the “primary” heat exchanger when a large portion of the heat generated, for example, by the motor assembly, is transferred to the external environment through heat conduction via the propeller blades. For example, a large 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, the blades are considered the “primary” heat exchanger when, for example, no other heat transfer components (e.g., cooling fins or an air-oil heat exchanger) transfer more heat from the motor assembly to the external environment than the propeller blades transfer. Alternatively or additionally, the blades may be considered the “primary” heat exchanger when the propeller assembly does not have other components designed to function as a heat exchanger.

[0159] Figures 18A-18K illustrate example systems for managing ice buildup on propeller assemblies consistent with the disclosed embodiments. As discussed below, the ice management system according to embodiments of this disclosure can utilize the electrical or mechanical power of the propeller to wirelessly generate heat in moving parts of the propeller assembly, such as propeller blades or hub caps.

[0160] For example, in some embodiments, an array of magnets may be arranged on the stationary portion of the propeller assembly. In this case, "stationary" can refer to components on the aircraft that do not rotate with the propeller blades, such as motor assemblies, booms, hulls, etc. In some embodiments, the magnets may include permanent magnets. In some embodiments, the magnets may include electromagnets coupled to AC or DC power circuitry.

[0161] Magnets can be arranged close to conductive portions of movable parts of the propeller assembly. In some embodiments, the conductive portion may include conductive strips configured to generate eddy currents as material moves through the magnetic field generated by the array of magnets. These eddy currents can be conducted to other parts of the propeller assembly via further electrically conductive material, such as wiring embedded in the blades, hub cap, or other icing-prone surfaces. In some embodiments, the conductive portion may include windings. Magnets can be configured to induce current in the windings. The current can then flow to other parts of the blades and hub cap, for example, via embedded wiring, which can generate heat at desired locations through resistance heating to manage icing.

[0162] The following discusses various embodiments of electric ice management. It should be understood that, as with the embodiments in Figures 1-17B above, the features described in each of Figures 18A-18K can be used in combination with each other, and further, features from one illustrated embodiment can be incorporated into or replaced by an embodiment in another illustrated embodiment. For example only, the coil shown in Figure 18J can supplement or replace the permanent magnet shown in Figure 18G.

[0163] Furthermore, although Figures 18A-18K are described with respect to a tilting propeller, the embodiments of this disclosure are not limited thereto. For example, the features described below can be implemented on, for example, a lift propeller or another type of aircraft propeller assembly.

[0164] As 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 via a propeller flange 1816; a hub cover 1801; and propeller blades 1820.

[0165] The propeller assembly 1800 may include a hub cover rod 1832 located within a hub cover 1801. The hub cover rod 1832 may extend, for example, from the propeller hub 1818 and be coaxial with the axis of rotation of the propeller shaft 1814. The hub cover rod may be fixed relative to the propeller hub 1818 and may be configured to rotate together with the propeller hub 1818 and other rotating elements of the propeller assembly 1800. In some embodiments, the hub cover rod may include another rotating element of the propeller assembly, such as the propeller flange 1816, the hub cover 1801, or other mechanisms within the hub cover 1801 (e.g., a pitch control lever or yoke (not shown)), or may be fixed to said other rotating element. As shown, the hub cover rod 1832 cantilevered over the propeller hub 1818, but embodiments of this disclosure are not limited thereto. For example, in some embodiments, the hubcap rod 1832 may be cantilevered over the hubcap 1801, or it may connect the propeller hub 1818 to the hubcap 1801. In some embodiments, a cantilevered hubcap rod may be preferred due to its compact and lightweight design, while the hubcap rod 1832 connecting the propeller hub 1818 to the hubcap 1801 may provide, for example, greater stability and durability of the propeller structure.

[0166] Magnet 1830 can be suspended from hubcap rod 1832 via bearing 1833 and arm 1836. For example, magnet 1830 may include one or more permanent magnets. Bearing 1833 can decouple magnet 1830 from the rotational motion of the propeller assembly, such that in the horizontal thrust orientation shown, magnet 1830 is held downward by gravity while hubcap rod 1832 rotates with the propeller. In a fully vertical thrust orientation, magnet 1830 can also be held sufficiently decoupled from the rotation of the propeller assembly by inertia, making ice management effective in both lift and cruise configurations. However, it should be noted that the tilting propeller is often oriented at a small angle relative to the vertical, even during takeoff, landing, and hovering, so that gravity can still help keep magnet 1830 stationary.

[0167] The hubcap 1801 may include a conductive portion 1831 positioned proximal to the magnet 1830. In some embodiments, as shown in FIG18A, the conductive portion 1831 may include a metal sheet 1831a, such as aluminum, copper, iron, or steel (e.g., carbon steel, electrical steel, stainless steel, etc.). The conductive portion 1831 may, for example, be attached to the inner surface of the hubcap 1801, or it may be embedded within the hubcap 1801. The conductive portion may be located on the side of the hubcap, as seen in FIG18A. For example, the side of the hubcap may refer to the portion of the hubcap 1801 that is radially outward toward the propeller blade 1820 beyond the forward flight direction. In some embodiments, the metal sheet may continuously wrap around the inner surface of the hubcap, as shown in the upper left corner of FIG18A (the conductive portion 1831a is shown as a continuous strip spanning a complete circular path from 0 to 2π in an "unrolled" form). In some embodiments, a plurality of magnetic field sensors 1835 may be arranged along the conductive portion 1831, as discussed below.

[0168] When the propeller is in operation, the relative motion between the suspended magnet 1830 and the hub cap 1801 can generate eddy currents in the conductive portion 1831, thereby generating heat in the conductive portion 1831. This heat can then heat the hub cap to manage icing. In some embodiments, the generated heat can be distributed via a wiring path 1817. The wiring path 1817 may include, for example, a thermally conductive material system such as carbon fiber, wire, or metal mesh, and can be configured to distribute the eddy current heat to icing-prone surfaces of the propeller assembly, such as the hub cap 1801, the blades 1820, or other locations via thermal conduction.

[0169] The embodiment of the icing management system shown in Figure 18A provides a simple, passive, fail-safe design that can operate without dedicated control components. This "always-on" design also reduces the burden of ice detection. For example, while understanding the icing status on an aircraft surface may be important, it may not be necessary to specifically determine when icing management should be activated.

[0170] In some embodiments, an array of magnetic field sensors 1835 may be provided near the conductive portion 1831. The magnetic field sensors 1835 may be configured to detect the magnetic flux passing over the magnet 1830 during propeller rotation. This sensor data may be transmitted to an inverter or control circuitry, such as that of the motor assembly 1802, which serves as a rotational position sensor. For example, the sensor data may be transmitted to a stationary portion of the propeller assembly via, for example, wireless transmission, slip rings, etc. Therefore, the rotational position sensor can be integrated into the structure of the icing management system to reduce the number of separate dedicated sensors and control circuitry in the propeller assembly 1800.

[0171] As an alternative to or in addition to eddy current heating, ice management can be achieved in some embodiments by generating current and drive current in the hub cap 1801 or blade 1820. For example, as schematically shown in the upper left corner of FIG18B, the conductive portion 1831 may include a plurality of windings 1831b. When the propeller is in operation, the relative movement between the suspended magnet 1830 and the hub cap 1801 can sense current in the windings 1831b of the conductive portion 1831, and then distribute the current through wiring path 1817. Wiring path 1817 may include, for example, conductive portions (such as wires) that distribute current to, for example, the hub cap 1801 or blade 1820, and manage ice on its surface by resistance heating. In some embodiments, resistance heating can be adjusted at desired locations by customizing the thickness or other structural characteristics of the wiring path 1817. For example, if more heat is desired to be generated at the tip of blade 1820 than at its root, the segment of wiring path 1817 can be thinner at the blade tip to increase resistance heating at those locations.

[0172] In some embodiments, switch 1834 may be configured to selectively enable or disable electrical contact between wiring path 1817 and conductive portion 1831. For example, in some embodiments, switch 1834 may include a temperature-controlled switch configured to disable electrical contact when the temperature at switch 1834 exceeds a predetermined threshold. Alternatively or additionally, switch 1834 may include an active control switch that may be operated by, for example, a pilot or flight control system. For example, in some embodiments, switch 1834 may be configured to communicate wirelessly or via a slip ring with control circuitry on a stationary portion of the aircraft. In some embodiments, switch 1834 may be battery-powered or powered or charged by current induced in the winding 1831b of conductive portion 1831. By providing switch 1834, wiring path 1817 can be disconnected when ice management is not required, reducing energy loss while maintaining minimal complexity in the ice management control architecture.

[0173] In some embodiments, switch 1834 may be designed with a default "on" setting, meaning the switch may be configured to connect wiring path 1817 to conductive portion 1831 by default and 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 ice management capabilities. Such a failure can be detected by determining that heating is activated when it should not be heating, which can be determined by efficiency losses in the propeller assembly due to heat generation.

[0174] In some embodiments, multiple switches may be provided to selectively enable or disable heating of different zones of the propeller assembly. For example, different zones may include, for instance, hub cover 1801, or an area of ​​hub cover 1801, a single blade 1820, or an area of ​​a single blade 1820, or all blades 1820. By aligning different zones, heating power can be selectively concentrated where needed, depending on icing conditions.

[0175] Figures 18C and 18D schematically illustrate additional configurations for ice management consistent with embodiments of the present disclosure. For example, the embodiments according to Figures 18C and 18D may be similar to the embodiments described with respect to Figures 18A and 18B, except as described below.

[0176] As shown in Figure 18C, the magnet 1830 can face the front portion of the hub cap 1801, and the conductive portion 1831 (the metal sheet 1831a shown in Figure 18A or the multiple windings 1831b shown in Figure 18B) can be located at the front portion. In this case, the “front” of the hub cap can refer to the propulsion direction of the hub cap. For example, in the case of a tilting propeller, when the propeller is in a horizontal thrust configuration or a cruise configuration, the front can correspond to the forward flight direction. The advantage of the forward-facing arrangement is that it places the conductive portion near the more icy areas of the hub cap 1801. Additionally, in some embodiments, the forward-facing arrangement can better accommodate space requirements by positioning the magnet 1830, the hub cap rod 1832, and the bearing 1833 away from other components (e.g., the pitch control mechanism (not shown)).

