Vertical take-off and landing aircraft, method and system for controlling vertical take-off and landing aircraft

Abstract

To provide a different hybrid aircraft by maximizing the revenue load that the hybrid aircraft can transport.SOLUTION: The present invention relates to a vertical take-off and landing (VTOL) aircraft, a method of controlling a VTOL aircraft, and a control system for controlling a VTOL aircraft. The aircraft comprises a fuselage having wings extending along transverse axes and attached to a fuselage extending between longitudinal axes of the aircraft, and a tail unit or a front tail unit. An array of electric rotors is fixedly mounted to the airframe. The front and rear internal combustion engines are pivotally mounted to the fuselage, and the front and rear rotors are displaceable between a lift position oriented to provide vertical lift to the aircraft for vertical flight and a propulsion position in which the front and rear rotors are oriented to provide forward thrust to the aircraft for horizontal flight. The front and rear rotors provide most or all of the vertical lift for the aircraft during vertical flight.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to airborne vehicles or aircraft, particularly vertical take-off and landing aircraft, and to methods and systems for controlling such aircraft.

[0002] Background of the Invention

[0003] Aircraft or airborne vehicles have been used for decades to transport cargo payloads weighing hundreds of kilograms by air from one location to another, for example, over distances of hundreds, if not thousands, of kilometers.

[0004] A conventional fixed-wing aircraft typically includes a fuselage terminated at the rear by a tail and a pair of fixed wings positioned to the sides of the fuselage and extending transversely to the aircraft's longitudinal axis. Instead of a tail configuration, some fixed-wing aircraft have a canard configuration, in which a canard is provided adjacent to the front of the aircraft fuselage. A suitable propulsion assembly, including one or more engines, particularly internal combustion engines, typically has an airfoil-shaped wing, provides forward thrust to the aircraft so that the aircraft has adequate lift after reaching a certain ground speed. While conventional fixed-wing aircraft of the type described above are a simple and reliable means of lifting large and heavy payloads using relatively low-cost fuel, they require relatively long runways to reach the speeds necessary to achieve the desired lift to launch these aircraft into the air. This makes them difficult to deploy in densely populated areas. Furthermore, payloads are difficult to deploy on conventional fixed-wing aircraft due to their forward speed during use.

[0005] To this end, vertical take-off and landing (VTOL) vehicles or aircraft conveniently eliminate the requirement for a runway to become an aircraft, and can lift and deploy payloads to a predetermined location in a relatively precise manner with little or no forward speed. VTOL aircraft are generally manned or unmanned and are capable of both vertical and horizontal flight. Notably, these aircraft take off and land vertically, and once in flight, are capable of horizontal flight.

[0006] A helicopter is an exemplary embodiment of a manned VTOL aircraft having a fuselage coupled to a suitable propulsion assembly, which includes one or more internal combustion engines coupled to one or more rotors that provide lift and thrust for the helicopter. Due to the helicopter's hovering capabilities, helicopters can lift payloads of moderate size and / or weight and deploy them at extreme locations with little or no forward speed. However, helicopters generally lack redundancy against mechanical failure, consume a lot of power in flight, have a short range due to their low speed and high power requirements, and have complex mechanics that are susceptible to failure.

[0007] Unmanned aerial vehicles (UAVs) with VTOL capabilities, such as multirotor aircraft, typically include an array of electric motors coupled to a fuselage, enabling the multirotor aircraft to lift a payload and deploy the payload to extreme positions with little or no forward speed due to the multirotor's hovering capabilities. The electric motors are typically powered by rechargeable battery banks, and therefore flight times are limited due to the storage capacity of current battery technology. Furthermore, multirotor aircraft typically have high power consumption during flight and fly at relatively low flight speeds, which, combined with the limited flight time, results in multirotor aircraft having a relatively low range.

[0008] Hybrid aircraft including both internal combustion and electrically driven rotors are known. For example, U.S. Patent No. 2019 / 263519 A1 discloses a hybrid aircraft or drone including both internal combustion and electrically driven rotors, where the internal combustion engine is configured in addition to the electric rotor to provide vertical flight for the hybrid aircraft, increasing endurance, or the amount of time the aircraft can remain airborne, which has traditionally been hindered by the battery storage capacity of the accumulator powering the electric rotor. The hybrid aircraft disclosed in U.S. Patent No. 2019 / 263519 A1 does not attempt to maximize the payload the hybrid aircraft can carry, and thus transportation, which is important from at least a commercial and resource-saving perspective.

[0009] EP 3 116 781 A1 discloses a hybrid unmanned aerial multi-rotor aircraft having both an internal combustion engine and an electrically driven rotor, and an improved DC power system. Like U.S. Patent No. 2019 / 263519, the EP 3 116 781 A1 disclosure utilizes an internal combustion engine to address durability issues associated with electrically driven rotors. However, the EP 3 116 781 A1 disclosure couples an alternator to a fuel-consuming internal combustion engine to power a DC power system, which drives the electric rotor.

[0010] Other hybrid airborne vehicles or aircraft, such as those disclosed in U.S. Patent No. 2017 / 300066 A1 and WO 2019 / 190263, disclose various hybrid arrangements that utilize internal combustion and electrically driven rotors to address the stability and durability issues of aircraft with only electrically driven rotors.

[0011] One drawback the inventors have identified with conventional hybrid aircraft of the type described herein is that they do not address the problem of maximizing the payload capacity of the aircraft. A primary objective of the invention disclosed herein is to provide a different hybrid aircraft by maximizing the payload that the hybrid aircraft can transport.

[0012] For the sake of simplicity, in the context of this document, the terms "aircraft," "aerial vehicle," and "drone" will be understood to mean the same thing. Summary of the Invention

[0013] According to one aspect of the present invention, there is provided a vertical take-off and landing (VTOL) aircraft comprising an airframe having at least one or at least one pair of wings extending along a transverse axis, the airframe comprising: an airframe, the wings being operatively attached to a fuselage, the fuselage having forward and aft ends extending between a longitudinal axis of the aircraft, and a tail located adjacent the aft end of the fuselage or a canard located adjacent the forward end of the fuselage; an array of electric rotors operatively mounted to the airframe to provide vertical and / or lift stability to the aircraft, the electric rotors being fixedly mounted to the airframe and driven by one or more suitable electric motors; a front rotor pivotally mounted on the nose of the fuselage, the front rotor being displaceable about an axis parallel to the transverse axis between a lift position oriented to provide vertical lift to the aircraft for vertical flight and a thrust position oriented to provide forward thrust to the aircraft for horizontal flight; a rear rotor pivotally mounted on the aft end of the fuselage, the rear rotor being displaceable about an axis parallel to the transverse axis between a lift position in which the rear rotor is oriented to provide vertical lift to the aircraft for vertical flight and a thrust position in which the rear rotor is oriented to provide forward thrust to the aircraft for horizontal flight; wherein one or both of the front and rear rotors are driven by one or more suitable internal combustion engines, and the front and rear rotors provide most or all of the vertical lift to the aircraft during vertical flight when the front and rear rotors are in a lifting position.

[0014] The forward rotor may be pivotally mounted between the fuselage and the canard. The aft rotor may be pivotally mounted between the fuselage and the tail. Thus, in the canard configuration, the forward rotor is free to pivot in the zone between the canard and the nose of the fuselage. Similarly, in the tail configuration, the aft rotor is free to pivot in the region between the tail and the aft end of the fuselage.

[0015] The aircraft disclosed herein may be an unmanned aerial vehicle.

[0016] The forward and aft rotors may be configured to provide primary vertical lift to the aircraft, and the electric rotor may be configured to provide primary stability to the aircraft, at least during vertical flight. The electric rotor may also be configured to provide secondary vertical lift to the aircraft. However, the second vertical lift may be negligible. In other words, most or all of the vertical lift may be provided by the forward and aft rotors, with the electric rotor providing stability. It will be appreciated that the electric rotor may also provide stability during hover maneuvers.

[0017] The array of electric rotors may be mounted to the airframe in a spaced apart configuration and disposed within a third plane. The electric rotors are operatively coplanar and lie in a first plane, and the forward and aft rotors lie in second and third planes that are substantially coplanar and / or parallel to the first plane when the forward and aft rotors are operated to the lifting position in use. In one exemplary embodiment, the second and third planes may sandwich the first plane. In one exemplary embodiment, the first, second, and third planes may be parallel and spaced apart at different heights along the vertical axis.

[0018] In one exemplary embodiment, the front and rear rotors may be configured to rotate in opposite directions, such that their resultant torque is zero about the vertical axis, thereby enabling yaw stabilization and control during hover.

[0019] The aircraft may include a forward IC engine drivingly coupled to the forward rotor and an aft IC engine drivingly coupled to the aft rotor, the forward and aft engines, as well as the forward and aft rotors, being located adjacent opposite spaced-apart leading and aft ends of the fuselage. The internal combustion engine may be configured to burn a high-energy-density fuel. In an exemplary embodiment, the engine may be a fuel-burning internal combustion engine. The fuel may be gasoline, and thus the engine may be a gasoline-powered internal combustion engine. However, the fuel may be any combustible fuel configured to power an internal combustion engine. The forward and aft rotors may be longitudinally spaced apart.

[0020] In other exemplary embodiments, the aircraft may include one or more IC engines drivingly coupled to both the front and rear rotors.

[0021] The front and rear engines may be positioned equidistant from the center of gravity of the aircraft along the longitudinal axis. Furthermore, the thrust of the front and rear rotors that provide the lift described herein may be matched. In this manner, matched thrust from the front and rear rotors positioned equidistant from the center of gravity of the aircraft does not impart pitch or roll forces to the aircraft.

