Battery system and thermal-management system for craft

Abstract

A craft (100) includes a battery system (400) comprising a plurality of sets of batteries (902, 912, 922, 932). Each set of batteries is configured to provide power to a respective set of propeller motors (904, 914, 924, 934) from a plurality of propeller motors, where each respective set of propeller motors comprises (a) one or more port-side-propeller motors and (b) one or more starboard-side-propeller motors. For each respective set of propeller motors, the one or more starboard-side propellers associated with the one or more of the starboard-side-propeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port-side-propeller motors.

Description

BATTERY SYSTEM AND THERMAL-MANAGEMENT SYSTEM FOR CRAFTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 637,967, filed April 24, 2024, and titled “Battery System And Thermal -Managem ent System For Craft,” the contents of which are incorporated by reference herein in their entirety.BACKGROUND

[0002] Various craft are capable of taking off from, and landing on, water. Examples of such craft include crafts having extendible hydrofoils attached to the hull of the craft. For instance, a first (or “rear”) hydrofoil may be positioned towards the tail section of the craft, and a second (or “main”) hydrofoil may be positioned near the midsection of the craft, forward the first hydrofoil (e.g., proximate to the main wing of the craft). The hydrofoils may be controlled to extend and retract depending on the operating mode of the craft. For example, when airborne, the hydrofoils may be retracted towards the hull, and when hull-borne or foil-borne, the hydrofoils may be extended. Such craft may include one or more wings as well as a plurality of propellers on the one or more wings of the craft.

[0003] In some examples, such craft may be a wing-in-ground (WIG) effect craft. Such craft fly close to the ground or water surface by using the ground effect principle, where flying close to the surface reduces aerodynamic drag and increases lift. For example, the drag on the craft is reduced when its distance from the ground is within about the length of the aircraft’s wingspan.OVERVIEW

[0004] Aspects described herein are related to a battery system for powering propeller motors of a craft (such as aircraft, including craft that are capable of taking off from, and landing on, water) and a thermal-management system for a battery system of a craft.

[0005] In one aspect, disclosed herein is a craft that includes a hull, one or more wings coupled to the hull, a plurality of propellers arranged on the one or more wings, a plurality of propeller motors, and a battery system comprising a plurality of sets of batteries. The one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings. Further, the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboard- si de propellers. Still further, the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port- side-propeller motor is associated with a respective port-side propeller and each starboard- si depropeller motor is associated with a respective starboard- si de propeller. Each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propellermotors, where each respective set of propeller motors comprises (i) one or more of the port-side- propeller motors and (ii) one or more of the starboard-side-propeller motors. In an example, for each respective set of propeller motors, the one or more starboard- si de propellers associated with the one or more of the starboard-side-propeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port-side-propeller motors.

[0006] In another aspect, disclosed herein is a battery system for a craft. The craft comprises (i) hull, (ii) one or more wings coupled to the hull, wherein the one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings, (iii) a plurality of propellers arranged on the one or more wings, wherein the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboard-side propellers, (iv) a plurality of propeller motors, wherein the plurality of propeller motors comprises a plurality of port-side- propeller motors and a plurality of starboard side-propeller motors, wherein each port-side- propeller motor is associated with a respective port-side propeller and each starboard- si depropeller motor is associated with a respective starboard- si de propeller. The battery system comprises a plurality of sets of batteries. Each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propeller motors, wherein each respective set of propeller motors comprises (a) one or more of the port-side-propeller motors and (b) one or more of the starboard-side-propeller motors. In an example, for each respective set of propeller motors, the one or more starboard-side propellers associated with the one or more of the starboard- side-propeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port-side-propeller motors.

[0007] In another aspect, disclosed herein is a mounting system for a battery system. The mounting system comprises: (i) a starboard stringer; (ii) a port stringer; (iii) a plurality of crossbeams arranged between the starboard and port stringers; and (iv) a plurality of hangar brackets for supporting a plurality of sets of batteries of the battery system.

[0008] In another aspect, disclosed herein is a thermal -management system for a battery system of a craft. The battery system comprises a plurality of batteries, and the thermal-management system includes: (i) a plurality of battery vents, where each battery vent is (a) coupled to a respective battery of the battery system and (b) configured to transition from a sealed state to an open state at a threshold temperature; and (ii) a duct system comprising: (a) ducting arranged adjacent to the plurality of battery vents; and (b) a manifold (1) connecting the ducting arranged adjacent to the plurality of battery vents and (2) comprising one or more manifold exits, wherein the duct system is configured to exhaust gas away from the battery system when one or more ofthe battery vents are in the open state.

[0009] In another aspect, disclosed herein is a craft comprising (i) a battery system and (ii) a thermal-management system. The battery system includes a plurality of batteries. Further, the thermal-management system includes: (i) a plurality of battery vents, wherein each battery vent is (a) coupled to a respective battery of the battery system and (b) configured to transition from a sealed state to an open state at a threshold temperature; and (ii) a duct system comprising: (a) ducting arranged adjacent to the plurality of battery vents; and (b) a manifold (1) connecting the ducting arranged adjacent to the plurality of battery vents and (2) comprising one or more manifold exits, wherein the duct system is configured to exhaust gas away from the battery system when one or more of the battery vents are in the open state.

[0010] In another aspect, disclosed herein is a duct system for a thermal-management system for a battery system of a craft. The battery system comprises a plurality of batteries and the thermal-management system comprises a plurality of battery vents. The duct system includes: (a) ducting arranged adjacent to the plurality of battery vents; and (b) a manifold (1) connecting the ducting arranged adjacent to the plurality of battery vents and (2) comprising one or more manifold exits, wherein the duct system is configured to exhaust gas away from the battery system when one or more of the battery vents are in an open state.

[0011] One of ordinary skill in the art will appreciate these as well as numerous other aspects in reading the following disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are included to provide a further understanding of the claims, are incorporated in, and constitute a part of this specification. The detailed description and illustrated examples described serve to explain the principles defined by the claims.

[0013] Figure 1 A depicts a perspective view of a craft, according to an example of the present disclosure.

[0014] Figure IB depicts a top view of a craft, according to an example of the present disclosure.

[0015] Figure 1C depicts a side view of a craft, according to an example of the present disclosure.

[0016] Figure ID depicts a front view of a craft, according to an example of the present disclosure.

[0017] Figure IE illustrates a perspective view of an example of a craft, according to an example of the present disclosure.

[0018] Figure 2 illustrates an example main hydrofoil deployment system of a craft, according to an example of the present disclosure.

[0019] Figure 3 illustrates an example rear hydrofoil deployment system of a craft, according to an example of the present disclosure.

[0020] Figure 4 depicts an example battery system of a craft, according to an example of the present disclosure.

[0021] Figure 5 depicts an example control system of a craft, according to an example of the present disclosure.

[0022] Figure 6A depicts a craft in a hull-borne mode of operation, according to an example of the present disclosure.

[0023] Figure 6B depicts a craft in a hydrofoil-borne maneuvering mode of operation, according to an example of the present disclosure.

[0024] Figure 7A depicts a craft in a hydrofoil-borne takeoff mode of operation, according to an example of the present disclosure.

[0025] Figure 7B is a graph that depicts various lift forces acting on a craft, according to an example of the present disclosure.

[0026] Figure 8 depicts a craft in a wing-borne mode of operation, according to an example of the present disclosure.

[0027] Figure 9A depicts a schematic of an example battery system and sets of motors, according to an example of the present disclosure.

[0028] Figure 9B depicts example coverage areas of propellers, according to an example of the present disclosure.

[0029] Figure 9C depicts example coverage areas of propellers, according to an example of the present disclosure.

[0030] Figure 9D depicts a schematic of an example battery system and sets of motors, according to an example of the present disclosure.

[0031] Figure 9E depicts a schematic of an example battery system and sets of motors, according to an example of the present disclosure.

[0032] Figure 9F depicts a schematic of an example battery system and sets of motors, according to an example of the present disclosure.

[0033] Figure 10A depicts a perspective view of an example battery, according to an example of the present disclosure.

[0034] Figure 10B depicts a perspective view of an example battery power management unit (BPMU), according to an example of the present disclosure.

[0035] Figure 10C depicts a perspective view of an example disconnect module, according to an example of the present disclosure.

[0036] Figure 10D depicts a perspective view of an example battery subsystem, according to an example of the present disclosure.

[0037] Figure 11 depicts a perspective view of an example battery system, according to an example of the present disclosure.

[0038] Figure 12 depicts a schematic of an example battery system and sets of motors, according to an example of the present disclosure.

[0039] Figure 13 depicts a perspective view of an example mounting system for a battery system, according to an example of the present disclosure.

[0040] Figure 14A illustrates a perspective view of an example hangar bracket, according to an example of the present disclosure.

[0041] Figure 14B illustrates a perspective view an example hangar clamp, according to an example of the present disclosure.

[0042] Figure 14C illustrates a perspective view of an example crossbeam hangar, according to an example of the present disclosure.

[0043] Figure 14D illustrates a perspective view of an example crossbeam, according to an example of the present disclosure.

[0044] Figure 14E illustrates a perspective view of an example stiffening bracket, according to an example of the present disclosure.

[0045] Figure 15A is a perspective view of an example battery bay of a craft in which a battery system is being installed, according to an example of the present disclosure.

[0046] Figure 15B is a perspective view of the example battery bay of Figure 15A at a second stage of installation of the battery system, according to an example of the present disclosure.

[0047] Figure 16A depicts an example floorboard configured to separate a battery bay from a passenger area, according to an example of the present disclosure.

[0048] Figure 16B depicts subsets of a battery system that may be installed through hatches of the floorboard of Figure 16A, according to an example of the present disclosure.

[0049] Figure 17 depicts example charge ports of a craft, according to an example of the present disclosure.

[0050] Figure 18 depicts example BPMUs, according to an example of the present disclosure.

[0051] Figure 19 depicts a perspective view of an example thermal -management system, according to an example of the present disclosure.

[0052] Figure 20A depicts a perspective view of an example battery vent in a sealed state, according to an example of the present disclosure.

[0053] Figure 20B depicts a perspective view of the battery vent of Figure 20A in an open state, according to an example of the present disclosure.

[0054] Figure 21 A depicts a perspective view of an example battery vent in a sealed state, according to an example of the present disclosure.

[0055] Figure 21B depicts a perspective view of the battery vent of Figure 21 A in an open state, according to an example of the present disclosure.

[0056] Figure 22 illustrates an example external vent configured to vent to an environment external to a craft, according to an example of the present disclosure.

[0057] Figure 23A depicts a perspective view of an example manifold vent, according to an example of the present disclosure.

[0058] Figure 23B illustrates the manifold vent of Figure 23 A in an open state, according to an example of the present disclosure.

[0059] Figure 24A depicts a perspective view of two example batteries and example corresponding duct sections, according to an example of the present disclosure.

[0060] Figure 24B depicts a cross section of two example batteries and an example corresponding duct section, according to an example of the present disclosure.

[0061] Figure 25 depicts an example expansion joint between two duct sections, according to an example of the present disclosure

[0062] Figure 26A depicts a perspective view of an example manifold, according to an example of the present disclosure.

[0063] Figure 26B depicts a perspective view of an example manifold, according to an example of the present disclosure.

[0064] Figure 26C depicts a perspective view of an example manifold, according to an example of the present disclosure.

[0065] Figure 27A is an illustration of example material flowing through ducting having an example dropout, according to an example of the present disclosure.

[0066] Figure 27b is an illustration of example material flowing through ducting having a vertical rise but not having a dropout, according to an example of the present disclosure.

[0067] Figure 28 A depicts a perspective view of a thermal-management system having example join tubes, according to an example of the present disclosure.

[0068] Figure 28B depicts a close-up view of an example join tube of Figure 28 A, according to an example of the present disclosure.

[0069] Figure 29A depicts a perspective view of a thermal-management system having example insulation, according to an example of the present disclosure.

[0070] Figure 29B depicts an example type of insulation, according to an example of the present disclosure.

[0071] Figure 29C depicts an example type of insulation, according to an example of the present disclosure.

[0072] Figure 30 depicts a cross-section of an example hull and cooling-fluid lines of an example thermal-management system, according to an example of the present disclosure.

[0073] Figure 31 depicts a perspective view of an example moving system for moving batteries of a battery system of a craft, according to an example of the present disclosure.

[0074] Figure 32 depicts a perspective view of an example battery holder of the example moving system of Figure 31, according to an example of the present disclosure.

[0075] Figure 33 depicts a perspective view of an example hoist system of the example moving system of Figure 31, according to an example of the present disclosure.

[0076] Figure 34A depicts a perspective view of an example lock of the example moving system of Figure 31, according to an example of the present disclosure.

[0077] Figure 34B depicts a perspective, cross-sectional view of an example lock of the example moving system of Figure 31, according to an example of the present disclosure.

[0078] The drawings are for the purpose of illustrating example embodiments, and it is to be understood that the present disclosure is not limited to the arrangements and instrumentalities shown in the drawings.DETAILED DESCRIPTION

[0079] Various examples of systems, devices, and / or methods are described herein. Any embodiment, implementation, and / or feature described herein as being an “example” is not necessarily to be construed as preferred or advantageous over any other embodiment, implementation, and / or feature unless stated as such. Thus, other embodiments, implementations, and / or features may be utilized, and other changes may be made without departing from the scope of the subject matter presented herein.

[0080] Accordingly, the examples described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations.

[0081] Further, unless the context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall embodiments, with the understanding that not all illustrated features are necessary for each embodiment.

[0082] Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order.

[0083] Further, terms such as “A coupled to B” or “A is mechanically coupled to B” do not require members A and B to be directly coupled to one another. It is understood that various intermediate members may be utilized to “couple” members A and B together.

[0084] Moreover, terms such as “substantially” or “about” that may be used herein, are meant that the recited characteristic, parameter, or value need not be achieved exactly but that deviations or variations, including, for example, tolerances, measurement error, measurement accuracy limitations and other factors known to skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0085] In the figures, like numerals can refer to like elements throughout the figures.I. Introduction

[0086] Aspects described herein are generally related to craft, such as aircraft, including craft that are capable of taking off from, and landing on, water. Examples of such craft include crafts having extendible hydrofoils attached to the hull of the craft. For instance, a first (or “rear”) hydrofoil may be positioned towards the tail section of the craft, and a second (or “main”) hydrofoil may be positioned near the midsection of the craft, forward the first hydrofoil (e.g.,proximate to the main wing of the craft). The hydrofoils may be controlled to extend and retract depending on the operating mode of the craft. For example, when airborne, the hydrofoils may be retracted towards the hull, and when hull-borne or foil-borne, the hydrofoils may be extended. The term “hull” is used throughout this description to refer to the main body of the craft. It is understood that this term is interchangeable with the term “fuselage,” among other possible terms, which is sometimes used to refer to the main body of aircraft.

[0087] In some examples, the craft may additionally or alternatively be a wing-in-ground (WIG) effect craft. Such craft fly close to the ground or water surface by using the ground effect principle, where flying close to the surface reduces aerodynamic drag and increases lift. For example, the drag on the craft is reduced when its distance from the ground is within about the length of the aircraft’s wingspan.

[0088] Aspects described herein are related to a battery system used for, at least in part, powering propeller motors of a craft (such as aircraft, including craft that are capable of taking off from, and landing on, water) and a thermal-management system for a battery system of a craft.

[0089] Existing battery systems for powering propeller motors of such craft and existing thermal-management systems for battery systems of such craft suffer from various drawbacks.

[0090] Turning first to existing battery systems for powering propeller motors, various battery systems and configurations of battery systems exist for powering propeller motors of such craft (perhaps along with other equipment to which battery system may also be connected). The existing battery systems typically include an individual controller for each propeller motor. Further, in some scenarios, the existing battery systems also include a separate battery subsystem for each propeller motor. However, the existing battery systems for powering propeller motors have numerous drawbacks.

[0091] For instance, existing systems may not provide adequate redundancy for the craft and, in particular, for potential scenarios where propeller motors may go offline. In an example, during operation of a craft, one or more individual motors may go offline for one reason or another (e.g., due to malfunction of the individual controller(s) and / or separate battery subsystem(s)). However, the one or more individual motors going offline may adversely impact the control and / or lift of the craft, and, in some scenarios, that craft may be unable to maintain sufficient lift and / or control of the craft for safely continuing the flight and thus may need to make an emergency landing. More particularly, depending on which motors go offline, the remaining motors in existing systems may be unable to account for the motors that went offline. In this regard, in existing systems, if a set of motors were to go offline, the propeller loss may lack symmetry or at least a desired or sufficient level of symmetry on the port side and starboard side of the craft. Suchpropeller loss lacking symmetry or at least a level of symmetry to which existing systems may be likely to be subject may further increase a chance that the craft may be unable to maintain sufficient lift and / or control of the craft when one or more individual motors going offline.

[0092] As another example drawback of existing systems, having individual controllers for each propeller motor requires a significant amount of control components for the craft. This significant amount of control components of existing systems may add to the weight and / or complexity of the craft. Other example drawbacks are possible as well.

[0093] Turning next to existing thermal-management systems for battery systems of such craft, battery systems may, for one reason or another, experience less than optimal performance in which a battery or set of batteries experience failure including potentially thermal runaway. Various thermal-management systems exist for dealing with such thermal-runaway situations. For instance, existing systems for dealing with thermal-runaway situations include firewall systems to isolate thermal-runaway issues (e.g., to protect the passengers from harm if a thermal runaway occurs), venting systems to dissipate gas resulting from thermal-runaway issues, and mechanisms for flooding the battery system to address thermal-runaway issues, among other possibilities.

[0094] However, the existing thermal-management systems for battery systems such as this have numerous drawbacks. For instance, existing thermal-management systems are not configured to vent to the individual battery level of the battery system. Further, existing thermal-management systems may not sufficiently isolate thermal-runaway issues (e.g., to protect the passengers from harm if a thermal runaway occurs), and existing thermal-management systems may not prevent or limit damage to other components of the craft near the battery system. Still further, the existing thermal-management systems may not adequately prevent or stop thermal runaway from spreading from one battery to other batteries. In this regard, in some cases, thermal runaway of one battery in a battery system may lead to a cascade of thermal runaway of other batteries. However, existing thermal-management systems may struggle to dissipate gas and heat effectively or efficiently enough to prevent thermal runaway from spreading from one battery to other batteries. Yet still further, in existing thermal-management systems, it is often difficult to keep battery temperatures low and / or constant over the charge and discharge cycles of the batteries, which may adversely impact the cycle life of the batteries of the craft. Other example drawbacks are possible as well.

[0095] To help address the aforementioned and other problems, disclosed herein is a new battery system for powering propeller motors of a craft and a new thermal-management system for a battery system of a craft.

[0096] In one aspect, disclosed herein is a craft that includes a hull, one or more wings coupled to the hull, a plurality of propellers arranged on the one or more wings, a plurality of propeller motors, and a battery system comprising a plurality of sets of batteries. The one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings. Further, the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboard- si de propellers. Still further, the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port- side-propeller motor is associated with a respective port-side propeller and each starboard- si depropeller motor is associated with a respective starboard- si de propeller. Each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propeller motors, where each respective set of propeller motors comprises (i) one or more of the port-side- propeller motors and (ii) one or more of the starboard-side-propeller motors. In an example, for each respective set of propeller motors, the one or more starboard- si de propellers associated with the one or more of the starboard-side-propeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port-side-propeller motors.

[0097] The disclosed battery system may provide various benefits over existing battery systems. For instance, pairing particular sets of motors with different sets of batteries provides for improved reliability, performance, and redundancy for the craft compared to existing systems. During operation, a battery or set of batteries may go offline for one reason or another, such as less than optimal performance of the battery or set of batteries (e.g., a malfunction of the battery or set of batteries). This in turn may cause the propeller motor(s) being powered by the battery or set of batteries to go offline. However, the battery system is configured such that, even if a set of batteries configured to provide power to a given set of propeller motors goes offline during operation of the craft and the given set of propeller motors ceases operation, the other propellers of the craft are able to maintain safe operation of the craft. In this regard, even though motors from the respective set of propeller motors may cease operation, the operation of the other propellers are sufficient to maintain lift and control of the craft. Turning back to existing battery systems for powering propeller motors, while controlling motors with respective individual controllers and / or separate battery subsystems may provide more individual control of each motor, existing craft may be more likely than the disclosed craft to experience motor loss where the remaining motors / propellers are unable to adequately compensate for the offline motors to maintain lift and control of the craft.

[0098] Further, compared to existing systems, the disclosed battery system that includes the disclosed pairing of particular sets of motors with different sets of batteries provides for an improved level of symmetry on the port side and starboard side of the craft even if a set of propeller motors goes offline.

[0099] Still further, by not having an individual controller for each motor, the disclosed battery system may be more efficient and have fewer components compared to existing systems. This may in turn reduce the weight and / or complexity of the disclosed craft compared to existing craft.

[0100] In another aspect, disclosed herein is a thermal-management system for a battery system of a craft. The battery system comprises a plurality of batteries, and the thermal-management system includes: (i) a plurality of battery vents, where each battery vent is (a) coupled to a respective battery of the battery system and (b) configured to transition from a sealed state to an open state at a threshold temperature; and (ii) a duct system comprising: (a) ducting arranged adjacent to the plurality of battery vents; and (b) a manifold (1) connecting the ducting arranged adjacent to the plurality of battery vents and (2) comprising one or more manifold exits, wherein the duct system is configured to exhaust gas away from the battery system when one or more of the battery vents are in the open state.

[0101] The disclosed thermal-management system may provide various benefits over existing thermal-management systems. For instance, the disclosed thermal-management system is able to dissipate gas and heat more effectively and / or efficiently than existing thermal-management systems. This helps to both (i) more effectively prevent thermal runaway from spreading from one battery to other batteries and (ii) more effectively prevent or limit damage to other components of the craft near the battery system (compared to existing thermal-management systems). In addition, the disclosed thermal-management system is also able to more effectively manage thermal conditions of the battery system during operation compared to existing thermal-management systems. By more effectively managing thermal conditions of the battery system during operation (e.g., keeping temperature lower and / or more constant during operation), the disclosed thermalmanagement system helps to improve the cycle life of batteries of the battery system of the craft.

[0102] These and other aspects are discussed in more detail in the passages that follow.II. Example Wing-In-Ground Effect Vehicles

[0103] Figures 1 A-1D illustrate different views of an example of a craft 100. As shown, some examples of the craft 100 include a hull 102, a main wing 104, a tail 106, a main hydrofoil assembly 108, and a rear hydrofoil assembly 110.A. Hull

[0104] Some examples of the craft 100 operate in a first waterborne mode for an extended period of time, during which the hull 102 is at least partially submerged in water. As such, some examples of the hull 102 are configured to be watertight, particularly for surfaces of the hull that contact the water during this first waterborne operational mode. Further, some examples of the hull 102, as well as the entirety of the craft 100, are configured to be passively stable on all axes when floating in water. To help achieve this, some examples of the hull 102 include a keel (or centerline) 112, which provides improved stability and other benefits described below. Some examples of the craft 100 include various mechanisms for adjusting the center of mass of the craft 100 so that the center of mass aligns with the center of buoyancy of the craft 100. For instance, in some examples, a battery system (described in further detail below in connection with Figure 4) of the craft 100 is electrically coupled to one or more moveable mounts. Some examples of the mounts are moved by one or more servo motors or the like. In some examples, a control system of the craft 100 is configured to detect a change in its center of buoyancy, for instance, by detecting a rotational change via an onboard gyroscope, and responsively operate the servo motors to move the battery system until the gyroscope indicates that the craft 100 has stabilized. Some examples of the craft 100 include a ballast system for pumping water or air to various tanks distributed throughout the hull 102 of the craft 100. The ballast system facilitates adjusting the center of mass of the craft 100 so that the center of mass aligns with the center of buoyancy of the craft 100. Other example systems may be used to control the center of mass of the craft 100 as well.

[0105] Additionally, or alternatively, some examples of the hull 102 are configured to reduce drag forces when both waterborne and wing-borne. For instance, some examples of the hull 102 have a high length-to-beam ratio (e.g., greater than or equal to 8), which facilitates reducing hydrodynamic drag forces when the craft 100 is under forward waterborne motion. Some examples of the keel 112 are curved or rockered to improve maneuverability when waterborne. Further, some examples of the hull 102 are configured to pierce the surface of waves (e.g., to increase passenger and crew comfort) by including a narrow, low-buoyancy bow portion of the hull 102.B. Wing and Distributed Propulsion System

[0106] As shown in Figures 1 A-1D, some examples of the main wing 104 include an outrigger 114 at each end of the main wing 104. The outriggers 114 (which are sometimes referred to as “wing-tip pontoons”) are configured to provide a buoyant force to the main wing 104 when submerged or when otherwise in contact with the water, which improves the stability of the craft 100 during waterborne operation. Some examples of the outriggers 114 may also includeintegrated pumps (e.g., propeller pumps) that facilitate providing thrust in some scenarios, as described in more detail below.

[0107] As shown in Figure ID, some examples of the main wing 104 have a gull-wing shape such that the outriggers 114 at the ends of the main wing 104 are at the lowest point of the main wing 104 and are positioned approximately level with (or slightly above) a waterline of the hull 102 when the hull 102 is waterborne.

[0108] Some examples of the main wing 104 have a high aspect ratio, which is defined as the ratio of the span of the main wing 104 to the mean chord of the main wing 104. In some examples, the aspect ratio of the main wing 104 is greater than or equal to five, or greater than or equal to six, but other example aspect ratios are possible as well. Such wings tend to have reduced pitch stability and maneuverability due to lower roll angular acceleration. These issues are ameliorated by various mechanisms described below. On the other hand, such wings tend to have increased roll stability and increased efficiency resulting from higher lift-to-drag ratios. Further, high aspect ratio wings provide a longer leading edge for the mounting of a distributed propulsion system along the wing.

[0109] As shown in the figures, some examples of the main wing 104 include a number of electric motor propeller assemblies 116 distributed across a leading edge of the main wing 104. This arrangement corresponds to a blown-wing propulsion system. Arranging the propeller assemblies 116 in this manner increases the speed of air moving over the main wing 104, which increases the lift generated by the main wing 104. This increase in lift allows the craft 100 to take off and become wing-borne at slower vehicle speeds. This facilitates, for example, taking off on water which can be difficult at higher speeds due to the various forces that would otherwise act on the craft 100.

[0110] The electric motor propeller assemblies 116 tend to be much lighter, less complex, and smaller than the liquid-fueled engines used on conventional craft. Some examples of the electric motor propeller assemblies 116 are controlled by an electronic speed controller and powered by an onboard battery system (e.g., a lithium-ion system, magnesium-ion system, lithium-sulfur system, etc.). Some examples of the electric motor propeller assemblies 116 are controlled by a fuel cell or a centralized liquid-fueled electricity generator. In some examples, the onboard electrical supply system includes multiple systems for supplying power during different operational modes, such as a first battery system configured to deliver large amounts of power during takeoff and a second system with a higher energy density but lower peak power capability for delivering sustained lower power during cruise operation (e.g., during hydrofoil waterborne operation or during wing-borne operation, each of which are described in further detail below).[OHl] In some examples, the positioning of the electric motor propeller assemblies 116 along the leading edge of the main wing 104 is determined based on a variety of factors including, but not limited to, (i) the total thrust for all modes of operation of the craft 100, (ii) the thrust generated by each individual propeller of the propeller assemblies 116, (iii) the radius of each propeller in the respective propeller assemblies 116, (iv) the tip clearance between each propeller and the surface of the water, and (v) the additional freestream speed over the main wing 104 required for operation.

