Flame effect system for unmanned aerial vehicles

Abstract

A flame effect system for an unmanned aerial vehicle (UAV) includes a hopper configured to store powdered fuel, a propellant tank configured to store propellant, and a nozzle configured to discharge the powdered fuel into the atmosphere. Furthermore, the flame effect system includes a fluid path extending from the propellant tank to the nozzle. The hopper is fluidly connected to the fluid path at a junction between the propellant tank and the nozzle. The hopper is configured to allow the powdered fuel to flow into the fluid path, and the propellant tank is configured to discharge propellant through the fluid path to fluidize the powdered fuel within the fluid path and to drive the fluidized powdered fuel through the nozzle.

Description

[0001] Cross-reference to related applications This application claims priority and benefit to U.S. Provisional Application Serial No. 63 / 556,917, filed February 23, 2024, entitled “FLAME EFFECT SYSTEM FOR ANUNMANNED AERIAL VEHICLE”, which is incorporated herein by reference in its entirety. Background Technology

[0002] This disclosure generally relates to a flame effect system for unmanned aerial vehicles.

[0003] Some unmanned aerial vehicles (UAVs) (e.g., drones) include flame-launching systems that can be used to initiate controlled combustion for forest management. A flame-launching system may include a canister, pump, nozzle, and ignition system. The canister is configured to contain a liquid fuel (e.g., gasoline, kerosene, etc.). The pump drives the liquid fuel from the canister to the nozzle. The nozzle atomizes the liquid fuel, and the ignition system ignites the atomized fuel, thereby establishing a combustion reaction. To reduce the likelihood of fuel leakage in the event of an unexpected, forceful landing of the UAV, the flame-launching system may include a thick-walled canister and one or more valves configured to selectively prevent fuel from flowing out of the canister. Due to the thick-walled canister, valve(s), and pump, the flame-launching system can be quite heavy. Because of the weight of the flame-launching system, a UAV with a large lifting capacity may be used to support it. However, due to the costs associated with such a high-lift-capacity UAV and the costs associated with the thick-walled canister and valve(s) of the flame-launching system, UAVs with flame-launching systems may be prohibitively expensive for some applications. Summary of the Invention

[0004] The following outlines certain embodiments that are proportionate to the scope of the original claimed subject matter. These embodiments are not intended to limit the scope of the claimed subject matter, but are merely intended to provide a brief overview of the possible forms of the claimed subject matter. In practice, the claimed subject matter may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

[0005] In some embodiments, a flame effect system for an unmanned aerial vehicle includes a hopper configured to store powdered fuel, a propellant tank configured to store propellant, and a nozzle configured to discharge the powdered fuel into the atmosphere. Furthermore, the flame effect system includes a fluid path extending from the propellant tank to the nozzle. The hopper is fluidly connected to the fluid path at a junction between the propellant tank and the nozzle. The hopper is configured to allow the powdered fuel to flow into the fluid path, and the propellant tank is configured to discharge propellant through the fluid path to fluidize the powdered fuel within the fluid path and to drive the fluidized powdered fuel through the nozzle.

[0006] Furthermore, in some embodiments, an unmanned aerial vehicle includes a main body, at least one motor coupled to the main body, at least one propeller coupled to the at least one motor, a battery coupled to the main body and electrically coupled to the at least one motor, and a flame effect system coupled to the main body. The flame effect system includes a hopper configured to store powdered fuel, a propellant tank configured to store propellant, a nozzle configured to discharge the powdered fuel into the atmosphere, and a fluid path extending from the propellant tank to the nozzle. The hopper is fluidly coupled to the fluid path at a junction between the propellant tank and the nozzle. The hopper is configured such that the powdered fuel can flow into the fluid path, and the propellant tank is configured to discharge propellant through the fluid path to fluidize the powdered fuel within the fluid path and to drive the fluidized powdered fuel through the nozzle.

[0007] Additionally, in some embodiments, a flame effect system for an unmanned aerial vehicle includes a hopper configured to store powdered fuel, a propellant tank configured to store propellant, a nozzle configured to discharge the powdered fuel into the atmosphere, and a fluid path extending from the propellant tank to the nozzle. The hopper is fluidly connected to the fluid path at a junction between the propellant tank and the nozzle, and the hopper is configured to allow the powdered fuel to flow into the fluid path. The flame effect system also includes a valve disposed along the fluid path between the propellant tank and the junction. The valve is configured to selectively open to allow propellant flow through the fluid path to fluidize the powdered fuel within the fluid path and to drive the fluidized powdered fuel through the nozzle. Furthermore, the flame effect system includes an igniter positioned at or near the nozzle. The igniter is configured to activate to initiate a combustion reaction between the fluidized powdered fuel and atmospheric oxygen. Additionally, the flame effect system includes a controller communicatively connected to the valve and the igniter. The controller includes a memory and a processor, and is configured to command the valve to open and the igniter to activate to initiate the combustion reaction. Attached Figure Description

[0008] These and other features, aspects, and advantages of this disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein similar reference numerals denote similar parts throughout the drawings, wherein: Figure 1 This is a perspective view of an embodiment of an unmanned aerial vehicle (UAV) with a flame effect system; Figure 2 yes Figure 1 A schematic diagram of a UAV; and Figure 3 It is possible Figure 1 A schematic diagram of an embodiment of a flame effect system used in a UAV. Detailed Implementation

[0009] One or more specific embodiments of this disclosure will be described below. To provide a concise description of these embodiments, not all features of an actual implementation may be described in the specification. It should be recognized that, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which may vary from one implementation to another. Furthermore, it should be recognized that such development work may be complex and time-consuming, but will remain a routine task of design, manufacture, and production for those skilled in the art who benefit from this disclosure.

