阅读说明：本技术 垂直起降m形机翼构型 (Vertical take-off and landing M-shaped wing structure ) 是由 马克·穆尔 约翰·巴达拉门蒂 伊恩·维拉 亚当·瓦莫特 大卫·约瑟夫森 于 2018-11-03 设计创作，主要内容包括：垂直起降(VTOL)飞行器从垂直起飞状态过渡至巡航状态,其中垂直起飞状态使用螺旋桨来产生升力,且巡航状态使用机翼来产生升力。该飞行器具有M形机翼构型,其中螺旋桨位于翼梢吊舱、机翼吊杆和尾部吊杆上。机翼吊杆和/或尾部吊杆可以包括吊杆控制执行器。机翼、尾部吊杆和尾部上的铰接的控制表面在起飞和降落期间倾斜以使交通工具偏航。吊杆控制执行器、巡航螺旋桨、堆叠式螺旋桨和控制表面在不同的操作模式期间可以具有不同的位置,以控制飞行器的运动并减轻由飞行器产生的噪声。(A vertical take-off and landing (VTO L) aircraft transitions from a vertical take-off state to a cruise state, where the vertical take-off state uses propellers for generating lift and the cruise state uses wings for generating lift.)

1. A stacked propeller comprising:

a first propeller comprising two blades coupled to a first blade hub, the first propeller configured to rotate about an axis of rotation;

a second propeller comprising two blades coupled to a second blade hub, the second propeller configured to rotate about the axis of rotation and located aft of the first propeller such that fluid displaced by the first propeller is incident on the second propeller; and

at least one motor configured to rotate the first and second propellers, wherein the first and second propellers rotate together about the axis of rotation.

2. The stacked propeller of claim 1, wherein the first propeller and the second propeller are separated by an azimuth angle, and wherein the azimuth angle is variable during different modes of operation.

3. The system of claim 2, further comprising:

a clutch configured to control the azimuth angle, wherein the azimuth angle is constant during one mode of operation.

4. The system of claim 1, wherein the first propeller and/or the second propeller are configured to retract along the axis of rotation and recess into a cavity during an operating mode.

5. The system of claim 1, wherein the first propeller and the second propeller rotate at the same speed during a first mode of operation and rotate at different speeds during a second mode of operation.

6. The system of claim 1, wherein the at least one motor comprises a first motor and a second motor configured such that in a first mode of operation, the first motor rotates the first propeller and the second motor rotates the second propeller.

7. The system of claim 5, wherein the first and second motors are further configured such that in a second mode of operation, the first motor rotates the first and second propellers or the second motor rotates the first and second propellers.

8. The system of claim 1, wherein the blades of the first propeller and the blades of the second propeller have the same shape.

9. The system of claim 1, wherein the first propeller and the second propeller are enclosed by a duct.

10. The system of claim 1, wherein a pitch of the blades of the first propeller is different than a pitch of the blades of the second propeller.

11. The system of claim 1, wherein the diameter of the second propeller is smaller than the diameter of the first propeller.

12. The system of claim 1, wherein the free end of the blade rotates at a maximum speed of 450 feet per second.

13. An aircraft, comprising:

a port-stacked propeller including a first pair of co-rotating propellers; and

a starboard stacked propeller including a second pair of co-rotating propellers,

wherein the starboard stacked propeller is configured to rotate in a direction opposite to a rotation direction of the port stacked propeller.

14. The system of claim 13, wherein the first pair of co-rotating propellers comprises a first propeller and a second propeller each comprising two blades coupled to a blade hub and configured to rotate about a common axis of rotation.

15. The system of claim 14, wherein the blades of the first propeller and the blades of the second propeller have a fixed pitch.

16. The system of claim 14, wherein the first propeller is configured to retract along an axis of rotation and recess into a cavity during one mode of operation.

17. The system of claim 14, wherein the first propeller and the second propeller are separated by an azimuth angle, and wherein the azimuth angle is variable in different modes of operation.

18. The system of claim 17, further comprising:

a clutch configured to control the azimuth angle, wherein the azimuth angle is constant during one mode of operation.

19. The system of claim 14, further comprising a first motor to rotate the first propeller and a second motor to rotate the second propeller.

20. The system of claim 14, wherein the diameter of the second propeller is smaller than the diameter of the first propeller.

21. An aircraft having a center of gravity, the aircraft comprising:

a fuselage having at least one passenger seat;

an M-shaped wing mounted to the fuselage, the M-shaped wing having a port portion and a starboard portion, the port and starboard portions each including a first section extending outwardly from the fuselage to an inflection point and a second section extending outwardly from the inflection point, wherein the first and second sections are connected at a non-zero angle at the inflection point;

a tail region extending from the fuselage; and

a set of propellers configured such that a vertical center of thrust is substantially aligned with a center of gravity during one mode of operation, the set of propellers including a first propeller coupled to the port portion of the M-shaped wing, a second propeller coupled to the starboard portion of the M-shaped wing, and a third propeller coupled to the tail region.

22. The aircraft of claim 21, further comprising:

a first wing boom attached to the port portion of the M-shaped wing near the inflection point; and

a second wing boom attached to the starboard portion of the M-shaped wing near the inflection point,

wherein the tail region comprises a tail boom.

23. The aerial vehicle of claim 22 wherein at least one of the first wing boom, the second wing boom, or the tail boom attached comprises a boom control actuator configured to direct airflow generated by a propeller.

24. The aerial vehicle of claim 22 wherein at least one of the first wing boom, the second wing boom, or the tail boom is hollow and is configured as a resonator tuned to a frequency of a propeller during the mode of operation.

25. The aerial vehicle of claim 22 wherein at least one of the first wing boom, the second wing, or the tail boom is configured to hold a battery.

26. The aerial vehicle of claim 22 wherein the first propeller is attached to the first wing boom aft of the M-wing and the second propeller is attached to the second wing boom aft of the M-wing.

27. The aerial vehicle of claim 26 wherein the first and second propellers are located forward of the center of gravity of the aerial vehicle.

28. The aerial vehicle of claim 21 wherein the first, second, and third propellers each comprise a set of co-rotating propellers.

29. The aircraft of claim 21, further comprising:

a fourth propeller attached to the tail region of the aircraft, wherein during the operational mode the fourth propeller rotates in a direction opposite to a direction of rotation of the third propeller.

30. The aircraft of claim 21 wherein the non-zero angle is in a range from five to twenty-five degrees.

31. The aircraft of claim 21, further comprising:

a fifth propeller attached to a first pod at a free end of the starboard portion of the M-shaped wing; and

a sixth propeller attached to a second pod at a free end of the port portion of the M-shaped wing.

32. The aircraft of claim 21 wherein the first and second pods are configured to be perpendicular to the fuselage during the operational mode and parallel to the fuselage during a second operational mode.

33. The aerial vehicle of claim 31 wherein during said mode of operation, said fifth propeller rotates in a direction opposite to the rotation of said sixth propeller.

34. The aircraft of claim 21 wherein the total area of the disks of the set of propellers results in a disk load of less than 15.

35. The aircraft of claim 21, wherein the tail region comprises a T-shaped tail having a straight tail with a rudder configured to control yaw motion of the aircraft and a tailplane vertically attached to the straight tail.

36. The aircraft of claim 35 wherein the tailplane includes a tail control surface configured to rotate about an axis parallel to the tailplane to control pitch of the aircraft.

37. The aerial vehicle of claim 21 wherein the first, second, and third propellers are configured to be recessed within an interior cavity of the aerial vehicle during a second mode of operation.