[0112] As shown in the figures, in some examples, the number of propeller assemblies 116 is symmetrical across both sides of the hull 102. In some examples, the propeller assemblies 116 are identical. In some examples, the propeller assemblies 116 have different propeller radii or blade configurations along the span so long as the configuration is symmetrical across the hull 102. The different radii facilitate adequate propeller tip clearance from the water or vehicle structure. In some examples, the different propellers are optimized for different operational conditions, such as wing-borne cruise. The propeller placement and configuration may vary to increase the airflow over the main wing 104 or tail system 106 to improve controllability or stability. While twelve total propeller assemblies 116 are illustrated, the actual number of propeller assemblies 116 can vary based on the requirements of the craft 100.

[0113] In some examples, the propeller assemblies 116 have different pitch settings or variable pitch capabilities based on their position on the main wing 104. For instance, in some examples, a subset of the propeller assemblies 116 have fixed-pitch propellers sized for cruise speeds, while the remainder of the propeller assemblies 116 have fixed-pitch propellers configured for takeoff or can allow for varying the propeller’s pitch.

[0114] In some examples, different propeller assemblies 116 are turned off or have reduced rotational speeds during different modes of operation. For instance, during waterborne operation, one or more of the propeller assemblies 116 may be turned off or have reduced rotational speeds in a manner that generates asymmetrical thrust. This may create a yawing moment on the craft 100, allowing the craft 100 to turn without large bank angles and increasing the turning maneuverability of the craft 100. For instance, in order to yaw right, the craft 100 may increase the rotational speeds of the propellers of one or more of propeller assemblies 116g-l while decreasing the rotational speeds of the propellers of one or more of propeller assemblies 116a-f. Similarly, to yaw left, the craft 100 may increase the rotational speeds of the propellers of one or more of propeller assemblies 116a-f while decreasing the rotational speeds of the propellers of one or more of propeller assemblies 116g-l.

[0115] Similarly varying rotational speeds or propeller pitches may be used to yaw or roll the aircraft in flight or while foiling due to varied forces and lift distributions imposed over the wing and its control surfaces or in general used to tailor the lift distribution across the wing for optimized efficiency.

[0116] In some examples, the propeller assemblies may tilt to vector thrust either to provide directly more vertical lift or to change how the wing is blown depending on the mode of operation so as to tailor the blown lift distribution.

[0117] Some examples of the main wing 104 include one or more aerodynamic control surfaces, such as flaps 118 and ailerons 120. Some examples of these controls comprise movable hinged surfaces on the trailing or leading edges of the main wing 104 for changing the aerodynamic shape of the main wing 104. Some examples of the flaps 118 are configured to extend downward below the main wing 104 to reduce stall speed and create additional lift at low airspeeds, while some examples of the ailerons 120 are configured to extend upward above the main wing 104 to decrease lift on one side of the main wing 104 and induce a roll moment in the craft 100. In some examples, the ailerons 120 are additionally configured to extend downward below the main wing 104 in a flaperon configuration to help the flaps 118 generate additional lift on the main wing 104, which, in some examples, is used to either create a rolling moment or additional balanced lift depending on coordinated movement of both ailerons. Some examples of the flaps 118 and ailerons 120 include one or more actuators for raising and lowering the flaps 118 and ailerons 120. Within examples, the flaps 118 include one or more of plain flaps, split flaps, slotted flaps, Fowler flaps, slotted Fowler flaps, Gouge flaps, Junkers flaps, or Zap flaps. Further, in some examples, the flaps 118 (and the ailerons 120 when configured as flaperons) are positioned to be in the wake of one or more of the propeller assemblies 116. In some examples, the ailerons 120 are positioned so that they are in the wake of one or more of the propeller assemblies 116 to increase the effectiveness of the ailerons at low forward velocities. Some of the propeller assemblies 116 are positioned so that no ailerons 120 are in their wake to increase thrust on the outboard wing during a turn without inducing adverse yaw. For example, in a left turn, a normal airplane would have adverse yaw to the right as the right aileron is deflected down, increasing drag. In the present disclosure, however, the right propeller assembly outboard of the right aileron may have its thrust increased relative to the respective left propeller assembly, initiating a turn without adverse yaw.

[0118] Although in the example of Figures 1 A-D, the craft 100 is illustrated as including a single main wing 104, in other examples the craft 100 may include more than one wing. For instance, inthe example of FIG IE, the craft 100 includes a first wing 104a and a second wing 104b. Other examples are possible as well.C. Tail System

[0119] As illustrated in Figures 1A-1D, some examples of the tail 106 include a vertical stabilizer 122, a horizontal stabilizer 124, and one or more control surfaces, such as elevators 126. Similar to the flaps 118 and ailerons 120, some examples of the elevators 126 comprise movable hinged surfaces on the trailing or leading edges of the horizontal stabilizer 124 for changing the aerodynamic shape of the horizontal stabilizer 124 to control a pitch of the craft 100. Some examples of the horizontal stabilizer 124 are combined with the elevator 126, creating a fully articulating horizontal stabilizer (e.g., a stabilator). Raising the elevator 126 above the hinge point creates a net downward force on the tail system and causes the craft 100 to pitch upward. Lowering the elevators 126 below the hinge point creates a net upward force on the horizontal stabilizer 124 and causes the craft 100 to pitch downward. Some examples of the elevators 126 include actuators, which are operated by a control system of the craft 100 to raise and lower the elevators 126.

[0120] As illustrated in Figures 1 A-1D, some examples of tail 106 include a rudder 128. Some examples of the rudder 128 comprise a movable hinged surface on the trailing edge of the vertical stabilizer 122 for changing the aerodynamic shape of the vertical stabilizer 122 to control the yaw of the craft 100 when operating in an airborne mode. In some examples, the rudder 128 additionally changes a hydrodynamic shape of the hull 102 to control the yaw of the craft 100 when operating in a waterborne mode. To facilitate such hydrodynamic control, in some examples, the rudder 128 is positioned low enough on the tail 106 that the rudder 128 is partially or entirely submerged when the hull 102 is floating in water. For instance, the rudder 128 is positioned partially or entirely below the waterline of the hull 102. Some examples of the rudder 128 include one or more actuators, which are operated by a control system of the craft 100 to rotate the hinged surface of the rudder 128 to the left or right of the vertical stabilizer 122. Actuating the rudder 128 to the left (relative to the direction of travel) causes the craft 100 to yaw left. Actuating the rudder 128 to the right (relative to the direction of travel) causes the craft 100 to yaw right. As such, the rudder 128 may be used in combination with any of the other mechanisms disclosed herein for controlling the yaw of the craft 100, including in combination with the ailerons 120 during airborne operation and in combination with varying the rotational speeds of different ones of the propeller assemblies 116 to help improve the maneuverability of the craft 100 during waterborne operation.

[0121] Some examples of the tail 106 include one or more vertical stabilizers 122a, 122b, 122n, one or more horizontal stabilizers 124a, 124b, one or more control surfaces, such as elevators 126,and one or more tail flaps 127 for enhanced pitch control configured to exert enhanced net downward force on the tail system. It should be understood that although the figures show only two horizontal stabilizers, it is contemplated that more than two of each can be used within the scope of the present teachings. In some applications, it has been found that the transition from waterborne operation to airborne or wing-borne operation can require a larger pitching moment to overcome the larger drag forces existing between the hull 102 and / or the hydrofoil assemblies 108, 110 and the water. This phenomenon can further occur in wheeled aircraft configured for short takeoff and landing (STOL) operations. In this way, at low airspeeds, aerodynamic forces in conventional designs fail to produce sufficient downward force to permit sufficient pitching moment. To provide sufficient pitching moment to pitch the craft 100 upward, a conventional solution would be to increase the span of the tail so that the elevator generates more force; however, a resultant consequence of increasing the span of the tail is that the entire tail must be stronger and heavier, which can result in undesired reduction of payload and efficiency. However, the present configuration provides improved performance by providing a tail 106 having a first horizontal stabilizer 124a and a second horizontal stabilizer 124b. It should be understood that one or more additional horizontal stabilizers can be used.

[0122] In some examples, a first horizontal stabilizer 124a is a lower horizontal stabilizer relative to a second horizontal stabilizer 124b. However, it should be appreciated that the horizontal stabilizers in some examples can be interchanged for performance purposes (e.g., the disclosed structure of the first horizontal stabilizer 124a can be incorporated in the upper horizontal stabilizer and the disclosed structure of the second horizontal stabilizer 124b can be incorporated in the lower horizontal stabilizer). In some non-limiting examples, the structure, shape, and / or performance of each horizontal stabilizer can be tailored as desired such that the lower horizontal stabilizer (in this example, the first horizontal stabilizer 124a) is more likely to experience aerodynamic effect from being in the wake of the blown-wing propulsion system disclosed herein or associated wake produced by alternative propulsion systems. In this way, greater aerodynamic control and / or downwards lift can be generated during desired phases of operation.

[0123] Some examples of the horizontal stabilizers 124a, 124b include one or more aerodynamic control surfaces, such as tail flaps 127 and elevators 126, which may comprise movable hinged surfaces on the trailing or leading edges of the horizontal stabilizer 124a, 124b for changing the aerodynamic shape of the respective horizontal stabilizer 124a, 124b. It should be recognized that at least one of the horizontal stabilizers 124a, 124b can be sized, shaped, and / or spaced relative to a second of the horizontal stabilizers 124a, 124b to enhance or minimize theaerodynamic effect on the adjacent stabilizers. In this way, the aerodynamic flow, pressures, and / or forces can be used to improve the efficiency or effectiveness of the adjacent stabilizer. In some examples, at least one of the horizontal stabilizers 124a, 124b can be actuated in an opposing direction. In some embodiments, at least one of the horizontal stabilizers 124a, 124b can define a ratio of a surface area of the first horizontal stabilizer to a surface area of the second horizontal stabilizer in the range of 0.9 to 1.6. In some non-limiting example configurations, the surface area of the first horizontal stabilizer is 5.7 m2, the surface area of the second horizontal stabilizer is 3.9 m2, and both have a chord of about 1 m and a vertical separation of 1.8 m. In some embodiments, a vertical separation distance between the first horizontal stabilizer and the second horizontal stabilizer is in the range of 0.25 to 0.75 of the lower horizontal stabilizer span. In some examples, a vertical separation distance can be dependent on the required rudder authority and thus elevator size (driven by, e.g., yaw stability, or the need to counteract asymmetric thrust following powerplant failure). In some examples, a sweep offset moves the center of pressure further aft from the center of gravity, thus allowing the airfoil of the horizontal stabilizer to have less surface area overall, thus being smaller and lighter. In some examples, a dihedral in the bottom surface of the horizontal stabilizer adds stability. In some examples, the box tail design itself increases the efficiency due to the elimination of wingtip vortices of a typical tail. In some embodiments, a lower horizontal stabilizer may have approximately a 15% thickness-to-chord ratio to support the weight of the upper components, whereas the vertical and upper surfaces may be thinner, such as, for example, 10% thickness-to-chord ratio due to reduced structural load requirement, which enables the upper horizontal stabilizer to be more efficient (lower drag). It should be appreciated that the left and right elevator surfaces 126 can be controlled independently and / or differentially to create a rolling moment, thereby enabling the wing ailerons 120 to be made smaller. The smaller wing ailerons 120 further enable larger flaps 118. It should be appreciated that in some embodiments, using the vertical control surfaces 128a, 128b, 128n can change the pressure distribution across the elevator 126, for example, commanding a left 5 degree deflection in the left vertical control surface may move the mean pressure distribution left / right by a percentage of the elevator width.

[0124] Some examples of the tail flaps 127 are configured to selectively extend upward above the horizontal stabilizer 124 for changing a surface area, camber, aspect ratio, and / or shape of the horizontal stabilizer 124. The tail flaps 127 may include, for example, one or more of plain flaps, split flaps, slotted flaps, Fowler flaps, slotted or double-slotted Fowler flaps, Gouge flaps, Junkers flaps, or Zap flaps. That is, in some examples, tail flaps 127 serve to change an angle of attack of the horizontal stabilizer 124, change a chord line of the horizontal stabilizer 124, change a surfacearea of the horizontal stabilizer 124, and / or otherwise increase the net effective downwardly directed lift of the horizontal stabilizer 124. Such configurations effectively reduce the speed at which the horizontal stabilizer 124 becomes aerodynamically effective by creating additional net downward force at low airspeeds to aid in exerting a nose-up pitching moment of the craft 100. The elevators 126 may be configured for changing the aerodynamic shape of the horizontal stabilizer 124 to further control or vary a pitch of the craft 100.

[0125] In some examples operations, the tail flaps 127 are deployed for takeoff (e.g., transition from hydrofoil-borne mode to airborne mode) and landing (e.g., transition from airborne mode to hull-borne mode) to generate additional downforce on the tail system when additional pitch-up moment is required. Tail flaps 127 can be stowed for other phases of operation, such as hull-borne mode, to reduce downforce on the tail system and reduce drag.

[0126] In some examples, the elevators 126 are additionally configured to extend upward above the horizontal stabilizer 124 in a flaperon-like configuration (yet with elevators, rather than ailerons) to help the tail flaps 127 generate additional downward force on the horizontal stabilizer 124, which may be used to either create a pitching moment or additional balanced downward force. The tail flaps 127 and elevators 126 may each include one or more actuators 125 for raising and lowering the tail flaps 127 and elevators 126, singly or in combination. The actuators 125 can comprise any system configured to selectively actuate the associated system, such as but not limited to a flap track system (integrated into vertical stabilizers 122a, 122b, 122n, which can reduce complex hinge systems or external arms, thereby reducing wetted area and excrescences drag), an electric servo motor mounting within the vertical stabilizers 122a, 122b, 122n and / or horizontal stabilizers 124a, 124b, and / or a central vertical strut system generally mounted in the hull 102 or the fuselage of the craft 100 (to provide the potential for reduced cross-sectional area and associated drag).

[0127] Further, in some examples, the elevators 126 and / or the tail flaps 127 are positioned so that they are in the wake 129 of one or more of the propeller assemblies 116 of main wing 104. The elevators 126 and / or the tail flaps 127 may be positioned so that they are in the wake 129 of one or more of the propeller assemblies 116 to increase the effectiveness of the elevators at low forward velocities. In some examples, the propeller assemblies 116 are positioned so that no elevators 126 and / or tail flaps 127 are in the wake 129 to ensure consistent and / or predictable aerodynamic forces, independent of power application, are exerted during critical operational phases. In some examples, the propeller assemblies 116 are positioned so that the elevators 126 are in their wake 129 and the tail flaps 127 are not in the wake 129 (e.g., above the wake 129) and are exposed to clean air 131. It should be understood that positioning of the tail flaps 127 in thesecond horizontal stabilizer 124b, or at a distance above the center of gravity of the craft 100, will have the added unexpected benefit of creating additional nose-up pitching moment as a result of induced drag acting about the center of gravity causing the craft 100 to pitch upward.

[0128] Similar to the flaps 118 and the ailerons 120 of the main wing 104, some examples of the elevators 126 comprise movable hinged surfaces on the trailing or leading edges of the horizontal stabilizer 124 for changing the aerodynamic shape of the horizontal stabilizer 124 to control a pitch of the craft 100. The horizontal stabilizer 124 may be combined with the elevator 126, creating a fully articulating horizontal stabilizer (e.g., a stabilator). Raising the elevators 126 above the hinge point creates a net downward force on the tail system and causes the craft 100 to pitch upward. Lowering the elevators 126 below the hinge point creates a net upward force on the horizontal stabilizer 124 and causes the craft 100 to pitch downward. The elevators 126 may include actuators, which may be operated by a control system of the craft 100 in order to raise and lower the elevators 126.

[0129] In some examples, the tail 106 includes one or more rudders 128a, 128b, 128n. The rudders 128a, 128b, 128n may each comprise a movable hinged surface on the trailing edge of the corresponding vertical stabilizers 122a, 122b, 122n for changing the aerodynamic shape of the vertical stabilizer 122 to control the yaw of the craft 100 when operating in an airborne mode. It should be understood that rudders 128a, 128b, 128n can operate independently or in combination as desired. Moreover, in some examples, rudders 128a, 128b, 128n can be used as redundant systems, particularly useful in the event of one or more failures.

[0130] In some examples, the rudders 128a, 128b, 128n additionally change a hydrodynamic shape of the hull 102 to control the yaw of the craft 100 when operating in a waterborne mode. In order to facilitate such hydrodynamic control, the rudders 128a, 128b, 128n may be positioned low enough on the tail 106 that one or more of the rudders 128a, 128b, 128n is partially or entirely submerged when the hull 102 is floating in water. Namely, the rudders 128a, 128b, 128n may be positioned partially or entirely below a waterline of the hull 102. The rudders 128a, 128b, 128n may include one or more actuators, which may be operated by a control system of the craft 100 in order to rotate the hinged surface of the rudders 128a, 128b, 128n to the left or right of the vertical stabilizer 122. Actuating the rudders 128a, 128b, 128n to the left (relative to the direction of travel) causes the craft 100 to yaw left. Actuating the rudders 128a, 128b, 128n to the right (relative to the direction of travel) causes the craft 100 to yaw right. As such, the rudders 128a, 128b, 128n may be used in combination with any of the other mechanisms disclosed herein for controlling the yaw of the craft 100, including in combination with the ailerons 120 during airborne operationand in combination with varying the rotational speeds of different ones of the propeller assemblies 116 to help improve the maneuverability of the craft 100 during waterborne operation.

[0131] It should be understood that the fundamental shape of tail 106, having one or more vertical stabilizers 122a, 122b, 122n and one or more horizontal stabilizers 124a, 124b, can result in a box-like assembly, wherein the vertical stabilizers are generally coupled to the horizontal stabilizers to form a reinforced box-like construction. This box-like construction provides enhanced structural integrity that enables tail 106 of some examples to be lighter and / or smaller than otherwise constructed.

[0132] Some examples of the craft 100 include a distributed propulsion system on the tail 106, which may be similar to the distributed propulsion system of propeller assemblies 116 on the main wing 104. Such a distributed propulsion system may provide similar benefits of increasing the freestream velocity over the control surfaces (e.g., the elevators 126 and / or the rudder 128) to allow for increased pitch and yaw control of the craft 100 at lower travel speeds. When determining the number and size of propeller assemblies to include on the tail 106, one may apply the same factors described above when determining the number and size of propeller assemblies to include on the main wing 104.D. Hydrofoil Systems

[0133] As noted above, some examples of the craft 100 include a main hydrofoil assembly 108 and a rear hydrofoil assembly 110. In some examples, the main hydrofoil assembly 108 is positioned proximate to the middle or bow of the craft 100, and the rear hydrofoil assembly 110 is positioned proximate to the stern. For instance, some examples of the main hydrofoil assembly 108 is positioned between the bow and a midpoint (between the bow and stern) of the craft 100, and some examples of the rear hydrofoil assembly 110 is positioned below the tail 106 of the craft 100.

[0134] The main hydrofoil assembly 108 and the rear hydrofoil assembly 110 are configured to facilitate the breaking of contact between the hull of the craft and the water surface during takeoff, which can otherwise be challenging in some conventional craft designs. Some examples of the main hydrofoil assembly 108 and the rear hydrofoil assembly 110 are configured to be retractable, large enough to lift the entire craft out of the water and not impact the water surface, and to enable sustained operation in the hydrofoil-borne mode (where the entire weight of the craft is supported by the one or more hydrofoil assemblies).

[0135] Some examples of the main hydrofoil assembly 108 include a main hydrofoil 130, one or more main hydrofoil struts 132 that couple the main hydrofoil 130 to the hull 102, and one or more main hydrofoil control surfaces 134. Similarly, some examples of the rear hydrofoilassembly 110 include a rear hydrofoil 136, one or more rear hydrofoil struts 138 that couple the rear hydrofoil 136 to the hull 102, and one or more rear hydrofoil control surfaces 140.

[0136] Some examples of the main hydrofoil 130 and the rear hydrofoil 136 take the form of one or more hydrodynamic lifting surfaces (also referred to as “foils”) configured to be operated partially or entirely submerged underwater while the hull 102 of the craft 100 remains above and clear of the water’s surface. In operation, as the craft 100 moves through water with the main hydrofoil 130 and the rear hydrofoil 136 submerged, the hydrofoils generate a lifting force that causes the hull 102 to rise above the surface of the water. In general, the lifting force generated by the hydrofoils must be at least equal to the weight of the craft 100 to cause the hull 102 to rise above the surface of the water. The lifting force of the hydrofoils depends on the speed and angle of attack at which the hydrofoils move through the water, as well as their various physical dimensions, including the aspect ratio, the surface area, the span, and the chord of the foils.

[0137] The height at which the hull 102 is elevated above the surface of the water during hydrofoil-borne operation is limited by the length of the one or more main hydrofoil struts 132 that couple the main hydrofoil 130 to the hull 102 and the length of the one or more rear hydrofoil struts 138 that couple the rear hydrofoil 136 to the hull 102. In some examples, the main hydrofoil strut 132 and the rear hydrofoil strut 138 are long enough to lift the hull 102 at least five feet above the surface of the water during hydrofoil-borne operation, which facilitates operation in substantially choppy waters. Struts of other lengths may be used as well. For instance, in some examples, longer struts that allow for better wave-isolation of the hull 102 (but at the expense of the stability of the craft 100 and increasing complexity of the retraction system) are utilized.

[0138] In practice, hydrofoils have a limited top speed before cavitation occurs, which results in vapor bubbles forming and imploding on the surface of the hydrofoil. Cavitation not only may cause damage to a hydrofoil but also significantly reduces the amount of lift generated by the hydrofoil and increases drag. Therefore, it is desirable to reduce the onset of cavitation by designing the main hydrofoil 130 and the rear hydrofoil 136 in a way that allows the hydrofoils to operate at higher speeds (e.g., -20-45 mph) and across the entire required hydrofoil-borne speed envelope before cavitation occurs. For instance, in some examples, the onset of cavitation is controlled based on the geometric design of the main hydrofoil 130 and the rear hydrofoil 136. Additionally, in some examples, the structural design of the main hydrofoil 130 and the rear hydrofoil 136 is configured to allow the surfaces of the hydrofoils to flex and twist at higher speeds, which may reduce loading on the hydrofoils and delay the onset of cavitation.

[0139] Further, in some examples, the distributed blown-wing propulsion system described above further facilitates the delay of onset of cavitation on the main hydrofoil 130 and the rearhydrofoil 136. Cavitation is caused by both (i) the amount of lift generated by a hydrofoil and (ii) the profile of the hydrofoil (which is affected by both the hydrofoil’ s angle of attack and its vertical thickness) as it moves through water. Reducing the amount of lift generated by the hydrofoil delays the onset of cavitation. Because the blown-wing propulsion system creates additional lift on the main wing 104, the amount of lift exerted on the main hydrofoil 130 and the rear hydrofoil 136 to lift the hull 102 out of the water is reduced. Further, because the main hydrofoil 130 and the rear hydrofoil 136 do not need to generate as much lift to raise the hull 102 out of the water, their angles of attack may be reduced as well, which further delays the onset of cavitation. In some examples, combining the blown-wing propulsion system with the hydrofoil designs described herein facilitates operating the craft 100 in a hydrofoil -borne mode at speeds above 35 knots before cavitation occurs.

[0140] As noted above, some examples of the main hydrofoil assembly 108 and the rear hydrofoil assembly 110 include one or more main and rear hydrofoil control surfaces 134, 140, respectively. Some examples of the main hydrofoil control surfaces 134 include one or more hinged surfaces on a trailing or leading edge of the main hydrofoil 130 as well as one or more actuators which are operated by the control system of the craft 100 to rotate the hinged surfaces so that they extend above or below the main hydrofoil 130. Some examples of the main hydrofoil control surfaces 134 on the main hydrofoil 130 are operated in a similar manner as the flaps 118 and ailerons 120 on the main wing 104 of the craft 100. In some examples, lowering the control surfaces 134 to extend below the main hydrofoil 130 changes the hydrodynamic shape of the main hydrofoil 130 in a manner that generates additional lift on the main hydrofoil 130, similar to the aerodynamic effect of lowering the flaps 118. In some examples, asymmetrically raising one or more of the control surfaces 134 (e.g., raising a control surface 134 on only one side of the main hydrofoil 130) changes the hydrodynamic shape of the main hydrofoil 130 in a manner that generates a roll force on the main hydrofoil 130, similar to the aerodynamic effect of raising one of the ailerons 120.

[0141] Likewise, some examples of the rear hydrofoil control surfaces 140 include one or more hinged surfaces on a trailing or leading edge of the rear hydrofoil 136 as well as one or more actuators, which are operated by the control system of the craft 100 to rotate the hinged surfaces so that they extend above or below the rear hydrofoil 136. In some examples, the rear hydrofoil control surfaces 140 on the rear hydrofoil 136 are operated in a similar manner as the elevators 126 on the tail 106 of the craft 100. In some examples, lowering the control surfaces 140 to extend below the rear hydrofoil 136 changes the hydrodynamic shape of the rear hydrofoil 136 in a manner that causes the craft 100 to pitch downwards, similar to the aerodynamic effect of loweringthe elevators 126. In some examples, raising the control surfaces 140 to extend above the rear hydrofoil 136 changes a hydrodynamic shape of the rear hydrofoil 136 in a manner that causes the craft 100 to pitch upwards, similar to the aerodynamic effect of raising the elevators 126.

[0142] In some examples, one or both of the main hydrofoil control surfaces 134 or the rear hydrofoil control surfaces 140 include rudder-like control surfaces similar to the rudder 128 on the tail 106 of the craft 100. For instance, some examples of the main hydrofoil control surfaces 134 include one or more hinged surfaces on a trailing edge of the main hydrofoil strut 132 as well as one or more actuators, which are operated by the control system of the craft 100 to rotate the hinged surfaces so that they extend to the left or right of the main hydrofoil strut 132. Similarly, some examples of the rear hydrofoil control surfaces 140 include one or more hinged surfaces on a trailing edge of the rear hydrofoil strut 138 as well as one or more actuators, which are operated by the control system of the craft 100 in order to rotate the hinged surfaces so that they extend to the left or right of the rear hydrofoil strut 138. In some examples, actuating the main hydrofoil control surfaces 134 or the rear hydrofoil control surfaces 140 in this manner changes the hydrodynamic shape of the main hydrofoil strut 132 or the rear hydrofoil strut 138, respectively, which facilitates controlling the yaw of the craft 100 when operating in a waterborne or hydrofoil- borne mode, similar to the effect of actuating the rudder 128 of the craft 100, as described above.

