Propulsor fan and method of operating such

Abstract

This invention discloses a propeller fan and drive system with reduced noise emissions. The propeller fan includes a blade fan having a plurality of blades. The blade fan is tensioned at the tips of the plurality of blades. By tensioning the tips of the blades, an angle of the blades is maintained during operation of the propeller fan, thereby reducing noise that can be caused by changes in the angle of the blades.

Description

[Technical Field]

[0001] The present invention generally relates to a propulsion fan and a drive system. [Previous Technology]

[0002] Conventional propeller fans typically consist of an open rotor and a propeller. These types of conventional propeller fans have reached their acoustic limits. Conventional propellers contain two to five blades supported on a single side, thereby limiting the blade count to five or fewer. To make a conventional propeller emit sound at a frequency imperceptible to the human ear, the fan speed must be increased. However, due to the single-sided support structure, conventional propellers cannot be driven at higher speeds. Furthermore, because conventional propeller fans are supported on only one side, the angle of the fan blades can change as the blades rotate at a faster speed, resulting in variations in the pitch audible to the human ear. This increases noise pollution. [Summary of the Invention]

[0003] A propeller fan and drive system for reducing noise pollution are disclosed. The propeller fan includes a blade fan having a plurality of blades. The blade fan is tensioned at the tips of the plurality of blades. In one embodiment, a tension ring connected to the tips of the blades tensions the tips of the blades. Furthermore, the propeller fan includes a locking ring configured to connect to the roots of the plurality of blades to tension the roots of the blades. By tensioning the tips and roots of the plurality of blades, the blades maintain the same shape and torsion during thrust generation and at rest, thereby reducing noise that can be caused by changes in the angle of the blades.

Implementation Method

[0026] Cross-reference to related applications

[0027] This application claims priority to U.S. Provisional Patent Application No. 63 / 155,968, filed March 3, 2021; U.S. Provisional Patent Application No. 63 / 156,063, filed March 3, 2021; U.S. Provisional Patent Application No. 63 / 156,067, filed March 3, 2021; and U.S. Provisional Patent Application No. 63 / 156,076, filed March 3, 2021, the entire contents of which are incorporated herein by reference.

[0028] The figures and the following description are for illustrative purposes only and illustrate certain embodiments. Those skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein can be employed without departing from the principles described herein. Reference will now be made in detail to several embodiments, examples of which are illustrated in the accompanying drawings. It should be noted that similar or identical element symbols may be suitably used in the figures and may indicate similar or identical functions. Propeller fan and drive system

[0029] In one embodiment, a propulsion fan and drive system are disclosed. Generally, the propulsion fan and drive system are configured to generate thrust. The propulsion fan and drive system can generate thrust for a variety of applications, from aircraft to hand tools such as a leaf blower. However, the applications of the propulsion fan and drive system are not limited to those described herein.

[0030] Figure 1 illustrates a perspective view of a thruster fan 100 according to one embodiment. Generally, the thruster fan 100 includes a plurality of components that collectively reduce noise emitted by the thruster fan 100 during thrust generation. Therefore, the thruster fan 100 reduces noise pollution. For example, the thruster fan 100 includes a tensioned-blade fan comprising a plurality of fan blades. By tensioning the blades, the angles of the fan blades are maintained substantially the same, whether the thruster fan is generating maximum thrust or not operating (e.g., stationary). Therefore, noise pollution is reduced and thrust efficiency is improved compared to conventional thrusters. Given that the angles of the fan blades are maintained within a predetermined tolerance range, the thruster fan 100 reduces noise pollution. For example, the thruster fan 100 emits less than 65 dBA at 300 feet edge / 5,000 lbf.

[0031] According to one embodiment, FIG2A illustrates a first exploded view of one type of propeller fan 100 and FIG2B illustrates a second exploded view of one type of propeller fan 100. The propeller fan 100 includes a plurality of different components shown in FIG2A and FIG2B. In one embodiment, the propeller fan 100 includes a duct leading edge 201, a nose cone 203, a hub 205, a blade fan 209, a locking ring 210 (shown in FIG8A to FIG8C), a tension ring 211, a motor 215, a housing 217, a plurality of outer casings 213A and 213B, a stator 219, and a tail cone 221. Other embodiments of the propeller fan 100 may include components other than those shown in FIG2A and FIG2B. In one embodiment, a portion of the duct leading edge 201, the outer casing 213, and the stator 219 (e.g., 219C) together form a circulation duct housing the propeller fan components, as shown in FIG1.

[0032] Figures 3A, 3B, 3C, and 3D respectively illustrate a perspective view, a front view, a side view, and a cross-sectional view of a duct leading edge 201 of a propeller fan 100 according to one embodiment. In one embodiment, the duct leading edge 201 is configured to provide a clean air inflow to the propeller fan 100. In one embodiment, the duct leading edge 201 is configured to connect to a housing 217. The duct leading edge 201 may include a plurality of mounting holes 223 on a rear surface of the duct leading edge 201, as shown in Figure 2B. Fasteners (e.g., nuts and bolts, rivets, etc.) are inserted into the mounting holes 223 to connect the duct leading edge 201 to a first end 1001 of the housing 217, as will be further described below.

[0033] The leading edge 201 of the duct may include a plurality of panels that together form the leading edge 201 of the duct. For example, the leading edge 201 of the duct may include a first plurality of panels that together form an inner surface 309 of the leading edge 201 of the duct and a second plurality of panels that together form an outer surface 307 of the leading edge 201 of the duct, such that the leading edge 201 of the duct has the ability to guide air through it to a hollow center of a bladed fan 209. The first and second plurality of panels may be connected to each other by various fastening members such as fasteners (e.g., screws, nuts, bolts) or by welding. The first and second plurality of panels may be made of metals such as aluminum or titanium or composite materials such as carbon fiber. Alternatively, the leading edge 201 of the duct may be made of a single piece of material and may be (e.g.) 3D printed.

[0034] In one embodiment, the leading edge 201 of the duct includes a first end 303 (e.g., an inlet) and a second end 305 (e.g., an outlet). The first end 303 receives air and the air exits from the second end 305. As shown in FIG3C, one diameter of the first end 303 is smaller than one diameter of the second end 305, but may be the same in other embodiments. The diameters of the first end 303 and the second end 305 of the leading edge 201 of the duct depend on the application of the propeller fan 100. For example, the diameters of the first end 303 and the second end 305 of the leading edge 201 of an aircraft application are larger than those of a blade blower application.

[0035] Figure 3D is a cross-sectional view of a duct leading edge 201 along plane A-A' shown in Figure 3B according to one embodiment. As previously mentioned, the duct leading edge 201 includes an outer surface 307 and an inner surface 309. Both the outer surface 307 and the outer surface 309 extend from a first end 303 of the duct leading edge 201 toward a second end 305 of the duct leading edge 201. Airflow passes through the inner surface 309 of the duct leading edge 201. A curvature 311A ​​of the inner surface 309 and a curvature 311B of the outer surface 307 of the duct leading edge 201 are designed to balance various factors and Reynolds numbers such as different conditions (e.g., flight conditions such as cruise, takeoff, and landing). Those skilled in the art will be able to adjust the duct leading edge radius for favorable pressure gradients across the speed states and flight modes of interest.

[0036] Figures 4A, 4B, 4C, and 4D respectively illustrate a perspective view, a front view, a cross-sectional view, and a perspective view of a cross-section of a nose cone 203 of a propeller fan 100 according to one embodiment. The nose cone 203 is configured to regulate the behavior of the oncoming airflow and reduce aerodynamic drag. The nose cone 203 may also be configured with an impeller to draw in a mass flow of cooling air without significantly causing broadband or tonal noise.