[0022] Each of the front and rear rotors may be at least two times more powerful than one of the electric rotors. In many cases, the front and rear rotors may be many times more powerful than the electric rotor.

[0023] It should be noted that the majority (75-100%) of the thrust for vertical flight may be provided by the front and rear rotors. Having the front and rear rotors powered by an internal combustion engine for vertical flight is advantageous due to the high power-to-weight ratio (kW.hrs / kg) of the internal combustion engine and its fuel. The electric rotor may be coupled to one or more electric cells or batteries that provide approximately 5-15 minutes of operation for the electric rotor array. In one exemplary embodiment, that is approximately 5 minutes, resulting in a 5 minute vertical flight time.

[0024] In a different definition, the electric rotor is powered by a power source (e.g., a battery as described herein) configured to power the electric rotor for a time period shorter than the time the forward and aft rotors can be powered by one or more internal combustion engines. The total operating time of the electric rotors may be a small fraction of the aircraft's flight time for a particular mission, and the forward and aft rotors are powered for the duration of the mission. Because the electric rotor primarily provides stability, it does not need to provide battery power to operate for the entire mission, but only for vertical flight. This therefore reduces the size of the battery required to power the electric rotor, thereby maximizing the payload the aircraft can transport when in use.

[0025] An array of electric rotors may comprise multiple electric rotors attached to one or more of the fuselage, wings, winglets, fins, tails or canards, and one or more booms on the airframe. The electric rotors may be equidistant and / or attached to the airframe.

[0026] The size or power of the electric motor may be inversely proportional to its distance from the center of gravity of the aircraft. In this regard, the further an electric motor is from the center of gravity of the aircraft, the smaller and / or weaker it will be than if it were closer to the center of gravity of the aircraft. In this regard, the forward and aft rotors of the aircraft may be closer to the center of gravity of the aircraft than the electric rotor. The array of electric rotors may include substantially similar electric rotors.

[0027] In one exemplary embodiment, the array of electric rotors may include four electric rotors positioned adjacent the corners of an imaginary quadrilateral centered on the airframe. The quadrilateral may be a square such that the electric rotors are equidistantly spaced apart to balance each other.

[0028] Note that the aircraft may include four three-phase AC electric motors, each drivingly connected to a respective electric rotor. DC battery power may be converted to AC by an ESC (Electronic Speed ​​Control). In some exemplary embodiments, the aircraft may include more than four motors and / or rotors. For example, the aircraft may include six or eight electric motors, each drivingly connected to six or eight rotors. The electric motors may be powered by an energy storage device, such as a rechargeable battery, e.g., a lithium-ion battery. Lithium-ion batteries and brushless motors have the advantage of much higher instantaneous energy density (W / kg) than fuel-burning IC motors. However, they have a very low total energy density (kW.hrs / kg). As a result, due to their relatively low energy density, larger batteries are required for longer use, and the weight of these larger batteries reduces the aircraft's payload capacity. In this regard, using high-energy-density fuel and internal combustion engine-driven rotors for as many flights as possible advantageously reduces the requirement for larger and heavier batteries.

[0029] For simplicity, the term "rotor" as used herein may be understood to mean, in the case of an electric rotor, the propeller blades driven by a suitable AC motor powered by a battery, and, in the case of the front and rear rotors, by a suitable IC engine that burns fuel. However, those skilled in the art will understand that, when the context is clear, the term "rotor" may be understood to include the propeller blades and the motor and / or engine drivingly connected to the propeller blades.

[0030] Electric motors have sufficient torque and response time to precisely and quickly change revolutions per minute (RPM) to maintain stability during vertical flight. In this way, the aircraft can maintain the rapid and continuous corrections necessary for stable vertical flight. This differs from internal combustion engines, which have slower response times to throttle changes and are unable to maintain stability in multi-rotor configurations. Therefore, the configuration described herein maximizes the thrust and lift benefits of the IC rotors and engines, as well as the finer control profile of the electric rotors and motors, so that the electric rotors are not overwhelmed by the relatively heavy IC rotors during lift, since the IC rotors provide the majority of the thrust. Similarly, the slower response of the IC rotors in stabilizing the aircraft during vertical flight is addressed by the more precisely controlled electric motors. In this way, the internal combustion (IC) leading and trailing rotors lift the aircraft, while the much smaller electric motors balance it. This means that the electric motors can be very small and very light, using smaller power cells (e.g., their lithium-ion batteries can be sized just right for short hovering periods, e.g., about two minutes). As a result, when the aircraft transitions to forward flight as a conventional fixed-wing aircraft, it has a very small weight penalty in the form of electric hover motors. This capability allows it to carry higher payloads over longer distances for longer periods of time (longer endurance).

[0031] The aircraft receiving and / or intercepting aircraft control signals including lift commands and / or stability commands for the array of electric rotors and / or the front and rear rotors to control lift and / or stability, respectively, of the aircraft during vertical flight; using lift commands to control the front rotor and the rear rotor to provide most or all of the vertical lift to the aircraft during vertical flight; A suitable processor may be provided that is configured to use the stability commands to control the array of electric rotors to provide stability to the aircraft during vertical flight.

[0032] The processor may be an on-board processor of the aircraft. The processor may be configured to intercept control signals from a flight control module of the aircraft operable to control at least vertical flight.

[0033] As referred to herein, the term "vertical flight" may be understood to include vertical flight (i.e., radially outward from the center of the Earth), as well as hovering and hover maneuvers (i.e., remaining relatively spatially stationary in the air). In some exemplary embodiments, the array of electric rotors is engaged only during vertical flight hovering and / or hover maneuvers to provide stability to the vehicle.

[0034] The processor Processing the received / intercepted aircraft control signals to determine lift and / or stability commands; The lift commands and / or stability commands can be selected and configured for use in controlling the electric rotor and / or the array of front and rear rotors.

[0035] In an exemplary embodiment of the invention, the processor is configured to receive information from a sensor selected from the group including a pitot tube, a tachometer, an accelerometer, a gyroscope, a magnetometer, a global positioning system (GPS), a thermocouple, and an altimeter.

[0036] The processor may be configured to generate appropriate control signals, including lift and / or stability commands. The control signals may control the array of electric rotors and / or the front and rear rotors. To this end, the processor may be configured to translate the lift commands into commands configured to control the throttle of the IC engines to provide the desired lift required, since aircraft control signals for controlling vertical flight may be directed solely to the electric motors.

[0037] In an exemplary embodiment, the forward and aft rotors may be mounted to the fuselage via vector control mountings that facilitate vector control of the forward and aft rotors between the lift and thrust positions. The vector control mountings may be identical, one for swiveling / tilting upward and one for swiveling / tilting downward. The upper swiveling / tilting mounting may be operably coupled to the fuselage and the forward rotor to swivel the forward rotor upward in use. The lower swiveling / tilting mounting may be operably coupled to the fuselage and the aft rotor to swivel the aft rotor downward in use. Each control mounting may include a suitable rack and pinion mounting configured to be actuated by a suitable actuator, such as a servo motor, to precisely displace the forward and aft rotors in use between the lift and thrust positions. The control mountings may facilitate locking the forward and aft rotors in desired positions, including between and including the lift and thrust positions.

[0038] A vector control mounting operatively connecting the forward rotor to the fuselage can be configured to pivot the forward rotor upward from a thrust position to a lift position. Conversely, a vector control mounting operatively connecting the aft rotor to the fuselage can be configured to pivot the aft rotor downward from a thrust position to a lift position. Thus, when the aircraft is in vertical flight, the forward rotor is positioned in a second plane above the wing and the aft rotor is positioned in a third plane below the wing.

[0039] The rear rotor may be in a pusher configuration for horizontal flight and may be vectored downward during vertical flight. The rear rotor may pass below the tail or a plane defined thereby during transition to a lifting position.

[0040] For clarity, the transverse axis may be the pitch axis of the aircraft or an axis parallel to the pitch axis. Similarly, the longitudinal axis may be the roll axis. The longitudinal axis as described herein may be parallel to the plane in which the electric rotors rotate, and the front and rear rotors rotate when in a lifting position, and the longitudinal axis may be the yaw axis of the aircraft or an axis parallel to the yaw axis of the aircraft.

[0041] In one exemplary embodiment, the front and rear rotors may be slightly offset from the vertical axis in a counterclockwise direction about the longitudinal axis as viewed from the front of the aircraft. In particular, the front and rear rotors may be slightly canted from the vertical axis by approximately 1.8 degrees in a counterclockwise direction about the longitudinal axis as viewed from the front of the aircraft. This configuration counteracts the effects of yaw caused by asymmetric airflow over the aircraft due to the proximity of the IC rotors and / or their associated IC motors to the tail.

[0042] According to another aspect of the present invention, there is provided a method of controlling a vertical take-off and landing (VTOL) aircraft, the aircraft comprising: an airframe having at least one or at least one pair of wings extending along a transverse axis, the airframe being operably attached to a fuselage having forward and aft ends extending between a longitudinal axis of the aircraft, and a tail located adjacent the aft end of the fuselage or a canard located adjacent the forward end of the fuselage; an array of electric rotors operably mounted on the airframe to provide vertical stability and / or lift to the aircraft, the electric rotors being fixedly mounted on the airframe and driven by one or more suitable electric motors; and a nose rotor pivotally mounted to a leading edge of the fuselage. a forward rotor, the forward rotor being displaceable about an axis parallel to the lateral axis between a lift position oriented to provide vertical lift to the aircraft for vertical flight and a thrust position oriented to provide forward thrust to the aircraft for horizontal flight; and a rear rotor, pivotally mounted to the aft end of the fuselage, the rear rotor being displaceable about an axis parallel to the lateral axis between a lift position oriented to provide vertical lift to the aircraft for vertical flight and a thrust position oriented to provide forward thrust to the aircraft for horizontal flight, one or both of the forward and rear rotors being driven by one or more suitable internal combustion engines, the method comprising: controlling the front rotor and the rear rotor to be displaceable between a thrust position for horizontal flight and a lift position for vertical flight; controlling the forward and aft rotors to place the forward and aft rotors in lifting positions to provide most or all of the vertical lift for the aircraft in vertical flight; Includes.