[0177] Alternatively or additionally, as shown in FIG18D, the magnet 1830 may be positioned away from the front of the hub cap 1801, such as facing the propeller hub 1818 or propeller flange 1816. Furthermore, the conductive portion 1831 may be mounted to or embedded in the propeller hub 1818 or propeller flange 1816. For example, a front view of an example propeller hub 1818 is shown in the lower left of FIG18D, wherein the conductive portion 1831 includes a flat, disc- or washer-shaped conductive sheet 1831a, which is configured as described above to generate eddy current heating. Alternatively or additionally, as shown in the upper left corner of FIG18D, the conductive portion 1831 may include a plurality of windings 1831b arranged in a circle in the plane of the propeller hub 1818 and configured to generate and drive current through wiring path 1817.

[0178] In some embodiments, the magnet 1830 and the conductive portion 1831 may be integrated into, for example, the bearing 1833 and the hub cap rod 1832, respectively. For example, as shown in FIG18E, the bearing 1833 (schematically shown as a sleeve surrounding three rollers in the upper left corner of FIG18E) may include a plurality of magnets 1830 arranged around the inner surface of the bearing facing a plurality of windings 1831b as conductive portions 1831. The plurality of windings may be arranged on or within the hub cap rod 1832. A counterweight 1837 may be suspended on the arm 1836 to hold the bearing 1833 and the magnets 1830 in a static orientation relative to the direction of gravity as the hub cap rod 1832 rotates. For example, the bearing 1833 may include a roller 1850 located between the inner bearing surface 1851 (e.g., on the outside of the rod 1832) and the outer bearing surface 1852 (e.g., on the inner sleeve of the bearing 1833). Therefore, current can be induced in the windings, and this current is distributed to the hub cap 1801 or the blade 1820 via wiring path 1817. In some embodiments, the length of arm 1836 can be optimized to increase the gravity-induced torque on bearing 1833 and maintain the gravity-induced torque in the desired orientation. In some embodiments, as seen in the lower left corner of FIG18E, arm 1836 can be eliminated, and counterweight 1837 can be integrated into the housing of bearing 1833 to generate a mass imbalance that keeps bearing 1833 in the desired orientation. The configuration of FIG18E allows for compact and efficient electrical generation without any control architecture or electrical connection to stationary parts of propeller assembly 1800.

[0179] In some embodiments, as shown in FIG18F, the hubcap rod 1832 may be fixed to a stationary portion of the propeller assembly or aircraft such that relative rotation occurs between the hubcap rod 1832 and the hubcap 1801. For example, the hubcap rod 1832 may include a pitch control lever passing through the propeller shaft 1814. The pitch control lever 1832 may remain stationary relative to the direction of rotation about the axis of the propeller shaft 1814 and may be linearly translated along the propeller axis (as indicated by the double arrows) to actuate pitch controls, such as the yoke or linkage 1845 and the blade actuation pin 1846. For example, the pitch control lever 1832 may be linearly translated over a stationary portion of the propeller system or aircraft via, for example, a pitch actuator 1847. When the yoke 1845 and the blade actuation pin 1846 can rotate together with other rotating parts of the propeller system, the pitch control lever 1832 can be rotated apart from the yoke 1845 via the bearing 1833, in which case the bearing 1833 may include, for example, a thrust bearing.

[0180] Magnet 1830 can be attached to pitch control rod 1832 via arm 1836 in a manner similar to that discussed above. However, in the embodiment of FIG. 18F, the arm can be rigidly coupled to pitch control rod 1832. Therefore, in the configuration of FIG. 18F, magnet 1830 and arm 1836 may not require gravity to remain fixed as conductive portion 1831 rotates about magnet 1830 and arm 1836. Thus, a more stable configuration can be ensured, and additional arms 1836 and magnets 1830 can be arranged symmetrically around hub cap rod 1832. For example, the second magnet 1830 at the top in FIG. 18F can be positioned in the opposite direction in diameter to the first magnet 1830 shown at the bottom. In some embodiments, additional magnets 1830 can be arranged around hub cap rod 1832, such as 3, 4, 5, 6, or any suitable number. This not only increases heat or electricity generation but also provides a simpler balance for the propeller system.

[0181] Alternatively or additionally, in some embodiments, one or more magnets 1830 or arms 1836 may be arranged symmetrically around the hubcap rod 1832 via bearings 1833, as discussed above with respect to, for example, Figure 18A. For example, additional magnets 1830 may be arranged symmetrically relative to the suspended magnets of Figure 18A, or multiple magnets of two or more may be arranged symmetrically around the hubcap rod 1832. In some embodiments, one or more magnets 1830 may be balanced by counterweights, similar to the counterweight 1837 discussed above.

[0182] In some embodiments, to reduce the impact of linear axial displacement that will occur between magnet 1830 and conductive portion 1831 during pitch control, at least one of magnet 1830 or conductive portion 1831 may be sized or positioned such that magnet 1830 and conductive portion 1831 remain sufficiently close throughout the entire permissible pitch angle range. In some embodiments, the sizing or layout of magnet 1830 and conductive portion 1831 may be optimized for a primary pitch angle or a range of pitch angles, which is intended for cruise orientation where ice management may be of paramount importance. In some embodiments, arm 1836 and magnet 1830 may be linearly decoupled from pitch control lever 1832 via, for example, a rack and pinion system (not shown) to maintain proximity of magnet 1830 and conductive portion 1831. For example, in this case, magnet 1830 may be axially constrained by grooves or tracks 1848 coupled to rotating portions of the propeller assembly (e.g., hub cap 1801 or propeller hub 1818). The groove or track 1848 allows the magnet 1830 to maintain relative rotational movement with respect to the conductive portion 1831 via, for example, a bearing or other low-friction guide (not shown).

[0183] In some embodiments, magnets 1830 may be mounted to a propeller assembly or a stationary part of an aircraft. For example, as shown in FIG18G, a plurality of magnets 1830 may be mounted to a motor assembly 1802 and surrounding a propeller shaft 1814. For example, magnets 1830 may be mounted directly on the outer surface of the motor assembly 1802, or may be spaced apart from the motor assembly 1802 on an extension (e.g., a cylindrical mount 1838). The cylindrical mount 1838 may space the magnets 1830 further away from the motor assembly 1802 and closer to the winding 1831b of the conductive portion 1831. This can result in improved current generation efficiency due to the reduced gap between the magnet and the winding. Overheating and demagnetization of the magnets 1830 can also be prevented by reducing thermal contact with the motor assembly 1802. Alternatively or additionally, magnets 1830 may also be mounted to another stationary component, such as a boom, hull, motor mount, etc. The conductive portion can be mounted to, for example, a propeller hub 1818 and can include multiple windings surrounding a propeller flange 1816. Alternatively or additionally, the conductive portion can be mounted on another moving part of the propeller, such as the propeller flange 1816 or the propeller shaft 1814. Furthermore, as mentioned above, although the conductive portion 1831 is shown as including multiple windings 1831b, the embodiments of this 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 FIG18D.

[0184] For example, the upper left of Figure 18G shows the motor assembly 1802 viewed from the propeller flange 1816 side along the axis of propeller shaft 1814. Magnet 1830 and magnetic field sensor 1835 can be arranged around the facing surface of motor assembly 1802 or another stationary component as discussed above. The lower left of Figure 18G shows the propeller flange 1816 viewed from the motor assembly 1802 side along the axis of propeller shaft 1814. Winding 1831b and auxiliary magnet 1839 can be arranged around the facing surface of propeller flange 1816 or another rotating component as discussed above. The auxiliary magnet can be configured to provide a reference magnetic field for detection by magnetic field sensor 1835, thereby allowing the magnetic field sensor to be located on the stationary side of propeller system 1800. This enables direct rotational position detection without the need for wireless power or signal transmission.

[0185] In some embodiments, magnet 1830 may be arranged facing conductive portion 1831, which is located on or within other rotating components of propeller assembly 1800, such as blade 1820. For example, as seen in Figures 18H and 18I, conductive portion 1831 may be located, for example, at the trailing edge of blade 1820 and may be arranged toward magnet 1830. In some embodiments, magnet 1830 may be mounted at an angle to a mounting surface to accommodate the profile of blade 1820. For example, as seen in Figure 18H, conductive portion 1831 may include, for example, winding 1831b configured to drive current through wiring path 1817. By embedding the winding directly into propeller blade 1820, heat can be distributed more efficiently across each blade. Simultaneously, ice management of hub cap 1801 can be achieved by routing wiring path 1817 through hub cap or by independently heating hub cap 1801 using another disclosed technique.

[0186] Alternatively or additionally, as seen in FIG18I, the conductive portion may include a metal sheet 1831a extending along the length of the blade 1820 and configured to generate eddy current heating within the blade 1820. The heat can then be distributed via wiring path 1817 to other portions of the blade 1820 or the hub cap 1801. In some embodiments, the conductive portion 1831 may serve multiple functions on the blade 1820. For example, the conductive portion may form part of a blade beam or other structural support frame. As shown in FIG18I, the conductive portion may include part of a lightning grounding path leading from the propeller to the aircraft frame. By designing the conductive portion to perform multiple necessary functions, propeller design can be simplified while reducing component weight and number.

[0187] Furthermore, although the magnet 1830 in the example embodiments of Figures 18A-18I has been described relative to a permanent magnet, the embodiments of this disclosure are not limited thereto. In some embodiments, the magnet 1830 in the above configuration may include an electromagnet. For example, Figures 18J and 18K schematically illustrate example embodiments in which the magnet 1830 includes an electromagnet. The example configuration may correspond to, for example, the configuration shown in Figure 18G. In some embodiments, the electromagnet may include a coil, such as an air-core coil or an iron-core coil, connected to a power source. The power source may include, for example, a portion of motor assembly 1802, such as an inverter or a sub-control module (not shown).

[0188] In some embodiments, as shown in FIG18J, the coil may be connected to a DC power circuit 1840. For example, in some embodiments, the DC power circuit may include a buck converter circuit. The DC power circuit 1840 may resemble the magnetic field of a stationary permanent magnet. However, unlike the permanent magnet described above, the electromagnet 1830 may operate selectively only when needed, thereby allowing the propeller to operate at optimal efficiency under other conditions. Furthermore, the amplitude of the magnetic field can be adjusted to generate the required amount of heat.