[0037] In one embodiment, the nose cone 203 is configured to connect to the motor 215, and the hub 205 is disposed between the nose cone 203 and the motor 215. The nose cone 203 may include a plurality of mounting holes on the rear surface of one of the nose cones 203, as shown in FIG2B. Fasteners 207 (e.g., nuts and bolts, rivets, etc.) are inserted into the mounting holes to connect the nose cone 203 to a first end of one of the hubs 205. As will be further described below, the fasteners 207 extend through the hub 205 and connect to a first end of one of the motors 215.

[0038] In one embodiment, the nose cone 203 is conical in shape. However, in other embodiments, the nose cone 203 may have a different shape. As shown in Figures 4A to 4D, the nose cone 203 includes an opening 403 (e.g., a hole) at one of its first ends. As the blade fan 209 rotates, air is drawn through the opening 403 in the nose cone 203 to cool the motor 215. The secondary mass flow required to cool the internal components determines the inner diameter of the opening 403 of the nose cone 203. Those skilled in the art will be able to deduce this diameter based on the thermal requirements of different electric motors and the amount of air required to cool the electric motor under the most restrictive conditions (typically maximum continuous operation).

[0039] FIG4C is a cross-sectional view of a nose cone 203 along plane B-B' shown in FIG4B according to one embodiment. In one embodiment, the nose cone 203 is not solid, but includes a cavity. For example, in one embodiment, the nose cone 203 includes an air passage 405. The air passage 405 extends from an opening 403 in the nose cone 203 to a plurality of openings 407 arranged circumferentially around a second end (e.g., the rear surface) of the nose cone 203. Air flows from the opening 403 through the air passage 405 and exits the plurality of openings 407 to cool the motor 215. In one embodiment, the air passage 405 is formed between an outer surface 409 of the nose cone 203 and a protrusion 411 formed within the nose cone 203, as shown in FIG4C and FIG4D.

[0040] In one embodiment, the protrusion 411 protrudes inward from the second end of the nasal cone 203 toward the opening 403 of the nasal cone 203. The protrusion 411 may have a shape similar to that of the nasal cone 203. For example, the protrusion 411 may also be conical. However, in other embodiments, the protrusion 411 may have a shape different from that of the nasal cone 203.

[0041] Generally, the protrusion 411 has a size and shape tuned to allow mass airflow to cool the motor 215. In one embodiment, the protrusion 411 includes an air passage 413 formed through the protrusion 411, through which air flows from an opening 415 to an opening 417 on the second end of the nose cone 203. In one embodiment, the center of the air passage 413 is aligned with the center of an opening 403 in the nose cone 203.

[0042] Figures 5A and 5B respectively illustrate a front view and a side view of a hub 205 of a propeller fan 100 according to one embodiment. The hub 205 is the central portion of the propeller fan 100 and is located at the center of a blade fan 209, as will be further described below. In one embodiment, the hub 205 is configured to connect to the nose cone 203, the locking ring 210, and the motor 215.

[0043] As shown in Figures 5A and 5B, in one example, the hub 205 is cylindrical in shape. In one embodiment, the diameter of a first end 507 of the hub 205 matches the diameter of a second end of the nose cone 203. The first end 507 of the hub 205 (e.g., a front surface) includes a plurality of mounting holes 501A to 501F formed through the thickness of the hub 205. The mounting holes 501 are positioned such that when the second end of the nose cone 203 engages with the first end 507 of the nose hub 205, the mounting holes 501 align with the mounting holes of the nose cone 203. Fasteners 207 are configured to pass through the mounting holes 501A to 501F and are connected to a first end (e.g., a front surface) of the motor 215. For example, the fastener 207 is screwed into a threaded hole 225 on the first end of the motor 215.

[0044] In one embodiment, the hub 205 also includes a plurality of openings 503, such as openings 503A and 503B, extending through the thickness of the hub 205. The plurality of openings 503 have a shape and size that matches (e.g., is the same as) one of the openings 407 in the rear surface of the nose cone 203. The openings 503 are configured to align with the openings 407 in the rear surface of the nose cone 203 when the nose cone 203 and the hub 205 are engaged with each other. Thus, airflow exiting the openings 407 of the nose cone 203 flows through the openings 503 included in the hub 205. In one embodiment, the plurality of openings 503 included in the hub have different sizes. For example, opening 503A is smaller than opening 503B.

[0045] In one embodiment, the hub 205 also includes an opening 505 extending through a portion of the thickness of the hub 205. The opening 505 is located at a center of the hub 205. In one embodiment, the center of the opening 505 is configured to align with a center of an air passage 413 of the nose cone 203. Thus, airflow exiting the air passage 413 of the nose cone 203 flows through the opening 505 in the hub 205 to cool the motor 215.

[0046] In one embodiment, a second end 511 of one of the hubs 205 opposite to the first end 507 includes a connecting mechanism 509 surrounding the outer circumference of the second end 511 of the hub 205. The connecting mechanism 509 is configured to connect the hub 205 to a locking ring 210. In one embodiment, the connecting mechanism 509 is threaded such that the hub 205 is screwed into the locking ring 210. Once the hub 205 is connected to the locking ring 210, the locking ring 210 surrounds the outer circumference of the hub 205. The motor 215 is configured to engage with the outer end face of the second end 511 of the hub 205.

[0047] In one embodiment, the hub 205 includes an intermediate region 511 disposed between a first end 507 and a second end 511 of the hub 205. In one embodiment, the blade fan 209 is configured to be disposed around the circumference of the intermediate region 511 when the hub 205 is placed through the center of one of the blade fans 209.

[0048] Figures 6A and 6B respectively illustrate a perspective view and a front view of a bladed fan 209 of a propeller fan 100 according to one embodiment. As shown in Figures 6A and 6B, the bladed fan 209 includes a plurality of blades 601. The total number of blades 601 included in the bladed fan 209 is significantly greater than the number of blades included in a conventional propeller fan having 2 to 5 blades. In one embodiment, the bladed fan 209 may include a range of blades 601 from 20 to 840 blades. However, any number of blades greater than 5 may be used. Generally, the total number of blades 601 included in the bladed fan 209 depends on the application. In one embodiment, the material of the blades used for the multi-bladed fan also depends on the type of application of the multi-bladed fan. The blades may be made of metals such as aluminum or titanium or composite materials such as carbon fiber.

[0049] In one embodiment, when the blade fan 209 rotates at a low tip speed (approximately 300 ft / sec to approximately 450 ft / sec), the blade fan 209 reduces overall blade noise. As described herein, tensioning the fan blades 209 allows for more blades within mechanical material constraints while still achieving ultrasonic characteristics and low subsonic tip speeds. Furthermore, the higher number of blades 601 raises the tonal noise to ultrasonic frequencies exceeding the upper limit of human hearing (≥16,000 Hz for a typical adult). Additionally, the lower blade load due to the higher blade count also reduces the severity of vortex and vortex collisions that cause broadband noise.

[0050] As shown in Figures 6A and 6B, a plurality of blades 601 are configured to form an annular shape having a hollow center in which a hub 205 is housed. Each blade 601 is positioned such that at least a portion of its leading and trailing edges overlap with adjacent blades 601. For example, a leading edge of a given blade overlaps with the trailing edge of a blade to the left of a given blade, and a trailing edge of a given blade overlaps with the leading edge of a blade to the right of a given blade. The overlapping configuration of the plurality of blades 601 provides increased solidity to perform work on the inlet airflow. This solidity is tuned to take into account local aerodynamic effects and can be tuned to take into account the Reynolds number that can affect laminar adhesion within and between blades.