[0043] This method is receiving and / or intercepting aircraft control signals including lift commands and / or stability commands for controlling lift and / or stability of the aircraft during vertical flight; controlling the front rotor and the front rotor using lift commands to provide most or all of the vertical lift to the aircraft during vertical flight and controlling the array of electric rotors using stability commands to provide stability to the aircraft during vertical flight; Includes.

[0044] Furthermore, this method processing the received / intercepted aircraft control signals to determine lift and / or stability commands; selecting lift commands and / or stability commands and using them to control the electric rotor and / or the array of front and rear rotors; may include:

[0045] The method may include intercepting aircraft control signals from a suitable flight control system intended to control only the electric motors and / or rotors, and to this end, translating lift commands into a format for controlling the front and rear rotors.

[0046] The array of electric rotors may be mounted to the airframe in a spaced apart configuration, the electric rotors being operatively coplanar and disposed in a first plane, the method including displacing the forward and aft rotors to a lift position for vertical flight, wherein the forward and aft rotors are disposed in second and third planes, respectively, that are substantially coplanar with and / or parallel to the first plane when the forward and aft rotors are operated to the lift position.

[0047] According to another aspect of the present invention, there is provided a control system for controlling a vertical take-off and landing (VTOL) aircraft, the control system comprising: an airframe having at least one or at least one pair of wings extending along a transverse axis, the wings operably attached to a fuselage having leading and trailing ends extending between a longitudinal axis of the aircraft, and a tail located adjacent the aft end of the fuselage or a canard located adjacent the forward end of the fuselage; an array of electric rotors operably mounted on the airframe to provide vertical lift stabilization and / or lift to the aircraft, the electric rotors fixedly mounted on the airframe and driven by one or more suitable electric motors; and a forward rotor pivotally mounted at a leading edge of the airframe. a rotor displaceable about an axis parallel to the lateral direction between a lift position in which the forward rotor is oriented to provide vertical lift to the aircraft for vertical flight and a thrust position in which the forward rotor is oriented to provide forward thrust to the aircraft for horizontal flight; and a rear rotor pivotally mounted to the aft end of the fuselage, the aft rotor displaceable about an axis parallel to the lateral axis between a lift position in which the aft rotor is oriented to provide vertical lift to the aircraft for vertical flight and a thrust position in which the aft rotor is oriented to provide forward thrust to the aircraft for horizontal flight, one or both of the forward and aft rotors being driven by one or more suitable internal combustion engines, the system comprising: a memory device; a processor coupled to the memory device, the processor configured to control the forward and aft rotors to be displaceable between a thrust position for horizontal flight and a lift position for vertical flight, and to control the forward and aft rotors to be in a lift position to provide most or all of the vertical lift to the aircraft during vertical flight; Equipped with.

[0048] This processor is receiving and / or intercepting aircraft control signals including lift and / or stability commands that control the lift and / or stability of the aircraft during vertical flight; controlling the forward rotor and the forward rotor using lift commands that provide most or all of the vertical lift to the aircraft during vertical flight; The array of electric rotors may be configured to be controlled using stability commands that provide stability to the aircraft during vertical flight.

[0049] This processor is Processing the received / intercepted aircraft control signals to determine lift and / or stability commands; The lift commands and / or stability commands may be selected and configured to be used to control the electric rotor and / or the array of front and rear rotors.

[0050] The processor may be further configured to convert the lift commands into a format that controls the forward and aft rotors. The array of electric rotors may be mounted to the airframe in a spaced apart configuration, the electric rotors being operatively coplanar and positioned in a first plane, and the processor configured to displace the forward and aft rotors to a lift position for vertical flight, where the forward and aft rotors are positioned in a second and a third plane, respectively, that are substantially coplanar with and / or parallel to the first plane when the forward and aft rotors are operated to the lift position.

[0051] According to yet another exemplary embodiment of the present invention, there is provided a non-transitory computer-readable storage medium storing non-transitory computer-executable instructions which, when executed remotely by a suitable processor in communication with or onboard a vertical take-off and landing (VTOL) aircraft, cause at least one processor to perform the steps of any of the methods described above, wherein the aircraft comprises an airframe having at least one or at least one pair of wings extending along a lateral axis, the wings operably attached to a fuselage, the fuselage having leading and trailing ends extending between a longitudinal axis of the aircraft and a tail unit located adjacent the trailing end of the fuselage or a canard unit located adjacent the leading end of the fuselage; and an array of electric rotors operably attached to the airframe to provide vertical lift and / or stability to the aircraft, the electric rotors being fixedly attached to the airframe and driven by one or more suitable electric motors. the forward rotor is pivotally mounted on the nose of the fuselage, the forward rotor being displaceable about an axis parallel to the lateral axis between a lift position and a thrust position, wherein in the lift position the forward rotor is oriented to provide vertical lift to the aircraft for vertical flight and in the thrust position the forward rotor is oriented to provide forward thrust to the aircraft for horizontal flight; and the aft rotor is pivotally mounted on the distal end of the fuselage, the aft rotor being displaceable about an axis parallel to the lateral direction between a lift position and a thrust position, wherein in the lift position the aft rotor is oriented to provide vertical lift to the aircraft for vertical flight and in the thrust position the aft rotor is oriented to provide forward thrust to the aircraft for horizontal flight, one or both of the forward and aft rotors being driven by one or more suitable internal combustion engines.

[0052] According to yet another exemplary embodiment of the present invention, there is provided a method for controlling a vertical take-off and landing (VTOL) aircraft, the method comprising: receiving and / or intercepting aircraft control signals including lift and / or stability commands for controlling lift and / or stability of the aircraft during vertical flight; processing the received / intercepted aircraft control signals to determine lift and / or stability commands; filtering the lift command and / or stability command; converting the lift command into a format to control one or more internal combustion (IC) rotors driven by one or more internal combustion engines; generating appropriate lift command signals including the translated lift commands to control one or more IC rotors to provide most or all of the vertical lift to the aircraft during vertical flight; generating appropriate stability command signals including stability commands selected to control the array of electric rotors to provide stability to the aircraft during vertical flight; Includes.

[0053] According to another aspect of the present invention, there is provided a system for controlling a vertical take-off and landing (VTOL) aircraft, the system comprising: A storage device; at least one processor; the processor comprising: receiving and / or intercepting aircraft control signals including lift and / or stability commands for controlling the lift and / or stability of said aircraft during vertical flight; Processing the received / intercepted aircraft control signals to determine lift and / or stability commands; Selecting lift commands and / or stability commands; converting the lift command into a format that controls one or more internal combustion (IC) rotors driven by one or more internal combustion engines; generating appropriate lift command signals including the converted lift commands to control the one or more IC rotors to provide most or all of the vertical lift to the aircraft during vertical flight; Appropriate stability command signals, including selected stability commands, are configured to control the array of electric rotors to provide stability to the aircraft during vertical flight.

[0054] According to another aspect of the present invention, there is provided a non-transitory computer-readable storage medium storing non-transitory computer-executable instructions which, when executed by a suitable processor, cause the processor to: receiving and / or intercepting aircraft control signals including lift and / or stability commands for controlling the lift and / or stability of said aircraft during vertical flight; Processing the received / intercepted aircraft control signals to determine lift commands; Selecting lift commands and / or stability commands; converting the lift command into a format that controls one or more internal combustion (IC) rotors driven by one or more internal combustion engines; generating appropriate lift command signals including the converted lift commands to control one or more IC rotors; The method causes the aircraft to provide most or all of its vertical lift during vertical flight, and generates appropriate stability command signals, including selected stability commands, to control an array of electric rotors to provide stability to the aircraft during vertical flight.

[0055] According to another aspect of the present invention, there is provided an aircraft comprising a system as described herein operatively connected thereto.

[0056] According to yet another aspect of the present invention, there is provided a method of operating a hybrid aircraft having an electric rotor and an internal combustion rotor, wherein the electric rotor is driven by an electric motor and the internal combustion rotor is driven by an internal combustion engine, the method comprising: using both an internal combustion rotor and an electric rotor for vertical flight; using an internal combustion rotor for horizontal flight; Includes.

