Aircraft with tiltable fuselage body

Abstract

1. An aircraft including a fuselage body, a front wing having two or more propulsion sources, and a rear wing having two or more propulsion sources, the front wing being located closer to a head portion of the fuselage body than the rear wing, and the rear wing being located closer to a tail portion of the fuselage body than the front wing, the aircraft being configured to apply a differential thrust between the front wing propulsion sources and the rear wing propulsion sources to generate a moment imbalance to tilt the fuselage body; and a method including applying a differential thrust between the front wing propulsion sources and the rear wing propulsion sources of the aircraft to generate a moment imbalance to tilt the fuselage body.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION

[0001] The embodiments described herein generally relate to aircraft having tiltable fuselage bodies. [Background technology]

[0002] The traditional solution for vertical takeoff and landing of aircraft has been the helicopter, which has design limitations in terms of range, performance and speed, as well as the complexity of the rotor mechanism (the cluster / cyclic rotor head is a mechanically complex element).

[0003]

[0003] More recently, multi-rotor "drones" have become popular in the small unmanned aerial vehicle (UAV) field. These are typically very small (less than 20 kg), made possible by advances in electric motor, speed controller, and battery technology. Lightweight electric motors allow for the necessary distribution of propulsion elements (where pistons or turbines would require multiple engines, with their significant weight penalty, or complex mechanical drive shaft mechanisms). However, this means that available power is becoming a limiting constraint in terms of range and endurance. This has typically limited these technologies to small aircraft.

[0004]

[0004] Recent developments driven by the urban air mobility sector (e.g., lightweight commercial air taxis), seeking to achieve vertical take-off / landing (VTOL) with the cruising benefits of traditional fixed-wing aircraft while also exploring the availability of greater electrical energy through both hybrid and potentially hydrogen-based solutions, have combined with interest from the UAV sector to create a wellspring of activity and innovation in combining VTOL and fixed-wing concepts.

[0005]

[0005] VTOL aircraft options generally fall into three categories.

[0006] Separate lift / cruise: Separate propulsion sources are used for vertical lift at takeoff and then for cruise. Typically these may involve some form of multicopter attached to a semi-conventional fixed-wing aircraft. These are simple in implementation but performance is burdened by the multiple propulsion sources.

[0007] Combined lift-cruise with tilting wings or rotors: This is a more advanced version of the lift / cruise concept where the same propulsion source is used for both vertical takeoff and conventional flight. The propulsion source's thrust lines are typically rotated from a vertical to a horizontal orientation by a tilting wing or rotor design. Examples include the V-22 Osprey, the Wisk UAM platform, etc. These platforms address the performance issues of separate lift-cruise configurations, but with significant complexity in the tilt mechanism.

[0008] Tail-sitter: A "traditional" aircraft "sits" vertically on its tail, using a large thrust-to-weight ratio to lift the vehicle off the ground and then rotate the entire body into a traditional aircraft flight attitude. While this provides the desired aerodynamic performance and efficiency, this configuration presents human factors challenges (e.g., the pilot sits aft for landing) and creates significant aircraft ground handling issues (e.g., if the tail-sitter has a sufficiently high center of gravity, the aircraft can be prone to tipping in the wind). Summary of the Invention

[0009] It would be desirable to provide an aircraft having a tiltable fuselage body. Additionally or alternatively, it would be desirable to provide industry with a useful option.

[0010]

[0007] In one aspect, an aircraft is provided that includes a fuselage body, a front wing having two or more propulsion sources ("forward wing propulsion sources"), and a rear wing having two or more propulsion sources ("rear wing propulsion sources"), the forward wing being located closer to a head portion of the fuselage body than the rear wing, and the rear wing being located closer to a tail portion of the fuselage body than the forward wing, and the aircraft is configured to apply differential thrust between the forward wing propulsion sources and the rear wing propulsion sources to generate a moment imbalance to tilt the fuselage body.

[0011] In some embodiments, each propulsion source and / or each wing is fixed in position relative to the fuselage body.

[0012] In some embodiments, tilting of the aircraft fuselage body tilts the propulsion source in conjunction with the fuselage body.

[0013] In some embodiments, the aircraft is configured to apply differential thrust by means of cambered front wings and cambered rear wings.

[0014]

[0011] In some embodiments, at least one propulsion source of the front wing is located on a thrust axis that is offset from the thrust axis of the propulsion source of the rear wing (to substantially avoid wake effects between the forward and rear propulsion sources).

[0015]

[0012] In some embodiments, at least one propulsion source on the rear wing is located on a thrust axis that is offset from the thrust axis of the propulsion source on the front wing (to substantially avoid wake effects between the forward and rear propulsion sources).

[0016] In some embodiments, the propulsion source of the aircraft comprises: A net forward thrust is exerted by the canard thrust source (along its thrust axis to exert an upward force on the head portion of the fuselage), and / or A net reverse thrust is exerted by the rear wing thrust source (along its thrust axis to exert a downward force on the tail section of the fuselage) When the rotor is in a rotating position, the rotor is configured to apply a differential thrust to generate a moment imbalance.

[0017] In some embodiments, the propulsion source of the aircraft comprises: A net reverse thrust is exerted by the forewing thrust source (along its thrust axis to exert a downward force on the head portion of the fuselage), and / or A net forward thrust is exerted by the rear wing thrust source (along its thrust axis to exert an upward force on the tail section of the fuselage) When the rotor is in a rotating position, the rotor is configured to apply a differential thrust to generate a moment imbalance.

[0018] In some embodiments, the propulsion source of the aircraft comprises: a first net forward thrust is exerted by the canard thrust source (along its thrust axis to exert an upward force on the head portion of the fuselage); and A second net forward thrust is exerted by the rear wing thrust source (along its thrust axis to exert an upward force on the tail section of the fuselage). and applying a differential thrust to generate a moment imbalance when Here, the second net forward thrust is less than the first net forward thrust for the first differential thrust (to tilt the fuselage body from a stationary configuration to a tail-sitting configuration before takeoff and / or to tilt the fuselage body to provide pitch control in flight); or The second net forward thrust is greater than the first net forward thrust for the first differential thrust (to tilt the fuselage body from a tail-sitting configuration to a stationary configuration after landing and / or to tilt the fuselage body to provide pitch control during flight).

[0019]

[0016] In some embodiments, the aircraft includes at least one wheel, preferably two or more wheels (e.g., configured to be pivoted by the fuselage body of the aircraft when tilting between a stationary configuration and a tail-sitting configuration).

[0020] In some embodiments, the aircraft includes brakes for braking the wheels (eg, when tilting between a stationary configuration and a tail-sitting configuration).

[0021] In some embodiments, at least one propulsion source is angled relative to the horizontal when the aircraft is in a stationary configuration (including, for example, a forward propulsion source, by up to substantially 5 degrees).

[0022]

[0019] In some embodiments, each propulsion source is configured to provide lift for takeoff and thrust for cruise.

[0023] In some embodiments, the aircraft is configured to apply differential thrust to tilt the fuselage body to provide pitch control during flight.

[0024] In some embodiments, the aircraft is configured to apply differential thrust to tilt the fuselage body between a stationary configuration and a tail-sitting configuration.

[0025]

[0022] Tilting the fuselage body between the rest configuration and the tail-sitting configuration includes: tilting the fuselage body from a stationary configuration to a tail-sitting configuration before takeoff; and / or · may include tilting the fuselage body from a tail-sitting configuration to a stationary configuration after landing.

[0026]

[0023] In some embodiments, the front wings are mounted closer to the underside of the fuselage body than the rear wings, and the rear wings are mounted closer to the upper surface of the fuselage body than the front wings.