[0051] Figures 7A, 7B, 7C, and 7D respectively illustrate a perspective view, a front view, a side view, and a top view of one of the blades 601 included in the bladed fan 209 shown in Figures 6A and 6B according to one embodiment. In one embodiment, each blade 601 includes a first locking end 605, a second locking end 603, and a flap 607 disposed between the first locking end 605 and the second locking end 603. In other embodiments, the blade 601 may include features other than those described herein.

[0052] In one embodiment, a first locking end 605 is located at the tip of blade 601. The first locking end 605 is configured to insert into tension ring 211 and lock blade 601 into tension ring 211, thereby tensioning the tip of blade 601. By tensioning the tip of blade 601, the pitch (e.g., angle) of the tip of blade 601 is substantially the same during thrust generation or when the propeller fan 100 is stationary, thereby reducing noise pollution.

[0053] As shown in Figures 7A to 7D, the first locking end 605 is rectangular in shape with chamfered edges, but other shapes may be used for the first locking end 605. In one embodiment, the first locking end 605 has a width and thickness greater than the tip of the blade 607. However, in other embodiments, the first locking end 605 may have a width equal to or narrower than the tip of the blade 601. Those skilled in the art will adjust the edges, chamfers, surface treatments, and baffle treatments to take into account the localized stresses and strains attributable to tension.

[0054] In one embodiment, the second locking end 603 is located at the root of the blade 601. The second locking end 603 is configured to insert into the locking ring 210 and lock the blade 601 into the locking ring 210. By tensioning the root of the blade 601, the pitch (e.g., angle) of the root of the blade 601 is substantially the same during thrust generation or when the propeller fan 100 is stationary, thereby reducing noise pollution. As shown in Figures 7A to 7D, the second locking end 603 has a plurality of different surfaces (e.g., straight surfaces and curved surfaces) to increase the surface area of ​​contact with the locking ring 210 to reduce blade deflection. In one embodiment, the second locking end 603 has a width greater than the root of the blade 601 and wider than one of the widths of the first locking end 605. However, in other embodiments, the second locking end 603 may have a width equal to or narrower than the root of the blade 601.

[0055] The winglet 607 is disposed between the first locking end 605 and the second locking end 603. In one embodiment, the winglet 607 includes one of the geometric twists 609. The geometric twist 609 is a variation of the winglet tilt angle measured relative to the root of the blade 601. That is, due to the geometric twist 609, the winglet 607 includes a plurality of different tilt angles across the length of the winglet 607. For example, the winglet 607 may have a first tilt angle at a first side of the geometric twist 609 (e.g., below the geometric twist 609 in Figures 7A to 7C) and a second tilt angle at a second side of the geometric twist 609 (e.g., above the geometric twist 609 in Figures 7A to 7C).

[0056] Due to the geometric twist 609, when viewed from the top view of the blade 601 as shown in FIG. 7D, the first locking end 605 and the second locking end 603 are misaligned with each other. In one embodiment, the geometric twist 609 begins at a portion of the wing 607 closer to the root of the blade 601 than at the tip of the blade 601. The geometric twist 609 between the root and tip chords can vary by up to 45 degrees.

[0057] Referring back to Figures 6A and 6B, in one embodiment, the blades 601 are positioned such that the second locking ends 603 are arranged parallel to each other around a circumference, thereby forming a hole at the center of the blade fan 209. Therefore, the first locking ends 605 are also arranged parallel to each other, and the blades 607 of each blade 601 overlap with another blade of an adjacent blade 601 due to the geometric twist 609 in the blades 607.

[0058] Figures 8A, 8B, and 8C respectively illustrate a perspective view, a front view, and a side view of a locking ring 210 of a propeller fan 100 according to one embodiment. Generally, the locking ring 210 is configured to connect to the blade fan 209 and the hub 205 and advantageously tension the root of the blades 601. Thus, the blades 601 of the blade fan 209 are tensioned at both the tip and the root to maintain the angle of the blades 601 during operation. The locking ring 210 may be made of a metal such as aluminum or titanium or a composite material such as carbon fiber.

[0059] The locking ring 210 includes a first end 801 and a second end 803. In one embodiment, the first end 801 has a diameter smaller than that of the second end 803, thereby forming a conical shape. This shape is adapted to the needs of the primary internal flow (i.e., non-cooling flow) to the fan and can also take into account any boundary layer pressure gradient along the central body when the fan is present. In one embodiment, the first end 801 of the locking ring 210 is configured to directly connect the bladed fan 209 to the locking ring 210, thereby locking the bladed fan 209 to the locking ring 210. The first end 801 of the locking ring 210 includes a plurality of locking teeth 805. In one embodiment, the locking teeth 805 are protrusions extending from a body of the locking ring 210 at an angle relative to a reference perpendicular to the second end 803 of the locking ring.

[0060] A plurality of slots 807 are formed between the locking teeth 805. For example, a slot 807 is formed between one pair of locking teeth including locking teeth 805A and locking teeth 805B. The slot 807 has a width and depth that match the dimensions of the second locking end 603 of the blade fan 209. The slot 807 extends partially through the thickness of the locking ring 210, such as (for example) ¾ of the thickness of the locking ring 210.

[0061] In one embodiment, each of the plurality of slots 807 is configured to connect to a corresponding one of the plurality of blades 601 of the blade fan 209. Specifically, the second locking end 603 of each blade 601 is inserted into one of the slots 807, thereby securing the blade 601 to the locking ring 210 through direct contact between the second locking end 603 and the surface of the locking teeth 805 forming the slot. In one embodiment, a fastener such as epoxy resin is also applied to the second locking end 603 of each blade 601 to further strengthen the connection between the blade 601 and the locking ring 210. By locking the second locking end 603 of the blade 601 to the locking ring 210, the pitch of the root of the blade 601 remains substantially the same during thrust generation or when stationary, thereby reducing audible noise from the propeller fan 100, since pitch changes are perceptible to the human ear.

[0062] In one embodiment, the second end 803 of the locking ring 210 includes a connecting mechanism 809 at one inner circumference of the second end 803 of the locking ring 210. The connecting mechanism 809 is configured, for example, to connect the locking ring 210 to a connecting mechanism 509 of the hub 205. In one embodiment, the connecting mechanism 809 is threaded to match the thread of the connecting mechanism 509 of the hub 205, thereby allowing the hub 205 to be screwed into the locking ring 210. Since the motor 215 is connected to the hub 205, the hub 205 rotates, thereby causing the locking ring 210 and the blade fan 209 to rotate as well.

[0063] Figures 9A and 9B respectively illustrate a perspective view and a side view of a tension ring 211 of a propeller fan 100 according to one embodiment. The tension ring 211 is configured to be connected to the blade fan 209 by being placed around the circumference of the blade fan 209. More specifically, according to one embodiment, the tension ring 211 is configured to be connected to all the first locking ends 605 of the blade fan 209. By locking the first locking ends 605 of the blade 601 to the tension ring 211, the pitch of the tip of the blade 601 remains substantially the same during thrust generation and at rest, thereby reducing audible noise from the propeller fan 100, since pitch changes are perceptible to the human ear. Therefore, using the tension ring 211 to pretension the blade 601 reduces inefficiencies attributable to tip gaps. In one embodiment, the tension ring 211 is made of a metal such as aluminum or titanium or a composite material such as carbon fiber. However, in other embodiments, other materials may be used.

[0064] As shown in Figures 9A and 9B, the tension ring 211 includes a first end 903 and a second end 905. In one embodiment, the first end 903 has a diameter substantially the same as that of the second end 905. The body 909 of the tension ring 211 is disposed between the first end 903 and the second end 905.