[0010] When describing elements of various embodiments of this disclosure, the articles “a,” “an,” “the,” and “described” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present besides those listed. Any examples of operating parameters and / or environmental conditions do not exclude other parameters / conditions for the disclosed embodiments.

[0011] Figure 1This is a perspective view of an embodiment of an unmanned aerial vehicle (UAV) 10 (e.g., a drone) with a flame effect system 12. As illustrated, the UAV 10 includes a body 14 and a plurality of motors 16 coupled to the body 14. In the illustrated embodiment, each motor 16 is coupled to the body 14 by a corresponding arm 18. However, in other embodiments, at least one motor (e.g., each motor) may be coupled to the body via any suitable structure (e.g., a frame, truss assembly, etc.). Furthermore, the UAV 10 includes a plurality of propellers 20 coupled to the motors 16. In the illustrated embodiment, each motor 16 is coupled to one propeller 20. However, in other embodiments, multiple propellers may be coupled to a single motor, and / or multiple motors may drive a single propeller. In the illustrated embodiment, the UAV 10 includes four motors 16 and four propellers 20. However, in other embodiments, the UAV may include more or fewer motors and / or more or fewer propellers.

[0012] As discussed in detail below, UAV 10 includes a battery electrically connected to and configured to supply power to motor 16. The battery may be connected to the body 14 (e.g., disposed within a cavity of the body, connected to an external surface of the body, etc.). UAV 10 includes a controller configured to control the motors 16, thereby controlling the movement of UAV 10. For example, in some embodiments, the controller may control the rotational speed of each motor 16, thereby controlling the height, attitude, and direction of movement of UAV 10.

[0013] As illustrated, the flame effect system 12 is coupled to the body 14 and is configured to selectively generate flame effect 22. As discussed in detail below, the flame effect system 12 includes a hopper configured to store powdered fuel (e.g., lycopodium powder, etc.) and a propellant tank configured to store propellant (e.g., carbon dioxide, etc.). The flame effect system 12 also includes a nozzle configured to discharge the powdered fuel into the atmosphere. Furthermore, the flame effect system 12 includes a fluid path extending from the propellant tank to the nozzle. The hopper is fluidly coupled to the fluid path at the junction between the propellant tank and the nozzle, and the hopper is configured such that the powdered fuel can flow into the fluid path under the influence of gravity. Additionally, the propellant tank is configured to discharge propellant through the fluid path to fluidize the powdered fuel and drive the powdered fuel through the nozzle. In some embodiments, the flame effect system 12 also includes an igniter positioned at or near the nozzle. The igniter is configured to activate to initiate a combustion reaction between powdered fuel and oxygen in the atmosphere, thereby generating flame effect 22.

[0014] While the illustrated embodiment shows a single flame effect system 12 for UAV 10, in other embodiments, the UAV may include multiple flame effect systems (e.g., 2, 3, 4, or more). For example, in some embodiments, the UAV may include one flame effect system configured to generate flame effects in a first direction (e.g., forward direction) and another flame effect system configured to generate flame effects in a second direction (e.g., backward direction). Furthermore, in some embodiments, the UAV may include multiple flame effect systems configured to generate multiple flame effects in a single direction.

[0015] The UAV 10 with the flame effect system 12 can be used as part of an aerial performance that combines UAV movement with flame effects. For example, multiple UAVs (each with a flame effect system) can be operated in a coordinated aerial performance. Because the flame effect system uses powdered fuel to generate the flame effect, the need for thick-walled tanks for storing liquid fuel (e.g., thick-walled tanks to reduce the possibility of fuel leakage in the event of an unexpected, forceful landing of the UAV) is avoided, and the weight of the flame effect system can be reduced (e.g., compared to a liquid fuel flame effect system), thereby reducing the size and cost of the UAV. Furthermore, if the UAV experiences an unexpected, forceful landing sufficient to cause the powdered fuel to leak onto the ground, the powdered fuel can be practically non-flammable (e.g., because a pile of powdered fuel on the ground may not receive enough oxygen for ignition).

