Systems and methods for aircraft cooling using phase change materials

Abstract

An aircraft engine cooling system may comprise phase change materials (PCM) configured to provide auxiliary, temporary or emergency cooling. In some embodiments, a PCM jacket (206) may surround portions of a heat exchanger (204) to provide additional cooling capacity during high-heat phases of flight in a vertical takeoff and landing aircraft. In some embodiments, an auxiliary PCM-based heat exchanger may be selectively connected to a coolant circuit. In some embodiments, a PCM material may be embedded within voids of an electric engine, such as within a cavity between a motor and inverter.

Description

Agent Ref. No. 16498-0015-00304SYSTEMS AND METHODS FOR AIRCRAFT COOLING USING PHASE CHANGE MATERIALSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present disclosure claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 697,865, filed September 23, 2024, entitled “SYSTEMS AND METHODS FOR AIRCRAFT COOLING USING PHASE CHANGE MATERIALS,” the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] This disclosure relates generally to the field of powered aerial vehicles. More particularly, and without limitation, the present disclosure relates to innovations in aircraft that use electrical propulsion systems. Certain aspects of the present disclosure generally relate to configuring phase change materials (PCM) for cooling components of an aircraft. Other aspects of the present disclosure generally relate to improvements in configuring phase change materials for cooling components that may be used in other types of vehicles but provide particular advantages in aerial vehicles.BACKGROUND

[0003] Vertical takeoff and landing (VTOL) aircraft, such as helicopters and electric aircraft, typically include one or more propellers configured to propel air downward to provide vertical lift for takeoff, landing and hovering. The propellers may be driven by engines that generate large amounts of heat during these phases of flight.SUMMARY

[0004] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller of the aircraft; an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine, the heat exchanger comprising an air inlet and an air outlet; and a first container storing a phase change material, the first container being thermally coupled to the heat exchanger, wherein the first container is thermally coupled to the heat exchanger.

[0005] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller of the aircraft; an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine; a container storing a phase change material; and a pipe system thermally coupled to the engine, the heat exchanger, and the container, wherein the pipe system is configured to deliver a cooling fluid from the engine, to the heat exchanger, to the container, and back to the engine.Agent Ref. No. 16498-0015-00304

[0006] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an end bell located at an end of the motor, the end bell comprising a chamber containing a phase change material.

[0007] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an end bell located at an end of the motor and thermally coupled to a thermal plate between the end bell and the motor, wherein the thermal plate comprises a phase change material.

[0008] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an engine oil sump thermally coupled to an insert comprising a phase change material.

[0009] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a housing surrounding the motor, the housing comprising a container comprising a phase change material; and a heat exchanger thermally coupled to the engine, wherein the propeller system is configured to enable a cooling fluid to circulate between the heat exchanger, the engine, and the housing, and wherein the container is positioned to be in direct contact with a cooling fluid.

[0010] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a phase change material; and an inverter electrically coupled to the motor, the inverter comprising an inverter capacitor, wherein the inverter capacitor has a surface adjacent the phase change material.

[0011] In some embodiments, this disclosure provides for a propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; a phase change material; and an inverter electrically coupled to the motor, the inverter comprising: anAgent Ref. No. 16498-0015-00304 inverter capacitor, and an inverter capacitor housing for the inverter capacitor, wherein the inverter capacitor housing and the phase change material are thermally coupled.

[0012] In some embodiments, this disclosure provides for a method for operating an aircraft, the aircraft comprising any of the propeller systems described in this disclosure, the method comprising operating the engine during takeoff or landing of the aircraft.

[0013] In some embodiments, this disclosure provides for a computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform any of the methods for operating an aircraft described in this disclosure.

[0014] Embodiments of the present disclosure may provide a propeller system for an aircraft, including a drive shaft configured to drive a propeller of the aircraft. An engine may be configured to rotate the drive shaft. A heat exchanger may be thermally coupled to the engine. The heat exchanger may include an air inlet, an air outlet, and a first side surface between the air inlet and the air outlet. A first container may store a phase change material. The first container may be thermally coupled to the heat exchanger. The first container may be mechanically coupled to the first side surface.

[0015] Embodiments of the present disclosure may provide a propeller system for an aircraft, including a drive shaft configured to drive a propeller of the aircraft. An engine may be configured to rotate the drive shaft. A heat exchanger may be thermally coupled to the engine. A container may store phase change material. A pipe may be thermally coupled to the engine, the heat exchanger, and the container. The pipe may be configured to deliver cooling fluid from the engine, to the heat exchanger, to the container, and back to the engine.

[0016] Embodiments of the present disclosure may provide a propeller system including a drive shaft configured to drive a propeller in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. A housing may surround the motor. The housing may include an end bell located at an end of the motor. The end bell may include a chamber containing a phase change material.

[0017] Embodiments of the present disclosure may provide a propeller system for an aircraft, including a drive shaft configured to drive a propeller in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. A housing may surround the motor. The housing may include an end bell located at an end of the motor and mechanically coupled to a thermal plate between the end bell and the motor. The thermal plate may include a phase change material.Agent Ref. No. 16498-0015-00304

[0018] Embodiments of the present disclosure may provide a propeller system for an aircraft, including a drive shaft configured to drive a propeller in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. A housing may surround the motor. The housing may include an engine oil sump. The engine oil sump may be mechanically coupled to an insert comprising a phase change material.

[0019] Embodiments of the present disclosure may provide a propeller system for an aircraft, including a drive shaft configured to drive a propeller in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. A housing may surround the motor. The housing may include a phase change material. The phase change material may be configured to be in direct contact with oil.

[0020] Embodiments of the present disclosure may provide a propeller system for an aircraft, including a drive shaft configured to drive a propeller in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. An inverter may be electrically coupled to the motor. The inverter may include an inverter capacitor. The inverter capacitor may be covered on a surface by a phase change material.

[0021] Embodiments of the present disclosure may provide a propeller system for an aircraft, including a drive shaft configured to drive a propeller in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. An inverter may be electrically coupled to the motor. The inverter may include an inverter capacitor and a housing for the inverter capacitor. The housing may comprise a phase change material.BRIEF DESCRIPTIONS OF FIGURE AND APPENDIX IMAGES

[0022] Figure 1A illustrates an example VTOL aircraft in a cruise configuration, consistent with embodiments of the present disclosure.

[0023] Figure IB illustrates an example VTOL aircraft in a lift configuration, consistent with embodiments of the present disclosure.

[0024] Figure 2 illustrates an example boom housing an engine and a heat exchanger with phase change material, consistent with embodiments of the present disclosure.

[0025] Figure 3 illustrates an example of a flow of oil through a passage with phase change material for cooling an engine, consistent with embodiments of the present disclosure.

[0026] Figure 4 illustrates an example of an end bell of a motor housing with phase change material, consistent with embodiments of the present disclosure.

[0027] Figure 5 illustrates an example of an end bell of a motor with phase change material, consistent with embodiments of the present disclosure.Agent Ref. No. 16498-0015-00304

[0028] Figure 6 illustrates an example of an engine oil sump with insert including phase change material, consistent with embodiments of the present disclosure.

[0029] Figure 7 illustrates an example of an engine housing with phase change materials, consistent with embodiments of the present disclosure.

[0030] Figure 8A illustrates an example of an inverter capacitor with phase change materials, consistent with embodiments of the present disclosure.

[0031] Figure 8B illustrates an example of an inverter capacitor housing with phase change material, consistent with embodiments of the present disclosure.

[0032] Figure 8C illustrates an example of a stack of inverter capacitors with intervening phase change material, consistent with embodiments of the present disclosure.

[0033] Figures 9A and 9B are graphical depictions of a reduction in temperature of components of a propeller system using phase change material, consistent with embodiments of the present disclosure.DETAILED DESCRIPTION

[0034] The present disclosure addresses components of cooling system in aircraft, such as vertical takeoff and landing (VTOL) aircraft. For example, the present disclosure is directed to auxiliary cooling systems for optimizing the cooling capacity of VTOL aircraft in high heat, short duration scenarios. Such scenarios may comprise certain phases of flight in which propeller engines generate more heat than in other phases of flight, such as during takeoff, landing and hovering. For example, some propellers may be used almost exclusively in these phases of flight. Alternatively, a short-distance flight itself may constitute a short duration scenario in which high heat loads are generated. Additionally, a VTOL aircraft may encounter unexpected situations that result in higher than anticipated levels of heat generation. Such situations may include, e.g., a cooling system failure or other overheating emergency, or an in-flight delay such as an unscheduled holding pattern in a high-traffic airspace.

[0035] VTOL aircraft may be designed with cooling systems to remove heat from an engine. For example, the cooling systems may be configured to direct a cooling airflow through heat transfer elements coupled to the engines, such as cooling fins or an air-oil heat exchanger. However, sizing such cooling systems to handle the above-described short-duration scenarios may incur a high penalty in cost, size, weight, and energy. Accordingly, it may be desirable to configure a cooling system with auxiliary components that can provide extra cooling capacity when needed.Agent Ref. No. 16498-0015-00304

[0036] Embodiments of the present disclosure provide cooling system designs in which phase change materials are arranged to provide additional cooling capacity for routine or emergency scenarios in which high heat loads are temporarily generated. In some embodiments, a PCM jacket may surround portions of a heat exchanger to provide additional cooling capacity during high-heat phases of flight. In some embodiments, an auxiliary PCM- based heat exchanger may be selectively connected to a coolant circuit. In some embodiments, a PCM material may be embedded within voids of an electric engine, such as within a cavity between a motor and inverter. In some embodiments, any combination of the implementations of PCM described herein may be used together within a single system.

[0037] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise represented. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the disclosure. Instead, they are merely examples of apparatuses and methods consistent with aspects related to the subject matter recited in the appended claims.

[0038] Figs. 1A-B illustrate a VTOL aircraft 100 in a cruise configuration and a vertical take-off, landing and hover configuration (also referred to herein as a “lift” configuration), respectively, consistent with embodiments of the present disclosure. Aircraft 100 may include a fuselage 102, wings 104 mounted to fuselage 102, tail 105, and one or more rear stabilizers 106 mounted to tail 105 or the rear of fuselage 102. A plurality of lift propellers 112 may be mounted to wings 104 and configured to provide lift for vertical take-off, landing and hover. A plurality of tilt propellers 114 may be mounted to wings 104 and may be tiltable between the cruise configuration in which they provide forward thrust to aircraft 100 for horizontal flight, as shown in Fig. 1A, and the lift configuration in which they provide a portion of the lift required for vertical take-off, landing and hovering, as shown in Fig. IB. As used herein, a lift configuration may refer to a tilt propeller orientation in which the tilt propeller thrust is providing primarily lift to the aircraft. A cruise configuration may refer to a tilt propeller orientation in which the tilt propeller thrust is providing primarily forward thrust to the aircraft. Alternatively, a cruise configuration may refer to a configuration in which a lift propeller is stowed.

[0039] In some embodiments, lift propellers 112 may be configured for providing lift only, with all propulsion being provided by the tilt propellers. Accordingly, lift propellers 112 may be in fixed positions and may only generate thrust during take-off, landing and hover.Agent Ref. No. 16498-0015-00304Meanwhile, tilt propellers 114 may be tilted to lift configurations in which their thrust is directed vertically for providing additional lift.