[0027] In some embodiments, the front and / or rear wings are cranked, with the front wings having a cranked anhedral angle and / or the rear wings having a cranked dihedral angle.

[0028] In some embodiments, the canards are a canard pair including a first left wing having at least one propulsion source and a first right wing having at least one propulsion source.

[0029] In some embodiments, the rear wing is a rear wing pair including a second left wing having at least one propulsion source and a second right wing having at least one propulsion source.

[0030]

[0027] In some embodiments, the wings are foldable.

[0031] In some embodiments, the aircraft includes two or more wheels, preferably four wheels.

[0032] In some embodiments, the aircraft is configured to take off at an inclination ranging from 65 degrees to vertical relative to the horizontal.

[0033] In some embodiments, the aircraft is configured to take off substantially vertically from a tail-sitting configuration.

[0034] In some embodiments, the aircraft is configured to take off at an inclination of between 65 and 70 degrees relative to the horizontal.

[0035] In some embodiments, the aircraft is configured to land substantially vertically so as to be in a tail-sitting configuration.

[0036] In some embodiments, the aircraft is configured to land at an inclination of between 65 and 70 degrees relative to the horizontal.

[0037] In some embodiments, the aircraft includes a control system for operating the aircraft remotely and / or autonomously.

[0038] In some embodiments, the aircraft is configured to carry a payload of 150 kg or more.

[0039]

[0036] In another aspect, a method is provided that includes applying differential thrust between forward and aft wing thrust sources of an aircraft to create a moment imbalance to tilt a fuselage body.

[0040] In some embodiments, each propulsion source and / or each wing of the aircraft is fixed in position relative to the fuselage body.

[0041] In some embodiments, tilting of the aircraft fuselage body tilts the propulsion source in conjunction with the fuselage body.

[0042]

[0039] In some embodiments, the method includes applying differential thrust with a cambered front wing and a cambered rear wing.

[0043]

[0040] In some embodiments, the method further includes applying a differential thrust to tilt the fuselage body between the stationary configuration and the tail-sitting configuration.

[0044]

[0041] In some embodiments, the method further includes applying differential thrust to tilt the fuselage body to provide pitch control during flight.

[0045]

[0042] In another aspect, there is provided an aircraft including a fuselage body, a down-cambered front wing having two or more thrust sources, and an up-cambered rear wing having two or more thrust sources, the front wing being located closer to a head portion of the fuselage body than the rear wing, and the rear wing being located closer to a tail portion of the fuselage body than the front wing, and the aircraft configured to apply differential thrust between the thrust sources of the front wing and the thrust sources of the rear wing to generate a moment imbalance to tilt the fuselage body.

[0046]

[0043] In some embodiments, the cambered front wing provides at least one propulsion source on the front wing with lever arm separation from the propulsion source on the rear wing to facilitate moment imbalance to tilt the fuselage body.

[0047]

[0044] In some embodiments, the cambered rear wing provides at least one propulsion source on the rear wing with lever arm separation from the propulsion source on the front wing to facilitate moment imbalance to tilt the fuselage body.

[0048]

[0045] In another aspect, a method (of aircraft control) is provided that includes applying a differential thrust between a cambered front wing propulsion source and a cambered rear wing propulsion source of an aircraft to create a moment imbalance to tilt a fuselage body.

[0049] In some embodiments, the method comprises: Applying differential thrust to tilt the fuselage body between a stationary configuration and a tail-sitting configuration; and / or · Involves applying differential thrust to tilt the fuselage body to provide pitch control in flight.

[0050] As used herein, "wing" may refer to a single wing or a pair of wings, depending on the context. For example, a "forewing" may refer to a unitary wing extending below / across the fuselage body in both port and starboard directions. However, "forewing" may also be used collectively to refer to a pair of wings, such that one wing portion extends from the fuselage body in a port direction and another wing portion extends from the fuselage body in a starboard direction. [Brief explanation of the drawings]

[0051] [Figure 1A] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 1B] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 1C] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 1D] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 1E] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 2A] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 2B] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 2C] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 2D] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 2E] FIG. 1 illustrates an exemplary aircraft embodiment. [Figure 3]

[0050] Figure 3 illustrates a sequence of tilting of an exemplary aircraft embodiment from a stationary configuration to a tail-sitting configuration. [Figure 4]

[0051] A diagram illustrating the sequence of an exemplary aircraft embodiment taking off from a tail-sitting configuration and transitioning to cruise. [Figure 5]

[0052] FIG. 2 illustrates a sequence for an exemplary aircraft embodiment transitioning from cruise to landing into a tail-sitting configuration. [Figure 6]

[0053] FIG. 2 illustrates a tilt sequence of an exemplary aircraft embodiment from a tail-sitting configuration to a stationary configuration. [Figure 7]

[0054] 4 is a force diagram of an exemplary aircraft embodiment illustrating how moment imbalance is generated; [Figure 8]

[0055] FIG. 1 illustrates an exemplary application of how an embodiment of an aircraft may be used. DETAILED DESCRIPTION OF THE INVENTION

[0052]

[0056] Embodiments described herein may be said to relate to an improved aircraft (e.g., FIGS. 1A-1E and 2A-2E ). The aircraft includes a fuselage body. The aircraft also includes a canard having two or more propulsion sources. The aircraft also includes a rear wing having two or more propulsion sources. The canard is located closer to a head portion of the fuselage body than the rear wing. The rear wing is located closer to a tail portion of the fuselage body than the canard. The aircraft is configured to apply differential thrust between the canard propulsion source and the rear wing propulsion source. The applied differential thrust assists in generating a moment imbalance to tilt the fuselage body. For example, the differential thrust assists in generating a moment imbalance to tilt the fuselage body from a resting configuration to a tail-sitting configuration (as shown in FIG. 3 ). In some embodiments, the differential thrust assists in generating a moment imbalance to tilt the fuselage body to provide pitch control during flight.

[0053]

[0057] In some embodiments, the aircraft is configured to take off vertically (or nearly vertically) from a tail-sitting configuration (e.g., FIG. 4). In some embodiments, the aircraft is configured to transition from (nearly) vertical takeoff to (horizontal) cruise (e.g., FIG. 4). In some embodiments, the aircraft is configured to transition from (horizontal) cruise to (nearly) vertical landing (e.g., FIG. 5). In some embodiments, the aircraft is configured to land vertically (or nearly vertically) to a tail-sitting configuration (e.g., FIG. 5). In some embodiments, the aircraft is configured to apply differential thrust between the forward and rear wing propulsion sources, which assists in creating a moment imbalance to tilt the fuselage body from the tail-sitting configuration to a static configuration (e.g., as shown in FIG. 6) and to tilt the fuselage body to provide pitch control during flight.

[0054]

[0058] A first exemplary embodiment will now be described first, by way of example, with reference to Figures 1A-1E, and then another exemplary embodiment will be described later, by way of example, with reference to Figures 2A-2E.

[0055]

[0059] 1A-1E show diagrams of one exemplary embodiment of an aircraft 10. 1A-1C show various views of the aircraft 10 in a stationary configuration, 1D shows the aircraft 10 in a tail-sitting configuration, and 1E shows the aircraft 10 in a level cruise configuration. The aircraft according to this exemplary embodiment is a tandem aircraft. That is, the aircraft has a fuselage body 12, front wings 14a-b, and rear wings 16a-b.