[0016] Figure 2 yes Figure 1 A schematic diagram of UAV 10 is shown. As previously discussed, UAV 10 includes a plurality of motors 16 coupled to a body 14, and UAV 10 includes a plurality of propellers 20 coupled to the motors 16. The motors 16 are configured to drive the propellers 20 to rotate, thereby controlling the movement of UAV 10. In the illustrated embodiment, UAV 10 includes a battery 24 coupled to the body 14 and electrically coupled to the motors 16. The battery 24 is configured to provide power to the motors 16, thereby enabling the motors 16 to drive the propellers 20 to rotate. In some embodiments, the battery 24 is rechargeable, and the UAV includes an electrical connector configured to establish an electrical connection to a power source, thereby facilitating the recharging of the battery 24. Alternatively or additionally, the battery may be removable, thereby allowing an operator to replace the battery for continued operation of the UAV. As previously discussed, a flame effect system 12 is coupled to the body 14 and configured to generate flame effects.

[0017] In the illustrated embodiment, UAV 10 includes a controller 26 communicatively coupled to motor 16 and flame effect system 12. In some embodiments, controller 26 may be part of flame effect system 12. As illustrated, controller 26 is coupled to body 14 of UAV 10. For example, controller 26 may be disposed within a cavity of body 14, or controller 26 may be coupled to an external surface of body 14. As discussed in detail below, controller 26 is configured to control motor 16 to control movement of UAV 10, and to control flame effect system 12 to control flame effects. In some embodiments, controller 26 is an electronic controller having electrical circuitry configured to control motor 16 and flame effect system 12. In the illustrated embodiment, controller 26 includes a processor, such as microprocessor 28 illustrated. Controller 26 may also include one or more storage devices, such as memory device 30 illustrated, and / or other suitable components. Processor 28 may be used to run software, such as software for controlling motor 16, flame effect system 12, etc. In addition, processor 28 may include multiple microprocessors, one or more "general purpose" microprocessors, one or more application-specific microprocessors, one or more application-specific integrated circuits (ASICs), one or more reduced instruction set (RISC) processors, or some combination thereof.

[0018] Memory device 30 may include volatile memory such as random access memory (RAM) and / or non-volatile memory such as read-only memory (ROM). Memory device 30 may store a variety of information and may be used for a variety of purposes. For example, memory device 30 may store processor-executable instructions (e.g., firmware or software) for execution by processor 28, such as instructions for controlling motor 16, flame effect system 12, etc. One or more storage devices (e.g., non-volatile memory) may include ROM, flash memory, hard drive, or any other suitable optical, magnetic, or solid-state storage medium or combinations thereof. One or more storage devices may store data, instructions (e.g., software or firmware for controlling motor 16, flame effect system 12, etc.), and any other suitable data.

[0019] As illustrated, battery 24 is electrically connected to controller 26 and configured to supply power to controller 26. Therefore, battery 24 is electrically connected to motor 16 via controller 26. Additionally, controller 26 is configured to control the rotational speed of each motor 16, thereby controlling the height, attitude, and direction of movement of UAV 10. In some embodiments, the UAV may include one or more actuators configured to control the orientation of one or more motors. In such embodiments, the controller may be communicatively coupled to the actuator(s), and the controller may control the speed of the actuator(s) and the motors to control the height, attitude, and direction of movement of the UAV.

[0020] In the illustrated embodiment, UAV 10 includes an altimeter 32 communicatively coupled to controller 26. In some embodiments, altimeter 32 is coupled to body 14 (e.g., disposed within a cavity of the body, coupled to an external surface of the body, etc.). Altimeter 32 is configured to output an altitude signal indicating the altitude of UAV 10. Controller 26 is configured to determine the altitude of UAV 10 based on feedback from altimeter 32.

[0021] In the illustrated embodiment, UAV 10 includes a spatial positioning system 34 communicatively coupled to controller 26. In some embodiments, spatial positioning system 34 is coupled to body 14 (e.g., disposed within a cavity of the body, coupled to an external surface of the body, etc.). Spatial positioning system 34 is configured to output a position signal indicating the position, orientation, linear velocity, angular velocity, or a combination thereof of UAV 10. Controller 26 is configured to determine the position, orientation, linear velocity, angular velocity, or a combination thereof of UAV 10 based on feedback from spatial positioning system 34. Spatial positioning system 34 may include one or more suitable spatial positioning devices, such as a Global Positioning System (GPS) receiver.

[0022] While the UAV includes an altimeter 32 and a spatial positioning system 34 in the illustrated embodiment, the altimeter and / or spatial positioning system may be omitted in other embodiments. Furthermore, in some embodiments, the UAV may include one or more other sensors configured to provide position and / or orientation feedback to the controller. For example, in some embodiments, the UAV may include a gyroscope sensor (e.g., a solid-state gyroscope, etc.), an inertial navigation sensor, a RADAR sensor, a LiDAR sensor, one or more other suitable sensors, or combinations thereof. Additionally, in some embodiments, the UAV may include an impact sensor, a camera, an infrared sensor, one or more other suitable sensors, or combinations thereof. Each sensor may be communicatively coupled to the controller and configured to output one or more corresponding sensor signals to the controller.