38. The aerial vehicle of claim 21 wherein during said mode of operation, said first propeller rotates in a direction opposite to a direction of rotation of said second propeller.

39. The aircraft of claim 21, further comprising four seats arranged within the fuselage in two rows oriented such that the rows of seats face each other, wherein the two rows are arranged in tiers such that one row of seats is elevated above the other row of seats.

40. The aircraft of claim 21, further comprising:

a first motor coupled to the first propeller;

a second motor coupled to the second propeller; and

a third motor coupled to the third propeller.

41. A system, comprising:

a propeller coupled to a rotor shaft, wherein the propeller rotates about an axis of rotation, thereby generating an airflow; and

a boom control actuator coupled to the rotor mast at a location at least partially within the airflow generated by the propeller, wherein the boom control actuator rotates about an axis perpendicular to the axis of rotation to redirect at least a portion of the airflow in a desired direction.

42. The system of claim 41, wherein the rotor mast is a boom of an aircraft.

43. The system of claim 42, wherein the boom holds a motor.

44. The system of claim 41, wherein said boom control actuator redirects said airflow toward a resonator to reduce noise generated by said propeller during one mode of operation.

45. The system of claim 44, wherein the boom control actuator oscillates at an adjusted frequency to reduce noise generated by the propeller in cooperation with the resonator.

46. The system of claim 41, wherein the boom control actuator rotates-45 degrees to 45 degrees relative to an axis perpendicular to the axis of rotation.

47. The system of claim 41, wherein the boom control actuator is coupled to an electric motor.

48. The system of claim 41 wherein said boom control actuator has a rounded end region coupled to said rotor mast and a pointed free end region.

49. The system of claim 41, wherein the boom control actuator redirects the airflow in a direction to control a yaw moment of the aircraft during one mode of operation.

50. The system of claim 41, wherein the boom control actuator comprises a first component and a second component, wherein during one mode of operation, the first component rotates about a first axis perpendicular to the axis of rotation and the second component rotates about a second axis perpendicular to the axis of rotation.

51. An aircraft, comprising:

a propeller coupled to an aircraft boom, wherein the propeller rotates about an axis of rotation, thereby generating an airflow; and

an aircraft boom, wherein the boom comprises a boom control actuator coupled to the aircraft boom at a location at least partially within the airflow generated by the propeller, wherein the boom control actuator rotates about an axis perpendicular to the axis of rotation to redirect at least a portion of the airflow in a desired direction.

52. The aircraft of claim 51 wherein the aircraft boom is located on an aft portion of the aircraft.

53. The aircraft of claim 51, wherein the aircraft boom is located on a wing of the aircraft.

54. The aircraft of claim 51 wherein the aircraft boom is hollow.

55. The aircraft of claim 51 wherein the boom control actuator redirects the airflow toward a resonator during one mode of operation to reduce noise.

56. The aerial vehicle of claim 15 wherein said boom control actuator oscillates at an adjusted frequency to cooperate with said resonator to reduce noise generated by said propeller.

57. The aircraft of claim 51 wherein the free end of the boom control actuator is pointed.

58. The aircraft of claim 51 wherein the boom control actuator redirects the airflow in a direction to control a yaw moment of the aircraft during one mode of operation.

59. The aerial vehicle of claim 51, wherein said aerial vehicle boom holds a motor, and wherein said boom control actuator is coupled to said motor.

60. The aircraft of claim 51 wherein the boom control actuator comprises a first component and a second component, wherein the first component rotates about a first axis perpendicular to the axis of rotation and the second component rotates about a second axis perpendicular to the axis of rotation.

Technical Field

The described subject matter relates generally to the field of air transportation and, more particularly, to a vehicle for vertical take-off and landing that may be used for a variety of purposes including the transportation of passengers and cargo.

Background

While this approach reduces the weight of the motor and aircraft drag, the articulated motor and propeller result in increased design complexity such that six to twelve tiltrotors are required to provide the necessary lift and thrust.

Disclosure of Invention

In various embodiments, the above-described and other problems are solved by a VTO L aircraft that transitions from a VTOL state, where stacked propellers are used primarily to generate lift, to cruise, where one or more wings are used primarily to generate lift.

During vertical ascent of the aircraft, the rotating wing tip propellers on the pod are tilted upwards at a 90 degree angle and the stacked lift propellers are deployed from the wing and tail boom to provide lift. The hinged control surfaces are inclined to control rotation about a vertical axis during takeoff. When the aircraft transitions to the cruise configuration, the nacelle rotates down to a zero degree position, allowing the wing tip propeller to provide forward thrust. The control surface returns to a neutral position in which the wing, tail boom and tail and stacked lift propellers stop rotating and are retracted into cavities in the wing boom and tail boom to reduce drag during forward flight.

During the transition to the descent configuration, the stacked propellers are re-deployed from the wing and tail booms and begin to rotate along the wing and tail to generate the lift required for descent. The nacelle rotates back up to the 90 degree position and provides both thrust and lift during the transition. The hinged control surfaces on the wing are tilted down to avoid the propeller wake, while the hinged surfaces on the tail boom and tail are tilted for yaw control.

Drawings

Fig. 1 illustrates an M-wing configuration of a VTO L aircraft according to one or more embodiments.

Fig. 2A is a side view of a stacked propeller according to one or more embodiments.

Fig. 2B is a top view of a stacked propeller according to one or more embodiments.

Figure 3 illustrates various configurations of stacked propellers according to several embodiments.

Fig. 4A illustrates a configuration of a stacked propeller during a first mode of operation according to one or more embodiments.

Fig. 4B illustrates a configuration of a stacked propeller during a second mode of operation according to one or more embodiments.

Fig. 4C illustrates a configuration of a stacked propeller during a third mode of operation according to one or more embodiments.

Fig. 4D illustrates a configuration of a stacked propeller during a fourth mode of operation according to one or more embodiments.

Fig. 4E illustrates a side view of an aircraft having a boom control actuator in accordance with one or more embodiments.

Fig. 5 illustrates a climb configuration of the VTO L aircraft according to the embodiment of fig. 1.

Fig. 6 illustrates an early departure transition configuration of the VTO L aircraft according to the embodiment of fig. 1.

Fig. 7A illustrates a late transition-out configuration of the VTO L aircraft according to the embodiment of fig. 1.

Fig. 7B illustrates a top view of a propeller configuration associated with one or more operating modes according to the embodiment of fig. 7A.

Fig. 7C illustrates a top view of a propeller configuration associated with one or more operating modes according to the embodiment of fig. 7A.

Fig. 8 illustrates a cruise configuration of the VTO L aircraft according to the embodiment of fig. 1.

Fig. 9 illustrates an early approach transition configuration of a VTO L aircraft according to the embodiment of fig. 1.

Fig. 10 illustrates a late approach transition configuration of the VTO L aircraft according to the embodiment of fig. 1.

Fig. 11 illustrates a descent configuration of the VTO L aircraft according to the embodiment of fig. 1.

Detailed Description

The figures and the following description depict certain embodiments by way of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein. Reference will now be made to several embodiments, examples of which are illustrated in the accompanying drawings. Note that where feasible, similar or identical reference numbers may be used in the figures and may indicate similar or identical functions.

1.1 aircraft overview

FIG. 1 is an illustration of a vertical take-off and landing (VTO L) aerial vehicle 100, the illustrated VTO L aerial vehicle 100 is a transitional aerial vehicle that transitions from a vertical take-off state, in which lift is generated using propellers, to a cruise state, in which lift is generated using wings, the aerial vehicle 100 is used to transport passengers and cargo, the aerial vehicle 100 is configured to move relative to three axes in FIG. 1, the roll axis is collinear with the x-axis, the pitch axis is collinear with the y-axis, the yaw axis is collinear with the z-axis, i.e., perpendicular to the x-axis and the y-axis (e.g., the z-axis extends from the page), the origin of the coordinate system is fixed at the center of gravity of the aerial vehicle 100 during one or more modes of operation.