[0057] It will be understood that a description herein of one embodiment of the invention applies to other embodiments of the invention. [Brief explanation of the drawings]

[0058] [Figure 1] FIG. 1 illustrates a front perspective view of a VTOL air vehicle having front and rear rotors configured for vertical flight in accordance with an exemplary embodiment of the present invention. [Figure 2] FIG. 2 illustrates a perspective rear view of a VTOL air vehicle having front and rear rotors configured for vertical flight in accordance with an exemplary embodiment of the present invention. [Figure 3] FIG. 3 shows a side view of a VTOL aircraft according to an exemplary embodiment of the present invention having front and rear rotors configured for vertical flight, with the opposite side view having a similar profile. [Figure 4] FIG. 4 illustrates a rear view of a VTOL air vehicle having front and rear rotors configured for vertical flight in accordance with an exemplary embodiment of the present invention. [Figure 5] FIG. 5 illustrates a front view of a VTOL air vehicle having front and rear rotors configured for vertical flight in accordance with an exemplary embodiment of the present invention. [Figure 6] FIG. 6 illustrates a top or plan view of a VTOL aircraft having front and rear rotors configured for vertical flight in accordance with an exemplary embodiment of the present invention. [Figure 7] FIG. 7 illustrates a bottom view of a VTOL air vehicle having front and rear rotors configured for vertical flight in accordance with an exemplary embodiment of the present invention. [Figure 8] FIG. 8 illustrates a front perspective view of a VTOL air vehicle having front and rear rotors configured for horizontal flight in accordance with an exemplary embodiment of the present invention. [Figure 9] FIG. 9 illustrates a rear perspective view of a VTOL air vehicle having front and rear rotors configured for horizontal flight in accordance with an exemplary embodiment of the present invention. [Figure 10] FIG. 10 illustrates a side view of a VTOL aircraft in accordance with an exemplary embodiment of the present invention with front and rear rotors configured for horizontal flight, with the opposite side view having a similar profile. [Figure 11] FIG. 11 illustrates a rear view of a VTOL air vehicle having front and rear rotors configured for horizontal flight in accordance with an exemplary embodiment of the present invention. [Figure 12] FIG. 12 illustrates a front view of a VTOL air vehicle having front and rear rotors configured for horizontal flight in accordance with an exemplary embodiment of the present invention. [Figure 13] FIG. 13 illustrates a perspective view of a vector control mount in accordance with an exemplary embodiment of the present invention having forward and aft rotors configured for horizontal flight. [Figure 14] FIG. 14 illustrates a block diagram of a flight control system in accordance with an exemplary embodiment of the present invention. [Figure 15] FIG. 15 illustrates a high-level block flowchart of a method for controlling a VTOL aircraft in accordance with an exemplary embodiment of the present invention. [Figure 16] FIG. 16 depicts another high-level block flowchart of a method for controlling a VTOL aircraft in accordance with an exemplary embodiment of the present invention. [Figure 17] FIG. 17 illustrates a front perspective view of another VTOL air vehicle having front and rear rotors configured for vertical flight in accordance with an illustrative embodiment of the present invention. [Figure 18] FIG. 18 illustrates a front perspective view of another VTOL air vehicle having front and rear rotors configured for vertical flight in accordance with an illustrative embodiment of the present invention. [Figure 19] FIG. 19 illustrates a front perspective view of yet another VTOL air vehicle in accordance with an illustrative embodiment of the present invention having front and rear rotors configured for vertical flight. [Figure 20] FIG. 20 shows a diagrammatic representation of a machine in the exemplary form of a computer system on which a set of instructions are executable to cause the machine to perform any one or more of the methodologies described herein. Detailed Description of the Drawings

[0059] The following description of the present invention is provided as a teaching of the enabling knowledge of the present invention. Those skilled in the art will recognize that many changes can be made to the described embodiments while still achieving the beneficial results of the present invention. It will also be apparent that some of the desired advantages of the present invention can be achieved by selecting some of the features of the present invention without utilizing other features. Accordingly, those skilled in the art will recognize that modifications and adaptations to the present invention are possible and may even be desirable in certain circumstances. Accordingly, the following description is provided as an illustration of the principles of the present invention, and not in limitation thereof.

[0060] It will be understood that the phrases "for example," "such as," and variations thereof describe non-limiting embodiments of the subject matter disclosed herein. As used herein, the phrase "one exemplary embodiment," "another exemplary embodiment," "some exemplary embodiments," or variations thereof means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the presently disclosed subject matter. Thus, use of the phrases "one exemplary embodiment," "another exemplary embodiment," "some exemplary embodiments," or variations thereof do not necessarily refer to the same embodiment.

[0061] Unless otherwise stated, some features of the subject matter described in this specification, which are for clarity described in the context of separate embodiments, may also be provided in combination in a single embodiment, provided they fall within the scope of any one of the appended claims. Similarly, various features of the subject matter disclosed in this specification that are described in the context of a single embodiment may also be provided separately or in any suitable subcombination, provided they fall within the scope of any one of the appended claims.

[0062] The headings used herein are for organizational purposes only and are not intended to be used to limit the scope of the description or the claims. For brevity, the word "may" is used in its permissive sense (i.e., meaning "having the potential to") rather than its mandatory sense (i.e., meaning "must").

[0063] The words "include," "including," and "includes," and "comprises," "comprising," and "comprises" mean, but are not limited to, "including" and "comprising." Additionally, as used herein, the term "coupled" can refer to two or more components joined together, whether the joining is permanent (e.g., "welded") or temporary (e.g., "bolted," "screwed"), direct or indirect (i.e., "through an intermediary"), mechanical, chemical, optical, or electrical.

[0064] Furthermore, as used herein, "horizontal" flight refers to flight proceeding in a direction substantially parallel to the ground (i.e., sea level), and "vertical" flight refers to flight proceeding substantially radially outward from the center of the Earth. It should be understood that a trajectory can include components of both "horizontal" and "vertical" flight vectors. Furthermore, the terms "hovering" or "hovering" can be understood to mean remaining at substantially the same vertical and horizontal spatial position. "Vertical" flight in the context of the present disclosure is understood to include "hovering" and "hovering," as understood from the disclosure herein.

[0065] 1-7, a VTOL aircraft according to an exemplary embodiment of the present invention is generally designated by the reference numeral 10. While VTOL aircraft 10 may typically be an unmanned aerial vehicle, it will be understood that nothing in this disclosure precludes extending the teachings of the knowledge contained herein to manned aerial vehicles. VTOL aircraft 10 is advantageously capable of vertical flight (including vertical takeoff and landing, stable and stable hovering) and horizontal flight (including horizontal fixed-wing flight) for carrying and transporting payloads over long distances. For example, a payload of approximately 50 kg on a mission from an origin to a delivery destination approximately 50 km away and back to the origin (i.e., a 100 km return trip or mission).

[0066] The aircraft 10 includes a number of components (electrical, electronic, mechanical, pneumatic, and / or hydraulic), circuits, actuators, mechanical links, etc., which for ease of explanation are not shown or discussed in greater detail, but would be apparent to one skilled in the art of the invention.

[0067] The aircraft 10 comprises an airframe 12 including a fuselage 14 extending along a longitudinal axis A (see FIGS. 6 and 7), elongated fixed wings 16 extending along a transverse axis B (see FIGS. 6 and 7) attached to the center of the fuselage 14, and a tail 18. The airframe 12 is fabricated largely from composite lightweight materials to minimize weight. For example, the airframe 12 may be constructed from fiberglass and carbon fiber with a high-density polystyrene core.

[0068] The wing 16 has a left wing section 16.1 and a right wing section 16.2 that are equal in length. The wing 16 generally has a high aspect ratio and, as described herein, is in the form of an airfoil to facilitate lift, and therefore flight, of the aircraft 10. Thus, the wing 16 may be in the shape of a conventional aircraft wing, having upper and lower surfaces and leading and trailing edges that, in use, facilitate lift as air passes over the wing.

[0069] It should be noted that while a single wing 16 is illustrated, two or more components may be connected together to form the wing 16. In one exemplary embodiment, the left and right wing sections 16.1, 16.2 are each attached to the fuselage 14 independently of one another. Furthermore, although not illustrated, it will be understood that in some exemplary embodiments of the invention described herein, the wing 16 may include suitable controllable ailerons disposed on the left and right wing sections 16.1, 16.2, particularly adjacent trailing edges of the wing 16, for use in a conventional manner.

[0070] The fuselage 14 has a body extending along a longitudinal axis A between a leading forward end 14.1 and an opposite aft end 14.2. In this embodiment, the fuselage 14 is attached to a landing assembly 24 that facilitates the aircraft 10 engaging the ground and, for example, touching down on a surface. The assembly 24 may include wheels, for example, a pair of wheels, in a conventional manner. Alternatively, or in addition, the assembly 24 may be a fixed frame-like assembly such as is conventionally found on helicopters. The fuselage 14 may be configured to be attachable to a harness suitable for carrying a payload during use.

[0071] The empennage 18 is typically defined by a pair of spaced apart nacelle-like booms 20, 22 that are attached to the wing sections 16.1, 16.2 and extend adjacent the fuselage 14 along an axis parallel to the longitudinal axis A. The empennage 18 includes a pair of spaced apart vertical stabilizers 26, 28 with a horizontal stabilizer 30 connected between the vertical stabilizers 26, 28.

[0072] The aircraft 10 further comprises an array 32 of electric rotors 34...40 drivingly connected to suitable electric motors (not shown). The aircraft 10 is therefore a multi-rotor structure, in particular a quad-rotor structure having four rotors 34...40, each located at a corner C of an imaginary square S centered on the fuselage 12. Rotor 34 may be the forward port rotor 34, rotor 36 may be the aft port rotor 36, rotor 34 may be the forward starboard rotor 38, and rotor 40 may be the aft starboard rotor 40.

[0073] Each rotor 34...40 is drivingly coupled to a three-phase brushless AC electric motor capable of very precise speed and torque control. This makes the electric rotors 34...40 suitable for precise control to maintain hover stability. The motors are then powered by rechargeable batteries (not shown), e.g., lithium-ion batteries. The rotors 34...40 and their batteries are small relative to the forward and aft rotors (described below) to maximize the payload carried by the aircraft 10. Although not shown, in some exemplary embodiments, the electric motors may be powered by power from an onboard fuel-burning generator.

[0074] The rotors 34...40 may be controlled by any suitable commercially available flight control device.

[0075] Although electric motors are not shown, references to and control of electric rotors 34...40 are understood to refer to control of the electric motors that drive said electric rotors 34...40. Therefore, it should be noted that references to rotors 34...40 can include references to the motors that drive said rotors 34...40, unless otherwise specified. The rotors 34...40 rotate about axes that are parallel to the vertical or yaw axis Y, as shown in Figures 4 and 5.