[0023] In the illustrated embodiment, UAV 10 includes a transceiver 36 communicatively coupled to controller 26. In some embodiments, transceiver 36 is coupled to body 14 (e.g., disposed within a cavity of the body, coupled to an external surface of the body, etc.). Transceiver 36 is configured to receive input from and / or to a remote operator and / or a remote base station. For example, in some embodiments, transceiver 36 may receive one or more input signals for controlling the movement of UAV 10 (e.g., discrete movement control, flight path, etc.) and / or for controlling flame effect system 12 (e.g., discrete enable and / or disable commands, including planning for enabling and / or disabling the flame effect system (one or more) at positions and / or (one or more) at times, etc.). Alternatively or concurrently, transceiver 36 may output one or more signals indicating the position and / or orientation of UAV 10, the operational status of UAV 10, the status of flame effect system 12 (e.g., enabled, disabled), the operational status of the flame effect system, one or more other suitable parameters or combinations thereof. While the UAV includes transceiver 36 in the illustrated embodiment, the transceiver may be omitted in other embodiments. In such embodiments, the controller may operate the UAV based on stored flight paths and flame effect system plans.

[0024] As discussed in detail below, the flame effect system 12 includes a hopper configured to store powdered fuel (e.g., lycopodium powder, etc.) and a propellant tank configured to store propellant (e.g., carbon dioxide). Additionally, the flame effect system 12 includes a nozzle configured to discharge the powdered fuel into the atmosphere and a fluid path extending from the propellant tank to the nozzle. The hopper is fluidly connected to the fluid path at a junction between the propellant tank and the nozzle, and the hopper is configured such that the powdered fuel can flow into the fluid path under the influence of gravity. In some embodiments, the flame effect system 12 includes a valve disposed along the fluid path between the propellant tank and the junction. The valve is configured to selectively open to allow propellant to flow through the fluid path to fluidize the powdered fuel and drive the powdered fuel through the nozzle. In some embodiments, the flame effect system 12 includes an igniter positioned at or near the nozzle. The igniter is configured to activate to initiate a combustion reaction between the powdered fuel and atmospheric oxygen, thereby generating a flame effect.

[0025] Additionally, as discussed in detail below, controller 26 is communicatively connected to the valves and igniter of flame effect system 12. Controller 26 is configured to command the valves to open and the igniter to activate (e.g., for a selected duration) to initiate a combustion reaction. Additionally, controller 26 is configured to command the valves to close to terminate the combustion reaction. Therefore, controller 26 can selectively enable and disable flame effect system 12 during operation of UAV 10. In some embodiments, controller 26 can enable flame effect system 12 in response to receiving a control signal via transceiver 36. For example, an automatic control system at the operator or base station can cause the base station to output a signal to UAV 10 indicating a command to enable flame effect system 12, and controller 26 can enable flame effect system 12 in response to receiving such a signal via transceiver 36. Furthermore, in some embodiments, a plan for operating flame effect system 12 can be stored within controller 26. For example, the plan can be received from the base station via transceiver, and / or from a device (e.g., a computer, tablet, mobile storage device, etc.) connected to the controller via a wired and / or wireless connection. The plan may include instructions for enabling and / or disabling the flame effects system 12 based on the location of the UAV, the orientation of the UAV, a specific time, or a combination thereof.

[0026] In some embodiments, controller 26 is configured to deactivate or prevent the activation of flame effect system 12 in response to determining that the altitude of UAV 10 is below a threshold altitude (e.g., 10 meters, 5 meters, 3 meters, etc.). For example, in response to determining that the altitude of UAV 10 is below a threshold altitude, controller 26 may instruct a valve to close or prevent a valve from opening, and deactivate or prevent the igniter from activating. In some embodiments, controller may deactivate or prevent the activation of flame effect system in response to determining that the difference between the UAV's position and its expected position (e.g., based on its flight path, etc.) is greater than a threshold distance and / or determining that the difference between the UAV's attitude and its expected attitude (e.g., based on its flight path, etc.) is greater than a threshold angle. Additionally, in some embodiments, controller may deactivate or prevent the activation of flame effect system in response to determining that the distance between the UAV (e.g., the nozzle of the UAV's flame effect system) and a detected object (e.g., detected by a RADAR sensor, LiDAR sensor, etc.) is less than a threshold distance.

[0027] Furthermore, in some embodiments, controller 26 is configured to deactivate or prevent the activation of flame effect system 12 in response to detecting a landing force greater than a threshold landing force. For example, in response to detecting a landing force greater than the threshold landing force, controller 26 may instruct a valve to close or prevent a valve from opening, and deactivate or prevent the igniter from activating. By way of example, if the UAV lands with a force greater than the threshold landing force (e.g., as monitored by an impact sensor), one component of flame effect system 12 may shift relative to another component of flame effect system 12 (e.g., the propellant tank may become disconnected from the fluid path, etc.). Therefore, in response to detecting a landing force greater than the threshold landing force, controller may deactivate or prevent the activation of flame effect system until a reset command is received from the operator after a check of the flame effect system.