Aircraft 100 includes an aerodynamic center and a thrust center. The aerodynamic center is the point of the aircraft at which the aerodynamic moment is constant. The aerodynamic moment results from the forces exerted on the aircraft 100 by the surrounding gas (e.g., air). The thrust center is a point along the aircraft 100 at which thrust is applied. The aircraft 100 includes components that are strategically designed and positioned so that the aerodynamic center, thrust center, and/or center of gravity may be approximately aligned (e.g., separated by a distance of no more than five feet (1.524 meters)) during various modes of operation. The components of aircraft 100 are arranged such that aircraft 100 is balanced during vertical and forward flight. For example, components such as control surfaces (e.g., tail control surfaces, boom control actuators), propellers, and M-wing shapes work in concert to balance the aircraft 100 during different operating modes.

The aircraft 100 includes an M-shaped wing configured to the body of the fuselage 135 and a tail region extending from the rear of the fuselage 135. In the embodiment of fig. 1, aircraft 100 includes a port side portion and a starboard side portion. The wings are arranged in an M-shaped configuration such that the port and starboard portions of the wings each have two angled sections that merge at an inflection point. The first section extends outwardly from the fuselage 135 to an inflection point, while the second section extends outwardly from the inflection point. The first section and the second section are connected at a non-zero angle at the inflection point. In various embodiments, the angle is in a range from 5 degrees to 25 degrees. In other embodiments, other angles may be used.

The leading edge (e.g., inflection point) where the angled sections merge is the forwardmost point along each portion of the M-shaped airfoil. The leading edge is the portion of the wing that is first in contact with the air during forward flight. In one embodiment, the inflection point where the angled members merge coincides with the midpoint of each portion of the wing (e.g., port portion, starboard portion). In one embodiment, the port and starboard portions of the wing may be separate members, each having a wide V-shape. In the embodiment of fig. 1, the wing is a continuous M-shaped configuration, but in an alternative embodiment the wing includes two separate V-shaped wings (e.g., starboard, port) attached to the fuselage 135.

The shape of the M-shaped airfoil is selected to reduce the surface area that generates drag during takeoff and landing configurations, while providing sufficient lift during forward flight. In one embodiment, the span is approximately 30 to 40 feet, and the distance from the tip end of the starboard cruise propeller 110 to the port cruise propeller 110 (described in more detail below) is approximately 40 to 50 feet. The wing surface area is about 110 square feet to 120 square feet. Alternatively, the wings may be of any suitable size for providing lift to the aircraft.

In one embodiment, the M-shaped wing includes wing booms 120, wherein the leading edge of each wing boom 120 is located at an approximate midpoint of each portion of the wing (e.g., the inflection point where the angled sections of each portion of the wing merge). The wing boom 120 may be attached to the wing at the leading edge and may protrude from the leading edge by 1 foot to 3 feet. In one embodiment, the center of mass of the wing boom 120 is on or before the neutral axis of the wing. The wing booms 120 may include additional elements, such as batteries, to align and/or balance the center of gravity of the aircraft 100 during the operational mode.

In one embodiment, stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b) may be attached to the wing booms 120. Stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b) may be positioned behind the wings to provide lift and stability to the aircraft 100. Positioning the stacked propellers behind the wing allows for improved circulation over the wing and the stacked propellers. Thus, during vertical take-off and landing, the stacked propellers can make a significant contribution to lift. The position of the stacked propellers also allows the aerodynamic center, thrust center and center of gravity of the aircraft to be aligned in different modes of operation.

The aircraft 100 includes an aft region attached to an aft end of the fuselage 135. The tail region may include a tail boom 145 and a tail. In one embodiment, the aircraft includes a T-shaped tail configured to provide stability to the aircraft 100. The T-shaped tail is shaped and positioned to provide lift to the aircraft during normal operation. Thus, the T-shaped tail may be referred to as a lift tail. The T-shaped tail includes a tailplane 155 mounted perpendicular to the top of the straight tail 448. A straight tail wing 448 is shown in the profile view of the aircraft 100 in fig. 4E, and may include a rudder 457 that rotates to control the yaw motion of the aircraft 100. The tailplane 155, which is attached to the top of the straight tail 448, may include one or more tail control surfaces 160 located at the rear of the tailplane 155. In one embodiment, the T-shaped tail is configured to position the aerodynamic center above a designated passenger seat (e.g., a rear passenger seat) such that the aerodynamic center coincides (or nearly coincides) with the center of gravity during vertical flight. The T-shaped tail may also facilitate adjusting the aerodynamic center toward the nose of the fuselage 135 (e.g., slightly forward of the wing) during cruise configurations.

The T-shaped tail is about 4 feet to 6 feet high from the base of the straight tail 448 to the top of the tailplane 155, and the tailplane 155 is about 10 feet to 20 feet wide. The T-shaped tail may be sufficiently high such that the angle of the tail control surface 160 may change when one or more propellers attached to the tail boom cause a negative airflow angle of attack during a transition configuration, such as an approach (range) and an approach (ingress) described in more detail below. Changing the tail control surface may reduce any negative impact of the airflow generated by the propeller on the T-shaped tail during the transition. In one embodiment, a position light is positioned on the rear of the tail to alert other aircraft of the position and heading of the aircraft 100. Propellers (e.g., front stacked propellers 140a, rear stacked propellers 140b) may be attached to the aft boom 145. Alternatively, one or more propellers may be located at any point along the aft region. Similar to stacked wing propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b), the tail propeller may be strategically positioned along the tail to facilitate alignment of the aerodynamic center, thrust center, and center of gravity.

The aircraft 100 relies on propellers for vertical takeoff and landing as described below with respect to fig. 5 and 11. The aircraft 100 includes stacked propellers (starboard stacked propeller 115a, port stacked propeller 115b, forward stacked propeller 140a, aft stacked propeller 140b) and single-rotor propellers (cruise propellers 110) to maximize lift. The propellers may be oriented along the span of the aircraft 100 (e.g., laterally) to prevent disturbance of the propeller flow during the transition and to minimize the power required to transition from the vertical configuration to the cruise configuration. The position of the propellers may prevent turbulent wakes (e.g., turbulent airflow generated by the propellers) from entering between the propellers. The propellers may be positioned so that the airflow of one propeller does not negatively interfere with the airflow of the other propeller. The arrangement of the propeller may also allow for a more elliptical lift and downwash airflow distribution during the transition configuration to achieve lower induced drag, power and noise. In one embodiment, the aircraft 100 has a propeller area of about 331 square feet, such that an aircraft 100 with a mass of about 4500 pounds has a disk load of about 13.6 pounds per square foot. The disk load is the average pressure change across the actuator disk, more specifically across the rotor or propeller. In other embodiments where the propeller area is about 391 square feet (e.g., where the diameter of the cruise propeller 110 and the stacked wing propellers is about 10 feet), the disk load will be reduced to 11.5. When the disk load is reduced, the power usage can be reduced, and thus the efficiency of the aircraft can be improved by reducing the disk load. The combination and configuration of the propellers of the aircraft 100 generate a disk load that allows the aircraft 100 to generate sufficient lift to transport large loads using a reasonable amount of power without generating excessive noise.