[0076] The rotors 34...40 are fixedly mounted to the booms 20, 22 and, in use, provide vertical lift and / or stability to the aircraft 10 as described herein. In particular, the rotors 34, 36 are mounted to the boom 20 on either side of the port wing section 16.1 when viewed from above or below (see Figures 6 and 7), and the rotors 38, 40 are mounted to the boom 22 on either side of the starboard wing section 16.2 when viewed from above or below (see Figures 6 and 7). Stated differently, the rotors 34, 36 are the port rotors 34, 36 mounted to the left boom 20, while the rotors 38, 40 are the starboard rotors 38, 40 mounted to the right boom 22. The motors driving the rotors 34...40 and the batteries powering them may form part of the respective rotor assemblies and are mounted to the airframe 12 (not shown). The array 32 is typically coplanar. In particular, the rotors 34...40 are all operatively positioned in a first plane P1 operable in a coplanar manner, as can be better seen in Figure 3. The rotors 34...40 rotate about an axis J that is centered on the rotor and parallel to the vertical axis Y (see Figure 3). The rotor assembly batteries can be configured to provide at least five minutes of operation of the electric rotors 34...40, resulting in less weight on the aircraft, thereby maximizing payload.

[0077] The aircraft 10 also includes a front rotor 44 pivotally mounted to the forward end 4.1 of the fuselage 14. The front rotor 44 is displaceable, and in particular pivotable, about an axis D (see FIG. 7) parallel to the transverse axis B between a lift position, as shown in FIGS. 1-7, in which the front rotor 44 is oriented to provide vertical lift to the aircraft 10 for vertical flight, and a thrust position, as shown in FIGS. 8-12, in which the front rotor 44 is oriented to provide forward thrust to the aircraft 10 for horizontal flight. In the lift position, the axis K about which the rotor 44 rotates (see FIG. 3) is substantially parallel to the vertical or yaw axis Y, as shown in FIGS. 4 and 5. In the thrust position, the axis K about which the rotor 44 rotates is parallel to and / or aligned with the longitudinal axis A (see FIG. 10).

[0078] The aircraft 10 further includes a rear rotor 46 pivotally mounted to the aft end 14.1 of the fuselage 14. The rear rotor 46 is displaceable, and in particular pivotable, about an axis E (see FIG. 6) parallel to the transverse axis B between a lift position, as shown in FIGS. 1-7, in which the rear rotor 46 is oriented to provide vertical lift to the aircraft 10 for vertical flight, and a thrust position, as shown in FIGS. 8-12, in which the rear rotor 46 is oriented to provide forward thrust to the aircraft 10 for horizontal flight. In the lift position, the axis G (see FIG. 3) about which the rotor 46 rotates is substantially parallel to the vertical or yaw axis Y, as illustrated in FIGS. 4 and 5. In the thrust position, the axis G about which the rotor 46 rotates is parallel to and / or aligned with the longitudinal axis A (see FIG. 10). The rear rotor 46 is in a pusher configuration for horizontal flight and is vectored downward in the direction of arrow F, passing beneath the tail 18 during vertical flight (see FIG. 3). This opposes the front rotor 44, which is in a puller configuration for horizontal flight and is vectored upward in the direction of arrow G (see FIG. 3) during vertical flight.

[0079] In the lift position, the rotor 44 typically resides in a second plane P2 (see FIG. 3) that is at a lower elevation than the first plane P1. Similarly, in the lift position, the rotor 46 resides in a third plane P3 that is at a lower elevation than the second plane P2. Although not visible in the drawings, in one exemplary embodiment, the front rotor 44 and the rear rotor 46 are tilted slightly from the vertical axis by approximately 1.8 degrees in a counterclockwise direction about the longitudinal axis as viewed from the front of the aircraft.

[0080] The rotors 44, 46 are drivingly coupled to a pair of internal combustion (IC) motors or engines (not shown), which are capable of providing higher thrust than the electric rotors 34...40. In some exemplary embodiments, the motors driving the rotors 34...40 have less than half the power of the IC engines driving the rotors 44, 46. In this manner, the rotors 44, 46 provide most or all of the thrust and / or lift to the aircraft 10 during vertical flight, while the rotors 34...40 provide stability and control for the aircraft 10. In horizontal flight, the rotors 44, 46 provide all of the drive thrust to propel the aircraft 10 with lower fuel consumption from their fixed-wing fuel (approximately one-sixth the fuel used by the rotors 44, 46 during vertical flight).

[0081] The IC engine is in communication with a fuel source, such as a tank holding gasoline. Therefore, the IC motor is a gasoline engine. While the IC engine is not shown, references to and controls of the rotors 44, 46 are understood to refer to the controls of the IC engine driving the rotors 44, 46, e.g., its throttle. For this reason, it should be noted that references to the rotors 44, 46 can include references to the IC engine driving the rotors 44, 46, unless otherwise stated or apparent to one of ordinary skill in the art. In some exemplary embodiments, only the rotors 44, 46 drivingly coupled to the IC engine are displaceable in the manner described herein. However, nothing precludes displacement of parts or the entire IC engine and rotors 44, 46, even in the manner contemplated herein as a single unit. Fuel supply, appropriate throttle arrangements, transmissions, and the like associated with the IC driving rotors 44, 46 can be mounted to the airframe 12 in a balanced manner.

[0082] To balance the aircraft 10, the front rotor 44 and the rear rotor 46 are positioned equidistant from the center of gravity of the aircraft 10. Even the IC motors driving the front and rear rotors 44, 46 are spaced longitudinally along axis A equidistant from the center of gravity of the aircraft 10.

[0083] The forward rotor 44 and the aft rotor 46 are typically mounted to the fuselage 14 via vector control mounts 48 that attach the rotors 44 and 46 to the fuselage 14 and are operable to precisely vector the displacement of the rotors 44 and 46 between the thrust and lift positions described herein. As shown in FIG. 13 , the mounts 48 may be attached to both the fuselage 14 and the rotors 44, 46 and are electronically controlled via appropriate servo motors (not shown) to displace the rotors 44, 46. In particular, the mounts 48 include electrically driven rack and pinion assemblies that are coupled to the fuselage 14 via hinge joints H that allow the rotors 44, 46 and / or IC engines to move in an arc through 90 degrees to move the rotors 44, 46 from their original line of thrust to new positions above or below the original line of thrust as needed. A rack and pinion assembly 48.1 (FIG. 13) operating about hinge H (FIG. 13) provides a three-point triangular support for the rotors 44, 46 with a high reduction drive ratio, allowing for accurate positioning of the rotors 44, 46 with high available torque. The rotors 44, 46 may be mounted on a boom 48.2 controlled by the rack and pinion assembly 48.1 of the mounting 48 so as to be pivotable about hinge H.

[0084] A closed-loop feedback sensor arrangement incorporated into the control of the mountings 48 provides accurate feedback of the orientation of the rotors 44, 46, particularly information indicative of their spatial coordinates or the degree of actuation of the mountings 48 relative to the spatial orientation of the rotors 44, 46. In this manner, the mountings 48 enable accurate, reliable, and lockable displacement of the rotors 44, 46 between lift and thrust positions.

[0085] Each of the rotors 34...40 and 44, 46 includes one or more propeller blades, which may be conventional blades. It will be appreciated that during horizontal flight, the rotors 34...40 are inoperative (i.e., do not rotate during horizontal flight), while the rotors 44, 46 are operable in both vertical and horizontal flight.

[0086] 14 of the drawings, a control system for an aircraft, such as the aircraft 10 described above, is generally designated by the reference numeral 50. The system 50 typically controls the operation of the aircraft 10 and, therefore, may be integrated into the airframe 12.

[0087] System 50 includes a memory storage device 52 and a processor 54 configured to perform various data processing and control operations associated with the unmanned flight of aircraft 10 .

[0088] Processor 54 may be one or more processors in the form of a programmable processor that executes one or more electronic programs to perform actions by manipulating input data and generating output. Processor 54 may be any type of electronic device having data processing capabilities, including, by way of non-limiting example, a general-purpose processor, a graphics processing unit (GPU), a digital signal processor (DSP), a microcontroller, a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or any other electronic computing device containing one or more processors of any type, or any combination thereof. For simplicity, steps described as being performed by system 50 may be steps effectively performed by processor 54, and vice versa, unless otherwise indicated.

[0089] Memory storage devices 52 may be in the form of computer-readable media, including system memory and random access memory (RAM) devices, cache memory, non-volatile or backup memory such as programmable or flash memory, read-only memory, etc. Additionally, devices 52 may be considered to include memory storage devices physically located elsewhere in system 10, for example, any cache memory within processor 52, and any storage capacity used as virtual memory, such as, for example, stored on mass storage devices.

[0090] Electronic computer programs executable by processor 54 may be written in any type of programming language, including compiled or interpreted, declarative or procedural, and may be deployed in any form, either as stand-alone programs or as modules, components, subroutines, objects, or other units suitable for use in a computing environment. Computer programs may be deployed for execution by one processor 54 or by multiple processors 54.

[0091] The electronic computer program may be stored in memory storage 52 or in memory associated with processor 30. Those skilled in the art will appreciate that system 10 may include multiple logic components, electronics, driver circuits, peripherals, etc., not shown or discussed herein, and which will not be described herein for the sake of brevity.

[0092] The processor 54 is configured to receive sensor data from a sensor array 56, typically including a plurality of sensors configured to provide data to the processor 54, to provide the processor 54 with data that enables it to control the flight of the aircraft 10 and / or relay the information to a ground station (not shown) in use. To this end, the system 54 may include a suitable communications module, e.g., a radio frequency communications module, that facilitates communications between the aircraft 10 and the ground station in use. Communications from the ground station may remotely control the aircraft 10, for example, to take off and land vertically, hover, and fly horizontally. In one embodiment, the processor 54 may be configured to receive commands from a ground control station and, in response, to generate appropriate control signals for controlling the actuators 58 of the aircraft 54 ​​in a conventional manner. However, in the present configuration as disclosed herein, even conventional commands, such as a hover command, received remotely by the processor 54 may be transmitted to the processor 54 via a remote control system.

[0093] It will be appreciated that the methods described herein generate appropriate control signals to rotate the rotors 44, 46 to provide primary thrust to the aircraft 10, while simultaneously generating appropriate control signals to control the rotors 34, 40 to provide stability.

[0094] Alternatively, or in addition, processor 54 is configured to relay flight information to a ground control station for flight planning and override control as well as monitoring of ground processes.

[0095] The sensor array 56 may include sensors selected from the group comprising: pitot tubes, tachometers, accelerometers, gyroscopes, magnetometers, global positioning systems (GPS), thermocouples, and altimeters. The sensor array 56 may provide data associated with each sensor to the processor 54 for controlling the actuators 58. The processor 54 is configured to generate appropriate control signals to control the actuators 58 selected from the group consisting of a pair of IC engines that drive the rotors 44, 46, a vector control mount 48 that displaces the rotors 44, 46 between thrust and lift positions, electric motors that drive the rotors 34...40, and conventional aircraft flight elements such as ailerons, elevators, rudder, etc.

[0096] Processor 54 may comprise or be in communication with a suitable flight controller processor configured to control the flight, and in particular the hover maneuvers, of aircraft 10 in a conventional manner. For hover maneuvers, these flight control devices implement a feedback loop that receives data from multiple sensors and generates aircraft control signals to control the rotors via aircraft control signals and stability commands. In an exemplary embodiment, processor 54 may be configured to intercept the aircraft control signals, separate thrust and stabilization commands from the control signals, direct thrust commands to the IC motors to control rotors 44, 46 to provide the required thrust, and direct stabilization commands to the electric motors operatively connected to rotors 34...40 to stabilize the aircraft.

[0097] Those skilled in the art will appreciate that the control signals generated by processor 54 may be configured to control actuators 58 directly and / or via suitable intermediate electrical actuators. For example, in the case of an IC engine, the control signals may be configured to control a suitable electronically actuable throttle.

[0098] 1-13, a payload (not shown) of approximately 50 kg is typically attached to the fuselage 14 of the aircraft 10 in such a manner that the payload is attached to or adjacent the center of gravity of the aircraft 10. This may be via a harness attached to the airframe 12, particularly the fuselage 14, an enclosure attached to the fuselage 14, or the like.

[0099] Aircraft 10 is controlled autonomously from commands from processor 54, which is optionally interfaced with a flight control system (in some embodiments, processor 54 comprises said flight control system processor), or remotely via signals received via ground control systems. Alternatively, aircraft 10 is controlled by a combination of commands from processor 54 and ground control systems. Ground control systems may be automated or human-controlled systems that remotely transmit control signals to control aircraft 10.

[0100] In any event, the aircraft 10 is operable upon receiving appropriate commands contained in appropriate command signals to enable it to fly vertically, including maneuvers including vertical takeoff, hovering, and vertical landing, with the rotors 44, 46 pivoted to lift positions about axes D and E, respectively, via appropriate actuators receiving signals from a processor 54 that operates the mounting portion 48.

[0101] During liftoff, when the rotors 44, 46 are in the thrust position as shown in FIGS. 8-12, they are pivoted in the direction of arrows G and F, i.e., counterclockwise about axes D and E about hinge H of mounting portion 48, to the lift position shown in FIGS. 1-7. The rotors 44, 46 simultaneously rotate counterclockwise such that axes K and G move approximately 90° from their positions parallel to axes J and Y when in the thrust position, approximately perpendicular to those positions. When actuated by the IC engines, the rotors 44, 46 provide most, if not all, of the thrust to lift the aircraft 10 off the ground to a desired height in vertical flight. When the rotors 44, 46 are actuated, the electric rotors 34...40 are also typically actuated simultaneously with the rotors 44, 46 to balance and counteract the raw thrust and / or payload weight of the rotors 44, 46, providing stability to the aircraft 10 during takeoff. In particular, addressing any misalignment of the raw thrust and / or moment of the rotors 44, 46 caused by a non-symmetrical payload weight distribution about the center of gravity of the aircraft 10.

[0102] Upon reaching the desired altitude, the rotors 44, 46 are vectored and swung via the vector control mounts 48 to a thrust position, where the rotors 44, 46 provide forward thrust to propel the aircraft 10 toward its destination, thereby achieving horizontal flight. The rotors 44, 46 can be swung between the lift and thrust positions substantially simultaneously. This can be during a transition between vertical and horizontal flight, and vice versa. In this regard, the rotors 46 are swung about axis D in the direction of arrow M (see FIG. 10) substantially simultaneously as the rotors 46 are swung about axis E in the direction of arrow L (see FIG. 10) to the thrust position as illustrated in FIGS. 8-12 (where the rotors 44, 46 are parallel to each other in the thrust position as illustrated in FIGS. 8-12). Axis K and axis G of the rotors 44, 46 are aligned with shaft A. In level flight, particularly when the aircraft 10 is above the stall speed of the wings 16, the array 32 of electric rotors 34...40 is locked against rotation and therefore not used or activated.

[0103] Upon reaching its destination, as determined by an appropriate GPS unit and / or ground control, the rotors 44, 46 are again pivoted via the mountings 48 to the lift position and lowered in a controlled manner via the primary thrust rotors 44, 46 and the stabilizing rotors 34...40 to a predetermined height, e.g., controlled to hover for deploying a payload. It will be appreciated that in pivoting between the thrust and lift positions, the rear rotor 46 pivots between the gap between the tail 18 and the aft end portion 14.2 of the fuselage 14. To this end, the booms 20, 22 may have a length sufficient to space the tail 18 from the fuselage 14 to facilitate displacement of the rear rotor 46.

[0104] After deploying the payload, the aircraft 10 is controlled to climb to cruising altitude, where the rotors 44, 46 are displaced to a thrust position that moves the aircraft 10 to its original destination and / or next destination.

[0105] Once the mission is complete and the aircraft 10 is at its home location and has landed, the rotors 44, 46 are swung to a lift position, controlled by the rotors 34...40 which provide stability as the aircraft 10 returns to the ground.

[0106] Reference will now be made to block diagrams and flow charts illustrating exemplary methods in accordance with exemplary embodiments of the present invention. The methods described herein may be performed by aircraft 10 and / or control system 50 as described herein to illustrate their operation. However, nothing prevents the methods described herein from being used with other aircraft and / or control systems not described herein.

[0107] Referring to FIG. 15 of the drawings, a high level block diagram flow chart of a method for controlling the aircraft 10 is designated generally by the reference numeral 60 .

[0108] The method 60 may be responsive to receiving appropriate control signals from the ground controller and / or processor 54 in response to performing a particular maneuver selected from the group consisting of vertical flight (vertical takeoff, vertical landing, and hovering) and horizontal flight.

[0109] Depending on the required maneuver, the method 60 includes controlling the front rotor 44 and the rear rotor 46 at block 62 to be displaceable between a thrust position for horizontal flight and a lift position for vertical flight in a manner substantially as described herein.

[0110] The method 60 further includes, at block 64, controlling the front rotor 44 and the rear rotor 46 to provide the majority of vertical lift to the aircraft 10 during vertical flight when the front and rear rotors are in their lift positions. Although not shown, the method 60 also includes controlling the rotors 34...40 to provide stability control and / or lift during vertical flight. It will be understood that the lift of the rotors 34...40, or in other words, the lift provided to the aircraft 10 by the rotors 34...40, may be a fraction of the lift provided by the rotors 44, 46.

[0111] 16 of the drawings, another flowchart of a method is indicated generally by the reference numeral 70. Method 70 may be performed by processor 54 as described herein.

[0112] At block 72, the method 70 may include receiving and / or intercepting trajectory control signals including lift and / or stability commands to or for controlling the lift and / or stability of the aircraft 10 during vertical flight. As discussed above, these signals may be from a conventional flight control system configured to provide flight control for a particular aerial maneuver, such as hovering. Signals from a conventional flight control system assume that all motors on the aircraft are aligned, and thus the control signals include both thrust and stability commands.

[0113] The method 70 includes processing the received / intercepted aircraft control signals at block 74, determining and filtering commands contained in the aircraft control signals that are lift commands at block 76, and determining and filtering commands that are stability commands at block 80.

[0114] Next, the method 70 includes generating appropriate lift command signals for controlling one or more IC rotors to provide thrust to the aircraft during vertical flight, at block 78. The method 70 advantageously includes converting the lift commands into a format that controls the IC engines associated with the rotors 44, 46. This is because the received aircraft control signals assume that the rotors 44, 46 are electrical.

[0115] Thus, the lift command signal can be configured to control the appropriate throttle body associated with the IC engine to achieve the required thrust.

[0116] The method 70 includes, at block 82, generating appropriate stability command signals, including selected stability commands, to control the electric motors associated with the rotors 34...40 to provide stability to the aircraft 10 during vertical flight.

[0117] Next, the method 70 includes, at block 84, transmitting the generated signal to the respective engine / motor or associated control circuitry and / or devices.

[0118] 17-19 of the drawings, alternative configurations of an aircraft in accordance with exemplary embodiments of the present invention are generally designated by the reference numerals 200, 300, and 400, respectively.

[0119] Aircraft 200, 300, 400 are substantially similar to aircraft 10 described herein, and accordingly, the same reference numbers used in the description of aircraft 10 are used to depict like parts. Similarly, the above description, including the description of use with reference to aircraft 10, may be applied mutatis mutandis to aircraft 200, 300, 400 described herein, unless otherwise indicated or understood by one skilled in the art.

[0120] 17 and 18, the aircraft 200, 300 differ from the aircraft 10 in that the arrays of electric rotors 232, 332 are located in different positions.

[0121] In FIG. 17, electric rotors 34 and 38 are mounted on a boom similar to booms 20 and 22 described above, and the remaining electric rotors 236 and 240 are mounted on fins 218.1 and 218.2 adjacent to the tail 218 of the aircraft 200.

[0122] In FIG. 18, electric rotors 334 and 338 are mounted on winglets 316.1, 316.2 of wing 316 of aircraft 300, while electric rotors 336 and 340 are mounted on fins 318.1, 318.2 adjacent tail 318 of aircraft 300.

[0123] 19, aircraft 400 differs from aircraft 10, 200, 300 in that it does not include a tail, but does include a canard 450, a typical canard configuration. Here, electric rotors 434 and 438 are mounted on winglets 416.1 and 416.2 of wing 416 of aircraft 400, and electric rotors 436 and 440 are mounted on fins 318.1 and 318.2 adjacent canard 450 of aircraft 400. It will be appreciated that in operation, front rotor 44 is mounted between fuselage 14 and canard 40 and is movable therebetween within the zone between canard 450 and fuselage 14.

[0124] From the above, it will be appreciated that the array of electric rotors 32, 232, 332, 432 may be arranged in different configurations on the airframe to provide the desired stability during vertical flight, and particularly hovering, as described herein. Furthermore, the electric rotors further from the center of gravity may be smaller to achieve the desired stability of the aircraft during vertical flight as described herein.

[0125] Referring now to FIG. 20 in the drawings, which illustrates a diagrammatic representation of a machine in an exemplary computer system 100, a set of instructions may be executed to cause the computer to perform any one or more of the methodologies described herein. In other exemplary embodiments, the machine may operate as a standalone device or may be coupled (e.g., networked) to other machines. In exemplary networked embodiments, the machine may operate in the capacity of a server or client machine in a server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a cellular telephone, a web appliance, a network router, switch, or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by the machine. Furthermore, while only a single machine is illustrated for convenience, the term "machine" is also intended to include any collection of machines, including virtual machines, that individually or jointly execute a set (or sets) of instructions to perform any one or more of the methodologies discussed herein.

[0126] In any event, the exemplary computer system 100 includes a processor 102 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), or both), a main memory 104, and a static memory 106, which communicate with each other via a bus 108. The computer system 100 may further include a video display unit 110 (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system 100 also includes an alphanumeric input device 112 (e.g., a keyboard), a user interface (UI) navigation device 114 (e.g., a mouse or touchpad), a disk drive unit 116, a signal generation device 118 (e.g., a speaker), and a network interface device 120.

[0127] Disk drive unit 116 includes a non-transitory machine-readable medium 122 that stores a set of one or more instructions and data structures (e.g., software 124) embodied in or utilized by any one or more methodologies or functions described herein. Software 124 may also reside, completely or at least partially, within main memory 104 and / or within processor 102 during execution by computer system 100, with main memory 104 and processor 102 also constituting machine-readable media.

[0128] The software 124 may further be transmitted or received over the network 126 via the network interface device 120 using any one of a number of well-known transfer protocols (eg, HTTP).

[0129] While machine-readable medium 122 is shown in the exemplary embodiment to be a single medium, the term "machine-readable medium" may refer to a single medium or multiple media (e.g., centralized or distributed memory stores, and / or associated caches and servers) that store one or more sets of instructions. The term "machine-readable medium" may also be considered to include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by a machine, and that causes a machine to perform any one or more of the methodologies of the present invention, or that is capable of storing, encoding, or carrying data structures utilized by or associated with such set of instructions. Accordingly, the term "machine-readable medium" may be considered to include, but is not limited to, solid-state memories, optical and magnetic media, and carrier wave signals.

[0130] The invention disclosed herein advantageously provides a multi-rotor aircraft having fixed wings that allows for the vertical take-off and landing (VTOL) capabilities of a multi-rotor aircraft combined with the endurance and speed of a fixed-wing aircraft, but with a much greater payload capacity than conventional hybrid VTOL aircraft of the type contemplated herein.

[0131] In particular, the invention described herein uses all rotors (internal and electric) in hover maneuvers when the highest thrust is needed, but obtains the majority of thrust from fuselage-mounted gasoline rotors that are tilted vertically and achieve hover stability and balance through four outer vertical electric rotors. This means that the electric rotors can be very small and very light, and their lithium-ion batteries can be sized just right for short periods of hovering. In this regard, when the aircraft transitions from vertical flight to forward flight as a conventional fixed-wing aircraft, there is little weight penalty associated with the hovering rotor configuration. This is an important distinction between the aircraft disclosed herein and other prior art designs, and it allows for higher payloads and longer endurance.

[0132] Once the aircraft disclosed herein transitions to forward flight, it is supported solely by the lift generated by its high-aspect ratio wings, and its energy requirements are approximately one-sixth of the energy required for hovering. This energy is obtained from one or both fuselage and gasoline rotors configured level and at a moderate, economical cruise power setting to maximize range. The key to achieving long-range missions is ensuring that payload is maximized by carrying as little "dead weight" as possible in the form of VTOL lift rotors. The present disclosure achieves this by making the electric rotor and its battery pack as small as possible. As noted above, it will be understood that references to an electric rotor can be understood to be an electric rotor coupled to an electric motor. Similarly, an IC rotor can be understood to be an IC rotor coupled to an IC engine. In this regard, it will be understood by those skilled in the art that the use of the terms "rotor" and "motor" may be used interchangeably herein unless otherwise specified and / or will be apparent to those skilled in the art in light of the context of this specification.

[0133] Finally, lithium-ion battery packs and brushless motors have both a significant advantage and a significant disadvantage when compared to gasoline motors: they have a very high instantaneous energy density in W / kg, but a very low total energy density in kW.hrs / kg. The invention disclosed herein exploits this important advantage and negates the disadvantage through the relative sizes of the electric and gasoline motors and their use, with the electric motor providing stability primarily during vertical flight, and the front and rear rotors providing the primary thrust for vertical and horizontal flight.

[0134] In summary, the primary advantage of the invention disclosed herein is the larger payload possible relative to others, achieved by the mix of electrically and IC-powered rotors and their relative sizing, and by the fact that all rotors provide upward thrust during hover, the phase of flight requiring the highest power (thrust).

[0135] In hovering, weight is minimized (there is no weight as all rotors are providing thrust), and in forward flight, weight is minimized as the motors are small.

[0136] In level or forward flight, power (thrust) requirements are 10-25% of those needed during hovering. This is because fixed-wing aircraft are more efficient than rotorcraft in commonly known forward flight. During this flight phase, forward thrust is provided by one or both of the front and rear rotors. Electric rotors are not used in this flight phase and are therefore deadweight. However, due to their (and their battery's) small size, they have little adverse effect on the payload.

[0137] In forward flight, the aircraft flies as a normal fixed-wing aircraft.

Claims

1. In a vertical take-off and landing (VTOL) aircraft, the aircraft comprises:

1. An airframe having at least one or at least one pair of wings extending along a lateral axis, an airframe, the wings operably attached to a fuselage, the fuselage having leading and trailing ends extending between a longitudinal axis of the aircraft, and a suitable tailplane located adjacent the trailing end of the fuselage or a suitable canard located adjacent the leading end of the fuselage; an array of electric rotors operably mounted to the airframe to provide stability and / or vertical lift for the aircraft, the electric rotors being fixedly mounted to the airframe and driven by one or more suitable electric motors; a front rotor pivotally mounted to the front end of the airframe, a front rotor displaceable about an axis parallel to a lateral axis between a lift position and a thrust position, wherein in the lift position the front rotor is oriented to provide vertical lift to the aircraft for vertical flight and wherein in the thrust position the front rotor is oriented to provide forward thrust to the aircraft for horizontal flight; a rear rotor pivotally mounted to the distal end of the fuselage, the rear rotor displaceable about an axis parallel to the lateral direction between a lift position and a thrust position, in which the rear rotor is oriented to provide vertical lift to the aircraft for vertical flight, and in which the rear rotor is oriented to provide forward thrust to the aircraft for horizontal flight; Equipped with 1. An aircraft wherein one or both of said front rotor and said rear rotor are driven by one or more suitable internal combustion engines, said front rotor and rear rotor providing most or all of vertical lift to said aircraft during vertical flight when said front rotor and rear rotor are in said lift position.

2. 2. The aircraft of claim 1, wherein the front rotor is pivotally mounted between the fuselage and the canard, or the rear rotor is pivotally mounted between the fuselage and the tail.

3. the aircraft including a suitable processor, the processor comprising: receiving and / or intercepting aircraft control signals including lift and / or stability commands for the array of electric rotors and / or the front and rear rotors for controlling lift and / or stability, respectively, of the aircraft during vertical flight; using lift commands to control the front and rear rotors to provide most or all of the vertical lift for the aircraft during vertical flight; 3. An aircraft according to claim 1 or 2, configured to use stability commands to control the array of electric rotors to provide stability to the aircraft during vertical flight.