[0028] Figure 3 It is possible Figure 1 A schematic diagram of an embodiment of a flame effect system 12 used within a UAV. In the illustrated embodiment, the flame effect system 12 includes a hopper 38 configured to store powdered fuel 40. The hopper 38 may be formed of one or more suitable materials, such as one or more polymeric materials, one or more metallic materials, one or more composite materials, etc. Furthermore, the hopper 38 may have any suitable shape and size (e.g., based on the configuration of the UAV body, based on the expected operating duration of the flame effect system 12, etc.). Additionally, the hopper 38 may include a hatch configured to selectively open to allow filling of the hopper 38 with powdered fuel 40 and to close to contain the powdered fuel 40 within the hopper 38. The powdered fuel 40 may include one or more suitable types of powder configured to burn in the presence of atmospheric oxygen (e.g., where atmospheric oxygen is the only oxidant). For example, the powdered fuel can only be ignited in the presence of a single oxidant (e.g., atmospheric oxygen). In some embodiments, the powdered fuel 40 is only phycocyanin powder. However, other powdered fuels may be used. For example, powdered fuels may include (e.g., contain) (one or more) powdered metals (e.g., magnesium, aluminum, etc.), wheat flour, corn starch, coal powder, (one or more) other suitable types of powders or combinations thereof.

[0029] Furthermore, in the illustrated embodiment, the flame effect system 12 includes a propellant canister 42 configured to store propellant. The propellant canister 42 may be formed of one or more suitable materials, such as one or more polymeric materials, one or more metallic materials, one or more composite materials, etc. Furthermore, the propellant canister 42 may have any suitable shape and size (e.g., based on the configuration of the UAV body, based on the expected operating duration of the flame effect system 12, etc.). In some embodiments, the propellant canister 42 may be a single-use, commercially available propellant cartridge. In some embodiments, the propellant canister may include a connector (e.g., a Schrader valve, etc.) configured to facilitate filling and / or refilling the propellant canister with propellant. The propellant may include any suitable type of pressurized propellant (e.g., stored as a liquid and / or gas). For example, in some embodiments, the propellant is non-flammable and non-oxidizing, such as carbon dioxide or nitrogen. However, in other embodiments, the propellant may be oxidizing, such as air, oxygen, or nitrous oxide.

[0030] Additionally, in the illustrated embodiment, the flame effect system 12 includes a nozzle 44 configured to discharge powdered fuel 40 into the atmosphere, and the flame effect system 12 includes a fluid path 46 extending from the propellant tank 42 to the nozzle 44. The fluid path 46 may be formed of one or more suitable materials, such as one or more polymeric materials, one or more metallic materials, one or more composite materials, etc. Furthermore, the fluid path 46 may have any suitable cross-sectional area and cross-sectional shape (e.g., circular, etc.). In the illustrated embodiment, the cross-sectional area and cross-sectional shape of the fluid path 46 are constant along its length. However, in other embodiments, the cross-sectional area and / or cross-sectional shape of the fluid path may vary along its length (e.g., the fluid path may have one or more convergent-divergent sections, etc.).

[0031] In the illustrated embodiment, the flame effect system 12 includes a connector 48 configured to selectively engage a propellant canister 42 to a fluid path 46. For example, in some embodiments, the connector 48 may include an internal thread configured to engage a corresponding external thread of the propellant canister 42. In such embodiments, the propellant canister 42 can be engaged to the fluid path 46 by rotating the propellant canister 42 to screw the external thread of the propellant canister 42 into the internal thread of the connector 48. In some embodiments, the connector 48 may include one or more other suitable connecting means (e.g., alone or in conjunction with the thread), such as one or more latches, one or more clamps, one or more other suitable connecting means, or combinations thereof. The connector 48 facilitates the removal and replacement of the propellant canister 42 (e.g., when the propellant in the propellant canister 42 is depleted). In some embodiments, the connector 48 is configured to open the propellant canister 42 when it is engaged with the connector 48. For example, in some embodiments, a seal may be positioned at the outlet of the propellant tank, and the connector may include a pin configured to pierce the seal when the propellant tank engages with the connector, thereby opening the propellant tank. In some embodiments, the propellant tank may include a valve (e.g., a Schrader valve, etc.) positioned at the outlet of the propellant tank, and the connector may include a protrusion configured to engage the valve in response to engagement of the propellant tank and the connector, thereby opening the propellant tank. Although in the illustrated embodiment, the flame effect system 12 includes a connector 48, in other embodiments, the connector may be omitted (e.g., the propellant tank may be fixedly coupled to a fluid path).

[0032] Nozzle 44 may be formed of one or more suitable materials, such as one or more ceramic materials, one or more metallic materials, one or more composite materials, etc. Because nozzle 44 is exposed to heat from the flame effect, nozzle 44 may be formed of one or more materials configured to resist heat from the flame effect. In the illustrated embodiment, nozzle 44 is coupled to fluid path 46. However, in other embodiments, the nozzle may be integrally formed with the fluid path (e.g., the nozzle may be formed at the outlet of the fluid path). Nozzle 44 may have any suitable shape (e.g., circular cross-sectional shape, etc.) and size. In the illustrated embodiment, nozzle 44 expands in the direction of flow of propellant and powdered fuel 40 through the nozzle. However, in other embodiments, the nozzle may converge in the direction of flow, the nozzle may converge and expand in the direction of flow, or the nozzle may have a constant inner cross-sectional area.