[0056]

[0060] In this particular exemplary embodiment, the canerodile 14a-b is cranked (i.e., includes an angular change along its span). The canerodile 14 includes a forward port wing section 14a (which may be referred to herein as the "forward port section") and a forward starboard wing section 14b (which may be referred to herein as the "forward starboard section"). The canerodile is cambered. The canerodile has two propulsion sources 18a-b. That is, the canerodile 14 has a port propulsion source 18a located on the forward port section 14a (which may be referred to herein as the "left propulsion source") and a starboard propulsion source 18b located on the forward starboard section 14b (which may be referred to herein as the "starboard propulsion source").

[0057]

[0061] The rear wings 16a-b are located closer to and connected to the top of the fuselage body 12 than the front wings 14a-b. The rear wings 16a-b include an aft port portion 16a (which may be referred to herein as the "aft port portion") and an aft starboard portion 16b (which may be referred to herein as the "aft starboard portion"). The rear wings 16a-b are cambered. The rear wings have two propulsion sources 20a-b: a port propulsion source 20a located on the aft port portion 16a (which may be referred to herein as the "left propulsion source") and a starboard propulsion source 20b located on the aft starboard portion 16b (which may be referred to herein as the "right propulsion source").

[0058]

[0062] The propulsion sources 18a-b for the front wings 14a-b are fixed in position so as not to rotate relative to the front wings 14a-b or relative to the fuselage body 12. Similarly, the propulsion sources 20a-b for the rear wings 16a-b are fixed in position so as not to rotate relative to the rear wings 16a-b or relative to the fuselage body 12. That is, when the fuselage body 12 tilts, the propulsion sources 18a-b, 20a-b for the front and rear wings tilt in unison with the fuselage body 12. The propulsion sources on the aircraft 10 are propellers. The ability to facilitate vertical takeoff without having to allow for relative rotation of the propulsion sources (with respect to the wings and fuselage body) makes the aircraft design mechanically simpler because the design does not require moving joints that inherently transmit large forces.

[0059]

[0063] The aircraft 10 according to this particular exemplary embodiment has multiple wheels 22a-b. In this exemplary embodiment, the aircraft has four wheels 22a-d, including two front wheels 22a and two rear wheels 22b. In the stationary configuration shown in FIGS. 1A-1C, the aircraft 10 rests on all four wheels 22a-b. Having two front wheels 22a and two rear wheels 22b helps provide stability in the stationary configuration. In the tail-sitting configuration shown in FIG. 1D, the aircraft 10 rests on the rear wheels 22b. The rear wheels 22b provide stability as the aircraft 10 tilts between the stationary and tail-sitting configurations by providing a fixed axis on which the aircraft 10 pivots while tilting. While the non-limiting example shown in FIGS. 1A-1D shows two front wheels and two rear wheels, it is possible to have a single front wheel and / or a single rear wheel instead. In alternative design variations, there may be three or more front wheels and / or three or more rear wheels.

[0060]

[0064] 2A-2E show diagrams of another exemplary embodiment of aircraft 10. The embodiment according to FIGS. 2A-2E has, for the most part, the same features and functionality as the exemplary embodiment described by FIGS. 1A-1E. For example, the illustrated exemplary embodiment has a stationary configuration (FIGS. 2A-2E), a tail-sitting configuration (not shown), and a cruise configuration (not shown). However, some differences exist.

[0061] One difference is that, as can be seen in FIG. 1B, the first exemplary embodiment has a "crank" 24a, 24b in the canard camber (the angular change along the span of each wing 14a, 14b) (and a relatively low camber) and an undercarriage attached to the canard, which reduces the canard camber and, as a result, can improve the lateral stability of the aircraft and also provide greater clearance for fuselage loads. In contrast, each canard 14a, 14b of the second exemplary embodiment is substantially straight, as can be seen in FIG. 2B.

[0062] Another difference is that the second exemplary embodiment has a larger front wing camber (compared to the first exemplary embodiment), allowing for the elimination of the camber crank, while still maintaining the required propeller separation between the front and rear wings. The undercarriage is also shown mounted to the main fuselage, providing a simpler structural design for the wing.

[0063] Another difference is that each of the propulsion sources 18a-b, 20a-b in the first exemplary embodiment is a propeller with two blades, and each of the propulsion sources 18a-b, 20a-b in the second exemplary embodiment is a propeller with three blades.

[0064]

[0065] Both the exemplary embodiment of FIGS. 1A-1E and the exemplary embodiment of FIGS. 2A-2E have a tiltable fuselage body 12, which allows the fuselage body 12 to tilt from a static configuration to a tail-sitting configuration (e.g., in the manner shown sequentially in FIG. 3 ), allowing the fuselage body to tilt to provide pitch control during flight. Tilting of the fuselage body 12 is achieved by applying differential thrust between the forward wing propulsion sources 18 a-b and the rear wing propulsion sources 20 a-b. The differential thrust creates a moment imbalance within the fuselage body 12 that forces the fuselage body 12 to tilt from a static configuration to a tail-sitting configuration, and forces the fuselage body to tilt to provide pitch control during flight. This will be described in more detail hereinafter. The exemplary embodiment may additionally or alternatively be configured to apply differential thrust between the forward and aft wing propulsion sources 18a-b and 20a-b to create a moment imbalance within the fuselage body 12 to tilt the fuselage body 12 from a tail-sitting configuration to a stationary configuration (e.g., in the manner shown sequentially in FIG. 6 ) and to tilt the fuselage body to provide pitch control in flight, as will also be described in more detail hereinafter.

[0065]

[0066] 1A-1E and 2A-2E, it is contemplated that additional embodiments may be designed to apply differential thrust between the forward and aft wing propulsion sources 18a-b and 20a-b to create a moment imbalance within the fuselage body 12 so that the fuselage body 12 tilts from a stationary configuration to a tail-sitting configuration (and / or vice versa) and to tilt the fuselage body to provide pitch control in flight. Such additional embodiments may vary with respect to aircraft performance, ground handling, and / or design complexity, as will be described in more detail hereinafter.

[0066]

[0067] 3(A-C), for example, some aircraft embodiments 10 are configured to apply differential thrust between the forward wing propulsion sources 18a-b and the aft wing propulsion sources 20a-b to create a moment imbalance within the fuselage body 12 to tilt the fuselage body 12 from a static configuration to a tail-sitting configuration and to tilt the fuselage body to provide pitch control in flight, as will be described in more detail hereinafter.

[0067]

[0068] 4, by way of example, some aircraft embodiments 10 may be configured to take off vertically (or near-vertically) from a tail-sitting configuration. The propulsion sources 18a-b, 20a-b used to tilt the fuselage body from a stationary configuration to a tail-sitting configuration may also be used to propel a vertical (or near-vertical) takeoff. In some embodiments, the aircraft 10 is configured to take off at an inclination ranging from 65 degrees to vertical relative to the horizontal. In some embodiments, the aircraft 10 is configured to take off substantially vertically from a tail-sitting configuration. In some embodiments, the aircraft 10 is configured to take off at an inclination between 65 degrees and 70 degrees relative to the horizontal.

[0068]

[0069] 4 by way of example, some aircraft embodiments 10 may be configured to transition from vertical flight (e.g., similar to a quadcopter) to horizontal flight (similar to a conventional canard-equipped fixed-wing aircraft). There are several methods for transitioning from vertical to horizontal flight with varying degrees of trade-off between altitude, speed, and stability. The propulsion sources 18a-b, 20a-b used to tilt the fuselage body 12 from a stationary configuration to a tail-sitting configuration may also be used to provide thrust during cruise and horizontal flight, and to provide pitch and yaw control during vertical flight.

