VTOL propeller adapter and method

Abstract

In one possible embodiment, a propeller adapter is provided that includes a base having at least one fastener hole and a propeller alignment boss extending upwardly from the base. Opposing capture walls extend upwardly from the base, each having an inwardly extending lip for capturing and retaining a corresponding opposing outer edge of a propeller root portion therein when the propeller root portion is seated between the opposing blade capture walls.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 439,063, filed January 13, 2023, by Arbiv et al., entitled "VTOL PROPELLER ADAPTER AND METHOD," which is incorporated herein by reference in its entirety. [Background technology]

[0002] Vertical take-off and landing (VTOL) vehicles typically have detachable propellers that can be replaced if damaged or removed for storage and reattached for flight. For example, a conventional quad-rotor VTOL unmanned aerial vehicle (UAV) connects the propeller and motor with a screw located within the propeller along the central axis of rotation of the propeller and motor.

[0003] The motor center screw provides a way to ensure proper propeller alignment as well as clockwise / counterclockwise pairing of the propeller with its corresponding motor. This is achieved by matching the thread handedness of the propeller screw with the thread handedness of the motor rotor screw hole, thereby matching the propeller thread direction with the motor thread direction. This mechanism prevents improper installation, such as attaching a clockwise propeller to a counterclockwise motor, or vice versa.

[0004] While this configuration has its advantages, it also has some disadvantages. For example, if the screws are not properly fastened, they can come loose and damage the propeller, or the propeller can detach and cause a crash during flight. Additionally, VTOL UAVs typically have four or more propellers, which are removed after each flight for inspection and storage, increasing the chance of propeller damage when reattaching them for flight.

[0005] What is needed is a connection that ensures proper alignment of the propeller and pairing with the motor. Additionally, what is needed is a low-cost rigid connector that offers improved reliability and is easy and quick to install. Summary of the Invention

[0006] In one possible embodiment, a propeller adapter is provided that includes a base having at least one fastener hole and a propeller alignment boss extending upwardly from the base. Opposing capture walls extend upwardly from the base, each having an inwardly extending lip for capturing and retaining a corresponding opposing outer edge of a propeller root portion therein when the propeller root portion is seated between the opposing blade capture walls.

[0007] In a further embodiment, the propeller adapter further comprises a differentiation slot in at least one of the opposing blade capture walls and a propeller differentiation overlay for securing to the propeller, the propeller differentiation overlay having a differentiation tab extending laterally therefrom for aligning with and fitting within the slot in the at least one opposing blade capture wall.

[0008] In further embodiments, the alignment boss has an axially aligned central hole and is centrally disposed to center the propeller adapter over the central axis of the motor when attached to the motor. In some embodiments, the base and propeller differentiation overlay are color-coded to correspond to the direction of rotation of the motor and propeller. In some embodiments, the propeller adapter base and propeller differentiation overlay include lettering that corresponds to the direction of rotation of the motor. In some embodiments, the blade capture walls extend upwardly from opposing peripheral edges of the base.

[0009] In one possible embodiment, a VTOL-capable UAV is provided, including a motor, a propeller having an alignment hole extending through a root portion of the propeller, and a propeller adapter attached to the motor, the adapter having a base with at least one fastener hole extending therethrough to enable the adapter to be secured to the motor, an alignment boss extending upwardly from the base, opposing blade capture walls each having a lip for capturing and holding a corresponding outer edge of the propeller root when seated, at least one of the opposing blade capture walls having an alignment slot, and an alignment overlay secured to the propeller, the alignment overlay having a tab extending laterally therefrom to fit within the slot of at least one of the opposing blade capture walls.

[0010] Other embodiments are also provided. [Brief explanation of the drawings]

[0011] The features and advantages of the present invention will be better understood with reference to the following description, appended claims, and accompanying drawings. [Figure 1] FIG. 1 is a perspective view showing an example of a vertical take-off and landing (VTOL) capable unmanned aerial vehicle (UAV). [Figure 2] FIG. 2 is a perspective view showing a propeller adapter 200 according to an embodiment of the present invention. [Figure 3] FIG. 3 is a perspective view of a propeller differentiation overlay 300 according to at least one embodiment. [Figure 4] Figures 4A, 4B, and 4C are top perspective views of an embodiment of a CW propeller attached to a CW adapter, a CCW propeller attached to a CCW adapter, and a CW propeller improperly partially attached to a CCW adapter, respectively. [Figure 5] FIG. 5 is a cutaway top view of a propeller adapter according to some embodiments. [Figure 6]FIG. 6 is a side cross-sectional perspective view of a portion of a propeller mounted within a propeller adapter. [Figure 7] FIG. 7 is an exploded partial perspective view showing a possible embodiment of the configuration of the motor, propeller adapter, propeller, and propeller differentiation overlay. DETAILED DESCRIPTION OF THE INVENTION