[0033] As illustrated, hopper 38 is fluidly connected to fluid path 46 at a junction 50, which is positioned between propellant tank 42 and nozzle 44. In the illustrated embodiment, flame effect system 12 includes a second fluid path 52 that fluidly connects hopper 38 to fluid path 46. However, in other embodiments, hopper may be directly connected to fluid path 46. In embodiments, hopper 38 is configured such that powdered fuel 40 can flow into fluid path 46 under the influence of gravity (e.g., via second fluid path 52). Therefore, in such embodiments, flame effect system 12 does not include any means configured to drive powdered fuel 40 into fluid path 46 (e.g., a motor-driven rotating wheel, etc.). Thus, the cost, weight, and complexity of flame effect system 12 can be reduced (e.g., compared to flame effect systems having means configured to drive powdered fuel into fluid paths). Furthermore, certain powdered fuels (e.g., lycopodium powder, etc.) may tend to agglomerate at the junction 50 (e.g., due to the weight of the powdered fuel in the hopper 38 acting on the powdered fuel in the fluid path 46 at the junction 50), thereby preventing the powdered fuel from flowing through the fluid path 46 until the powdered fuel 40 is fluidized by the flowing propellant. Therefore, when the propellant does not flow through the fluid path 46, the powdered fuel 40 may remain (or substantially remain) within the fluid path 46. The propellant tank 42 is configured to discharge propellant through the fluid path 46 to fluidize the powdered fuel 40 at the junction 50 and drive the powdered fuel 40 through the nozzle 44. Thus, a combustion reaction can be initiated between the powdered fuel 40 and atmospheric oxygen, thereby generating a flame effect. Although in the illustrated embodiment, the flame effect system 12 does not include any means configured to drive powdered fuel 40 into the fluid path 46, in other embodiments, the flame effect system may include means configured to drive powdered fuel into the fluid path (e.g., a motor-driven rotating wheel, etc.).

[0034] In the illustrated embodiment, the flame effect system 12 includes a valve 54 disposed along a fluid path 46 between the propellant tank 42 and the manifold 50. The valve 54 is configured to selectively open to allow propellant flow through the fluid path 46. Additionally, the valve 54 is configured to selectively close to prevent propellant flow through the fluid path 46. In the illustrated embodiment, the valve 54 is communicatively coupled to a controller 26, and the controller 26 is configured to command the valve to open and close. Although the illustrated embodiment includes a valve 54, in other embodiments, the valve may be omitted, and the flame effect system may include a device configured to selectively open and close the propellant tank to selectively facilitate and prevent propellant flow through the fluid path.

[0035] In the illustrated embodiment, the flame effect system 12 includes an igniter 56 positioned at a nozzle 44. The igniter 56 is configured to activate to initiate a combustion reaction between powdered fuel 40 and oxygen in the atmosphere, thereby generating a flame effect. The igniter 56 may include any suitable ignition device (e.g., a spark igniter, plasma igniter, etc.) configured to initiate a combustion reaction between the powdered fuel 40 and oxygen in the atmosphere. While the igniter 56 is positioned at the nozzle 44 in the illustrated embodiment, in other embodiments, the igniter may be positioned near the nozzle (e.g., coupled to the body of the UAV) to ignite the powdered fuel exiting from the nozzle. Furthermore, while the flame effect system 12 includes an igniter 56 in the illustrated embodiment, the igniter may be omitted in other embodiments. For example, in some embodiments, the powdered fuel 40 may include one or more components configured to automatically ignite in response to diffusion in the atmosphere.

[0036] By way of example, to induce a flame effect, controller 26 may first instruct valve 54 to open, thereby facilitating propellant flow through fluid path 46. As the propellant flows through fluid path 46, it fluidizes the powdered fuel 40 accumulated at junction 50, and drives the fluidized powdered fuel through fluid path 46 and nozzle 44. Controller 26 then instructs igniter 56 to activate, thereby initiating a combustion reaction between the powdered fuel 40 diffused through nozzle 44 and atmospheric oxygen. Thus, flame effect system 12 generates a flame effect. In some embodiments, controller 26 may instruct igniter 56 to activate for a selected duration after instructing valve 54 to open. The selected duration may correspond to sufficient time for the fluidized powdered fuel 40 to flow from junction to the outlet of nozzle 44. In some embodiments, controller 26 may instruct igniter 56 to activate for a sufficient duration to initiate a combustion reaction between powdered fuel 40 and atmospheric oxygen. Additionally, in some embodiments, controller 26 may instruct valve 54 to open for a selected duration based on the desired duration of the flame effect. Each duration can be stored in the controller 26 and / or input by the operator (e.g., via input to the base station).