[0189] However, a drawback of the permanent magnets and DC-powered electromagnets discussed above is that both may require relative motion between the magnet 1830 and the conductive portion 1831 to generate eddy current heating or drive current through the wiring path 1817. Therefore, in some embodiments, as seen in Figure 18K, the electromagnet 1830 may include a coil connected to the AC power circuit 1841. In some embodiments, the conductive portion 1831 may include a similar induction coil as shown, or may include the windings or sheet metal discussed earlier. Eddy current heating or induced current can be generated because the AC power circuit produces a varying magnetic field, even when the propeller is stationary. This can be advantageous for de-icing, for example, when the aircraft is grounded. This can be particularly advantageous for lift propellers that can be stably retracted during cruise flight in icing conditions. The AC power circuit 1841 can be configured to adjust both the amplitude and frequency of the magnetic field to regulate the heating and current parameters.

[0190] A non-transitory computer-readable medium may be provided, which stores instructions for one or more processors of a controller to perform ice management embodiments of the present disclosure. For example, the instructions stored in the non-transitory computer-readable medium may be executed by the circuitry of the controller to perform some or all of the ice management processes disclosed above. Common forms of non-transitory media include, for example, floppy disks, hard disks, solid-state drives, magnetic tape or any other magnetic data storage media, compact optical disc read-only memory (CD-ROM), any other optical data storage media, any physical media with a perforated pattern, 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), cache memory, registers, any other memory chips or memory cartridges, and network versions of the above memories. The one or more processors may comprise 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), general-purpose array logic (GALs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), system-on-a-chip (SoCs), application-specific integrated circuits (ASICs), and any combination thereof. In some embodiments, the one or more processors may also be a group of processors grouped by a single logic component.

[0191] Embodiments of this disclosure may be further described with respect to the following terms: 1. A flight control system for an aircraft, the flight control system comprising: a memory storing instructions; and a processor configured to execute the instructions to perform operations including: determining an icing condition based on an icing condition input; determining an aircraft state based on one or more predefined flight parameters; determining propeller adjustment parameters based on the icing condition and the aircraft state; generating a plurality of actuator commands corresponding to the propeller adjustment parameters, wherein the plurality of actuator commands are configured to induce a first ice management cycle in a first symmetrical propeller pair of the aircraft and a second ice management cycle in a second symmetrical propeller pair of the aircraft, the first ice management cycle occurring over a first time interval different from a second time interval of the second ice management cycle.

[0192] 2. The flight control system according to Clause 1, wherein the icing status input is based on the main icing detector.

[0193] 3. The flight control system according to Clause 1 or 2, wherein the icing status input is based on input from the flight control system or from the pilot.

[0194] 4. A flight control system according to any one of Clauses 1 to 3, wherein the one or more predefined parameters include one of control margin state, current roll angle, load factor, vertical airspeed and commanded airspeed, altitude, propulsion system, signal integrity or flight mode.

[0195] 5. The flight control system according to any one of Clauses 1 to 4, wherein the propeller adjustment parameters include one of revolutions per minute (RPM), pitch angle, torque, or propeller tilt angle.

[0196] 6. The flight control system according to any one of Clauses 1 to 5, wherein the propeller adjustment parameters include RPM, and the first ice management cycle includes increasing the RPM of the first symmetrical propeller pair by at least 50% during the first time interval.

[0197] 7. The flight control system according to any one of Clauses 1 to 5, wherein the propeller adjustment parameters include RPM, and the first ice management cycle includes increasing the RPM of the first symmetrical propeller pair to at least 80% of the maximum RPM during the first time interval.

[0198] 8. The flight control system according to any one of Clauses 1 to 5, wherein the propeller adjustment parameters include the pitch angle, and the first ice management cycle includes changing the pitch angle of the first symmetrical propeller pair by at least 5 degrees during the first time interval.

[0199] 9. The flight control system according to Clause 8, wherein the first ice management cycle further includes changing the pitch angle of the first symmetrical propeller pair by at least 5 degrees at least four times during the first time interval.

[0200] 10. The flight control system according to any one of clauses 1 to 9, wherein the propeller adjustment parameters include torque, and the first ice management cycle includes changing the torque of the first symmetrical propeller pair by at least 50% during the first time interval.

[0201] 11. The flight control system according to any one of clauses 1 to 9, wherein the propeller adjustment parameters include torque, and the first ice management cycle comprises: increasing the torque of the first symmetrical propeller pair from an initial torque value to within 80% of the maximum torque during the first time interval, and decreasing the torque of the first symmetrical propeller pair to the initial torque.

[0202] 12. The flight control system according to any one of Clauses 1 to 11, wherein the propeller adjustment parameters include a propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of the first symmetrical propeller pair by at least 10 degrees during the first time interval.

[0203] 13. A flight control system according to any one of clauses 1 to 5 or 8 to 12, wherein the propeller adjustment parameters include RPM, and the first ice management cycle includes increasing the first RPM of the first symmetrical propeller pair to at least 80% of the second RPM of the second symmetrical propeller pair during the first time interval.

[0204] 14. The flight control system according to Clause 13, wherein the first ice management cycle further includes reducing the second RPM of the second symmetrical propeller pair during the first time interval to compensate for the increased RPM of the first symmetrical propeller pair.

[0205] 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 symmetrical propeller pair to at least 80% of the first RPM of the first symmetrical propeller pair during the second time interval.

[0206] 16. The flight control system according to any one of Clauses 13 to 15, wherein the second ice management cycle further includes reducing the first RPM of the first symmetrical propeller pair during the second time interval to compensate for the increased RPM of the second symmetrical propeller pair.

[0207] 17. A flight control system according to any one of clauses 1 to 7 or 10 to 16, wherein the propeller adjustment parameters include a pitch angle, and the first ice management cycle includes changing the first pitch angle of the first symmetrical propeller pair relative to the second pitch angle of the second symmetrical propeller pair by at least 5 degrees during the first time interval.

[0208] 18. The flight control system according to Clause 17, wherein the first ice management cycle further includes increasing the second RPM of the second symmetrical propeller pair during the first time interval.

[0209] 19. The flight control system according to Clause 17 or 18, wherein the second ice management cycle includes changing the second pitch angle of the second symmetrical propeller pair relative to the first pitch angle of the first symmetrical propeller pair by at least 5 degrees during the second time interval.

[0210] 20. A flight control system according to any one of clauses 1 to 9 or 12 to 19, wherein the propeller adjustment parameters include torque, and the first ice management cycle includes increasing the torque of the first symmetrical propeller pair from an initial torque value to a first torque value, and decreasing the torque of the first symmetrical propeller pair from the first torque value to a second torque value.

[0211] 21. The flight control system according to Clause 20, wherein the first torque value is within 80% of the maximum torque value of the first symmetrical propeller pair.

[0212] 22. The flight control system according to clause 20 or 21, wherein the second torque value is less than 50% of the initial torque value of the first symmetrical propeller pair.

[0213] 23. The flight control system according to any one of Clauses 20 to 22, wherein the first ice management cycle further includes increasing the second RPM of the second symmetrical propeller pair during the first time interval.

[0214] 24. The flight control system according to any one of clauses 1 to 23, wherein the propeller adjustment parameters include a propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of the first symmetrical propeller pair by at least 10 degrees.

[0215] 25. The flight control system according to Clause 24, wherein the first ice management cycle further includes increasing the second RPM of the second symmetrical propeller pair during the first time interval.

[0216] 26. The flight control system according to any one of clauses 1 to 25, wherein the first symmetrical propeller pair includes a first outermost propeller from a first side of the body of the aircraft and a second outermost propeller from a second side of the body of the aircraft.

[0217] 27. The flight control system according to Clause 26, wherein the second symmetrical propeller pair includes a third propeller located on the first side of the body of the aircraft, extending inward from the first propeller, and a fourth propeller located on the second side of the body of the aircraft, extending inward from the second propeller.

[0218] 28. The flight control system according to Clause 27, wherein the plurality of actuator commands are further configured to induce a third ice management cycle in the third symmetrical propeller pair of the aircraft, 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.

[0219] 29. The flight control system according to Clause 28, wherein the third symmetrical propeller pair includes a fifth propeller located on the first side of the body of the aircraft between the first propeller and the third propeller, and a sixth propeller located on the second side of the body of the aircraft between the second propeller and the fourth propeller.

[0220] 30. A flight control system according to any one of clauses 1 to 29, wherein the flight control system is configured to generate the plurality of actuator commands in repeating time intervals.

[0221] 31. The flight control system according to any one of clauses 1 to 30, wherein the plurality of actuator commands are configured to cause the first ice management cycle and the second ice management cycle in non-overlapping time intervals.

[0222] 32. The flight control system according to any one of clauses 1 to 31, wherein the first symmetrical propeller pair and the second symmetrical propeller pair include a tilting propeller pair.

[0223] 33. The flight control system according to any one of Clauses 1 to 32, wherein the first ice management cycle further comprises: rotating a symmetrical lift propeller pair between a first angular position and a second angular position, the first angular position being offset by a multiple of 30 degrees relative to the second angular position.

[0224] 34. The flight control system according to Clause 33, wherein, in the forward flight direction, each lift propeller of the symmetrical lift propeller pair is located behind the corresponding tilt propeller of the first symmetrical tilt propeller pair.

[0225] 35. The flight control system according to clause 33 or 34, wherein each lift propeller in the symmetrical lift propeller pair is positioned further away from the body of the aircraft than the corresponding tilt propeller in the first symmetrical tilt propeller pair.

[0226] 36. The flight control system according to any one of clauses 32 to 35, wherein each of the symmetrical lift propeller pairs is positioned closer to the body of the aircraft than the corresponding tilt propeller in the first symmetrical tilt propeller pair.

[0227] 37. The flight control system according to any one of Clauses 1 to 31, wherein the first symmetrical propeller pair and the second symmetrical propeller pair comprise a lift propeller pair.

[0228] 38. The flight control system according to Clause 37, wherein the first ice management cycle comprises: rotating the first symmetrical propeller pair between a first angular position and a second angular position, the first angular position being offset by a multiple of 30 degrees relative to the second angular position.