1.2 aircraft fuselage

As shown in FIG. 1, the fuselage 135 is located at the center of the span and includes a passenger compartment configured to accommodate passengers, cargo, and/or pilots. The fuselage 135 is approximately 35 feet to 45 feet long, approximately 4 feet to 8 feet wide, and approximately 5 feet to 12 feet tall. In alternative embodiments, the fuselage 135 may have any suitable dimensions for transporting passengers and/or cargo.

The passenger compartment may include one or more passenger seats. In one embodiment, the passenger compartment includes seats that can accommodate up to four passengers. The seats may be arranged in two parallel rows, two seats in each row, such that one row of passengers faces the aft portion of the aircraft 100 while the other row of passengers faces the nose portion of the aircraft 100 (e.g., the forward region of the fuselage 135). In one embodiment, the passenger seats may be arranged in tiers such that one row of seats is elevated above the other to maximize space and provide a place for passengers to rest their feet. Alternatively, the seats may be arranged in a single row having two groups of two seats, each seat in a group facing in opposite directions, such that the passengers in the first and third seats face the aft portion of the aircraft 100, and the passengers in the second and fourth seats face the nose portion of the aircraft 100. In other configurations, all four seats face the nose or tail of the aircraft 100. The arrangement of the passenger seats may have alternative configurations in order to distribute the weight of the passengers in a particular manner in order to balance the aircraft 100 in the operational mode. In other embodiments, the fuselage 135 may include a greater or lesser number of seats.

The fuselage 135 may also include a viewing screen in the passenger compartment for providing information about the flight. For example, the viewing screen may contain information such as estimated arrival times, altitudes, speeds, information about the originating and destination locations, and/or communications from the pilot. The forward region of the fuselage 135 (e.g., the region closest to the nose of the aircraft 100) includes a cockpit having a control panel and a pilot seat. In one embodiment, the front of the cockpit is located in front of the horizontal plane of the cruise propeller 110 so that the blades of the cruise propeller 110 are not in line with the pilot.

In some embodiments, a battery pack is positioned below the passenger compartment in the fuselage 135. The battery pack is spaced apart from the bottom surface of the body 135 to facilitate ventilation of the battery pack. The bottom surface of the body 135 may also include a battery door to allow removal of the battery pack. In an alternative embodiment, the battery may be placed above the fuselage 135 and integral with the wing. Fuselage 135 may include a charging port on the nose where aircraft 100 may be attached to a charging station to recover electrical energy stored in batteries that power aircraft 100. Fixed or retractable landing gear may also be attached to the bottom of fuselage 135 to facilitate landing of aircraft 100 and to allow short-range movement of aircraft 100 over the ground. Alternatively, the aircraft 100 may have landing skids protruding from the bottom of the fuselage 135 and include attachment points for the wheels.

1.3 control surface

In the embodiment of fig. 1, the aircraft 100 includes a wing control surface 130 that spans the trailing edge of the wing. The trailing edge is the edge opposite the leading edge of the wing. In one embodiment, each wing section has three wing control surfaces 130 along the rear of the wing: a first wing control surface approximately 5 feet to 7 feet long between the fuselage 135 and the wing boom 120, and a second wing control surface and a third wing control surface each approximately 3 feet to 5 feet long between the wing boom 120 and the wing pod 112. The wing control surfaces 130 may be deployed at different angles during operation of the aircraft to increase the lift generated by the wings and control the pitch of the aircraft 100. The wing control surfaces 130 are hinged such that they can rotate about hinge axes parallel to the wings. For example, the wing control surfaces 130 are in a neutral position during the parked configuration and are rotated approximately 40 degrees below a plane parallel to the x-y plane to facilitate takeoff. The mode of operation of the wing control surface 130 is described in more detail below in connection with fig. 5-11.

Aircraft 100 may also include control surfaces at other locations along the aircraft, such as tail control surface 160 (as described above) and rudder 457 (shown in fig. 4E). Control surfaces on the tail (e.g., tail control surface 160, rudder 457) may adjust the aerodynamic center of aircraft 100 to dynamically stabilize aircraft 100 in different operating modes. For example, during cruise configuration, trailing control surface 160 is neutral (i.e., tilted to a zero degree angle), while trailing control surface 160 is tilted about 5 to 10 degrees during descent. During the transition to the cruise configuration, the rudder 457 is neutral (i.e., tilted to a zero degree angle), and during descent, the rudder 457 is tilted approximately 5 to 10 degrees to yaw the aircraft 100 into a correct landing orientation. The rudder 457 may be operated in addition to or in place of a boom control actuator as described below to perform yaw control. The mode of operation of the aft control surface 160 and the rudder 457 is described in more detail below in connection with fig. 5-11.

In some configurations, the aircraft 100 may include control surfaces on the bottom of each of the wing booms 120 and tail booms 145, each control surface being inclined to yaw the aircraft 100. The control surface may deflect the propeller flow to generate control forces, resulting in yaw and direct side-slip capabilities. For example, while the control surfaces are neutral (i.e., at zero degrees) during the cruise configuration, they rotate slightly (e.g., about five to ten degrees) during descent to yaw the aircraft 100 into the correct orientation. In one embodiment, the control surface on the bottom of each of the wing boom 120 and the tail boom 145 is a boom control actuator, which will be described in more detail below.

1.4 cruise propeller

In one embodiment, the aircraft 100 includes one or more cruise propellers 110 shown in FIG. 1. The cruise propellers 110 provide lift to the aircraft 100 during takeoff and landing, and provide forward thrust to the aircraft 100 during a cruise configuration. As shown in fig. 1, the cruise propeller 110 is mounted on the nacelle 112 perpendicular to the fuselage 135. In one embodiment, pods 112 have a non-circular cross-section to reduce the effect of aerodynamic forces on aircraft 100. Each pod 112 rotates about an axis parallel to the y-axis during different modes of operation. As discussed in more detail below in connection with fig. 5-11, during vertical takeoff and landing, the nacelle 112 is perpendicular to the fuselage 135 such that the blades of the cruise propeller 110 rotate in a plane parallel to the x-y plane to facilitate vertical movement of the aircraft 100. When the aircraft 100 enters an off-ground configuration (i.e., when the aircraft 100 approaches cruise altitude), the nacelle 112 and cruise propeller 110 rotate downward (e.g., toward the nose of the fuselage 135 about an axis parallel to the y-axis) until the nacelle is parallel with the fuselage 135 to facilitate forward propulsion of the aircraft 100. When the aircraft 100 enters an approach configuration (i.e., when the aircraft 100 begins to descend), the nacelle 112 and the cruise propeller 110 rotate upward (toward the positive z-direction about an axis parallel to the y-axis) until the blades of the cruise propeller 110 remain horizontal in a plane parallel to the x-y plane, where they remain during descent and landing of the aircraft 100. In one embodiment, the cruise propeller 110 may be counter-rotating. For example, during one mode of operation, the port cruise propeller 110 rotates in a clockwise direction, while the starboard cruise propeller 110 rotates in a counterclockwise direction.

In one embodiment, each of the cruise propellers 110 has five blades, but they may have fewer or more blades in other embodiments. The blades of the cruise propeller 110 narrow from the root to the tip of the blades. The cruise propeller 110 may have a fixed pitch (e.g., the cruise propeller 110 is held at a fixed angle of attack). Alternatively, the pitch is variable such that the blades of the cruise propeller 110 may be partially rotated to control the blade pitch. The cruise propeller 110 may be driven by a separate electric motor. Each cruise propeller 110 is approximately 8-10 feet in diameter and is attached at a 90 degree angle to a nacelle 112 (e.g., nacelle 112 is parallel to the z-axis) at the free end of each portion of the wing (e.g., starboard portion, port portion). Alternatively, the cruise propeller 110 may have any suitable dimensions.