[0069]

[0070] 5, for example, some aircraft embodiments 10 may be configured to transition from horizontal flight (in which it behaves like a conventional canarded fixed-wing aircraft) to vertical flight (in which it behaves like a quadcopter). There are several ways to perform this maneuver with varying degrees of trade-off between altitude, speed, and stability. Propulsion sources 18a-b, 20a-b may be used to tilt fuselage body 12 from a horizontal flight configuration (in which it behaves like a conventional canarded fixed-wing aircraft, e.g., of FIGS. 5(A-C)) to a vertical flight configuration (in which it behaves like a quadcopter, e.g., of FIGS. 5(D-E)) in preparation for landing in a tail-sitting configuration (e.g., of FIG. 5(F)).

[0070]

[0071] Again, referring back to FIG. 5 by way of example, some aircraft embodiments may be configured to land vertically (or near vertically) so as to assume a tail-sitting configuration. The propulsion sources 18a-b, 20a-b used to tilt the fuselage body 12 from a stationary configuration to a tail-sitting configuration may also be used to assist in a vertical (or near vertical) landing. In some embodiments, the aircraft 10 is configured to land at an inclination ranging from 65 degrees to vertical relative to the horizontal. In some embodiments, the aircraft 10 is configured to land substantially vertically so as to assume a tail-sitting configuration. In some embodiments, the aircraft 10 is configured to land at an inclination between 65 degrees and 70 degrees relative to the horizontal.

[0071]

[0072] 6, by way of example, some aircraft embodiments 10 may be configured to apply a differential thrust between the forward wing propulsion sources 18a-b and the aft wing propulsion sources 20a-b to create a moment imbalance within the fuselage body 12 such that the fuselage body tilts from a tail-sitting configuration to a stationary configuration, as will be described in more detail hereinafter.

[0072]

[0073] The discussion then turns to implementation and related design considerations. In particular, a description is provided of how the aircraft 10 can be configured to apply differential thrust between the front wing thrust sources 18a-b and the rear wing thrust sources 20a-b to create a moment imbalance to tilt the fuselage body 12.

[0073]

[0074] As mentioned, tilt of the fuselage body 12 is caused by creating a moment imbalance within the fuselage body 12. The moment imbalance is created as a result of differential thrust exerted by the thrust sources. That is, the thrust exerted by the forward thrust source is different from the thrust exerted by the aft thrust source. This thrust difference can be a difference in magnitude and / or direction.

[0074]

[0075] The relative positioning of the propulsion sources in angle and location also assists in creating moment imbalance when differential thrust is applied. That is, it is the proper relative positioning of the propulsion sources combined with the applied differential thrust that results in a moment imbalance for tilting the fuselage body. For clarity, the angle of the propulsion source refers to the direction of the thrust axis of the propulsion source (the thrust axis is perpendicular to the disk plane of the propulsion source). Aircraft features related to the positioning of the propulsion sources may include, for example, but are not limited to:

[0075] The angle of the propulsion source relative to the horizontal plane (e.g., the ground) in a stationary configuration (to allow for tilting in a tail-sitting configuration).

[0076] · Relative angular offset between the front and rear wing thrust sources.

[0077] The relative displacement offset of the forward thrust source relative to the rear thrust source (longitudinal along the longitudinal axis of the fuselage body and / or transverse along the z-axis of the fuselage body).

[0078] Wing design can also aid in the relative positioning of the propulsion sources. For example, referring back to the exemplary embodiments of FIGS. 1A-1E and 2A-2E, both embodiments have a combination of a cambered front wing and a cambered rear wing. Additionally, the cambered front wing is mounted closer to the underside of the fuselage body than the cambered rear wing, and the cambered rear wing is mounted closer to the upper surface of the fuselage body than the cambered front wing. The cambered-cambered wing configuration positions the propulsion sources such that the front wing propulsion source is located lower (along the fuselage body height axis, i.e., along the fuselage body z-axis) than the rear wing propulsion source, and the rear wing propulsion source is located higher (along the fuselage body height axis, i.e., along the fuselage body z-axis) than the front wing propulsion source. In this particular example, the exemplary wing design aids in placing the propulsion sources in the appropriate locations to generate moment imbalance due to the applied differential thrust.

[0079]

[0077] The use of a stable pivot (along the width of the fuselage body) can also assist in tilting the fuselage body when a moment imbalance is generated. One way to achieve this is to use the rear wheels 22b as stable pivots (along the width of the fuselage body) for pivoting on when the fuselage body tilts. Optionally, rear wheel brakes can be added to provide fixed pivots (along the width of the fuselage body) for pivoting on when the fuselage body tilts. That is, having a stable or fixed pivot reduces the possibility of the pivot moving longitudinally with the fuselage body when it tilts. While two rear wheels are preferred to allow the fuselage body to pivot, any number of rear wheels may alternatively be selected for pivoting the fuselage body.

[0080]

[0078] Some exemplary features for creating moment imbalance to tilt the fuselage body may include, but are not limited to:

[0081] Offsetting the thrust axis of the leading thrust source from the thrust axis of the trailing thrust source. This offset may represent a displacement offset and / or a directional offset.

[0082] · Use of cambered front wings and / or cambered rear wings so that there is an offset in displacement and / or direction between the thrust axis of the front wing thrust source and the aft force axis of the rear wing thrust source.

[0083] · Mounting the front wings closer to the underside of the fuselage body compared to the rear wings so that there is an offset in displacement and / or direction between the thrust axis of the front wing propulsion source and the aft force axis of the rear wing propulsion source.

[0084] · The rear wing is mounted closer to the upper surface of the fuselage body compared to the front wing so that there is an offset in displacement and / or direction between the thrust axis of the front wing propulsion source and the aft force axis of the rear wing propulsion source.

[0085] For example, causing the canard thrust source to exert a net forward thrust (along its thrust axis) relative to the rear thrust source to exert a net upward force on the head portion of the fuselage body to tilt the fuselage body from a stationary configuration to a tail-sitting configuration.

[0086] For example, causing the rear wing thrust source to exert a net opposite thrust (along its thrust axis) relative to the forearm thrust source to exert a net downward force on the tail portion of the fuselage body to tilt the fuselage body from a stationary configuration to a tail-sitting configuration.

[0087] For example, causing the forward thrust source to exert a net opposite thrust (along its thrust axis) relative to the rear thrust source to exert a net downward force on the head portion of the fuselage body to tilt the fuselage body from a tail-sitting configuration to a stationary configuration.

[0088] For example, causing the rear wing thrust source to exert a net forward thrust (along its thrust axis) relative to the forearm thrust source to exert a net upward force on the tail portion of the fuselage body to tilt the fuselage body from a tail-sitting configuration to a stationary configuration.

[0089] having a first net forward thrust exerted by a thrust source on the front wing (along its thrust axis to exert an upward force on the head portion of the fuselage) and a second net forward thrust exerted by a thrust source on the rear wing (along its thrust axis to exert an upward force on the tail portion of the fuselage), thereby (to tilt the fuselage) i. the second net forward thrust is less than the first net forward thrust for the first differential thrust (to tilt the fuselage body from a stationary configuration to a tail-sitting configuration before takeoff and / or to tilt the fuselage body to provide pitch control in flight); or ii. the second net forward thrust is greater than the first net forward thrust for the first differential thrust (to tilt the fuselage body from a tail-sitting configuration to a stationary configuration after landing and / or to tilt the fuselage body to provide pitch control in flight).

[0090] The rear wheels are used to provide a stable axis about which the fuselage body pivots on the ground when a moment imbalance is created and the fuselage body tilts. Preferably, the rear wheels are also braked to reduce movement in the axis about which the fuselage body pivots. More preferably, braking the rear wheels creates a fixed or nearly fixed pivot axis.