[0229] 39. The flight control system according to Clause 38, wherein rotating the first symmetrical propeller pair comprises rotating the first lift propeller of the first symmetrical propeller pair in a direction opposite to that of the second lift propeller of the first symmetrical propeller pair.

[0230] 40. A flight control system according to any one of clauses 1 to 39, wherein the plurality of actuator commands are configured to execute the first ice management cycle in periodic intervals based on a predetermined schedule to manage asymmetric icing.

[0231] 41. A flight control system according to any one of clauses 1 to 40, wherein the flight control system is configured to generate the plurality of actuator commands in periodic intervals to manage asymmetric icing.

[0232] 42. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller; a motor assembly coupled to the propeller; a heat exchanger; an oil flow path configured to thermally couple the heat exchanger to the motor assembly, the oil flow path including a first segment, a second segment, and a third segment; and a cabin mechanically coupled to the motor assembly, the cabin including an air inlet configured to direct air into the heat exchanger, the air inlet including a lower lip configured relative to forward flight and an upper lip opposite the lower lip, the lower lip being further away from the motor assembly than the upper lip, wherein: the first segment passes through the motor assembly; the second segment passes through the heat exchanger; the third segment passes along the lower lip; and the oil flow path bypasses the upper lip.

[0233] 43. The propeller assembly according to clause 42, further comprising: a thermally conductive material located between the motor assembly and the upper lip, the thermally conductive material being configured to conduct heat from the motor assembly to the upper lip.

[0234] 44. The propeller assembly according to clause 43, wherein: the hull comprises a first material; the thermally conductive material comprises a second material, the second material being different from the first material; and the thermal conductivity of the second material is higher than that of the first material.

[0235] 45. The propeller assembly according to clause 43 or 44, wherein the thermally conductive material extends along two sides of the air inlet located between the upper lip and the lower lip.

[0236] 46. ​​The propeller assembly according to any one of clauses 43 to 45, wherein the thermally conductive material extends from the interior of the motor assembly to the exterior of the motor assembly.

[0237] 47. The propeller assembly according to clause 46, wherein the thermally conductive material comprises a plate extending from the interior of the motor assembly to the exterior of the motor assembly.

[0238] 48. The propeller assembly according to any one of clauses 43 to 47, wherein the thermally conductive material is wrapped around the motor assembly.

[0239] 49. The propeller assembly according to any one of clauses 42 to 48, wherein the third segment branches off from the second segment in the direction of oil flow and returns to the second segment in the direction of oil flow.

[0240] 50. The propeller assembly according to Clause 49, wherein the first section is fed into the second section in the direction of oil flow and returns from the second section in the direction of oil flow.

[0241] 51. The propeller assembly according to any one of clauses 42 to 50, further comprising a first flow control valve configured to adjust the oil flow rate through the third section.

[0242] 52. The propeller assembly according to Clause 51, wherein the first flow control valve is configured to selectively shut off oil flow into or from the third section.

[0243] 53. The propeller assembly according to clause 51 or 52 further includes a second flow control valve, wherein the first flow control valve is located at the inlet side of the third section, and the second flow control valve is located at the outlet side of the third section.

[0244] 54. The propeller assembly according to any one of clauses 42 to 53, wherein the third segment extends along the lower surface of the cabin relative to the forward-flying configuration.

[0245] 55. The propeller assembly according to any one of clauses 42 to 54, wherein the third section branches off from the first section at the outlet point of the first section along the direction of oil flow.

[0246] 56. The propeller assembly according to Clause 55, wherein the third section is fed into the second section in the direction of oil flow.

[0247] 57. The propeller assembly according to clause 55 or 56, wherein the third segment returns to the first segment at the first segment entry point along the oil flow direction, the first segment entry point being downstream of the first segment exit point in the oil flow direction.

[0248] 58. The propeller assembly according to Clause 57, wherein the first entry point is located upstream of the second entry point in the direction of oil flow.

[0249] 59. The propeller assembly according to Clause 57, wherein the first entry point is located downstream of the second entry point in the direction of oil flow.

[0250] 60. The propeller assembly according to any one of clauses 42 to 59, wherein the third segment is connected in series within the first segment.

[0251] 61. The propeller assembly according to any one of clauses 42 to 60, wherein a first portion of the first segment is fed into the third segment, and the third segment is fed into a second portion of the first segment.

[0252] 62. The propeller assembly according to any one of clauses 42 to 61, wherein a first portion of the first segment is fed into the third segment, and the third segment is fed into a second portion of the first segment.

[0253] 63. A vertical takeoff and landing (VTOL) aircraft comprising a propeller assembly according to any one of clauses 42 to 62, wherein the propeller, the motor assembly, the heat exchanger, and the cabin are configured to tilt relative to the frame of the VTOL aircraft between a lift configuration and a cruise configuration.

[0254] 64. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller; a motor assembly coupled to the propeller; a heat exchanger; an oil flow path configured to thermally couple the heat exchanger to the motor assembly, the oil flow path including a first section and a second section; a cabin mechanically coupled to the motor assembly, the cabin including an air inlet configured to direct air into the heat exchanger, the air inlet including a lower lip configured relative to a forward-flying configuration and an upper lip opposite the lower lip, the lower lip being further away from the motor assembly than the upper lip; and a heat pipe circuit configured to collect heat from a heat source and discharge the heat to the lower lip, wherein: the first section passes through the motor assembly and the second section passes through the heat exchanger.

[0255] 65. The propeller assembly according to Clause 64, wherein the heat source includes the motor assembly.

[0256] 66. The propeller assembly according to clause 64 or 65, wherein the heat source comprises a thermally conductive material located between the motor assembly and the hull.

[0257] 67. The propeller assembly according to any one of clauses 64 to 66, wherein the heat source includes the heat exchanger.

[0258] 68. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller; a motor assembly coupled to the propeller; a heat exchanger; an oil flow path configured to thermally couple the heat exchanger to the motor assembly, the oil flow path passing through the motor assembly and the heat exchanger; a cabin mechanically coupled to the motor assembly, the cabin including an air inlet; wherein the heat exchanger is disposed at the air inlet.

[0259] 69. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller hub; propeller blades coupled to the propeller hub; a hub cover coupled to the propeller hub; a hub cover rod coupled to the propeller hub; a conductive portion; a motor configured to rotate the propeller hub, the propeller blades, the hub cover, the hub cover rod, and the conductive portion; and a magnet suspended on the hub cover rod, the magnet being rotatably decoupled from the hub cover rod by a bearing; wherein the magnet is configured to generate an electric current in the conductive portion when the propeller rotates to manage ice buildup on the surface of the propeller assembly.

[0260] 70. The propeller assembly according to clause 69, wherein: the conductive portion comprises a metal sheet; and the current comprises eddy currents for generating heat in the conductive portion.

[0261] 71. The propeller assembly according to clause 69 or 70, wherein the conductive portion includes windings; and the current generates an electrical flow in the conductive portion.

[0262] 72. The propeller assembly according to any one of clauses 69 to 71, wherein the conductive portion is located on the side portion of the hub cover.

[0263] 73. The propeller assembly according to any one of clauses 69 to 72, wherein the conductive portion is located at the front portion of the hub cover.

[0264] 74. The propeller assembly according to any one of clauses 69 to 73, wherein the conductive portion is located at the propeller hub.

[0265] 75. The propeller assembly according to any one of clauses 69 to 74, further comprising: a wiring path configured to conduct either heat or electricity from the conductive portion to at least one of the hub cover or the propeller blades.

[0266] 76. The propeller assembly according to Clause 75 further includes a switch configured to enable or disable the connection between the conductive portion and the wiring path.

[0267] 77. The propeller assembly according to Clause 76, wherein the switch includes a temperature control switch configured to disable the switch when the temperature at the switch reaches a predetermined temperature.

[0268] 78. The propeller assembly according to Clause 76, wherein the switch is configured to be controlled using wireless communication.

[0269] 79. The propeller assembly according to Clause 76, wherein the switch is configured to be powered by a current generated in the conductive portion.

[0270] 80. The propeller assembly according to any one of clauses 69 to 79, further comprising: a magnetic field sensor configured to detect the magnetic flux of the magnet and to transmit a signal to the motor based on the detection.

[0271] 81. The propeller assembly according to Clause 80, wherein the controller of the motor is configured to determine the rotational position of the propeller assembly based on the signal.

[0272] 82. The propeller assembly according to any one of clauses 69 to 81 further includes an additional magnet coupled to the bearing and arranged symmetrically with respect to the hub cap rod.

[0273] 83. The propeller assembly according to any one of clauses 69 to 82 further includes a plurality of magnets arranged symmetrically around the hub cap rod.

[0274] 84. The propeller assembly according to any one of clauses 69 to 83 further includes a counterweight configured to balance the magnet suspended on the hub cap rod.

[0275] 85. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller hub; propeller blades coupled to the propeller hub; a hub cap coupled to the propeller hub; a hub cap rod coupled to the propeller hub; a conductive portion coupled to the hub cap rod; a bearing surrounding the hub cap rod and configured to support a magnet array around the conductive portion; and a motor configured to rotate the propeller hub, the propeller blades, the hub cap, the hub cap rod, and the conductive portion; wherein the magnet array is configured to generate an electric current in the conductive portion when the propeller rotates to manage ice buildup on the surface of the propeller assembly.

[0276] 86. The propeller assembly according to Clause 85 further includes a counterweight configured to maintain the orientation of the bearing relative to the direction of gravity.

[0277] 87. A propeller assembly for an aircraft, the propeller assembly comprising: a rotating portion including: a propeller hub; propeller blades coupled to the propeller hub; a hub cover coupled to the propeller hub; and a conductive portion; a motor configured to rotate the rotating portion; and a magnet configured to remain stationary relative to the motor; wherein the magnet is configured to generate an electric current in the conductive portion when the rotating portion rotates to manage ice buildup on a surface of the rotating portion.

[0278] 88. The propeller assembly according to clause 87, wherein: the conductive portion comprises a metal sheet; and the current comprises eddy currents for generating heat in the conductive portion.

[0279] 89. The propeller assembly according to clause 87 or 88, wherein the conductive portion includes windings; and the current generates an electrical flow in the conductive portion.