1.5 stacked propeller

The aircraft may include one or more stacked propellers. The propellers may be located in the forward, aft, port and/or starboard regions of the aircraft. In the embodiment of fig. 1, aircraft 100 includes starboard stacked propellers 115a and port stacked propellers 115b, where starboard stacked propellers 115a and port stacked propellers 115b may be attached to a wing or wing boom 120 of the aircraft. The embodiment of fig. 1 also includes stacked tail propellers (e.g., front stacked propellers 140a, rear stacked propellers 140b) that may be attached to the tail boom 145. Alternatively, the stacked propellers may be located at any other location on the aircraft 100.

The stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b, forward stacked propeller 140a, aft stacked propeller 140b) are used to provide lift and thrust to the aircraft during takeoff and landing. Fig. 2A and 2B illustrate side and top views of a stacked propeller according to an embodiment. The stacked propellers include a first propeller 260 and a second propeller 262. The first and second propellers 260, 262 each include two blades 269 coupled to a blade hub 268. The blades 269 of the first propeller 260 and the blades 269 of the second propeller 262 rotate together about the axis of rotation 264. The first propeller 260 and the second propeller 262 may have variable pitch.

The first propeller 260 may be coupled (e.g., mechanically coupled, electrically coupled) to a first motor 280, and the second propeller 262 may be coupled to a second motor 282 to enable independent control of each propeller. In some embodiments, the first motor 280 or the second motor 282 may control both the first propeller 260 and the second propeller 262. For example, if the first motor 280 fails (e.g., the battery is dead), the second motor 282 may control the rotation of the first and second propellers 260, 262. The stacked propellers may also include a clutch that allows the first and second propellers 260, 262 to be locked together to ensure a proper azimuth angle 266 during the operating mode. The clutch allows the stacked propellers to provide thrust from both the first propeller 260 and the second propeller 262, even in cases where one of the motors (e.g., the first motor 280) fails while the other motor (e.g., the second motor 282) controls the rotation of the first propeller 260 and the second propeller 262. In some embodiments, the stacked propeller may include a single motor and a controller with a clutch for controlling the azimuth angle 266 used in the operating mode, while in other embodiments, the stacked propeller may include two motors with independent controllers and a clutch used in the event of failure of one of the motors. The first and second motors 280, 282 may also control the precise azimuth angle 266 of the first propeller 260 relative to the second propeller 262 shown in fig. 2B when the blades are stationary or moving. The azimuth angle 266 depends on the operating mode of the aircraft, which will be described in more detail below.

The co-rotating propellers (e.g., first propeller 260, second propeller 262) may be synchronized such that they rotate at the same speed to reduce noise generated by the aircraft 100. The azimuth angle 266 is constant when the first propeller 260 and the second propeller 262 are rotating at the same speed (e.g., during steady flight). The azimuth angle 266 may depend on the shape and/or mode of operation of the blade 269. For example, a particular shape, such as the shape shown in fig. 2B, may have an offset angle of 5 to 15 degrees during different modes of operation.

The speed of the propeller may be adjusted based on the amount of thrust required to provide vertical ascent and descent and the amount of noise allowed in the geographic area in which the aircraft 100 is traveling. For example, in areas where a lower noise level is desired (e.g., residential areas), the pilot may reduce the speed of the aircraft 100, thereby causing the aircraft 100 to climb more slowly. In one embodiment, the maximum speed of the free end of each of the blades 269 is 450 feet per second. This may keep the noise generated by the aircraft 100 below an acceptable threshold. In other embodiments, other maximum speeds may be acceptable (e.g., depending on the level of noise deemed acceptable for the aircraft and/or aircraft environment, depending on the shape and size of the blades 269, etc.).

In one embodiment, the stacked propeller may be enclosed in a duct 265. A conduit 265 may surround the blades 269 and the rotor shaft 270 to enhance flow over the first and/or second propellers 260, 262. The duct 265 may serve to increase the thrust produced by the stacked propellers and/or adjust the pressure differential above and below the co-rotating propellers. The first propeller 260 and the second propeller 262 may be recessed into the duct 265, as shown in fig. 2A. In alternative embodiments, the first propeller 260 may protrude from the duct 265 or be flush with the duct 265, while the second propeller 262 may be recessed within the duct 265. Similarly, mast 270 may be recessed within conduit 265 or protrude from conduit 265. In the embodiment of fig. 2A, the conduit 265 is a cylinder having a diameter slightly larger than the diameter of the first and second propellers 260, 262.

Co-rotating propellers may provide advantages over single rotor propellers in that co-rotating propellers may produce less noise. The noise generated by the propeller varies exponentially with the tip speed of the propeller, and therefore, to reduce the noise generated by the single-rotor propeller, the aircraft speed is also reduced. The stacked propeller design also allows for angular flexibility between the propellers, which can vary during different phases of flight, serving to increase system efficiency. The speed and phase angle can be adjusted for each propeller on a stacked propeller, thereby achieving a more flexible, adaptive system. The stacked propellers may be stowed during modes of operation where they are not required to reduce drag and improve efficiency.

The configuration of the stacked propellers may vary depending on the implementation and requirements and/or the mode of operation of the aircraft system. In one embodiment, each of the co-rotating propellers (e.g., first propeller 260, second propeller 262) has the same blade shape and profile, while in other embodiments, the first propeller 260 and the second propeller 262 have different sizes and rotational offset phases. For example, the first and second propellers 260, 262 may have different camber and twist such that the stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b, front stacked propeller 140a, rear stacked propeller 140b) are able to achieve optimal camber between the two surfaces when the propellers are azimuthally separated. For example, in one embodiment, the diameter of the second propeller 262 is about 95% of the diameter of the first propeller 260.

With respect to material composition, the stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b, forward stacked propeller 140a, aft stacked propeller 140b) may be made of a single material or may be a composite material capable of providing suitable physical properties to provide lift to the aircraft. The first propeller 260 and the second propeller 262 may be made of the same material or different materials. For example, the first and second propellers 260, 262 may be made of aluminum, or the first propeller 260 may be made of steel and the second propeller 262 may be made of titanium. The blade hub 268 may be made of the same or different material as the first and second propellers 260, 262. Alternatively, the components of the system (e.g., the first propeller 260, the second propeller 262, the blade hub 268) may be made of metal, polymer, composite material, or any combination of materials. The stacked propellers may also be exposed to extreme environmental conditions such as wind, rain, hail, and/or extreme high or low temperatures. Thus, the material of the stacked propeller can be adapted to various external conditions.

With respect to mechanical properties, the material of the first and second propellers 260, 262 may have compressive strength, shear strength, tensile strength, bending strength, modulus of elasticity, stiffness, derivatives of the above mechanical properties, and/or other properties that enable the propellers to provide vertical lift to the aircraft. The first and second propellers 260, 262 may be subjected to extreme forces during operation including thrust bending, centrifugal and aerodynamic twisting, torque bending and vibration. The material of the first propeller 260 and the second propeller 262 may have a strength and stiffness that allows the propellers to maintain their shape under forces exerted on the propellers during various modes of operation. In one embodiment, the first propeller 260 and/or the second propeller 262 are constructed of a rigid composite material. In addition, the edge or tip of the blade 269 may be lined with metal for added strength and rigidity.