[0143] In some examples, instead of (or in addition to) actuating hinged control surfaces on the main hydrofoil 130 and / or the rear hydrofoil 136, a control system of the craft 100 actuates the entire main hydrofoil 130 and / or the entire rear hydrofoil 136 themselves. In some examples, the craft 100 includes one or more actuators for rotating the main hydrofoil 130 and / or the rear hydrofoil 136 around the yaw axis. In some examples, the craft 100 includes one or more actuators for controlling the angle of attack of the main hydrofoil 130 and / or the rear hydrofoil 136 (i.e., rotating the main hydrofoil 130 and / or the rear hydrofoil 136 around the pitch axis). Some examples of the craft 100 include one or more actuators for rotating the main hydrofoil 130 and / or the rear hydrofoil 136 around the roll axis. Some examples of the craft 100 include one or more actuators for changing a camber or shape of the main hydrofoil 130 and / or the rear hydrofoil 136. Some examples of the craft 100 include one or more actuators for flapping the main hydrofoil 130 and / or the rear hydrofoil 136 to help propel the craft 100 forward or backward. Other examples are possible as well.

[0144] Further, some examples of the craft 100 dynamically control an extent to which the main hydrofoil 130 and / or the rear hydrofoil 136 are deployed based on an operational mode (e.g., hull-borne, hydrofoil-borne, or wing-borne modes) of the craft 100. For instance, in some examples, during hull-borne mode, the rear hydrofoil assembly 110 is partially deployed orretracted to increase turning authority. The amount of partial deployment or retraction may be a function of the desired overall vehicle draft when operating in a shallow water environment. In some examples, during hydrofoil-borne mode, the main hydrofoil assembly 108 is partially retracted to reduce the distance between the hull of the vehicle and the water’s surface. This increases the amount of lift generated by the main wing 104 by operating the wing closer to the surface of the water, increasing the effects of the aerodynamic ground effect.

[0145] As noted above, some examples of the main hydrofoil assembly 108 and rear hydrofoil assembly 110 interface with a deployment system that facilitates retracting the respective hydrofoil assemblies 108, 110 into or toward the hull 102 for hull-borne or wing-borne operation and for extending the respective hydrofoil assemblies 108, 110 below the hull 102 for hydrofoil- borne operation. As described further below, in some embodiments, the deployment system is used in connection with extending, retracting, and / or otherwise controlling the positioning of the hydrofoil assemblies 108, 110 during takeoff when the craft is transitioning from hydrofoil-borne operation to wing-borne operation.E. Hydrofoil Deployment Systems

[0146] Figure 2 illustrates an example of a main hydrofoil deployment system 200 that facilitates retracting and extending of the main hydrofoil assembly 108. As shown, some examples of the main hydrofoil deployment system 200 take the form of a linear actuator that includes one or more brackets 202 that couple the main hydrofoil assembly 108 (by way of the main hydrofoil strut 132) to one or more vertical tracks 204. Some examples of the brackets 202 are configured to move vertically along the tracks 204, such that when the brackets 202 move vertically along the tracks 204, the main hydrofoil assembly 108 likewise moves vertically. Some examples of the brackets 202 are coupled to a leadscrew 206 that, when rotated, causes vertical movement of the brackets 202. Some examples of the leadscrew 206 are rotatable by any of various sources of torque, such as an electric motor coupled to the leadscrew 206 by a gear assembly.

[0147] Some examples of the main hydrofoil deployment system 200 further include one or more sensors 210 configured to detect a vertical position of the main hydrofoil assembly 108. For example, a first sensor senses when the main hydrofoil assembly 108 has reached a fully retracted position and a second sensor senses when the main hydrofoil assembly 108 has reached a fully extended position. However, the main hydrofoil deployment system 200 may include additional sensors for detecting additional discrete positions or continuous positions of the main hydrofoil assembly 108. Some examples of the sensors are included as part of, or otherwise configured to communicate with, the control system of the craft 100 to provide the control system with data that indicates the position of the main hydrofoil assembly 108. Some examples of the control systemuse this data to determine whether to operate the electric motor to retract or extend the main hydrofoil assembly 108.

[0148] In some examples, such as examples where the linear actuator is not a self-locking linear actuator, the main hydrofoil deployment system 200 includes a locking or braking mechanism for holding the main hydrofoil strut 132 in a fixed position (e.g., in a fully retracted or fully extended position). An example of the locking mechanism corresponded to a dual-action mechanical brake that is coupled to the electric motor, the leadscrew 206, or the gear assembly.

[0149] While the above description provides various details of an example main hydrofoil deployment system 200, it should be understood that the main hydrofoil deployment system 200 illustrated in Figure 2 is for illustrative purposes and is not meant to be limiting. For instance, the main hydrofoil deployment system 200 may include any of various linear actuators now known or later developed that are capable of retracting and extending the main hydrofoil assembly 108.

[0150] Figure 3 illustrates an example of a rear hydrofoil deployment system 300 that facilitates retracting and extending the rear hydrofoil assembly 110. As shown, some examples of the rear hydrofoil deployment system 300 include an actuator 305 to the rear hydrofoil strut 138. When actuated, the actuator 305 causes the rear hydrofoil strut 138 to raise or lower by causing the rear hydrofoil strut 138 to slide vertically along a shaft 307. While not illustrated in Figure 3, in some examples, the rudder 128 is mounted to the shaft 307 such that, when the actuator 305 raises the rear hydrofoil strut 138, the rear hydrofoil strut 138 retracts at least partially into the rudder 128. Additionally, some examples of the rear hydrofoil deployment system 300 include one or more servo motors configured to rotate the rear hydrofoil strut 138 around the shaft. In this respect, in some examples, the rear hydrofoil strut 138 is rotated around the shaft to act as a hydrorudder when submerged in water or to act as an aero-rudder when out of the water. Further, because the rudder 128 is mounted to the same shaft 307 as the rear hydrofoil strut 138 and the rear hydrofoil strut 138 can be retracted into the rudder 128, the same servo motor can also be used to control the rotation of the rudder 128.

[0151] The actuator 305 of the rear hydrofoil deployment system 300 may take various forms and may, for instance, include any of various linear actuators now known or later developed that are capable of retracting and extending the rear hydrofoil assembly 110. Further, in some examples, the actuator 305 has a non-unitary actuation ratio such that a given movement of the actuator 305 causes a larger corresponding induced movement of the rear hydrofoil assembly 110. This can help allow for faster retractions of the rear hydrofoil assembly 110, which may be beneficial during takeoff.

[0152] Some examples of the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 are configured such that, when fully retracted, the hydrofoil assembly is flush, conformal, or tangent to the hull 102. For instance, some examples of the hull 102 include one or more recesses configured to receive the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110. In this regard, some examples of the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 have a shape such that when the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 are fully retracted into the recesses of the hull 102, the outer contour of the hull 102 forms a substantially smooth transition at the intersection of the hull 102 and the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110.

[0153] Other examples of the main hydrofoil assembly 108 and / or the rear hydrofoil protrude slightly below the hull 102 when retracted. These examples of the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 are configured to have a non-negligible effect on the aerodynamics of the craft 100. Some examples of the craft 100 are configured to leverage these effects to provide additional control of the craft 100. For instance, in some examples, when the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 are retracted but still exposed, the exposed hydrofoil is manipulated in flight to impart forces and moments on the craft 100 similar to an aero-control surface.

[0154] Some examples of the hydrofoil assemblies 108, 110 disclosed herein are mounted on a pivot that is locked underwater but is unlocked to allow the hydrofoil to move around the pivot in the air. At that point, the control surfaces act like trim tabs and are able to effect movement of the entire unlocked, pivoting hydrofoil, which would otherwise require impractically large and heavy servo motors. This configuration facilitates unlocking and moving of the hydrofoil using a slow servo and / or a combination of control surface movement combined with forward movement through water, and then re-locked such that the hydrofoil is at a selected angle of incidence.

[0155] As noted above, some examples of the main hydrofoil assembly 108 are configured to be retractable. Some examples of the hull 102 include openings through which the strut 132 of the main hydrofoil assembly 108 are retracted and extended. Some examples of the hull 102 are configured to isolate water that enters through these openings (e.g., when the hull 102 contacts the water surface) and to allow for the water to drain from the hull 102 after the hull 102 is lifted out of the water. For instance, some examples of the hull 102 include pockets 142 on each side of the hull 102 aligned above the strut 132. Some examples of the pockets 142 are isolated from the remainder of the interior of the hull 102 so that water that accumulates in the pockets 142 does not reach any undesired areas (e.g., the cockpit, passenger seating area, areas that house the battery system 400, components of the control system of the craft 100, etc.). Further, some examples ofthe pockets 142 include venting holes or other openings located at or near the bottom of the pockets 142. The venting openings are configured to allow water that enters the pockets 142 to vent out of the pockets 142 when the hull 102 is lifted out of the water.

[0156] Some examples of the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 include one or more propellers for additional propulsion when submerged underwater. For instance, in some examples, one or more propellers are mounted to the main hydrofoil 130 and / or the rear hydrofoil 136. In some examples, the propellers are configured to provide additional propulsion force to the craft 100 during hydrofoil-borne or hull-borne operation.

[0157] In some examples, propellers are mounted to the hull 102. The propellers are submerged during hull-borne operation. In some examples, the propellers are configured to provide additional propulsion force to the craft 100 during hull-borne operation.

[0158] Some examples of the main and / or rear hydrofoil assemblies 108, 110 include various failsafe mechanisms in case of malfunction. For instance, in some examples, when one or both of the main and rear hydrofoil deployment systems 200, 300 cannot be retracted due to a malfunction, the craft 100 is configured to jettison the malfunctioning assembly. In this regard, some examples of the main and / or rear hydrofoil assemblies 108, 110 are coupled to the hull 102 by a releasable latch. Some examples of the control system of the craft 100 are configured to identify a retraction malfunction (e.g., based on data received from the positional sensors 210) and responsively open the latch to release the connection between the hull 102 and the malfunctioning hydrofoil assembly. In some examples, the weight of the malfunctioning hydrofoil assembly is sufficient to jettison the malfunctioning hydrofoil assembly out of the hull 102 when the latch is opened. Some examples of the craft 100 include an actuator or some other mechanism to jettison the malfunctioning hydrofoil assembly out of the hull 102. In some examples, the main and / or rear hydrofoil assemblies 108, 110 are configured to break in a controlled manner upon impact with water. For instance, in some examples, a joint between the main hydrofoil strut 132 and the hull 102 and / or a joint between the rear hydrofoil strut 138 and the hull 102 is configured to disconnect when subjected to a torque significantly larger than standard operational torques at the joints. Other designs for providing controlled breaks are possible as well.F. Battery system

[0159] Figure 4 illustrates an example of an onboard battery system. In some examples, the battery system 400 is arranged in a protected area 402 of the hull 102 below a passenger seating area 404. Some examples of the battery system 400 are separated from the passenger seating area 404 by a firewall 406 to protect the passengers from harm if a thermal runaway occurs. In this regard, some examples of the craft 100 include a battery management system comprising voltage,current, and / or thermal sensors for detecting thermal runaway or some other fire detection system for detecting a fire in the protected area 402.

[0160] Some examples of the craft 100 include one or more mechanisms for flooding the battery system 400 (e.g., with an inert gas fire, with water, etc.) upon detecting a thermal runaway or a fire in the protected area 402. For instance, some examples of the hull 102 comprise one or more valves or other controllable openings. The control system of the craft 100 is configured to open the valves and / or controllable openings upon detecting a fire in the protected area 402 or thermal runaway in the battery system 400 to allow water to enter the protected area 402 and to extinguish or prevent a fire in the protected area 402.

[0161] In some examples, the battery system 400 is configured to be jettisoned through one or more of the controllable openings in the hull 102 described above. In this regard, in some examples, the weight of the battery system 400 is sufficient to jettison the battery system 400 out of the hull 102 when the hull 102 is opened. In some examples, the craft 100 comprises an actuator or the like configured to jettison the battery system 400 out of the hull 102.

[0162] In other examples, the craft 100 may take measures to become waterborne in response to detecting a fire in the protected area 402 or thermal runaway in the battery system 400. Some examples of the control system of the craft 100 determine a fire suppression operation to perform based on the operational state of the craft 100 (e.g., operating in hull-borne, hydrofoil-borne, or wing-borne mode). For instance, when operating in hull-borne mode and upon detecting a thermal runaway or a fire in the protected area 402, some examples of the control system are configured to flood the battery system 400 as described above. When operating in hydrofoil-borne or a wing- borne mode, the control system is configured to cause the craft 100 to transition to hull-borne mode upon detecting a thermal runaway or a fire in the protected area 402 and then flood the battery system 400. Battery system 400 is described in further detail below.G. Control System

[0163] Figure 5 illustrates an example of a control system 500 of the craft 100. As shown, some examples of control system 500 include one or more processors 502, data storage 504, a communication interface 506, a propulsion system 508, actuators 510, a Global Navigation Satellite System (GNSS) 512, an inertial navigation system (INS) 514, a radar system 516, a lidar system 518, an imaging system 520, various sensors 522, a flight instrument system 524, and flight controls 526. In some examples, some or all of these components communicate with one another via one or more communication links 528 (e.g., a system bus, a public, private, or hybrid cloud communication network, etc.)

[0164] Some examples of processors 502 correspond to or comprise general-purpose processors (e.g., a single- or multi-core microprocessor), special-purpose processors (e.g., an application-specific integrated circuit or digital-signal processor), programmable logic devices (e.g., a field-programmable gate array), controllers (e.g., microcontrollers), and / or any other processor components now known or later developed. Further, while the one or more processors 502 are illustrated as a separate stand-alone component of the control system 500, it should also be understood that the one or more processors 502 could comprise processing components that are distributed across one or more of the other components of the control system 500.

[0165] Some examples of the data storage 504 comprise one or more non-transitory computer- readable storage mediums that are collectively configured to store (i) program instructions executable by the one or more processors 502 such that the control system 500 is configured to perform some or all of the functions disclosed herein, and (ii) data that may be received, derived, or otherwise stored, for example, in one or more databases, file systems, or the like, by the control system 500 in connection with the functions disclosed herein. In this respect, the one or more non- transitory computer-readable storage mediums of data storage 504 may take various forms, examples of which may include volatile storage mediums such as random-access memory, registers, cache, etc. and non-volatile storage mediums such as read-only memory, a hard-disk drive, a solid-state drive, flash memory, an optical -storage device, etc. Further, while the data storage 504 is illustrated as a separate stand-alone component of the control system 500, it should also be understood that the data storage 504 may comprise computer-readable storage mediums that are distributed across one or more of the other components of the control system 500.

[0166] Some examples of the communication interface 506 include one or more wireless interfaces and / or one or more wireline interfaces, which allow the control system 500 to communicate via one or more networks. Some example wireless interfaces provide for communication under one or more wireless communication protocols, such as Bluetooth, WiFi (e.g., an IEEE 802.11 protocol), Long-Term Evolution (LTE), WiMAX (e.g., an IEEE 802.16 standard), a radio-frequency ID (RFID) protocol, near-field communication (NFC), and / or other wireless communication protocols. Some example wireline interfaces include an Ethernet interface, a Universal Serial Bus (USB) interface, CAN Bus, RS-485, or similar interface to communicate via a wire, a twisted pair of wires, a coaxial cable, an optical link, a fiber-optic link, or other physical connection to a wireline network.

[0167] Some examples of the propulsion system 508 include one or more electronic speed controllers (ESCs) for controlling the electric motor propeller assemblies 116 distributed across the main wing 104 and, in some examples, across the horizontal stabilizer 124. Some examples ofthe propulsion system 508 include a separate ESC for each respective propeller assembly 116, such that the control system 500 individually controls the rotational speeds of the electric motor propeller assemblies 116.

[0168] Some examples of the actuators 510 include any of the actuators described herein, including (i) actuators for raising and lowering the flaps 118, ailerons 120, elevators 126, main hydrofoil control surfaces 134, and rear hydrofoil control surfaces 140, (ii) actuators for turning the rudder 128, the main hydrofoil control surfaces 134 positioned on the main hydrofoil strut 132, and the rear hydrofoil control surfaces 140 positioned on the rear hydrofoil strut 138, (iii) actuators for retracting and extending the main hydrofoil assembly 108 and the rear hydrofoil assembly 110, and / or (iv) actuators for performing the various other disclosed actuations of the main hydrofoil assembly 108 and the rear hydrofoil assembly 110. Each of the actuators described herein may include any actuators now known or later developed capable of performing the disclosed actuation. Some examples of the actuators correspond to linear actuators, rotary actuators, hydraulic actuators, pneumatic actuators, electric actuators, electro-hydraulic actuators, and mechanical actuators. Some examples of the actuators correspond to electric motors, stepper motors, and hydraulic cylinders. Other examples are contemplated herein as well.

[0169] Some examples of the GNSS system 512 are configured to provide a measurement of the location, speed, altitude, and heading of the craft 100. The GNSS system 512 includes one or more radio antennas paired with signal processing equipment. Data from the GNSS system 512 may allow the control system 500 to estimate the position and speed of the craft 100 in a global reference frame, which can be used for route planning, operational envelope protection, and vehicle traffic deconfliction by both understanding where the craft 100 is located and comparing the location with known traffic.

[0170] Some examples of the INS 514 include motion sensors, such as angular and / or linear accelerometers, and rotational sensors, such as gyroscopes, to calculate the position, orientation, and speed of the craft 100 using dead reckoning techniques. In some examples, one or more of these components are used by the control system to calculate actuator outputs to stabilize or otherwise control the vehicle during all modes of operation.

[0171] Some examples of the radar system 516 include a transmitter and a receiver. The transmitter may transmit radio waves via a transmitting antenna. The radio waves reflect off an object and return to the receiver. The receiver receives the reflected radio waves via a receiving antenna, which may be the same antenna as the transmitting antenna, and the radar system 516 processes the received radio waves to determine information about the object’s location and speedrelative to the craft 100. This radar system 516 may be utilized to detect, for example, the water surface, maritime or wing-borne vehicle traffic, wildlife, or weather.

[0172] Some examples of the lidar system 518 comprise a light source and an optical receiver. The light source emits a laser that reflects off an object and returns to the optical receiver. The lidar system 518 measures the time for the reflected light to return to the receiver to determine the distance between the craft 100 and the object. This lidar system 518 may be utilized by the flight control system to measure the distance from the craft 100 to the surface of the water in various spatial measurements.

[0173] Some examples of the imaging system 520 include one or more still and / or video cameras configured to capture image data from the environment of the craft 100. Some examples of the cameras correspond to or comprise charge-coupled device (CCD) cameras, complementary metal-oxide-semiconductor (CMOS) cameras, short-wave infrared (SWIR) cameras, mid-wave infrared (MWIR) cameras, or long-wave infrared (LWIR) cameras. Some examples of the imaging system 520 are configured to perform obstacle avoidance, localization techniques, water surface tracking for more accurate navigation (e.g., by applying optical flow techniques to images), video feedback, and / or image recognition and processing among other possibilities.

[0174] As noted above, some examples of the control system 500 include various other sensors 522 for use in controlling the craft 100. Examples of such sensors 522 correspond to or comprise thermal sensors or other fire detection sensors for detecting a fire in the hull 102 or for detecting thermal runaway in the battery system 400. As further described above, the sensors 522 may include position sensors for sensing the position of the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 (e.g., sensing whether the assemblies are in a retracted or extended position). Examples of position sensors may include photodiode sensors, capacitive displacement sensors, eddy-current sensors, Hall effect sensors, inductive sensors, or any other position sensors now known or later developed.

[0175] Some examples of the sensors 522 facilitate determining the altitude of the craft 100. For instance, some examples of the sensor 522 include an ultrasonic altimeter configured to emit and receive ultrasonic waves. The emitted ultrasonic waves reflect off the water surface below the craft 100 and return to the altimeter. The ultrasonic altimeter measures the time for the reflected ultrasonic wave to return to the altimeter to determine the distance between the craft 100 and the water surface. Some examples of the sensor 522 include a barometer for use as a pressure altimeter. The barometer measures the atmospheric pressure in the environment of the craft 100 and determines the altitude of the craft 100 based on the measured pressure. Some examples of the sensor 522 include a radar altimeter to emit and receive radio waves. The radar altimetermeasures the time for the radio wave to reflect off of the surface of the water below the craft 100 to determine a distance between the craft 100 and the water surface. In some examples, these sensors are placed in different locations on the craft 100 to reduce the impact of sensor constraints, such as sensor deadband or sensitivity to splashing water.

[0176] Some examples of the control system 500 are configured to use one or more of the sensors 522 or other components of the control system 500 to help navigate the craft 100 through maritime traffic or to avoid any other type of obstacle. For example, some examples of the control system 500 determine the position, orientation, and speed of the craft 100 based on data from the INS 514 and / or the GNSS 512, and the control system 500 may determine the location of an obstacle, such as a maritime vessel, a dock, or various other obstacles, based on data from the radar system 516, the lidar system 518, and / or the imaging system 520. Some examples of the control system 500 determine the location of an obstacle using the Automatic Identification System (AIS). Some examples of the control system 500 are configured to maneuver the craft 100 to avoid collision with an obstacle based on the determined position, orientation, and speed of the craft 100 and the determined location of the obstacle by actuating various control surfaces of the craft 100 in any of the manners described herein.

[0177] Some examples of the flight instrument system 524 include instruments for providing data about the altitude, speed, heading, orientation (e.g., yaw, pitch, and roll), battery levels, or any other information provided by the various other components of the control system 500.

[0178] Some examples of the flight controls 526 include one or more joysticks, thrust control levers, buttons, switches, dials, levers, or touch screen displays, etc. In operation, a pilot may use the flight controls 526 to operate one or more control surfaces (e.g., flaps, ailerons, elevators, rudder, propulsion propellers, etc.) of the craft 100 to thereby maneuver the craft 100 (e.g., control the direction, speed, altitude, etc., of the craft 100)

[0179] In some examples, the combinations of control surfaces on the craft 100 used by the control system 500 to control operations of the craft 100 depends on the mode of operation of the craft 100 and is determined based at least in part on aspects such as vehicle position, speed, attitude, acceleration, rotational rates, and / or altitude above water. Table 1 summarizes an example of the relationship between the control surfaces and the operation mode.Table 1

[0180] In some examples, the propulsion control surfaces in the table include the propeller assembly 116, as well as any propellers mounted to the hull 102, main hydrofoil assembly 108, or rear hydrofoil assembly 110. In some examples, the aerodynamic elevator control surfaces include elevator 126, the aerodynamic ailerons include ailerons 120, the aerodynamic rudder includes rudder 128 (when not submerged), the aerodynamic flaps include flaps 118, the hydrodynamic elevator includes rear hydrofoil control surfaces 140, the hydrodynamic flaps include main hydrofoil control surfaces 134, and the hydrodynamic rudder includes rudder 128 (when submerged).

[0181] In some examples, when actuating the control surfaces in the various examples, operational modes identified in Table 1 above, the control system 500 executes different levels of stabilization along the various vehicle axes during different modes of operation. Table 2-1 and Table 2-2 below identify alternative examples of stabilization controls that the control system 500 applies during the various modes of operation for each axis of the craft 100. Closed-loop control may comprise feedback and / or feed-forward control.Table 2-1Table 2-2

[0182] Further, in some examples, the control system 500 is configured to actuate different control surfaces to control the movement of the craft 100 about its different axes. Table 3 below identifies example axial motions that are affected by the various control surfaces of the craft 100.III. Example Modes of OperationA. Hull-Borne Operation

[0183] Figure 6A illustrates an example of the craft 100 when the craft 100 is operating in a hull-borne mode. During this mode, the craft 100 is docked and floating on the hull 102, with the buoyancy of the outriggers 114 providing for roll stabilization of the craft 100. While docked, the battery system 400 of the craft 100 may be charged. In some examples, rapid charging is aided by an open or closed-loop water-based cooling system. In some examples, the surrounding body of water is used in the loop or as a heat sink. In some examples, the craft 100 includes a heat sink integrated into the hull 102 for exchanging heat from the battery system 400 to the surrounding body of water. In other examples, the heat sink is located offboard in order to reduce the mass of the craft 100.

[0184] Additionally, in some examples, the propeller assemblies 116 are folded in a direction away from the dock while the craft 100 is docked to help avoid collision with nearby structures or people. This folding may be actuated in various ways, such as by metal spring force, hydraulic pressure, electromechanical actuation, or centrifugal force due to propeller rotation. Other examples are possible as well. Further, in some examples, the main hydrofoil assembly 108 andthe rear hydrofoil assembly 110 are retracted (or partially retracted) to avoid collisions with nearby underwater structures.

[0185] In some examples, when the craft 100 is ready to depart, the craft 100 uses its propulsion systems, including the propeller assemblies 116 and / or the underwater propulsion system (e.g., one or more outrigger propulsion systems, one or more propeller pods mounted to the hull 102, the main hydrofoil assembly 108, and / or the rear hydrofoil assembly 110), to maneuver away from the dock while remaining hull-borne. In some examples, the main hydrofoil assembly 108 and the rear hydrofoil assembly 110 remain retracted (or partially retracted) during this maneuvering to reduce the risk of hitting underwater obstacles near docks or in shallow waterways. However, when there is a limited risk of hitting underwater obstacles, the craft 100 may partially or fully extend the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110. With the main hydrofoil assembly 108 and / or the rear hydrofoil assembly 110 extended, the craft 100 actuates the main hydrofoil control surfaces 134 and / or the rear hydrofoil control surfaces 140 to improve maneuverability as described above.

[0186] In some examples, at low speeds during hull-borne operation, the control system 500 controls the position and / or rotation of the craft 100 by causing all of the propeller assemblies 116 to spin at the same idle speed, but with a first subset spinning in a forward direction and a second subset spinning in a reverse direction. For instance, in some examples, the control system 500 causes propeller assemblies 116a, 116c, 116e, 116h, 116j, and 1161 to idle in reverse and propeller assemblies 116b, 116d, 116f, 116g, 116i, and 116k to idle forward. In this arrangement, the control system 500 causes the craft 100 to make various maneuvers without having to change the direction of rotation of any of the propeller assemblies 116. For instance, to induce a yaw on the craft 100, in some examples, the control system 500 increases the speed of the reverse propeller assemblies on one side of the main wing 104 while increasing the speed of the forward propeller assemblies on the other side of the main wing 104 and without causing any of the propeller assemblies to transition from forward to reverse or from reverse to forward. For example, idling the propellers at a nominal RPM may allow for a faster response in generating a yaw moment on the craft 100 because the propellers required for generating the yaw moment do not have to increase from zero RPM to the desired RPM value. They can spin from the idle RPM to the desired RPM value.B. Foil-borne Maneuvering Operation

[0187] Figure 6B illustrates an example of the craft 100 when the craft 100 is operating in hydrofoil-borne maneuvering mode. During this mode, the craft 100 is configured to, for example, move through harbors and crowded waterways at speeds generally between 20-45 mph. In this regard, the craft 100 may extend the main hydrofoil assembly 108 and the rear hydrofoil assembly110 (if not already extended) and accelerate using the previously described propulsion system towards a desired takeoff speed. During acceleration, the craft 100 reaches a speed at which the main hydrofoil assembly 108 and the rear hydrofoil assembly 110 alone support the weight of the craft 100, and the hull 102 is lifted above the surface of the water (e.g., by 3-5 ft) so that the hull is clear of any surface waves. After the hull 102 leaves the surface of the water, the drag forces exerted on the craft 100 drop significantly, and the amount of thrust required to maintain acceleration can be reduced. Therefore, in some examples, after the hull 102 has left the water, the control system 500 reduces the speed of the propeller assemblies 116 to lower the thrust of the craft 100.