[0040] For forward flight, tilt propellers 114 may tilt from their lift configurations to their cruise configurations. In other words, the pitch and tilt angle of tilt propellers 114 may be varied from an orientation in which the tilt propeller thrust is directed vertically (to provide lift during vertical take-off, landing and hover) to an orientation in which the tilt propeller thrust is directed horizontally (to provide forward thrust to aircraft 100). The tilt propellers may tilt about axes that may be perpendicular to the forward direction of aircraft 100. When aircraft 100 is in full forward flight during the cruise configuration, lift may be provided entirely by wings 104. Meanwhile, lift propellers 112 may be shut off. The blades 120 of lift propellers 112 may be locked in low-drag positions for aircraft cruising. In some embodiments, lift propellers 112 may each have two blades 120 that may be locked for cruising in minimum drag positions in which one blade is directly in front of the other blade as illustrated in Fig. 1A. In some embodiments, lift propellers 112 have more than two blades. In some embodiments, tilt propellers 114 include more blades 118 than lift propellers 112. For example, as illustrated in Figs. 1A-B, lift propellers 112 may each include, e.g., two blades and tilt propellers 114 may each include, e.g., five blades. In some embodiments, tilt propellers 114 may have, e.g., from 2 to 5 blades.

[0041] In some embodiments, the aircraft may include only one wing 104 on each side of fuselage 102 (or a single wing that extends across the entire aircraft) and at least a portion of lift propellers 112 may be located rearward of wings 104 and at least a portion of tilt propellers 114 may be located forward of wings 104. In some embodiments, all of lift propellers 112 may be located rearward of wings 104 and all of tilt propellers 114 may be located forward of wings 104. According to some embodiments, all lift propellers 112 and tilt propellers 114 may be mounted to the wings — i.e., no lift propellers or tilt propellers may be mounted to the fuselage. In some embodiments, lift propellers 112 may be all located rearwardly of wings 104 and tilt propellers 114 may be all located forward of wings 104. According to some embodiments, all lift propellers 112 and tilt propellers 114 may be positioned inwardly of the wing tips 109.

[0042] In some embodiments, lift propellers 112 and tilt propellers 114 may be mounted to wings 104 by booms 122. Booms 122 may be mounted beneath wings 104, on top of the wings, and / or may be integrated into the wing profile. In some embodiments, one lift propeller 112 and one tilt propeller 114 may be mounted to each boom 122. Lift propeller 112 may be mounted at a rear end of boom 122 and tilt propeller 114 may be mounted at aAgent Ref. No. 16498-0015-00304 front end of boom 122. In some embodiments, lift propeller 112 may be mounted in a fixed position on boom 122. In some embodiments, tilt propeller 114 may mounted to a front end of boom 122 via a hinge. Tilt propeller 114 may be mounted to boom 122 such that tilt propeller 114 is aligned with the body of boom 122 when in the cruise configuration, forming a continuous extension of the front end of boom 122 that minimizes drag for forward flight.

[0043] In some embodiments, aircraft 100 may include, e.g., one wing on each side of fuselage 102 or a single wing that extends across the aircraft. According to some embodiments, the at least one wing 104 is a high wing mounted to an upper side of fuselage 102. According to some embodiments, the wings include control surfaces, such as flaps, ailerons or flaperons. According to some embodiments, the wings may have curved wing tips 109 for reduced drag during forward flight.

[0044] In some embodiments, rear stabilizers 106 include control surfaces, such as one or more rudders, one or more elevators, and / or one or more combined rudder-elevators. The wing(s) may have any suitable design. For example, the wings have a tapering leading edge or a tapering trailing edge. In some embodiments, the wings may have a substantially straight leading edge in the central section of wings 104.

[0045] Aircraft 100 may include at least one door 110 for passenger entry and exit. In some embodiments, door 110 may be located beneath and forward of wings 104 as seen in Figs. 1A-B.

[0046] Further discussion of VTOL aircraft may be found in U.S. Patent Publication No. 2021 / 0362849, which is incorporated by reference in its entirety for all purposes.

[0047] As discussed above, operation of a motor or engine produces substantial heat that may be dissipated to protect the various electrical and mechanical components. With respect to a VTOL, the engine or motor driving lift propeller 112 or tilt propeller 114 through a drive shaft may benefit from additional cooling components in contact with the heat exchanger, engine, inverter, or oil. For example, during take-off or landing phases, a substantial generation of heat occurs, which may present issues with longevity, safety, and efficiency of these components. Additional cooling materials added to various components of an aircraft propeller system may provide the means to prevent and / or reduce overheating of components. Further, such materials would provide a backup cooling system in the event that a primary cooling system fails or is not performing sufficiently. For example, a primary cooling system may comprise an air-oil heat exchanger that relies on airflow for cooling. But during take-off, landing, or hovering, airflow may be reduced through the heat exchanger, so a backup cooling system would be beneficial. Other short duration, high heat scenarios may benefitAgent Ref. No. 16498-0015-00304 from a backup or auxiliary system such as, e.g., short flights, in-air delays, cooling system failures, etc. Such a cooling system may include the use of phase change materials (PCM) in various components of a propeller system.

[0048] PCM may be materials that absorb and release thermal energy during phase changes. PCM may include paraffin, fatty acid(s), alcohols, esters, salt hydrates, metals and / or alloys, (e.g., gallium, bismuth-tin), metal alloys, etc. PCM may be used to regulate the temperature of a system or component by storing and releasing heat. Different PCM may have different latent heat properties in relation to their thermodynamic behavior. The latent heat may refer to the amount of energy per unit of mass that a PCM may absorb or release during a phase change without a corresponding change in temperature. Typically, a PCM will have little effect until a predetermined threshold temperature is reached, above which a phase change begins to occur in the PCM such as, e.g., a transition from a solid to a liquid state. Once the PCM has completed the phase change, the temperature will continue to increase again. During cooler periods, the PCM may revert to its prior state (such as solid) as it releases the absorbed heat, leaving the PCM ready for use again in a subsequent high heat load scenario. Therefore, by using a PCM with a targeted predetermined phase change temperature threshold, a cooling system would have a cooling mechanism configured to temporarily delay subsequent rises in temperature above unsafe or undesirable levels.

[0049] In some embodiments, the selection of PCM may be based on a latent heat (e.g., the thermal energy absorbed or released by a substance during a phase transition and / or the heat storage capacity), phase change temperature, thermal conductivity, and / or compatibility with engine fluids (e.g., engine cooling oil). A plurality of PCM types may be used in combination, each PCM selected to activate at different temperature thresholds, thereby providing staged or multi-tiered cooling as operational demands increase. For example, a first PCM may activate during routine high-heat phases, while a second PCM with a higher threshold may provide emergency cooling during system failures or extreme scenarios. The PCM may be non-toxic and environmentally recyclable for sustainability.

[0050] The predetermined threshold may be chosen to target a safe operating maximum temperature for one or more components of an engine. For example, a PCM with a predetermined threshold similar to the safe operating maximum temperature may be chosen so that the PCM may be activated if, e.g., a primary cooling system fails. Alternatively, a cooling system may be sized such that its cooling capacity cannot keep up with a heat load beyond a predetermined time duration, such as an expected flight time. In such a case, the PCM may be configured to provide additional cooling capacity when an actual flight timeAgent Ref. No. 16498-0015-00304 exceeds the expected flight time. Furthermore, a PCM may be used to provide additional cooling capacity in expected high heat loads such as during vertical flight. In some embodiments, a combination of a plurality of PCMs with different predetermined thresholds may be used. Thus, the implementations of PCM in the propeller systems as described herein may provide a backup or emergency cooling mechanism to protect various system components or increase their longevity or efficiency.

[0051] In some embodiments, operational data (e.g., measurement data from various system sensors on the VTOL aircraft of FIGS. 1 A-1B) may be logged by the system and analyzed to inform subsequent selection and spatial placement of PCM. Such data may include thermal profiles (e.g., temperature of cooling fluid), heat flux through system components, and / or environmental conditions encountered during flight operations. The implementation of PCM- based thermal management systems may reduce the overall aircraft weight and energy consumption relative to conventional oversized cooling systems, thereby enhancing operational efficiency, thermal reliability, and environmental sustainability.

[0052] Further details of PCM implementations in VTOL engines and / or propeller systems (e.g., as described with respect to Figs. 1A-1B) are described below with respect to Figs. 2- 9B. Disclosed embodiments may be implemented and / or incorporated in a boom of an aircraft including an engine (e.g., an electric motor) configured to drive a drive shaft and thereby rotate a propeller to operate an aircraft in various flight conditions (e.g., lift configuration and / or cruise configuration).

[0053] Fig. 2 illustrates an example engine 202 and heat exchanger 204 with PCM 206, consistent with embodiments of the present disclosure. Engine 202 may comprise part of, e.g., a lift or tilt propeller system (such as e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) In some embodiments, engine 202 may be housed in a boom 222. Engine 202 may be configured to cause a drive shaft to rotate a propeller of an aircraft. For example, engine 202 may comprise an electric engine including components such as a motor, a gearbox, and an inverter. These components may be cooled heat transfer with a circulating oil flow path inside engine 202. The heated oil may be cooled by circulation through an air-oil heat exchanger 204, which may be thermally coupled to engine 202 by, e.g., a coolant circuit such as an oil flow path. In some embodiments, heat exchanger 204 may be mechanically coupled to engine 202. In some embodiments, heat exchanger 204 may comprise a primary cooling system for engine 202. In some embodiments, an oil circulation path may not be present and heat exchanger 204 may comprise another heat type of heat transfer element such as, e.g. cooling fins.Agent Ref. No. 16498-0015-00304

[0054] Heat exchanger 204 may include an inlet side and an outlet side for receiving and discharging airflow. Any other side or surface of heat exchanger 204 may be in contact with PCM 206 or a first container housing PCM 206. For example, PCM 206 may comprise a jacket surrounding heat exchanger 204 while allowing air to flow through the inlet and outlet sides. This configuration of PCM 206 would allow for PCM 206 to act as a backup cooling system for heat exchanger 204. For example, PCM 206 may be configured to absorb high heat loads generated during takeoff, landing and hover, and subsequently dissipate the absorbed heat during periods of higher cooling capacity such as high speed, wing-borne cruise flight.

[0055] Disclosed systems and methods may include a propeller system for an aircraft. A drive shaft may be configured to drive a propeller of the aircraft. An engine (e.g., engine 202) may be configured to rotate the drive shaft. A heat exchanger (e.g., heat exchanger 204) may be thermally coupled to the engine. The heat exchanger may include an air inlet, an air outlet, and a side surface between the air inlet and the air outlet. A container may store a phase change material (e.g., PCM 206). The container may be thermally and / or mechanically coupled to the heat exchanger, for example, to facilitate heat exchange. The container may be thermally and / or mechanically coupled to the side surface. The side surface may be any side of the heat exchanger where the primary function of heat exchange with a passing fluid is not impeded. For example, the side surface may be a side of the heat exchanger where the heat exchanger does not interface with the engine, and / or where the fluid (e.g., air) inlet or fluid outlet are not located. The container may be any storage vessel capable of housing a phase change material. In some embodiments, the container may be part of the boom housing of an aircraft or part of a housing for the heat exchanger. The container may be formed of a lightweight, high thermal conductivity material, which may be rigid or flexible, and may be designed for modularity and rapid replacement or replenishment during maintenance. In some embodiments, the container may be removable, for example, for maintenance and / or replacement. For example, the container may be configured to be attachable to the heat exchanger or other component in the propeller system using clips or other forms of removable and / or reusable attachments, fasteners, or couplings. For example, the container may be formed of metals such as steel or aluminum, or may be formed of high thermal conductivity ceramics such as, e.g., aluminum nitride (AIN) or silicon carbide (SiC). In some embodiments, the container may comprise a pouch or other non-rigid construction.