In one embodiment or during certain modes of operation, the first propeller 260 and the second propeller 262 may rotate together in a counterclockwise direction. In different modes of operation, the first propeller 260 and the second propeller 262 may rotate together in a clockwise direction. In the embodiment of fig. 1, stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b) along the aircraft may rotate in opposite directions based on the mode of operation. For example, the starboard stacked propeller 115a may rotate in a clockwise direction, and the port stacked propeller 115b may rotate in a counterclockwise direction. The stacked propellers (e.g., front stacked propeller 140a, rear stacked propeller 140b) may also rotate in the same or opposite directions. For example, during one mode of operation, the front and rear stacked propellers 140a, 140b may both rotate in a clockwise direction. The direction of rotation of the stacked propellers may depend on the mode of operation. According to the embodiment in fig. 1, the stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b, front stacked propeller 140a, rear stacked propeller 140b) have a diameter of about 6 to 10 feet. Alternatively, the stacked propellers may have any suitable dimensions. Stacked tail propellers (e.g., forward stacked propeller 140a, aft stacked propeller 140b) may operate in addition to or in place of starboard stacked propeller 115a and port stacked propeller 115 b. The above description does not exclude possible combinations of the rotation directions of each stacked propeller. The examples are for illustrative purposes.

Fig. 3 illustrates a first embodiment (upper left), a second embodiment (upper right), a third embodiment (lower left) and a fourth embodiment (lower right) of a stacked propeller. The first embodiment (top left) shows a top view of a stacked propeller including a first propeller 360a and a second propeller 362a having angled blades 369 a. The first propeller 360a and the second propeller 362a each include two blades 369 a. The width of the blades 369a is narrower at the blade hub 368a than at the free ends of the blades 369 a. The second embodiment of fig. 3 (top right) includes a first propeller 360b having three blades 369b and a second propeller 362b having three blades 369 b. The vanes 369b are wider at the vane hub 368b than at the free ends of the vanes 369 b. The free ends of the vanes 369b are rounded. The third embodiment of fig. 3 (bottom left) shows a schematic view including a first propeller 360b and a second propeller 362b, each of the first and second propellers 360b, 362b including two blades 369b coupled to a blade hub 368 c. The blades 369b of the propeller are wider at the blade hub 368c than at the free end. The diameter of the second propeller 362c is smaller than the diameter of the first propeller 360 c. The fourth embodiment of fig. 3 (lower right) includes a propeller having a first propeller 360d and a second propeller 362d, each of the first propeller 360d and the second propeller 362d including two blades 369d coupled to a blade hub 368 d. The blades 369d are curved along a length from the blade hub 368d to the free ends of the blades 369 d.

Fig. 3 shows several embodiments and combinations of embodiments of stacked propellers. Alternatively, the stacked propellers may have different characteristics (e.g., shape, orientation, size) and different combinations of embodiments to meet design constraints (e.g., load capacity, manufacturing limitations) of the aircraft. The stacked propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b, forward stacked propeller 140a, aft stacked propeller 140b) may also have a different number of propellers, each propeller having a different number of blades to improve aircraft efficiency or reduce noise. In one embodiment, the stacked propeller includes different blade pitches and different twist profile on each set of blades. The first propeller (e.g., the top propeller) may have a lower pitch to induce airflow, while the second propeller (e.g., the propeller below the top propeller) may have a higher pitch to accelerate airflow. The twist profile may be configured to stabilize the interaction of tip vortices (e.g., vortices generated by the tip velocity of the upper blade) with the lower blade in order to generate optimal thrust.

Fig. 4A shows a side view of one embodiment of a stacked propeller in one mode of operation, while fig. 4B shows a side view of an embodiment of a stacked propeller in a different mode of operation. The stacked propeller shown in fig. 4A-4D is substantially similar to the stacked propeller shown in fig. 2A-2B. The schematic includes first propeller 460, second propeller 462, blade hub 468, blades 469, rotor shaft 470, and internal cavity 472. Fig. 4A shows a schematic view in which first propeller 460 and second propeller 462 are coupled to mast 470. Mast 470 includes an internal cavity 472. In one embodiment, rotor mast 470 is a boom (e.g., wing boom 120, tail boom 145). In an alternative embodiment, rotor mast 470 may be a pod (e.g., pod 112). The boom and/or the pod may be configured to have a surface profile that matches the blade profile of the first propeller 460. This achieves a conformal surface fit between first propeller 260 and mast 470 to minimize drag and flow separation. In one mode of operation shown in fig. 4B, blades 469 of first and second propellers 460, 462 may be recessed within interior cavity 472 of mast 470 to reduce drag. The first propeller 460 and/or the second propeller 462 may be simultaneously recessed to cooperate with an operational mode, which will be described in more detail below in connection with fig. 5-11.

1.6 boom control actuator

The aircraft may include a boom attached to a region of the aircraft. In one embodiment, such as illustrated in fig. 1, a boom is attached to each wing of the aircraft 100 and/or to the tail of the aircraft 100. Typically, the boom contains auxiliary items, such as a fuel tank. These articles may also be used to provide structural support for the aircraft. In one embodiment, the boom may include boom control actuators that facilitate different modes of operation of the aircraft.

In the embodiment of fig. 1, propellers (e.g., starboard stacked propellers 115a, front stacked propellers 140a) may be coupled to booms (e.g., wing booms 120, tail booms 145) to provide lift to the aircraft during takeoff and landing of the aircraft. As shown in fig. 1, a starboard stacked propeller 115a is attached to the starboard side wing boom 120 and a port stacked propeller 115b is attached to the port side wing boom 120. Attached to the aft boom 145 are a front stacked propeller 140a and a rear stacked propeller 140 b. In an alternative embodiment, a single-rotor propeller (e.g., cruise propeller 110) may be attached to the boom.

The booms (e.g., wing booms 120, tail booms 145) may be hollow and may be used to store aircraft components useful for operation. For example, the boom may include an electric motor and a battery to power propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b) or other aircraft components. In one embodiment, the battery is located at the bottom of the wing boom 120 and may span the length of the boom 120. In other embodiments, a battery may be located at either end of the wing boom 120 or the tail boom 145 to act as a counterweight to help maintain balance and alignment of the aircraft 100. Batteries may also be placed in position in the wing boom 120 or the tail boom 145 to minimize aeroelastic and rotational flutter resonances during the operating mode. The battery may also be included at another location along the aircraft 100. A battery door may be positioned on the bottom of the wing booms 120 to allow for removal of the battery that powers the propeller (e.g., starboard stacked propeller 115a, port stacked propeller 115b) or another aircraft component.

In embodiments where the wing boom 120 and/or the tail boom 145 are hollow, the boom may act as a resonator to alter the noise signature of the aircraft 100 during one or more modes of operation. A helmholtz resonator (helmholtz resonator) is a container of a gas, such as air, with openings. The resonator may be tuned to the frequency of the propeller such that noise generated by airflow over the propeller coupled to the boom (e.g., wing boom 120, tail boom 145) is reduced. The sound produced by the pressure fluctuations produced by the propeller may be modified by the presence of an adjusted volume inside the boom. Adjusting the volume may allow for acoustic and aerodynamic modifications such that radiated sound emitted by a propeller coupled to the boom is reduced. In one embodiment, the booms (wing boom 120, tail boom 145) have an appropriate air volume relative to the size of the propeller to act as a resonator. In one mode of operation, when the stacked propeller is deployed (e.g., take off), as described below in connection with fig. 4A, the internal cavity 472 may serve as an inlet for airflow into the resonator. A portion of the airflow over the stacked propellers may flow into the booms (e.g., wing booms 120, tail boom 145) via the internal cavity 472 and the frequency may be adjusted to reduce the noise generated by the propellers. In one embodiment, the boom control actuator 425 may operate in cooperation with a boom (e.g., wing boom 120, tail boom 145) operating as a resonator to reduce noise. As described in more detail below, the rotational frequency of the boom control actuator may be configured to coordinate with the frequency of the resonator in order to further mitigate noise.