[0188] Some examples of the control system 500 sustain this operational mode by actively controlling the pitch and speed of the craft 100 so that the main hydrofoil assembly 108 and the rear hydrofoil assembly 110 continue to entirely support the weight of the craft 100. In this regard, some examples of the control system 500 actuate the main hydrofoil control surfaces 134 and / or the rear hydrofoil control surfaces 140 and / or the propulsion system to stabilize the attitude of the craft 100 to maintain the desired height above the surface of the water, vehicle heading, and vehicle forward speed. In this regard, some examples of the control system 500 are configured to detect various changes in the yaw, pitch, or roll of the craft 100 based on data provided by the INS 514 and to make calculated actuations of the main hydrofoil control surfaces 134 and / or the rear hydrofoil control surfaces 140 to counteract the detected changes.C. Foil-borne Takeoff Operation

[0189] Figure 7A illustrates an example of the craft 100 when the craft 100 is operating in hydrofoil-borne takeoff mode. During this mode, the craft 100 is configured to, for example, move through open waters and obtain speeds generally between 40-50 mph to facilitate generating the lift required to become wing-borne.

[0190] Referring to Figure 7A, aero lift, LW, generally represents the lift generated by the main wing 104 of the craft 100 but can also include the lift generated by other surfaces such as the tail wing, hull, or propulsive devices such as propellers, rotors, jets, etc. LF generally corresponds to the lift generated by one or more hydrofoils 130, 136 of the craft 100, where LFF corresponds to the lift generated by the front foil and the LFR corresponds to the lift generated by the rear foil. WCRAFT corresponds to the force of gravity exerted on the craft 100 and is also referred to as the weight of the craft. During steady state operation, WCRAFT generally corresponds to LW+LFR+LFF which also corresponds to LNET. Throughout the description, the term LF is generally understood to correspond to LFR+LFF.

[0191] Some experimental craft developed by Applicant that include aero foils were unable to achieve the lift required to sustain flight. In these experimental craft, in an attempt to become airborne, the craft 100 would ramp up to a speed at which point the hydrofoil would breach the surface of the water, as WCRAFT < Lw + LF, and LF > 0, resulting in Lw < WCRAFT. However, in order to takeoff from the water’ s surface, the aero lift must be greater than or equal to the weight of the craft, however prior to takeoff, the hydrofoils are still under the water’s surface, and up until takeoff, have been generating lift (LF>0) as the aerodynamic lift has been insufficient for takeoff up until this point. If the hydro lift and the aero lift sum to greater than the weight of the craft, the vehicle will accelerate upwards and potentially create a premature takeoff condition (prior to condition CO in Figure 7B) as the aero lift, LW, generated by the wings, etc., of the craft 100 would be insufficient to sustain flight, and, as a result, the craft 100 would come back down and breach the water, ultimately preventing takeoff. The techniques disclosed below ameliorate these problems by controlling the hydrofoil lift vector, LF, specifically by generating downward forces of one or more hydrofoils 130, 136 of the craft 100 to keep the hydrofoils 130, 136 submerged until after the upwards aero lift, LW, is sufficient to allow the craft 100 to sustain flight.

[0192] In some examples, the lift LF is in the downward direction, and is introduced via the hydrofoil(s) as LW increases beyond WCRAFT while the craft 100 is increasing in speed in anticipation of takeoff. This allows the craft 100 to generate a greater overall aero lift, LW, prior to actual takeoff than would otherwise be possible. Then, at the appropriate time (e.g., when LW reaches some predetermined threshold such as the weight of the craft 100 or some margin thereof), the negative lift, LF, can be “released” from the craft 100, and the craft 100 can, as a result, proceed to become wing-borne.

[0193] Figure 7B is an example of a graph 700 that relates these aspects. The relationships shown in the graph 700 and the ways in which various lift forces, thresholds, etc., are depicted are merely examples and are provided to aid understanding of the various operations and procedures described herein. As shown, the net lift, LNET, on the craft 100 initially corresponds to the combination of the aero lift, LW, generated by the wing (e.g., main wing, tail wing, etc.) and the lift, LF, generated by the hydrofoils 130, 136 (e.g., LNET=LW + LF). On the left side of the graph 700, the speed of the craft 100 is such that LNET is sufficient to allow the craft 100 to operate in hydrofoil-borne maneuvering mode but is insufficient to allow the craft 100 to become wing- borne. Moving to the right of the graph 700 as speed increases, LW increases with increased craft 100 water speed. To maintain ride height and prevent the hydrofoils 130, 136 from breaching the water surface, LF is reduced in proportion to an increase in LW. For example, LF is adjusted with the speed of the craft 100 to maintain LNET at a margin equal to the weight, WCRAFT, of thecraft 100, or small deviations about equal to control ride height. The overall lift provided by the hydrofoils 130, 136 may decrease at the same rate at which lift from the wing is increased towards zero or even become negative with increased speed. For example, just before the speed of the craft 100 reaches the speed associated with condition CO, LF may be reduced to zero. The conditions at CO (e.g., speed of the craft 100, angle of attack of craft 100, deflection angles of control surfaces, angle of incidence of hydrofoils, etc.) may be such that LF may be zero or close to zero. At CO, the aero lift, LW, generated by the main wing 104 may be expected to be able to transition the craft 100 to a wing-borne mode of operation if the downwards hydrofoil lift, LF, were to be removed as LW = WCRAFT. Accordingly, at some time and / or increased speed after this point (e.g., speed associated with condition Cl ) where LW > WCRAFT, LF may be gradually or abruptly removed / released. This, in turn, allows LNET to approximately equal to or greater than WCRAFT which allows the craft 100 to take off and become wing-borne.

[0194] While not shown in the graph, in some examples, LF is not removed / released as described. Rather, as the craft 100 continues to accelerate, the downwards hydrofoil lift, LF, increases to a maximum downwards amount (e.g., a predetermined maximum amount and / or a maximum amount achievable due to the limitations of the control capabilities of the hydrofoil). As the aero lift, LW, generated by the main wing 105 continues to increase past this maximum amount of downwards hydrofoil lift, LF, LNET increases in the upwards direction beyond WCRAFT and the craft 100 is pulled from the water. This, in turn transitions the craft 100 to a wing-borne mode of operation.D. Wing-Borne Operation

[0195] Figure 8 illustrates an example of the craft 100 after becoming wing borne. In some examples, once the transition from hydrofoil-borne operation to wing-borne operation is complete, the control system 500 causes the main hydrofoil deployment system 200 and the rear hydrofoil deployment system 300 to respectively retract the main hydrofoil assembly 108 and the rear hydrofoil assembly 110. In some examples, the control system 500 initiates this retraction as soon as the hydrofoil assemblies 108, 110 are clear of the water to reduce the chance of the hydrofoil assemblies 108, 110 reentering the water. The control system 500 may determine that the hydrofoil assemblies 108, 110 are clear of the water in various ways. For instance, in an example, the control system 500 makes such a determination based on a measured altitude of the craft 100 (e.g., based on data provided by the radar system 516, the lidar system 518, and / or the other sensors 522 described above for measuring an altitude of the craft 100). In another example, the sensors 522 may further include one or more conductivity sensors, temperature sensors, pressure sensors, strain gauge sensors, or load cell sensors arranged on the hydrofoil assemblies 108, 110, and thecontrol system 500 may determine that the hydrofoil assemblies 108, 110 are clear of the waterbased on data from these sensors.

[0196] Once the craft 100 is clear of the water, the control system 500 continues to accelerate the craft 100 to the desired cruise speed by controlling the speed of the propeller assemblies 116. In some examples, the control system 500 retracts the flap systems when the craft 100 has achieved sufficient airspeed to generate enough lift to sustain altitude without them and actuates various control surfaces of the craft 100 and / or applies differential thrust to the propeller assemblies 116 to perform any desired maneuvers, such as turning, climbing, or descending, and to provide efficient lift distribution. While in wing-borne mode, the craft 100 can fly both low over the water’s surface in ground-effect or above ground-effect depending on operational conditions and considerations.E. Return to Hull-Borne Operation

[0197] To facilitate transitioning from wing-borne to hull-borne mode of operation (See Figure 6A), the control system 500 determines that the hydrofoil assemblies 108, 110 are fully or partially retracted so that the craft 100 may safely land on its hull 102. In some examples, the control system 500 additionally determines and suggests the desired landing direction and / or location-based on observed, estimated, or expected water surface conditions (e.g., based on data from the radar system 516, the lidar system 518, the imaging system 520, or other sensors 522).

[0198] The control system 500 initiates deceleration of the craft 100, for instance, by reducing the speeds of the propeller assemblies 116 until the craft 100 reaches a desired landing airspeed. During the deceleration, the control system 500 may deploy the flaps 118 to increase lift at low airspeeds and / or to reduce the stall speed. Once the craft 100 reaches the desired landing airspeed (e.g., approximately 50 knots), the control system 500 reduces the descent rate (e.g., to be less than approximately 200 ft / min). As the craft 100 approaches the surface of the water (e.g., once the control system 500 determines that the craft 100 is within 5 feet of the water surface), the control system 500 further slows the descent rate to cushion the landing (e.g., to be less than approximately 50 ft / min). As the hull 102 of the craft 100 impacts the surface of the water, the control system 500 reduces thrust, and the craft 100 rapidly decelerates due to the presence of hydrodynamic drag, the reduction in forward thrust, and the reduction or elimination of blowing air over the wing which significantly reduces lift causing the vehicle to settle into the water. The hull 102 settles into the water as the speed is further reduced until the craft 100 is stationary.

[0199] In some examples, after the craft 100 is settled in the water, the craft 100 is transitioned back to hydrofoil-borne maneuvering mode (See Figure 6B) by extending the hydrofoil assemblies 108, 110 to transition from hull-borne operation to hydrofoil-borne operation in the same manneras described above. In some examples, the control system 500 then sustains the hydrofoil-borne mode at the fifth stage and maneuvers the craft 100 into port while keeping the hull 102 insulated from surface waves. The control system 500 then reduces the thrust generated by the propeller assemblies 116 to lower the speed of the craft 100 until the hull 102 settles into the water, thereby transitioning that craft back to hull-borne operation at the sixth stage. The control system 500 then retracts the hydrofoil assemblies 108, 110 and performs the hull-borne operations described above to maneuver the craft 100 into a dock for disembarking passengers or goods and recharging the battery system 400.IV. Example Battery System Having Sets of Batteries and Corresponding Sets of Motors

[0200] As discussed above, in one aspect, the present disclosure is directed towards a battery system for a craft. The battery system for the craft includes a plurality of sets of batteries, where each set of batteries is configured to provide power to a respective set of propeller motors, and where each respective set of propeller motors includes (i) one or more of the craft’s port-side- propeller motors and (ii) one or more of the craft’s starboard-side-propeller motors. Examples of the disclosed battery system are described with reference to Figures 1 A-E and 9-12.

[0201] In general, the battery system may be for a craft such as the craft 100. With reference to Figures 1 A-E and 4, the craft 100 includes a hull, one or more wings coupled to the hull, a plurality of propellers arranged on the one or more wings, a plurality of propeller motors, and a battery system. In the examples of Figures 1 A-E, the propellers and propeller motors are integrated in the propeller assemblies.

[0202] The one or more wings of the craft 100 include a port side of the one or more wings and a starboard side of the one or more wings. As used herein, (i) the port side refers to the left side of the craft when aboard and facing fore (front) and (ii) the starboard side refers to the right side of the craft when aboard and facing fore (front). Further, the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboard- si de propellers. Still further, the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port-side-propeller motor is associated with a respective port-side propeller and each starboard-side-propeller motor is associated with a respective starboard- si de propeller.

[0203] Figure 9A illustrates an example schematic of the battery system 400. The battery system 400 includes a plurality 901 of sets of batteries, where each set of batteries is configured to provide power to a respective set of propeller motors, and where each respective set of propeller motors includes (i) one or more of the craft’s port-side-propeller motors and (ii) one or more of the craft’sstarboard-side-propeller motors. In particular, the plurality 901 of sets of batteries includes: (i) a first set of batteries 902 configured to provide power to a first set of motors 904; (ii) a second set of batteries 912 configured to provide power to a second set of motors 914; (iii) a third set of batteries 922 configured to provide power to a third set of motors 924; and (ii) a fourth set of batteries 932 configured to provide power to a fourth set of motors 934.

[0204] First set of motors 904 includes motors 115d, 115i, and 1151, second set of motors 914 includes motors 115f, 115g, and 115k, third set of motors 924 includes motors 115b, 115e, and 115h, and fourth set of motors 934 includes motors 115a, 115c, and 115j. In this example, motors 115a-l are the motors for the propellers of propeller assemblies 116a-l (see Figure 1 A), propellers of propeller assemblies 116a-f are starboard- si de propellers and propellers of propeller assemblies 116g-l are port-side propellers. Thus, motors 115a-f correspond to motors for starboard side propellers, and motors 115g-l correspond to motors for port side propellers.

[0205] In some examples, the motors to be included within the sets of propeller motors are selected such that the craft is configured to maintain both lift and flight control when the craft 100 is operating in a mode in which one of the sets of batteries is offline. More particularly, the battery system 400 is configured such that (i) particular sets of motors are paired with different sets of batteries and (ii) even if the batteries in a set of batteries configured to provide power to a given set of propeller motors goes offline during operation of the craft and the given set of propeller motors ceases operation, the other propellers of the craft are able to maintain safe operation of the craft. The pairing of particular sets of motors with different sets of batteries thus helps to improve the reliability, performance, and redundancy of the craft 100.

[0206] In general, the sets of motors are selected such that, for each given set of motors, the other sets of motors are able to cover for the given set of motors even if the given set of motors were to go offline for one reason or another. More particularly, the arrangement along the wing of the motors in the sets of motors is such that, even if the given set of motors were to go offline, the other sets of motors may continue their normal operation and still be capable of maintaining safe operation (e.g., maintenance of lift and / or control authority) of the craft even when the given set of motors is offline for one reason or another. The other sets of motors may be able to cover for a given set of motors (even if the given set of motors were to go offline for one reason or another) in various ways. For instance, in some examples, for each respective propeller in a given set of propellers, a coverage area associated with air that is blown by that respective propeller overlaps at least in part with a coverage area of air that is blown by a propeller from a different set of propellers. In general, coverage areas of propellers overlap when more than one propeller blows over a given surface (e.g., the given surface is wide enough to be blown by two propellers).Within examples, coverage area of a propeller refers to an area on a wing through which at least some air output by the propeller (also referred to as the “wake” of a propeller) flows. By having overlapping coverage areas, even if all the propellers in the given set of propellers go offline, the craft 100 may still maintain adequate lift and control for flight. In an example, a given coverage area might include one or more control surfaces that are relevant to maintenance of lift and / or control authority of the craft, such as a flaperon, aileron, or other such control surface.

[0207] As a simplified, illustrative example of overlapping coverage areas, Figure 9B depicts example coverage areas of the propeller assemblies 116a-l (which include motors 115a-l depicted in Figure 9A). For each given set of motors / propeller assemblies, each propeller assembly in the given set has a coverage area that overlaps at least in part with a coverage area of a propeller assembly associated with a different set of batteries.

[0208] For purposes of illustration, such overlapping coverage is described with respect to set of motors 934 (which is associated with set of batteries 932). With respect to propeller assemblies 116a, 116c, and 116j, each of those propeller assemblies has a coverage area that overlaps at least in part with a coverage area of a propeller assembly associated with a different set of batteries. More particularly, coverage area 952a of propeller assembly 116a overlaps with coverage area 952b of propeller assembly 116b (which is associated with set of batteries 924). Further, coverage area 952c overlaps of propeller assembly 116c with (i) coverage area 952b of propeller assembly 116b (which is associated with set of motors 924) and (ii) coverage area 952d of propeller assembly 116d (which is associated with set of motors 904). Still further, coverage area 952j of propeller assembly 116j overlaps with (i) coverage area 952i of propeller assembly 116i (which is associated with set of motors 904) and (ii) coverage area 952k of propeller assembly 116k (which is associated with set of motors 914). Given these overlapping coverage areas, even if all of propeller assemblies 116a, 116c, and 116j were to go offline and thus not blow air over the portions to the wing they typically would, the other propeller assemblies having the overlapping coverage areas would still be blowing at least some air over at least part of those portions of the wing. Thus, the other propellers are able to compensate for the propeller assemblies 116a, 116c, and 116j, which in turn would allow the craft 100 to still maintain adequate lift and control for flight. The other sets of motors 904, 914, and 924 similarly have such overlapping coverage.

[0209] In addition to or alternative to ensuring that, for each respective propeller in a given set of propellers, a coverage area associated with air that is blown by that respective propeller overlaps at least in part with a coverage area of air that is blown by a propeller from a different set of propellers, the sets of motors may be selected so as to balance positioning along the wing of propellers that may go offline.

[0210] The particular sets of motors that are paired with different sets of batteries may depend on various factors, examples of which are discussed below.

[0211] In some examples, the particular sets of propeller motors that are paired with different sets of batteries are selected based on control surfaces on the wing(s) of the craft 100. In this regard, the craft 100 may include a plurality of control surfaces on the one or more wings 104, such as flaps 118 and ailerons 120 as shown in Figures 1 A-B. The sets of motors may be selected to ensure that each control surface on the one or more wings 104 (or at least a subset of the control surfaces on the one or more wings 104) are within coverage areas of propellers associated with different sets. More particularly, each of these control surfaces or at least a portion of the control surface may be positioned within both (i) a coverage area associated with a first propeller from a first respective set and (ii) coverage area of a second propeller associated with a second respective set.

[0212] Returning to Figure 9B, this figure provides a simplified, illustrative example of such control-surface position within coverage areas of propellers associated with different sets of propeller motors. As shown in Figure 9B, wing 104 includes control surfaces 118a-b and 120a-b. In this illustrative example, control surface 120a is within both coverage area 952a of propeller assembly 116a and coverage area 952b of propeller assembly 116b. Further, with reference to control surface 118a, (i) a portion of control surface 118a is within coverage area 952d of propeller assembly 116d, (ii) control surface 118a is entirely within coverage area 952e of propeller assembly 116e, and (iii) a portion of control surface 118a is within coverage area 952f of propeller assembly 116f. Still further, with reference to control surface 118b, (i) a portion of control surface 118b is within coverage area 952g of propeller assembly 116g, (ii) control surface 118b is entirely within coverage area 952h of propeller assembly 116h, and (iii) a portion of control surface 118b is within coverage area 952i of propeller assembly 116i. Yet still further, control surface 120b is within both coverage area 952k of propeller assembly 116k and coverage area 9521 of propeller assembly 1161.

[0213] It should be understood that this example is representative, and other arrangements are possible as well. For instance, while Figure 9B illustrates each of control surfaces 120a-b as being entirely within the coverage area of a first propeller and the coverage area of a second propeller, in other examples, only a portion of those control surfaces are within both a coverage area of a first propeller and a coverage area of a second propeller. Other examples are possible as well.

[0214] As another example, in some scenarios, the coverage area of adjacent propellers may not overlap. In such an example, some of the adjacent propellers may each include a respective different portion of a control surface. For instance, with reference to Figure 9C, the propeller 116g’may have a coverage area 952g’ and blow air over a first portion 119 of the control surface 118b’, and adjacent propeller 116h’ may have a coverage area 952h’ and blow over a different second portion 121 of the control surface 118b’. In this example, even though the coverage areas 952g’ and 952h’ do not overlap with one another, the adjacent propellers may still cover for one another if the other goes offline by virtue of each blowing a respective portion of the same control surface. Other examples are possible as well.

[0215] For some craft, certain portions of the wing 104 may have a greater influence on lift and / or control than other portions of the wing. For instance, in some examples, an outer portion of the wing may have a greater influence on lift and control than an inner portion of the wing 104. Thus, in some examples, the selection of particular sets of propeller motors that are paired with different sets of batteries may take the portions of the wing (and relative effect on lift and / control of the craft) into account.

[0216] In an example, in order to ensure that the outer portion of the wing near the wing tip maintains at least some air being blown on it, for a given respective set of propeller motors, the one propeller of the one or more starboard- si de propellers and the one or more port-side propellers may be arranged proximate to a wing tip, and each of the other propellers of the one or more starboard- si de propellers and the one or more port-side propellers may be arranged between propellers associated with one or more different sets of propeller motors. One example of such a set of propellers is the propellers associated with set of motors 904. Another example of such a set of propellers is the propellers associated with set of motors 934. In such an arrangement, the propeller proximate to the wing tip is associated with a different set of motors than the propeller adjacent to the propeller proximate to the wing tip. Thus, this arrangement will help ensure that, even if the set of motors associated with the propeller proximate to the wing tip goes offline, a propeller adj acent to the propeller proximate to the wing tip can still blow air over the outer portion of the wing near the wing tip.

[0217] In some examples, the particular sets of propeller motors that are paired with different sets of batteries are selected so as to provide symmetry or at least a level of symmetry on the port side and starboard side of the craft. Such symmetry or at least a level of symmetry on the port side and starboard side of the craft may help to ensure that the craft is able to maintain sufficient lift and / or control of the craft even in a scenario where one of the sets of motors goes offline for one reason or another.

[0218] In order to provide at least a level of symmetry, for each respective set of propeller motors, one of the one or more starboard-side propellers and one of the one or more of the port- side-propellers are arranged at substantially the same distance from the hull. Further, in someexamples where each respective set of propeller motors includes port-side and starboard- si de propellers arranged at substantially the same distance from the hull, the other one or more propellers associated with the respective set of propeller motors are arranged further from the hull. For instance, in the illustrative example of Figures 9A-B, for the set of propellers motors 914, the propellers arranged at substantially the same distance from the hull comprise (i) a starboard- si de propeller that is a first propeller from the hull on the starboard side and (ii) a port-side propeller that is a first propeller from the hull on the port side, and the other one or more propellers associated with the respective set of propeller motors is a fifth propeller from the hull on the port side.

[0219] Further, for set of propeller motors 924, the propellers arranged at substantially the same distance from the hull comprise (i) a starboard-side propeller that is a second propeller from the hull on the starboard side and (ii) a port-side propeller that is a second propeller from the hull on the port side, and the other one or more propellers associated with the respective set of propeller motors is a fifth propeller from the hull on the starboard side.

[0220] Still further, for set of propeller motors 904, the propellers arranged at substantially the same distance from the hull comprise (i) a starboard- si de propeller that is a third propeller from the hull on the starboard side and (ii) a port-side propeller that is a third propeller from the hull on the port side, and the other one or more propellers associated with the respective set of propeller motors is a sixth propeller from the hull on the port side.

[0221] And yet still further, for set of propeller motors 934, the propellers arranged at substantially the same distance from the hull comprise (i) a starboard-side propeller that is a fourth propeller from the hull on the starboard side and (ii) a port-side propeller that is a fourth propeller from the hull on the port side, and the other one or more propellers associated with the respective set of propeller motors is a sixth propeller from the hull on the starboard side.

[0222] Of course, in another example, the motors arranged further from the hull could each be on opposite sides. More particularly, (i) for the set of propellers motors 914, rather than including a fifth propeller from the hull on the port side, the set could include the fifth propeller from the hull on the starboard side; (ii) for the set of propeller motors 924, rather than including the fifth propeller from the hull on the starboard side, the set could include the fifth propeller from the hull on the port side; (iii) for set of propeller motors 904, rather than including the sixth propeller from the hull on the port side, the set could include the sixth propeller from the hull on the starboard side; and (iv) for set of propeller motors 934, rather than including the sixth propeller from the hull on the starboard side, the set could include the sixth propeller from the hull on the port side.

[0223] Further, in this example of Figures 9A-B, for each respective set of propeller motors, the one or more starboard- si de propellers associated with the one or more of the starboard- si depropeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port-side-propeller motors. However, in other examples, for each respective set of propeller motors, the number of the one or more starboardside propellers associated with the one or more of the starboard-side-propeller motors may be the same as the number of the one or more port-side propellers associated with the one or more of the port-side-propeller motors.

[0224] Still further, in this example of Figures 9A-B, there are four sets of batteries and four corresponding sets of propeller motors. However, in other examples, there may be more or fewer sets of batteries and corresponding sets of propeller motors. For instance, rather than four sets of batteries driving all 12 motors as depicted in Figure 9a, in another example, three sets of batteries may drive all 12 motors. In another example, five sets of batteries may drive all 12 motors. Other examples are possible as well.

[0225] It should be understood that the Figures 9A-B depict a representative example of a battery system and particular sets of propellers motors, and other example (i) sets of batteries and (ii) corresponding sets of motors are possible as well. In this regard, the (i) sets of batteries and (ii) corresponding sets of motors may vary based on any of various factors including, for instance, the number of propellers on the craft, the number of sets of batteries of the battery system, the coverage area of the propellers on the craft, the control surfaces on the one or more wings of the craft, and / or the positioning of propellers relative to portions of the one or more wings, among other possibilities.

[0226] As additional representative examples, Figures 9D-F illustrate additional example schematics of the battery system 400 in which the sets of batteries are associated with different corresponding sets of motors.

[0227] In particular, with reference Figure 9D, in this example, the battery system 400 includes the plurality 901 of sets of batteries, where the plurality 901 of sets of batteries includes: (i) a first set of batteries 902’ configured to provide power to a first set of motors 904’; (ii) a second set of batteries 912’ configured to provide power to a second set of motors 914’; (iii) a third set of batteries 922’ configured to provide power to a third set of motors 924’; and (ii) a fourth set of batteries 932’ configured to provide power to a fourth set of motors 934’.

[0228] In this example of Figure 9D, first set of motors 904’ includes motors 115c, 115i, and 1151, second set of motors 914’ includes motors 115b, 115e, and 115h, third set of motors 924’ includes motors 115f, 115g, and 115k, and fourth set of motors 934’ includes motors 115a, 115d, and 115j.As mentioned above, the (i) sets of batteries and (ii) corresponding sets of motors may vary based on various factors. Along these lines, this example arrangement of sets of motors in Figure 9C helps to avoid same side failures near the ailerons of the wing.

[0229] Further, with reference Figure 9E, in this example, the battery system 400 includes the plurality 901 of sets of batteries, where the plurality 901 of sets of batteries includes: (i) a first set of batteries 902” configured to provide power to a first set of motors 904”; (ii) a second set of batteries 912” configured to provide power to a second set of motors 914”; (iii) a third set of batteries 922” configured to provide power to a third set of motors 924”; and (ii) a fourth set of batteries 932” configured to provide power to a fourth set of motors 934”.