[0056] In some embodiments, at least a portion of an air flow path from an air inlet of heat exchanger 204 to the air outlet of heat exchanger 204 runs parallel to a first side surface. InAgent Ref. No. 16498-0015-00304 this configuration, air flowing through heat exchanger 204 would experience thermal contact with PCM 206 along a full flow path from the inlet to outlet sides of heat exchanger 204, providing more surface area for heat energy transfer and improved thermal management. This arrangement may be optimized to maximize the efficiency of heat absorption by PCM 206 during high-heat phases (e.g., lift configuration) and facilitate dissipation of heat during periods of lower thermal demand (e.g., cruise configuration).

[0057] In some embodiments, a second side surface of heat exchanger 204 may be located between the air inlet surface and the air outlet surface. Consistent with some embodiments, the container with PCM 206 may be mechanically coupled to the second side surface.Therefore, at least two side surfaces of heat exchanger 204 may provide thermal contact with PCM 206 or a first container storing PCM 206. In some embodiments, the container may wrap around heat exchanger 204 (e.g., if heat exchanger 204 has a curved side surface). The first container may be formed of a lightweight, high thermal conductivity material, which may be, e.g., rigid or flexible. Consistent with some embodiments, the first container may include a first sub-container mechanically coupled to the first side surface and a second subcontainer mechanically coupled to the second side surface. In some embodiments, PCM 206 may include layers of PCM or different types of PCM. The different types of PCM may be commonly stored or split into sub-containers, enabling staged or multi-tiered cooling as operational demands increase. Consistent with some embodiments, a second container may store the phase change material. The container may be mechanically coupled to the second side surface. The second container may be separate from the first container. This modular approach allows for tailored thermal management and simplified maintenance.

[0058] In some embodiments, PCM 206 may change phase at a predetermined threshold temperature (e.g., a phase change temperature) higher than an operating temperature of the heat exchanger (e.g., heat exchanger 204). As used herein, operating temperature may refer to a temperature or range of temperatures determined to be acceptable for safe and / or effective operational use of any device or component of the propeller system (e.g., a heat exchanger or engine component). For example, above such a temperature, components in heat exchanger 204 may begin to fail, or heat exchanger 204 may not be able to release heat efficiently into the air stream. Alternatively or additionally, a threshold temperature determined for the heat exchanger may correspond to a threshold temperature of one or more components being cooled by the heat exchanger. Therefore in some embodiments, the predetermined threshold temperature may be based on a maximum allowable temperature of, e.g., one or more components of a propeller engine. More specifically, the predetermined thresholdAgent Ref. No. 16498-0015-00304 temperature may correspond to a temperature expected to be present at the heat exchanger surface when the one or more components reach the maximum allowable temperature. In some embodiments, the predetermined threshold temperature may be lower than a failure temperature of the heat exchanger or the one or more components being cooled by the heat exchanger. A failure temperature may correspond to a temperature at which the heat exchanger or other components become damaged or unsafe. It is desirable that the PCM undergoes a phase change below the failure temperature so that the heat absorption of the PCM becomes effective before the components become damaged. Therefore, in some embodiments, the predetermined threshold temperature at which phase change occurs may be bounded on a lower side by the normal operating temperature of the components and at an upper side by the failure temperature of such components.

[0059] In some embodiments PCM 206 may include a plurality of different phase change materials, each having (or characterized by) a different phase change temperature. For example, PCM of various predetermined threshold temperatures (e.g., phase change temperatures) may be used to control temperature changes for different system components, or to provide a multi-tiered backup cooling system. Each of these different PCM may be one or more of the PCM as described herein. For example, a mix of different PCMs may be configured in combination to fine-tune a desired threshold temperature, which may be based on a thermal property of a system component (e.g., a safety temperature of an engine component). This arrangement may enable staged activation of cooling functions, for example, with lower-threshold PCMs providing routine thermal management and higher- threshold PCMs delivering emergency cooling during system failures or extreme scenarios. In some embodiments, a phase change temperature of the PCM may be an average temperature of the different phase change temperatures of the different PCMs.

[0060] In some embodiments, heat exchanger 204 may include an end tank, with a container positioned either adjacent to or integrated with the end tank to facilitate heat exchange between the end tank and PCM 206. An end tank may refer to a chamber located at either end of heat exchanger 204 that collects and distributes cooling fluid, facilitating its flow through the exchanger's internal passages for efficient thermal transfer. This configuration may enable more efficient and / or controlled thermal interaction between heat exchanger 204 and PCM 206 housed within a container.

[0061] Fig. 3 illustrates an example of a flow of oil (depicted by arrows) through a passage with PCM 302 for cooling engine 202, consistent with embodiments of the present disclosure. Engine 202 may transfer heat to oil, coolant, or other type of cooling fluid duringAgent Ref. No. 16498-0015-00304 operation of a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B). Cooling fluid (e.g., oil) may flow through pipes (e.g., a pipe system) or passageways (e.g., in various paths) from engine 202 to heat exchanger 204 through heat exchanger inlet 304 to PCM 302 or a container (or passage) surrounded by PCM 302 through heat exchanger outlet 306. For example, the passage may be a pipe or tube with PCM 302 jacketing the pipe. In another example, PCM 302 may sandwich a passage or container on opposite sides. In some embodiments, the PCM container storing PCM 302 may be encapsulated by a rigid or flexible shell, epoxy, or other suitable encapsulating material to enhance thermal conductivity, mechanical protection, and containment of the PCM during phase transitions. PCM 302 may be selected such that a predetermined threshold temperature protects engine components from overheating. For example, if heat exchanger 204 is unable to keep up with cooling demands for engine 202, PCM 302 may act to protect engine 202 during operation with heavy cooling needs, including take-off or landing phases of a VTOL aircraft. As such, in some embodiments PCM 302 may have little cooling effect during operational periods below the predetermined phase change temperature, but may provide rapid heat absorption when the threshold is exceeded, thereby delaying further temperature rise and protecting sensitive components.

[0062] Disclosed systems and methods may include a propeller system for an aircraft. A drive shaft may be configured to drive a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) of the aircraft. An engine may be configured to rotate the drive shaft. A heat exchanger may be thermally coupled to the engine. A container 303 may store PCM 302. A pipe may be thermally coupled to the engine, the heat exchanger, and the container. The pipe may be configured to deliver the cooling fluid from engine 202, to heat exchanger 204, to container 303, and back to engine 202. As used herein, container 303 may be part of the boom housing, such as a chamber, or a storage vessel separate from the housing. Cooling fluid may be any fluid capable of flowing through pipes or passages to exchange and transfer heat (e.g., oil).

[0063] In some embodiments, heat exchanger 204 may be mechanically coupled to a housing of engine 202. For example, as shown in Fig. 2, heat exchanger 204 may be mounted, affixed, or otherwise mechanically coupled to a part of the housing for engine 202. PCM 302 may be located at any distance from heat exchanger 204, and connected by a pipe through which cooling fluid flows. For example, PCM 302 may be adjacent to heat exchanger 204, or PCM 302 may be located at a different location in the aircraft. In some embodiments, PCM may be located on a downstream (cool) side of heat exchanger 204 in a flow path direction.Agent Ref. No. 16498-0015-00304This may help ensure that a primary cooling function is performed by heat exchanger 204, and PCM 302 may be activated only when needed.

[0064] Returning to Fig. 3, the pipe may be thermally coupled to engine 202, heat exchanger 204, and container 303. The pipe may be configured to deliver the cooling fluid from the engine 202, to heat exchanger 204, to container 303, and back to engine 202. As used herein, container 303 may be part of the boom housing, such as a chamber, or a storage vessel separate from the housing. Cooling fluid may be any fluid capable of flowing through pipes or passages to exchange and transfer heat (e.g., oil). In some embodiments, the system may include temperature sensors and controllers configured to monitor the thermal state of the coolant and PCM 302, and to activate auxiliary cooling circuits or bypass valves (i.e., diverting valves, such as bypass valve 308) as needed for optimal thermal management. Bypass valve 308 may be configured to operate in a first state to direct the cooling fluid through heat exchanger 204 and / or container 303, and in a second state to direct the cooling fluid through bypass pipe 310 to bypass heat exchanger 204 and / or container 303. For example, the system may actuate bypass valve 308 when the temperature of the cooling fluid is at or below the predetermined threshold to direct the cooling fluid around container 303 (e.g., through a pipe 310 that bypasses container 303). For example, the system may actuate bypass valve 308 when the temperature of the cooling fluid exceeds the predetermined threshold to direct the cooling fluid to container 303 for cooling relief of heat exchanger 204 and / or container 303.

[0065] In some embodiments, the pipe system may include a plurality of first inlet pipes and a plurality of first outlet pipes (not shown) configured to deliver the cooling fluid from the plurality of first inlet pipes to heat exchanger 204 to the plurality of first outlet pipes. For example, heat exchanger 204 may receive heated cooling fluid from a plurality of first inlet pipes from different parts of engine 202 or power source (e.g., battery), and once the cooling fluid passes through heat exchanger 204, the cooling fluid passes through the plurality of first outlet pipes to a container 303 with PCM 302. In some embodiments, the plurality of first outlet pipes may be replaced by one larger pipe. For example, the cooling fluid may be merged from a plurality of first inlet pipes to one outlet pipe. This configuration may improve or optimize heat transfer efficiency and allow for redundancy in the cooling circuit.

[0066] In some embodiments, the pipe may include a plurality of second inlet pipes and a plurality of second outlet pipes configured to deliver the cooling fluid from the plurality of second inlet pipes to container 303 to the plurality of second outlet pipes. For example, PCM 302 may be in a container 303 with multiple passages or pipes directing flow of cooling fluid.Agent Ref. No. 16498-0015-00304Having a plurality of passages or pipes may allow for a greater exchange of heat between cooling fluid and PCM 302.

[0067] In some embodiments, the pipe may include a first bypass pipe having a first bypass valve configured to bypass heat exchanger 204. For example, a first bypass valve may be located at the inlet side of heat exchanger 204 and, when activated, the first bypass valve may redirect cooling fluid to flow around heat exchanger 204. Such a configuration may be beneficial for failure prevention or in emergency situations. For example, if heat exchanger 204 begins to fail or a leak is detected, the first bypass valve may be activated, allowing PCM 302 to provide emergency relief at least temporarily. The system may be configured to automatically activate the bypass valve based on temperature sensor’s input to improve response to abnormal and / or high-temperature conditions.

[0068] In some embodiments, the pipe may include a second bypass pipe having a second bypass valve configured to bypass container 303. The second bypass valve may allow cooling fluid to flow around container 303 storing PCM 302. For example, if PCM 302 has reached its maximum heat capacity, and the cooling fluid temperature begins to rise, PCM 302 may be bypassed by activating the second bypass valve until the cooling fluid temperature lowers again. In this example, when engine 202 is producing less heat, and cooling fluid temperature drops sufficiently, the second bypass valve may be closed to allow cooling fluid to remove heat from PCM 302. In another example, PCM 302 cooling fluid temperature may be low and PCM 302 not needed, so the second bypass valve may be opened to bypass PCM 302 container 303.

[0069] In some embodiments, PCM 302 may be configured to change phase at a predetermined threshold temperature higher than an operating temperature of heat exchanger 204. For example, if temperature of heat exchanger 204 reaches this threshold, then PCM 302 may begin to change phase, which will cease the temperature rise until PCM 302 has reached its capacity for heat retention. The predetermined threshold temperature may be based on any components of a propeller system. Such components may include the motor, engine, housing, inverter, etc. Various temperature sensors may be used to measure ambient of component temperatures.

[0070] In some embodiments, container 303 may include a plurality of separate sub-container 303s. For example, PCM 302 may include layers of PCM or different PCM split by subcontainer 303 s. Sub-container 303 s may be separate chambers of housing, with each containing a PCM with a different phase change temperature and / or latent heat. The subAgent Ref. No. 16498-0015-00304 container 303s may be placed near components where there is greater concern for overheating, enabling staged or multi-tiered cooling as operational demands increase.