[0280] 90. A propeller assembly according to any one of clauses 87 to 89, wherein the conductive portion is located at the propeller hub or at a propeller flange coupled to the propeller hub.

[0281] 91. The propeller assembly according to any one of clauses 87 to 90, wherein the conductive portion is located at the propeller blade.

[0282] 92. The propeller assembly according to any one of clauses 87 to 91, wherein the conductive portion includes structural supports for the propeller blades.

[0283] 93. The propeller assembly according to any one of clauses 87 to 92, wherein the conductive portion includes a lightning grounding path for the propeller blades.

[0284] 94. The propeller assembly according to any one of clauses 87 to 93, further comprising: a wiring path configured to conduct either heat or electricity from the conductive portion to at least one of the hub cover or the propeller blades.

[0285] 95. The propeller assembly according to Clause 94 further includes a switch configured to enable or disable the connection between the conductive portion and the wiring path.

[0286] 96. The propeller assembly according to Clause 95, wherein the switch includes a temperature control switch configured to disable the switch when the temperature at the switch reaches a predetermined temperature.

[0287] 97. The propeller assembly according to Clause 95, wherein the switch is configured to be controlled using wireless communication.

[0288] 98. The propeller assembly according to Clause 97, wherein the switch is configured to be powered by a current generated in the conductive portion.

[0289] 99. The propeller assembly according to any one of clauses 87 to 98, further comprising: a magnetic field sensor configured to detect the magnetic flux of the magnet and to transmit a signal to the motor based on the detection.

[0290] 100. The propeller assembly according to clause 99, wherein the controller of the motor is configured to determine the rotational position of the propeller assembly based on the signal.

[0291] 101. The propeller assembly according to any one of clauses 87 to 100, wherein the magnet comprises a permanent magnet.

[0292] 102. The propeller assembly according to any one of clauses 87 to 101, wherein the magnet comprises an electromagnet.

[0293] 103. The propeller assembly according to Clause 102 further includes a DC power circuit configured to provide DC power to the electromagnet.

[0294] 104. The propeller assembly according to Clause 102 further includes an AC power circuit configured to provide AC power to the electromagnet.

[0295] 105. The propeller assembly according to any one of clauses 87 to 104, wherein: the rotating portion further includes a propeller shaft coupled to the propeller hub and configured to rotate via the motor; the propeller assembly further includes a hub cover rod configured to pass through the propeller shaft and rotatably decoupled from the propeller shaft; wherein the magnet includes a first magnet mechanically coupled to the hub cover rod.

[0296] 106. The propeller assembly according to Clause 105 further includes a second magnet mechanically coupled to the hub cap rod at a position diametrically opposite to the position of the first magnet.

[0297] 107. The propeller assembly according to clause 105 or 106, further comprising: a pitch control, wherein the hub cap rod includes a pitch control lever configured to actuate the pitch control.

[0298] 108. The propeller assembly according to Clause 107, wherein the hub cap rod is rotatably decoupled from the pitch control via a bearing.

[0299] 109. The propeller assembly according to clause 107 or 108, wherein the pitch control includes a yoke and blade actuation pins.

[0300] 110. A method for managing icing on an aircraft, the method comprising: determining an icing condition of the aircraft; and performing propeller regulation based on the icing condition, wherein performing the propeller regulation comprises: inducing a first ice management cycle in a first symmetrical propeller pair of the aircraft, and inducing a second ice management cycle in a second symmetrical propeller pair of the aircraft, the first ice management cycle occurring over a first time interval, the first time interval being different from a second time interval of the second ice management cycle.

[0301] 111. The method according to Clause 110, wherein the determination of the icing condition is based on a main icing detector.

[0302] 112. The method according to Clause 110 or 111, wherein the determination of the icing condition is based on input from the flight control system or input from the pilot, the input indicating the presence of icing.

[0303] 113. The method according to any one of clauses 110 to 112 further comprises: determining an aircraft state; and performing the propeller adjustment when the aircraft state satisfies one or more predefined parameters.

[0304] 114. The method according to Clause 113, wherein the one or more predefined parameters include one of control margin state, current roll angle, load factor, vertical airspeed and command airspeed, altitude, propulsion system, signal integrity or flight mode.

[0305] 115. The method according to any one of clauses 110 to 114, wherein the propeller adjustment includes adjusting at least one of revolutions per minute (RPM), pitch angle, torque, or propeller tilt angle.

[0306] 116. The method according to any one of clauses 110 to 115, wherein the propeller adjustment includes adjusting the RPM, and the first ice management cycle includes increasing the RPM of the first symmetrical propeller pair by at least 50% during the first time interval.

[0307] 117. The method according to any one of clauses 110 to 115, wherein the propeller adjustment includes adjusting the RPM, and the first ice management cycle includes increasing the RPM of the first symmetrical propeller pair to at least 80% of the maximum RPM during the first time interval.

[0308] 118. The method according to any one of clauses 110 to 115, wherein the propeller adjustment includes adjusting the pitch angle, and the first ice management cycle includes changing the pitch angle of the first symmetrical propeller pair by at least 5 degrees during the first time interval.

[0309] 119. The method according to Clause 118, wherein the first ice management cycle further comprises changing the pitch angle of the first symmetrical propeller pair by at least 5 degrees at least four times during the first time interval.

[0310] 120. The method according to any one of clauses 110 to 119, wherein the propeller adjustment includes adjusting torque, and the first ice management cycle includes changing the torque of the first symmetrical propeller pair by at least 50% during the first time interval.

[0311] 121. The method according to any one of clauses 110 to 119, wherein the propeller adjustment includes adjusting torque, and the first ice management cycle includes: increasing the torque of the first symmetrical propeller pair from an initial torque value to within 80% of the maximum torque during the first time interval, and decreasing the torque of the first symmetrical propeller pair back to the initial torque.

[0312] 122. The method according to any one of clauses 110 to 121, wherein the propeller adjustment includes adjusting the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of the first symmetrical propeller pair by at least 10 degrees during the first time interval.

[0313] 123. The method according to any one of clauses 110 to 115 or 118 to 122, wherein the propeller adjustment includes adjusting the RPM, and the first ice management cycle includes increasing the first RPM of the first symmetrical propeller pair to at least 80% of the second RPM of the second symmetrical propeller pair during the first time interval.

[0314] 124. The method according to Clause 123, wherein the first ice management cycle further includes reducing the second RPM of the second symmetrical propeller pair during the first time interval to compensate for the increased RPM of the first symmetrical propeller pair.

[0315] 125. The method according to clause 123 or 124, wherein: the second ice management cycle includes increasing the second RPM of the second symmetrical propeller pair to at least 80% of the first RPM of the first symmetrical propeller pair during the second time interval.

[0316] 126. The method according to any one of clauses 123 to 125, wherein the second ice management cycle further comprises reducing the first RPM of the first symmetrical propeller pair during the second time interval to compensate for the increased RPM of the second symmetrical propeller pair.

[0317] 127. The method according to any one of clauses 110 to 117 or 120 to 126, wherein the propeller adjustment includes adjusting the pitch angle, and the first ice management cycle includes changing the first pitch angle of the first symmetrical propeller pair relative to the second pitch angle of the second symmetrical propeller pair by at least 5 degrees during the first time interval.

[0318] 128. The method according to Clause 127, wherein the first ice management cycle further includes increasing the second RPM of the second symmetrical propeller pair during the first time interval.

[0319] 129. The method according to Clause 127 or 128, wherein the second ice management cycle includes changing the second pitch angle of the second symmetrical propeller pair relative to the first pitch angle of the first symmetrical propeller pair by at least 5 degrees during the second time interval.

[0320] 130. The method according to any one of clauses 110 to 119 or 122 to 129, wherein the propeller adjustment includes adjusting torque, and the first ice management cycle includes increasing the torque of the first symmetrical propeller pair from an initial torque value to a first torque value, and decreasing the torque of the first symmetrical propeller pair from the first torque value to a second torque value.

[0321] 131. The method according to Clause 130, wherein the first torque value is within 80% of the maximum torque value of the first symmetrical propeller pair.

[0322] 132. The method according to clause 130 or 131, wherein the second torque value is less than 50% of the initial torque value of the first symmetrical propeller pair.

[0323] 133. The method according to any one of clauses 130 to 132, wherein the first ice management cycle further includes increasing the second RPM of the second symmetrical propeller pair during the first time interval.

[0324] 134. The method according to any one of clauses 110 to 133, wherein the propeller adjustment includes adjusting the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of the first symmetrical propeller pair by at least 10 degrees.

[0325] 135. The method according to Clause 134, wherein the first ice management cycle further includes increasing the second RPM of the second symmetrical propeller pair during the first time interval.

[0326] 136. The method according to any one of clauses 110 to 135, wherein the first symmetrical propeller pair comprises a first outermost propeller from a first side of the body of the aircraft and a second outermost propeller from a second side of the body of the aircraft.

[0327] 137. The method according to Clause 136, wherein the second symmetrical propeller pair includes a third propeller located on the first side of the body of the aircraft, extending inward from the first propeller, and a fourth propeller located on the second side of the body of the aircraft, extending inward from the second propeller.

[0328] 138. The method according to Clause 137, wherein performing the propeller adjustment includes inducing a third ice management cycle in the third symmetrical propeller pair of the aircraft, 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.

[0329] 139. The method according to Clause 138, wherein the third symmetrical propeller pair includes a fifth propeller located on the first side of the body of the aircraft between the first propeller and the third propeller, and a sixth propeller located on the second side of the body of the aircraft between the second propeller and the fourth propeller.

[0330] 140. The method according to any one of clauses 110 to 139 further includes performing the propeller adjustment at repeated time intervals.

[0331] 141. The method according to any one of clauses 110 to 140, wherein performing the propeller regulation includes inducing the first ice management cycle and the second ice management cycle in non-overlapping time intervals.

[0332] 142. The method according to any one of clauses 110 to 141, wherein the first symmetrical propeller pair and the second symmetrical propeller pair include a tilting propeller pair.

[0333] 143. The method according to any one of clauses 110 to 142, wherein the first ice management cycle further comprises: rotating a pair of symmetrical lift propellers between a first angular position and a second angular position, the first angular position being offset by a multiple of 30 degrees relative to the second angular position.