[0230] In this example of Figure 9E, first set of motors 904” includes motors 115d, 115i, and 1151, second set of motors 914” includes motors 115b, 115e, and 115h, third set of motors 924” includes motors 115f, 115g, and 115k, and fourth set of motors 934” includes motors 115a, 115c, and 115j. As mentioned above, the (i) sets of batteries and (ii) corresponding sets of motors may vary based on various factors. Along these lines, this example arrangement of sets of motors in Figure 9D helps to limit any failures inboard to symmetric failures.

[0231] Still further, with reference Figure 9F, in this example, the battery system 400 includes the plurality 901 of sets of batteries, where the plurality 901 of sets of batteries includes: (i) a first set of batteries 902”’ configured to provide power to a first set of motors 904”’; (ii) a second set of batteries 912’” configured to provide power to a second set of motors 914’”; (iii) a third set of batteries 922’ ’ ’ configured to provide power to a third set of motors 924” ’ ; and (ii) a fourth set of batteries 932’” configured to provide power to a fourth set of motors 934’”.

[0232] In this example of Figure 9F, first set of motors 904’” includes motors 115d, 115f, and 1151, second set of motors 914’” includes motors 115b, 115e, and 115i, third set of motors 924’” includes motors 115c, 115h, and 115k, and fourth set of motors 934’” includes motors 115a, 115g, and 115j. As mentioned above, the (i) sets of batteries and (ii) corresponding sets of motors may vary based on various factors. Along these lines, this example arrangement of sets of motors in Figure 9E helps to ensure that as many propellers blow air at ailerons of the wing as possible.

[0233] Further, as mentioned above, the sets of motors may be selected so as to balance positioning along the wing of propellers in addition to or alternative to ensuring that for each respective propeller in a given set of propellers, a coverage area associated with air that is blown by that respective propeller overlaps at least in part with a coverage area of air that is blown by a propeller from a different set of propellers. For instance, in some examples, even if the propellers of a craft do not have overlapping coverage areas and / or regardless of whether the propellers of a craft do not have overlapping coverage areas, the sets of motors may be selected such thatpropeller motors within a given set will be associated with propellers that are distributed along the wing such that, if the set goes offline, the lost propellers and propeller motors will not all be localized to a particular area of the wing. Additionally or alternatively, the sets of motors may be selected such that the set includes at least two motors that have similar positioning on different sides of the wing. For instance, the set may include (i) a propeller motor for a propeller on the left wing and (ii) a propeller motor for a propeller on the right wing, and the position of these two propellers (e.g., distance from the hull) are similar, which helps to maintain control authority (e.g., roll and yaw authority) by not creating an imbalance.

[0234] The sets of batteries 902, 912, 922, and 932 may take any of various forms. In general, each set of batteries 902, 912, 922, and 932 may include any battery or batteries that are configured to provide sufficient power to operate the set of motors with which the set of batteries is associated (perhaps along with other equipment of the craft 100 to which the set of batteries may also be connected).

[0235] In some examples, for each respective set of batteries, batteries from the respective set of batteries are arranged within one or more battery subsystems of the battery system. The battery subsystems may take any of various forms, examples of which are described with reference to FIGS. 10A-12. At a high-level, a battery subsystem may include one or more batteries, a battery power management unit (BPMU), and, optionally, one or more disconnect modules.

[0236] Turning first to the one or more batteries, Figure 10A illustrates an example battery 1002 (which may also be referred to as a “battery module”). Any suitable type of battery is possible including, for instance, a lithium-ion battery, a magnesium-ion battery, or a lithium-sulfur battery, among other possibilities. Further, the battery 1002 may be configured to provide any suitable voltage. In some examples, the voltage may depend on various factors including, for instance, power requirements of the propeller motors, number of other batteries in the battery system, and / or safety requirements, among other possibilities.

[0237] The battery 1002 may have one or more interconnects. For instance, the battery 1002 may have (i) a first interconnect for high voltage connection and (ii) a second interconnect for communications and / or control of the battery. Other interconnects are possible as well.

[0238] As mentioned above, the battery subsystem may include one or more batteries. In an example where a battery subsystem includes a plurality of batteries 1002, the batteries 1002 may be connected in series, so as to provide a desired voltage for the battery subsystem. An example battery subsystem having a plurality of batteries 1002 connected together in series is described in further detail below with reference to Figure 10D.

[0239] Turning next to the BPMU, Figure 1 OB illustrates an example BPMU 1004 for managing a battery subsystem and / or the one or more batteries of the battery subsystem. In general, managing the battery subsystem and / or the one or more batteries of the battery subsystem may involve any suitable management functions including, for instance, monitoring various aspects of the operation of the battery subsystem and / or the one or more batteries 1002, controlling the operation of the battery subsystem and / or the one or more batteries 1002, and providing notifications related to the operation of the battery subsystem and / or the one or more batteries 1002, among other possibilities.

[0240] BPMU 1004 may be configured to manage the battery subsystem and / or the one or more batteries of the battery subsystem during operation of the craft. For instance, BPMU 1004 may monitor and control operation of the battery subsystem and / or the one or more batteries 1002 during flight of the craft 100. BPMU 1004 may also provide notifications regarding a malfunction(s) of the one or more batteries 1002, overheating of the one or more batteries 1002, charge status of the one or more batteries 1002, and so forth.

[0241] BPMU may also be configured to manage the battery subsystem and / or the one or more batteries of the battery subsystem during charging of the battery system. For instance, BPMU 1004 may monitor the charge status of each battery 1002 of the battery subsystem, so as to ensure that the batteries 1002 do not overheat or overcharge. In an example, if BPMU 1004 detects that one or more of the batteries 1002 exceeds a threshold temperature during charging, BPMU 1004 may stop charging of the battery subsystem. Other examples of managing the battery subsystem and / or the one or more batteries of the battery subsystem are possible as well.

[0242] Turning next to the disconnect module, Figure 10C illustrates an example disconnect module 1006. In general, disconnect module 1006 is configured to separate a first battery subset in a battery subsystem from a second battery subset in the battery subsystem. Separating a first battery subset in a battery subsystem from a second battery subset in the battery subsystem may beneficially help to separate a battery subsystem having a total overall voltage into two lower voltage subsets of batteries. The disconnect module 1006 may include a fuse. Any suitable fuse is possible including, for instance, a fuse configured to trip once a threshold current is exceeded. The threshold may be any suitable value, such as 100 ampere (A), 200 A, 300 A, and so forth.

[0243] In some examples, the disconnect module 1006 may include use of sophisticated fuse elements (e.g., programmable fuse elements), such as fuse elements that are configured to trip on a combination of triggers or to trip or when a threshold current is exceeded for predetermined amount of time (versus configured to trip once a threshold current is exceeded). While a fuse configured to trip once a threshold current is exceeded may provide numerous safety benefits, insome situations such a fuse may risk tripping in undesired situations and interrupting battery power in normal operation. A programmable fuse element may help the disconnect module 1006 avoid tripping in undesired situations and interrupting battery power in normal operation. Further, the programmable fuse element may be programmable such that it is configured to dynamically change its operation during flight based on operational state and / or operational requirements (e.g., the programmable fuse element may dynamically change its operation based on mode of operation of the craft, among other possibilities).

[0244] A fuse and / or programmable fuse elements may beneficially provide a layer of safety both during operation of the craft 100 (e.g., the fuse may help to protect the motors and / or or other components of the craft 100 connected to the battery subsystem) and / or during repair and maintenance of the craft 100 (e.g., providing a layer of safety for a technician repairing the battery system of the craft).

[0245] Within examples, a collection of batteries 1002, BPMU 1004, and disconnect module 1006 may be used to form a battery subsystem of a set of batteries (e.g., set of batteries 902, set of batteries 912, set of batteries 922, or set of batteries 932). Figure 10D illustrates an example battery subsystem 1050 that includes a first battery subset 1052, a second battery subset 1054, a disconnect module 1006, and BPMU 1004. Disconnect module 1006 separates the first battery subset 1052 from the second battery subset 1054.

[0246] The first battery subset 1052 and the second battery subset 1054 may take any of various forms. In general, a battery subset could be a single battery or some collection of a plurality of batteries. In this example battery subsystem 1150 of Figure 10D, the first battery subset takes the form of battery pack 1060 and battery pack 1062, and the second battery subset 1054 takes the form of battery pack 1064. Each battery pack of battery packs 1060, 1062, and 1064 is a string of six (6) batteries, and each individual battery in the battery packs may correspond to battery 1002 (see Figure 10a).

[0247] As discussed above, the batteries 1002 may be connected in series, so as to provide a desired voltage for the battery subsystem. In battery subsystem 1050, the individual batteries in each battery pack may be connected in series, and the battery packs may also be connected in series. The voltage of the individual batteries and / or the number of batteries in the battery packs may be selected to provide any desired voltage for the battery subsystem 1050. As an illustrative example, the desired voltage to be provided by the battery subsystem may be 800 V. In the example of Figure 10D, each battery 1002 may be a 44.5 V battery. Further, in a situation where each battery 1002 in the battery packs is a 44.5 V battery, each battery pack may provide an approximately 267 V battery pack. In turn, when battery packs 1060, 1062, and 1064 areconnected in series, battery subsystem 1050 may provide an approximately 800 V battery subsystem. Other examples are possible as well.

[0248] Beneficially, the disconnect module 1006 provides separation of the subsets of batteries, which may serve to improve workability and / or maintenance of the battery subsystem 1050. For instance, in a scenario where the battery subsystem includes a set of batteries providing 800 V, one or more of the battery subsets may malfunction (e.g., overheat) but the disconnect module 1006 may help to serve to keep the other battery subset safe. The individual battery subsets can be removed and / or replaced as needed (versus, e.g., needing to replace an entire 800 volt set of batteries). As another example, the disconnect module can be used for safety when working on the individual battery packs (e.g., providing overcurrent protection). As yet another example, the disconnect module may provide a lower working voltage (in general, it may be desirable to decrease the voltage of a given battery subset).

[0249] It should be understood that the battery subsystem of Figure 10D is intended as an example only, and other example battery subsystems are possible as well. For instance, as one possibility, while this example of Figure 10D depicts the battery subsets as taking the form of one or more battery packs, other example battery subsets are possible as well. As one possibility, the first battery subset may be a single battery and the second battery subset may be a different, single battery. As another possibility, the battery subsystem may include more or fewer subsets of batteries, more or fewer disconnect modules, and / or more or fewer BPMUs.

[0250] As yet another possibility, one or more components of the battery subsystem 1050 may be integrated with other components of the battery subsystem. For instance, while Figure 10D illustrates a disconnect module 1006 that is physically separate from the battery packs (i.e., a separate module that is wired or otherwise connected to the battery packs), in other examples the disconnect module 1006 may be integrated into one of the battery packs and / or into one of batteries. Similarly, while Figure 10D illustrates BPMU 1004 as being physically separate from the battery packs, in other examples, the BPMU may be integrated into the battery pack or an individual battery 1002 itself. Other examples are possible as well.

[0251] As mentioned above, for each respective set of batteries of the battery system 400, batteries from the respective set of batteries are arranged within one or more battery subsystems of the battery system. The respective set of battery subsystems may include any suitable number of battery subsystems. In an example, the respective set of batteries may include two or more battery subsystems. Providing two or more battery subsystems may help to provide a layer of redundancy for a given set of motors.

[0252] A representative example in which battery system 400 includes two battery subsystems for each set of batteries 902, 912, 922, and 932 is described with reference to Figures 11 and 12. In particular, Figure 11 illustrates a perspective view of battery system 400 that includes eight battery subsystems, and Figure 12 is a schematic of this battery system 400 that illustrates the particular connections of the eight battery subsystems to sets of propeller motors.

[0253] With reference to both Figures 11 and 12, the battery system 400 includes battery subsystem 1110, 1120, 1130, 1140, 1150, 1160, 1170, and 1180 (noting that, in Figure 11, battery subsystems 1160, 1170, and 1180 are hidden from view). As shown in Figure 12, each set of batteries 902, 912, 922, and 932 are arranged within two battery subsystems. More particularly, set of batteries 902 is arranged within battery subsystems 1110 and 1120. Battery subsystem 1110 includes battery string 1212 and BPMU 1214, and battery subsystem 1120 includes battery string 1222 and BPMU 1224. Further, set of batteries 912 is arranged within battery subsystems 1130 and 1140. Battery subsystem 1130 includes battery string 1232 and BPMU 1234, and battery subsystem 1140 includes battery string 1242 and BPMU 1244. Still further, set of batteries 922 is arranged within battery subsystems 1150 and 1160. Battery subsystem 1150 includes battery string 1252 and BPMU 1254, and battery subsystem 1160 includes battery string 1262 and BPMU 1264. Yet still further, set of batteries 912 is arranged within battery subsystems 1170 and 1180. Battery subsystem 1170 includes battery string 1272 and BPMU 1274, and battery subsystem 1180 includes battery string 1282 and BPMU 1284. Although not shown in Figure 12, as described with reference to Figure 10D, each battery string may also comprise a disconnect module 1006 separating a first battery subset of the battery subsystem from a second battery subset of the battery subsystem.

[0254] The sets of battery subsystems are connected to BUSes, which are in turn connected to the sets of motors. In particular, (i) battery subsystems 1110 and 1120 are connected to BUS 1286, which is in turn connected to first set of motors 904, (ii) battery subsystems 1130 and 1140 are connected to BUS 1288, which is in turn connected to second set of motors 914, (iii) battery subsystems 1150 and 1160 are connected to BUS 1290, which is in turn connected to third set of motors 924, and (iv) battery subsystems 1170 and 1180 are connected to BUS 1292, which is in turn connected to fourth set of motors 934.

[0255] Each respective BUS may be connected to one of the sets of propeller motors via a respective set of wires having a respective total length. In an example, the respective total lengths of the sets of wires for each respective BUS are substantially equal to one another. In general, the longer the line length of wires from a BUS to a set of propeller motors, the more voltage loss there will be between the batteries and the set of propeller motors. Thus, if the sets of wires haddifferent lengths, different sets of motors may be provided with different voltages during operation. On the other hand, having wires with total length substantially equal to one another may help to ensure that each BUS provides a substantially similar voltage during operation (e.g., during take-off and cruise operations). As used herein, a given length is substantially the same length to another length of the given length is within 5% of the other length.

[0256] In the example of Figure 12, each BUS is connected to two battery subsystems. Providing two battery subsystems for each BUS helps to provide a layer of redundancy for sets of propeller motors. In this regard, each battery subsystem may be configured to provide sufficient voltage to operate the set of propeller motors with which the string is associated. For instance, each battery subsystem may be capable of providing sufficient voltage to the respective set of motors (e.g., 800V). Thus, even if one of the battery subsystems goes offline for one reason or another, the remaining battery subsystem may provide at least some amount of voltage to operate, either fully or partially, that set of propeller motors.

[0257] In other examples, each BUS may be connected to more or fewer battery subsystems. In an example, additional subsystems may help the battery system 400 to help better maintain constant voltage draw. For instance, more battery subsystems may help voltage to sag less, thus resulting in a more constant voltage being supplied to a set of motors.

[0258] Further, in the example of Figure 12, each string is connected to its own BPMU. However, other arrangements of BPMUs are possible as well. For instance, in an example, rather than each battery subsystem including a BPMU, a single BPMU may control both strings. In other words, rather than each string of a set of batteries including being connected to its own BPMU, the two strings may both be connected to a single BPMU. As another example, each battery pack within a string may be connected to its own BPMU (e.g., each BPMU might be physically integrated with a battery pack).

[0259] Still further, in the example of Figure 12, each BUS is connected to two battery subsystems but is not connectable to the other battery subsystems of the battery system 400. However, in other examples, the battery system 400 may be configured such that the connections of the strings to BUSes may be dynamically reconfigured. For instance, the battery system 400 may be configured to dynamically change the connection of a given string from one BUS to another BUS. This dynamic reconfiguration may help to manage voltage being provided to the propeller motors (or other equipment connected to the BUS).V. Example Mounting System for Battery System

[0260] In accordance with the present disclosure, a new mounting system for a battery system of a craft is also provided. The mounting system may be configured to mount a battery systemsuch as batery system 400 within the craft 100. In general, the mounting system may be configured to support the battery system and secure the battery system in the craft. The mounting system may include (i) a starboard stringer, (ii) a port stringer, (iii) a plurality of crossbeams arranged between the starboard stringer and the port stringer, and (iv) a plurality of hangar brackets for supporting the plurality of sets of bateries.

[0261] An example mounting system is described with reference to FIGS. 13 and 14A-E. Turning first to Figure 13, example mounting system 1300 includes a starboard stringer 1302, a port stringer 1304, a plurality of crossbeams 1306 arranged between the starboard stringer 1302 and port stringer 1304, and a plurality of hangar brackets 1308 for supporting the plurality of sets of batteries of the battery system 400.

[0262] For purposes of illustration and clarity, Figure 13 shows a single battery pack 1310 being supported by two hangar brackets 1308. However, it should be understood that each battery pack of battery system 400 may be supported by a set of hangar brackets. In this regard, Figures. 15A- B illustrates multiple battery packs 1310 supported by mounting system 1300.

[0263] Figure 14A illustrates a perspective view of an example hangar bracket 1308. The hangar bracket includes a lip 1309 for connecting to a crossbeam 1306 as well as a ledge 1311 for supporting a battery pack 1310. Each hangar bracket 1308 is configured to support a single one of the batery packs 1310. In the example of Figure 13, mounting system 1300 includes (i) a first hangar bracket 1308 is on a port side 1312 of battery pack 1310 and (ii) a second hangar bracket (not shown) on a starboard side 1314 of battery pack 1310. While the example Figure 13 illustrates two hangar brackets for a battery pack, other examples are possible as well. For instance, the hangar brackets may be configured such that a single hangar bracket is configured to hold a battery pack. In another example, a hangar bracket may be configured to support a plurality of battery packs. Other examples are possible as well.

[0264] The hangar brackets 1308 may be connected to the crossbeams in any suitable manner. In an example, hangar clamps are utilized to connect the hanger brackets 1308 to the crossbeams 1306. For instance, with reference to FIGS. 13 and 14B, an example hangar clamp 1316 is illustrated. Hangar clamp 1316 includes fastener hole 1318, which may receive a fastener for securing the hangar clamp 1316 to crossbeam 1306.

[0265] In an example, the crossbeams 1306 of the mounting system 1300 are connected to the starboard stringer 1302 and port stringer 1304 via crossbeam hangars. Each crossbeam hangars may include (i) one or more fastener holes each configured to receive fasteners for fastening a crossbeam hangar to one of the stringers and (ii) and a slot to receive the crossbeam. Further, each crossbeam hangar may also include fastener holes for receiving fasteners to secure the crossbeamto the crossbeam hangar, as well as one or more fastener holes for receiving fasteners to secure the crossbeam to the crossbeam hangar. For instance, with reference to Figures 13 and 14C, crossbeams 1306 beams are connected to starboard stringer 1302 and port stringer 1304 via crossbeam hangars 1322. Crossbeam hangar 1322 includes fastener holes 1320 each configured to receive fasteners for fastening crossbeam hangar 1322 to one of starboard stringer 1302 or port stringer 1304. Crossbeam hangar 1322 also includes a slot 1323 configured to receive and support crossbeam 1306. Further, crossbeam hangar 1322 also includes fastener holes fastener holes 1324 for receiving fasteners to secure crossbeam 1306 to crossbeam hangar 1322.

[0266] Crossbeam 1306 may have a corresponding fastener hole. For instance, with reference to Figure 14D, a perspective view of crossbeam 1306 is illustrated. Crossbeam 1306 includes corresponding fastener holes 1326 for receiving fasteners to secure crossbeam 1306 to crossbeam hangar 1322.

[0267] Further, in an example, the mounting system 1300 also includes a plurality of stiffening brackets, where each stiffening bracket is configured to stiffen one of the battery packs 1310. In general, the stiffening bracket may be an elongated beam that is configured to attach to a battery and / or battery pack. Figure 14E illustrates a perspective view of an example stiffening bracket 1330. In an example, stiffening bracket may take the form of a L-shape, so as to provide stiffening on two surfaces of the battery pack, such as the top and side of battery pack as shown in Figure 13. As used herein, L-shaped means having the general shape of the letter “L” or resembling an “L” in cross section. Other shapes are possible as well.

[0268] One or more stiffening brackets may be utilized to stiffen a single battery pack 1310. For instance, with reference to FIGS. 13, mounting system 1300 includes (i) a first stiffening bracket 1330 on port side 1312 of battery pack 1310 and (ii) a second stiffening bracket (not shown) on starboard side 1314 of battery pack 1310. Stiffening bracket(s) 1330 may be attached to battery pack 1310 in any suitable fashion including, for instance via adhesive, fasteners, and / or clamps, among other possibilities.

[0269] Beneficially, the stiffening bracket 1330 may provide rigidity to the battery pack 1310 and prevent individual batteries from moving or shifting position when mounted within mounting system 1300. Providing stiffness and rigidity to individual components of the battery system may also help to improve the overall stiffness and rigidity of the craft 100.

[0270] In some examples, stiffening elements for the battery system 400 (e.g., a stiffening element such as stiffening bracket 1330) may be provided as an integral member of the hull structure of the craft 100. Stiffening elements for the battery system provided as an integral member of the hull structure may be referred to as a structural or integrated battery casing. Sucha structural or integrated battery casing can help to systematically reduce hull / fuselage mass of the craft 100.

[0271] In an example, the battery system 400 is positioned in the craft such that the center of gravity of the battery system is substantially aligned with a center of gravity of a remainder of the craft. Within examples, the battery system 400 of the craft 100 may account for a significant portion of the weight of the overall craft, For instance, in some examples, the battery system 400 may account for approximately 1 / 3 of the overall weight of craft 100 (or perhaps even higher). Therefore, the battery system 400 may be positioned within the craft at a position such that the center of gravity of the battery system aligns or substantially aligns with a center of gravity of the remainder of the craft. Thus, the position of the mounting system 1300 may be selected so as to ensure that battery system 400 is positioned in the craft such that the center of gravity of the battery system is substantially aligned with a center of gravity of a remainder of the craft.VI. Example Battery Bay and Hatches for Accessing Battery Bay

[0272] Within examples, the battery system 400 is positioned in a battery bay of the hull of the craft. The arrangement of the battery system 400 within the battery bay, as well as access to the battery bay (e.g., for the installation and / or repair and maintenance of the battery system 400) is described with reference to Figures 15A-B and 16A-B.

[0273] As shown in Figures 15A-B, the craft 100 includes a battery bay 1510, and the battery bay 1510 includes the battery system 400 and mounting system 1300. Further, with reference to Figure 16A, the craft 100 further includes flooring 1602 which separates battery bay 1510 from the passenger seating area 404 (see Figure 4). Flooring 1602 is configured to allow access to battery bay 1510. In this regard, flooring 1602 may include a plurality of hatches 1610. The access provided by the hatches may be utilized during installation of the battery system 400 and / or repair and maintenance of the battery system 400.

[0274] Any suitable number and / or arrangement of hatches are possible. In an example, flooring comprises a first hatch and a second hatch configured to provide access to the battery bay 1510, and a first subset of the plurality of sets of batteries are accessible through the first hatch and a second subset of the plurality of sets of batteries are accessible through the second hatch. For instance, with reference to Figures 16A-B, a first subset 1612 of the plurality of sets of batteries are accessible through first hatch 1610A and a second subset 1614 of the plurality of sets of batteries are accessible through second hatch 1610B.

[0275] The flooring 1602 may also include other hatches configured to provide access to different parts of the battery system and / or battery bay. As one possibility, flooring 1602 may further include one or more hatches configured to provide access to the BPMUs of the batterysystem. For instance, in the example of Figure 16A, flooring 1602 includes BPMU hatches 1610c and 161 Od. As another possibility, flooring 1602 may include one or more hatches configured to provide access to the disconnect modules of the battery system. For instance, in the example of Figure 16A, flooring may include hatch 1610e which may provide access to disconnect modules. As yet another possibility, the flooring 1602 may include one or more hatches configured to access other parts of the battery bay, such as hatches 1610f and 1610g. Other example hatches are possible as well.

[0276] The arrangement of the battery system 400 within the battery bay 1510 (e.g., the arrangement of components of the battery system relative to one another), as well as the plurality of hatches and their associated locations, may help to facilitate efficient installation and / or repair and maintenance of the battery system 400.

[0277] Turning first to installation, the battery system 400 is arranged such that different portions of the battery system may be conveniently installed via different hatches. For instance, first subset 1612 may be installed via hatch 1610a, second subset 1614 may be installed via hatch 1610b, the BPMUs may also be installed via hatches 1610c-d, and the disconnect modules may be installed via hatch 1610c.

[0278] The batteries of the battery system 400 may be installed in any suitable order. In an example, the battery system includes multiple levels. For instance, with reference to Figure 11, the battery system 400 includes a first level 1190, a second level 1192, and a third level 1194. In this example, first level 1190 includes a single battery pack 1310, second level 1192 includes 11 battery packs 1310, and third level 1194 includes 12 battery packs 1310.

[0279] These different levels of the battery system may be installed in phases. For instance, in an example, level 1190 may be installed via hatch 1610a, level 1192 may be installed via hatches 1610a and 1610b, and then level 1194 may be installed via hatches 1610a and 1610b. Figure 15A shows a stage of an example installation process where first level 1190 (not shown) and second level 1192 are installed, and Figure 15B shows a subsequent stage of the example installation process where third level 1194 is installed.

[0280] In another example, the subsets 1612 and 1614 may be installed sequentially. For instance, first subset 1612 may first be installed via hatch 1610a. After first subset 1612 is installed, second subset 1614 may be installed via hatch 1610b. Other examples are possible as well.

[0281] Although the example of Figures 11 and 16A-B show three battery levels in the battery system 400, more or fewer levels are possible. As discussed in more detail below, the particulararrangement of the batteries of the battery system 400 may depend on various factors including, for instance, the shape of the battery bay, among other possibilities.

[0282] Turning next to repair and maintenance, the arrangement of the battery system 400 and the hatches 1610 help to facilitate efficient repair and / or maintenance of the battery system 400. In an example, the BPMUs of the battery subsystems are arranged on either a fore side or an aft side of the battery system, and the disconnect modules of the battery subsystems are arranged on the other of the fore side or the aft side of the battery system. For instance, in the example of Figures 11 and 16A-B, the BPMUs are arranged on a fore side 1630 of the battery system, and the disconnect modules are arranged on an aft side 1632 of the battery system. By having all the BPMUs arranged proximate to one another, and all the disconnect module modules arranged proximate to one another, a technician may conveniently access the entire sets of BPMUs for repair and / or maintenance. For instance, a technician may conveniently access all the BPMUs via hatches 1610c-d. Similarly, by having all the disconnect modules proximate to one another, a technician may conveniently access the entire sets of BPMUs for repair and / or maintenance. For instance, a technician may conveniently access all the disconnect modules via hatch 1610e.

[0283] In addition, by having the set of BPMUs arranged on the fore side 1630 and the set of disconnect modules arranged on the aft side 1632 (or, in another example, vice versa), the technician may conveniently access the BPMUs and the disconnect modules without needing to move the batteries around to provide access to the BPMUs and the disconnect modules.