[0071] In some embodiments, a cartridge filter may be operably coupled to one or more pipes of the pipe system such that cooling fluid flow through the cartridge filter that includes a PCM. The path of the cooling fluid, or cooling path, may refer to the route the cooling fluid takes as it circulates through the system to manage heat. For example, the cooling fluid may be pumped from a reservoir, flow through heat-generating components such as the engine or gearbox, and continue through various channels or conduits (e.g., in the propeller and / or engine housing) designed to absorb and dissipate heat. This path may be configured to pass through system components either in sequence or in parallel, depending on the thermal management needs of the system. This configuration may allow PCM 302 to absorb heat from the cooling fluid as it passes through the filter, providing both filtration and thermal management in a single component. Such an arrangement may be advantageous when one or two subsystems require dedicated cooling, enabling targeted protection of system components without the need for a more complex network.

[0072] For larger or more distributed systems, PCM 302 may be deployed in a networked configuration, with multiple PCM containers or cartridge filters positioned upstream, downstream, or in parallel to one another in the path of the cooling fluid. For example, a pair of PCM cartridges may be placed in parallel to improve overall heat exchange between the cooling fluid and PCM 302. This distributed approach allows for flexible thermal management, ensuring that heat absorption can be tailored to the specific needs of each subsystem. In some embodiments, the PCM containers may be arranged in parallel to maximize the cooling capacity, or selectively placed upstream to intercept heat before it reaches sensitive engine components. In some other embodiments, the PCM containers may be arranged in series, whereby the cooling fluid may flow from one to the next.

[0073] Fig. 4 illustrates an example of end bell 402 of a motor housing with PCM 404, consistent with embodiments of the present disclosure. As used herein, end bell 402 may comprise an end plate, cap, or piece of housing located at the end of a motor distal to the propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B). PCM 404 may be positioned in spaces within end bell 402 where otherwise air space, foam, and / or gaps may be present. For example, there may be cavities (e.g., compartments or pockets) in the housing of end bell 402 which, instead of foam, may be filled with PCM 404. By utilizing these otherwise unused spaces, the system may enhance thermal management without altering the core system design.Agent Ref. No. 16498-0015-00304

[0074] In some embodiments, end bell 402 may include separate chambers which house PCM 404. PCM 404 may be sealed in the chambers. For example, PCM 404 may allow heat exchange by conduction through walls of the chambers. In some embodiments, PCM 404 may be configured to release heat conductively through the end bell. The use of multiple chambers may facilitate the placement of different types or layers of PCM 404. PCM 404 may be configured to absorb heat from the motor during high-load operation and release heat conductively through the end bell to the surrounding environment or adjacent cooling systems. In some embodiments, PCM 404 may be encapsulated within a rigid or flexible shell, epoxy, or other suitable encapsulating material to enhance thermal conductivity, mechanical protection, and containment during phase transitions.

[0075] In some embodiments, PCM 404 may be separated from rotating components of the motor by a partition, such as a thermal plate. This arrangement may help ensure that PCM 404 acts as a thermal buffer, absorbing excess heat without interfering with the mechanical operation of the motor.

[0076] Disclosed systems and methods may include a propeller system for an aircraft. A drive shaft may be configured to drive a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. A housing may surround the motor. The housing may include an end bell located at an end of the motor. The end bell may include a chamber containing a PCM.

[0077] In some embodiments, end bell 402 may be thermally coupled to an inverter. For example, the inverter may be adjacent to end bell 402, allowing conduction of heat between the components. For example, in some embodiments PCM 404 may act as a thermal barrier between the moving parts of the motor (e.g. a rotor in a stator) and the inverter. Such a placement of PCM 404 may help prevent overheating of these components of a VTOL aircraft. By integrating PCM within the end bell to improve effective thermal coupling to the inverter, the system may maintain safe operating temperatures, enhance component longevity, and improve overall efficiency.

[0078] Fig. 5 illustrates an example of end bell 402 of a motor, consistent with embodiments of the present disclosure. Thermal plate 502 may be sandwiched between end bell 402 and the remainder of the motor housing. This configuration may allow thermal plate 502 to be in thermal contact with the inverter, end bell 402, and / or the motor, facilitating efficient heat transfer between the motor and inverter. On the right-hand side of Fig. 5 is a cut-out of thermal plate 502 and end bell 402 with diverting valve 504 (e.g., a diverting valve or bypassAgent Ref. No. 16498-0015-00304 valve). For example, diverting valve 504 may comprise an actively controllable (e.g., electronically actuated) diverting valve, or a passive element such as a thermostatic diverting valve. A thermostatic diverting valve may be configured to divert fluid automatically when the fluid passing through the valve reaches a predetermined temperature based on the thermostatic properties of the valve. Cooling fluid may flow through channels in the thermal plate 502 or end bell 402. For example, end bell 402 may comprise a PCM as shown in Fig. 4, and end bell 402 may comprise channels passing through or alongside the PCM. In some embodiments, thermal plate 502 may comprise a PCM. Diverting valve 504 may regulate flow through thermal plate 502 or end bell 402, depending on cooling fluid temperature or ambient temperature. Diverting valve 504 may be configured to direct the cooling fluid to the cooling fluid inlet when a temperature of the cooling fluid exceeds the predetermined temperature, and to direct the cooling fluid to the end bell when the temperature is lower than or equal to the predetermined temperature.

[0079] For example, during operation, cooling fluid may flow through thermal plate 502 to absorb heat from an inverter or other components of an engine. However, during a high heat load period (e.g., lift configuration or emergencies) in which a PCM may be activated, it may be desirable to place the PCM in greater thermal contact with the cooling fluid. Therefore diverting valve 504 may direct the cooling fluid to a secondary channel in closer thermal contact to a PCM, such as within end bell 402. When a temperature falls below thew predetermined temperature, cooling fluid may again be diverted to the thermal plate 502 by diverting valve 504.

[0080] Disclosed systems and methods may include a propeller system for an aircraft. An engine may be configured to rotate a drive shaft of a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B). The engine may include a motor. A housing may encase or surround the motor. The housing may include an end bell (e.g., end bell 402) located at an end of the motor and mechanically coupled to a thermal plate (e.g. thermal plate 502 of Fig. 5) between the end bell and the motor. The thermal plate may include a PCM.

[0081] In some embodiments, a heat exchanger may be thermally coupled to the engine. The engine may include a motor with end bell 402 containing a PCM and a thermal plate 502. Cooling fluid may flow through diverting valve 504 and thermal plate 502 or end bell 402 to the heat exchanger, where air flow may remove heat. For example, the heat may be exhausted from an air outlet in a VTOL or other aircraft. In some embodiments, the heat exchanger may be mechanically coupled to a housing of the engine. The heat exchanger may be coupled to a side of the engine, allowing for at least two means of heat exchange: conduction and flowAgent Ref. No. 16498-0015-00304 from cooling fluid (i.e., oil). This dual-path approach may enhance overall cooling efficiency and system redundancy.

[0082] In some embodiments, thermal plate 502 may include a plurality of separate subcontainers containing the phase change material. For example, along thermal plate 502, cooling fluid may pass through different sub-containers in a path that increases surface area contact of the PCM within thermal plate 502. This arrangement may enable staged or multitiered cooling, with each sub-container activating at different temperature thresholds to provide optimal thermal management across a range of operating conditions.

[0083] In some embodiments, a PCM in thermal plate 502 may be configured to change phase at a predetermined threshold temperature higher than an operating temperature of the heat exchanger, as described previously. In some embodiments, the thermal plate may include a plurality of different phase change materials. For example, different phase change materials may be selected depending on their different predetermined temperature thresholds. This may enable sequential activation of cooling functions, with lower-threshold PCMs providing routine thermal management and higher-threshold PCMs delivering emergency cooling during system failures or extreme scenarios.

[0084] With respect to Figs. 4-5, PCM may be placed adjacent to end bell 402 and engine interface. In some embodiments, a PCM embedded package can be positioned at this interface, designed as a cartridge filter element with dimensions tailored to fit within available pockets in the engine structure. The PCM cartridge may be installed at either the inlet or outlet side of the heat exchanger, depending on the desired thermal management strategy.

[0085] This modular PCM cartridge may be attached in place during periods of anticipated high thermal load. For example, extra cooling may be beneficial on hot days or during takeoff or landing. When additional cooling is not required, the opening can be capped off with a threaded plug, allowing for flexible operation and / or maintenance. The PCM cartridge may incorporate optional heat transfer enhancement features, such as fins or thermally conductive additives, to improve the rate and uniformity of heat absorption. For example fins in the PCM cartridge may direct the flow of cooling fluid and may be operated by a diverting valve (e.g., diverting valve 504).

[0086] The location, composition, or phase change temperature of the PCM cartridge within end bell 402 and / or the engine (e.g., engine 202 in Figs. 2-3) may be selected based on operational requirements. For example, PCM placed at the heat exchanger outlet (e.g., heat exchanger outlet 306 in Fig. 3) may have a phase change temperature that corresponds to anAgent Ref. No. 16498-0015-00304 average temperature of cooled fluid exiting the heat exchanger (e.g., 71 °C), while PCM placed at the inlet (e.g., heat exchanger inlet 304 in Fig. 3) may have a phase change temperature that corresponds to a higher average temperature of hot fluid entering the heat exchanger (e.g., 95°C). For example, the PCM may be configured to have a phase change temperature that is higher than the average temperatures by a predetermined threshold, such as, e.g., 2, degrees, 5 degrees, or 10 degrees. In some embodiments, two or more different PCMs may be placed at both the inlet and outlet sides of a heat exchanger. By strategically positioning the PCM cartridge, the system may improve the performance of thermal buffering and protect engine components from overheating during flight take-off or landing, or during emergencies.

[0087] In addition to heat exchanger arrangements, PCM may also be integrated into an engine oil sump to further enhance thermal management. Fig. 6 illustrates an example of engine oil sump 602 with insert 604 including phase change material, consistent with embodiments of the present disclosure. Engine oil sump 602 may be positioned at a lower portion of engine 202 to act as a sump for oil or other cooling fluid to recirculate through a cooling or lubrication system for engine 202. For example, engine 202 may produce hot oil during operation (e.g., take-off or landing of VTOL with lift propeller 112 or tilt propeller 114 of Figs. 1A-1B). Having an extra component to help soak and release heat would be beneficial to efficient operation of engine 202. Insert 604 including PCM may be placed in or around engine oil sump 602 (e.g., thermally coupled) to help absorb and redistribute heat from engine oil, particularly if a predetermined temperature threshold has been reached. Such a configuration may be beneficial when a predetermined temperature threshold is reached, providing a backup or auxiliary cooling function to protect sensitive engine components.

[0088] In some embodiments, insert 604 may be formed of a PCM. In some other embodiments, insert 604 may include a shell that houses a PCM. The shell may be constructed from a thermally conductive material to facilitate efficient heat transfer. In some embodiments, insert 604 may be a combination of shell and PCM. The PCM may be encapsulated within the shell using a rigid or flexible material, such as epoxy, to provide mechanical protection and containment during phase transitions. In some embodiments, insert 604 may include a plurality of different PCM, with each selected for specific phase change temperatures and / or latent heat, enabling staged or multi-tiered cooling as operational demands increase.

[0089] In some embodiments, the PCM used in insert 604 may exhibit relatively poor thermal conductivity in its molten state. This poor thermal conductivity may help to spreadAgent Ref. No. 16498-0015-00304 out the thermal energy within the PCM volume, maximizing the efficiency of heat absorption and retention. By slowing the rate at which heat is conducted away, the PCM can maintain a more uniform temperature profile and prolong the duration of effective cooling, especially during extended high-heat events. For example, PCMs with inherently poor thermal conductivity include organic PCMs, such as paraffin waxes and fatty acids, which are common in applications like building thermal management and cooling systems due to their high latent heat and stability. The low thermal conductivity (around 0.2-0.3 W nr' K-1) of these PCMs may slow down energy storage and release.