[0012] In multi-propeller aircraft, motors are typically operated in clockwise (CW) and counterclockwise (CCW) directions. Therefore, in multi-propeller aircraft, the propeller blades orient differently depending on whether the propeller is rotating CW or CCW. Improper installation can render the aircraft unflyable. Removing an incorrectly installed propeller and reinstalling it in the correct orientation and position is time-consuming and can damage the aircraft during the removal and reinstallation of the propeller, and during subsequent operation after hastily reinstalling it.

[0013] FIG. 1 is a perspective view of an example vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) 100. In addition to a forward-facing propeller 110, there are four vertically oriented motors 120, 130, 140, and 150 with corresponding fixed-pitch propellers 125, 135, 145, and 155. Two of the motors, 120 and 140, have rotors that rotate clockwise or CW, while two motors, 130 and 150, rotate counterclockwise or CCW. Propellers 125 and 145, designed to rotate clockwise to provide lift, are attached to CW motors 120 and 140, respectively, while propellers 135 and 155, designed to rotate counterclockwise to provide lift, are attached to CCW motors 130 and 150, respectively. Adapters 200 (shown in FIG. 2) are used to attach the propellers 125, 135, 145, 155 to their respective motors 120, 130, 140, 150.

[0014] FIG. 2 is a perspective view of a propeller adapter 200 according to an embodiment of the present invention. The propeller adapter 200 includes a base 210 and a plurality of holes 212 extending through the base 210. The front or some of the threaded holes 212 extending through the base can be used to align and secure the adapter 200 to the motor, such as by fastening the base with screws (shown in FIG. 7). Some or all of the threaded holes 212, such as opposing pairs of threaded holes, may be positioned at different distances from the central rotational axis of the adapter 210. In this embodiment, an alignment boss 214 extends upward from a central portion of the base along the central rotational axis of the adapter 200. The alignment boss 214 is sized to fit within an alignment hole 625b (shown in FIG. 6) located in a root portion 652r of a propeller 625 (shown in FIG. 6) along the propeller's central axis of rotation.

[0015] In this embodiment, adapter 200 has opposing capture walls 216 and 218 located on opposite peripheries of base 210 and extending upwardly from base 210. The tops of capture walls 216 and 218 have inwardly extending lips 217 and 219, respectively, that extend inwardly of base 210. Inwardly extending lips 217 and 219 and capture walls 216 and 218 facilitate capturing and retaining the root portion of a propeller seated within the adapter.

[0016] 3 is a perspective view of a propeller handicapping overlay 300 according to at least one embodiment. The optional propeller handicapping overlay 300 is attached to a propeller to indicate the propeller's handedness, inhibiting the installation of an incorrect propeller into an adapter with the wrong thread orientation and preventing the installation of an incorrect propeller on a motor. The handicapping overlay 300 may include one or more handicapping tabs 301 and / or 303 configured to correspond to one or more alignment slots 202 and / or 204 ( FIG. 2 ) on the adapter 200. The bottom 303 b of the handicapping tabs 301 and / or 303 may be tapered to facilitate alignment and installation of the handicapping tabs 301 and / or 303 within the alignment slots 202 and 204.

[0017] In some embodiments, alignment slots 202 and 204 may have the same width. Alternatively, in some embodiments, alignment slots 202 and 204 may have different widths to ensure proper orientation of the propeller within the adapter. The widths of differentiation tabs 301 and 303 may likewise be the same or different widths to match the slots.

[0018] The propeller differentiation overlay 300 can be affixed to the propeller with adhesive or the like, so that for a propeller with a corresponding propeller differentiation overlay 300 on the adapter, differentiation tabs 301 and 303 fit into alignment slots 302 and 304, allowing the propeller to be attached within the adapter. The placement of alignment slots 302, 304 and differentiation tabs 301, 303 depends on whether a CW motor and propeller is being used with a CCW motor and propeller. If differentiation tabs 301, 303 do not align with alignment slots 302, 304, the differentiation tabs 301, 303 and the attached propeller are blocked and cannot be attached within the adapter 200 (FIG. 2). This ensures that both the propeller to which the overlay is affixed and the associated motor to which the adapter 300 is attached have the same thread direction (CW or CCW).