[0091] Offset the angle of the propulsion source from horizontal when the aircraft is in a stationary configuration. One or more of the described exemplary features may be combined to achieve the desired effect of creating a moment imbalance to tilt the fuselage body.

[0092]

[0079] Figure 7 shows a force diagram for aircraft embodiment 10 having the following axes, forces and dimensions, the forces and dimensions selected to have, for example, example values ​​in the table below to provide example characteristics for generating moment imbalance:

[0093] [Table 1-1] [Table 1-2] [Table 1-3] [Table 1-4] [Table 1-5]

[0094] In embodiments, The lever arms Tzf and Tzr may be maximized to increase the differential moment to aid in rotation and controllability for tailsitter when in quadcopter mode, this can be achieved by setting the wing tilts Wdf and Wdr so that the front wings are cambered and the rear wings are cambered.

[0095] The thrust wakes (z-axis) between the forward and aft propulsion sources may preferably be substantially separated to improve the efficiency of the propulsion source, while ensuring that there is substantially no overlap between the forward and aft propellers when viewed along the thrust axis (e.g., as seen by FIG. 2E).

[0096] The wings can be substantially separated (along the Z axis) between the front and rear wings to minimize aerodynamic interactions during cruise flight.

[0097] · The net total height of the vehicle in its resting orientation can be minimized, since the higher the vehicle and its center of gravity, the less stable the vehicle will be when on the ground.

[0098] Wheel base can be maximized for ground handling and stability on the ground.

[0099] Net thrust parallel to the ground surface can be minimized to reduce the possibility of translation.

[0100] · Because propulsion sources are more efficient and less prone to failure when producing forward thrust, the amount of reverse thrust can be minimized.

[0101] · The angular tilt of the thrust vector when in the stationary orientation can be maximized to reduce translational forces.

[0102] The area of ​​the fuselage perpendicular to the cruise flight orientation can be minimized to minimize drag (to increase range, endurance, and maximum speed).

[0103] Wing camber and deflection may be limited to ensure adequate aerodynamic performance and lateral stability when in cruise mode.

[0104] To provide for the foregoing, an aircraft 10 is described herein, the aircraft including a fuselage body 12, front wings 14a-b having two or more propulsion sources 18a-b, and rear wings 16a-b having two or more propulsion sources 20a-b. The front wings 14a-b are located closer to a head portion of the fuselage body 12 than the rear wings 16a-b, and the rear wings 16a-b are located closer to a tail portion of the fuselage body 12 than the front wings 14a-b. The aircraft 10 is configured to apply differential thrust between the front wing propulsion sources 18a-b and the rear wing propulsion sources 20a-b to generate a moment imbalance to tilt the fuselage body 12.

[0105] In some embodiments, the aircraft 10 is configured to apply a differential thrust between the forward wing propulsion sources 18a-b and the rear wing propulsion sources 20a-b to generate a moment imbalance to tilt the fuselage body 12 from a stationary configuration to a tail-sitting configuration. Additionally or alternatively, the aircraft 10 is configured to apply a differential thrust between the forward wing propulsion sources 18a-b and the rear wing propulsion sources 20a-b to generate a moment imbalance to tilt the fuselage body 12 from a tail-sitting configuration to a stationary configuration. The ability to tilt the aircraft from a stationary configuration to a tail-sitting configuration (such that the aircraft is immediately capable of (near) vertical takeoff) and / or vice versa avoids the ground handling difficulties associated with tail-sitting aircraft when the aircraft is stationary, while retaining the ability of the aircraft to take off in a near-vertical orientation in a manner similar to conventional tail-sitting aircraft. The tilting body mechanism therefore provides a solution for an aircraft that can take off from confined spaces (e.g., where no runway is present) while making logistical handling on the ground easier compared to conventional tail-sitting aircraft. Furthermore, the static configuration of the aircraft means that the aircraft has a lower center of gravity compared to conventional tail-sitter aircraft at rest. The lower center of gravity provided by the static configuration provides improved stability (e.g., the aircraft is less likely to be blown over by wind) relative to an aircraft at rest.

[0106] In some embodiments, each propulsion source 18a-b, 20a-b and / or each wing 14a-b, 16a-b is fixed in position relative to the fuselage body 12. In some embodiments, tilting of the fuselage body 12 of the aircraft 10 causes the propulsion sources 18a-b, 20a-b to tilt in conjunction with the fuselage body 12. Because differential thrust exerted by the propulsion sources 18a-b, 20a-b of the aircraft 10 generates a moment imbalance to tilt the fuselage body 12 (e.g., from a stationary configuration to a tail-sitting configuration), it is not necessary for the aircraft 10 to rotate its propulsion sources 18a-b, 20a-b relative to the wings 14a-b, 16a-b and / or fuselage 12 (e.g., for vertical takeoff). The absence of rotating propulsion sources 18a-b, 20a-b and rotating wings 14a-b, 16a-b consequently simplifies the overall design of the aircraft 10.

[0107] In some embodiments, at least one propulsion source 18a-b on the leading wing is located on a thrust axis that is offset from the thrust axis of the propulsion sources 20a-b on the trailing wing. In some embodiments, at least one propulsion source 20a-b on the trailing wing is located on a thrust axis that is offset from the thrust axis of the propulsion sources 18a-b on the leading wing.

[0108] That is, the moment imbalance used to tilt the fuselage body 12 is created by the relative positioning of the propulsion sources 18a-b, 20a-b. In particular, the offset of the rotational axes between the forward and rearward wing propulsion sources 18a-b, 20a-b assists in creating the moment imbalance to tilt the fuselage body 12. In some embodiments, the propulsion sources 18a-b, 20a-b of the aircraft 10 are configured to apply differential thrust to generate a moment imbalance (to tilt the fuselage body from a stationary configuration to a tail-sitting configuration and to provide pitch control in flight) when a net forward thrust is exerted by the forward wing propulsion sources 18a-b (along their thrust axes to exert an upward force on the head portion of the fuselage) and / or a net reverse thrust is exerted by the rearward wing propulsion sources 20a-b (along their thrust axes to exert a downward force on the tail portion of the fuselage). In some embodiments, the propulsion sources 18a-b, 20a-b of the aircraft 10 are configured to apply differential thrust to create a moment imbalance (along their thrust axes to tilt the fuselage body from a tail-sitting configuration to a stationary configuration and to provide pitch control in flight) when a net reverse thrust is being applied by the forward wing propulsion sources 18a-b (along their thrust axes to apply a downward force on the head portion of the fuselage) and / or a net forward thrust is being applied by the rear wing propulsion sources 20a-b (along their thrust axes to apply an upward force on the tail portion of the fuselage).In some embodiments, the propulsion sources 18a-b, 20a-b of the aircraft 10 are configured to exert differential thrust to create a moment imbalance when a first net forward thrust is exerted by the forward wing propulsion sources (along their thrust axes to exert an upward force on the head portion of the fuselage) and a second net forward thrust is exerted by the rear wing propulsion sources (along their thrust axes to exert an upward force on the tail portion of the fuselage), wherein the second net forward thrust is less than the first net forward thrust for the first differential thrust (to tilt the fuselage body from a stationary configuration to a tail-sitting configuration before takeoff and / or to provide pitch control during flight) or the second net forward thrust is greater than the first net forward thrust for the first differential thrust (to tilt the fuselage body from a tail-sitting configuration to a stationary configuration after landing and / or to provide pitch control during flight).