[0090] To further enhance thermal management, insert 604 may be constructed from layered materials, with each layer comprising a PCM selected for a specific phase change temperature or thermal property. This layered approach may improve cooling efficiency. For example, layered arrangement may behave as a PCM with a phase change temperature equal to an average of the phase change temperatures individual PCM’s, but it may take a longer time to change phase as compared to the individual PCMs on their own. In some embodiments, the PCM has a latent heat property, and the PCM is selected to maintain a predetermined operating temperature of a system component (e.g., a drive shaft, an engine, a heat exchanger, or any component therein). The predetermined operating temperature may refer to a temperature threshold above which the component experiences degradation, damage, or other unsafe characteristics. By selecting a PCM or a volume of PCM with an appropriate latent heat, the right balance can be struck between cost, weight, and efficiency in maintaining safe operating temperatures for engine and / or other aircraft components.

[0091] While insert 604 is illustrated with respect to a sump (e.g., oil sump), embodiments of the present disclosure are not limited to this configuration. In general, form-fitting PCM shells or components may be configured to fit into compact spaces of an engine, such as within a motor, gearbox, or inverter, where temporary high heat loads may cause damage. This arrangement may be beneficial in that it does not require the heat to be carried away by a coolant system and can instead absorb heat directly at its source to prevent component wear, damage, and / or failure. Some example locations are discussed with respect to Fig. 7 below.

[0092] Disclosed systems and methods may include a propeller system for an aircraft (e.g., a VTOL as disclosed). An engine (i.e., engine 202) may be configured to rotate a drive shaft. A drive shaft may be configured to drive a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) in the aircraft. The engine may include a motor. A housing may surround the motor. The housing may include an engine oil sump (e.g., engine oil sump 602). The engineAgent Ref. No. 16498-0015-00304 oil sump may be mechanically coupled to an insert (e.g., insert 604), which may include PCM. The insert may be configured to be in direct contact with oil.

[0093] Fig. 7 illustrates an example of engine 202 housing with PCM 702, consistent with embodiments of the present disclosure. Engine 202 may include flow channels or pipes for cooling fluid (i.e., oil) to flow. These flow channels may be located at various places in and around the housing of engine 202, such that cooling fluid may flow to the moving parts for lubrication and cooling. In some locations, PCM 702 may be placed in the housing to provide additional cooling function for when the cooling fluid reaches a predetermined temperature threshold. In some embodiments, PCM 702 is placed in spaces in the walls of the housing. In some embodiments, PCM 702 may be in direct contact with cooling fluid. PCM 702 may be positioned where otherwise air space, foam, and / or gaps are located in housing of engine 202. For example, there may be cavities in the housing of engine 202 which, instead of foam, may be filled with PCM 702. By utilizing these otherwise unused spaces, the system may enhance thermal management without altering the core system design. When cooling fluid circulates between a heat exchanger, the engine, and the housing, PCM 702 in the housing helps to cool heated cooling fluid.

[0094] In some embodiments, PCM 702 may be housed in a container (e.g., similar to the containers described with respect to Figs. 2-3). The container may be in direct contact with cooling fluid to facilitate heat exchange between the cooling fluid and PCM 702. For example, PCM 702 may be liquified when melted and the walls of the container may maintain a physical barrier to prevent PCM 702 from mixing with the cooling fluid.

[0095] Disclosed systems and methods may include a propeller system for an aircraft (e.g., a VTOL as disclosed). A drive shaft may be configured to drive a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) in the aircraft. An engine (e.g., engine 202) may be configured to rotate the drive shaft. The engine may include a motor. A housing may surround the motor. The housing may include a PCM (e.g., PCM 702 in Fig. 7). The PCM may be configured to be in direct contact with oil.

[0096] In some embodiments, PCM 702 may be in the housing of a stator of the motor. A stator may be the stationary component of a motor. The stator may receive power and causes rotation of a rotor of the motor. Rotation of the rotor and generation of energy to produce the rotation may produce heat. PCM 702 in the housing may help regulate this heat and prevent overheating. For example, PCM 702 may be located (e.g., in a container) in a compartment of the stator, rotor, inverter, or other motor and / or engine component. For example, PCM 702 may be housed in a container, and the container in direct contact with cooling fluid.Agent Ref. No. 16498-0015-00304

[0097] Fig. 8A illustrates an example of inverter capacitor component 800 with PCM 802, consistent with embodiments of the present disclosure. Inverter capacitor component 800 may include an inverter capacitor mounted within inverter by inverter capacitor housing 804. The inverter capacitor may comprise, e.g., a DC link capacitor for smoothing the DC current through the inverter. PCM 802 may be placed on the inverter capacitor as a thermal barrier to regulate temperature changes and prevent overheating of inverter capacitor component 800. In some embodiments, a cover may be used to hold PCM 802 in place, which may help ensure thermal contact and mechanical protection. The inverter capacitor may have a surface or a side adjacent and / or facing PCM 802. PCM 802 may be selected for its phase change temperature and / or latent heat to match the operational requirements of the inverter, and may be encapsulated in a rigid or flexible shell, or integrated with other materials such as epoxy for enhanced durability and containment.

[0098] Disclosed systems and methods may include a propeller system for an aircraft (e.g., a VTOL as disclosed). A drive shaft may be configured to drive a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. An inverter may be electrically coupled to the motor. The inverter may include an inverter capacitor. The inverter capacitor may be covered on a surface by a PCM (e.g., PCM 802 in Fig. 8A).

[0099] Fig. 8B illustrates an example of inverter capacitor housing 804 with PCM 852 (for inverter capacitor component 850), consistent with embodiments of the present disclosure. Inverter capacitor housing 804 may be used to mount an inverter capacitor. The inverter capacitor may have a surface or a side adjacent to and / or facing PCM 852. PCM 852 may be used as a jacket to surround inverter capacitor housing 804 on at least one side and thermally couple the PCM to the inverter capacitor housing. By surrounding the inverter capacitor, PCM 852 may help regulate heat and prevent overheating of inverter capacitor component 850. In some embodiments, this PCM jacket may be modular or replaceable, allowing for customization of PCM materials to suit specific operational requirements or environmental conditions.

[0100] Disclosed systems and methods may include a propeller system for an aircraft (e.g., a VTOL as disclosed). A drive shaft may be configured to drive a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. An inverter may be electrically coupled to the motor. The inverter may include an inverter capacitor, and a housing for theAgent Ref. No. 16498-0015-00304 inverter capacitor (e.g., inverter capacitor housing 804 in Fig. 8B). The housing may comprise a PCM (e.g., PCM 852 in Fig. 8B).

[0101] Figure 8C illustrates an example of a stack of inverter capacitors 870a, 870b, 870c with intervening PCM 802a, 802b, consistent with embodiments of the present disclosure. Inverter capacitors 870a, 870b, 870c may be arranged in a layered stack, with PCM 802a, 802b positioned between each capacitor as a thermal buffer. PCM 802a, 802b may be sandwiched between inverter capacitors 870a, 870b, 870c and / or between metal outer layers such as aluminum, which may enhance heat absorption and dissipation during high-load or transient events. The metal layers may provide high thermal conductivity, enabling transfer of heat from the capacitors to PCM 802a, 802b, while PCM 802a, 802b absorbs excess thermal energy as it undergoes a phase change. This configuration may help maintain a more consistent temperature profile across the stack and prolong the duration of effective cooling, protecting the capacitors from thermal spikes. In some embodiments, the stack may be modular, allowing for easy replacement or customization of PCM materials to suit specific operational requirements or environmental conditions. For example, each of PCM 802a, 802b may be replaceable.

[0102] Inverter capacitor component 800 or 850 may be mounted in epoxy. The epoxy may encapsulate inverter capacitor housing 804 as well. In some embodiments, PCM may be placed between an inverter capacitor and inverter capacitor housing 804. For example, epoxy may surround PCM 802 of Fig. 8A, PCM 852 of Fig. 8B, and / or PCM 802a, 802b of Fig. 8C. In some embodiments, epoxy may contain PCM as an additive component to help distribute or redirect heat generated by an inverter capacitor. Any of these embodiments of PCM with epoxy or inverter capacitors may be used in any combination thereof. For example, one PCM may be used to surround an inverter capacitor, and another PCM may be used as an additive in epoxy that surrounds the inverter capacitor or inverter capacitor housing 804.

[0103] Disclosed systems and methods may include a propeller system for an aircraft (e.g., a VTOL as disclosed). A drive shaft may be configured to drive a propeller (e.g., lift propeller 112 or tilt propeller 114 of Figs. 1A-1B) in the aircraft. An engine may be configured to rotate the drive shaft. The engine may include a motor. An inverter may be electrically coupled to the motor. The inverter may include a stack of inverter capacitors, and intervening PCM (e.g., intervening PCM 802a, 802b in Fig. 8C) for the inverter capacitors.

[0104] It should be understood that any combination of PCM materials in any configuration as shown with respect to Figs. 2-8B may be used in any combination in a VTOL engineAgent Ref. No. 16498-0015-00304 and / or propeller system, such as that described with respect to Figs. 1A-1B. For example, the PCM in the containers in Fig. 2-3, end bell 402 in Figs. 4-5, a cartridge, engine oil sump 602 in Fig. 6, housing in Fig. 7, and / or inverter capacitor housing 804 in Figs. 8A-8C may be used in any combination in a VTOL engine and / or propeller system as described herein. In one non-limiting example, an aircraft may be configured to house PCM in the end bell, in a heat exchanger end tank, and in part of the housing surrounding a motor to provide multiple points of heat exchange for the cooling fluid during different flight conditions. Since the PCM may be positioned within different locations in the aircraft (e.g., in a propeller system), there is nothing to prevent the combined use of PCM in the different locations. This enables use of PCM in any combination of the implementations described herein. The combination of various configurations of PCM in a VTOL engine and / or propeller system may help to further enhance heat exchange and cooling during high temperature conditions or during emergencies. Further, such combinations may enable modular control on cooling and managing excess heat in the aircraft (e.g., from an engine motor during lift configuration).

[0105] Figs. 9 A and 9B are graphical depictions of a reduction in temperature of components of a propeller system using PCM, consistent with embodiments of the present disclosure. The components and PCM may include any components or PCM described previously or depicted in Figs. 2-8B. These figures demonstrate the effectiveness of PCM integration in mitigating thermal spikes and maintaining safe operating temperatures across various subsystems in VTOLs.

[0106] In Fig. 9A, plot 902 shows an example of operational activity level of the engine (e.g. engine 202) over time using two metrics. For example, the metric may be torque, speed, power units, etc. For example, torque may include emergency torque or average torque of the drive shaft for the propeller motor. Plot 904 shows an example of temperature changes of three different system components (e.g., engine, heat exchanger, oil, etc.) with PCM (solid lines) and without PCM (dashed lines). Plot 904 corresponds in time with plot 902. The temperature increases with operational activity level of the engine. The actual values shown in plots 902 and 904 are for illustrative purposes only.