[0284] The batteries of the battery system 400 may also conveniently be accessed via hatches 1610a and 1610b for repair and / or maintenance.

[0285] In this illustrative example of Figures 11 and 16A-B, the battery packs in level 1190 is arranged below level 1192, which is in turn below level 1194. Thus, the battery packs in lower levels can only be accessed by removing the battery packs in the higher level(s). However, other example arrangements are possible. As one example, the arrangement of the batteries may take the form of a honeycomb arrangement that enables access to packs in lower levels without having to remove and / or rearrange the battery packs in the higher level(s).

[0286] As mentioned above, the flooring 1602 separates the battery bay from the passenger seating area. In an example, the flooring 1602 comprises one or more fire retardant materials to thereby provide a firewall between the battery bay and the passenger bay. Various fire retardant materials are possible, including, for instance, fire-resistant fibers (including fire-resistant finished natural fibers and high-performance fibers including synthetic polyamides, carbon, and ceramic fibers), and fiber composite including multi-dimensional woven composite, natural fibercomposite, and fiber metal laminates (FMLs), among other possibilities. In an example, the one or more fire retardant materials utilized are sufficient to provide a 60 minute or higher firewall.

[0287] Further, in an example, the battery bay 1510 and the battery bay hatches 1610 are airtight and / or watertight. By being airtight and watertight, this may help ensure that vented gases from the battery system do not escape to above in the craft, as well as help to ensure that water does not seep through to the battery system.

[0288] In some examples, the number of components in the battery system (e.g., number of battery packs, BPMUs, disconnect modules, etc.) and / or the arrangement of the components relative to one another may vary. The disclosed mounting system may be configured to support number of components in the battery system and various arrangements of the components of the battery system. In this regard, the number of components in the battery system, the arrangement of the components relative to one another, and / or the configuration of the mounting system may depend on the craft in which the battery system is installed. For instance, the number of components in the battery system, the arrangement of the components relative to one another, and / or the configuration of the mounting system may be based on various factors, including, for instance, the shape of the hull of the craft and / or the center of gravity of the craft, among other possibilities.

[0289] As one representative example, the shape of the hull may influence or drive the configuration of mounting system and / or the arrangement of the components of the battery system relative to one another. With reference to FIGS. 15A-B, hull 1502 of craft 100 takes the form of a V-shape. As used herein, V-shaped means having the general shape of the letter “V” or resembling a “V” in cross section. In general, it may be beneficial to reduce or minimize unused space within the battery bay. However, a V-shaped hull may make it difficult to efficiently utilize available space in the hull, which may result in unused space within a battery. In order to overcome this drawback, the battery system 400 may be configured to have multiple levels so as to more efficiently utilize available space within a hull such as a V-shaped hull. Similarly, the mounting system 1300 may be configured to support the multiple levels of the battery system 400.

[0290] As mentioned above, with reference to Figure 10D, the battery system 400 includes first level 1190, second level 1192, and third level 1194. By including these multiple levels, the battery pack is able to conform more closely to the V-shaped hull than would otherwise be possible with fewer levels, which in turn helps to more efficiently utilize space in the battery bay. Further, although three levels are shown in this example, in other examples more levels are possible, which may help to further conform more closely to the V-shaped hull.VII. Example Charge Ports for Battery System

[0291] Within examples, the battery system 400 may be a rechargeable battery system that may be recharged at any suitable time (e.g., between flights of the craft 100). To facilitate charging, the craft may include one or more charge ports. The one or more charge ports may be connected to the battery system via one or more power cables. Further, in an example, each BPMU 1004 of the battery system 400 may be connected to a charge port via at least one of the one or more cables.

[0292] In some examples, the craft 100 may include a plurality of charge ports. A plurality of charge ports may be useful for situations in which a single charge port is unable to provide sufficient throughput to efficiently charge the batteries of the battery system. The number of charge ports utilized / included may vary based on various factors.

[0293] Figure 17 illustrates an example where craft 100 includes a first charge port 1702 and a second charge port 1704. As seen in Figure 17, each charge port is connected to a plurality of positive wires 1706 and a plurality of negative wires 1708. In turn, the positive and negative wires are coupled to the BPMUs, as shown in Figure 18. Further, Figure 18 illustrates an example routing of the wires of the charge port to BPMUs of the battery system. For instance, Figure 18 illustrates four example BPMUs 1006a-d, each connected to one of the positive wires 1706 and one of the negative wires 1708.

[0294] Within examples, the one or more charge ports may be positioned on craft 100 at a location to reduce or minimize the amount and / or weight of cabling connecting the one or more charge ports to the battery system. Beneficially, reducing or limiting the cable for the charge may help to reduce or limit the overall weight of the aircraft. For instance, in an example, charge ports 1702 and 1704 may be positioned on a location proximate to hatch 1610c or 161 Od. Further, first charge port 1702 is connected to the four BPMUs accessible via hatch 1610c, and the second charge port 1704 is connected to the four BPMUs accessible via hatch 1610d. This positioning may help to minimize the length of charging cables, which may in turn help to reduce or minimize the overall weight of the craft 100.VIII. Example Thermal-Management System

[0295] Within examples, the craft 100 includes a thermal-management system for the battery system 400 to manage thermal conditions of the battery system 400. For instance, the thermalmanagement system may be configured to manage thermal runaway situations, dissipate gas vented from the battery system, and / or to actively cool the battery system.

[0296] As indicated above, in some scenarios, the battery system 400 may experience less than optimal performance in which a battery or set of batteries experience thermal runaway. For instance, in an example, one or more cells in a battery may experience failure and, in an extremestate, the cell(s) may spontaneously release all or substantially all of their energy thereby causing a thermal runaway situation.

[0297] Within examples, a thermal runaway situation for a battery may involve various levels of thermal runaway. For instance, a thermal runaway situation for a battery may involve a single cell event (e.g., where a single cell releases all of its energy but issues do not propagate to adjacent cells in the battery). As another example, a thermal runaway situation for a battery may involve cell propagation from a battery module edge (e.g., where a cell near an edge releases all its energy and causes a cascade to other cells in the battery module (e.g., burning from left to right). As yet another example, a thermal runaway situation for a battery may involve cell propagation from a center (e.g., where a cell in the center releases all its energy and causes a cascade to other cells in the battery module in both directions.). A thermal-runaway situation occurring in a battery bay of a craft may result in conditions including (i) exhaust gases, (ii) debris, (iii) increased pressures, (iv) increased temperatures, and / or (v) fire.

[0298] As a representative example of the extreme conditions that may exist in thermal runaway situations, a thermal runaway event may (i) cause a temperature on the order of 1000 degrees Celsius and (ii) cause 1.2 psi of battery module pressure. Further, during such a thermal runaway event, various gases may be released, such as carbon monoxide, carbon dioxide, hydrogen, and / or oxygen. In some scenarios, when combined with water, the released gas may become corrosive and may risk damage to other system components of the craft. Further, the situation may cause debris including, for instance, carbon dust, carbon flakes, or other debris.

[0299] Within examples, the craft 100 includes a thermal-management system for the battery system 400 configured to manage thermal runaway situations. While thermal-runaway situations typically do not occur, the thermal-management system is a precautionary system that helps to enhance the overall safety and reliability of the craft 100. At a high-level, the disclosed thermalmanagement system is configured to be capable of handling such a thermal-runaway situation in a way that both (i) keeps passengers safe from gas, debris, heat, and / or fire that may result from a thermal-runaway situation and (ii) prevents or limits damage to the craft that may otherwise occur in a thermal-runaway situation. The thermal-management system is configured to effectively dissipate heat and / or gas associated with thermal runaway.

[0300] In general, the thermal-management system includes (i) a plurality of battery vents for batteries of a battery system and (ii) a duct system. Each battery vent of the plurality of battery vents is (i) coupled to a respective battery of the battery system and (ii) configured to transition from a sealed state to an open state at a threshold temperature. Further, the duct system includes (i) ducting arranged adjacent to the plurality of battery vents and (ii) a manifold (a) connecting theducting arranged adjacent to the plurality of battery vents and (b) including one or more manifold exits. The duct system is configured to exhaust gas away from the battery system when one or more of the battery vents are in the open state.

[0301] Figure 19 illustrates an example thermal -management system 1900 for the battery system 400 of the craft 100. For simplicity, various components (e.g., the BPMUs and disconnect modules) of battery system 400 illustrated in Figure 11 are not included in the depiction of the battery system 400 in Figure 19.

[0302] Thermal-management system 1900 includes a plurality of battery vents 1902 and duct system 1904. Each battery vent 1902 is (i) coupled to a respective battery 1002 of battery system 400 and (ii) configured to transition from a sealed state to an open state at a threshold temperature. Duct system 1904 includes (i) ducting 1906 arranged adjacent to the plurality of battery vents 1902 and (ii) a manifold 1908 (a) connecting ducting 1906 arranged adjacent to the plurality of battery vents 1902 and (b) comprising one or more manifold exits 1910. Duct system 1904 is configured to exhaust gas away from the battery system when one or more of the battery vents are in the open state.A. Example Battery Vents

[0303] The battery vents 1902 may take any of various forms. In general, each battery vent 1902 is configured to (i) be in a sealed state during normal operation of the craft 100 and (ii) open when hot gases need to be removed by the thermal-management system 1900 (e.g., when there is a battery failure such as an emergency thermal runaway situation). In the sealed state, each battery vent 1902 may (i) prevent material from entering the battery vent 1902 but (ii) allow airflow out of the battery vent 1902 to regulate pressure during operation of the battery 1002 associated with the battery vent 1902. In this regard, each battery vent 1902 may function like a gasket to let the battery 1002 release some pressure if there is a pressure build up during normal operation of the battery 1002 (e.g., pressure build up due to changing temperatures in the battery bay during normal operation).

[0304] Within examples, each battery vent 1902 may include a cover that is configured to (i) prevent material from entering the battery vent 1902 but (ii) allow airflow in and / or out of the battery vent 1902 to regulate pressure during operation of the battery 1002 associated with the battery vent 1902. The cover may prevent material such as liquid and / or particulates from entering the battery vent 1902, thereby preventing material such as liquid and / or particulates from entering the battery itself.

[0305] In an example, the cover may be a cap that is positioned in an opening of the battery vent 1902. Further, the cap may be secured in any suitable way including, for instance, via a frictionfit with the opening, adhesive, and / or sealant, among other possibilities. Still further, in some examples, the cover may include one or more pressure vents that may seal the vent but allow for pressure release during normal operation of the battery. In general, the pressure vents may (i) prevent material from entering the battery vent but (ii) allow airflow out of the battery vent to regulate pressure during operation of the battery associated with the battery vent. Any suitable pressure vents are possible including, for instance, GORE® Pressure Vents, among other possibilities.

[0306] In an example, the cover comprises a material that is configured to melt at the threshold temperatures. By melting at the threshold temperature, the cover will melt away or substantially melt away, thereby causing the battery vent to transition to the open state. In general, any suitable material of battery-vent cover is possible including, for instance, a Thermoplastic polyurethane (TPU) material or a ceramic material (e.g., fibrous ceramic), among other possibilities.

[0307] The battery vents 1902 may be configured to transition from a sealed state to an open state at various temperatures. Any suitable threshold temperature is possible and, in general, the threshold temperature is a temperature that typically does not occur during normal operation but may occur in a thermal runaway situation. For instance, in some examples, the threshold temperature may be 200 degrees Celsius or higher. Other examples are possible as well.

[0308] In some examples, each battery vent of the thermal -managem ent system 1900 may be configured to transition at the same threshold temperature. However, in other examples, different battery vents of the thermal-management system may be configured to transition at different temperatures. For instance, a first set of battery vents may transition at a first temperature (e.g., 150 degrees Celsius), and a second set of battery vents may transition at a second temperature (e.g., 200 degrees Celsius). Other examples are possible as well.

[0309] Two representative example battery vents are illustrated in Figures 20A-B and 21A-B. Turning first to Figures 20A-B, battery vent 1902 includes a cover 2002. Figure 20A shows battery vent 1902 in a sealed state, and Figure 20B shows battery vent 1902 in an open state. In this example, cover 2002 is a flexible cover that comprises three holes 2004 with each hole having a pressure vent 2006 positioned therein. Although three holes and corresponding pressure vents are shown, there may be fewer or more holes and corresponding pressure vents. When the threshold temperature is reached, the cover 2002 can melt away, thereby transitioning to the open state illustrated in Figure 20B.

[0310] Turning next to Figures 21A-B, battery vent 1902 includes cover 2102. Figure 21A shows battery vent 1902 in a sealed state, and Figure 2 IB shows battery vent 1902 in an open state. In this example, cover 2102 is a ceramic fibrous cover. When the threshold temperature isreached, cover 2102 can melt away, thereby transitioning to the open state illustrated in Figure 21B. Other example battery vents are possible as well.

[0311] In the examples of Figures 19-2 IB, the battery vents are positioned at the tops of the batteries. However, other battery-vent positions are possible including, for instance, on a side of the battery or at a bottom of the battery.B. Example Exhaust Locations

[0312] As discussed above with reference to Figures 15A-B, the battery system 400 is configured to be positioned in the battery bay 1510. Returning to Figure 19, the duct system 1904 is configured to exhaust gas to outside the battery bay 1510 when the one or more of the battery vents 1902 are in the open state. In this regard, the duct system 1904 may be configured to exhaust gas to various locations. As one possibility, the duct system 1904 is configured to exhaust gas to an environment external to the craft. In such an example, the one or more manifold exits 1910 may include an external vent configured to vent to the environment external to the craft.

[0313] As another possibility, the duct system 1904 is configured to exhaust gas to a bay of the craft different than the battery bay 1510. In such an example, the one or more manifold exits 1910 includes an internal vent configured to vent to the bay of the craft different than the battery bay 1510. Furthermore, in some examples, the duct system 1904 may be configured to vent to multiple locations. For instance, the one or more manifold exits 1910 may be configured to vent to the environment external to the craft as well as an internal vent configured to vent to bay of the craft different than the battery bay 1510. Other examples are possible as well.

[0314] Figure 22 illustrates an example in which the duct system 1904 is configured to vent to the environment external to the craft. In particular, ducting of the duct system 1904 routes to a position at a hull 102 of the craft, and an external vent 2202 at the interface of the hull 102 and manifold exit 1910 vents to external environment 2204.

[0315] Similar to the battery vents 1902 that are configured to transition from a sealed state to an open state at a threshold temperature, each of the one or more manifold exits may include a manifold vent configured to transition from a closed state to an open state at a threshold temperature. Any suitable threshold temperature is possible. In some examples, the threshold temperature at which the manifold vents transition from a closed state to an open state is the same as the threshold temperature at which the battery vents 1902 transition from a sealed state to an open state. However, in other examples, the manifold vent’s threshold temperature is different than the battery vent’ s threshold temperature. In one such example, the manifold vent’ s threshold temperature is less than the battery vent’s threshold temperature to account for decrease in temperature of the gas as it moves away from the battery. Further, similar to the battery vent 1902including one or more pressure vents that may seal the vent but allow for pressure release during normal operation of the battery, the manifold vent may be configured to (i) prevent material (e.g., external debris) from entering the manifold but (ii) allow airflow out of the manifold to regulate pressure that may occur during normal operation of the craft. Any suitable manifold vent are possible. In some examples, the manifold vent may be a GORE® Pressure Vents or a pop vent, among other possibilities. Still further, the manifold vent could be formed of any suitable material, including, for instance a thermoplastic material, among other possibilities.

[0316] Figure 23A illustrates an example manifold vent 2300 configured to transition from a closed state to an open state at a threshold temperature. The manifold vent 2300 may be configured to melt away at the threshold temperature, thereby transitioning from the closed state to the open state illustrated in Figure 23B.

[0317] Although the manifold vent 2300 is illustrated as being positioned at a manifold exit 1910, in some other examples, a manifold vent 2300 could be positioned within the manifold 1908 itself. For instance, a manifold vent could be positioned at any suitable upstream portion of the ducting. For instance, with reference to Figure 19, a manifold vent could be positioned at an internal location of the manifold 1908 such as an internal location 1920 (or any other suitable internal location of the manifold 1908). Placing the manifold vent 2300 within the manifold 1908 upstream of the manifold exit 1910 may help ensure that the vent is exposed to relatively higher temperature and that it would therefore be prone to melting away suitably in the event of a thermal runaway.

[0318] Within examples, the thermal-management system 1900 may include additional vents. For instance, the thermal-management system 1900 may include an external vent in a wall of the battery bay. Such a battery-bay vent may be configured to (i) prevent material (e.g., external debris) from entering the battery bay 1510 but (ii) allow airflow out of the battery bay 1510 to regulate pressure that may occur during normal operation of the craft 100.C. Example Ducting

[0319] The ducting 1906 arranged adjacent to the plurality of battery vents 1902 may take various forms. In general, the ducting arranged adjacent to the plurality of battery vents may be positioned at any suitable location proximate to the battery vents 1902. In an example, the ducting 1906 arranged adjacent to the plurality of battery vents 1902 includes a plurality of duct sections for batteries, where each battery of the battery system is associated with one of the duct sections of the plurality of duct sections. For instance, with reference to Figure 19, each battery 1002 is associated with its own duct section 1930. Further, Figure 24A shows close-up view of two batteries 1002 and their corresponding duct sections 1930. More particularly, Figure 24A showsa close-up view of a first battery 1002a and its associated duct section 1930a, as well as a second battery 1002b and its associated duct section 1930b.

[0320] In another example, the ducting 1906 arranged adjacent to the plurality of battery vents 1902 may include a plurality of duct sections where each duct section is associated with a set of batteries (e.g., 2 or more) of the battery system. For instance, with reference to Figure 24B, a single duct section 1930c is associated with a set of batteries including batteries 1002c and 1002d. In the example of Figure 24B, the battery vents 1902c-d of the batteries 1002c-d are positioned on the sides of the batteries 1002c-d. This side positioning of the battery vents helps to allow the single duct section 1930c to service multiple batteries. Further, in some examples where multiple batteries are associated with the same duct section, the positioning of the battery vents of those batteries may be offset from one another along the duct. For instance, with reference to Figure 24B, the vents 1902c and 1902d are offset from one another along the duct section 1930c. This offset positioning of the vents may help avoid a thermal runaway of one of the batteries 1002c or 1002d from causing thermal runaway of the other battery.

[0321] Beneficially, having duct sections 1930 associated with two or more batteries may reduce the number of duct tubes for the thermal-management system 1900, which in turn may help to reduce the weight of ducting (as well as of the craft 100 overall).

[0322] In some examples, rather than being ducting separate from the battery modules themselves, the ducting (or at least a portion of the ducting) of the duct system 1904 may be fully integrated with the battery modules themselves. This may beneficially require less space and fewer components than a separate physical ducting system.D. Example Expansion Joints

[0323] In some examples, when ducting of the thermal-management system 1900 is exposed to high temperatures, the ducting may expand. For instance, with hot gases running in the ducting of the duct system 1904, the ducting may heatup and thereby experience thermal expansion. In order to account for such potential thermal expansion of the ducting of the thermal-management system 1900, in some examples, the ducting 1906 arranged adjacent to the plurality of battery vents and / or the ducting of the manifold 1908 may include expansion joints.

[0324] In general, an expansion joint may include space between two duct sections. Further, the two duct sections may be configured to expand and thereby close the expansion joint at threshold temperature. The threshold temperature at which the expansion joint closes may be based on the material and thermal properties of the duct section. In some examples, the threshold temperature may be the same or similar to the threshold temperatures at which the battery vents transition from a sealed state to an open state at a threshold temperature and / or the threshold temperatures atwhich the manifold vent(s) transition from a closed state to an open state. At room temperature (during normal operation) there might be small gaps in the ducting, but then as the ducts heat up the expansion joints will close.

[0325] In some examples, the expansion joint may additionally include a sealant between the two duct sections. Any suitable sealant is possible including, for instance, a silicon seal, among other possibilities. The sealant may help to ensure that no water and / or debris enters the ducting via the expansion joints during normal operation of the craft 100.

[0326] Figure 25 illustrates an example expansion joint 2500 between a first duct section 1930d and a second duct section 1930e. Further, in this example, the expansion joint 2500 includes a seal 2502 (e.g., a silicon seal) that seals the space between the two duct sections 1930d-e. In the event of thermal expansion, the seal 2502 may melt away but the thermal expansion of the duct sections 1930d-e may close the expansion joint 2500.

[0327] Any suitable number of expansion joints are possible in the ducting of thermalmanagement system 1900. In an example, each respective duct section that is configured to connect to another duct section has an expansion joint between the respective duct section and the other duct section to which it is configured to connect. However, in other examples, fewer expansion joints are possible.

[0328] Beneficially, expansion joints may help to reduce or minimize weight of the ducting system, as well as reduce or minimize the number of parts for the ducting system, (e.g., they may help to avoid the use of additional clamps or wraps to secure duct sections together). The expansion joints may also beneficially help avoid failure of the ducting at increased temperatures (e.g., in some scenarios, thermal expansion may cause welds to pop, and utilizing expansion joints may reduce and / or eliminate the need for welds to join duct sections). Further, by being configured to close at increased temperatures (e.g., above the threshold temperature), the ducting is configured to seal and thereby effectively exhaust gas away from the battery system.E. Example Manifolds

[0329] Returning to Figure 19, the manifold 1908 may take various forms. In general, the manifold 1908 is configured to collect any gas that may flow through the ducting 1906 arranged adjacent to the plurality of battery vents 1902 and direct the gas to the one or more manifold exits 1910. In some examples, the manifold 1908 may include one or more manifold-aggregator sections connected to the ducting 1906 arranged adjacent to the plurality of battery vents 1902 and that serve to collect any gas that may flow through that ducting 1906.

[0330] Two examples of manifold-aggregator sections connected to the ducting 1906 are shown in Figures 26A-27B. In particular, Figure 26A illustrates an example in which manifold 1908includes a plurality of manifold-aggregator sections connected to the ducting 1906, and Figure 26B illustrates an example in which manifold 1908 includes a single manifold-aggregator section connected to the ducting 1906.

[0331] Turning first to Figure 26A, the ducting 1906 arranged adj acent to the plurality of battery vents 1902 includes a plurality of ducting levels 2602, 2604, and the manifold 1908 includes a plurality of manifold-aggregator sections 2606, 2608. Each ducting level is connected to a respective manifold-aggregator section. More particularly, ducting level 2602 is connected to manifold-aggregator section 2606, and ducting level 2604 is connected to manifold-aggregator section 2608. Further, the manifold-aggregator sections are connected via a manifold-connector section 2610.

[0332] Turning next to Figure 26B, the ducting 1906 arranged adj acent to the plurality of battery vents comprises ducting levels 2602, 2604, and these ducting levels are connected to a common manifold-aggregator section 2612.

[0333] Other forms of the manifold 1908 are possible as well. For instance, although the example manifolds depict the one or more manifold-aggregator sections being positioned on a single side of the thermal-management system 1900, in other examples, each side of the thermalmanagement system 1900 may include a manifold-aggregator section(s). Other examples are possible as well.

[0334] In some examples of the duct system, the manifold connecting the ducting arranged adjacent to the plurality of battery vents is an optional aspect of the duct system. For instance, the ducting arranged adjacent to the plurality of battery vents may be configured to vent to the battery bay without combining into a manifold. For instance, the ducting may have a plurality of different sections that each directly vent to outside the battery bay.

[0335] In some examples, the duct system does not combine all the ducting arranged adjacent to the plurality of battery vents together. In other examples, a manifold is included but only combines a portion of the ducting arranged adjacent to the plurality of battery vents together before venting. Other examples are possible as well.F. Example Dropouts

[0336] In some examples, the thermal -managem ent system 1900 may include one or more dropouts for collecting debris that may be within the thermal -management system 1900. In general, dropouts may be utilized at sections of the ducting of duct system 1904 that include a vertical rise in the ducting, so as to allow debris to “drop out” of the flow path of the gases.

[0337] The one or more dropouts may be positioned at any suitable location. As one possibility, the ducting 1906 arranged adjacent to the plurality of battery vents includes at least one of the oneor more dropouts for collecting debris. As another possibility, the manifold 1908 includes at least one of the one or more dropouts for collecting debris.

[0338] Example dropouts are illustrated in Figures 26A and 26C. With respect to Figure 26A, the manifold-connector section 2610 includes a single dropout 2620. As another example, the manifold path to the manifold exit 1910 may include one or more additional vertical rises. For instance, with reference to Figure 26C, the manifold 1908 include a first dropout 2630 at a vertical rise 2632, and a second dropout 2634 at a second vertical rise 2636.

[0339] The dropouts may be any suitable shape including, for instance, round, square, rectangular, among other possibilities.

[0340] Figure 27A illustrates an example collection of debris in a dropout and provides a representative illustration of how a dropout helps to prevent, reduce, or minimize a potential of a clog with the ducting. As shown in Figure 27A, exhaust gas 2702 and debris 2704 may flow through ducting 2706, and when the debris reaches the dropout 2708, debris may collect in dropout 2708. Exhaust gas 2702 may continue to flow up the vertical rise 2710. In contrast, Figure 27B illustrates example ducting without a dropout where debris 2704 is collecting at a bend in the ducting, and such a collection may risk clogging the ducting.G. Example Join Tubes

[0341] In practice, the battery system 400 and the thermal -managem ent system 1900 may need to be installed around other structural components of the craft (e.g., fixed structure components such as support beams of the craft 100). Thus, the ducting of the duct system 1904 of the thermalmanagement system 1900 may be configured to route around various structural components of the craft 100.

[0342] In order to accommodate routing around various structural components of the craft 100, the ducting may include join tubes, each of which is configured to connect two duct sections (e.g., two duct sections positioned near a structural component). In general, a join tube may form a path between two duct sections and that is not straight, so as to route the ducting around a structural element of the craft 100. In this regard, the join tube may include a decline section connected to an incline section, and these sections serve to route the ducting around a structural element. Any suitable shape of the join tube is possible, including, for instance, an arcuate shape or a V-shape, among other possibilities.

[0343] In some examples, in addition to providing the ability to connect two different duct sections that are unable to be connected via a straight line, the join tubes may also serve as a dropout for collecting debris.

[0344] An illustrative example of join tubes is described with reference to Figures 28A-B. In this example, the craft 100 includes a bulkhead 2802 that extends through the battery bay 1510. In turn, the ducting 1906 arranged adjacent to the plurality of battery vents includes a plurality of bulkhead-join tubes 2804 configured to (i) route the ducting arranged adjacent to the plurality of battery vents around the bulkhead and (ii) serve as dropouts between sets of batteries of the battery system. With reference to Figure 28B, bulk-head join tube 2804 connects duct section 2806 to duct section 2808. The bulkhead-join tube 2804a has an arcuate shape that includes a decline section 2810 (declining in the direction of flow towards to the manifold 1908) that connects to an incline section 2812 (inclining in the direction of flow towards the manifold 1908). Other example join tubes, as well as other example fixed structural components of the craft, are possible as well.H. Example Insulation

[0345] In some examples, all or at least a portion of the ducting of the thermal-management system 1900 may also be insulated. The thermal-management system 1900 may be positioned near other structural elements of the craft, and insulation may help to protect the other structural element of the craft (e.g., walls of the craft and / or structural support beam, among other possibilities).