[0334] 144. The method according to Clause 143, wherein, in the forward flight direction, each lift propeller of the symmetrical lift propeller pair is located behind the corresponding tilt propeller of the first symmetrical tilt propeller pair.

[0335] 145. The method according to clause 143 or 144, wherein each lift propeller in the symmetrical lift propeller pair is positioned further away from the body of the aircraft than the corresponding tilt propeller in the first symmetrical tilt propeller pair.

[0336] 146. The method according to any one of clauses 142 to 145, wherein each lift propeller in the symmetrical lift propeller pair is positioned closer to the body of the aircraft than the corresponding tilt propeller in the first symmetrical tilt propeller pair.

[0337] 147. The method according to any one of clauses 110 to 141, wherein the first symmetrical propeller pair and the second symmetrical propeller pair comprise a lift propeller pair.

[0338] 148. The method according to Clause 147, wherein the first ice management cycle comprises: rotating the first symmetrical propeller pair between a first angular position and a second angular position, the first angular position being offset by a multiple of 30 degrees relative to the second angular position.

[0339] 149. The method according to Clause 148, wherein rotating the first symmetrical propeller pair comprises rotating the first lift propeller of the first symmetrical propeller pair in a direction opposite to that of the second lift propeller of the first symmetrical propeller pair.

[0340] 150. The method according to any one of clauses 110 to 149, wherein performing the propeller regulation includes performing the first ice management cycle in periodic intervals based on a predetermined schedule to manage asymmetrical icing.

[0341] 151. The method according to any one of clauses 110 to 150 further includes performing the propeller adjustment in periodic intervals to manage asymmetrical icing.

[0342] 152. A computer-readable medium storing a set of instructions executable by at least one processor of a device to cause the device to perform a method according to any one of clauses 110 to 151.

[0343] 153. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller shaft; a propeller hub coupled to the propeller shaft; propeller blades coupled to the propeller hub; a hub cover coupled to the propeller hub; a conductive portion; a motor configured to rotate the propeller shaft, the propeller hub, the propeller blades, the hub cover, and the conductive portion; a hub cover rod configured to pass through the propeller shaft and be rotatably decoupled from the propeller shaft; and a first magnet attached to the hub cover rod; wherein the first magnet is configured to generate an electric current in the conductive portion when the propeller rotates to manage ice buildup on the surface of the propeller assembly.

[0344] 154. The propeller assembly according to Clause 153 further includes: a pitch control, wherein the hub cap rod includes a pitch control lever configured to actuate the pitch control.

[0345] 155. The propeller assembly as described in Clause 154, wherein the pitch control includes a yoke and blade actuation pins.

[0346] 156. The propeller assembly according to clause 154 or 155, wherein the hub cap rod is rotatably decoupled from the pitch control via a bearing.

[0347] 157. The propeller assembly according to any one of clauses 154 to 156, further comprising a second magnet attached to the hub cap rod at a position diametrically opposite to the position of the first magnet.

[0348] 158. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller including: a hub; and a plurality of propeller blades, each of the plurality of propeller blades including a blade channel located inside the propeller blade and configured to circulate fluid; a motor assembly configured to rotate the propeller about a rotation axis; and an oil flow path configured to circulate oil through the motor assembly and through each blade channel of the plurality of propeller blades to thermally couple the motor assembly to the plurality of propeller blades; wherein the propeller assembly is configured to transfer heat from the motor assembly to an external environment outside the propeller assembly via thermal conduction through the propeller blades.

[0349] 159. The propeller assembly according to Clause 158, wherein during operation of the propeller assembly, heat conduction through the propeller blades transfers at least 30% of the heat generated by the motor assembly to the external environment.

[0350] 160. The propeller assembly according to Clause 158, wherein during operation of the propeller assembly, heat conduction through the propeller blades transfers at least 50% of the heat generated by the motor assembly to the external environment.

[0351] 161. The propeller assembly according to any one of clauses 158 to 160, wherein: each of the plurality of propeller blades further includes a heat conductor configured to conduct heat from the blade passage to a portion of the propeller blade radially outward from the blade passage.

[0352] 162. The propeller assembly according to any one of clauses 158 to 161, wherein the blade passage extends radially outward through the blade, the extension distance not exceeding 70% of the blade radius measured from the axis of rotation.

[0353] 163. The propeller assembly according to any one of clauses 158 to 162, wherein the blade passage extends radially outward through the blade, the extension distance not exceeding 50% of the blade radius measured from the axis of rotation.

[0354] 164. The propeller assembly according to any one of clauses 158 to 163, wherein the blade passage extends radially outward through the blade, the extension distance not exceeding 30% of the blade radius measured from the axis of rotation.

[0355] 165. The propeller assembly according to any one of clauses 158 to 164, wherein: the propeller further includes a hub cover having a hub cover channel configured to circulate fluid; and the oil flow path is further configured to circulate oil through the hub cover channel to thermally couple the motor assembly to the hub cover.

[0356] 166. A propeller assembly for an aircraft, the propeller assembly comprising: a propeller including: a hub; and a plurality of propeller blades, each of the plurality of propeller blades including a blade passage located within the propeller blade and configured to circulate fluid; a motor assembly configured to rotate the propeller about a rotation axis; and an oil flow path configured to circulate oil through the motor assembly and through each blade passage of the plurality of propeller blades to thermally couple the motor assembly to the plurality of propeller blades; wherein the plurality of propeller blades includes a single heat exchanger for the motor assembly.

[0357] 167. The propeller assembly according to clause 166, wherein during operation of the propeller assembly, heat conduction through the propeller blades transfers at least 30% of the heat generated by the motor assembly to the external environment.

[0358] 168. The propeller assembly according to clause 166, wherein during operation of the propeller assembly, heat conduction through the propeller blades transfers at least 50% of the heat generated by the motor assembly to the external environment.

[0359] 169. The propeller assembly according to any one of clauses 166 to 168, wherein: each of the plurality of propeller blades further includes a heat conductor configured to conduct heat from the blade passage to a portion of the propeller blade radially outward from the blade passage.

[0360] 170. The propeller assembly according to any one of clauses 166 to 169, wherein the blade passage extends radially outward through the blade, the extension distance not exceeding 70% of the blade radius measured from the axis of rotation.

[0361] 171. The propeller assembly according to any one of clauses 166 to 170, wherein the blade passage extends radially outward through the blade, the extension distance not exceeding 50% of the blade radius measured from the axis of rotation.

[0362] 172. The propeller assembly according to any one of clauses 166 to 171, wherein the blade passage extends radially outward through the blade, the extension distance not exceeding 30% of the blade radius measured from the axis of rotation.

[0363] 173. The propeller assembly according to any one of clauses 166 to 172, wherein: the propeller further includes a hub cover having a hub cover channel configured to circulate fluid; and the oil flow path is further configured to circulate oil through the hub cover channel to thermally couple the motor assembly to the hub cover.

[0364] 174. A method for managing icing on an aircraft, the method comprising: determining an icing condition of the aircraft; and performing propeller regulation based on the icing condition, wherein performing the propeller regulation comprises: inducing a first ice management cycle in a first group of one or more propellers of the aircraft, inducing a second ice management cycle in a second group of one or more propellers of the aircraft, the first group of one or more propellers being different from the second group of one or more propellers, and the first ice management cycle occurring over a first time interval, the first time interval being different from a second time interval of the second ice management cycle.

[0365] 175. The method according to Clause 174, wherein the determination of the icing condition is based on a master icing detector.

[0366] 176. The method according to Clause 174 or 175, wherein the determination of the icing condition is based on input from the flight control system or input from the pilot, the input indicating the presence of icing.

[0367] 177. The method according to any one of clauses 174 to 176 further comprises: determining an aircraft state; and performing the propeller adjustment when the aircraft state satisfies one or more predefined parameters.

[0368] 178. The method according to Clause 177, wherein the one or more predefined parameters include one of control margin state, current roll angle, load factor, vertical airspeed and commanded airspeed, altitude, propulsion system, signal integrity or flight mode.

[0369] 179. The method according to any one of clauses 174 to 178, wherein the propeller adjustment includes adjusting at least one of revolutions per minute (RPM), pitch angle, torque, or propeller tilt angle.

[0370] 180. The method according to any one of clauses 174 to 179, wherein the propeller adjustment includes adjusting the RPM, and the first ice management cycle includes increasing the RPM of the first group of one or more propellers by at least 50% during the first time interval.

[0371] 181. The method according to any one of clauses 174 to 179, wherein the propeller adjustment includes adjusting the RPM, and the first ice management cycle includes increasing the RPM of the first group of one or more propellers to at least 80% of the maximum RPM during the first time interval.

[0372] 182. The method according to any one of clauses 174 to 179, wherein the propeller adjustment includes adjusting the pitch angle, and the first ice management cycle includes changing the pitch angle of the first group of one or more propellers by at least 5 degrees during the first time interval.

[0373] 183. The method according to Clause 182, wherein the first ice management cycle further comprises changing the pitch angle of the first group of one or more propellers by at least 5 degrees at least four times during the first time interval.

[0374] 184. The method according to any one of clauses 174 to 183, wherein the propeller adjustment includes adjusting torque, and the first ice management cycle includes changing the torque of the first group of one or more propellers by at least 50% during the first time interval.

[0375] 185. The method according to any one of clauses 174 to 183, wherein the propeller adjustment includes adjusting torque, and the first ice management cycle includes: increasing the torque of the first group of one or more propellers from an initial torque value to within 80% of the maximum torque during the first time interval, and decreasing the torque of the first group of one or more propellers back to the initial torque.

[0376] 186. The method according to any one of clauses 174 to 185, wherein the propeller adjustment includes adjusting the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of the first group of one or more propellers by at least 10 degrees during the first time interval.

[0377] 187. The method according to any one of clauses 174 to 179 or 182 to 185, wherein the propeller adjustment includes adjusting the RPM, and the first ice management cycle includes increasing the first RPM of the first group of one or more propellers to at least 80% of the second RPM of the second group of one or more propellers during the first time interval.

[0378] 188. The method according to Clause 187, wherein the first ice management cycle further includes reducing the second RPM of the second group of one or more propellers during the first time interval to compensate for the increased RPM of the first group of one or more propellers.