[0107] In plot 904, the temperature of each component rises during heightened operational activity level of the engine. When operational activity level decreases, the temperature of the components gradually reduces. During a large operational activity level (e.g., during take-off of VTOL), the temperature may rise rapidly, as in the right portion of plot 904. Failure of a part, blocked airflow, or similar problems may occur. When this occurs, a predetermined temperature threshold may be reached, initiating phase changes within the PCM. As shown inAgent Ref. No. 16498-0015-00304 plot 904, the PCM results in a marked reduction in the temperature rise of each of the three components once the predetermined threshold has been reached. In practice, this provides a backup cooling mechanism to prevent overheating of system components. Furthermore, a failure of a component may cause a rapid rise in temperature, which may be regulated by PCM in the system, preventing sudden overheating and damage of components. The staged activation of PCM, such as when multiple PCMs with different phase change temperatures are used, may allow for sequential absorption of heat and prolong the duration of effective cooling.

[0108] In Fig. 9B, a plot of oil temperature is shown for different phases of flight in a VTOL in an example failure scenario. In this scenario, engine failure 952 may occur after hover phase 954, outbound transition phase 956, climb phase 958, descent phase 960, or inbound transition phase 962. Engine failure 952 may represent a scenario in which a part failure has caused engine to overheat, leading to emergency hover down phase 964. Without PCM for backup cooling, the temperature may have risen following a steep climb shown by dashed line 966, which quickly surpasses oil temperature limit 968. This could have severe consequences for any system components sensitive to high temperatures. Instead, with PCM for backup cooling, the temperature rises significantly more slowly according to solid line 970, staying well below oil temperature limit 968. The additional cooling capacity may provide, e.g., the time needed for an aircraft to land safely even in the absence of a functional primary cooling system. PCM for this purpose may be implemented according to any embodiments of the present disclosure, as described previously or shown in Figs. 2-8C. The modularity and distributed placement of PCM containers, such as in oil sumps, heat exchangers, or inverter assemblies, may allow for tailored thermal management that addresses the specific needs of each subsystem in a VTOL.

[0109] The following is an example implementation of some of the embodiments presented herein. The predetermined threshold may be, e.g., 100 °C for a PCM in the engine. When a VTOL takes off, a rise in temperature may occur due to a heightened engine demand and if a problem occurs such as a reduced airflow through the heat exchanger. The temperature of oil, which may have a limit of 110 °C may reach 100 °C and the PCM may begin changing phase. The temperature rise may slow drastically or be eliminated. The PCM continues changing phase due to input of heat from the engine activity. Then the liftoff finishes, and the aircraft enters a relatively lower demand cruise configuration. In this mode, increased airflow through the heat exchanger coupled with lower engine demand results in removing heat from the system. As heat is removed, the temperature in the oil begins to drop and PCM releasesAgent Ref. No. 16498-0015-00304 heat. Heat from the oil is released through the heat exchanger, and gradually the PCM reverts back to its original phase, and the temperature returns to baseline levels. This presents an example implementation of some of the above embodiments to demonstrate how various uses of PCM may provide a backup cooling system in a vehicle, particularly a VTOL.

[0110] A computer-readable medium, for example a non -transitory computer-readable medium, may be provided that stores instructions for one or more processors of a controller for performing methods according to 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 for performing any of the above disclosed processes in part or in their entirety. Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, hard disk, solid-state drive, magnetic tape, or any other magnetic data storage medium, a Compact Disc Read-Only Memory (CD-ROM), any other optical data storage medium, any physical medium with patterns of holes, a Random Access Memory (RAM), a Programmable Read-Only Memory (PROM), and Erasable Programmable Read-Only Memory (EPROM), a FLASH-EPROM or any other flash memory, Non-Volatile Random Access Memory (NVRAM), a cache, a register, any other memory chip or cartridge, and networked versions of the same. The one or more processors can include any combination of any number of a central processing unit (CPU), a graphics processing unit (GPU), a neural processing unit (NPU), a microcontroller unit (MCU), an optical processor, a programmable logic controller, a microcontroller, a microprocessor, a digital signal processor, an intellectual property (IP) core, a Programmable Logic Array (PLA), a Programmable Array Logic (PAL), a Generic Array Logic (GAL), a Complex Programmable Logic Device (CPLD), a Field- Programmable Gate Array (FPGA), a System On Chip (SoC), an Application-Specific Integrated Circuit (ASIC), or the like. In some embodiments, the one or more processors can also be a set of processors grouped as a single logical component.