When the aircraft 100 is in a vertical takeoff and landing configuration, propellers (e.g., starboard stacked propeller 115a, port stacked propeller 115b) blow air through the wing booms 120 and the tail boom 145 to generate lift. Fig. 4A-4D illustrate cross-sectional views of embodiments of booms (e.g., tail boom 145, wing boom 120). Fig. 4A-4D illustrate the flow of air over the boom during different modes of operation. The boom may include a boom control actuator 425, the boom control actuator 425 configured to rotate about an axis perpendicular to the rotation axis 464. The boom control actuator may be a single actuator or a split actuator as described by fig. 4A-4D. The split actuator may operate in cooperation with a boom operating as a resonator to reduce noise generated by the propeller. The split actuator may include two boom control actuators attached to a single rotor mast 470.

In one embodiment, the boom may include a mast 470 coupled to boom control actuator 425. Boom control actuator 425 may be configured to direct airflow from the propeller. Fig. 4A illustrates the boom control actuator 425 during an operating mode, such as a vertical takeoff configuration, as described in more detail below. Boom control actuator 425 is in a neutral position in fig. 4A. The airflow 490 below the propellers (e.g., first propeller 460, second propeller 462) is not separated from the surface of the boom. Fig. 4B illustrates an operating mode, such as a cruise configuration, in which the propellers (e.g., first propeller 460, second propeller 462) are recessed within the internal cavity 472. When the propellers (e.g., first propeller 460, second propeller 462) are recessed within the cavity 472, the boom control actuator 425 may not be operational (e.g., the boom control actuator remains in a neutral position).

Fig. 4C-4D illustrate two other modes of operation of the boom control actuator according to one embodiment. Fig. 4C-4D illustrate the boom control actuator 425 rotating about an axis perpendicular to the rotation axis 464 (e.g., an axis extending out of the page). During various modes of operation, the angle of boom control actuator 425 directs downstream airflow 490 in a direction that is offset from an axis parallel to the z-axis of the boom (i.e., offset left or right), as described in more detail below in connection with fig. 5-11. The angle of boom control actuator 425 may be controlled manually or automatically during different modes of operation. The angle may remain constant during one mode of operation or may change based on environmental conditions. Alternatively, boom control actuator 425 may be configured to oscillate continuously about an axis perpendicular to rotational axis 464. As described above, the oscillation frequency can be adjusted to match the frequency of the boom functioning as a resonator. In an alternative embodiment, boom control actuator 425 may be configured to direct airflow 490 in another direction. The movement of the boom control actuator 425 is configured to control the cross wind of the propeller and mitigate the acoustic characteristics of the propeller. The boom control actuator 425 may control the direction of the airflow 490, which may result in a significant reduction in the noise generated by the propeller. Boom control actuators 425 may also allow for enhanced yaw control of the aircraft. Boom control actuators 425 may also improve efficiency and reduce power consumed by aircraft 100 by realigning airflow.

In fig. 4A-4D, boom control actuator 425 has a teardrop shape. In other embodiments, boom control actuator 425 may have another shape suitable for reducing noise and directing airflow. For example, boom control actuator 425 may have a split configuration such that during one mode of operation, boom control actuator 425 has multiple longitudinal surfaces configured to control the direction of airflow. The split configuration can be configured to allow the boom to act as a resonator, as described above. In one embodiment, the boom control actuators 425 and corresponding booms (e.g., tail boom 145, wing boom 120) have non-circular cross-sections to reduce undesirable effects of aerodynamic forces on the aircraft 100 (e.g., aeroelasticity and rotational flutter). Boom control actuator 425 may also have a rectangular end region coupled to rotor mast 470 and a pointed or rounded free end region. The shape of the boom control actuator 425 depends on design considerations of the aircraft (e.g., the size of the propeller, the position of the propeller, the aircraft load capacity, etc.).

A side view of the aircraft 100 including the wing boom and the tail boom is shown in fig. 4E. The side view illustrates a boom control actuator 425 coupled to a portion of the wing boom 420. The boom control actuator 425 extends along a longitudinal surface of the wing boom 420 and is located below the propeller. In one embodiment, the diameter of the propeller is approximately equal to the length of the boom control actuator 425. In alternative embodiments, the diameter of the propeller may be greater or less than the length of the boom control actuator 425. The internal cavity 472 described above may have a length similar to the length of the boom control actuator 425. Also shown in fig. 4E is an aircraft tail boom 445 according to one embodiment. The aircraft tail boom 445 includes a boom control actuator 425 that spans the length of the tail boom. Two sets of propellers are coupled to the tail boom 445. The length of the tail boom control actuator 425 is approximately equal to the combined diameter of the tail propellers (e.g., front stacked propellers 140a, rear stacked propellers 140 b). In alternative embodiments, the length of the boom control actuator 425 may be less than or greater than the overall diameter of the propeller. The internal cavity 472 described above may have a length similar to the length of the tail boom control actuator 425.

With respect to material composition, the boom control actuator 425 may be made of a single material or may be a composite material capable of providing suitable physical properties to control the direction of airflow behind the propeller. Boom control actuator 425 may be made of the same material as rotor mast 470 or a different material. Boom control actuator 425 may also be exposed to extreme environmental conditions, such as wind, rain, hail, and/or extreme high or low temperatures. Thus, the material of the boom control actuator 425 may be compatible with a variety of external conditions.

With respect to mechanical properties, the material of the boom control actuator 425 may have compressive strength, shear strength, tensile strength, bending strength, modulus of elasticity, hardness, derivatives of the above mechanical properties, and/or other properties that enable the boom control actuator 425 to direct the airflow 490 behind or below the propeller. Boom control actuator 425 may be subjected to extreme forces during operations including thrust bending, centrifugal and aerodynamic twisting, torque bending, and vibration. The material of boom control actuator 425 may have a strength that allows boom control actuator 425 to maintain its shape under forces exerted on boom control actuator 425 during various operating modes.

As described above, boom control actuators (e.g., 425) may be included in VTO L aircraft 100. boom control actuators 425 may be configured to direct airflow behind or below a propeller included in aircraft 100.

1.7 modes of operation

The aircraft mission profile 000 shown in FIGS. 5-11 illustrates the approximate trajectory of the VTO L aircraft 100 from stage 001 to stage 007 the aircraft and its components shown in FIGS. 5-11 are substantially identical to the aircraft 100 and corresponding components shown in FIG. 1 (e.g., cruise propeller 510 is substantially identical to cruise propeller 110). during each stage, the components of the aircraft 100 are adjusted such that the center of gravity, the center of thrust, and the center of aerodynamic force may be substantially aligned.

Fig. 5 illustrates a taxi and climb configuration of a VTO L aircraft 100 according to one embodiment, stage 001 corresponds to a parked and taxi position of the aircraft 100, and stage 002 corresponds to a climb (e.g., vertical takeoff) configuration of the aircraft when the aircraft 100 is parked (e.g., when passengers enter or exit the aircraft 100), the stacked propellers (e.g., front stacked propeller 540a, rear stacked propeller 540b) may be stationary, and the wing tip pod 512 may be tilted upward such that it is perpendicular to the fuselage 535. the aircraft 100 may include one or more stacked propellers positioned along the aircraft (e.g., a starboard stacked propeller 515a, a port stacked propeller 515b, a front stacked propeller 540a, a rear stacked propeller 540b), as illustrated in fig. 5.

