STRUCTURAL FEATURES OF VERTICAL TAKE-OFF AND LANDING (VTOL) AERIAL VEHICLE

Abstract

An aerial vehicle pertinent to the present application has a rotor system that operates in both a vertical-take-off-landing (VTOL) and a cruise mode. There are boom structures which support rotors and the tail. Tiltable rotors are located at the front ends of the booms. The rear rotors are placed under an upward rise in the booms, which allows for reduced in-flight drag and eliminates the need for collapsible rotors when said rotors are not actively operational.

Claims

1. An aerial vehicle comprising: a vehicle body; a first set of rotors, wherein the first set of rotors are configured to reside in a first position and a second position; and a second set of downward facing rotors, wherein the second set of downward facing rotors are configured to reside in a first state and a second state.

2. The aerial vehicle of claim 1 wherein the first position of the first set of rotors is in an upward facing position.

3. The aerial vehicle of claim 1 wherein the second position of the first set of rotors is in a forward-facing position.

4. The aerial vehicle of claim 1 wherein the first state of the second set of downward facing rotors is in an operative state.

5. The aerial vehicle of claim 1 wherein the second state of the second set of downward facing rotors is in a non-operative state.

6. The aerial vehicle of claim 1 further comprising a wing and a boom, wherein the boom is coupled to an underside of the wing.

7. The aerial vehicle of claim 6 wherein the boom has an upward rise at a trailing edge of the wing.

8. An aerial vehicle comprising: a vehicle body having a wing and a boom, wherein the boom has an upward rise at a trailing edge of the wing; a first set of rotors, wherein the first set of rotors are configured to reside in an upward facing and a forward-facing position; and a second set of downward facing rotors, wherein the second set of rotors are configured to reside at an apex of the upward rise in the boom.

9. The aerial vehicle of claim 8 wherein the boom comprises a first boom and a second boom.

10. The aerial vehicle of claim 9 wherein the first boom and the second boom are coupled via a tail.

11. The aerial vehicle of claim 8 wherein each of the first set of rotors and the second set of rotors has at least two blades.

12. The aerial vehicle of claim 8 wherein each rotor of the first set of rotors and the second set of rotors has two blades.

13. The aerial vehicle of claim 8 wherein a position of the second set of rotors is configured to reduce drag of the second set of rotors when not in use.

14. The aerial vehicle of claim 8 further comprising a coupling member configured to allow for rotation of the first set of rotors from an upward facing position to a forward-facing position.

15. An aerial vehicle comprising: a vehicle body having a wing and a boom, wherein the boom is coupled to an underside of the wing, and wherein the boom has an upward rise at a trailing edge of the wing; a first set of rotors rotatably coupled to the vehicle body via a coupling mechanism, wherein the first set of rotors are configured to reside in an upward facing and a forward-facing position; and a second set of downward facing rotors, wherein the second set of rotors are configured to reside at an apex of the upward rise in the boom, and wherein blades of the second set of downward facing rotors are configured to be aligned with the boom when not in use.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 illustrates a perspective view of an embodiment of the present application.

[0031] FIG. 2 illustrates a top view of an embodiment of the present application.

[0032] FIG. 3 illustrates a front view of an embodiment of the present application.

[0033] FIG. 4 illustrates a side view of an embodiment of the present application.

[0034] FIG. 5A illustrates an embodiment of the present application in a VTOL mode.

[0035] FIG. 5B illustrates an embodiment of the present application in a cruise mode.

[0036] FIG. 6A illustrates a wind tunnel simulation of surface air speed as applied to a known design, where rear rotors are place above the booms.

[0037] FIG. 6B illustrates a wind tunnel simulation of surface pressure as applied to a known design, where rear rotors are place above the booms.

[0038] FIG. 7A illustrates a wind tunnel simulation of surface air speed as applied to an embodiment of the present application.

[0039] FIG. 7B illustrates a wind tunnel simulation of surface pressure as applied to an embodiment of the present application.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The preferred embodiments of the present invention will now be described with reference to the drawings. Identical elements in the various figures are identified with the same reference numerals.