[0111] Embodiments of the present disclosure may be described with respect to the following clauses:1. A propeller system for an aircraft, comprising: a drive shaft configured to drive a propeller of the aircraft; an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine, the heat exchanger comprising an air inlet, an air outlet, and a first side surface between the air inlet and the air outlet; and a first container storing a phase change material, the first container being thermally coupled to the heat exchanger,Agent Ref. No. 16498-0015-00304 wherein the first container is mechanically coupled to the first side surface.2. The propeller system of clause 1, wherein the propeller system comprises a lift propeller.3. The propeller system of clause 1, wherein the propeller system comprises a tilt propeller.4. The propeller system of any of clauses 1 to 3, wherein the heat exchanger is mechanically coupled to a housing of the engine.5. The propeller system of any of clauses 1 to 4, wherein at least a portion of an air flow path from the air inlet to the air outlet runs parallel to the first side surface.6. The propeller system of any of clauses 1 to 5, further comprising a second side surface between the air inlet surface and the air outlet surface.7. The propeller system of clause 6, wherein the first container is mechanically coupled to the second side surface.8. The propeller system of clause 6, wherein the first container comprises a first sub-container mechanically coupled to the first side surface and a second sub-container mechanically coupled to the second side surface.9. The propeller system of any of clauses 6 to 8, further comprising a second container storing the phase change material, the second container being mechanically coupled to the second side surface, wherein the second is separate from the first container.10. The propeller system of any of clauses 1 to 9, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than a normal operating temperature of the heat exchanger.11. The propeller system of any of clauses 1 to 10, wherein the phase change material comprises a plurality of phase changing materials.12. A propeller system for an aircraft, comprising: a drive shaft configured to drive a propeller of the aircraft; an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine; a container storing phase change material; and a pipe thermally coupled to the engine, the heat exchanger, and the container, wherein pipe is configured to deliver cooling fluid from the engine, to the heat exchanger, to the container, and back to the engine.13. The propeller system of clause 12, wherein the propeller system comprises a lift propeller.14. The propeller system of clause 12, wherein the propeller system comprises a tilt propeller.Agent Ref. No. 16498-0015-0030415. The propeller system of any of clauses 12 to 14, wherein the heat exchanger is mechanically coupled to a housing of the engine.16. The propeller system of any of clauses 12 to 15, wherein the container comprises a plurality of separated sub-containers.17. The propeller system of any of clauses 12 to 16, wherein the pipe comprises a plurality of first inlet pipes and a plurality of first outlet pipes configured to deliver the cooling fluid from the plurality of first inlet pipes to the heat exchanger to the plurality of first outlet pipes.18. The propeller system of any of clauses 12 to 17, wherein the pipe comprises a plurality of second inlet pipes and a plurality of second outlet pipes configured to deliver the cooling fluid from the plurality of second inlet pipes to the container to the plurality of second outlet pipes.19. The propeller system of any of clauses 12 to 18, wherein the pipe comprises a first bypass pipe having a first bypass valve configured to bypass the heat exchanger.20. The propeller system of any of clauses 12 to 19, wherein the pipe comprises a second bypass pipe having a second bypass valve configured to bypass the container.21. The propeller system of any of clauses 12 to 20, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than a normal operating temperature of the heat exchanger.22. The propeller system of any of clauses 12 to 21, wherein the phase change material comprises a plurality of phase changing materials.23. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a housing surrounding the motor, the housing comprising an end bell located at an end of the motor, wherein the end bell comprises a chamber containing a phase change material.24. The propeller system of clause 23, wherein the end bell is thermally coupled to an inverter.25. The propeller system of clause 23 or 24, wherein the propeller system comprises lift propeller.26. The propeller system of clause 23 or 24, wherein the propeller system comprises tilt propeller.27. The propeller system of any of clauses 23 to 26, wherein the end bell comprises a plurality of separated chambers containing the phase change material.Agent Ref. No. 16498-0015-0030428. The propeller system of any of clauses 23 to 27, wherein the phase change material is separated from rotating components of the motor by a partition.29. The propeller system of any of clauses 23 to 28, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than a normal operating temperature of the heat exchanger.30. The propeller system of any of clauses 23 to 29, wherein the phase change material comprises a plurality of phase changing materials.31. The propeller system of any of clauses 23 to 30, wherein the phase change material is configured to release heat conductively through the end bell.32. A propeller system for an aircraft, comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a housing surrounding the motor, the housing comprising an end bell located at an end of the motor and mechanically coupled to a thermal plate between the end bell and the motor, wherein the thermal plate contains a phase change material.33. The propeller system of clause 32, wherein the propeller system comprises lift propeller.34. The propeller system of clause 32, wherein the propeller system comprises tilt propeller.35. The propeller system of any of clauses 32 to 34, further comprising a heat exchanger thermally coupled to the engine.36. The propeller system of clause 35, wherein the heat exchanger is mechanically coupled to a housing of the engine.37. The propeller system of any of clauses 32 to 36, wherein the thermal plate comprises a plurality of separated sub -containers containing the phase change material.38. The propeller system of any of clauses 32 to 37, wherein the thermal plate comprises a cooling fluid inlet and a cooling fluid outlet.39. The propeller system of clause 38, wherein the cooling fluid inlet is configured to receive cooling fluid from a thermostatic diverting valve.40. The propeller system of clause 38 or 39, wherein the cooling fluid outlet is configured to send cooling fluid through a thermostatic diverting valve.41. The propeller system of any of clauses 32 to 40, wherein the phase change material is configured to change phase at a threshold temperature higher than a normal operating temperature of the heat exchanger.42. The propeller system of any of clauses 32 to 41, wherein the phase change material comprises a plurality of phase changing materials.Agent Ref. No. 16498-0015-0030443. A propeller system for an aircraft, comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a housing surrounding the motor, the housing comprising an engine oil sump, wherein the engine oil sump is mechanically coupled to an insert comprising a phase change material.44. The propeller system of clause 43, wherein the insert is in direct contact with oil.45. A propeller system for an aircraft, comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a housing surrounding the motor, the housing comprising a phase change material, wherein the phase change material is configured to be in direct contact with oil.46. The propeller system of clause 45, wherein the phase change material is located in the housing of a stator of the motor.47. A propeller system for an aircraft, comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; an inverter electrically coupled to the motor, the inverter comprising an inverter capacitor, wherein the inverter capacitor is covered on a surface by a phase change material.48. A propeller system for an aircraft, comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; an inverter electrically coupled to the motor, the inverter comprising: an inverter capacitor; a housing for the inverter capacitor, wherein the housing is thermally coupled to a phase change material.49. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 1 to 48, the method comprising operating the engine during takeoff or landing of the aircraft.50. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 49.51. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller of the aircraft;Agent Ref. No. 16498-0015-00304 an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine, the heat exchanger comprising an air inlet and an air outlet; and a first container storing a phase change material, the first container being thermally coupled to the heat exchanger, wherein the first container is thermally coupled to the heat exchanger.52. The propeller system of clause 51, wherein the propeller is a lift propeller.53. The propeller system of clause 51, wherein the propeller is a tilt propeller.54. The propeller system of any one of clauses 51 to 53, wherein the heat exchanger is mechanically coupled to a housing of the engine, and the first container is thermally coupled to the heat exchanger.55. The propeller system of any one of clauses 51 to 54, wherein the heat exchanger comprises one or more side surfaces between the air inlet and the air outlet, wherein the first container is thermally coupled to at least one of the one or more side surfaces.56. The propeller system of clause 55, wherein the first container is thermally coupled to a plurality of the one or more side surfaces.57. The propeller system of clause 55 or 56, further comprising: a second container storing the phase change material, wherein the first container is thermally coupled to a first side surface of the one or more side surfaces, and the second container is thermally coupled to a second side surface of the one or more side surfaces, wherein the first side surface is different from the second side surface.58. The propeller system of any one of clauses 51 to 57, wherein the first container comprises a plurality of sub-containers thermally coupled to the heat exchanger.59. The propeller system of any one of clauses 51 to 58, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than an operating temperature of the heat exchanger.60. The propeller system of any one of clauses 51 to 59, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.61. The propeller system of clause 60, wherein a phase change temperature of the phase change material is an average of different phase change temperatures corresponding to each of the different phase change materials.62. The propeller system of any one of clauses 51 to 61, wherein the first container is removable for maintenance or replacement.Agent Ref. No. 16498-0015-0030463. The propeller system of any one of clauses 51 to 62, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.64. The propeller system of any one of clauses 51 to 63, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the heat exchanger.65. The propeller system of any one of clauses 51 to 64, wherein the heat exchanger includes an end tank and the first container is adjacent to or integrated with the end tank to facilitate heat exchange between the end tank and the phase change material.66. The propeller system of any one of clauses 51 to 65, wherein the first container is encapsulated by an epoxy.67. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 51 to 66, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.68. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 67.69. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller of the aircraft; an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine; a container storing a phase change material; and a pipe system thermally coupled to the engine, the heat exchanger, and the container, wherein the pipe system is configured to deliver a cooling fluid from the engine, to the heat exchanger, to the container, and back to the engine.70. The propeller system of clause 69, wherein the propeller is a lift propeller.71. The propeller system of clause 69, wherein the propeller is a tilt propeller.72. The propeller system of any one of clauses 69 to 71, wherein the heat exchanger is mechanically coupled to a housing of the engine for heat exchange between the heat exchanger and the engine.73. The propeller system of any one of clauses 69 to 72, wherein the container comprises a plurality of separate sub-containers for storing the phase change material.74. The propeller system of any one of clauses 69 to 73, wherein the pipe system comprises a plurality of first inlet pipes and a plurality of first outlet pipes configured to deliver the cooling fluid from the plurality of first inlet pipes to the heat exchanger to the plurality of first outlet pipes.Agent Ref. No. 16498-0015-0030475. The propeller system of any one of clauses 69 to 74, wherein the pipe system comprises a plurality of second inlet pipes and a plurality of second outlet pipes configured to deliver the cooling fluid from the plurality of second inlet pipes to the container to the plurality of second outlet pipes.76. The propeller system of any one of clauses 69 to 75, wherein the pipe system comprises a first bypass valve configured to operate in a first state to direct the cooling fluid through the heat exchanger, and in a second state to direct the cooling fluid through a first bypass pipe to bypass the heat exchanger.77. The propeller system of any one of clauses 69 to 76, wherein the pipe system comprises a second bypass valve configured either to direct the cooling fluid through the container, or to direct the cooling fluid through a second bypass pipe to bypass the container.78. The propeller system of clause 77, further comprising a temperature sensor configured to actuate one or more of the first bypass valve or the second bypass valve, based on a temperature of the cooling fluid.79. The propeller system of any one of clauses 69 to 78, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than an operating temperature of the heat exchanger.80. The propeller system of any one of clauses 69 to 79, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.81. The propeller system of clause 80, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.82. The propeller system of any one of clauses 69 to 81, wherein the container is configured to be removable for maintenance or replacement.83. The propeller system of any one of clauses 69 to 82, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.84. The propeller system of any one of clauses 69 to 83, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the heat exchanger.85. The propeller system of any one of clauses 69 to 84, further comprising a cartridge filter operably coupled to one or more pipes of the pipe system such that the cooling fluid flows through the cartridge filter, the cartridge filter comprising the phase change material.Agent Ref. No. 16498-0015-0030486. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 69 to 85, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.87. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 86.88. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an end bell located at an end of the motor, the end bell comprising a chamber containing a phase change material.89. The propeller system of clause 88, wherein the end bell is thermally coupled to an inverter.90. The propeller system of clause 88 or 89, wherein the propeller is a lift propeller.91. The propeller system of clause 88 or 89, wherein the propeller is a tilt propeller.92. The propeller system of any one of clauses 88 to 91, wherein the end bell comprises a plurality of separate chambers containing the phase change material.93. The propeller system of any one of clauses 88 to 92, wherein the housing comprises a partition separating the phase change material from rotating components of the motor.94. The propeller system of any one of clauses 88 to 93, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than an operating temperature of an engine component.95. The propeller system of any one of clauses 88 to 94, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.96. The propeller system of clause 95, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.97. The propeller system of any one of clauses 88 to 96, wherein the phase change material is configured to release heat conductively through the end bell.98. The propeller system of any one of clauses 88 to 97, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.99. The propeller system of any one of clauses 88 to 98, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the housing.Agent Ref. No. 16498-0015-00304100. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 88 to 99, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.101. A computer-readable medium that stores a set of instructions that is executable by at least one processor to cause the aircraft to perform the method of clause 100.102. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an end bell located at an end of the motor and thermally coupled to a thermal plate between the end bell and the motor, wherein the thermal plate comprises a phase change material.103. The propeller system of clause 102, wherein the propeller is a lift propeller.104. The propeller system of clause 102, wherein the propeller is a tilt propeller.105. The propeller system of any one of clauses 102 to 104, further comprising a heat exchanger thermally coupled to the engine.106. The propeller system of any one of clauses 102 to 105, wherein the heat exchanger is mechanically coupled to a housing of the engine.107. The propeller system of any one of clauses 102 to 106, wherein the thermal plate comprises a plurality of separate sub -containers comprising the phase change material.108. The propeller system of any one of clauses 102 to 107, wherein the thermal plate comprises a cooling fluid inlet and a cooling fluid outlet.109. The propeller system of clause 108, further comprising: a diverting valve configured to: direct a cooling fluid to the cooling fluid inlet when a temperature of the cooling fluid exceeds a predetermined temperature, and direct the cooling fluid to the end bell when the temperature is lower than or equal to the predetermined temperature.110. The propeller system of clause 109, wherein the diverting valve is a thermostatic diverting valve.111. The propeller system of any one of clauses 102 to 110, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.Agent Ref. No. 16498-0015-00304112. The propeller system of any one of clauses 102 to 111, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.113. The propeller system of clause 112, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.114. The propeller system of any one of clauses 102 to 113, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.115. The propeller system of any one of clauses 102 to 114, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the housing.116. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 102 to 115, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.117. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 116.118. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an engine oil sump thermally coupled to an insert comprising a phase change material.119. The propeller system of clause 118, wherein the propeller is a lift propeller.120. The propeller system of clause 118, wherein the propeller is a tilt propeller.121. The propeller system of any one of clauses 118 to 120, wherein the insert is configured to be in direct contact with oil in the engine oil sump.122. The propeller system of any one of clauses 118 to 121, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.123. The propeller system of any one of clauses 118 to 122, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.124. The propeller system of clause 123, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.Agent Ref. No. 16498-0015-00304125. The propeller system of any one of clauses 118 to 124, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.126. The propeller system of any one of clauses 118 to 125, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the housing.127. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 118 to 126, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.128. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 128.129. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a housing surrounding the motor, the housing comprising a container comprising a phase change material; and a heat exchanger thermally coupled to the engine, wherein the propeller system is configured to enable a cooling fluid to circulate between the heat exchanger, the engine, and the housing, and wherein the container is positioned to be in direct contact with a cooling fluid.130. The propeller system of clause 130, wherein the propeller is a lift propeller.131. The propeller system of clause 130, wherein the propeller is a tilt propeller.132. The propeller system of any one of clauses 129 to 131, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.133. The propeller system of any one of clauses 129 to 132 wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.134. The propeller system of clause 133, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.135. The propeller system of any one of clauses 129 to 134, wherein the container is located in one or more compartment of a stator, a rotor, or an inverter.136. The propeller system of any one of clauses 129 to 135, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.Agent Ref. No. 16498-0015-00304137. The propeller system of any one of clauses 129 to 136, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the heat exchanger.138. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 129 to 137, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.139. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 139.140. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a phase change material; and an inverter electrically coupled to the motor, the inverter comprising an inverter capacitor, wherein the inverter capacitor has a surface adjacent the phase change material.141. The propeller system of clause 140, wherein the propeller is a lift propeller.142. The propeller system of clause 140, wherein the propeller is a tilt propeller.143. The propeller system of any one of clauses 140 to 142, wherein the inverter capacitor and the phase change material are encapsulated within an epoxy.144. The propeller system of any one of clauses 140 to 143, wherein the phase change material has phase change temperature higher than an operating temperature of an engine component.145. The propeller system of any one of clauses 140 to 144, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.146. The propeller system of clause 145, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.147. The propeller system of any one of clauses 140 to 146, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.148. The propeller system of any one of clauses 140 to 147, wherein the phase change material has a phase change temperature higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the inverter.Agent Ref. No. 16498-0015-00304149. The propeller system of any one of clauses 140 to 148, further comprising a second inverter capacitor substantially parallel to the inverter capacitor.150. The propeller system of clause 149, further comprising: a second phase change material, the second inverter capacitor having a second surface adjacent the second phase change material.151. The propeller system of clause 150, wherein the first phase change material and the inverter capacitor are thermally coupled, and / or the second phase change material and the second inverter capacitor are thermally coupled.152. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 140 to 151, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.153. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 152.154. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; a phase change material; and an inverter electrically coupled to the motor, the inverter comprising: an inverter capacitor, and an inverter capacitor housing for the inverter capacitor, wherein the inverter capacitor housing and the phase change material are thermally coupled.155. The propeller system of clause 154, wherein the propeller is a lift propeller.156. The propeller system of clause 154, wherein the propeller is a tilt propeller.157. The propeller system of any one of clauses 154 to 156, further comprising a second inverter capacitor substantially parallel to the inverter capacitor, wherein the phase change material and the second inverter capacitor are thermally coupled.158. The propeller system of any one of clauses 154 to 157, wherein the phase change material is positioned between the inverter and the inverter capacitor housing.159. The propeller system of any one of clauses 154 to 158, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.Agent Ref. No. 16498-0015-00304160. The propeller system of any one of clauses 154 to 159, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.161. The propeller system of clause 160, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.162. The propeller system of any one of clauses 154 to 161, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.163. The propeller system of any one of clauses 154 to 162, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, the inverter, or the inverter capacitor.164. A method for operating an aircraft, the aircraft comprising the propeller system of any one of clauses 154 to 163, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.165. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of clause 164.

[0112] The foregoing description has been presented for purposes of illustration. It is not exhaustive and does not limit the invention to the precise forms or embodiments disclosed. Modifications and adaptations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed embodiments of the inventions disclosed herein.

Claims

Agent Ref. No. 16498-0015-00304CLAIMS:

1. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller of the aircraft; an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine, the heat exchanger comprising an air inlet and an air outlet; and a first container storing a phase change material, the first container being thermally coupled to the heat exchanger, wherein the first container is thermally coupled to the heat exchanger.

2. The propeller system of claim 1, wherein the propeller is a lift propeller.

3. The propeller system of claim 1, wherein the propeller is a tilt propeller.

4. The propeller system of any one of claims 1 to 3, wherein the heat exchanger is mechanically coupled to a housing of the engine, and the first container is thermally coupled to the heat exchanger.

5. The propeller system of any one of claims 1 to 4, wherein the heat exchanger comprises one or more side surfaces between the air inlet and the air outlet, wherein the first container is thermally coupled to at least one of the one or more side surfaces.

6. The propeller system of claim 5, wherein the first container is thermally coupled to a plurality of the one or more side surfaces.

7. The propeller system of claim 5 or 6, further comprising a second container storing the phase change material, wherein the first container is thermally coupled to a first side surface of the one or more side surfaces, and the second container is thermally coupled to a second side surface of the one or more side surfaces, wherein the first side surface is different from the second side surface.