[0346] Any suitable insulation for the ducting (or at least a portion of the ducting) of the thermalmanagement system 1900 is possible. In an example, the insulation includes hydrophobic insulation material which will still function even if the hull is exposed to water.

[0347] Further, in some examples, different portions of the ducting may be insulated with different insulation. For instance, ducting of the thermal-management system 1900 positioned near other structural elements of the craft may utilize a more robust insulation than other ducting of the thermal-management system 1900 that is not as close to other structural elements of the craft. For instance, a first portion of the duct system 1904 may include parts of the duct system that are positioned within a threshold distance of structural elements of the craft that are different than the battery system 400, and a second portion of the duct system 1904 may include parts of the duct system that are positioned greater than the threshold distance from the structural elements of the craft that are different than the battery system. The first portion of the duct system 1904 may be insulated with a first type of insulation and the second portion of the duct system may be insulated with a second type of insulation.

[0348] As one example, with respect to Figure 29A, a first portion 2902 includes include parts of the duct system 1904 that are positioned within a threshold distance of the structural elements of the deck beam and the bulkhead, whereas a second portion 2904 includes parts of the duct system 1904 that are positioned greater than the threshold distance from the structural elementsof the craft that are different than the battery system 400. Thus, the first portion 2902 may be insulated with a first type of insulation 2910 (see Figure 26B), and second portion 2904 may be insulated with a second type of insulation 2912 (see Figure 26C) (where the first type of insulation has a relatively higher thermal rating than the second type of insulation). As another example, third portion 2906 includes include parts of the duct system that are positioned within a threshold distance of the structural elements of the walls of the hull. This portion may also include the first type of insulation 2910 (or any other suitable insulation).I. Example Active Cooling

[0349] In some examples, the thermal -management system 1900 may also be configured to actively cool the battery system 400. In this regard, the thermal -management system 1900 may include one or more cooling-fluid lines (e.g., water lines) that are configured to cool the battery system 400.

[0350] The one or more cooling-fluid lines may take various forms. As one possibility, the cooling-fluid lines may be cooling-fluid lines that are separate from ducting of the duct system 1904. As another possibility, the cooling-fluid lines may be the ducting of the duct system 1904 or at least a sub portion of the ducting. Notably, by having the ducting of the duct system 1904 also serve as the cooling-fluid lines of the thermal-management system 1900, the weight of the thermal -managem ent system 1900 may be reduced or minimized. As yet another possibility, the one or more cooling-fluid lines may be integrated with the battery modules themselves. Other example cooling-fluid lines are possible as well.

[0351] In an example, the thermal-management system 1900 may have one or more fluid input ports through which cooling fluid (e.g., water) may be injected into the thermal-management system 1900. The fluid input ports may be coupled to the one or more cooling-fluid lines. Further, the fluid input ports may be located in any suitable location, one example of which is adjacent to the charging port(s) of the craft.

[0352] The manner in which the one or more cooling fluid lines are routed may help to reduce weight of the craft and / or complexity of parts, as well as provide improved temperature control across the battery system. In an example, optimal cooling routing from a heat transfer perspective may be a parallelized system such that each battery module experiences the same inlet temperature of coolant. However, in some scenarios, ensuring that each module experiences the same inlet temperature of coolant may not be feasible (e.g., due to packaging of the battery system), so the selected routing may balance between optimal cooling routing and packaging of the battery system.

[0353] The thermal-management system 1900 may serve to cool the battery system 400 via the one or more cooling-fluid lines at various time during operation. As one possibility, the thermalmanagement system 1900 may cool the battery system 400 prior to the charging of the battery system. In this regard, in order to charge the batteries of the battery system 400, the batteries need to reach a threshold low temperature (e.g., 45 degrees Celsius or below) before charging can commence. Notably, without active cooling, the battery system 400 would have to passively cool until the threshold low temperature is reached. However, the time required for passive cooling may impact turnaround time for the craft. Beneficially, the thermal -managem ent system 1900 being configured to actively cool the battery system 400 prior to charging may help to reduce the amount of time it takes for the battery system 400 to reach a sufficient temperature for charging (which in turn may help improve the turn-around time of the craft 100).

[0354] As another possibility, the thermal-management system 1900 may actively cool the battery system 400 during flight. For instance, in an example, the craft 100 may be configured to receive water (e.g., prior to take-off) and circulate that water through the one or more coolingfluid lines of the thermal-management system 1900, so as to actively cool the battery system 400 during flight. Such cooling may help to more effectively manage thermal conditions of the battery system 400 during operation. For instance, by actively cooling the battery system 400, the thermalmanagement system 1900 may make battery temperatures lower and / or more constant over the charge and discharge cycles of the batteries. By more effectively managing the thermal conditions, the disclosed thermal -management system 1900 may help to improve the cycle life of batteries of the battery system 400 of the craft 100.

[0355] As yet another possibility, the thermal -managem ent system 1900 may actively cool the battery system 400 before a mission and / or at take-off. For instance, in an example, the craft 100 may be configured to receive exterior fluids for a "thermal refresh" before mission and / or at takeoff. In an example, these fluids may heat up during such a thermal refresh and may be rendered no longer beneficial for taking heat away from the system. The thermal-management system 1900 may be configured to "flush" these warm fluids back out of the craft after the usefulness of the fluids has ended (e.g., in order to reduce weight). In an example, such a system may include a tank or other reservoir to add useful thermal mass with the ability to flush fluid out after take-off, thus taking some of the heat generated at take-off with it.

[0356] In some examples, the craft 100 may be configured such that (i) the hull itself may be used as a heat sink and (ii) water in the environment may be used to absorb heat from the battery system. For instance, the craft 100 may be configured to utilize the hull as a heat sink when the craft 100 is in the water (e.g., docked).

[0357] In some examples, the craft 100 may include one or more cooling-fluid lines that are adjacent to batteries of the battery system (e.g., on a first side of the cooling-fluid lines) and to the hull (e.g., on the other side of the cooling-fluid lines. Further, in some examples, these coolingfluid lines may be arranged such that they form part of the structure of the craft so as to enhance stiffness of the craft. As an illustrative example, Figure 30 illustrates a cross-section of a portion of the craft 100. Cooling-fluid lines 3002 are positioned between the battery system 400 and the hull 102. These cooling-fluid lines may not only help to cool the battery system (and facilitate heat transfer), but the cooling-fluid lines may also add to the stiffness of the hull 102. Further, as mentioned above, the hull 102 may be used as a heat sink and water in the environment may be used to absorb heat from the battery system, and these cooling lines may further enhance the capability of utilizing the hull as a heat sink. In an example, the cooling-fluid lines 3002 could be integrated into the hull 102 such that the cooling-fluid lines have direct exposure to outside air or water in more of a heat exchanger configuration. In such a scenario, conductive material may be added to a portion of the hull to locally enhance heat transfer in a specific area where the cooling lines 3002 are positioned.

[0358] In some examples, the thermal -management system 1900 may also be configured to flood the battery bay 1510 so as to actively cool the battery system 400. For instance, the thermalmanagement system 1900 may include a hatch in the hull of the craft that is configured to open in a situation in which (i) there is a thermal runaway of one or more batteries of the battery system 400 and (ii) a portion of the hull 102 is submerged in water (such that the hatch may allow water to enter the battery bay 1510 and flood the battery bay 1510). In this regard, the thermalmanagement system 1900 may include a sensor that is configured to detect a thermal runaway situation (e.g., by detecting a threshold high temperature in the battery bay), as well as a sensor configured to detect that the portion of the hull 102 is submerged in water. By flooding the battery bay 1510, the thermal -managem ent system 1900 may expose the entire battery system 400 or a portion thereof to water, so as to alleviate an emergency situation such as where there is a thermal runaway of one or more batteries of the battery system 400.

[0359] Other examples of actively cooling the battery system are possible as well.J. Example Moving System

[0360] In accordance with the present disclosure, a new moving system for moving batteries of a battery system of a craft is also provided. The moving system may be configured to move one or more batteries of a battery system of a craft, such as a battery pack of the battery system 400. In general, the moving system may be configured to support one or more batteries and move the one or more batteries both vertically and laterally within the craft. Further, the moving systemmay be configured to couple to one or more seat tracks of the craft, such that the moving system may run along the same rails that are used to mount seats (e.g., passenger seats) of the craft. The moving system may be utilized at any suitable time. For instance, the moving system may support installation of a battery system of a craft, as well as removing batteries from the craft (e.g., for repair of the battery system).

[0361] Within examples, the moving system includes (i) a battery holder configured to support one or more batteries and (ii) a hoist system configured to connect to the battery holder and comprising (a) a lift mechanism and (b) a translation mechanism. The lift mechanism is configured to raise and lower the battery holder (e.g., lower the battery holder vertically from a passenger bay to a battery bay or raise the battery older vertically from a battery bay to a passenger bay). Further, the translation mechanism is configured to couple to one or more seat tracks of the craft and translate along the one or more seat tracks, so as to move the hoist system laterally through the craft (e.g., laterally through the passenger bay). Still further, the battery holder and the hoist system may include connectors configured to secure the battery holder and hoist system to one another. For instance, the battery holder may include a battery-holder connector and the lift mechanism may include a corresponding lift-mechanism connector configured to connect to the battery-holder connector.

[0362] An example moving system is described with reference to Figures 31-34B. Turning first to Figure 31, an example moving system 3100 includes a battery holder 3102 and a hoist system 3104. The battery holder 3102 is configured to support battery pack 3106. Further, the hoist system 3104 is configured to connect to the battery holder 3102 and includes a lift mechanism 3108 and a translation mechanism 3110.

[0363] Battery holder 3102 is described in greater detail with reference to Figure 32. As illustrated in Figure 32, the battery holder 3102 comprises a frame 3202 and a battery -holder connector 3204. The frame 3202 is configured to support battery pack 3106 and also to be coupled to battery-holder connector 3204. Any suitable frame 3202 is possible. Within examples, the frame 3202 is structurally significant enough to securely hold the battery pack 3106 in place, yet designed to reduce or minimize weight (which may help to reduce or minimize the overall weight of the craft when the battery pack 3106 is installed in the craft). For instance, in the example of Figure 32, the frame 3202 takes the form of a lattice frame structure that helps to provide sufficient structure to support the weight of the battery pack but also reduces the weight of the battery holder 3102 (compared to, e.g., a more solid frame structure).

[0364] The battery-holder connector 3204 is configured to connect to the hoist system 3104. More particularly, the battery-holder connector 3204 is configured to connect to a correspondingconnector of the hoist system 3104. In the example of Figure 32, the battery-holder connector 3204 takes the form of an eye-hole that can be coupled to the hoist system 3104 such that the battery holder 3102 may be moved raised or lowered via the lift mechanism 3108 of the hoist system 3104. The battery holder-connector 3204 may take other forms as well.

[0365] In some examples, the battery-holder connector 3204 is non-removably connected to the frame 3202. In other examples, the battery-holder connector 3204 is removably connected to the frame 3202. In such examples where the battery-holder connector 3204 is removably connected to the frame 3202, the battery-holder connector 3204 may be removed after installation of the battery pack 3106 into the craft. The may also help to reduce or minimize the overall weight of the craft when the battery pack 3106 is installed in the craft.

[0366] The hoist system 3104 is described in greater detail with respect to Figure 33. Turning first to the lift mechanism 3108 and as illustrated in Figure 33, the lift mechanism 3108 includes a hoist 3302 coupled to a bar apparatus 3303. Hoist 3302 may take any of various forms including, for instance, a manual hoist (e.g., a manual chain hoist, a manual lever hoist, a manual rope hoist), an electric hoist (e.g., an electric chain hoist, an electric lever hoist, an electric rope hoist), a hydraulic hoist, a piston hoist, and / or a gear hoist, among other possibilities. The bar apparatus 3303 may take any of various forms. For instance, in the example of Figure 33, the bar apparatus includes a horizontal bar connected to a plurality of support legs. Other examples are possible as well.

[0367] As indicated above, the lift mechanism 3108 may include a lift-mechanism connector that is configured to connect to the battery-holder connector. The lift mechanism connector may take any suitable form including, for instance, a hook or carabiner-type connector, among other possibilities.

[0368] Turning next to the translation mechanism 3110, the translation mechanism 3110 may include one or more wheels configured to move along the rails of the seat tracks of the craft. For instance, as illustrated in Figure 33, the translation mechanism 3110 includes wheels 3304a-d positioned in outer seat tracks 3306 and 3308. Notably, batteries of a battery system of a craft are typically heavy, and due to the weight of the batteries it is beneficial to constrain the wheels to follow along the rails (as opposed to free wheels that can move in all directions).

[0369] As discussed above, the translation mechanism 3110 may help to move the batteries laterally through the craft. Returning to Figure 31, in an example, during installation of the battery system, the battery packs of the battery system may be stored on one or more pallets, such as pallet 3120. These pallets may then be loaded into the craft at a suitable position in the passenger bay 3126, such as position 3122 in the passenger bay 3126. In turn, the moving system 3100 may beused to move the battery packs (i) laterally from the position 3122 to a position above a hatch providing access to the battery bay 3124, and thereafter (ii) vertically into the battery bay 3124.

[0370] In the example of Figure 33, the translation mechanism 3110 is shown as coupled to the outer seat tracks 3306 and 3308. However, in other examples, the translation mechanism may be coupled to the inner seat tracks 3310 and 3312 and / or a combination of the inner and outer seat tracks.

[0371] In some examples, the translation mechanism 3110 includes one or more locks that allow the translation mechanism 3110 lock into the rails of the seat tracks to maintain position (e.g., to maintain position as the lift mechanism 3108 raises or lowers the battery holder 3102 from or into the battery bay 3124 and / or as a battery pack is hoisted off of the pallet 3120 at position 3122, among other possibilities). For instance, Figure 34A illustrates an example lock 3400 that is configured to move between a locked position and an unlocked position. The lock 3400 may take any of various forms. For instance, in an example, the lock 3400 includes a rod 3402 configured to move between (i) a locked position in which the lock is interested into a recess of the seat track 3308 and (ii) an unlocked position in which the rod is removed from the recess of the seat track 3308, thereby allowing the translation mechanism 3110 to translate along the seat tracks 3306 and 3308. In this regard, Figure 34b illustrates a cross-sectional view of the lock 3400 in the locked positioned in which the rod 3402 is positioned in recess 3404 of the seat track 3308. In another example, the lock may be a wheel lock that is configured to prevent rotation of the wheel 3304a. Other example locks are possible as well.IX. Example Clauses

[0372] The disclosure includes example embodiments in accordance with the following clauses:

[0373] Clause Al. A craft comprising: (i) hull; (ii) one or more wings coupled to the hull, wherein the one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings; (iii) a plurality of propellers arranged on the one or more wings, wherein the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboardside propellers; (iv) a plurality of propeller motors, wherein the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port-side-propeller motor is associated with a respective port-side propeller and each starboard-side-propeller motor is associated with a respective starboard-side propeller; and (v) a battery system comprising a plurality of sets of batteries, wherein each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propeller motors, wherein each respective set of propeller motors comprises (a) one or more of the port- side-propeller motors and (b) one or more of the starboard-side-propeller motors, and wherein, foreach respective set of propeller motors, the one or more starboard- si de propellers associated with the one or more of the starboard-side-propeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port-side-propeller motors.

[0374] Clause Al A. A craft comprising: (i) hull; (ii) one or more wings coupled to the hull, wherein the one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings; (iii) a plurality of propellers arranged on the one or more wings, wherein the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboardside propellers; (iv) a plurality of propeller motors, wherein the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port-side-propeller motor is associated with a respective port-side propeller and each starboard-side-propeller motor is associated with a respective starboard-side propeller; and (v) a battery system comprising a plurality of sets of batteries, wherein each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propeller motors, wherein each respective set of propeller motors comprises (a) one or more of the port- side-propeller motors and (b) one or more of the starboard-side-propeller motors.

[0375] Clause A2. The craft of clause Al or clause Al A, wherein each set of batteries comprises two or more batteries.

[0376] Clause A3. The craft of any one of clause Al to clause A2, further comprising: a plurality of control surfaces on the one or more wings, wherein at least a portion of each control surface is positioned within both (i) a coverage area associated with a first propeller associated with a first respective set of propeller motors and (ii) coverage area associated with a second propeller associated with a second respective set of propeller motors.

[0377] Clause A4. The craft of clause A3, wherein the plurality of control surfaces comprise at least one of (i) one or more flaps or (ii) one or more ailerons.

[0378] Clause A5. The craft of any one of clause Al to clause A4, wherein each respective set of propeller motors comprises three propeller motors.

[0379] Clause A6. The craft of any one of clause Al to clause A5, wherein, for each respective set of propeller motors, one of the one or more starboard- si de propellers and one of the one or more of the port-side-propellers are arranged at substantially the same distance from the hull, and the other one or more propellers associated with the respective set of propeller motors are arranged further from the hull.

[0380] Clause A7. The craft of clause A6, wherein, for a given set of propeller motors, the one of the one or more starboard- si de propellers and one of the one or more of the port-side-propellersare arranged at substantially the same distance from the hull comprise (i) a starboard-side propeller that is a first propeller from the hull on the starboard side and (ii) a port-side propeller that is a first propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a fifth propeller from the hull on the port side.

[0381] Clause A8. The craft of clause A6, wherein, for a given set of propeller motors, the one of the one or more starboard- si de propellers and one of the one or more of the port-side-propellers are arranged at substantially the same distance from the hull comprise (i) a starboard-side propeller that is a second propeller from the hull on the starboard side and (ii) a port-side propeller that is a second propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a fifth propeller from the hull on the starboard side.

[0382] Clause A9. The craft of clause A6, wherein, for a given set of propeller motors, the one of the one or more starboard- si de propellers and one of the one or more of the port-side-propellers are arranged at substantially the same distance from the hull comprise (i) a starboard-side propeller that is a third propeller from the hull on the starboard side and (ii) a port-side propeller that is a third propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a sixth propeller from the hull on the port side.

[0383] Clause A10. The craft of clause A6, wherein, for a given set of propeller motors, the one of the one or more starboard- si de propellers and one of the one or more of the port-side-propellers are arranged at substantially the same distance from the hull comprise (i) a starboard-side propeller that is a fourth propeller from the hull on the starboard side and (ii) a port-side propeller that is a fourth propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a sixth propeller from the hull on the starboard side.

[0384] Clause Al l. The craft of any one of clause Al to clause A6, wherein, for a given respective set of propeller motors, one propeller of the one or more starboard-side propellers and the one or more port-side propellers is arranged proximate to a wing tip.

[0385] Clause A12. The craft of clause Al l, wherein, for the respective given set of propeller motors, each of the other propellers of the one or more starboard-side propellers and the one or more port-side propellers is arranged between propellers associated with one or more different sets of propeller motors.

[0386] Clause A13. The craft of any one of clause Al to clause A12, wherein, for a given set of propeller motors, and for each respective propeller associated with the given set of propeller motors, a coverage area associated with the respective propeller overlaps at least in part with a coverage area of a propeller associated with a different set of propeller motors.

[0387] Clause A14. The craft of any one of clause Al to clause A13, wherein, for each respective set of batteries, batteries from the respective set of batteries are arranged within a respective set of battery subsystems of the battery system.

[0388] Clause A15. The craft of clause A14, wherein each battery subsystem of the respective set of battery subsystems comprises a plurality of battery packs, and wherein the batteries in each battery pack are connected in series.

[0389] Clause A16. The craft of clause A14 or clause A15, wherein the respective set of battery subsystems comprises two battery subsystems.

[0390] Clause A17. The craft of any one of clause A14 to clause A16, wherein each battery subsystem of the respective set of battery subsystems comprises a disconnect module configured to separate a first battery subset in the battery subsystem from a second battery subset in the battery subsystem.

[0391] Clause A18. The craft of clause A17, wherein each battery subsystem comprises a plurality of battery packs, and wherein the batteries in each respective battery pack are connected in series.

[0392] Clause Al 9. The craft of clause Al 8, wherein the first battery subset comprises batteries arranged in one pack of the plurality of packs, and wherein the second battery subset comprises batteries arranged in two packs of the plurality of packs.

[0393] Clause A20. The craft of any one of clause A14 to clause A19, wherein each battery subsystem further comprises a battery power management unit (BPMU) configured to control the battery subsystem.

[0394] Clause A21. The craft of clause A20, wherein the BPMU of a given battery subsystems is arranged on either a fore side or an aft side of the battery system, and wherein the disconnect module of a given battery subsystem is arranged on the other of the fore side or the aft side of the battery system.

[0395] Clause A22. The craft of clause A20, wherein the BPMUs of the battery subsystems are arranged on either a fore side or an aft side of the battery system, and wherein the disconnect modules of the battery subsystems are arranged on the other of the fore side or the aft side of the battery system.

[0396] Clause A23. The craft of any one of clause A14 to clause A22, further comprising: a plurality of buses, wherein each respective bus is connected to (i) one of the sets of battery subsystems and (ii) one of the respective sets of propeller motors from the plurality of propeller motors.

[0397] Clause A24. The craft of clause A23, wherein the respective bus is connected to the one of the sets of battery subsystems via a BPMU of the one of the sets of battery subsystems.

[0398] Clause A25. The craft of clause A24, wherein the craft comprises a charge port, and wherein the charge port is connected to at least a subset of the BPMUs.

[0399] Clause A26. The craft of clause A24, wherein the craft comprises a plurality of charge ports, and wherein each charge port is connected to a subset of the BPMUs.

[0400] Clause A27. The craft of any one of clause A23 to clause A26, wherein each respective bus is connected to the one of the sets of propeller motors via a respective set of wires having a respective total length, and wherein the respective total lengths of the sets of wires for each respective bus are substantially equal to one another.

[0401] Clause A28. The craft of any one of clause Al to clause A27, further comprising: a mounting system for the battery system, wherein the mounting system comprises: (i) a starboard stringer; (ii) a port stringer; (iii) a plurality of crossbeams arranged between the starboard and port stringers; and (iv) a plurality of hangar brackets for supporting the plurality of sets of batteries.

[0402] Clause A29. The craft of clause A28, wherein batteries from respective sets of batteries are arranged within a set of battery subsystems of the battery system, wherein each battery subsystem comprises a plurality of battery packs, and wherein the mounting system further comprises: a plurality of hangar brackets, wherein each hangar bracket is configured to hold one of the battery packs.

[0403] Clause A30. The craft of clause A29, wherein the mounting system further comprises: a plurality of stiffening brackets, wherein each stiffening bracket is configured to stiffen one of the battery packs.

[0404] Clause A31. The craft of any one of clause A28 to clause A30, wherein the battery system is positioned in the craft such that the center of gravity of the battery system is substantially aligned with a center of gravity of a remainder of the craft.

[0405] Clause A32. The craft of any one of clause Al to clause A27, wherein the hull comprises a battery bay, and wherein the battery bay comprises the battery system and a mounting system for the battery system.

[0406] Clause A33. The craft of clause A32, further comprising: (i) a passenger bay; and (ii) flooring separating the battery bay from the passenger bay, wherein the flooring comprises one ormore fire retardant materials to thereby provide a firewall between the battery bay and the passenger bay.

[0407] Clause A34. The craft of clause A33, wherein the flooring comprises a first hatch and a second hatch configured to provide access to the battery bay, wherein a first subset of the plurality of sets of batteries are accessible through the first hatch and a second subset of the plurality of sets of batteries are accessible through the second hatch.

[0408] Clause A35. The craft of clause A33 or clause A34, wherein the battery system comprises a plurality of battery power management units (BPMUs), and wherein the flooring further comprises one or more BPMU hatches configured to provide access to the BPMUs of the battery system.

[0409] Clause A36. The craft of any one of clause A32 to clause A35, wherein the craft further comprises: a duct system for the battery system, wherein the duct system is configured to exhaust gas from the battery bay to outside the battery bay.

[0410] Clause A37. The craft of clause A36, wherein the duct system is configured to exhaust gas from the battery bay to an environment external to the craft.

[0411] Clause A38. The craft of clause A36 or clause A37, wherein the duct system comprises: (i) ducting adjacent to each battery of the battery system; and (ii) a manifold configured to join the ducting adjacent to each battery.

[0412] Clause Bl. A battery system for a craft, wherein the craft comprises (i) hull, (ii) one or more wings coupled to the hull, wherein the one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings, (iii) a plurality of propellers arranged on the one or more wings, wherein the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboard- si de propellers, (iv) a plurality of propeller motors, wherein the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port-side-propeller motor is associated with a respective port-side propeller and each starboard-side-propeller motor is associated with a respective starboard-side propeller, and wherein the battery system comprises: a plurality of sets of batteries, wherein each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propeller motors, wherein each respective set of propeller motors comprises (a) one or more of the port-side-propeller motors and (b) one or more of the starboard-side-propeller motors, and wherein, for each respective set of propeller motors, the one or more starboard-side propellers associated with the one or more of the starboard-side-propeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port-side-propeller motors.

[0413] Clause BIA. A battery system for a craft, wherein the craft comprises (i) hull, (ii) one or more wings coupled to the hull, wherein the one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings, (iii) a plurality of propellers arranged on the one or more wings, wherein the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboard- si de propellers, (iv) a plurality of propeller motors, wherein the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port-side-propeller motor is associated with a respective port-side propeller and each starboard-side-propeller motor is associated with a respective starboard-side propeller, and wherein the battery system comprises: a plurality of sets of batteries, wherein each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propeller motors, wherein each respective set of propeller motors comprises (a) one or more of the port-side-propeller motors and (b) one or more of the starboard-side-propeller motors.

[0414] Clause B2. The battery system of clause Bl or clause BIA, wherein each set of batteries comprises two or more batteries.

[0415] Clause B3. The battery system of any one of clause Bl to clause B2, wherein the craft further comprises a plurality of control surfaces on the one or more wings, and wherein at least a portion of each control surface is positioned within both (i) a coverage area associated with a first propeller associated with a first respective set of propeller motors and (ii) coverage area associated with a second propeller associated with a second respective set of propeller motors.

[0416] Clause B4. The battery system of clause B3, wherein the plurality of control surfaces comprise at least one of (i) one or more flaps or (ii) one or more ailerons.

[0417] Clause B5. The battery system of any one of clause Bl to clause B4, wherein each respective set of propeller motors comprises three propeller motors.

[0418] Clause B6. The battery system of any one of clause Bl to clause B5, wherein, for each respective set of propeller motors, one of the one or more starboard- si de propellers and one of the one or more of the port-side-propellers are arranged at substantially the same distance from the hull, and the other one or more propellers associated with the respective set of propeller motors are arranged further from the hull.

[0419] Clause B7. The battery system of clause B6, wherein, for a given set of propeller motors, the one of the one or more starboard-side propellers and one of the one or more of the port-side- propellers are arranged at substantially the same distance from the hull comprise (i) a starboardside propeller that is a first propeller from the hull on the starboard side and (ii) a port-side propeller that is a first propeller from the hull on the port side, and wherein the other one or morepropellers associated with the respective set of propeller motors comprise a fifth propeller from the hull on the port side.