[0109] In some embodiments, the aircraft 10 includes at least one wheel, preferably two or more wheels 22b, configured to be pivoted by the fuselage body 12 of the aircraft 10 (e.g., when tilting between a stationary configuration and a tail-sitting configuration). In some embodiments, the aircraft 10 includes brakes for braking the wheels 22b (e.g., when tilting between a stationary configuration and / or a tail-sitting configuration). The use of wheels (e.g., rear wheels) and optionally brakes can help facilitate a stable, fixed longitudinal pivot point (i.e., a pivot point that does not move while the fuselage body is tilting) to provide reliable takeoff / touchdown, particularly in adverse environmental conditions (e.g., wind, gusts, and ground slopes (including moving ship decks)).

[0110] In some embodiments, at least one propulsion source 18a-b, 20a-b is angled relative to the horizontal when the aircraft 10 is in a stationary configuration. In some embodiments, the front wings 14a-b are cambered and the rear wings 16a-b are cambered.

[0111] In some embodiments, the front wings 14a-b are mounted closer to the underside of the fuselage body 12 than the rear wings 16a-b, and the rear wings 16a-b are mounted closer to the upper surface of the fuselage body 12 than the front wings 14a-b. Such relative positioning of the wings 14a-b, 16a-b contributes to a lever arm difference between the front wings 14a-b and the rear wings 16a-b. The lever arm difference helps to decouple the aerodynamic interactions between the front wings 14a-b and the rear wings 16a-b. Additionally, the lever arm difference means that it is possible to reduce the extent of the downturn of the front wings 14a-b and / or reduce the extent of the upturn of the rear wings 16a-b.

[0112] Also described herein are methods that include applying differential thrust between forward wing propulsion sources 18a-b and aft wing propulsion sources 20a-b of an aircraft 10 to create a moment imbalance to tilt the fuselage body 12. In some embodiments, each propulsion source and / or each wing of the aircraft is fixed in position relative to the fuselage body. In some embodiments, tilting the fuselage body of the aircraft tilts the propulsion sources in conjunction with the fuselage body. In some embodiments, the method includes applying differential thrust with a cambered forward wing and a cambered aft wing. In some embodiments, the method includes applying differential thrust to tilt the fuselage body 12 between a stationary configuration and a tail-sitting configuration. In some embodiments, the method includes applying differential thrust to tilt the fuselage body 12 to provide pitch control during flight.

[0113] Also described herein is an aircraft 10 including a fuselage body 12, down-cambered front wings 14a-b having two or more thrust sources 18a-b, and up-cambered rear wings 16a-b having two or more thrust sources 20a-b. The front wings 14a-b are located closer to the head of the fuselage body 12 than the rear wings 16a-b, and the rear wings 16a-b are located closer to the tail of the fuselage body 12 than the front wings 14a-b. The aircraft 10 is configured to apply differential thrust between the front wing thrust sources 18a-b and the rear wing thrust sources 20a-b to generate a moment imbalance to tilt the fuselage body 12. In some embodiments, the cambered front wings 14a-b provide at least one propulsion source 18a-b on the front wings 14a-b with a lever arm separation from the propulsion sources 20a-b on the rear wings 16a-b to facilitate moment imbalance to tilt the fuselage body 12. In some embodiments, the cambered rear wings 16a-b provide at least one propulsion source 20a-b on the rear wings 16a-b with a lever arm separation from the propulsion sources 18a-b on the front wings 14a-b to facilitate moment imbalance to tilt the fuselage body 12.

[0114] In the context of designing one or more disclosed embodiments of the aircraft 10, having a combination of cambered front wings 14a-b and cambered rear wings 16a-b serves to increase the lever arm force for generating the associated moment imbalance to tilt the fuselage body, for example, between a stationary configuration and a tail-sitting configuration. See, for example, lever arms Tzf and Tzr in the aircraft force diagram of FIG. 7. Having at least two wings and cambered front wings and cambered rear wings is considered unusual. This is because cambered wing designs are often avoided in conventional aircraft design due to the lateral stability issues associated with cambered wings, which are well known in the art. Furthermore, tandem (double) wing combinations are also avoided in conventional aircraft design because such designs present several aerodynamic and structural challenges, well known in the art, that often outweigh the benefits that a tandem wing combination may provide.

[0115] Also described herein is a method that includes applying a differential thrust between a cambered leading wing propulsion source 18a-b and a cambered trailing wing propulsion source 20a-b of an aircraft 10 to create a moment imbalance to tilt the fuselage body 12.

[0116]

[0093] Referring to Figure 8, one exemplary application of the aircraft embodiment described above may relate to a multi-purpose tactical unmanned aerial vehicle that combines the following attributes:

[0117] Vertical takeoff and landing for airfield independence and naval operations Designed to support multiple payload options with a baseline configuration of two air-to-ground missiles (e.g., Hellfire or Brimstone) (i.e., >150 kg payload).

[0118] A > 50km range (i.e., providing long-range attack capability from naval surface ships and army brigades) Attributable assets (three airframes and control stations) with a target system price of less than $20 million · Ability to "ground handle" vehicles for movement around land-based launch areas (such as from a helicopter pad-style area into a hangar) or to maneuver vehicles on the ship's deck into a ship's hangar or storage area. Tactical / strategic transportability with long-term storage and minimal setup time In some embodiments, the aircraft 10 is configured to carry a payload below the fuselage body 12. In these embodiments, it is desirable to have sufficient ground clearance for the payload to avoid damaging it during takeoff, landing, or when the aircraft 10 tilts between a stationary configuration and a tail-sitting configuration. The payload may then be deployed in flight.

[0119]

[0095] In some embodiments, the forward undercarriage is center mounted to facilitate folding of the wings while still ensuring clearance for payload delivery and ejection.

[0120]

[0096] In some embodiments, the aft undercarriage is mounted on the inboard wing section to provide lateral stability when the aircraft is on the ground (e.g., during takeoff, landing, or when the aircraft 10 tilts between a stationary configuration and a tail-sitting configuration).

[0121]

[0097] In some embodiments, the fuselage body 12 is configured to provide a connection method for the wings.

[0122] In some embodiments, fuselage body 12 is configured to improve the aerodynamics of aircraft 10. Such features may be applicable when aircraft 10 does not carry a human pilot or passengers.

[0123] In some embodiments, the fuselage body 12 is configured to support multiple payload configurations. Such a feature may be applicable when the aircraft 10 does not carry a human pilot or passengers.

[0124] In some embodiments, the aircraft 10 may include vertical wings, for example, having small downwardly pointing vertical fins to provide a level of stability in both horizontal and vertical flight modes while also providing a level of protection against wingtip strikes in adverse landing conditions.

[0125] In some embodiments, the aircraft 10 may include a tail location for payloads that are deployed in flight (e.g., while hovering). The flight (e.g., hovering) configuration allows some sensor payload configurations to be deployed from the tail of the aircraft 10, regardless of the payload space required for payloads used in forward flight.

[0126] In some embodiments, the center of gravity of the wings 14a-b, 16a-b and fuselage body 12 may be selected based on the expected use / payload of the aircraft 10. The tandem wing and fuselage 12 configuration allows for a wider center of gravity range for the aircraft 10, which means that the aircraft 10 is more robust to changes in center of gravity for different payload combinations or when payload mass / location changes during flight (e.g., due to deployment / ejection).

[0127] In some embodiments, air is blown onto control surfaces in the propeller wake. The air may be blown by wings with elevators / flaps / ailerons. This allows for greater levels of aerodynamic control at slower airspeeds and allows for "different" stall characteristics that aid in the transition from (near) horizontal to (near) vertical flight. This provides controllability and redundancy, especially at slow airspeeds, and adds greater control flexibility (not found in traditional fixed-wing aircraft or rotorcraft that rely solely on propeller / rotor power).