[0037] In the illustrated embodiment, the flame effect system 12 includes an orifice plate 58 disposed along a second fluid path 52. The orifice plate 58 is configured to control the flow rate of powdered fuel 40 from the hopper 38 into the fluid path 46. In some embodiments, the orifice plate 58 has a fixed orifice area, and the orifice area can be selected based on the desired size of the flame effect. For example, a smaller orifice area can reduce the flow rate of powdered fuel into the fluid path, thereby reducing the size of the flame effect, and a larger orifice area can increase the flow rate of powdered fuel into the fluid path, thereby increasing the size of the flame effect. As discussed in detail below, in some embodiments, the orifice area of ​​the orifice plate can be adjustable to control the size of the flame effect. In some embodiments, the orifice plate can be omitted. In such embodiments, the flow rate of powdered fuel into the fluid path can be established based on the outlet area of ​​the hopper and / or the cross-sectional area of ​​the second fluid path.

[0038] In some embodiments, valve 54 is adjustable to control the flow rate of propellant through fluid path 46. For example, the valve may include an iris valve, a ball valve, or another suitable type of valve. Controller 26 may control valve 54 to control the flow rate of propellant through fluid path 46. For example, controller 26 may control valve 54 to increase the propellant flow rate when the valve is open, thereby establishing a longer flame effect, and controller 26 may control valve 54 to decrease the propellant flow rate when the valve is open, thereby establishing a shorter flame effect. While adjustable valves have been disclosed above, in some embodiments, the valve may simply switch between a closed position and a fixed (e.g., non-adjustable) open position.

[0039] In some embodiments, the orifice plate 58 is adjustable to control the flow of powdered fuel 40 from the hopper 38 into the fluid path 46. For example, the orifice plate 58 may include an iris valve or another suitable type of valve, and the valve may control the orifice area of ​​the orifice plate 58. In the illustrated embodiment, the orifice plate 58 includes an actuator 60 configured to control the valve, and a controller 26 is communicatively coupled to the actuator 60 of the orifice plate 58. The controller 26 may control the actuator 60 to control the orifice area, thereby controlling the flow rate of the powdered fuel 40 into the fluid path 46. For example, the controller 26 may control the orifice plate 58 to increase the orifice area, thereby increasing the flow rate of the powdered fuel 40 into the fluid path 46. Therefore, the size of the flame effect can be increased. Alternatively, the controller 26 may control the orifice plate 58 to decrease the orifice area, thereby decreasing the flow rate of the powdered fuel 40 into the fluid path 46. Therefore, the size of the flame effect can be decreased. While adjustable orifice plates have been disclosed above, in some embodiments, the orifice area of ​​the orifice plate may be fixed. In such embodiments, the actuator may be omitted. In some embodiments, the orifice plates may be interchangeable, thereby allowing the operator to select an orifice plate with the desired orifice area and to position the orifice plate along the second fluid path 52.

[0040] In some embodiments, nozzle 44 is adjustable to control the diffusion of powdered fuel 40 into the atmosphere. For example, the outlet shape and / or outlet area of ​​nozzle 44 may be adjustable. In the illustrated embodiment, nozzle 44 includes an actuator 62 (e.g., a nozzle actuator) configured to adjust the outlet shape and / or outlet area, and controller 26 is communicatively coupled to actuator 62 of nozzle 44. Controller 26 can control actuator 62 to control the outlet shape and / or outlet area of ​​nozzle 44, thereby controlling the diffusion of powdered fuel 40 into the atmosphere. While adjustable nozzles have been disclosed above, in some embodiments, the outlet shape and outlet area of ​​the nozzle may be fixed. In such embodiments, the actuator may be omitted. In some embodiments, nozzles may be interchangeable, thereby enabling an operator to select a nozzle with a desired outlet shape and / or outlet area and to connect the nozzle to a fluid path.

[0041] While only certain features have been illustrated and described herein, many modifications and alterations will occur to those skilled in the art. Therefore, it is to be understood that the appended claims are intended to cover all such modifications and alterations that fall within the true spirit of this disclosure.

[0042] The techniques presented and claimed herein are referred to and applied to material objects and specific examples that can arguably improve the practical nature of the art, and are therefore not abstract, intangible, or purely theoretical. Furthermore, if any claim appended to this specification contains one or more elements designated as “device for [performing]…[function]” or “step for [performing]…[function]”, such elements are intended to be interpreted according to 35 USC 112(f). However, for any claim containing elements designated in any other manner, such elements are intended not to be interpreted according to 35 USC 112(f).

Claims

1. A flame effect system for an unmanned aerial vehicle (UAV), the flame effect system comprising: The hopper is configured to store powdered fuel; Propellant tank, which is configured to store propellant; A nozzle configured to discharge the powdered fuel into the atmosphere; as well as A fluid path extending from the propellant tank to the nozzle, wherein the hopper is fluidly connected to the fluid path at the junction between the propellant tank and the nozzle, the hopper being configured to allow the powdered fuel to flow into the fluid path, and the propellant tank being configured to discharge the propellant through the fluid path to fluidize the powdered fuel within the fluid path and to drive the fluidized powdered fuel through the nozzle.