[0065] In one embodiment, the body 909 of the tension ring 211 includes a plurality of openings (e.g., slots) 907 extending through the entire thickness of the tension ring 211. Each opening 907 is configured to connect to a first locking end 605 of one of the plurality of blades 601. Thus, there is a one-to-one relationship between each opening 907 of the tension ring 211 and each blade 601. In one embodiment, a fastener, such as epoxy resin, is also applied to the first locking end 605 of each blade 601 to further strengthen the connection between the blade 601 and the tension ring 211.

[0066] In one embodiment, a plurality of openings 907 are formed at an angle relative to a reference perpendicular to either the first end 903 or the second end 905. The angle at which the openings 907 are formed matches the pitch of the first locking end 605 of the blade 601. The size of the openings 907 substantially matches the size of the first locking end 605, such that once the first locking end 605 is inserted into the opening 907 of the tension ring 211 and the first locking end 605 is in direct contact with the tension ring 211, the first locking end 605 is locked to the tension ring 211.

[0067] Figures 10A, 10B, and 10C illustrate a perspective view, a front view, and a side view of an inner duct housing 217 (hereinafter referred to as a "housing") of a propeller fan 100 according to one embodiment. In one embodiment, the housing 217 is configured to house (e.g., partially surround) components of the propeller fan 100. For example, in one embodiment, a blade fan 209, a hub 205, a tension ring 211, a locking ring 210, and a motor 215 are housed within the housing 217. In other embodiments, other components of the propeller fan 100 may be housed within the housing 217. In one embodiment, the housing 217 is made of a metal such as aluminum or titanium or a composite material such as carbon fiber. However, other materials may be used in different embodiments.

[0068] In one embodiment, the housing 217 is cylindrical and includes a first end 1001 (e.g., an inlet) and a second end 1003 (e.g., an outlet). In one embodiment, the first end 1001 has a diameter larger than that of the second end 1003. The first end 1001 includes a plurality of mounting holes 1005 formed around the circumference of the first end 1001 of the housing 217. In one embodiment, the first end 1001 of the housing 217 is configured to connect to the second end 305 of the duct leading edge 201, such that the mounting hole 223 of the duct leading edge 201 is aligned with the mounting hole 1005 of the housing 217. As previously mentioned above, fasteners 207 can be used to secure the duct leading edge 201 to the first end 1001 of the duct housing 217.

[0069] In one embodiment, the second end 1003 of the housing 217 includes a plurality of mounting holes 1007 formed around the circumference of the second end 1003 of the housing 217. In one embodiment, the second end 1003 of the housing 217 is configured to connect to a first end (e.g., an inlet) of the stator 219. When the second end 1003 of the housing 217 is connected to the first end of the stator 219, the mounting holes 1007 in the second end 1003 of the housing 217 are aligned with mounting holes on the first end of the stator 219. Fasteners (e.g., nuts, bolts, rivets) can be used to secure the second end 1003 of the housing 217 to the first end of the stator 219.

[0070] In one embodiment, the housing 217 includes a plurality of intermediate portions 1009 configured to accommodate different components of a propeller fan. The plurality of intermediate portions 1009 includes a first intermediate portion 1009A extending from a first end 1001 and a second intermediate portion 1009B extending from a second end 1003. The intermediate portions 1009 of the housing 217 are disposed between the first end 1001 and the second end 1003 of the housing 217.

[0071] As shown in FIG10C, the first intermediate portion 1009A has a diameter different from that of the second intermediate portion 1009B. For example, the diameter of the first intermediate portion 1009A is larger than the diameter of the second intermediate portion 1009B. Furthermore, the first intermediate portion 1009A has a diameter smaller than that of the first end 1001 and the second intermediate portion 1009B has a diameter smaller than that of the second end 1003.

[0072] In one embodiment, the first intermediate portion 1009A is configured to accommodate the hub 205, the blade fan 209, the locking ring 210, and the tension ring 211. Since the tension ring 211 has the largest diameter of the components housed in the first intermediate portion 1009A, the diameter 1009A of the first intermediate portion 1009A is based on the diameter of the tension ring 211. In one embodiment, the diameter of the first intermediate portion 1009A is substantially the same as the diameter of the tension ring 211, thereby attributing, for example, a press-fit that allows the tension ring 211 to be securely fastened within the first intermediate portion 1009A.

[0073] In one embodiment, the second intermediate portion 1009B is configured to accommodate a portion of the motor 215 and the stator 219. The length of the second intermediate portion 1009B is based on a length of the motor 215 and a length of a portion of the stator 219 housed within the intermediate portion. The second intermediate portion 1009B has a length at least as long as the portions of the motor 215 and the stator 219 to accommodate the portions of the motor 215 and the stator 219 within the second intermediate portion 1009B. In one embodiment, the diameter of the second intermediate portion 1009B is based on the mass airflow entering and exiting the stator 219. Those skilled in the art will be able to adjust the diameter to induce favorable pressure gradients across multiple design speeds of interest to minimize flow separation or vortices. The interior of the second portion 1009B can also be tuned to reduce noise.

[0074] Figures 11A, 11B, 11C, and 11D respectively illustrate a perspective view, a front view, a side view, and a cross-sectional view of a stator 219 of a propeller fan 100 according to one embodiment. In one embodiment, the stator 219 includes a plurality of stator blades 219A, a motor housing 219B, and a stator housing 219C. In other embodiments, the stator 219 may include components other than those shown in Figures 11A to 11D.

[0075] In one embodiment, the motor housing 219B is cylindrical and includes a first end 1101 and a second end 1103, as shown in FIG11D. FIG11D illustrates a cross-sectional view of a stator 219 along plane C-C' of FIG11B according to one embodiment. As shown in FIG11D, the motor housing 219B includes a cavity 1105 disposed between the first end 1101 and the second end 1103. The cavity 1105 may extend from the first end 1101 toward the second end 1103, but does not extend to the second end 1103. In one embodiment, the cavity 1105 is configured to receive a motor 215. That is, the motor 215 is placed within the cavity 1105 of the motor housing 219B. Therefore, the shape and size of the cavity 1105 depend on the shape and size of the motor 215. Since the motor 215 is placed inside the cavity 1105 and is indirectly connected to the hub 205, the stator 219 also serves as a structural component to support the hub 205 and other components of the propeller 100.

[0076] In one embodiment, the motor housing 219B includes a hole 1113 passing through the center of the motor housing 219B, as shown in Figures 11B and 11D. The diameter of the hole 1113 is smaller than the diameter of the motor 215 to prevent the motor 215 from falling through the hole 1113. The hole 1113 is placed in the motor housing 219B to assist in heat dissipation, thereby cooling the motor 215.

[0077] Referring to FIG11B, the stator 219 includes a plurality of stator blades 219A. The stator blades 219A extend radially from the motor housing 219B. That is, the root of each blade 219A is connected to the motor housing 219B and the blades of the stator blades 219A extend outward away from the motor housing 219B. In one embodiment, each blade 219A extends away from the motor housing 219B at an angle measured relative to a reference line, the reference line extending perpendicularly from a point on the motor housing 219B from which the stator blade 219A extends.

[0078] In one embodiment, stator blades 219A carry away heat from motor 215. Since blades 219A contact the motor housing 219B that houses motor 215, the airflow through blades 219A dissipates heat generated by motor 215. In one embodiment, the configuration of blades 219A also reduces noise generated by blade fan 209 and controls thrust generated by propeller fan 100. The blade count of stator blades 219A can be selected such that stator harmonics cancel out harmonics of blade fan 209. For ultrasonic fans, due to the locally low Reynolds number along the blades, those skilled in the art will see that blade fan 209 can carry a plurality of blades 601 with a higher count (e.g., total number) than stator blades 219A to improve acoustic performance. This can vary from 50% to 200% of the blade count for a particular set of design tones.