4. The processor: Processing the received / intercepted aircraft control signals to determine lift and / or stability commands; The aircraft of claim 3 , configured to filter and use the lift and / or stability commands to control the array of electric rotors and / or the front and rear rotors.

5. 5. The aircraft of any one of claims 1 to 4, wherein the front and rear rotors are driven by internal combustion engines to provide primary vertical lift to the aircraft, and the electric rotor provides primary stability to the aircraft at least during vertical flight.

6. 6. The aircraft of any one of claims 1 to 5, wherein the electric rotor is powered by a power source configured to power the electric rotor for a period of time that is shorter than a period of time that the front and rear rotors are powered by one or more internal combustion engines.

7. 7. An aircraft according to any one of claims 1 to 6, wherein each of the front and rear rotors is at least twice as powerful as one of the electric rotors and is driven by a front internal combustion engine and a rear internal combustion engine.

8. 8. The aircraft of claim 7, wherein the front and rear rotors and / or front and rear internal combustion engines are positioned equidistant from the center of gravity of the aircraft.

9. An aircraft according to any preceding claim, wherein the array of electric rotors comprises three, four, six or eight electric rotors mounted on the airframe.

10. 10. The aircraft of claim 9, wherein the array of electric rotors comprises four electric rotors positioned adjacent corners of an imaginary quadrilateral positioned symmetrically about the airframe such that the electric rotors are spaced equidistant from one another.

11. 9. The aircraft of any one of claims 1 to 8, wherein the array of electric rotors comprises a plurality of electric rotors mounted to one or more of a fuselage, wings, tail or canard, and one or more booms of the airframe.

12. An aircraft according to any preceding claim, wherein the size or power of the electric motors is inversely proportional to their distance from the centre of gravity of the aircraft.

13. An aircraft according to any preceding claim, wherein the array of electric rotors comprises substantially similar electric rotors.

14. 14. An aircraft according to any preceding claim, wherein the array of electric rotors is mounted to the airframe in a spaced apart configuration, the electric rotors being operatively coplanar and lying in a first plane, and the forward and aft rotors lying in second and third planes that are substantially coplanar and / or parallel to the first plane, in use, when the forward and aft rotors are operated into lifting positions.

15. 15. The aircraft of claim 14, wherein the second and third planes sandwich the first plane when, in use, the front and rear rotors are operated to a lifting position or when the first, second and third planes are vertically spaced apart at different heights.

16. 17. The aircraft of claim 16, wherein the forward and aft rotors are mounted to the fuselage via vector control mounts that facilitate vector control of the forward and aft rotors.

17. 17. An aircraft according to any preceding claim, wherein the front and rear rotors are slightly offset from a vertical axis in a counterclockwise direction about a longitudinal axis when viewed from the front of the aircraft.

18. 18. An aircraft as claimed in any preceding claim, wherein the front and rear rotors are tilted slightly from the vertical axis by approximately 1.8 degrees in a counterclockwise direction about a longitudinal axis as viewed from the front of the aircraft.

19. 1. A method of controlling a vertical take-off and landing (VTOL) aircraft, the aircraft comprising: a fuselage having at least one or at least one pair of wings extending along a lateral axis; an airframe, the wings being operably attached to a fuselage, the fuselage having leading and trailing ends extending between a longitudinal axis of the aircraft, and a suitable tail unit located adjacent the trailing end of the fuselage or a suitable canard unit located adjacent the leading end of the fuselage; an array of electric rotors operably mounted to the airframe to provide vertical stability and / or lift to the aircraft, the electric rotors being fixedly mounted to the airframe and driven by one or more suitable electric motors; a forward rotor pivotally mounted to the nose of the airframe, the forward rotor displaceable about an axis parallel to a lateral axis between a lift position and a thrust position, wherein in the lift position the forward rotor is oriented to provide vertical lift to the aircraft for vertical flight, and wherein in the thrust position the forward rotor is oriented to provide forward thrust to the aircraft for horizontal flight; a rear rotor pivotally mounted to the distal end of the fuselage, the rear rotor displaceable about an axis parallel to the lateral direction between a lift position and a thrust position, in which the rear rotor is oriented to provide vertical lift to the aircraft for vertical flight, and in which the rear rotor is oriented to provide forward thrust to the aircraft for horizontal flight; Equipped with one or both of the front and rear rotors are driven by one or more suitable internal combustion engines; The method comprises: controlling the front and rear rotors to be displaceable between a thrust position for horizontal flight and a lift position for vertical flight; controlling the front and rear rotors to provide most or all of the vertical lift to the aircraft in vertical flight with the front and rear rotors in a lift position; A method comprising:

20. The method comprises: receiving and / or intercepting aircraft control signals including lift and / or stability commands for controlling lift and / or stability of the aircraft during vertical flight; using the lift commands to control the front rotor and front rotor array to provide most or all of the vertical lift to the aircraft during vertical flight, and using the stability commands to control the array of electric rotors to provide stability to the aircraft during vertical flight; 20. The method of claim 19, comprising:

21. processing the received / intercepted aircraft control signals to determine lift and / or stability commands; filtering the lift and / or stability commands and using them to control the array of electric rotors and / or the front and rear rotors; 21. The method of claim 20, comprising:

22. 22. A method according to claim 20 or 21, including converting the lift command into a format for controlling the front and rear rotors.

23. 23. The method of claims 19-22, wherein the array of electric rotors is mounted to the airframe in a spaced apart configuration, the electric rotors being operatively coplanar and located in a first plane, the method including displacing the forward and aft rotors to the lift position for vertical flight, wherein in the lift position the forward and aft rotors are located in second and third planes, respectively, that are substantially coplanar with and / or parallel to the first plane when the forward and aft rotors are operated to the lift position.

24. 24. The method of claim 23, wherein the second and third planes sandwich the first plane when the front and rear rotors are operated to a lift position, or the first, second, and third planes are vertically spaced apart at different heights.

25. 22. The method of claim 20 or 21, wherein the method includes controlling the forward rotor and the forward rotor to be pivotally displaceable between the lift position and the thrust position substantially simultaneously in response to the determined lift command.

26. 1. A control system for controlling a vertical take-off and landing (VTOL) aircraft, the aircraft comprising:

1. An airframe having at least one or at least one pair of wings extending along a lateral axis, an airframe, the wings operably attached to a fuselage, the fuselage having leading and trailing ends extending between a longitudinal axis of the aircraft, and a tail unit located adjacent the trailing end of the fuselage or a canard unit located adjacent the leading end of the fuselage; an array of electric rotors operably mounted to the airframe to provide stability and / or vertical lift for the aircraft, the electric rotors being fixedly mounted to the airframe and driven by one or more suitable electric motors; a forward rotor pivotally mounted to the nose of the airframe, the forward rotor displaceable about an axis parallel to a lateral axis between a lift position and a thrust position, wherein in the lift position the forward rotor is oriented to provide vertical lift to the aircraft for vertical flight, and wherein in the thrust position the forward rotor is oriented to provide forward thrust to the aircraft for horizontal flight; a rear rotor pivotally mounted to the distal end of the fuselage, the rear rotor displaceable about an axis parallel to the lateral direction between a lift position and a thrust position, in which the rear rotor is oriented to provide vertical lift to the aircraft for vertical flight, and in which the rear rotor is oriented to provide forward thrust to the aircraft for horizontal flight; Equipped with one or both of the front and rear rotors are driven by one or more suitable internal combustion engines; The system comprises: A storage device; a processor coupled to the storage device; Equipped with the processor is configured to receive and / or intercept aircraft control signals including lift and / or stability commands to control lift and / or stability of the aircraft during vertical flight, to displaceably control the forward and aft rotors between a thrust position for horizontal flight and a lift position for vertical flight, to control the forward and aft rotors using lift commands, and to control the array of electric rotors using the stability commands during vertical flight when the forward and aft rotors are in a lift position to provide most or all of vertical lift to the aircraft and to provide stability to the aircraft during vertical flight.

27. The processor: processing the received / intercepted aircraft control signals to determine the lift command; 27. The system of claim 26, configured to filter and use the lift and / or stability commands to control the array of electric rotors and / or the front and rear rotors.

28. 28. The system of claim 26 or 27, wherein the processor is configured to convert the lift command into a format that controls the front and rear rotors.

29. A non-transitory computer-readable storage medium storing non-transitory computer-executable instructions that, when executed remotely by a suitable processor in communication with or on board a vertical take-off and landing (VTOL) aircraft, cause at least one processor to perform the steps of the method of any one of claims 19 to 25, wherein the aircraft:

1. An airframe having at least one or at least one pair of wings extending along a lateral axis, an airframe, the wings being operably attached to a fuselage, the fuselage having leading and trailing ends extending between a longitudinal axis of the aircraft, and a tailplane or suitable canard plane located adjacent the trailing end of the fuselage; an array of electric rotors operably mounted to the airframe to provide vertical lift and / or stability to the aircraft, the electric rotors being fixedly mounted to the airframe and driven by one or more suitable electric motors; a forward rotor pivotally mounted to the nose of the airframe, the forward rotor displaceable about an axis parallel to a lateral axis between a lift position and a thrust position, wherein in the lift position the forward rotor is oriented to provide vertical lift to the aircraft for vertical flight, and wherein in the thrust position the forward rotor is oriented to provide forward thrust to the aircraft for horizontal flight; a rear rotor pivotally mounted to the distal end of the fuselage, the front rotor displaceable about an axis parallel to the lateral direction between a lift position and a thrust position, in which the rear rotor is oriented to provide vertical lift to the aircraft for vertical flight, and in which the rear rotor is oriented to provide forward thrust to the aircraft for horizontal flight; Equipped with wherein one or both of the front rotor and the rear rotor are driven by one or more suitable internal combustion engines.

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