[0420] Clause B8. The battery system of clause B6, wherein, for a given set of propeller motors, the one of the one or more starboard-side propellers and one of the one or more of the port-side- propellers are arranged at substantially the same distance from the hull comprise (i) a starboardside propeller that is a second propeller from the hull on the starboard side and (ii) a port-side propeller that is a second propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a fifth propeller from the hull on the starboard side.

[0421] Clause B9. The battery system of clause B6, wherein, for a given set of propeller motors, the one of the one or more starboard-side propellers and one of the one or more of the port-side- propellers are arranged at substantially the same distance from the hull comprise (i) a starboardside propeller that is a third propeller from the hull on the starboard side and (ii) a port-side propeller that is a third propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a sixth propeller from the hull on the port side.

[0422] Clause BIO. The battery system of clause B6, wherein, for a given set of propeller motors, the one of the one or more starboard-side propellers and one of the one or more of the port-side- propellers are arranged at substantially the same distance from the hull comprise (i) a starboardside propeller that is a fourth propeller from the hull on the starboard side and (ii) a port-side propeller that is a fourth propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a sixth propeller from the hull on the starboard side.

[0423] Clause Bl l. The battery system of any one of clause Bl to clause B6, wherein, for a given respective set of propeller motors, one propeller of the one or more starboard- si de propellers and the one or more port-side propellers is arranged proximate to a wing tip.

[0424] Clause B12. The battery system of clause Bl l, wherein, for the respective given set of propeller motors, each of the other propellers of the one or more starboard- si de propellers and the one or more port-side propellers is arranged between propellers associated with one or more different sets of propeller motors.

[0425] Clause B13. The battery system of any one of clause Bl to clause Bl 2, wherein, for a given set of propeller motors, and for each respective propeller associated with the given set of propeller motors, a coverage area associated with the respective propeller overlaps at least in part with a coverage area of a propeller associated with a different set of propeller motors.

[0426] Clause B14. The battery system of any one of clause Bl to clause B 13, wherein, for each respective set of batteries, batteries from the respective set of batteries are arranged within a respective set of battery subsystems of the battery system.

[0427] Clause B15. The battery system of clause B14, wherein each battery subsystem of the respective set of battery subsystems comprises a plurality of battery packs, and wherein the batteries in each battery pack are connected in series.

[0428] Clause B16. The battery system of clause B14 or clause B15, wherein the respective set of battery subsystems comprises two battery subsystems.

[0429] Clause B17. The battery system of any one of clause B14 to clause B16, wherein each battery subsystem of the respective set of battery subsystems comprises a disconnect module configured to separate a first battery subset in the battery subsystem from a second battery subset in the battery subsystem.

[0430] Clause B18. The battery system of clause B17, wherein each battery subsystem comprises a plurality of battery packs, and wherein the batteries in each respective battery pack are connected in series.

[0431] Clause B 19. The battery system of clause B 18, wherein the first battery subset comprises batteries arranged in one pack of the plurality of packs, and wherein the second battery subset comprises batteries arranged in two packs of the plurality of packs.

[0432] Clause B20. The battery system of any one of clause B14 to clause B19, wherein each battery subsystem further comprises a battery power management unit (BPMU) configured to control the battery subsystem.

[0433] Clause B21. The battery system of clause B20, wherein the BPMU of a given battery subsystems is arranged on either a fore side or an aft side of the battery system, and wherein the disconnect module of a given battery subsystem is arranged on the other of the fore side or the aft side of the battery system.

[0434] Clause B22. The battery system of clause B20, wherein the BPMUs of the battery subsystems are arranged on either a fore side or an aft side of the battery system, and wherein the disconnect modules of the battery subsystems are arranged on the other of the fore side or the aft side of the battery system.

[0435] Clause B23. The battery system of any one of clause B14 to clause B22, further comprising: a plurality of buses, wherein each respective bus is connected to (i) one of the sets of battery subsystems and (ii) one of the respective sets of propeller motors from the plurality of propeller motors.

[0436] Clause B24. The battery system of clause B23, wherein the respective bus is connected to the one of the sets of battery subsystems via a BPMU of the one of the sets of battery subsystems.

[0437] Clause B25. The battery system of clause B24, wherein the craft comprises a charge port, and wherein the charge port is connected to at least a subset of the BPMUs.

[0438] Clause B26. The battery system of clause B24, wherein the craft comprises a plurality of charge ports, and wherein each charge port is connected to a subset of the BPMUs.

[0439] Clause B27. The battery system of any one of clause B23 to clause B26, wherein each respective bus is connected to the one of the sets of propeller motors via a respective set of wires having a respective total length, and wherein the respective total lengths of the sets of wires for each respective bus are substantially equal to one another.

[0440] Clause Cl . A mounting system for a battery system, the mounting system comprising: (i) a starboard stringer; (ii) a port stringer; (iii) a plurality of crossbeams arranged between the starboard and port stringers; and (iv) a plurality of hangar brackets for supporting a plurality of sets of batteries of the battery system.

[0441] Clause C2. The mounting system of clause Cl, wherein batteries from respective sets of batteries are arranged within a set of battery subsystems of the battery system, wherein each battery subsystem comprises a plurality of battery packs, and wherein the mounting system further comprises: a plurality of hangar brackets, wherein each hangar bracket is configured to hold one of the battery packs.

[0442] Clause C3. The mounting system of clause C2, wherein the mounting system further comprises: a plurality of stiffening brackets, wherein each stiffening bracket is configured to stiffen one of the battery packs.

[0443] Clause DI . A thermal -managem ent system for a battery system of a craft, wherein the battery system comprises a plurality of batteries, the thermal-management system comprising: (i) a plurality of battery vents, wherein each battery vent is (a) coupled to a respective battery of the battery system and (b) configured to transition from a sealed state to an open state at a threshold temperature; and (ii) a duct system comprising: (a) ducting arranged adjacent to the plurality of battery vents; and (b) a manifold (1) connecting the ducting arranged adjacent to the plurality of battery vents and (2) comprising one or more manifold exits, wherein the duct system is configured to exhaust gas away from the battery system when one or more of the battery vents are in the open state.

[0444] Clause D2. The thermal-management system of clause DI, wherein each battery vent is configured to transition from the sealed state to the open state at a same threshold temperature.

[0445] Clause D3. The thermal-management system of clause DI or clause D2, wherein each battery vent comprises a cover configured to (i) substantially prevent material from entering the battery vent and (ii) allow airflow out of the battery vent to regulate pressure during operation of the battery associated with the battery vent.

[0446] Clause D4. The thermal-management system of clause D3, wherein the cover comprises material configured to melt at the threshold temperature.

[0447] Clause D5. The thermal-management system of clause D3 or clause D4, wherein the cover comprises a flexible cover having one or more holes, and wherein each of the one or more holes comprises a respective pressure vent positioned therein.

[0448] Clause D6. The thermal-management system of clause D5 wherein at least one of the flexible cover and the pressure vents comprises thermoplastic polyurethane (TPU) material.

[0449] Clause D7. The thermal-management system of clause D3 or clause D4, wherein the cover comprises a ceramic fibrous cover.

[0450] Clause D8. The thermal-management system of any one of clause DI to D7, wherein the battery system is configured to be positioned in a battery bay of the craft, and wherein the duct system is configured to exhaust gas to outside the battery bay when the one or more of the battery vents are in the open state.

[0451] Clause D9. The thermal-management system of clause D8, wherein each of the one or more manifold exits comprises a manifold vent configured to transition from a closed state to an open state at a second threshold temperature.

[0452] Clause D10. The thermal-management system of clause D8 or D9, wherein the duct system is configured to exhaust gas to an environment external to the craft.

[0453] Clause Dl l. The thermal-management system of clause D10, wherein the one or more manifold exits comprises an external vent configured to vent to the environment external to the craft.

[0454] Clause D12. The thermal-management system of any one of clauses D8 to clause Dl l, wherein the duct system is configured to exhaust gas to a bay of the craft different than the battery bay.

[0455] Clause D13. The thermal-management system of clause DI 2, wherein the one or more manifold exits comprises an internal vent configured to vent to the bay of the craft.

[0456] Clause D14. The thermal-management system of any one of clause DI to clause D13, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of duct sections for batteries, and wherein each battery of the battery system is associated with one of the duct sections of the plurality of duct sections.

[0457] Clause DI 5. The thermal-management system of any one of clauses DI to clause DI 3, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of duct sections for batteries, and wherein each duct section is associated with a set of batteries of the battery system.

[0458] Clause D16. The thermal-management system of clause D14 or clause D15, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of expansion joints, wherein each respective expansion joint is positioned between two duct sections of the plurality of duct sections.

[0459] Clause D17. The thermal-management system of clause D16, wherein the respective expansion joint comprises space between the two duct sections, and wherein the two duct sections are configured to expand and thereby close the respective expansion joint at a third threshold temperature.

[0460] Clause D18. The thermal-management system of clause D16 or clause D17, wherein each of one or more of the expansion joints comprises sealant between the two duct sections.

[0461] Clause DI 9. The thermal-management system of any one of clause DI to clause DI 8, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, wherein the manifold comprises a plurality of manifold-aggregator sections, wherein each ducting level is connected to a respective manifold-aggregator section, and wherein the manifold-aggregator sections are connected via one or more manifold-connector sections.

[0462] Clause D20. The thermal-management system of any one of clause DI to clause DI 8, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, and wherein the ducting levels are connected to a common manifold-aggregator section.

[0463] Clause D21. The thermal-management system of any one of clause DI to clause D20, wherein the duct system comprises one or more dropouts for collecting debris.

[0464] Clause D22. The thermal-management system of clause D21, wherein the ducting arranged adjacent to the plurality of battery vents comprises at least one of the one or more dropouts for collecting debris.

[0465] Clause D23. The thermal-management system of clause D21 or clause D22, wherein the manifold comprises at least one of the one or more dropouts for collecting debris.

[0466] Clause D24. The thermal-management system of any one of clause DI to clause D23, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, wherein the manifold comprises a plurality of manifold-aggregator sections, wherein each ducting level connects to a respective manifold-aggregator section, and wherein themanifold-aggregator sections are connected via one or more manifold-connector sections, and wherein the one or more manifold-connector sections comprise at least one of the one or more dropouts for collecting debris.

[0467] Clause D25. The thermal-management system of any one of clause DI to clause D24, the ducting arranged adjacent to the plurality of battery vents comprises a plurality of join tubes configured to connect two duct sections, wherein the join tubes form a path between the two duct sections that is not straight.

[0468] Clause D26. The thermal-management system of clause D25, wherein each join tube comprises a decline section connected to an incline section.

[0469] Clause D27. The thermal-management system of clause D25 or clause D26, wherein each join tube comprises an arcuate shape.

[0470] Clause D28. The thermal-management system of any one of clause D25 to clause D27, wherein the craft comprises a bulkhead extending through a battery bay of the craft, and wherein the plurality of join tubes comprise a plurality of bulkhead-join tubes configured to (i) route the ducting arranged adjacent to the plurality of battery vents around the bulkhead and (ii) serve as dropouts between sets of batteries of the battery system.

[0471] Clause D29. The thermal-management system of any one of clause DI to clause D28, wherein tubes of the ducting arranged adjacent to the plurality of battery vents and tubes of the manifold are insulated.

[0472] Clause D30. The thermal-management system of clause D29, wherein a first portion of the duct system is insulated with a first type of insulation and a second portion of the duct system is insulated with a second type of insulation, wherein the first portion comprises parts of the duct system that are positioned within a threshold distance of structural elements of the craft that are different than the battery system, and wherein the second portion comprises parts of the duct system that are positioned greater than the threshold distance from the structural elements of the craft that are different than the battery system.

[0473] Clause El . A craft comprising: a battery system comprising a plurality of batteries; and a thermal-management system comprising: (i) a plurality of battery vents, wherein each battery vent is (a) coupled to a respective battery of the battery system and (b) configured to transition from a sealed state to an open state at a threshold temperature; and (ii) a duct system comprising: (a) ducting arranged adjacent to the plurality of battery vents; and (b) a manifold (1) connecting the ducting arranged adjacent to the plurality of battery vents and (2) comprising one or more manifold exits, wherein the duct system is configured to exhaust gas away from the battery system when one or more of the battery vents are in the open state.

[0474] Clause E2. The craft of clause El, wherein each battery vent is configured to transition from the sealed state to the open state at a same threshold temperature.

[0475] Clause E3. The craft of clause El or clause E2, wherein each battery vent comprises a cover configured to (i) substantially prevent material from entering the battery vent and (ii) allow airflow out of the battery vent to regulate pressure during operation of the battery associated with the battery vent.

[0476] Clause E4. The craft of clause E3, wherein the cover comprises material configured to melt at the threshold temperature.

[0477] Clause E5. The craft of clause E3 or clause E4, wherein the cover comprises a flexible cover having one or more holes, and wherein each of the one or more holes comprises a respective pressure vent positioned therein.

[0478] Clause E6. The craft of clause E5 wherein at least one of the flexible cover and the pressure vents comprises thermoplastic polyurethane (TPU) material.

[0479] Clause E7. The craft of clause E3 or clause E4, wherein the cover comprises a ceramic fibrous cover.

[0480] Clause E8. The craft of any one of clause El to E7, wherein the battery system is configured to be positioned in a battery bay of the craft, and wherein the duct system is configured to exhaust gas to outside the battery bay when the one or more of the battery vents are in the open state.

[0481] Clause E9. The craft of clause E8, wherein each of the one or more manifold exits comprises a manifold vent configured to transition from a closed state to an open state at a second threshold temperature.

[0482] Clause E10. The craft of clause E8 or E9, wherein the duct system is configured to exhaust gas to an environment external to the craft.

[0483] Clause El 1. The craft of clause E10, wherein the one or more manifold exits comprises an external vent configured to vent to the environment external to the craft.

[0484] Clause E12. The craft of any one of clauses E8 to clause El l, wherein the duct system is configured to exhaust gas to a bay of the craft different than the battery bay.

[0485] Clause E13. The craft of clause E12, wherein the one or more manifold exits comprises an internal vent configured to vent to the bay of the craft.

[0486] Clause E14. The craft of any one of clause El to clause E13, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of duct sections for batteries, and wherein each battery of the battery system is associated with one of the duct sections of the plurality of duct sections.

[0487] Clause E15. The craft of any one of clauses El to clause E13, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of duct sections for batteries, and wherein each duct section is associated with a set of batteries of the battery system.

[0488] Clause E16. The craft of clause E14 or clause E15, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of expansion joints, wherein each respective expansion joint is positioned between two duct sections of the plurality of duct sections.

[0489] Clause E17. The craft of clause E16, wherein the respective expansion joint comprises space between the two duct sections, and wherein the two duct sections are configured to expand and thereby close the respective expansion joint at a third threshold temperature.

[0490] Clause E18. The craft of clause E16 or clause E17, wherein each of one or more of the expansion joints comprises sealant between the two duct sections.

[0491] Clause E19. The craft of any one of clause El to clause E18, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, wherein the manifold comprises a plurality of manifold-aggregator sections, wherein each ducting level is connected to a respective manifold-aggregator section, and wherein the manifold-aggregator sections are connected via one or more manifold-connector sections.

[0492] Clause E20. The craft of any one of clause El to clause El 8, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, and wherein the ducting levels are connected to a common manifold-aggregator section.

[0493] Clause E21. The craft of any one of clause El to clause E20, wherein the duct system comprises one or more dropouts for collecting debris.

[0494] Clause E22. The craft of clause E21, wherein the ducting arranged adjacent to the plurality of battery vents comprises at least one of the one or more dropouts for collecting debris.

[0495] Clause E23. The craft of clause E21 or clause E22, wherein the manifold comprises at least one of the one or more dropouts for collecting debris.

[0496] Clause E24. The craft of any one of clause El to clause E23, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, wherein the manifold comprises a plurality of manifold-aggregator sections, wherein each ducting level connects to a respective manifold-aggregator section, and wherein the manifold-aggregator sections are connected via one or more manifold-connector sections, and wherein the one or more manifold-connector sections comprise at least one of the one or more dropouts for collecting debris.

[0497] Clause E25. The craft of any one of clause El to clause D24, the ducting arranged adjacent to the plurality of battery vents comprises a plurality of join tubes configured to connecttwo duct sections, wherein the join tubes form a path between the two duct sections that is not straight.

[0498] Clause E26. The craft of clause E25, wherein each join tube comprises a decline section connected to an incline section.

[0499] Clause E27. The craft of clause E25 or clause E26, wherein each join tube comprises an arcuate shape.

[0500] Clause E28. The craft of any one of clause E25 to clause E27, wherein the craft comprises a bulkhead extending through a battery bay of the craft, and wherein the plurality of join tubes comprise a plurality of bulkhead -join tubes configured to (i) route the ducting arranged adjacent to the plurality of battery vents around the bulkhead and (ii) serve as dropouts between sets of batteries of the battery system.

[0501] Clause E29. The craft of any one of clause El to clause E28, wherein tubes of the ducting arranged adjacent to the plurality of battery vents and tubes of the manifold are insulated.

[0502] Clause E30. The craft of clause E29, wherein a first portion of the duct system is insulated with a first type of insulation and a second portion of the duct system is insulated with a second type of insulation, wherein the first portion comprises parts of the duct system that are positioned within a threshold distance of structural elements of the craft that are different than the battery system, and wherein the second portion comprises parts of the duct system that are positioned greater than the threshold distance from the structural elements of the craft that are different than the battery system.

[0503] Clause Fl. A duct system for a thermal -management system for a battery system of a craft, wherein the battery system comprises a plurality of batteries, and wherein the thermalmanagement system comprises a plurality of battery vents, the duct system comprising: (a) ducting arranged adjacent to the plurality of battery vents; and (b) a manifold (1) connecting the ducting arranged adjacent to the plurality of battery vents and (2) comprising one or more manifold exits, wherein the duct system is configured to exhaust gas away from the battery system when one or more of the battery vents are in an open state.

[0504] Clause F2. The duct system of clause Fl, wherein the battery system is configured to be positioned in a battery bay of the craft, and wherein the duct system is configured to exhaust gas to outside the battery bay when the one or more of the battery vents are in the open state.

[0505] Clause F3. The duct system of clause F2, wherein each of the one or more manifold exits comprises a manifold vent configured to transition from a closed state to an open state at a second threshold temperature.

[0506] Clause F4. The duct system of clause F2 or F3, wherein the duct system is configured to exhaust gas to an environment external to the craft.

[0507] Clause F5. The duct system of clause F4, wherein the one or more manifold exits comprises an external vent configured to vent to the environment external to the craft.

[0508] Clause F6. The duct system of any one of clauses F2 to clause F5, wherein the duct system is configured to exhaust gas to a bay of the craft different than the battery bay.

[0509] Clause F7. The duct system of clause F6, wherein the one or more manifold exits comprises an internal vent configured to vent to the bay of the craft.

[0510] Clause F8. The duct system of any one of clause Fl to clause F7, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of duct sections for batteries, and wherein each battery of the battery system is associated with one of the duct sections of the plurality of duct sections.

[0511] Clause F9. The duct system of any one of clauses Fl to clause F7, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of duct sections for batteries, and wherein each duct section is associated with a set of batteries of the battery system.

[0512] Clause F10. The duct system of clause F8 or clause F9, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of expansion joints, wherein each respective expansion joint is positioned between two duct sections of the plurality of duct sections.

[0513] Clause Fl 1. The duct system of clause F10, wherein the respective expansion joint comprises space between the two duct sections, and wherein the two duct sections are configured to expand and thereby close the respective expansion joint at a third threshold temperature.

[0514] Clause F12. The duct system of clause F10 or clause Fl 1, wherein each of one or more of the expansion joints comprises sealant between the two duct sections.

[0515] Clause F13. The duct system of any one of clause Fl to clause Fl 2, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, wherein the manifold comprises a plurality of manifold-aggregator sections, wherein each ducting level is connected to a respective manifold-aggregator section, and wherein the manifold-aggregator sections are connected via one or more manifold-connector sections.

[0516] Clause F14. The duct system of any one of clause Fl to clause F 12, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, and wherein the ducting levels are connected to a common manifold-aggregator section.

[0517] Clause Fl 5. The duct system of any one of clause Fl to clause Fl 4, wherein the duct system comprises one or more dropouts for collecting debris.

[0518] Clause Fl 6. The duct system of clause Fl 5, wherein the ducting arranged adjacent to the plurality of battery vents comprises at least one of the one or more dropouts for collecting debris.

[0519] Clause F17. The duct system of clause F15 or clause F16, wherein the manifold comprises at least one of the one or more dropouts for collecting debris.

[0520] Clause Fl 8. The duct system of any one of clause Fl to clause Fl 7, wherein the ducting arranged adjacent to the plurality of battery vents comprises a plurality of ducting levels, wherein the manifold comprises a plurality of manifold-aggregator sections, wherein each ducting level connects to a respective manifold-aggregator section, and wherein the manifold-aggregator sections are connected via one or more manifold-connector sections, and wherein the one or more manifold-connector sections comprise at least one of the one or more dropouts for collecting debris.

[0521] Clause F 19. The duct system of any one of clause F 1 to clause F 18, the ducting arranged adjacent to the plurality of battery vents comprises a plurality of join tubes configured to connect two duct sections, wherein the join tubes form a path between the two duct sections that is not straight.

[0522] Clause F20. The duct system of clause Fl 9, wherein each join tube comprises a decline section connected to an incline section.

[0523] Clause F21. The duct system of clause F19 or clause F20, wherein each join tube comprises an arcuate shape.

[0524] Clause F22. The duct system of any one of clause F19 to clause F21, wherein the craft comprises a bulkhead extending through a battery bay of the craft, and wherein the plurality of join tubes comprise a plurality of bulkhead -join tubes configured to (i) route the ducting arranged adjacent to the plurality of battery vents around the bulkhead and (ii) serve as dropouts between sets of batteries of the battery system.

[0525] Clause F23. The duct system of any one of clause Fl to clause F22, wherein tubes of the ducting arranged adjacent to the plurality of battery vents and tubes of the manifold are insulated.

[0526] Clause F24. The duct system of clause F23, wherein a first portion of the duct system is insulated with a first type of insulation and a second portion of the duct system is insulated with a second type of insulation, wherein the first portion comprises parts of the duct system that are positioned within a threshold distance of structural elements of the craft that are different than the battery system, and wherein the second portion comprises parts of the duct system that arepositioned greater than the threshold distance from the structural elements of the craft that are different than the battery system.

[0527] Clause G1. A moving system for moving batteries of a battery system of a craft, the moving system comprising: (i) a battery holder configured to support one or more batteries; and (ii) a hoist system configured to connect to the battery holder and comprising (a) a lift mechanism configured to raise and lower battery holder and (b) a translation mechanism configured to couple to one or more seat tracks of the craft and translate along the one or more seat tracks, so as to move the hoist system through the craft.X. Conclusion

[0528] The above detailed description describes various features and functions of the disclosed craft and methods of operation with reference to the accompanying figures. While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

Claims

CLAIMS1. A craft comprising: a hull; one or more wings coupled to the hull, wherein the one or more wings comprise a port side of the one or more wings and a starboard side of the one or more wings; a plurality of propellers arranged on the one or more wings, wherein the plurality of propellers comprises a plurality of port-side propellers and a plurality of starboard-side propellers; a plurality of propeller motors, wherein the plurality of propeller motors comprises a plurality of port-side-propeller motors and a plurality of starboard side-propeller motors, wherein each port-side-propeller motor is associated with a respective port-side propeller and each starboard-side-propeller motor is associated with a respective starboard- si de propeller; and a battery system comprising a plurality of sets of batteries, wherein each set of batteries is configured to provide power to a respective set of propeller motors from the plurality of propeller motors, wherein each respective set of propeller motors comprises (i) one or more of the port- side-propeller motors and (ii) one or more of the starboard-side-propeller motors, and wherein, for each respective set of propeller motors, the one or more starboard-side propellers associated with the one or more of the starboard-side-propeller motors comprise a different number of propellers than the one or more port-side propellers associated with the one or more of the port- side-propeller motors.

2. The craft of claim 1, further comprising: a plurality of control surfaces on the one or more wings, wherein at least a portion of each control surface is positioned within both (i) a coverage area associated with a first propeller associated with a first respective set of propeller motors and (ii) a coverage area associated with a second propeller associated with a second respective set of propeller motors.

3. The craft of any preceding claim, wherein each respective set of propeller motors comprises three propeller motors.

4. The craft of any preceding claim, wherein, for each respective set of propeller motors, one of the one or more starboard- si de propellers and one of the one or more of the port-side-propellers are arranged at substantially the same distance from the hull, and the other one or more propellers associated with the respective set of propeller motors are arranged further from the hull.

5. The craft of claim 4, wherein, for a given set of propeller motors, the one of the one or more starboard- si de propellers and the one of the one or more of the port-side-propellers that are arranged at substantially the same distance from the hull comprise (i) a starboard- si de propeller that is a first propeller from the hull on the starboard side and (ii) a port-side propeller that is a first propeller from the hull on the port side, and wherein the other one or more propellers associated with the respective set of propeller motors comprise a second propeller from the hull on the port side.

6. The craft of any preceding claim, wherein, for a given respective set of propeller motors, one propeller of the one or more starboard- si de propellers and the one or more port-side propellers is arranged proximate to a wing tip.

7. The craft of claim 6, wherein, for the given respective set of propeller motors, each of the other propellers of the one or more starboard- si de propellers and the one or more port-side propellers is arranged between propellers associated with one or more different sets of propeller motors.

8. The craft of any preceding claim, wherein, for a given set of propeller motors, and for each respective propeller associated with the given set of propeller motors, a coverage area associated with the respective propeller overlaps at least in part with a coverage area of a propeller associated with a different set of propeller motors.

9. The craft of any preceding claim, wherein, for each respective set of batteries, batteries from the respective set of batteries are arranged within a respective set of battery subsystems of the battery system.

10. The craft of claim 9, wherein each battery subsystem of the respective set of battery subsystems comprises a plurality of battery packs, and wherein the batteries in each battery pack are connected in series.

11. The craft of claim 9 or 10, wherein each battery subsystem further comprises a battery power management unit (BPMU) configured to control the battery subsystem.

12. The craft of claim 9 or 10, further comprising:a plurality of buses, wherein each respective bus is connected to (i) one of the sets of battery subsystems and (ii) one of the respective sets of propeller motors from the plurality of propeller motors.

13. The craft of any preceding claim, wherein the hull comprises a battery bay, and wherein the battery bay comprises the battery system and a mounting system for the battery system.

14. The craft of claim 13, further comprising: a passenger bay; and flooring separating the battery bay from the passenger bay, wherein the flooring comprises one or more fire retardant materials to thereby provide a firewall between the battery bay and the passenger bay.

15. The craft of claim 13 or 14, further comprising: a duct system for the battery system, wherein the duct system is configured to exhaust gas from the battery bay to outside the battery bay.

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