[0079] In one embodiment, the stator housing 219C is configured to accommodate the stator blades 219A and the motor housing 219B. That is, the stator blades 219A are placed within the stator housing 219C such that the stator housing 219C surrounds the circumference of the blades 219A. In one embodiment, the stator housing 219C includes a first end 1107 (e.g., an inlet) and a second end 1109 (e.g., an outlet). As shown in FIG11C, the first end 1107 has a diameter larger than that of the second end 1109. Therefore, the stator housing 219C may have a tapered shape. However, in other embodiments, the stator housing 219C may have other shapes.

[0080] Referring to FIG11D, in one embodiment, the tip of blade 219A contacts an inner surface 1111 of stator housing 219C. Therefore, the stator blades 219A are fixed. By contacting the blades 219A with the inner surface 1111 of stator housing 219C, the position of each blade 219A remains unchanged.

[0081] Figures 12A, 12B, 12C, and 12D respectively illustrate a perspective view, a front view, a side view, and a cross-sectional view of a tail cone 221 of a propeller fan 100 according to one embodiment. In one embodiment, the tail cone 221 is configured to produce the correct area change of the stator housing 219C by allowing air to exit the propeller fan 100. The tail cone 221 may be made of a metal such as aluminum or titanium or a composite material such as carbon fiber.

[0082] The tail cone 221 includes a first end 1201 (e.g., an inlet) and a second end 1203 (e.g., an outlet). In one embodiment, the first end 1201 has a diameter larger than the diameter of the second end 1203. In one embodiment, the diameter of the tail cone 221 varies across its length. As shown in FIG12C, the diameter of the tail cone 221 decreases from the first end 1201 toward the second end 1203 until it reaches an intermediate point 1205. From the intermediate point 1205 to the second end 1203, the diameter of the tail cone 221 is relatively constant.

[0083] In one embodiment, a first end 1201 of the tail cone 221 is configured to connect to a second end 1103 of the motor housing 219B of the stator 219. Therefore, the diameter of the first end 1201 of the tail cone 221 substantially matches one of the diameters of the second end 1103 of the motor housing 219B of the stator 219. In one embodiment, the first end 1201 of the tail cone 221 includes a mounting surface 1209 that mates with (e.g., contacts) the second end 1103 of the motor housing 219B. The mounting surface 1209 can be attached to the motor housing 219B using, for example, fasteners. However, in other embodiments, other attachment mechanisms may be used.

[0084] Referring to FIG12D, a cross-sectional view of the tail cone 221 along plane D-D' shown in FIG12B is shown. In one embodiment, the tail cone 221 includes a cavity 1207 formed along the length of the tail cone 221 extending from a first end 1201 to a second end 1203. The shaping of the rear end of the tail cone 221 is controlled by the expansion of the secondary flow discharged from the interior of the tail cone 221 relative to the jet following the bladed disk and / or stator.

[0085] In one embodiment, the propeller fan 100 includes a central hub drive motor 215. That is, in one embodiment, a single motor 215 drives the propeller fan 100. An exemplary motor for the propeller fan 100 is an electric motor. However, in other embodiments, other types of motors, such as a gas engine or a jet turbine, may be used in the propeller fan 100. Generally, different motor types and sizes may be used depending on the application of the propeller fan 100. Multi-motor drive system

[0086] In another embodiment, the propeller fan 100 may be driven by a plurality of motors instead of the single motor 215 described above. Figures 13A, 13B and 13C respectively illustrate a perspective view, a front view and a side view of a circumferential multi-motor drive system for a propeller fan 100 according to one embodiment.

[0087] Instead of using a single motor 215 to drive the thrust, a plurality of auxiliary motors 1301A, 1301B, 1301C, and 1301D are placed within housing 217 to drive the blade fan 209 via a ring gear 1303. In one embodiment, the plurality of auxiliary motors 1301 may be electric motors. However, other types of motors may be used.

[0088] In one embodiment, the ring gear 1303 may be connected to the tension ring 211. The auxiliary motor 1301 may replace or be used in conjunction with the motor 215 described above. Multi-motor redundancy allows for fault tolerance of the thruster fan 100 system. For example, with four auxiliary motors 1301, the loss of a single auxiliary motor is virtually negligible for the normal operation of the thruster. Even if another motor is lost, the remaining auxiliary motors 1301 can still generate sufficient thrust at overspeed.

[0089] As shown in Figures 13A to 13C, auxiliary motors 1301A to 1301D are radially distributed around the circumference of the thruster 100, rather than all located at the hub 205 of the thruster. Each auxiliary motor 1301 has an end portion including a gear connected to one of the ring gears 1303. The radial arrangement is not limited to equal angular spacing. For example, a fan could be driven by three motors offset towards the lower quarter of the duct. Furthermore, since the stator 219 does not support the hub 205 to support the centrally housed motor 215, the thruster can utilize the duct structure itself to handle the motors and their loads. In addition to removing weight and drag, this also results in less bandwidth noise typically caused by stator-current interactions. In one embodiment, the auxiliary motors 1301 operate at up to 20,000 RPM, whereby the auxiliary motors can produce an excellent 15 kW / kg specific power compared to a heavier, lower-speed motor with a specific power of 5 kW / kg. The auxiliary motor 1301 drives the ring gear 1303 consistently to eliminate gear slippage (in both the axial and radial directions). This low load results in lower gear noise.

[0090] Figure 14 illustrates yet another embodiment of a circumferential drive system for a thruster fan 100 according to another embodiment. The embodiment shown in Figure 14 is similar to the example described in Figure 13. However, the drive system shown in Figure 14 omits the central drive motor 215 and relies on an auxiliary motor 1301 to generate thrust. Thruster array

[0091] Figures 15A and 15B illustrate a front view and a perspective view, respectively, of a thruster fan array 1500 according to one embodiment. In one embodiment, the thruster fan array 1500 includes a plurality of thruster fans 100 arranged laterally to form a row of thruster fans. In the example shown in Figures 15A and 15B, the thruster fan array 1500 includes a first thruster fan 100A, a second thruster fan 100B, and a third thruster fan 100C. Each of the plurality of thruster fans 100A to 100C includes the thruster fan structure described herein. Although three thruster fans 100 are included in the thruster fan array 1500, the array may include any number of thruster fans greater than two.

[0092] Figure 16 illustrates an exemplary application of a propeller fan array 1600 according to one embodiment. As shown in Figure 16, the propeller fan array 1600 includes a plurality of propeller fans as described herein. In one embodiment, the propeller fan array 1600 is integrated into a ducted wing 1603 of an aircraft 1605. The plurality of propeller fans can be laterally combined to form a ducted wing 1603. The ducted wing 1603 can be shaped to produce a passive lift biplane in which biplane staggering, sweeping, taper, and dihedral angles can be added as needed. The total number of propeller fans included in the array 1600 and the size of the propeller fans depend on the requirements of the aircraft, such as (e.g.) the number of passengers on board, speed requirements, and altitude requirements of the aircraft 1605.

[0093] Combining the thruster fans into an array provides several control and thrust steering opportunities. Thrust can be varied only between individual thruster fans 100 to induce yaw, roll, or pitch moments. The relative spanwise pitch difference between the thruster fans can be used to facilitate faster climbs and descents. This can be further enhanced with additional control surfaces mounted at the trailing edge.

[0094] The spanwise arrangement of the ducts is well-suited for integration along the wing or even into the biplane wing itself. The array can be configured and expanded to create a biplane wing with swept, staggered, dihedral, and tapered configurations to meet system requirements. The choice to integrate the propeller fan array into a complete biplane wing depends on the required thrust (minus drag) and the relative size of the propeller fans. Propeller fan applications.