[0128] In some embodiments, the wings and / or undercarriage may be configured to allow space for the wings to fold and / or rotate. This reduces the storage and ground handling footprint and helps avoid disassembly of the aircraft. For example, an aircraft may be folded with its rear wings folded forward and its front wings folded back, then rolled (assisted by the undercarriage) into a container (e.g., a 20-foot intermodal container with a "ramp" for the rear wheels within the container to seat the aircraft with the fuselage in a horizontal orientation). In some embodiments, the folding mechanism allows for the removal of a simple pin, allowing the wings to rotate approximately 90 degrees about their main spar (so that the wing chord line is approximately parallel to the aircraft "z" axis) and then folded so that the wing span is parallel to the fuselage (aircraft "x" axis). The aircraft may then be packed into the container.

[0129]

[0105] In some embodiments, the propulsion sources 18a-b, 20a-b are propellers. Optionally, the propellers are variable pitch. This facilitates more precise control of the rotational momentum from the propellers.

[0130]

[0106] In some embodiments, each propulsion source 18a-b, 20a-b is configured to provide lift for takeoff and thrust for cruise.

[0131] In some embodiments, the aircraft 10 includes a control system for remotely and / or autonomously operating the aircraft 10 by a method that includes applying differential thrust between forward and aft wing thrust sources of the aircraft to create a moment imbalance to tilt the fuselage body. Applying differential thrust can tilt the fuselage body between a stationary configuration and a tail-sitting configuration, and / or applying differential thrust can tilt the fuselage body to provide pitch control during flight.

[0132] The discussion now turns to a specific aircraft embodiment 10 that tilts from a stationary position to a tail-sitting position for immediate takeoff. As shown in FIG. 1. The aircraft 10 is seated on all four wheels to start, as shown in FIG. 3(A).

[0133] 2. A brake is applied to the rear wheel 22b to prevent forward movement (note that in areas where more space is available, the brake can be released to allow a small amount of forward movement if desired).

[0134] 3. By utilizing "forward thrust" on the two forward propellers 18a-b and "reverse thrust" on the rear propellers 20a-b, this creates a moment imbalance, causing the aircraft 10 to generate a pitching acceleration (nose up) and a corresponding pitch rate, as shown in FIG. 3(B). Note that thrust control can be achieved by variable speed and / or propeller pitch. Optionally, "reverse thrust" can be applied, for example, if the wheel brakes no longer hold the aircraft 10 stationary (reverse thrust creates both a backward force and a downward force on the rear wheels, resulting in more traction from the brakes).

[0135] 4. As shown in FIG. 3(C), once a near vertical aircraft pitch attitude is achieved, active control between the forward propellers 18a-b and the aft propellers 20a-b maintains the desired pitch attitude.

[0136] 5. All propellers 18a-b, 20a-b then provide forward thrust, causing the aircraft 10 to accelerate vertically (in a manner similar to a quadcopter), utilizing propeller thrust variation, as well as air blown over the aerodynamic control surfaces, to provide control of the aircraft 10's attitude and acceleration.

[0137] The discussion now turns to a specific aircraft embodiment 10 tilting from a tail-sitting position to a stationary position for landing. As shown in FIG. 1. The aircraft 10 arrives in a vertical orientation (in a manner similar to a "quadcopter").

[0138] 2. The aircraft 10 utilizes propeller thrust variation and air blown over aerodynamic control surfaces to provide attitude and acceleration control of the aircraft 10 to position the aircraft 10 above a landing site.

[0139] 3. The aircraft 10 develops and maintains the desired rate of descent (using the controls in step 1).

[0140] 4. As shown in Figure 6(A), when the rear wheels 22b contact the ground (by braking), the aircraft control changes mode to load the rear wheels 22b to prevent lateral movement.

[0141] 5. The aircraft 10 then utilizes differential thrust between the forward propellers 18a-b and the rear propellers 20a-b to allow the pitch attitude to "unroll," allowing the nose of the aircraft to lower at a controlled rate, as shown in Figure 6(B). When the aircraft nosewheel 22a contacts the ground surface, as shown in Figure 6(C), thrust is reduced and the aircraft 10 is considered to have "landed."

[0142]

[0110] The various aircraft embodiments 10 described thus far may provide one or more of the following:

[0143] The ability to tilt the aircraft fuselage body by applying differential thrust to the propulsion sources to achieve moment imbalance can provide superior control precision. Such control precision can result in robust takeoff / landing in adverse conditions. Adverse conditions may include environmental conditions (such as wind and gusts), launch surface conditions (such as a pitching / heave / rolling ship deck), and fault conditions (such as control surface or rotor degradation or failure). Such control precision can also provide superior pitch control during flight.

[0144] The ability to tilt the aircraft fuselage by applying differential thrust to the propulsion sources to achieve moment imbalance provides an aircraft that is easily maneuverable when stationary and thus capable of achieving (near) vertical takeoff and optionally (near) vertical landing similar to conventional tail-sitting aircraft, while eliminating the ground handling problems associated with conventional tail-sitting aircraft.

[0145] The propulsion source used to create differential thrust to achieve moment imbalance and tilt the fuselage body can also be used to provide lift to the aircraft for (near) vertical takeoff and cruise, making it unnecessary for the aircraft to have separate propulsion sources for takeoff and cruise, thus eliminating redundancy in the propulsion design.

[0146] The propulsion source used to create differential thrust to achieve moment imbalance and tilt the fuselage body means that the aircraft does not need to have tilt rotors and / or tilt wings (relative to the fuselage body), both of which are inherently complex systems.

[0147] It is noted that the aircraft embodiments described herein have a fuselage body that can tilt for the purpose of positioning the aircraft in a tail-sitting position for vertical or near-vertical takeoff. Such a tilting body mechanism facilitates the transition from a (near) vertical takeoff to cruising at extremely high altitudes from a launch pad. This provides the advantage of being able to launch an aircraft from a launch pad where space is extremely limited. The embodiments described herein should be distinguished from conventional VTOL aircraft designs in which the fuselage body can tilt during takeoff because such conventional designs can only transition from a (near) vertical takeoff to cruise to lower altitudes than those achievable by the described aircraft embodiments, and in some cases cannot transition as high from a launch pad. Such conventional VTOL aircraft designs lack versatility compared to the described embodiments.

[0148]

[0111] Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention. For example, the aircraft may have two or more fuselage bodies. In another example, there may be three or more wings. In another example, any wing may have three or more propulsion sources. In another example, while the disclosed exemplary embodiment uses a propeller as the propulsion source, the propulsion source may be other than a propeller, such as, for example, an engine. In another example, the aircraft may be configured with a tilting body and / or tilting wing mechanism. In another example, the aircraft may be manned or unmanned. In another example, the aircraft may be used in civil and / or military applications.

[0149] The presence of " / " in the figures or text of this specification is understood to mean "and / or" unless otherwise indicated, i.e., "A / B" is understood to mean "A," "B," or "A and B." Recitation of a particular numerical value or range of values ​​herein is understood to include or be a recitation of about that numerical value or range of values, for example, within + / -20%, + / -15%, + / -10%, + / -5%, + / -2.5%, + / -2%, + / -1%, + / -0.5%, or + / -0%, etc. The terms "essentially all" or "substantially" can indicate a percentage of 50%, 60%, 70%, 80%, or 90% or more, for example, 92.5%, 95%, 97.5%, 99%, or 100%.