[0019] As shown in FIGS. 2 and 3, the adapter 200 and the differentiation overlay 300 may have a letter 305, such as an "A," or one or more other letters marked, painted, engraved, and / or indented on or in the differentiation overlay 300 (as shown in FIG. 3). Although not shown in FIG. 2, the adapter 200 preferably has a corresponding letter, mark, paint, engraved, and / or indentation as well. Additionally or alternatively, the adapter 200 and the differentiation overlay 300 may be patterned or color-coded, i.e., the same or a similar color or pattern, to indicate compatibility between the adapter 200 and the overlay 305, thereby ensuring rotational compatibility between the motor and the propeller. In another embodiment, even if the adapter 200 and the overlay 305 are the same color, the letter marking "A" has the same or a similar color to indicate compatibility. This allows for quick and easy visual confirmation that the adapter 200 and the overlay 305 are compatible before selecting and attaching a propeller to the motor. Therefore, when selecting the appropriate propeller, after selecting the propeller, just before installing the propeller, and during the propeller installation process, the propeller and the motor to which the adapter is attached are both indicated as being rotationally compatible (CW or CCW). For example, the letter "A" can be used to indicate CW rotation and the letter "B" can be used to indicate CCW rotation.

[0020] 4A is a top perspective view of one embodiment of a CW propeller 425 attached to a CW adapter 410. In this embodiment, the identification tabs 401 of the CW identification overlay 430 fit within the alignment slots 402 of the CW adapter 410.

[0021] 4B is a top perspective view of one embodiment of a CCW propeller 425ccw attached to a CCW adapter 410ccw, in which the identification tabs 401ccw of the CCW identification overlay 430ccw fit within the alignment slots 402ccw of the CCW adapter 410ccw.

[0022] 4C is a top perspective view of an embodiment of a CW propeller 425cw improperly partially attached to a CCW adapter 410ccw. In this embodiment, the identification tab 401cw of the CW identification overlay 430cw does not fit within the alignment slot 402ccw of the CWW adapter 410ccw. This prevents incorrect attachment of the CCW propeller 425cw to a CCW motor because the identification tab 401cw of the CW identification overlay 430cw attached to this CW propeller 425cw will not be able to attach to the CCW alignment slot 402ccw of an incompatible CCW adapter 410ccw attached to a CCW motor. In this way, the misalignment of the identification tab 410cw with the alignment slot 402ccw prevents the propeller 425cw from being properly attached, indicating to the installer that the propeller 425cw and the motor are rotationally mismatched. In some embodiments, attempting to attach a CW propeller 425cw to a CCW adapter 410ccw may damage or break the CW differentiation tab 401cw or cause the CW differentiation overlay 430cw to separate from the CW propeller 425cw, thereby indicating to the installer that an inappropriate propeller is attached to a rotationally mismatched motor.

[0023] FIG. 5 is a cutaway top view of a propeller adapter 510 according to some embodiments. In this embodiment, there is an additional boss 513 laterally spaced from the central alignment boss 514. The optional additional laterally offset boss 513 is a pin that extends upward from the base of the propeller adapter 510 and fits into a corresponding hole (e.g., lateral hole 625h in FIG. 6) in the propeller 625 shown in FIG. 6. The optional offset boss 513 provides an additional alignment post and provides additional rotational stability when mounting the propeller. Like the central boss 514, the optional offset boss 153 may have other configurations, such as a cylindrical shape with or without a rounded top, a notched cylindrical shape, a partial cylindrical shape, or combinations thereof, or a conical or partial conical shape, to facilitate propeller placement and installation of the boss into the corresponding hole in the propeller. It should be noted that in some embodiments, the central alignment boss 514 can be omitted. In such an embodiment, the offset boss 513 can provide for proper alignment of the propeller within the propeller adapter 510.

[0024] Some embodiments can further include an optional integrally formed locking tab 519t that extends beyond the lip 517 of the side wall of the adapter 510. The locking tab 519t can snap down into place on the propeller once the propeller is installed in the adapter. In some embodiments, the locking tab 519t can lock with a corresponding optional integrally formed extending locking tab (not shown) that extends from the opposite side wall of the adapter 510 to engage with the locking tab 519t on the propeller.

[0025] 6 is a side cross-sectional perspective view of a portion of a propeller 625 mounted within a propeller adapter 610. The propeller adapter 610 is attached to a motor hub 620h. The hub boss pin 622 fits within a bore hole 614b in an adapter alignment boss 614. The adapter alignment boss 614 fits partially, as shown, or completely in some embodiments, within a propeller central alignment hole 625b. The alignment boss 614 is sized to fit within the alignment hole 625b located at a root portion 652r of the propeller 625 aligned along the propeller's central axis of rotation.

[0026] Propeller 625 is attached to the adapter by a snap fit, with inwardly facing rims or lips 617 and 619 contacting and retained beneath corresponding edges 625e. Rims 617 and 619 extend far enough to fit beneath the propeller when attached, and to form an interference fit over the upturned portion of the rounded edge of the propeller root with sufficient force to prevent the propeller from disengaging as the propeller rotates and the aircraft maneuvers in its normal flight profile.

[0027] 7 is a partially exploded perspective view of one possible embodiment of how a motor 720, propeller adapter 710, propeller 725, and propeller differentiation overlay 730 may be arranged. In the illustrated embodiment, the propeller adapter 710 is attached to a hub portion 720h of a rotor 720r of an outrunner motor 720. In some embodiments, a hub boss pin 722 is located in the center of the hub portion 720h of the rotor 720r. In this embodiment, the adapter alignment boss 714 has a hole or bore 714b extending partially or completely through the adapter alignment boss 714 and sized to receive the hub boss pin 722. The hub boss pin 722 in the alignment boss hole 714b serves to align the propeller adapter 710 on the central rotational axis of the motor 720. Preferably, hub boss pin 722 fits securely within alignment boss hole 714b to prevent translational movement of adapter 710 attached thereto, yet allows adapter 710 to be removed from hub boss pin 722 for maintenance.

[0028] One or more screws 713 thread into threaded holes 723 in the rotor hub 720h to secure the adapter 710 to the rotor 720r and keep the adapter 710 aligned with the central axis of rotation of the motor 720r. Typically, the screw holes are countersunk so that the screw head is flush with the top surface of the adapter's base. In embodiments without a hub boss pin 722, multiple screws 713 are seated within the threaded holes 723 and serve to align the adapter 710 with the central axis of rotation of the rotor 720r.

[0029] After the propeller adapter 710 is attached to the motor 720, the propeller 725 is snap-fitted onto the propeller adapter 710 at the root portion 725r of the propeller 725. The outer edge 725e of the root portion 725r is securely clamped and held securely by the propeller adapter 710 when attached. The outer edge 725e of the root or hub portion of the propeller is radiused. The rounded radial cross-section of the edge of the propeller hub portion facilitates snap-fitting the propeller onto the adapter 710.

[0030] The adapter 710 is configured to allow a person to easily attach and detach the propeller 725 to and from the adapter 710 by hand without the need for tools. In some embodiments, the adapter is formed from a polyaryletherketone (PAEK) such as polyetheretherketone (PEEK). Other organic thermoplastic polymers can also be used. In other embodiments, other materials such as Delrin (homopolymer acetal or POM-H), ABS (acrylonitrile butadiene styrene), polycarbonate (POLYCARB), or ULTEM (polyetherimide or PEI) can be used depending on the application. Natural-color PEEK has the advantage of being rigid enough to hold the propeller in place during UAV operation, while being flexible enough to allow the propeller to be repeatedly attached and detached from the adapter by hand. It is anticipated that other materials with mechanical properties similar to PEEK may also be utilized. In some embodiments, the adapter is fabricated from unreinforced PEEK using thermoplastic molding techniques. In some embodiments, depending on the application, it may be desirable to use 3D printing, machining techniques, or reinforced PEEK, which is commercially available, for example, from Curbell Plastics, Inc., Orchard Park, NY (www.curbellplastics.com).

[0031] Alignment tabs 701 of differentiation overlay 730 fit into corresponding alignment slots 702 of propeller adapter 710. In this embodiment, alignment slots 702 have rounded bottom walls. The generally tapered shape of alignment tabs 701 that fit into alignment slots 702 results in the bottom walls of slots 702 being rounded rather than flat. Additionally, the rounded bottom walls provide increased structural strength compared to the angular bottom walls shown in FIG. 2, reducing cracking of the side walls of propeller adapter 710. This increases the robustness of the side walls where high forces are applied.

[0032] As shown in FIG. 7, the letter "A" may be color-coded to visually indicate that the motor and propeller rotation directions correspond. Furthermore, as shown in FIG. 7, the alignment tabs 701 and alignment slots 702 correspond in position, allowing the propeller 725 to be installed within the adapter 710 if the motor and propeller 725 rotation directions match, preventing the installation of an incorrect propeller on the wrong motor. The alignment tabs 701 cooperate with the alignment slots 702 to prevent the installation of an incorrect propeller. Therefore, in low lighting conditions or when the propeller installer is unable to distinguish colors due to color blindness, the combination of the propeller adapter 710 and the propeller differentiation overlay ensures that the correct propeller is installed on the correct motor. This is particularly important when multiple motors, including motors with opposite rotation directions, are installed on the same aircraft.

[0033] In some embodiments, the adapter alignment boss 714r may have a radiused or rounded top to facilitate the installation of the propeller alignment hole 625b (shown in FIG. 6 ) into the adapter alignment boss 714 when the propeller 725 snaps into the adapter 710. Thus, rather than a right-angled shape or cross-section, the cylindrical alignment boss 714 may have a radiused or rounded top periphery 714r around the circumference of the cylindrical alignment boss 714. While the propeller root 725 may be pressed flat into the adapter 710, in another embodiment, the propeller root 725 is installed into the adapter 710 by fitting one of the outer edges 725e of the propeller root 725 into the adapter 710 and then screwing the propeller root 725 until the other outer edge 725e clicks into place within the adapter 710. In this way, the root portion 725r of the propeller 725 is seated and held within the adapter 710 in a state where the root portion 725r is aligned with the central rotational axis of the motor in the direction of rotation.

[0034] Because rotational loads are exerted on the outer edge 725e of the propeller 725, the walls 216 and 218 (FIG. 2) must be sufficiently rigid to withstand these loads. As shown in FIG. 2, in some embodiments, the wall 216 may have a rounded "corner" seam 216c where the inward-facing side of the wall 216 attaches to the base 210. In some embodiments, a relief fillet is added to the seam 216c between the wall 215 and the base 210 to increase the radius of the material along the corner seam 216c between the wall and the base 210. In this manner, stress-relieving material is added to reinforce the corner seam 216c and form a gusset that prevents cracking or splitting between the wall 215 and the base 210. A similar rounded corner seam is present between the side wall 216 and the lip 217, and similar additional material may also provide reinforcement along the seam. 2, walls 216 and 219 each have four sections, including a lower radius between a generally straight middle section and an upper radius, which is located between the generally straight or middle section and lips 217 and 219. Thus, in various embodiments, side walls 216 and 219 can repeatedly flex outward as the propeller snaps into the adapter and then spring back inward as the propeller seats against the base in the adapter, thereby holding the propeller in place relative to the base during operation but allowing the propeller to be manually removed before or after operation.

[0035] In the embodiment shown in FIG. 6, lips 617 and 619 are shown extending to and engaging the rounded or radiused edge 625e of root 625r of propeller 625, although in other embodiments one or more of lips 617 and 619 may extend beyond the radiused edge onto the flat surface on top of root 625r.

[0036] The advantage of limiting the length of the lip extension as shown is that it provides greater robustness and allows for quick and easy insertion and removal of the propeller by hand, without the need for tools or excessive force. Thus, to manually engage a propeller into an adapter, one hub edge is inserted under one lip of the adapter, and the propeller is rotated along its longitudinal axis, causing the other edge of the root section to rotate and contact the opposite lip, deflecting the lip (and walls) outward until the farthest portion of the hub edge slides past the lip, after which the lip deflects inward, allowing the propeller hub to fit under the lip and into the adapter. To remove the propeller, the propeller is rotated along its longitudinal axis, forcing the hub edge upward against the lip, forcing the lip (and walls) outward in accordance with the curvature of the hub edge, causing the farthest portion of the hub edge to slide upward past the lip, releasing the propeller hub from the adapter.

[0037] In various embodiments, the inwardly facing peripheral edge of the lip may be partially or fully radiused or rounded so as to slide over the radiused or rounded edge of the hub during the snap fit installation and removal process.

[0038] In various embodiments, the adapter material is sufficiently flexible and resilient to allow the propeller to be attached and detached multiple times (e.g., about 25, 50, 100, 200, or more), while being strong and rigid enough to retain the propeller under normal dynamic aircraft maneuvers within the aircraft's flight envelope.

[0039] An advantage of some embodiments is that they provide a robust connection between the propeller and the motor with minimal backlash over the entire usable temperature range. Another advantage of various embodiments is that they provide a robust, low-cost, rigid connection between the propeller and the motor.

[0040] An advantage of various embodiments is that the distinguishing overlay or positioning disk can prevent a user from attaching the wrong propeller to the wrong motor. This is particularly important for VTOL quad-motor UAVs, which have two CW and two CCW motors and propellers. In some embodiments, the distinguishing overlay or positioning disk may be color-paired with a corresponding adapter. In some embodiments, an interference structure prevents improper installation.

[0041] An advantage of various embodiments is that they reduce the time required to install a propeller onto a rotationally matched motor. Such embodiments not only speed installation, but also reduce the time required to remove the propeller. An advantage of the snap-fit ​​feature of various embodiments is that it allows for a rigid, carbon fiber-plastic-aluminum interface between the propeller blades, adapter, and motor, respectively.

[0042] While FIG. 1 illustrates one forward-facing propeller and four upward-facing propellers, other embodiments are not limited to this configuration. For example, in some embodiments, the forward-facing motor and propellers may be omitted. Still other embodiments may have more or fewer vertically oriented motors and propellers. In some embodiments, propellers 125, 135, 145, and 155 may have a fixed pitch, while in other embodiments, the propellers have an adjustable rotational pitch. Furthermore, while a one-piece propeller is illustrated, it is contemplated that the hub portion and propeller blades may be separate pieces, i.e., the blade portion may fold relative to the hub portion of the propeller, typically along the horizontal plane of the hub.

[0043] Although illustrated in the context of a UAV, embodiments of the present invention are not limited to UAVs. Furthermore, not all components are required in all embodiments. The apparatus, methods, and systems described above are not limited to UAVs or aircraft. Various implementations and / or embodiments may include other motor applications, i.e., automotive, industrial, etc., that replace traditional motor attachment mounting.

[0044] It should be noted that a reference to "one embodiment" or "one example" means that the particular features, structures, or characteristics described in connection with that embodiment may be included in the embodiment, as appropriate. The appearances of the phrase "in one embodiment" in various places in this specification do not necessarily all refer to the same embodiment.

[0045] The illustrations and examples provided herein are for illustrative purposes only and are not intended to limit the scope of the appended claims. The present disclosure is to be considered an exemplification of the principles of the invention and is not intended to limit the spirit and scope of the invention to the illustrated embodiments and / or the scope of the claims.

[0046] Those skilled in the art will be able to adapt the invention for their particular use.

[0047] The discussion contained in this patent is intended to serve as a basic description. The reader should note that a particular description may not explicitly describe every possible embodiment and may implicitly include alternatives. Furthermore, the description may not fully describe the general nature of the invention and may not explicitly show how each feature or element may actually be a representative element or equivalent element. Again, these are implicitly included in the disclosure. When the invention is described in device-oriented terms, each element of the device implicitly performs a function. It should also be understood that various modifications are possible without departing from the essence of the invention. Such modifications are implicitly included in the description. These modifications are also within the scope of the invention.

[0048] Furthermore, each element of the invention and claims may be implemented in a variety of ways. This disclosure should be understood to encompass each such variation, whether it be a variation of an apparatus embodiment, a variation of a method embodiment, or simply a variation of these elements. In particular, since this disclosure is directed to elements of the invention, it should be understood that the words for each element may be expressed in equivalent apparatus terms, even if the function or result is the same. Such equivalent, broader, or more general terms should be considered to be encompassed in the description of each element or act. Such terms can be substituted as necessary to make clear the broad scope implicit in the invention. It should be understood that all acts can be expressed as a means for performing that act or as an element that causes that act. Similarly, each physical element disclosed should be understood to encompass a disclosure of the act that the physical element performs. Such variations and alternative terms are understood to be expressly included herein.

[0049] While the present invention has been described in connection with several embodiments, modifications of the present invention will no doubt now occur to those skilled in the art. The illustrative embodiments herein are not intended to be limiting, as various configurations and feature combinations are possible. Thus, the present invention is not limited to the disclosed embodiments, except as required by the appended claims.

Claims

1. In the propeller adapter, a) a base, 1) at least one fastener hole therethrough; 2) a propeller alignment boss extending upwardly from the base; b) opposing capture walls extending upwardly from the base, each having an inwardly extending lip for capturing and retaining a corresponding opposing outer edge of the propeller root portion when the propeller root portion is received between the opposing blade capture walls.

2. 10. The propeller adapter of claim 1, further comprising: a) a differentiation slot in at least one of the opposing blade capture walls; 2. The propeller adapter of claim 1, further comprising: b) a propeller differentiation overlay for securing to the propeller, the propeller differentiation overlay having differentiation tabs extending laterally therefrom that align with and fit within slots in at least one of the opposing blade capture walls.

3. 3. The propeller adapter of claim 2, wherein the alignment boss further includes an axially aligned central bore, the alignment boss being located at the center of the propeller adapter to center the propeller over the central axis of the motor when the motor and propeller are attached.

4. 2. The propeller adapter of claim 1, wherein the base and propeller differentiation overlay are color-coded to correspond to the direction of rotation of the motor and propeller.

5. 2. The propeller adapter of claim 1, wherein the propeller adapter base and the propeller identification overlay include lettering corresponding to a direction of rotation of the motor.

6. The propeller adapter of claim 1 , wherein the blade capture walls extend upwardly from opposed peripheral edges of the base.

7. 2. The propeller adapter of claim 1, wherein the alignment boss further includes an axially aligned central bore, the alignment boss being located at the center of the propeller adapter such that the alignment boss is aligned with a central axis of the motor when the propeller adapter is attached to the motor.

8. In VTOL-compatible UAVs, a) a motor; b) a propeller having an alignment hole extending through a root portion of the propeller; c) a propeller adapter attached to the motor, 1) At the base, (i) at least one fastener hole therethrough for securing the adapter to the motor; (ii) a base having an alignment boss extending upwardly from the base; 2) opposing blade capture walls extending upwardly from the base, each having a lip for capturing and holding a corresponding outer edge of the propeller root when the propeller root is positioned between the opposing blade capture walls; 3) an alignment slot in at least one of the opposing blade capture walls; d) an alignment overlay secured to the propeller, the alignment overlay having tabs extending laterally from the overlay to fit within slots in at least one of the opposing blade capture walls.

9. 9. The VTOL-capable UAV of claim 8, wherein the propeller alignment hole is located at the center of the propeller root and the alignment boss is located at the center of the adapter to center the propeller over the motor central axis.

10. 10. The VTOL-capable UAV of claim 9, wherein the propeller has a plurality of alignment holes at a root portion of the propeller, and the propeller adapter has a plurality of alignment bosses disposed on the adapter corresponding to the plurality of alignment holes for centering the propeller above the central axis of the motor.

11. 9. The VTOL-capable UAV of claim 8, wherein the alignment holes include a plurality of spaced apart alignment holes in a root portion of the propeller, and the alignment bosses include a plurality of alignment bosses corresponding to a plurality of alignment holes in the propeller for centering the propeller above the central axis of the motor.

12. 9. The VTOL-capable UAV of claim 8, wherein the propeller has a plurality of alignment holes at a root portion of the propeller, and the propeller adapter has a plurality of alignment bosses disposed on the adapter corresponding to the plurality of alignment holes for centering the propeller above the central axis of the motor.

13. 9. The VTOL-capable UAV of claim 8, wherein the propeller adapter includes an alignment slot in each of the opposing blade capture walls, and the alignment overlay includes a plurality of tabs extending therefrom to fit into corresponding ones of the alignment slots in each of the opposing blade capture walls.

14. 9. The VTOL-capable UAV of claim 8, wherein the motor is an outrunner motor comprising an outrunner rotor surrounding an inner stator, and the propeller adapter is attached to the outrunner rotor.

15. 9. The VTOL-capable UAV of claim 8, wherein the motor is an inrunner motor comprising an inrunner rotor surrounded by an outer stator, and the propeller adapter is coupled to the inrunner rotor.

16. 9. The VTOL-capable UAV of claim 8, wherein the alignment boss further has an axially aligned central hole, the alignment boss being located at the center of the propeller adapter to center the propeller above the central axis of the motor when the motor and propeller are attached.

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