[0095] Figures 17A, 17B, and 17C respectively illustrate a front view, a side view, and a top view of a hovering drone 1700 according to one embodiment. The hovering drone 1700 includes a thruster fan array comprising a first thruster fan 100A, a second thruster fan 100B, and a third thruster fan 100C. Although only three thruster fans are included in the hovering drone 1700, the hovering drone 1700 may include additional or fewer thruster fans than shown in Figures 17A to 17C.

[0096] The Hovering Drone 1700 series comprises a low-noise, electric vertical takeoff and landing (VTOL) drone with one of the propeller fan arrays described herein. The Hovering Drone 1700 can be used for short-range operations, such as in urban environments. The Hovering Drone 1700 may have a 360-degree camera and sensors and may be capable of hovering flight times of, for example, greater than 15 minutes. In one example, propeller fans 100A to 100C may each have an augmented turntable load of 1 ft diameter and 6.4 lb / ft². The Hovering Drone 1700 may have a maximum takeoff weight of 30 lbs.

[0097] In the example shown in Figure 17A, each thruster fan 100A to 100C includes a hub-driven center positioning motor 215 and the auxiliary motor 1301 described above. However, the hovering drone 1700 may omit the auxiliary motor 1301 and include only the center positioning motor 215, or it may omit the center positioning motor 215 and include only the auxiliary motor 1301.

[0098] Figures 18A, 18B, and 18C respectively illustrate a front view, a side view, and a top view of a cinema drone 1800 including a thruster fan array according to one embodiment. Generally, the cinema drone 1800 is a low-noise deflection slipstream VTOL drone used for cinematic needs. The cinema drone 1800 can be all-electric or hybrid-powered. The cinema drone 1800 can have, for example, a gimbal-mounted payload (e.g., a main camera) of up to 35 pounds. The cinema drone 1800 can include auxiliary cameras and sensors. The cinema drone 1800 can be used for hovering flight time of more than 20 minutes. In one embodiment, the cinema drone can have a maximum cruising speed of more than 50 mph.

[0099] In one embodiment, the cinema drone 1800 is a biplane with a neutral staggered arrangement. As shown in FIG18A, the cinema drone 1800 includes a first wing 1801 and a second wing 1803. Each of the first wing 1801 and the second wing 1803 includes a thruster fan array comprising a plurality of thruster fans. For example, the thruster fan array included in wing 1801 includes thruster fans 100A, 100B, 100C, and 100D, while the thruster fan array included in wing 1803 includes thruster fans 100E, 100F, 100G, and 100H. Thus, half of the thruster fans are located on a first side of fuselage 1805 and the remaining half are located on a second side of fuselage 1805. In the example shown in FIGS. 18A to 18C, the thruster array comprises eight thrusters, but any number of thrusters may be used.

[0100] The wings 1801 and 1803 of the cinematic drone 1800 shown in Figures 18A to 18C have angular sweeps formed between the two wings near the forward portion of the fuselage 1805. In the example shown in Figures 18A to 18C, wings 1801 and 1803 may have a wing dihedral angle of 20 degrees and a wing sweep of 30 degrees. However, other angles may be used in different embodiments.

[0101] In one embodiment, in one instance, the cinema drone 1800 shown in Figures 18A to 18C has a maximum takeoff weight of 75 lbs and a target maximum payload weight of 30 lbs. For example, each thruster fan 100 may have a fan diameter of 1 ft and an augmentation turntable load of 6.0 lb / ft². The fuselage 1805 of the cinema drone 1800 may have a length of 5.5 ft and a width of 0.6 ft. For example, the wingspan of the cinema drone 1800 may be 8.8 ft, with a wing area of ​​17.4 ft² and a wing load of 4.3 lb / ft².

[0102] Figures 19A, 19B, and 19C respectively illustrate a front view, a side view, and a top view of a transport aircraft 1900 including a propeller fan array according to one embodiment. The transport aircraft 1900 is a manned VTOL aircraft. The transport aircraft 1900 may be hybrid-powered or fully electric. For example, the transport aircraft 1900 may have a range of 20 to 60 nautical miles at an operating altitude of 1,000 to 2,000 feet and a cruising speed of 130 to 250 knots.

[0103] In one embodiment, the transport aircraft 1900 is a biplane with a slightly negative crossover. The transport aircraft 1900 includes a first wing 1901 and a second wing 1903. An angle is formed between the two wings 1901 and 1903 at the front of the fuselage 1905. In the examples shown in Figures 19A to 19C, the wings may have a dihedral angle of 5 degrees and a wing sweep of -25 degrees. However, other angles may be used in different embodiments.

[0104] In one embodiment, a propeller fan array is integrated into each of the wings 1901 and 1903. A first propeller fan array is located on a first side of one of the fuselages 1905 and integrated into the wing 1901, and a second propeller fan array is located on a second side of one of the fuselages 1905 and integrated into the wing 1903. For example, the propeller fan array included in the wing 1901 includes propeller fans 100A, 100B, 100C, and 100D, while the propeller fan array included in the wing 1903 includes propeller fans 100E, 100F, 100G, and 100H. Thus, half of the propeller fans are located on the first side of one of the fuselages 1905 and the remaining half are located on the second side of one of the fuselages 1905. In the example shown in Figures 19A to 19C, the propeller array includes eight propeller fans, but any number of propeller fans can be used.

[0105] In one embodiment, in one instance, the transport aircraft 1900 has a maximum takeoff weight of 1,000 pounds and a target maximum payload weight of 220 pounds. Each propeller fan 100 may have a fan diameter of 3 ft and an augmented turntable load of 6.0 lb / ft². The fuselage 1905 of the transport aircraft 1900 may have a length of 9.2 ft and a width of 3.75 ft. The wingspan of the transport aircraft 1900 may be 28.7 ft, having a wing area of ​​106.3 ft² and a wing loading of 9.4 lb / ft².

[0106] Figures 20A, 20B, and 20C respectively illustrate a front view, a side view, and a top view of a vertical takeoff and landing (VTOL) aircraft 2000 including a propeller fan array according to one embodiment. The VTOL aircraft 2000 is a manned VTOL aircraft as appropriate. The VTOL aircraft 2000 can be hybrid-powered or fully electric. The VTOL aircraft 2000 can have a range of 20 to 400 nautical miles at an operating altitude of 1,000 to 2,000 feet and a cruising speed of 130 to 250 knots. In one embodiment, the VTOL aircraft 2000 is capable of hovering.

[0107] In the examples shown in Figures 20A to 20C, the VTOL aircraft 2000 is a biplane with a slightly negative crossover. The VTOL aircraft 2000 includes a first wing 2001 and a second wing 2003. In one embodiment, an angle is formed near the forward portion of the fuselage 2005 between the two wings 2001 and 2003. The wings 2001 and 2003 may have a dihedral angle of 5 degrees and a wing sweep angle of -25 degrees. However, other angles may be used in different embodiments.

[0108] In one embodiment, a propeller fan array is integrated into each of the wings 2001 and 2003. A first propeller fan array is located on a first side of one of the fuselages 2005 and integrated into the wing 2001, and a second propeller fan array is located on a second side of one of the fuselages 2005 and integrated into the wing 2003. For example, the propeller fan array included in the wing 2001 includes propeller fans 100A, 100B, 100C, and 100D, while the propeller fan array included in the wing 2003 includes propeller fans 100E, 100F, 100G, and 100H. Thus, half of the propeller fans are located on a first side of one of the fuselages 2005 and the remaining half are located on a second side of one of the fuselages 2005. In the example shown in Figures 20A to 20C, the propeller array includes eight propeller fans, but any number of propeller fans can be used.