[0041] Reference will now be made in detail to each embodiment of the present invention. Such embodiments are provided by way of explanation of the present invention, which is not intended to be limited thereto. In fact, those of ordinary skill in the art may appreciate upon reading the present specification and viewing the present drawings that various modifications and variations can be made thereto.

[0042] Referring now to FIGS. 1-4, there are multiple views of an embodiment of the present invention embodied as an unmanned aerial vehicle or UAV 102. The UAV 102 generally has a vehicle body 104, first set of rotors 106, a second set of rotors 108, a wing 110, a tail 112, and a boom 114 comprised of a first boom 116 and a second boom 118.

[0043] The vehicle body 104 is configured to be aerodynamic and supports the wings 110 of the UAV 102. The exact shape and size of the vehicle body 104 and wings 110 may vary depending on the needs and qualities of the UAV 102 including but not limited to payload size/weight, range, materials used, velocity, and the like or some combination thereof. In at least one embodiment, the vehicle body 104 and wings 110 contain various sensors configured to sense at least one property of the environment in which the UAV 102 operates. The vehicle body 104 and the wings 110 may be formed from the same or a different material such as carbon fiber, polymers, metals, wood, composites, or some combination thereof. Further, the wings 110 may be separable from the vehicle body 104 or may be integral with the vehicle body 104.

[0044] The tail 112 and boom 114 form a separate subsection of the UAV 102 which may then be coupled to an underside of the wings 110 of the UAV 102. In a preferred embodiment, there is a first boom 116 and a second boom 118 coupled by the tail 112. Each of the first boom 116 and the second boom 118 are substantially identical to one another. Each of the first boom 116 and the second boom 118 are configured to support one rotor of each of the first set of rotors 106 and the second set of rotors 108.

[0045] On a first end of each of the first boom 116 and the second boom 118, there is at least one rotor. This rotor is configured to be rotatable between a first position and a second position, the first position being substantially parallel to the boom and the second position being substantially perpendicular to the boom as shown in FIGS. 5A and 5B.

[0046] To a rear of the wing 110 are the rotors forming the second set of rotors 108 with one rotor being disposed on each of the first boom 116 and the second boom 118. As shown in FIG. 4, there is an upward rise or kink in each of the first boom 116 and the second boom 118. The upward rise begins before the trailing edge of the wing 110 and continues past the trailing edge of the wing 110. In at least one embodiment, the upward rise starts at a midpoint between a leading edge and a trailing edge of the wing 110. As further described herein, particularly with reference to FIGS. 6A-7B, the upward rise functions as a fairing structure for the UAV 102.

[0047] At or near a second end of each of the first boom 116 and the second boom 118, the tail 112 emanates from a top surface of each of the first boom 116 and the second boom 118 thereby coupling the first boom 116 and the second boom 118. The tail 112 further aids in providing stability in flight.

[0048] Referring now to FIGS. 5A and 5B, shown are a UAV 102 in a take-off/landing configuration (FIG. 5A) and a flight or cruise configuration (FIG. 5B).

[0049] When in a take-off/landing configuration both the first set of rotors 106 and the second set of rotors 108 are actively operational or generating thrust. However, note that in this configuration, the first set of rotors 106 and the second set of rotors 108 are in opposing orientations. That is the first set of rotors 106 faces upwards and the second set of rotors 108 faces downwards. Further, it is of importance to note that each set of rotors and each rotor within the set of rotors may be independently controllable thereby allowing each rotor of the UAV 102 to generate the same or different thrust as another rotor of the UAV 102. This configuration allows for the UAV 102 to take-off or land vertically rather than having to utilize a runway or other method of gaining flight. Once landed, the rotors can be ceased to be used and the UAV 102 retrieved.