[0379] 189. The method according to clause 187 or 188, wherein: the second ice management cycle includes increasing the second RPM of the second group of one or more propellers to at least 80% of the first RPM of the first group of one or more propellers during the second time interval.

[0380] 190. The method according to any one of Clauses 187 to 189, wherein the second ice management cycle further comprises reducing the first RPM of the first group of one or more propellers during the second time interval to compensate for the increased RPM of the second group of one or more propellers.

[0381] 191. The method according to any one of clauses 174 to 181 or 184 to 190, wherein the propeller adjustment includes adjusting the pitch angle, and the first ice management cycle includes changing the first pitch angle of the first group of one or more propellers relative to the second pitch angle of the second group of one or more propellers by at least 5 degrees during the first time interval.

[0382] 192. The method according to Clause 191, wherein the first ice management cycle further includes increasing the second RPM of the second group of one or more propellers during the first time interval.

[0383] 193. The method according to Clause 191 or 192, wherein the second ice management cycle includes changing the second pitch angle of the second group of one or more propellers relative to the first pitch angle of the first group of one or more propellers by at least 5 degrees during the second time interval.

[0384] 194. The method according to any one of clauses 174 to 183 or 186 to 193, wherein the propeller adjustment includes adjusting torque, and the first ice management cycle includes increasing the torque of the first group of one or more propellers from an initial torque value to a first torque value, and decreasing the torque of the first group of one or more propellers from the first torque value to a second torque value.

[0385] 195. The method according to Clause 194, wherein the first torque value is within 80% of the maximum torque value of the first group of one or more propellers.

[0386] 196. The method according to clause 194 or 195, wherein the second torque value is less than 50% of the initial torque value of the first group of one or more propellers.

[0387] 197. The method according to any one of clauses 194 to 196, wherein the first ice management cycle further includes increasing the second RPM of the second group of one or more propellers during the first time interval.

[0388] 198. The method according to any one of clauses 174 to 197, wherein the propeller adjustment includes adjusting the propeller tilt angle, and the first ice management cycle includes changing the propeller tilt angle of the first group of one or more propellers by at least 10 degrees.

[0389] 199. The method according to Clause 198, wherein the first ice management cycle further includes increasing the second RPM of the second group of one or more propellers during the first time interval.

[0390] 200. The method according to any one of clauses 174 to 199, wherein: the first group of one or more propellers comprises an outermost propeller from a first side of the body of the aircraft and an outermost propeller from a second side of the body of the aircraft, thereby forming a first symmetrical propeller pair.

[0391] 201. The method according to Clause 200, wherein: the second group of one or more propellers comprises an innermost propeller extending inward from the outermost propeller located on the first side of the body of the aircraft and an innermost propeller extending inward from the outermost propeller located on the second side of the body of the aircraft, thereby forming a second symmetrical propeller pair.

[0392] 202. The method according to Clause 201, wherein performing the propeller adjustment includes inducing a third ice management cycle in the third symmetrical propeller pair of the aircraft, 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.

[0393] 203. The method according to Clause 202, wherein the third symmetrical propeller pair comprises an intermediate propeller between the outermost propeller and the innermost propeller located on the first side of the body of the aircraft, and an intermediate propeller between the outermost propeller and the innermost propeller located on the second side of the body of the aircraft.

[0394] 204. The method according to any one of clauses 174 to 203 further includes performing the propeller adjustment at repeated time intervals.

[0395] 205. The method according to any one of clauses 174 to 204, wherein performing the propeller regulation includes inducing the first ice management cycle and the second ice management cycle in non-overlapping time intervals.

[0396] 206. The method according to any one of clauses 174 to 205, wherein the first group of one or more propellers and the second group of one or more propellers include tilting propellers.

[0397] 207. The method according to any one of clauses 174 to 206, wherein the first ice management cycle further comprises: rotating the lift propeller between a first angular position and a second angular position, the first angular position being offset by a multiple of 30 degrees relative to the second angular position.

[0398] 208. The method according to Clause 207, wherein, in the forward flight direction, the lift propeller is positioned behind one of the propellers in the first group of one or more propellers.

[0399] 209. The method according to Clause 207, wherein the lifting propeller is positioned further away from the body of the aircraft than one of the propellers in the first group of one or more propellers.

[0400] 210. The method according to any one of clauses 207 to 209, wherein the lifting propeller is positioned closer to the body of the aircraft than one of the propellers in the first group of one or more propellers.

[0401] 211. The method according to any one of clauses 174 to 205, wherein the first group of one or more propellers and the second group of one or more propellers comprise lift propellers.

[0402] 212. The method according to Clause 211, wherein the first ice management cycle includes rotating a first lift propeller of the first group of one or more propellers between a first angular position and a second angular position, the first angular position being offset by a multiple of 30 degrees relative to the second angular position.

[0403] 213. The method according to Clause 212, wherein the first ice management cycle includes rotating a second lift propeller in the first group of one or more propellers in a direction opposite to that of the first lift propeller.

[0404] 214. The method according to any one of clauses 174 to 213, wherein performing the propeller regulation includes performing the first ice management cycle in periodic intervals based on a predetermined schedule to manage asymmetrical icing.

[0405] 215. The method according to any one of clauses 174 to 214 further includes performing the propeller adjustment in periodic intervals to manage asymmetrical icing.

[0406] 216. A computer-readable medium storing a set of instructions executable by at least one processor of a device to cause the device to perform a method according to any one of clauses 174 to 215.

[0407] 217. A flight control system for an aircraft, the flight control system comprising: a memory storing instructions; and a processor configured to execute the instructions to cause the flight control system to perform a method according to any one of clauses 174 to 215.

[0408] 218. A method for managing icing on an aircraft, the method comprising: determining an icing condition of the aircraft; and performing propeller adjustment based on the icing condition, wherein performing the propeller adjustment comprises: adjusting a first propeller parameter of a first group of one or more propellers of the aircraft, and cooperatingly adjusting a second propeller parameter of the first group of one or more propellers of the aircraft, wherein the first propeller parameter and the second propeller parameter are different parameters, each of the first propeller parameter and the second propeller parameter of the first group of one or more propellers comprising one of: revolutions per minute (RPM), pitch angle, torque, propeller tilt angle, or propeller angular position about a propeller blade rotation axis.

[0409] 219. The method according to Clause 218, wherein one of the first propeller parameters or the second propeller parameters includes RPM.

[0410] 220. The method according to clause 218 or 219, wherein performing the propeller adjustment includes increasing the RPM of the first group of one or more propellers by at least 50%.

[0411] 221. The method according to any one of clauses 218 to 220, wherein performing the propeller adjustment includes increasing the RPM of the first group of one or more propellers to at least 80% of the maximum RPM.

[0412] 222. The method according to any one of clauses 218 to 221, wherein one of the first propeller parameters or the second propeller parameters includes a pitch angle.

[0413] 223. The method according to any one of clauses 218 to 222, wherein performing the propeller adjustment includes changing the pitch angle of the first group of one or more propellers by at least 5 degrees.

[0414] 224. The method according to any one of clauses 218 to 223, wherein one of the first propeller parameters or the second propeller parameters includes torque.

[0415] 225. The method according to any one of clauses 218 to 224, wherein performing the propeller adjustment comprises repeatedly braking and accelerating the first group of one or more propellers to induce vibrations in the propeller blades of the first group of one or more propellers.

[0416] 226. The method according to any one of clauses 218 to 225, wherein one of the first propeller parameters or the second propeller parameters includes a propeller tilt angle.

[0417] 227. The method according to any one of clauses 218 to 226, wherein performing the propeller adjustment includes changing the propeller tilt angle of the first group of one or more propellers by at least 10 degrees during a first time interval.

[0418] 228. The method according to any one of clauses 218 to 227, wherein one of the first propeller parameters or the second propeller parameters includes a propeller angular position about the axis of rotation of the propeller blades.

[0419] 229. The method according to any one of clauses 218 to 228, wherein: one of the first propeller parameters or the second propeller parameters includes a propeller angular position about a rotation axis of the propeller blades, wherein adjusting the propeller angular position includes moving at least one propeller of the first group of one or more propellers from a first angular position to a second angular position, the at least one propeller including at least a first blade and a second blade; wherein in the first angular position, a first surface of one of the first blades or the second blades faces away from the forward airflow, and a second surface of one of the first blades or the second blades faces the forward airflow, and in the second angular position, the second surface faces away from the forward airflow, and the first surface faces the forward airflow.

[0420] 230. The method according to Clause 229, wherein the first surface includes the tip of the first blade, and the second surface includes the tip of the second blade.

[0421] 231. The method according to Clause 229, wherein the first surface includes the leading edge of the first blade, and the second surface includes the trailing edge of the first blade.

[0422] 232. The method according to Clause 229, wherein the first surface includes the leading edge of the first blade, and the second surface includes the leading edge of the second blade.

[0423] 233. The method according to Clause 229, wherein the first surface includes the trailing edge of the first blade, and the second surface includes the trailing edge of the second blade.

[0424] 234. The method according to Clause 229, wherein the at least one propeller includes a tilting propeller, and another of the first propeller parameter or the second propeller parameter includes a propeller tilt angle.

[0425] 235. The method according to Clause 229, wherein the at least one propeller comprises a lift propeller or a tilting propeller, and another of the first propeller parameters or the second propeller parameters comprises propeller torque.

[0426] 236. The method according to any one of clauses 218 to 235, wherein adjusting the second propeller parameter is configured to compensate for the effect of adjusting the first propeller parameter on flight characteristics.

[0427] 237. The method according to any one of clauses 218 to 236, wherein adjusting the second propeller parameters is configured to perform ice management together with adjusting the first propeller parameters.

[0428] 238. The method according to any one of clauses 218 to 237, wherein performing the propeller adjustment further comprises: adjusting a third propeller parameter of a second group or more propellers of the aircraft to compensate for the effect of adjusting the first propeller parameter on flight characteristics, the second group being different from the first group; wherein the third propeller parameter includes one of the following: RPM, pitch angle, torque, propeller tilt angle, or propeller angular position about the axis of rotation of the propeller blades of the second group or more propellers.

[0429] 239. The method according to Clause 238, wherein the third propeller parameters are the same as the first propeller parameters.

[0430] 240. The method according to Clause 238, wherein the third propeller parameters are different from the first propeller parameters.