2. The flame effect system according to claim 1, comprising an igniter, the igniter being positioned at or near the nozzle, wherein, The igniter is configured to activate to initiate a combustion reaction between the fluidized powdered fuel and oxygen in the atmosphere.

3. The flame effect system according to claim 1, comprising a valve disposed along the fluid path between the propellant tank and the junction, wherein, The valve is configured to open selectively to allow the propellant to flow through the fluid path.

4. The flame effect system according to claim 3, wherein, The valve is adjustable to control the flow rate of the propellant through the fluid path.

5. The flame effect system according to claim 1, wherein, The powdered fuel includes lycopodium powder, and the propellant includes carbon dioxide, or a combination thereof.

6. The flame effect system according to claim 1, wherein, The hopper is configured such that the powdered fuel can flow into the fluid path under the influence of gravity.

7. The flame effect system according to claim 1, comprising: A second fluid path fluidly connects the hopper to the fluid path; as well as An orifice plate disposed along the second fluid path, wherein the orifice plate is configured to control the flow rate of the powdered fuel into the fluid path.

8. The flame effect system according to claim 1, wherein, The nozzle's outlet shape, outlet area, or combination thereof is adjustable.

9. An unmanned aerial vehicle (UAV), comprising: main body; At least one motor is connected to the main body; At least one propeller connected to the at least one motor; A battery, which is connected to the main body and electrically connected to the at least one motor; as well as A flame effect system, connected to the main body, wherein the flame effect system includes: The hopper is configured to store powdered fuel; Propellant tank, which is configured to store propellant; A nozzle configured to discharge the powdered fuel into the atmosphere; and A fluid path extending from the propellant tank to the nozzle, wherein the hopper is fluidly connected to the fluid path at the junction between the propellant tank and the nozzle, the hopper being configured to allow the powdered fuel to flow into the fluid path, and the propellant tank being configured to discharge the propellant through the fluid path to fluidize the powdered fuel within the fluid path and to drive the fluidized powdered fuel through the nozzle.

10. The UAV according to claim 9, wherein, The flame effect system includes an igniter located at or near the nozzle and configured to activate to initiate a combustion reaction between the fluidized powdered fuel and oxygen in the atmosphere.

11. The UAV according to claim 9, wherein, The flame effect system includes a valve disposed along the fluid path between the propellant tank and the junction, and the valve is configured to selectively open to allow the propellant to flow through the fluid path.

12. The UAV according to claim 9, wherein, The powdered fuel includes lycopodium powder, and the propellant includes carbon dioxide, or a combination thereof.

13. The UAV according to claim 9, wherein, The hopper is configured such that the powdered fuel can flow into the fluid path under the influence of gravity.

14. The UAV according to claim 9, wherein, The flame effect system includes: A second fluid path fluidly connects the hopper to the fluid path; and An orifice plate disposed along the second fluid path, wherein the orifice plate is configured to control the flow rate of the powdered fuel into the fluid path.

15. A flame effect system for an unmanned aerial vehicle (UAV), the flame effect system comprising: The hopper is configured to store powdered fuel; Propellant tank, which is configured to store propellant; A nozzle configured to discharge the powdered fuel into the atmosphere; A fluid path extending from the propellant tank to the nozzle, wherein the hopper is fluidly connected to the fluid path at the junction between the propellant tank and the nozzle, and the hopper is configured such that the powdered fuel can flow into the fluid path; A valve is disposed along the fluid path between the propellant tank and the junction, wherein the valve is configured to selectively open to allow the propellant to flow through the fluid path to fluidize the powdered fuel within the fluid path and to drive the fluidized powdered fuel through the nozzle; An igniter, positioned at or near the nozzle, wherein the igniter is configured to activate to initiate a combustion reaction between the fluidized powdered fuel and oxygen in the atmosphere; and A controller communicatively connected to the valve and the igniter, wherein the controller includes a memory and a processor, and the controller is configured to instruct the valve to open and the igniter to activate to initiate the combustion reaction.

16. The flame effect system of claim 15, further comprising a nozzle actuator configured to adjust the outlet shape, outlet area, or a combination thereof of the nozzle, wherein, The nozzle actuator is communicatively connected to the controller, and the controller is configured to control the nozzle actuator.

17. The flame effect system according to claim 15, wherein, The hopper is configured such that the powdered fuel can flow into the fluid path under the influence of gravity.

18. The flame effect system according to claim 15, comprising: A second fluid path fluidly connects the hopper to the fluid path; as well as An orifice plate disposed along the second fluid path, wherein the orifice plate is configured to control the flow rate of the powdered fuel into the fluid path; The orifice plate is communicatively connected to the controller, and the controller is configured to control the orifice area of ​​the orifice plate to control the flow rate of the powdered fuel into the fluid path.

19. The flame effect system according to claim 15, wherein, The controller is configured to instruct the valve to close and the igniter to deactivate in response to determining that the UAV is below a threshold height.

20. The flame effect system according to claim 15, wherein, The controller is configured to instruct the valve to close and the igniter to deactivate in response to detecting that the landing force is greater than a threshold landing force.

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