[0150]

[0113] Reference herein to any prior publication (or information derived therefrom) or known matter is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that the prior publication (or information derived therefrom) or known matter forms part of the common general knowledge in the field of endeavor to which this specification pertains.

[0151]

[0114] Throughout this specification and the claims, unless the context otherwise requires, the words "comprise" and variations such as "comprises", "comprising" and the like will be understood to imply the inclusion of stated integers or steps or groups of integers or steps, but not the exclusion of any other integers or steps or groups of integers or steps.

Claims

1. A fuselage body and a canard having two or more propulsion sources; A rear wing having two or more thrust sources; An aircraft comprising: the front wing is located closer to a head portion of the fuselage body than the rear wing, and the rear wing is located closer to a tail portion of the fuselage body than the front wing, 1. The aircraft, wherein the aircraft is configured to apply a differential thrust between the source of thrust on the front wing and the source of thrust on the rear wing to create a moment imbalance to tilt the fuselage body.

2. 2. An aircraft according to claim 1, wherein each propulsion source and / or each wing is fixed in position relative to the fuselage body.

3. 3. The aircraft of claim 1 or 2, wherein tilting of the fuselage body of the aircraft tilts the propulsion source in conjunction with the fuselage body.

4. 4. An aircraft according to any one of claims 1 to 3, wherein the aircraft is configured to apply the differential thrust by the front wing being cambered and the rear wing being cambered.

5. 5. An aircraft according to claim 1, wherein at least one propulsion source of the front wing is located on a thrust axis that is offset from the thrust axis of the propulsion source of the rear wing.

6. 6. An aircraft according to claim 1, wherein at least one propulsion source of the rear wing is located on a thrust axis that is offset from the thrust axis of the propulsion source of the front wing.

7. the propulsion source of the aircraft a net forward thrust is exerted by the propulsion source on the canard; and / or A net reverse thrust is exerted by the thrust source on the rear wing.

7. The aircraft of claim 1, wherein the aircraft is configured to apply the differential thrust to generate the moment imbalance when

8. the propulsion source of the aircraft a net reverse thrust is exerted by the thrust source on the canard; and / or A net forward thrust is exerted by the thrust source on the rear wing.

8. The aircraft of claim 1, wherein the aircraft is configured to apply the differential thrust to generate the moment imbalance when

9. the propulsion source of the aircraft a first net forward thrust force is exerted by the propulsion source on the canard; and a second net forward thrust is exerted by the thrust source on the trailing wing; and applying the differential thrust to generate the moment imbalance when 9. The aircraft of claim 1, wherein the second net forward thrust is less than the first net forward thrust for a first differential thrust, or the second net forward thrust is greater than the first net forward thrust for a first differential thrust.

10. 10. An aircraft according to any one of claims 1 to 9, wherein the aircraft comprises at least one wheel, preferably two or more wheels.

11. 11. An aircraft according to any one of claims 1 to 10, wherein the aircraft is provided with brakes for braking the wheels.

12. 12. An aircraft as claimed in any one of claims 1 to 11, wherein at least one propulsion source is angled relative to the horizontal when the aircraft is in a stationary configuration.

13. 13. An aircraft as claimed in any preceding claim, wherein each propulsion source is configured to provide lift for takeoff and thrust for cruise.

14. 14. The aircraft of any one of claims 1 to 13, wherein the aircraft is configured to apply the differential thrust to pitch the fuselage body to provide pitch control in flight.

15. 15. The aircraft of any one of claims 1 to 14, wherein the aircraft is configured to apply the differential thrust to tilt the fuselage body between a stationary configuration and a tail-sitting configuration.

16. 16. An aircraft according to any one of claims 1 to 15, wherein the front wings are mounted closer to the underside of the fuselage body than the rear wings, and the rear wings are mounted closer to the upper surface of the fuselage body than the front wings.

17. the front wing has a cranked anhedral; and / or 17. An aircraft as claimed in any one of claims 1 to 16, wherein the rear wing has a cranked dihedral.

18. 18. An aircraft as claimed in any one of claims 1 to 17, wherein the forearms are a pair of forearms comprising a first port wing having at least one propulsion source and a first right wing having at least one propulsion source.

19. 19. An aircraft as claimed in any one of claims 1 to 18, wherein the rear wing is a pair of rear wing comprising a second left wing having at least one propulsion source and a second right wing having at least one propulsion source.

20. 20. An aircraft according to any one of claims 1 to 19, wherein the front and rear wings are foldable.

21. 21. An aircraft according to any one of claims 1 to 20, wherein the aircraft comprises two or more wheels, preferably four wheels.

22. 22. An aircraft according to any one of claims 1 to 21, wherein the aircraft is configured to take off at an inclination in the range of 65 degrees to vertical relative to the horizontal.

23. 23. An aircraft according to any one of claims 1 to 22, wherein the aircraft is configured to take off substantially vertically from a tail-sitting configuration.

24. 24. An aircraft according to any one of claims 1 to 23, wherein the aircraft is configured to take off at an inclination of between 65 degrees and 70 degrees relative to the horizontal.

25. 25. An aircraft as claimed in any one of claims 1 to 24, wherein the aircraft is configured to land substantially vertically so as to be in a tail-sitting configuration.

26. 26. An aircraft according to any one of claims 1 to 25, wherein the aircraft is configured to land at an inclination of between 65 degrees and 70 degrees relative to the horizontal.

27. 27. An aircraft according to any one of claims 1 to 26, wherein the aircraft comprises a control system for operating the aircraft remotely and / or autonomously.

28. 28. An aircraft according to any one of claims 1 to 27, wherein the aircraft is configured to carry a payload of 150 kg or more.

29. 1. A method comprising: applying a differential thrust between forward and aft wing thrust sources of an aircraft to create a moment imbalance to tilt a fuselage body.

30. 30. The method of claim 29, wherein each propulsion source and / or each wing of the aircraft is fixed in position relative to the fuselage body.

31. 31. A method according to claim 29 or 30, wherein tilting of the fuselage body of the aircraft tilts the forward and aft propulsion sources in conjunction with the fuselage body.

32. 32. A method according to any one of claims 29 to 31, comprising applying the differential thrust by means of a cambered front wing and a cambered rear wing.

33. 33. The method of any one of claims 29 to 32, the method further comprising applying the differential thrust to tilt the fuselage body between a stationary configuration and a tail-sitting configuration.

34. 34. The method of any one of claims 29 to 33, the method further comprising applying the differential thrust to pitch the fuselage body to provide pitch control in flight.

35. A fuselage body and a cambered fore wing having two or more propulsion sources; a cambered rear wing having two or more thrust sources; An aircraft comprising: the front wing is located closer to a head portion of the fuselage body than the rear wing, and the rear wing is located closer to a tail portion of the fuselage body than the front wing, 1. The aircraft, wherein the aircraft is configured to apply a differential thrust between the propulsion source of the front wing and the propulsion source of the rear wing to create a moment imbalance to tilt the fuselage body.

36. 36. The aircraft of claim 35, wherein the cambered front wing provides at least one propulsion source for the front wing with a lever arm separation from the propulsion source for the rear wing to facilitate the moment imbalance to tilt the fuselage body.

37. 37. The aircraft of claim 35 or 36, wherein the cambered rear wing provides at least one propulsion source for the rear wing with a lever arm separation from the propulsion source for the front wing to facilitate the moment imbalance to tilt the fuselage body.

38. 1. A method comprising: applying a differential thrust between a cambered front wing propulsion source and a cambered rear wing propulsion source of an aircraft to create a moment imbalance to tilt a fuselage body.

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