[0050] However, once the UAV 102 has taken-off, the first set of rotors 106 can be rotated from the vertical or parallel configuration to a horizontal or perpendicular configuration as shown in FIG. 5B. This allows for the thrust generated from the first set of rotors 106 to move the UAV forwards in flight while the wing 110 generates lift. The rotation from the vertical to horizontal positions may be achieved by a number of means and may utilize conventional motors such as a servo motor. Notably, when in this configuration, the second set of rotors 108 are stopped or cease to produce thrust as the fixed orientation of the rotors would not generate thrust conducive for flight. Further, the second set of rotors 108 are configured to, when in flight/cruise mode, align the at least two blades of each of the rotors of the second set of rotors 108 with the boom to which the rotor is coupled. For example, as shown in FIG. 5B, the blades of the second set of rotors 108 are in line with the length of the first boom 116 and second boom 118, respectively. Further, the position of the second set of rotors 108 “behind” the upward rise in the boom 114 reduces drag and increases other flight desirable qualities of the UAV 102.

[0051] Referring now to FIGS. 6A-7B, shown are data from a simulated wind tunnel testing of a conventional or known UAV (FIGS. 6A-6B) and data from a simulated wind tunnel testing of an embodiment of the present application (FIGS. 7A-7B). The parameters of each of the UAVs is shown below in Table 1.

TABLE-US-00001 TABLE 1 UAV of the Known UAV present application (FIGS. 6A-6B) (FIGS. 7A-7B) Length × Width × Height (cm) 68.1 × 119.4 × 15.7 67.3 × 119.4 × 18.5 Drag (N) 17.4 16.2 Lift (N) 251 265 Left (N) 1.15 0.4 Roll Moment (Nm) −0.08 0.06 Pitch Moment (Nm) 66.4 66.8 Yaw Moment (Nm) −0.09 −0.007

[0052] The data generated by the simulated wind tunnel shows the effects of drag on known UAVs and that of the present application. To generate the data, a commercial computational fluid dynamics software, MicroCFD® 3D Virtual Wind Tunnel, was used. As noted, this software was used to simulate the aerodynamics of two similar UAV models: 1) a conventional UAV design where rear rotors are placed on top of straight booms; and 2) an embodiment of the present application, where the rear (second set) of rotors are placed on an underside of the boom and behind an upward rise or kink in the boom structure. These two UAV models are of identical wingspan and fuselage, but the known UAV is slightly longer and the embodiment of the present application has a slightly higher tail, as dictated by the respective design differences between the UAVs.

[0053] As shown in FIGS. 6A-7B, the first set of rotors are removed, as such do not generate drag during cruise flight and are further not the subject of the present application. For the simulated wind tunnel simulation parameters, the air flow speed was set to 0.1 Mach (76.8 mile per hour), static air pressure was 1013 hPa, the temperature was 15 degrees Celsius, the gas constant was 287 Joule/(kilogram Kelvin), and the specific heat ratio was 1.4. FIGS. 6A-6B shows the air speeds (FIG. 6A) and pressure (FIG. 6B) near the surface of the known UAV. FIGS. 7A-7B shows the air speeds (FIG. 7A) and pressure (FIG. 7B) near the surface of the UAV subject to the present application.

[0054] In all of FIGS. 6A-7B, stream particle lines are displayed on a horizontal plane near the rear (second set) rotors. The stream particle lines in FIGS. 7A-7B indicates that the upward rise portion of the boom functions as a fairing structure for the rotors behind it. In addition, by comparing FIGS. 6B and 7B, it is apparent that the air pressure on the front surface of the rear rotors is higher in the known design than in the design of the present application. The data demonstrates the proposition that the upward rise in the boom design helps streamline portions of the aircraft. The force and moment calculated from these simulations are shown in Table 1 as well. Note that the total drag is 17.4 Newton for the known UAV, vs. 16.2 Newton for the UAV of the present application. In short, the UAV of the present application provides about a 6.9% reduction in total drag over known UAV design(s).

[0055] Although this invention and its embodiments have been described with a certain degree of particularity, it is to be understood that the present disclosure has been made only by way of illustration and that numerous changes in the details of construction and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.