[0109] In one example, the VTOL aircraft 2000 has a maximum takeoff weight of 5,000 lbs and a target maximum payload weight of 1,000 lbs (e.g., for 3 to 4 passengers). Each propeller fan 100 may have a fan diameter of 5 ft and an augmented turntable load of 11.0 lb / ft². For example, the fuselage 2005 of the VTOL aircraft 2000 may have a length of 24.7 ft and a width of 5 ft. For example, the wingspan of the VTOL aircraft 2000 may be 49 ft, with a wing area of ​​300 ft² and a wing loading of 16.7 lb / ft².

[0110] Figures 21A, 21B, and 21C respectively illustrate a front view, a side view, and a top view of a delivery drone 2100 including a thruster fan array according to one embodiment. The delivery drone 2100 may have a 360-degree camera and sensors and can be used for hovering flight time of more than 20 minutes. In one embodiment, the delivery drone 2100 may have a maximum cruising speed of more than 50 mph.

[0111] The delivery drone 2100 is an example configured to deliver an internally packaged electric tail-sitting VTOL drone. In the illustrated example, the delivery drone 2100 is a biplane with a neutral crossover. In one embodiment, the delivery drone 2100 includes a first wing 2101 and a second wing 2103, with an angle sweep formed between the two wings near the rear of the fuselage 2105.

[0112] In one embodiment, a propeller fan array is integrated into each of the wings 2101 and 2103. A first propeller fan array is located on a first side of one of the fuselage 2105 and integrated into the wing 2101, and a second propeller fan array is located on a second side of one of the fuselage 2105 and integrated into the wing 2103. For example, the propeller fan array included in the wing 2101 includes propeller fans 100A, 100B, and 100C, while the propeller fan array included in the wing 2103 includes propeller fans 100D, 100E, and 100F. Thus, half of the propeller fans are located on a first side of one of the fuselage 2105 and the remaining half are located on a second side of one of the fuselage 2105. In the example shown in Figures 21A to 21C, the propeller array includes six propeller fans, but any number of propeller fans can be used.

[0113] In one example, the delivery drone 2100 has a maximum takeoff weight of 55 lbs and a maximum target payload weight of 5.5 lbs. Each propeller fan 100 may have a fan diameter of 1 ft and an augmented turntable load of 6.0 lb / ft². The fuselage 2105 of the delivery drone 2100 may have a length of 6.7 ft and a width of 1.3 ft. For example, the wingspan of the delivery drone 2100 may be 8.8 ft, with a wing area of ​​21.9 ft² and a wing load of 2.5 lb / ft². Free blades

[0114] Since the propeller fan 100 described herein has a high speed capability exceeding 150 mph, it is desirable to provide improved propulsion efficiency through blade angle variability or mass flow throttling. As described above, the propeller fan 100 contains a significantly higher blade count than conventional propellers. From a mechanical complexity perspective, implementing a typical variable pitch propeller mechanism would be too cumbersome.

[0115] In one embodiment, one of the propeller fan arrays described above uses a free-wing blade structure incorporated into an aircraft. The free-wing blade structure can be implemented in, for example, any aircraft described in Figures 17 to 21 above. The free-wing blade is a propeller fan capable of free rotation along its radial axis due to mass balance in front of the aerodynamic center of each blade. That is, the blade fan 209 is capable of free rotation along its radial axis due to mass balance in front of the aerodynamic center of each blade. The free-wing blade combines winglet design, wing mass balance, and a wing pivot to achieve the ability of one wing to freely pivot under all flight conditions when automatically balanced to a zero pitch moment according to a constant CL.

[0116] The combination of the free blade structure and the propeller fan 100 creates a passive system for variable blade angle of attack (AoA) while maintaining a constant blade load. This provides a unique synergy to the electric motor-driven propeller fan 100, as the electric motor can operate efficiently across a wide rpm range. The electric motor can operate at higher or lower radial velocities across different inflow velocities, and the blades "float" to align their AoA to maintain the same load-average lift coefficient (CL). This capability also provides the value of achieving lower noise as a way to avoid blade stall, which causes high noise under different flight conditions and at vortex levels.

[0117] The use of free blades results in numerous benefits. For example, by adding mass to the leading-edge blades, the pitch-balanced free blades are always at an AoA close to their L / Dmax CL (typically 0.5 to 1.0). This ensures that the blade AoA is always matched to the inflow and that there is never any flow separation. Furthermore, when the inner hub area is empty, the propeller fan 100 can be mass-balanced because it is rim-driven to provide volume in front of the blades for the lightest mass balance counterweight (without exposure to the flow). This allows the propeller fan 100 to vary its rpm by approximately 50% during different flight phases so that the blades can always remain close to their optimal advance ratio. The combination of free blades and electric motors provides specific benefits because, unlike turbines or internal combustion engines, electric motors have a wide range of high-efficiency rpms. Therefore, turbines or internal combustion engines need to operate at a fixed rpm at a given power, while electric motors do not. This allows the propeller to vary its rpm by approximately 50% during different flight phases so that the blades can always remain close to their optimal advance ratio. Finally, due to the wider AoA variation and thrust requirements, free blades can also facilitate larger-scale VTOL integration. (Circulating duct control)

[0118] In one embodiment, a circulation control mechanism is positioned at the leading edge 201 of the duct. The circulation control mechanism is configured to blow an air jet at the leading edge 201 of the duct. By applying air to the leading edge 201 of the duct, the leading edge 201 can achieve an increase in leading edge suction. In one embodiment, a combination of an electric motor and a centrifugal or axial compressor is embedded in the remaining duct volume to increase the circulation control blowing and / or suction at the leading edge 201 of the duct. By applying distributed electric propulsion (DEP) for internal circulation control blowing at the leading edge 201 of the duct, static and low-speed thrust can be increased with lower power compared to providing additional power to the thruster. This internal application of DEP maximizes aerospace integration benefits for both the thruster fan 100 and the aircraft integration stage. For example, applying circulation control at the leading edge 201 of the duct results in an increase in static thrust of up to 40% at the same fan power.

[0119] In one embodiment, an emergency-powered ramjet turbine with a high PR and intake velocity requires a high circulation control jet blowing velocity (i.e., close to sonic noise jet). A low-noise, low-speed jet (approximately 300 ft / sec) can be used and can be powered by a small internal duct electric centrifugal blower.

[0120] Given the much lower PR and static duct inflow velocity, a lower-velocity circulating control jet can be equally effective in increasing thrust of the propeller. The effectiveness of the circulating control varies depending on Vjet / Vintake. Another interesting aspect of circulating control duct leading-edge blowing is avoiding leading-edge separation within the duct at high angles of attack (i.e., during the transition period). This is an important consideration for duct-type eVTOLs; if the inlet airflow separates at the leading edge of the duct, noise increases significantly because the fan blades experience oscillating flow conditions that cause the circulating blades to be under load.

[0121] By applying cyclic controlled blowing at the duct leading edge 201 at a jet velocity of approximately 300 ft / sec, the suction at the duct leading edge can be increased to account for approximately 75% of the total static thrust. Blowing at the duct leading edge 201 effectively provides aerodynamic shape deformation on the duct leading edge to entrain additional ambient air. With blowing in, the inflowing air "sees" a much larger flared duct leading edge, which is desirable under static conditions. A duct inlet with an actual flared opening would cause significant drag during cruise. When blowing is relatively ineffective, the duct cyclic controlled blowing can be shut off during cruise flight. A compact high-speed centrifugal blower operates via ultrasonic blades to provide internal blowing. Although cyclic controlled blowing is most effective at high nozzle jet velocities (near-sonic optimal), our nozzle jet has been designed for lower jet velocities to achieve low noise (jet noise varies to 1 / 10th of the nozzle velocity). When applied to the leading edge of a duct, the goal is to maximize the inflow overturn angle and prevent the leading edge of the duct from stalling.

[0122] In one embodiment, the circulating control duct can be applied to the duct leading edge 201 of any aircraft embodiment discussed herein.

[0123] The reference to "an embodiment" or "an embodiment" in the specification means that a particular feature, structure, or characteristic is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing in various parts of the specification does not necessarily refer to the same embodiment.

[0124] Although the invention has been specifically shown and described with reference to one embodiment and several alternative embodiments, those skilled in the art will understand that various changes in form and detail may be made herein without departing from the spirit and scope of the invention. [Simplified Explanation of the Diagram]

[0004] Figure 1 is a perspective view of a thruster fan according to one embodiment.

[0005] Figure 2A is a first exploded view of one of the propulsion fans according to one embodiment.

[0006] Figure 2B is a second exploded view of one of the propulsion fans according to one embodiment.

[0007] Figures 3A, 3B, 3C and 3D respectively illustrate a perspective view, a front view, a side view and a cross-sectional view of the leading edge of a duct of a propeller fan according to an embodiment.

[0008] Figures 4A, 4B, 4C and 4D respectively illustrate a perspective view, a front view, a cross-sectional view and a perspective view of a cross-section of a nose cone of a propeller fan according to an embodiment.

[0009] Figures 5A and 5B respectively illustrate a front view and a side view of a hub of a propeller fan according to one embodiment.

[0010] Figures 6A and 6B respectively illustrate a perspective view and a front view of a blade fan of a propeller fan according to an embodiment.

[0011] Figures 7A, 7B, 7C and 7D respectively illustrate a perspective view, a front view, a side view and a top view of one of the blades in a blade fan included in Figures 6A and 6B according to an embodiment.

[0012] Figures 8A, 8B and 8C respectively illustrate a perspective view, a front view and a side view of a locking ring of a propeller fan according to an embodiment.

[0013] Figures 9A and 9B respectively illustrate a perspective view and a side view of a tension ring of a propeller fan according to one embodiment.

[0014] Figures 10A, 10B and 10C respectively illustrate a perspective view, a front view and a side view of an inner duct housing of a propeller fan according to an embodiment.

[0015] Figures 11A, 11B, 11C and 11D respectively illustrate a perspective view, a front view, a side view and a cross-sectional view of a stator of a propeller fan according to an embodiment.

[0016] Figures 12A, 12B, 12C and 12D respectively illustrate a perspective view, a front view, a side view and a cross-sectional view of a tail cone of a propeller fan according to an embodiment.

[0017] Figures 13A, 13B and 13C respectively illustrate a perspective view, a front view and a side view of a circumferential drive system of a propeller fan according to an embodiment.

[0018] Figure 14 illustrates a circumferential drive system for a propeller fan according to another embodiment.

[0019] Figures 15A and 15B respectively illustrate a front view and a perspective view of a thruster fan array according to one embodiment.

[0020] Figure 16 illustrates an example application of a thruster fan array according to one embodiment.

[0021] Figures 17A, 17B and 17C respectively illustrate a front view, a side view and a top view of a hovering drone including a thruster fan array according to an embodiment.

[0022] Figures 18A, 18B and 18C respectively illustrate a front view, a side view and a top view of a movie drone including a thruster fan array according to an embodiment.

[0023] Figures 19A, 19B and 19C respectively illustrate a front view, a side view and a top view of a transport aircraft including a thruster fan array according to an embodiment.

[0024] Figures 20A, 20B and 20C respectively illustrate a front view, a side view and a top view of a vertical takeoff and landing (VTOL) aircraft including a propeller fan array according to one embodiment.

[0025] Figures 21A, 21B and 21C respectively illustrate a front view, a side view and a top view of a delivery drone including a thruster fan array according to an embodiment.

Claims

1. A method for operating a thruster fan, comprising: A thruster fan is provided, the thruster fan comprising: a first ring having a first diameter; a second ring having a second diameter larger than the first diameter; a plurality of twisted blades extending radially between and connected to the first and second rings, wherein the first and second rings tension the twisted blades such that a pitch of the blades during operation is substantially the same as a pitch of the blades when stationary, and wherein each twisted blade comprises: a first locking end connected to the first ring at a first angle; and a second locking end opposite the first end, comprising a blade tip and connected to the second ring at a second angle different from the first angle; and the thruster fan rotating at a blade tip speed of 300-450 feet per second to provide an ultrasonic blade passage frequency.

2. The method of claim 1, wherein the ultrasonic blade passes through a frequency between about 16,000 Hz and about 20,000 Hz.

3. The method of claim 1, wherein rotation of the propeller fan comprises rotating the propeller fan using a motor operating at about 20,000 RPM to about 40,000 RPM.

4. The method of claim 1, wherein each of the twisted blades is contained in a wing between the first locking end and the second locking end.

5. As in request item 1, where: Each of the twisted blades has a portion overlapping another portion of the twisted blades; and the twist of each of the twisted blades begins at a position of the twisted blade closer to the first ring than to the second ring.

6. The method of claim 1, wherein the propeller fan has a diameter between about 0.5 ft and about 5.5 ft.

7. The method of claim 6, wherein the propeller fan has a diameter between about 0.5 ft and about 1 ft.

8. The method of claim 1, wherein the twisted blades comprise 20 to 840 twisted blades.

9. The method of claim 8, wherein the twisted blades comprise 20 to 50 twisted blades.

10. The method of claim 1, wherein the first ring, the second ring, and the torsion blades are made of a composite material.

11. A propulsion fan comprising: A first ring having a first diameter; A second ring having a second diameter greater than the first diameter; a plurality of twisted blades extending radially between and connected to the first and second rings, wherein the first and second rings tension the twisted blades such that a pitch of the blades during operation is substantially the same as a pitch of the blades when stationary, wherein the twisted blades are configured to provide an ultrasonic blade passage frequency based on rotating the propeller fan at a blade tip speed of 300-450 feet per second, and wherein each of the twisted blades includes: a first locking end connected to the first ring at a first angle; and a second locking end opposite the first locking end, including a blade tip and connected to the second ring at a second angle different from the first angle.

12. The propulsion fan of claim 11, wherein the ultrasonic blade passes through a frequency between about 16,000 Hz and about 20,000 Hz.

13. The propeller fan of claim 11, wherein the plurality of torsional blades are configured to further provide the ultrasonic blades passing frequency by rotating the propeller fan via a motor operating at about 20,000 RPM to about 40,000 RPM.

14. The propulsion fan of claim 11, wherein each of the twisting blades is contained in a blade between the first locking end and the second locking end.

15. The thruster fan as described in request item 11, wherein: Each of the twisted blades has a portion overlapping another portion of the twisted blades; and the twist of each of the twisted blades begins at a position of the twisted blade closer to the first ring than to the second ring.

16. The thruster fan of claim 11, wherein the thruster fan has a diameter between about 0.5 ft and about 5.5 ft.

17. The propulsion fan of claim 16, wherein the propulsion fan has a diameter between about 0.5 ft and about 1 ft.

18. The propulsion fan of claim 11, wherein the plurality of twisted blades comprises 20 to 840 twisted blades.

19. The propulsion fan of claim 18, wherein the plurality of twisted blades comprises 20 to 50 twisted blades.

20. The propeller fan of claim 11, wherein the first ring, the second ring and the torsional blades are made of a composite material.

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