8. The propeller system of any one of claims 1 to 7, wherein the first container comprises a plurality of sub-containers thermally coupled to the heat exchanger.

9. The propeller system of any one of claims 1 to 8, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than an operating temperature of the heat exchanger.

10. The propeller system of any one of claims 1 to 9, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.Agent Ref. No. 16498-0015-0030411. The propeller system of claim 10, wherein a phase change temperature of the phase change material is an average of different phase change temperatures corresponding to each of the different phase change materials.

12. The propeller system of any one of claims 1 to 11, wherein the first container is removable for maintenance or replacement.

13. The propeller system of any one of claims 1 to 12, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.

14. The propeller system of any one of claims 1 to 13, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the heat exchanger.

15. The propeller system of any one of claims 1 to 14, wherein the heat exchanger includes an end tank and the first container is adjacent to or integrated with the end tank to facilitate heat exchange between the end tank and the phase change material.

16. The propeller system of any one of claims 1 to 15, wherein the first container is encapsulated by an epoxy.

17. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 1 to 16, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.

18. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 17.

19. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller of the aircraft; an engine configured to rotate the drive shaft; a heat exchanger thermally coupled to the engine; a container storing a phase change material; and a pipe system thermally coupled to the engine, the heat exchanger, and the container, wherein the pipe system is configured to deliver a cooling fluid from the engine, to the heat exchanger, to the container, and back to the engine.

20. The propeller system of claim 19, wherein the propeller is a lift propeller.

21. The propeller system of claim 19, wherein the propeller is a tilt propeller.

22. The propeller system of any one of claims 19 to 21, wherein the heat exchanger is mechanically coupled to a housing of the engine for heat exchange between the heat exchanger and the engine.Agent Ref. No. 16498-0015-0030423. The propeller system of any one of claims 19 to 22, wherein the container comprises a plurality of separate sub-containers for storing the phase change material.

24. The propeller system of any one of claims 19 to 23, wherein the pipe system comprises a plurality of first inlet pipes and a plurality of first outlet pipes configured to deliver the cooling fluid from the plurality of first inlet pipes to the heat exchanger to the plurality of first outlet pipes.

25. The propeller system of any one of claims 19 to 24, wherein the pipe system comprises a plurality of second inlet pipes and a plurality of second outlet pipes configured to deliver the cooling fluid from the plurality of second inlet pipes to the container to the plurality of second outlet pipes.

26. The propeller system of any one of claims 19 to 25, wherein the pipe system comprises a first bypass valve configured to operate in a first state to direct the cooling fluid through the heat exchanger, and in a second state to direct the cooling fluid through a first bypass pipe to bypass the heat exchanger.

27. The propeller system of any one of claims 19 to 26, wherein the pipe system comprises a second bypass valve configured either to direct the cooling fluid through the container, or to direct the cooling fluid through a second bypass pipe to bypass the container.

28. The propeller system of claim 27, further comprising a temperature sensor configured to actuate one or more of the first bypass valve or the second bypass valve, based on a temperature of the cooling fluid.

29. The propeller system of any one of claims 19 to 28, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than an operating temperature of the heat exchanger.

30. The propeller system of any one of claims 19 to 29, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.

31. The propeller system of claim 30, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.

32. The propeller system of any one of claims 19 to 31, wherein the container is configured to be removable for maintenance or replacement.

33. The propeller system of any one of claims 19 to 32, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.Agent Ref. No. 16498-0015-0030434. The propeller system of any one of claims 19 to 33, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the heat exchanger.

35. The propeller system of any one of claims 19 to 34, further comprising a cartridge filter operably coupled to one or more pipes of the pipe system such that the cooling fluid flows through the cartridge filter, the cartridge filter comprising the phase change material.

36. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 19 to 35, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.

37. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 36.

38. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an end bell located at an end of the motor, the end bell comprising a chamber containing a phase change material.

39. The propeller system of claim 38, wherein the end bell is thermally coupled to an inverter.

40. The propeller system of claim 38 or 39, wherein the propeller is a lift propeller.

41. The propeller system of claim 38 or 39, wherein the propeller is a tilt propeller.

42. The propeller system of any one of claims 38 to 41, wherein the end bell comprises a plurality of separate chambers containing the phase change material.

43. The propeller system of any one of claims 38 to 42, wherein the housing comprising a partition separating the phase change material from rotating components of the motor.

44. The propeller system of any one of claims 38 to 43, wherein the phase change material is configured to change phase at a predetermined threshold temperature higher than an operating temperature of an engine component.

45. The propeller system of any one of claims 38 to 44, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.

46. The propeller system of claim 45, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.Agent Ref. No. 16498-0015-0030447. The propeller system of any one of claims 38 to 46, wherein the phase change material is configured to release heat conductively through the end bell.

48. The propeller system of any one of claims 38 to 47, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.

49. The propeller system of any one of claims 38 to 48, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the housing.

50. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 38 to 49, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.

51. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 50.

52. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an end bell located at an end of the motor and thermally coupled to a thermal plate between the end bell and the motor, wherein the thermal plate comprises a phase change material.

53. The propeller system of claim 52, wherein the propeller is a lift propeller.

54. The propeller system of claim 52, wherein the propeller is a tilt propeller.

55. The propeller system of any one of claims 52 to 54, further comprising a heat exchanger thermally coupled to the engine.

56. The propeller system of any one of claims 52 to 55, wherein the heat exchanger is mechanically coupled to a housing of the engine.

57. The propeller system of any one of claims 52 to 56, wherein the thermal plate comprises a plurality of separate sub-containers comprising the phase change material.

58. The propeller system of any one of claims 52 to 57, wherein the thermal plate comprises a cooling fluid inlet and a cooling fluid outlet.

59. The propeller system of claim 58, further comprising: a diverting valve configured to: direct a cooling fluid to the cooling fluid inlet when a temperature of the cooling fluid exceeds a predetermined temperature, and direct the cooling fluid to the end bell when the temperature is lower than or equal to the predetermined temperature.Agent Ref. No. 16498-0015-0030460. The propeller system of claim 59, wherein the diverting valve is a thermostatic diverting valve.

61. The propeller system of any one of claims 52 to 60, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.

62. The propeller system of any one of claims 52 to 61, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.

63. The propeller system of claim 62, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.

64. The propeller system of any one of claims 52 to 63, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.

65. The propeller system of any one of claims 52 to 63, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the housing.

66. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 52 to 65, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.

67. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 66.

68. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; and a housing surrounding the motor, the housing comprising an engine oil sump thermally coupled to an insert comprising a phase change material.

69. The propeller system of claim 68, wherein the propeller is a lift propeller.

70. The propeller system of claim 68, wherein the propeller is a tilt propeller.

71. The propeller system of any one of claims 68 to 70, wherein the insert is configured to be in direct contact with oil in the engine oil sump.

72. The propeller system of any one of claims 68 to 71, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.Agent Ref. No. 16498-0015-0030473. The propeller system of any one of claims 68 to 72, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.

74. The propeller system of claim 73, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.

75. The propeller system of any one of claims 68 to 74, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.

76. The propeller system of any one of claims 68 to 75, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the housing.

77. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 68 to 76, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.

78. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 77.

79. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a housing surrounding the motor, the housing comprising a container comprising a phase change material; and a heat exchanger thermally coupled to the engine, wherein the propeller system is configured to enable a cooling fluid to circulate between the heat exchanger, the engine, and the housing, and wherein the container is positioned to be in direct contact with a cooling fluid.

80. The propeller system of claim 79, wherein the propeller is a lift propeller.

81. The propeller system of claim 79, wherein the propeller is a tilt propeller.

82. The propeller system of any one of claims 79 to 81, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.

83. The propeller system of any one of claims 79 to 82 wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.Agent Ref. No. 16498-0015-0030484. The propeller system of claim 83, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.

85. The propeller system of any one of claims 79 to 84, wherein the container is located in one or more compartment of a stator, a rotor, or an inverter.

86. The propeller system of any one of claims 79 to 85, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.

87. The propeller system of any one of claims 79 to 86, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the heat exchanger.

88. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 79 to 87, the method comprising operating the engine of the propeller system during takeoff or landing of the aircraft.

89. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 88.

90. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, wherein the engine comprises a motor; a phase change material; and an inverter electrically coupled to the motor, the inverter comprising an inverter capacitor, wherein the inverter capacitor has a surface adjacent the phase change material.

91. The propeller system of claim 90, wherein the propeller is a lift propeller.

92. The propeller system of claim 90, wherein the propeller is a tilt propeller.

93. The propeller system of any one of claims 90 to 92, wherein the inverter capacitor and the phase change material are encapsulated within an epoxy.

94. The propeller system of any one of claims 90 to 93, wherein the phase change material has phase change temperature higher than an operating temperature of an engine component.

95. The propeller system of any one of claims 90 to 94, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.

96. The propeller system of claim 95, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.Agent Ref. No. 16498-0015-0030497. The propeller system of any one of claims 90 to 96, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.

98. The propeller system of any one of claims 90 to 97, wherein the phase change material has a phase change temperature higher than a predetermined operating temperature of one or more of the drive shaft, the engine, or the inverter.

99. The propeller system of any one of claims 90 to 98, further comprising a second inverter capacitor substantially parallel to the inverter capacitor.

100. The propeller system of claim 99, further comprising: a second phase change material, the second inverter capacitor having a second surface adjacent the second phase change material.

101. The propeller system of claim 100, wherein the first phase change material and the inverter capacitor are thermally coupled, and / or the second phase change material and the second inverter capacitor are thermally coupled.

102. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 90 to 101, the method comprising: operating the engine of the propeller system during takeoff or landing of the aircraft.

103. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 102.

104. A propeller system for an aircraft, the propeller system comprising: a drive shaft configured to drive a propeller in the aircraft; an engine configured to rotate the drive shaft, the engine comprising a motor; a phase change material; and an inverter electrically coupled to the motor, the inverter comprising: an inverter capacitor, and an inverter capacitor housing for the inverter capacitor, wherein the inverter capacitor housing and the phase change material are thermally coupled.

105. The propeller system of claim 104, wherein the propeller is a lift propeller.

106. The propeller system of claim 104, wherein the propeller is a tilt propeller.

107. The propeller system of any one of claims 104 to 106, further comprising: a second inverter capacitor substantially parallel to the inverter capacitor, wherein the phase change material and the second inverter capacitor are thermally coupled.Agent Ref. No. 16498-0015-00304108. The propeller system of any one of claims 104 to 107, wherein the phase change material is positioned between the inverter and the inverter capacitor housing.

109. The propeller system of any one of claims 104 to 108, wherein the phase change material has a phase change temperature higher than an operating temperature of an engine component.

110. The propeller system of any one of claims 104 to 109, wherein the phase change material comprises a plurality of different phase change materials characterized by different phase change temperatures.

111. The propeller system of claim 110, wherein a phase change temperature of the phase change material is an average temperature of different phase change temperatures corresponding to each of the different phase change materials.

112. The propeller system of any one of claims 104 to 111, wherein the phase change material comprises one or more of a paraffin, a fatty acid, a salt hydrate, or a metal alloy.

113. The propeller system of any one of claims 104 to 112, wherein the phase change material has a phase change temperature that is higher than a predetermined operating temperature of one or more of the drive shaft, the engine, the inverter, or the inverter capacitor.

114. A method for operating an aircraft, the aircraft comprising the propeller system of any one of claims 104 to 113, the method comprising operating the engine during takeoff or landing of the aircraft.

115. A computer-readable medium that stores a set of instructions that is executable by at least one processor of an aircraft to cause the aircraft to perform the method of claim 114.

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