[0431] 241. The method according to any one of clauses 218 to 240, wherein the first group of one or more propellers includes at least one propeller on either side of the fuselage of the aircraft.

[0432] 242. The method according to any one of clauses 218 to 241, wherein the first group of one or more propellers comprises all the tilt propellers of the aircraft.

[0433] 243. The method according to any one of clauses 218 to 242, wherein the determination of the icing condition is based on a main icing detector.

[0434] 244. The method according to any one of clauses 218 to 243, wherein the determination of the icing condition is based on input from the flight control system or input from the pilot, the input indicating the presence of icing conditions.

[0435] 245. The method according to any one of clauses 218 to 244 further comprises: determining an aircraft state; and performing the propeller adjustment when the aircraft state satisfies one or more predefined parameters.

[0436] 246. The method according to Clause 245, wherein the one or more predefined parameters include one of control margin state, current roll angle, load factor, vertical airspeed and commanded airspeed, altitude, propulsion system, signal integrity or flight mode.

[0437] 247. A computer-readable medium storing a set of instructions executable by at least one processor of a device to cause the device to perform a method according to any one of clauses 218 to 246.

[0438] 248. A flight control system comprising: a memory storing instructions; and a processor configured to execute the instructions to cause the flight control system to perform a method according to any one of clauses 218 to 246.

[0439] 249. A method for managing icing on an aircraft, the method comprising: determining an icing condition of the aircraft; and performing propeller adjustment on one or more propellers based on the icing condition, wherein performing the propeller adjustment comprises: moving at least one propeller of a first group of one or more propellers from a first angular position to a second angular position, the at least one propeller including at least a first blade and a second blade; wherein in the first angular position, a first surface of one of the first blades or the second blade faces away from a forward airflow, and a second surface of one of the first blades or the second blade faces the forward airflow, and in the second angular position, the second surface faces away from the forward airflow, and the first surface faces the forward airflow.

[0440] 250. The method according to Clause 249, wherein the first surface includes the tip of the first blade, and the second surface includes the tip of the second blade.

[0441] 251. The method according to Clause 249, wherein the first surface includes the leading edge of the first blade, and the second surface includes the trailing edge of the first blade.

[0442] 252. The method according to Clause 249, wherein the first surface includes the leading edge of the first blade, and the second surface includes the leading edge of the second blade.

[0443] 253. The method according to Clause 249, wherein the first surface includes the trailing edge of the first blade, and the second surface includes the trailing edge of the second blade.

[0444] 254. The method according to any one of clauses 249 to 253, wherein the at least one propeller comprises a tilting propeller.

[0445] 255. The method according to any one of clauses 249 to 253, wherein the at least one propeller comprises a lift propeller.

[0446] 256. A computer-readable medium storing a set of instructions executable by at least one processor of a device to cause the device to perform a method according to any one of clauses 249 to 255.

[0447] 257. A flight control system comprising: a memory storing instructions; and a processor configured to execute the instructions to cause the flight control system to perform a method according to any one of clauses 249 to 256.

[0448] The foregoing description has been presented for illustrative purposes. This description is not exhaustive and does not limit the invention to the precise forms or embodiments disclosed herein. Modifications and adaptations to the invention will be apparent to those skilled in the art upon consideration of the specification and practice of the disclosed embodiments thereof.

Claims

1. A method for managing icing on an aircraft, the method comprising: Determine the icing status of the aircraft; And to perform propeller adjustment based on the icing conditions, wherein performing the propeller adjustment includes: adjusting a first propeller parameter of a first group of one or more propellers of the aircraft, and cooperatingly adjusting a second propeller parameter of the first group of one or more propellers of the aircraft, wherein the first propeller parameter and the second propeller parameter are different parameters, each including one of the following: revolutions per minute (RPM), pitch angle, torque, propeller tilt angle, or propeller angular position about the axis of rotation of the propeller blades of the first group of one or more propellers.

2. The method according to claim 1, wherein one of the first propeller parameters or the second propeller parameters includes RPM.

3. The method of claim 2, wherein performing the propeller adjustment comprises increasing the RPM of the first group of one or more propellers by at least 50%.

4. The method of claim 2 or 3, wherein performing the propeller adjustment comprises increasing the RPM of the first group of one or more propellers to at least 80% of the maximum RPM.

5. The method according to any one of claims 1 to 4, wherein one of the first propeller parameters or the second propeller parameters includes a pitch angle.

6. The method of claim 5, wherein performing the propeller adjustment comprises changing the pitch angle of the first group of one or more propellers by at least 5 degrees.

7. The method according to any one of claims 1 to 6, wherein one of the first propeller parameters or the second propeller parameters includes torque.

8. The method of claim 7, wherein performing the propeller adjustment comprises repeatedly braking and accelerating the first group of one or more propellers to induce vibration in the propeller blades of the first group of one or more propellers.

9. The method according to any one of claims 1 to 8, wherein one of the first propeller parameters or the second propeller parameters includes a propeller tilt angle.

10. The method according to any one of claims 1 to 9, wherein performing the propeller adjustment includes changing the propeller tilt angle of the first group of one or more propellers by at least 10 degrees during a first time interval.

11. The method according to any one of claims 1 to 10, wherein one of the first propeller parameters or the second propeller parameters includes the propeller angular position about the axis of rotation of the propeller blades.

12. The method according to claim 11, wherein: The first propeller parameter or the second propeller parameter includes a propeller angular position about the axis of rotation of the propeller blade, wherein adjusting the propeller angular position includes moving at least one propeller of the first group of one or more propellers from a first angular position to a second angular position, the at least one propeller including at least a first blade and a second blade; wherein in the first angular position, a first surface of one of the first blades or the second blade faces away from the forward airflow, and a second surface of one of the first blades or the second blade faces the forward airflow, and in the second angular position, the second surface faces away from the forward airflow, and the first surface faces the forward airflow.

13. The method of claim 12, wherein the first surface includes the tip of the first blade, and the second surface includes the tip of the second blade.

14. The method of claim 12, wherein the first surface includes the leading edge of the first blade, and the second surface includes the trailing edge of the first blade.

15. The method of claim 12, wherein the first surface includes the leading edge of the first blade, and the second surface includes the leading edge of the second blade.

16. The method of claim 12, wherein the first surface includes the trailing edge of the first blade, and the second surface includes the trailing edge of the second blade.

17. The method of claim 12, wherein the at least one propeller comprises a tilting propeller, and another of the first propeller parameter or the second propeller parameter comprises a propeller tilt angle.

18. The method of claim 12, wherein the at least one propeller comprises a lift propeller or a tilting propeller, and another of the first propeller parameters or the second propeller parameters comprises propeller torque.

19. The method according to any one of claims 1 to 18, wherein adjusting the second propeller parameter is configured to compensate for the effect of adjusting the first propeller parameter on flight characteristics.

20. The method according to any one of claims 1 to 19, wherein adjusting the second propeller parameters is configured to perform ice management together with adjusting the first propeller parameters.

21. The method according to any one of claims 1 to 20, wherein performing the propeller adjustment further comprises: Adjusting the third propeller parameters of one or more propellers in the second group of the aircraft to compensate for the effect of adjusting the first propeller parameters on flight characteristics, wherein the second group is different from the first group; The third propeller parameter includes one of the following: the RPM, pitch angle, torque, propeller tilt angle, or propeller angular position about the axis of rotation of the propeller blades of one or more propellers in the second group.

22. The method of claim 21, wherein the third propeller parameters are the same as the first propeller parameters.

23. The method of claim 21, wherein the third propeller parameters are different from the first propeller parameters.

24. The method according to any one of claims 1 to 23, wherein the determination of the icing condition is based on a main icing detector.

25. The method according to any one of claims 1 to 24, wherein the determination of the icing condition is based on input from the flight control system or input from the pilot, the input indicating the presence of icing.

26. The method according to any one of claims 1 to 25, further comprising: Determine the aircraft status; And when the aircraft state meets one or more predefined parameters, the propeller adjustment is performed.

27. The method of claim 26, wherein the one or more predefined parameters include one of control margin state, current roll angle, load factor, vertical airspeed and command airspeed, altitude, propulsion system, signal integrity or flight mode.

28. The method according to any one of claims 1 to 27, wherein the first group of one or more propellers comprises at least one propeller on any side of the fuselage of the aircraft.

29. The method according to any one of claims 1 to 28, wherein the first group of one or more propellers comprises all the tilting propellers of the aircraft.

30. A computer-readable medium storing an instruction set executable by at least one processor of a device to cause the device to perform the method according to any one of claims 1 to 29.

31. A flight control system for an aircraft, the flight control system comprising: The memory stores instructions; And a processor configured to execute the instructions to cause the flight control system to perform the method according to any one of claims 1 to 30.

32. A method for managing icing on an aircraft, the method comprising: Determine the icing status of the aircraft; And to perform propeller adjustment on one or more propellers based on the icing conditions, wherein performing the propeller adjustment includes: moving at least one propeller of a first group of one or more propellers from a first angular position to a second angular position, the at least one propeller including at least a first blade and a second blade; wherein: in the first angular position, a first surface of one of the first blades or the second blade faces away from the forward airflow, and a second surface of one of the first blades or the second blade faces the forward airflow, and in the second angular position, the second surface faces away from the forward airflow, and the first surface faces the forward airflow.

33. The method of claim 32, wherein the first surface includes the tip of the first blade, and the second surface includes the tip of the second blade.

34. The method of claim 32, wherein the first surface includes the leading edge of the first blade, and the second surface includes the trailing edge of the first blade.

35. The method of claim 32, wherein the first surface includes the leading edge of the first blade, and the second surface includes the leading edge of the second blade.

36. The method of claim 32, wherein the first surface includes the trailing edge of the first blade, and the second surface includes the trailing edge of the second blade.

37. The method according to any one of claims 32 to 37, wherein the at least one propeller comprises a tilting propeller.

38. The method according to any one of claims 32 to 37, wherein the at least one propeller comprises a lift propeller.

39. A computer-readable medium storing an instruction set executable by at least one processor of a device to cause the device to perform the method according to any one of claims 32 to 38.

40. A flight control system, the flight control system comprising: The memory stores instructions; And a processor configured to execute the instructions to cause the flight control system to perform the method according to any one of claims 32 to 39.

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