When the aircraft 100 is ready to take off, the stacked propellers (e.g., starboard stacked propeller 515a, port stacked propeller 515b, front stacked propeller 540a, rear stacked propeller 540b) may rotate and increase rotational speed until the aircraft 100 lifts off. During takeoff, i.e., phase 002, the nacelle 512 is held at a vertical angle of approximately 90 degrees to the fuselage 535 to enable the cruise propeller 510 to provide vertical lift. In one embodiment, during climb, the port and aft stacked propellers 515b, 540b rotate in a clockwise direction, while the starboard and forward stacked propellers 515a, 540a rotate in a counterclockwise direction.

As the propellers (e.g., starboard stacked propeller 515a, front stacked propeller 540a) rotate, boom control actuator 525 may remain in a neutral position. Alternatively, boom control actuators 525 may be angled to yaw the vehicle and direct airflow in a direction to stabilize aircraft 100 or otherwise direct aircraft 100. In most aircraft, the yaw motion is controlled by the rudder 657 of the aircraft. In one embodiment, yaw motion is partially or fully controlled by a boom control actuator 525. Yaw motion may also be controlled by a 5 degree to 10 degree rudder 557 located on the tail of the aircraft 100. The two surfaces may be angled to maintain the horizontal position of the aircraft during takeoff (e.g., the center of gravity, the thrust center, and the aerodynamic center are substantially aligned). The wing control surfaces 130 may be lowered by 40 degrees and the tail control surfaces 160 may be lowered by approximately 5 to 10 degrees to control aircraft pitch.

FIG. 6 illustrates an early transition-off configuration of VTO L aircraft 100 in accordance with one or more embodiments, the transition-off period, i.e., phase 003, transitions the aircraft from its climb state to its cruise state, as the aircraft 100 approaches cruise altitude, the aircraft 100 begins to transition from a vertical takeoff mode, i.e., phase 002, to a cruise configuration.

FIG. 7A illustrates a late-off-field transition configuration of VTO L aircraft 100 according to one embodiment, as the birds 712 and cruise propellers 710 continue to rotate downward until the birds 712 are substantially parallel to the fuselage 735, the aircraft 100 approaches the end of the off-field transition, i.e., stage 003, the stacked propellers (e.g., starboard stacked propeller 715a, port stacked propeller 715b, forward stacked propeller 740a, aft stacked propeller 740b) may continue to slow their rotation, and the first and second propellers of each stacked propeller may rotate at the same speed. the wing control surfaces 130 deflect to a neutral position while the tail control surfaces 160 remain in a neutral position.

Fig. 7B shows a top view of a blade 769 of a stacked propeller in a late-off-field transition, according to one embodiment. In fig. 7B, the first propeller 760 leads the second propeller 762 by an azimuth angle 766. As the propellers transition to cruise, the rotational speed of the propellers (e.g., first propeller 760, second propeller 762) may slow such that the azimuth angle 766 is zero and the blades 769 rotate at the same speed, as shown in the top view of fig. 7C. The propeller may stop rotating before retracting into the internal cavity of the rotor shaft.

FIG. 8 illustrates a cruise configuration of VTO L aircraft 100 according to one embodiment, the cruise configuration, i.e., stage 004, is generally characterized by stable, horizontal flight.wing control surfaces 130 and tail control surfaces 160 remain in a neutral position during cruise, nacelle 812 remains parallel to fuselage 835, allowing cruise propellers 810 to propel aircraft 100 at cruise speed (e.g., approximately 170 miles per hour). in one embodiment, left cruise propeller 810 rotates in a clockwise direction while right cruise propeller 810 rotates in a counterclockwise direction.

In the embodiment of fig. 8, the boom control actuator 825 and the rudder 857 remain in a neutral position during the cruise configuration. In particular, the stacked propellers (e.g., port stacked propeller 815b, aft stacked propeller 840b) may not rotate or may be recessed within the cavity such that the booms (e.g., wing booms 120, tail boom 145) may function for alternative purposes (e.g., storage). In a second embodiment, the boom control actuator 825 may be angled to control airflow behind the propeller. For example, a boom control actuator 825 may be attached to the cruise propeller 810. The cruise propeller 810 may be configured to a boom control actuator such that the boom control actuator has a suitable size and shape for directing the airflow duct behind the cruise propeller 810. During one mode of operation, the boom control actuator 825 may direct airflow behind the cruise propeller 810 such that the aircraft 100 follows a designated flight path and the noise generated by the cruise propeller 810 is mitigated. In embodiments where the boom control actuator is attached to the cruise propeller 810, the airflow behind the propeller may flow in a direction parallel to the aircraft fuselage. In this embodiment or another embodiment where the propeller is not a vertical propeller, the boom control actuator may be configured to control pitch and/or roll motions.

FIG. 9 illustrates an early approach transition configuration of VTO L aircraft 100 according to one embodiment, early approach transition, i.e., phase 005, transitions the aircraft from cruise phase 004 to descent phase 006, as aircraft 100 begins to transition from cruise to vertical descent, nacelle 912 and cruise propellers 910 begin to transition upward.

FIG. 10 illustrates a late approach transition configuration of VTO L aircraft 100 according to one embodiment, when nacelle 1012 and cruise propellers 1010 are rotated sufficiently such that nacelle 1012 is perpendicular to fuselage 135, aircraft 100 approaches the end of the transition, stage 005, stacked wing propellers (e.g., starboard stacked propeller 1015a, port stacked propeller 1015b) and stacked tail propellers (e.g., front stacked propeller 1040a, rear stacked propeller 1040b) begin to rotate and increase speed.

During early approach and late approach transitions of the aircraft (fig. 9-10), the boom control actuators (e.g., 925, 1025) may remain in a neutral position when the propellers are not rotating. In other embodiments, if the propeller begins to rotate, the boom control actuators (e.g., 925, 1025) may tilt to control yaw motion and/or reduce noise. In one embodiment, the boom control actuators (e.g., 925, 1025) may have the same angle relative to the axis of rotation. In other embodiments, the boom control actuators (e.g., 925, 1025) may have different angles to direct the airflow from the propellers relative to the axis of rotation of each propeller. Rudders (e.g., 957, 1057) attached to the tail of the aircraft may also remain in a neutral position during the approach transition period.

FIG. 11 illustrates a descent configuration of a VTO L aircraft 100 according to one embodiment, the descent phase 006 transitions the aircraft from an approach transition, phase 005 to a descent phase 007, as the aircraft 100 descends toward a descent region, the cruise propellers 1110 and stacked propellers (e.g., starboard stacked propellers 1115a, port stacked propellers 915b, front stacked propellers 1140a, rear stacked propellers 1140b) rotate to generate lift.

The description of the stacked propellers used by the entities of fig. 5-11 may vary depending on the implementation and requirements of the aircraft system. For example, an aircraft may include stacked propellers positioned along a fuselage or other region of the aircraft. The aircraft may include more or fewer stacked propellers than shown in fig. 5-11. The stacked propeller and/or the aircraft may lack some of the elements included in the above description. The operation of the stacked propeller is not limited to the description of fig. 5 to 11. For example, the boom control actuators may be tilted or neutral in an operating mode not described above, depending on the aircraft or environmental conditions.

Other considerations

These descriptions are presented for purposes of illustration; it is not intended to be exhaustive or to limit the invention to the precise form disclosed. One skilled in the relevant art will appreciate that many modifications and variations are possible in light of the above disclosure.

The language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based on this detailed description. Accordingly, the disclosure of embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention.