Enhanced Flight Mode

Abstract

During an aircraft's descent, the flight control system determines and maintains a glideslope determined based on a single pilot input parameter, such as the position of the control axis of the flight stick. During a landing approach, a pilot can easily select an appropriate glideslope by visually identifying the target landing site. The glideslope defines the ratio between forward and descent speeds, and while these speeds are automatically reduced during descent, the ratio is automatically set and maintained / updated according to pilot inputs. This is achieved even when both speed directions are independently controlled and affected by different aircraft mechanisms. The aircraft reaches zero or near-zero speed at the end of the glidepath, enabling a short vertical descent for landing. This relieves the pilot of the two tasks of coordinating and adjusting the forward and descent speeds to achieve a specific glideslope and then reducing the speed while maintaining that coordination.

Description

[Technical Field]

[0001] Related Applications This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 410,673, filed September 28, 2022, the contents of which are incorporated herein by reference in their entirety.

[0002] The present invention, in some embodiments, relates to the field of aircraft flight control, and more particularly, but not necessarily exclusively, to aircraft flight control during landing. [Background technology]

[0003] Multicopter aircraft designs use multiple power-driven propellers to provide vertical lift and / or horizontal thrust. Multicopters are used or proposed for a wide range of applications, including cargo and / or passenger transport. Technologies such as computer-controlled and / or sensor electronics, relatively light, high-power electric motors, increased battery energy density, and increased power generation capabilities through relatively light generators have made multicopters practical.

[0004] During flight, an aircraft is controlled in multiple axes (e.g., yaw, pitch, and roll). The aircraft has a forward speed and a rate of climb (ROC) (for descent, the ROC is negative, resulting in a "rate of descent"). Overall control of these flight parameters is typically achieved using multiple independently operating aircraft mechanisms. Often, multiple flight mechanisms affect a particular flight parameter, or a particular flight mechanism affects multiple flight parameters. Summary of the Invention

[0005] According to some embodiments of the present disclosure, there is provided a method for automatically controlling forward and descent rates of an aircraft as the aircraft descends to a landing site, the method including: adjusting a target glide slope of the aircraft in accordance with a pilot's instruction of an update to a correction to the target glide slope; automatically adjusting the ratio of the speeds as the target glide slope is adjusted so that the aircraft descends along the target glide slope; and automatically reducing the forward speed from a starting speed to a terminal speed while maintaining the ratio of the speeds to correspond to the target glide slope, wherein the starting speed and the terminal speed differ by at least half of the starting speed of the aircraft.

[0006] According to some embodiments of the present disclosure, the ending speed is less than 10% of the starting speed of the aircraft.

[0007] According to some embodiments of the present disclosure, the end velocity is a stationary velocity.

[0008] According to some embodiments of the present disclosure, the starting speed is at least 80% of the design cruise speed of the aircraft.

[0009] According to some embodiments of the present disclosure, the method includes landing the aircraft at the landing site, and when the aircraft is positioned over the landing site, the terminal velocity is reached.

[0010] According to some embodiments of the present disclosure, the aircraft decelerates from the starting speed to the ending speed while descending from a starting altitude to an ending altitude, and the ratio of the starting altitude to the ending altitude is within three times the ratio of the starting speed to the ending speed.

[0011] According to some embodiments of the present disclosure, the forward speed decreases approximately linearly as a function of altitude for at least half the range of the difference between the starting altitude and the ending altitude.

[0012] According to some embodiments of the present disclosure, the reduction in forward speed as a function of altitude includes a deceleration rate that increases for at least 10% of the difference between the starting altitude and the ending altitude.

[0013] According to some embodiments of the present disclosure, the reduction in forward speed as a function of altitude includes a deceleration rate that decreases by at least 10% of the difference between the starting altitude and the ending altitude.

[0014] According to some embodiments of the present disclosure, the forward speed decreases linearly on average as a function of altitude for at least 90% of the difference between the starting altitude and the ending altitude.

[0015] According to some embodiments of the present disclosure, the end altitude is within 2 meters vertically of the landing point.

[0016] According to some embodiments of the present disclosure, the end altitude is within 0.5 meters vertically of the landing point.

[0017] According to some embodiments of the present disclosure, the terminal velocity is less than 2 m / s.

[0018] According to some embodiments of the present disclosure, the end velocity is a stationary velocity.

[0019] According to some embodiments of the present disclosure, the final altitude and final velocity are reached at a location above the landing site.

[0020] According to some embodiments of the present disclosure, hovering the aircraft in a position above the landing site.

[0021] According to some embodiments of the present disclosure, the instruction to update the correction includes a first stage in which the correction changes the target glide slope so that the aircraft descending along the target glide slope points toward the landing site, and a second stage, after the first stage, in which the correction causes the aircraft to descend along the target glide slope while maintaining its path toward the landing site.

[0022] According to some embodiments of the present disclosure, the instruction to update the correction includes a first step in which the correction changes the target glide slope so that the aircraft's path as it descends along the target glide slope is directed away from the landing point, and a second step in which the correction adjusts the aircraft's path toward the landing point along the adjusted target glide slope.

[0023] According to some embodiments of the present disclosure, the pilot communicates the correction update instructions by adjusting axes of a flight controller.

[0024] According to some embodiments of the present disclosure, the method includes ceasing adjustment of the rate of velocity corresponding to the descent of the aircraft along the desired glide slope when the terminal velocity is reached, and using an axis of the flight controller to command a desired flight parameter other than the glide slope.

[0025] According to some embodiments of the present disclosure, the target flight parameters include movement of the aircraft along only one of a vertical altitude and a direction orthogonal to the vertical altitude.

[0026] According to some embodiments of the present disclosure, after reaching the terminal speed, the aircraft continues flying but does not adjust its altitude based on the updated indication of the correction to the target glide slope.

[0027] According to some embodiments of the present disclosure, maintaining the ratio in response to the target glide slope causes the aircraft to move along a straight glide path with a forward descending motion and constant lateral movement of the aircraft during periods when the target glide slope remains unchanged.

[0028] According to some embodiments of the present disclosure, updating the correction and subsequently maintaining a speed ratio corresponding to the desired glide slope generates a glide path that directs the aircraft toward a ground location closer or farther from the aircraft, depending on whether the correction commands a steeper or gentler desired glide slope.

[0029] According to some embodiments of the present disclosure, the commanded correction updates and subsequent maintenance of a speed ratio corresponding to the target glide slope will generate a glide path that descends toward the landing site at a relatively high descent rate with the same forward speed for a relatively steep target glide slope.

[0030] According to some embodiments of the present disclosure, the correction update instructions are determined by the pilot based on the pilot's direct visual identification of the landing site at an angle greater than 10 degrees below horizontal.

[0031] According to some embodiments of the present disclosure, the correction update instructions are determined by the pilot based on the pilot's direct visual identification of the landing site at an angle greater than 30 degrees downward from horizontal.

[0032] According to some embodiments of the present disclosure, the pilot has a direct view of the landing site through a window located within the aircraft below the pilot's waist.

[0033] According to some embodiments of the present disclosure, the pilot has a direct view of the landing site through a window located adjacent to the footrest from the pilot's perspective.

[0034] According to some embodiments of the present disclosure, the correction update instructions are determined by the pilot based on a camera view of the landing site at a downward angle of 30 degrees or more from horizontal.

[0035] According to some embodiments of the present disclosure, a flight control system for a vertical landing aircraft is provided, comprising a processor and memory, the memory containing instructions for causing the processor to: adjust a target glide slope of the aircraft in accordance with a pilot's instruction of an update to the target glide slope; automatically adjust a ratio of a forward speed and a descent rate as the target glide slope is adjusted so that the aircraft descends along the target glide slope; and automatically reduce the forward speed from a start speed to a terminal speed while maintaining the ratio to correspond to the target glide slope, wherein the start speed and the terminal speed differ by at least half of the start speed.

[0036] According to some embodiments of the present disclosure, the aircraft is provided with:

[0037] According to some embodiments of the present disclosure, the end speed is a static speed and the start speed is at least 80% of the design cruise speed of the aircraft.

[0038] According to some embodiments of the present disclosure, the aircraft decelerates from the starting speed to the ending speed while descending from a starting altitude to an ending altitude, and the ratio of the starting altitude to the ending altitude is within three times the ratio of the starting speed to the ending speed.

[0039] According to some embodiments of the present disclosure, the terminal altitude and terminal velocity are reached at a position above the landing site where the flight control system maintains the aircraft in a hover.

[0040] According to some embodiments of the present disclosure, a method is provided for a pilot to land an aircraft, the method including: viewing downward outside the aircraft through a forwardly positioned window adjacent a footrest for the pilot's feet; identifying a landing site visible downward through the forwardly positioned window; and approaching the landing site at a static forward speed while reducing speed and altitude until the aircraft lands at the landing site.

[0041] According to some embodiments of the present disclosure, the approach is performed while maintaining forward and descending speeds at rates that establish a glide slope that directs the aircraft toward the landing site.

[0042] According to some embodiments of the present disclosure, the approaching is performed while reducing forward speed as vertical distance to the landing site decreases.

[0043] According to some embodiments of the present disclosure, an aircraft is provided that includes a lower-forward positioned window having an area that is positioned below the waist of a pilot seated upright during horizontal forward flight of the aircraft, and lighting positioned to project one or more target designations into the pilot's field of view using the window as a reflective surface.

[0044] According to some embodiments of the present disclosure, there is provided a method of flying an aircraft, comprising: providing a first sequence of flight direction commands to the aircraft by moving a flight controller along an axis; and providing a second sequence of flight direction commands to the aircraft by moving the flight controller along the same axis, wherein the first sequence of flight direction commands controls a glide slope setting used to determine a glide path of the aircraft, and the second sequence of flight direction commands controls one selected from the group consisting of horizontal movement of the aircraft without vertical movement, vertical movement of the aircraft without horizontal movement, and pitch without horizontal or vertical movement of the aircraft.

[0045] According to some embodiments of the present disclosure, a vertical landing aircraft is provided that includes a computerized flight control system that operates in an enhanced flight mode for the aircraft, where the computerized flight control system maintains a fixed ratio between forward and vertical speeds of the aircraft while reducing the forward and vertical speeds to a static landing speed as a function of altitude above the ground.

[0046] According to some embodiments of the present disclosure, a transparent window facing the ground from the pilot's perspective while seated upright is provided for viewing the landing area that will be reached once static speed is reached during descent and speed reduction.

[0047] According to some embodiments of the present disclosure, a camera facing downwards towards the ground and a display that provides an indication to the pilot of the aircraft through which the landing area that will be reached when a stationary speed is reached is viewed during descent and speed reduction.

[0048] According to some embodiments of the present disclosure, a computer-controlled flight control system is provided that is configured to maintain a fixed ratio between forward and vertical speeds of the aircraft while reducing the forward and vertical speeds as a function of altitude above the ground toward a static landing speed.

[0049] According to some embodiments of the present disclosure, the static landing speed is reached in hover mode when the forward speed is zero and the altitude is near zero.

[0050] According to some embodiments of the present disclosure, the fixed ratio selects the location of the target landing area, and the fixed ratio is selected based on control stick movement adjustments.

[0051] According to some embodiments of the present disclosure, the target landing area is adjusted by changing the descent angle in response to movement of the control stick, the change including replacing the fixed ratio with a ratio corresponding to the changed descent angle.

[0052] According to some embodiments of the present disclosure, the flight control system adjusts the target landing area by varying the rate of descent and / or forward speed deceleration in response to the replaced fixed ratio.

[0053] According to some embodiments of the present disclosure, a method for vertical landing of an aircraft is provided that automatically maintains a fixed ratio between forward and vertical speeds of the aircraft while reducing the forward and vertical speeds to a static landing speed as a function of altitude above the ground.

[0054] Unless otherwise defined, all technical and / or scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, exemplary methods and / or materials are provided below. In the event of a conflict between the contents of a patent specification, including definitions, and other descriptions, the contents of the patent specification shall control. Furthermore, the materials, methods, and examples described herein are illustrative only and are not intended to necessarily limit the present disclosure.

[0055] As will be appreciated by those skilled in the art, aspects of the present disclosure may be embodied as a system, method, or computer program product. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects (e.g., a method may be implemented using “computer circuitry”), all of which may be generally referred to herein as a “circuit,” “module,” or “system.” Furthermore, some embodiments of the present disclosure may take the form of a computer program product embodied in one or more computer-readable medium(s) having computer-readable program code embodied thereon. Implementation of the methods and / or systems of some embodiments of the present disclosure may involve performing and / or completing selected tasks manually, automatically, or a combination thereof. Furthermore, depending on the actual instrumentation and equipment of some embodiments of the methods and / or systems of the present disclosure, some selected tasks may be implemented by hardware, software, or firmware, and / or a combination thereof, e.g., using an operating system.

[0056] For example, hardware for performing selected tasks according to some embodiments of the present disclosure may be implemented as a chip or circuit. As software, selected tasks according to some embodiments of the present disclosure may be implemented as a plurality of software instructions executed by a computer using any suitable operating system. In some embodiments of the present disclosure, one or more tasks performed by a method and / or system relate to a data processor (also referred to herein as a "digital processor") that operates using groups of digital bits, such as a computing platform for executing a plurality of instructions. The instruction execution elements of the processor may include, for example, one or more microprocessor chips, ASICs, and / or FPGAs. Optionally, the data processor includes volatile memory for storing instructions and / or data, and / or non-volatile storage, such as a magnetic hard disk and / or removable media, for storing instructions and / or data. Optionally, a network connection is also provided. A display and / or user input device, such as a keyboard or mouse, are also optionally provided. Any of these implementations are referred to herein more generally as an example of a computer circuit.

[0057] Any combination of one or more computer-readable media may be utilized for some embodiments of the present disclosure. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media include electrical connections having one or more wires, portable computer diskettes, hard disks, random access memory, read-only memory, erasable programmable read-only memory, optical fibers, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In the context of this specification, a computer-readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. A computer-readable storage medium may also contain or store information for use by such a program, such as, for example, data structured in a manner recorded by the computer-readable storage medium. A computer program may thereby access it, for example, as one or more tables, lists, arrays, data trees, and / or other data structures. As used herein, a computer-readable storage medium that stores data in a retrievable format as groups of digital bits is also referred to as a digital memory. It should be understood that in some embodiments, a computer-readable storage medium is also optionally used as a computer-writable storage medium in the case of a computer-readable storage medium that is not inherently read-only and / or is in a read-only state.

[0058] As used herein, a data processor is said to be "configured" to perform data processing operations so long as it is coupled to a computer-readable medium to receive instructions and / or data, process them, and / or store the results of the processing on the same or other computer-readable medium. The processing performed (optionally on data) is specified by instructions, and the processor effectively acts in accordance with the instructions. Processing operations may additionally or alternatively be referred to by one or more other terms, such as comparing, estimating, determining, calculating, identifying, associating, storing, analyzing, selecting, and / or converting. For example, in some embodiments, a digital processor receives instructions and data from a digital memory, processes the data according to the instructions, and / or stores the results of the processing in the digital memory. In some embodiments, "providing" the results of the processing includes one or more of transmitting, storing, and / or presenting the results of the processing. Presenting optionally includes showing on a display, showing by audio, printing on a printout, or otherwise providing the results in a form accessible to human sensory capabilities.

[0059] A computer-readable signal medium may include a propagated data signal having computer-readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electromagnetic, optical, or any suitable combination thereof. A computer-readable signal medium may also be a computer-readable medium that is not a computer-readable storage medium but can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0060] Program code embodied on a computer-readable medium and / or data used thereby may be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cable, RF, etc., or any combination thereof.

[0061] Computer program code for carrying out operations in some embodiments of the present disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and the like, and conventional procedural programming languages ​​such as "C" and similar programming languages. Additionally, or alternatively, a series of logical operations (optionally corresponding to computer instructions) may be embedded in the design of an ASIC and / or the configuration of an FPGA device. The program code may execute entirely on the user's computer, partially on the user's computer (e.g., as a standalone software package), partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, such as a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet Service Provider).

[0062] Some embodiments of the present disclosure may be described below with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks therein, can be implemented by computer program instructions. These computer program instructions are provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus and, when executed on the computer or data processing apparatus, generate means for implementing the functions or acts identified in the flowchart and / or block diagram blocks.

[0063] These computer program instructions may be stored on a computer-readable medium that can direct a computer, other programmable data processing apparatus, or other device to perform certain operations, such that the instructions stored on the computer-readable medium produce an article of manufacture that includes instructions that implement the functions or operations identified in the flowchart and / or block diagram blocks.

[0064] Computer program instructions may be loaded into a computer, other programmable data processing apparatus, or other device, which causes a series of operational steps to be performed on the computer, other programmable apparatus, or other device to create a computer-implemented process, and the instructions, when executed on the computer or other programmable apparatus, provide a process that implements the functions or operations identified in the flowchart and / or block diagram blocks.

[0065] Some of the methods described herein are generally designed for use by computers only and may be infeasible or impractical for purely manual execution by a human expert. For example, a human expert attempting to manually perform a similar task, such as inspecting an object, would be expected to use an entirely different method, leveraging specialized knowledge and / or the pattern recognition capabilities of the human brain, rather than manually performing each step of the methods described herein. Such a method would be much more efficient than manually performing the methods described herein sequentially. [Brief explanation of the drawings]

[0066] Certain embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings. Reference will now be made in detail to the drawings, with it being emphasized that the specific subject matter shown is by way of example only and is for purposes of illustrating embodiments of the present disclosure. In this regard, the description, taken in conjunction with the drawings, will make apparent to those skilled in the art how embodiments of the present disclosure may be practiced. [Figure 1]FIG. 1 illustrates a schematic diagram of automatic control of relative rate of climb (ROC) and forward speed to maintain a glide slope for a vertical landing aircraft on approach to a target landing site within terrain, according to some embodiments of the present disclosure. [Figure 2A] FIG. 2A illustrates a schematic representation of the elevation angle range available for direct visual selection of a landing site, according to some embodiments of the present disclosure. [Figure 2B] FIG. 2B is a schematic diagram illustrating the relationship between the glide slope constant k and the horizontal (forward velocity) and vertical (descent velocity) according to some embodiments of the present disclosure. [Figure 2C] FIG. 2C is a schematic diagram illustrating the adjustment of the glide slope constant k by directly manipulating the control stick, as viewed from the cockpit of an aircraft, according to some embodiments of the present disclosure. [Figure 2D] FIG. 2D illustrates equations for forward speed vH, rate of climb (ROC) vV, aircraft altitude h (height above the landing area), glide slope constant k, and velocity function f(h), according to some embodiments of the present disclosure. [Figure 3A] FIG. 3A illustrates a schematic diagram of ground speed versus altitude during a landing approach for a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 3B] FIG. 3B illustrates a schematic diagram of descent rate (negative ROC) versus altitude during landing approach for a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 4A] FIG. 4A illustrates schematically the stages of a landing approach for a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 4B] FIG. 4B illustrates a schematic diagram of the stages of a landing approach for a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 4C] FIG. 4C illustrates schematically the stages of a landing approach for a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 4D] FIG. 4D illustrates schematically the stages of a landing approach for a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 4E]FIG. 4E illustrates schematically the stages of a landing approach for a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 5] FIG. 5 is a schematic flow chart of a method for controlling a landing approach of a vertical landing aircraft, according to some embodiments of the present disclosure. [Figure 6] FIG. 6 illustrates a schematic of a flight control system for a vertical landing aircraft, according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0067] The present invention, in some embodiments, relates to the field of aircraft flight control, and more particularly, but not necessarily exclusively, to aircraft flight control during landing.

[0068] overview Landing Control An aspect of some embodiments of the present disclosure relates generally to systems and methods for flight landing guidance. Typical aircraft control schemes require a high degree of manual coordination during approach of a vertical landing aircraft to simultaneously control descent rate relative to ground altitude, forward speed, approach direction, and destination.

[0069] To land at a controlled airfield, conventional systems typically select a geographic location from a list or map and then appropriately adjust the map and / or aircraft controls to execute the landing, such as landing on a runway and / or landing pad, typically according to a protocol of request and permission exchanges. Landings at controlled airfields are particularly amenable to automation insofar as airfield conditions are actively monitored and maintained to facilitate safe aircraft operations.

[0070] However, in other situations, landing sites may be selected essentially on an ad hoc basis, and the selected landing site may be in unknown or changing conditions. This situation is particularly likely for sport aircraft landing sites. Short-field / vertical takeoff and landing (SVTOL) aircraft offer particular flexibility in selecting landing sites. For example, landing at a visually identified hilltop location from the air and having a picnic requires different piloting techniques and methods than landing at a controlled airfield. Examples of such aircraft include helicopters and multi-rotor aircraft.

[0071] One method for landing at a landing site is the indirect method, using a map to set parameters for an automatic or automatically assisted landing system. Continuing with the example above, a hill can be located on an electronic map (e.g., relative to the current location) and then instructed to the navigation system to locate that location as the landing destination. However, this method introduces an indirect process between the visually identified location and the actual landing site. This is because the location on the map may be incorrectly identified, and the map itself may be incomplete, out of date, or inaccurate for some other reason. Furthermore, even if the location is accurately identified, the landing site may not contain sufficient information to ensure an automatic landing. For example, there may be obstacles that the navigation system is unaware of or that the automatic landing system cannot detect. These include temporary obstacles (e.g., livestock) and permanent obstacles (e.g., fences, rocks, cables, trees, etc.).

[0072] Therefore, using common automated navigation systems (e.g., mobile-based navigational mapping systems that rely on GPS signals) to plan a route to a landing site can be dangerous. Specifically, there are risks when selecting a landing site on a map. For example, the map may be misread, or the map may not be up to date and new obstacles may exist (e.g., sheep on a hill that are not shown on the map).

[0073] Therefore, to ensure safety, pilots should approach a landing site in a manner that allows them to confirm the suitability and safety of the landing site and its surroundings. It is also recommended that pilots approach the landing site while ensuring they have sufficient time to identify obstacles that may impede landing or situations that may endanger the aircraft and avoid them. Risk naturally tends to increase near the ground. There are many irregularities on the ground, and many elements that increase the risk of collision. Furthermore, the closer the aircraft is to the ground, the shorter the reaction time for avoidance. Therefore, it is preferable to maintain visual contact with the landing site while safely and gradually reducing altitude and speed during the landing approach. For example, a pilot can visually control the aircraft while visually identifying the target landing site from within the aircraft.

[0074] However, aircraft control involves controllable elements, such as the position of control surfaces and the power levels of each motor. Control inputs have complex effects on the aircraft, often simultaneously affecting multiple elements of flight dynamics. For example, speed and pitch may be affected simultaneously. Furthermore, the same pilot's inputs may have different effects depending on the aircraft's current dynamic state (e.g., hovering versus high-speed forward flight) and the current environment (e.g., the effects of turbulence or crosswinds). This can increase the complexity of efficiently reaching the target landing point without overshooting it and maintaining the aircraft in a safe dynamic state (e.g., not traveling at excessively high speeds or approaching or exceeding safe limits of performance, responsiveness, and / or pilot perception and reaction time).

[0075] Pilot-selectable glideslope An aspect of some embodiments of the present disclosure relates to a flight and landing system and method that sets the glide slope of an aircraft as an input parameter directly controlled by the pilot. In some embodiments, the glide slope is mapped to a primary pilot control position, preferably a control axis of a flight stick (flight controller). In some embodiments, the control axis for controlling the glide slope is switchable between multiple functions depending on the flight mode. For example, this control axis may be used for altitude control during cruise flight or for fore-aft positioning over a landing site during hover.

[0076] As used herein, the term "axis" of a flight stick / flight controller refers to a control axis that provides a variable output between two extreme values, e.g., a center state of the range and multiple distinct states on either side of the center value. For example, a typical digital control axis can output integer values ​​in an 8-bit (0-255) or 16-bit (0-65535) range, optionally truncated at one or both ends of the range or with dead zones. This does not preclude the use of non-digital control axes (e.g., those based on resistance and / or voltage levels). A pilot may perceive values ​​as continuous between the extreme values ​​of the control axis. A control axis does not necessarily have to be implemented as a flight stick axis; for example, it could be implemented as a slider. Furthermore, this does not preclude pilot input from being provided by means other than a control axis. For example, a toggle switch or pushbutton configuration may be used to control the commanded slope change and / or the rate of slope change in proportion to the duration and / or number of presses.

[0077] The method of mapping pilot inputs to (target) glide slope indications can be implemented by any suitable technique and / or device. As a simple example, this mapping may be performed by a lookup table that associates raw control axis values ​​with glide slopes. However, flight computer 651 may also maintain an internal representation of the target glide slope that is relatively set and / or adjusted in response to manipulation of pilot input devices.

[0078] Thus, in some embodiments, an enhanced flight mode is provided for use with vertical landing aircraft, helicopters, or multirotors. In this mode, a computerized flight control system (e.g., flight control system 650 of FIG. 6) maintains a fixed ratio between forward speed and vertical speed while decreasing both speeds as a function of ground altitude. This ratio is fixed by a current glideslope selected by the pilot and optionally modifiable during the approach to landing. References herein to "forward speed" should be understood to refer to forward ground speed (i.e., speed relative to the ground).

[0079] This method of using the enhanced flight mode generates a linear glideslope, allowing the pilot to easily estimate the exact landing location during the approach and easing the workload associated with reducing approach speed for landing while maintaining the glideslope. This feature is particularly useful for landings at landing sites without controlled approaches, but may also be used, optionally, for descents to landing sites with controlled approaches following airport-provided landing guidance and / or air traffic controller instructions.

[0080] Direct (optionally, preferably single-axis) pilot control of the glideslope may reduce control complexity for the pilot by eliminating the need to coordinate the operation of separate aircraft subsystems that control forward speed and descent rate, respectively. To maintain the pilot-selected glideslope, the aircraft's horizontal (forward speed) and vertical (descent rate) velocities are automatically adjusted to maintain a ratio corresponding to the currently selected glideslope (e.g., the tangent of its angle). For example, a 45° descent glideslope results in equal forward speed and descent rate. A 10° descent glideslope results in forward speed approximately 5.8 times the descent rate. Optionally, the landing glidepath can be initiated from any initial speed achieved by the aircraft. The initial speed at the start of glideslope control mode is typically at least 80% of the aircraft's design cruise speed (e.g., in the range of 80-120 knots, specifically 90 knots, although other values ​​are not excluded). Optionally, the glidepath may be initiated from any initial forward or descent speed of the aircraft (absolute or relative to the design cruise speed), within constraints such as aircraft performance. The forward speed at which the pilot initiates direct glide slope input during descent is also referred to herein as the "initiation speed."

[0081] The problem with using something other than forward ground speed (e.g., forward airspeed) as a definition of forward speed is that the visual target landing point will generally not be exactly located at the end of the glideslope. However, forward airspeed measurements can be appropriately corrected for forward ground speed. Optionally, this difference can be ignored (e.g., at high altitudes or high speeds), but in that case, more frequent corrections by the pilot will be required, especially at slower forward speeds, as the relative influence of wind becomes greater.

[0082] Optionally, the landing glide path can start at any initial altitude reached by the aircraft. The initial altitude at the start of the glide path can be, for example, in the range of 100-2000 m, or an appropriate altitude depending on the aircraft characteristics and / or the flight plan, such as the cruising altitude. For example, starting at an altitude of 2000 m, a glide slope of 10° will result in a horizontal distance to the landing point of approximately 11.5 km, and a glide slope of 60° will result in a horizontal distance of approximately 0.5 km. Glide slopes starting at other altitudes are adjusted accordingly.

[0083] The altitude at which the pilot initiates direct glideslope input during descent (i.e., the altitude at which glideslope control mode begins) is also referred to herein as the "initiation altitude."

[0084] In an ideal case, once the glide path is aligned with the landing site, the aircraft descends along a constant glide slope and reaches the landing site at a speed that varies as a function of altitude above ground level. For example, speed during approach decreases as a function of altitude above ground level, reducing to a static speed that causes the aircraft to enter a static hover just above or just before the landing site. A vertical or near-vertical landing maneuver can be initiated from a static speed, preferably zero. Other altitude functions and / or parameters are described below. In some embodiments, initiating a vertical landing maneuver involves exiting glide slope control mode. This may include reassigning pilot controls previously used to command the glide slope, such as to control altitude itself or to control longitudinal positioning above the landing site.

[0085] Because the glideslope is pilot-controlled (and therefore subject to modification), it does not necessarily remain constant throughout the approach. Optionally, it may be modified at any stage of the approach. Preferably, update modifications are possible throughout the approach as long as glideslope control mode is enabled. "Update modifications" refers to the system repeatedly obtaining the state of pilot control instructions (e.g., flight controller axis positions) and using those instructions to adjust (e.g., calculate) the current desired glideslope.

[0086] During the approach, the pilot can adjust the glideslope in an intuitive manner, making it steeper, shallower, changing heading, and / or shifting the entire glideslope laterally (optionally without changing heading), effectively moving the landing point.

[0087] For example, a pilot may initially select an inappropriate glideslope, or the glideslope at the start of the landing approach mode may not be appropriate for the intended landing site. The pilot may approach from a general area and, as visibility improves, may change the landing site or select a more specific (optionally incremental) landing site. At high speeds (e.g., to slow cabin pressure buildup or maintain a safe high speed over a longer distance), it may not be desirable to descend all the way to the "average" glideslope required for landing; rather, it may be preferable to execute a steeper descent after the aircraft has slowed. Conversely, a pilot may prefer a steeper and faster initial descent phase. For example, this may be selected to observe (or simply experience) the terrain in more detail. Control and / or sensing inaccuracies may require the pilot to modify the glideslope. For example, this may be due to inaccurate ground speed sensing or wind correction. Any such variations may be naturally corrected by pilot inputs to visually steer the aircraft to a selected landing site.

[0088] Pilot's observation of the landing site Other control aspects for maintaining a preferred glide path, particularly with appropriate vehicle design, may be intuitive for the pilot or amenable to automated control with minimal risk. For example, in some embodiments, the system automates the approach to the landing site in an intuitive manner, under pilot control.

[0089] In some embodiments, "appropriate aircraft design" includes a design that allows the pilot to directly observe the terrain at a low elevation angle. For example, the "approach flight mode" (glide slope control mode) can be used for auxiliary landing maneuvers on glideslopes between 10° and 60° below the horizon. The slope angle is also determined by the pilot's visual identification of the target landing area. The glide slope approach mode is activated and initiated by visually identifying the final landing site through a window located at the pilot's feet or through a camera pointed at the landing site. The glide path is maintained linearly until the aircraft reaches a very low hover. Note that the glide path can be modified by the pilot, so the actual flight path may be curved.

[0090] Typically, the glideslope for a fixed-wing aircraft on final approach to a runway is much gentler than the above, for example in the range of 3° to 5.5° (although the latter is already considered relatively steep).

[0091] In some embodiments, an aircraft configured for steeper glideslopes includes an observation window located near the pilot's feet, e.g., positioned so that the window is at least partially obstructed by the pilot's legs and / or feet.

[0092] The observable angle of descent can optionally be changed by adjusting the pitch of the aircraft. Optionally (e.g., if the aircraft is a multi-rotor aircraft), the pilot can adjust how much the aircraft's pitch adjustments are coupled to the glideslope and / or descent rate. For example, the same glideslope can be achieved with different aircraft pitch and thruster power combinations. In some embodiments, this is in addition to the effect of wing-body lift, which is based on speed and angle of attack.

[0093] Changes in speed may constrain the aircraft's pitch, for example, constraining it to fly more level as the aircraft approaches the ground and slows to prevent excessive forward (horizontal) speed. In some embodiments, the glideslope is constrained in part by the aircraft's pitch, for example, by an angle that maintains visibility of the landing site. Such constraints are optionally applied more strictly as the aircraft approaches the ground, since maximum certainty is desired during landing. Thus, the pilot may intentionally select a (steep) glideslope initially that overtakes the target landing site, in order to obtain a gentler glideslope (and better visibility of the landing site) upon final touchdown.

[0094] A pilot can intuitively determine where on the ground they are heading by simply observing the optical flow patterns and drift in their field of view (without relying on a map or automated markings provided by the aircraft) to the extent that they can observe the terrain at the end of their current glideslope. Ideally, that ground target will appear "stationary" in their field of view, expanding as they approach from the pilot's viewing angle. Everything else will appear to drift out of their field of view, centered around that point.

[0095] In non-ideal situations (e.g., glidepath drift due to lateral aircraft movement), adjusting the glideslope directly corrects the drift by modifying the pilot's perceived "vertical" axis (up and down, but also towards and away from the pilot), whereas drift in the "horizontal" axis (left and right) may be corrected by adjusting the aircraft's angle (heading), by adjusting the aircraft's lateral speed, or both.

[0096] Having a visible landing site means that the pilot can control it to maintain a constant angular position relative to the pilot's viewpoint. Optionally, maintaining a constant position of the landing area relative to the pilot's eyes (e.g., between the pilot's legs) is key to facilitating this glide slope descent. That is, the pilot flies along a pre-determined straight line, heading toward a point displayed below the window. Even if the flight path momentarily differs significantly from the pilot's perceived direction of travel, the pilot's gradual corrections to stabilize the relative orientation of the landing site are sufficient to maintain the glide path, provided the speed is appropriately reduced as the approach progresses.

[0097] Glide slope based landing site instruction / selection However, in some embodiments, a display is provided that displays the location of the landing site estimated by the navigation computer (e.g., based on the current trajectory, including the glide slope, and based on the intersection with the Earth's surface). For example, this may be displayed as an area or location on a map display, or it may use the reflection of light projected onto a transparent panel to align with the measured or estimated position of the pilot's line of sight, thereby matching the angular position of the estimated landing site. In some embodiments, this display includes a "foot-level" reflective display, for example, using a directional lighting beam scattered or reflected off the surface of a transparent viewing window located below the pilot's waist.

[0098] Optionally, the navigation system is configured to identify, based on known map information, possible landing sites that are sufficiently large and flat throughout the area the aircraft is heading towards, and to display this information (or information in the absence of suitable landing sites) to the pilot, as well as information about landing sites that are "prohibited" for reasons other than physical suitability, if necessary.

[0099] Optionally, the aircraft and pilot collaborate to select a specific landing site through navigational selection (e.g., if multiple landing sites are still available). For example, the site closest to the currently selected glide path (or the "most suitable" site in terms of size, flatness, etc.) is highlighted, and the pilot can select it by pressing a button or other prompting means (e.g., voice confirmation). Optionally, multiple options that generally match the current glide path are presented, and the pilot can select from among them (e.g., by voice prompting, cycling through options, etc.). The landing operation then continues with the pilot remaining in control of the aircraft (e.g., including direct glide slope selection), with the selected landing site displayed to maintain the pilot's orientation and as a warning. Optionally, the pilot can instruct the navigation system to convert the glide slope-assisted landing site selection into an at least partially automated landing procedure (e.g., by hovering over the landing site along the glide slope and adjusting accordingly to reach the landing site). The pilot can also take over control again if desired (e.g., by reselecting the glide slope using the axis controllers).

[0100] Optionally, once a target landing site is selected, the navigation computer and / or the pilot working in cooperation with the navigation computer can employ more indirect navigation strategies to reach the landing site. For example, the pilot can optionally deviate from a glide path that leads directly to the landing site, while the navigation computer continues to inform the pilot as to whether the final correction falls within the aircraft's flight envelope. Optionally, the computer calculates parameters for an optimal route to the selected landing site (e.g., an optimal route in terms of energy consumption, and optionally a route that falls within performance constraint parameters such as descent rate and aircraft pitch). The computer then instructs the pilot on these parameters (e.g., by suggesting a target glideslope, which may change during descent, and the computer adjusts speed accordingly) and / or automatically guides the aircraft according to those parameters. In some embodiments, feedback to the pilot includes force feedback (e.g., to a flight controller) in response to course deviation from the selected glideslope.

[0101] Speed ​​according to altitude As another aspect of the glide path, in some embodiments, the aircraft's speed is adjusted to automatically decrease in response to a decrease in altitude.

[0102] In a typical aircraft, the final glide is a straight line, but forward speed remains nearly constant, resulting in a straight descent with a constant descent rate. However, for a human pilot, maintaining a straight line while decreasing speed (eventually decreasing speed to zero in a vertical landing aircraft) is difficult and requires continuous adjustment of the rate of climb (ROC). Reducing both speed and ROC is a highly coordinated effort, requiring control of both power and pitch, which interact with each other.

[0103] In glideslope control mode, or "approach mode," according to some embodiments of the present disclosure, the aircraft remains on a glidepath (for as long as the pilot continues to select it) and reduces speed along that line (by automatically coordinating both power and pitch). This establishes a condition in which forward or backward control stick manipulation simply changes the angle of the approach line. To the pilot, manipulating the control stick feels like moving a ground target / aiming point. In some embodiments, speed decreases linearly along a linear descent path. For example, the pilot starts at a "default" glideslope and ends at a specific ground target / aiming point toward which the aircraft is directed. The pilot simply adjusts the location of this ground target using the flight stick. In addition to selecting a glideslope, the pilot can also change the forward or backward course, for example, by changing heading or moving the aircraft laterally.

[0104] Automating (and ensuring its reliable execution) deceleration may reduce the risk from ground obstacles and allow the pilot more time to observe and respond to ground conditions and aircraft behavior. In either case, it is assumed that the forward speed (ground speed) will eventually be reduced to a static speed, low enough to initiate final landing (e.g., zero, imperceptible speed, less than 10 cm / s, or less than 1 m / s) at the landing site, or at least at a point the pilot is scanning for a suitable landing area. Optionally, the descent rate can be reduced to a static state (e.g., a short hover at a constant altitude, or a slow descent rate of 0-100 cm / s before landing) at any suitable altitude above the ground surface. This altitude is preferably high enough to ensure no contact with the ground (optionally determined by considering the possibility of unknown ground obstacles), but high enough to avoid excessively long hover times during the aircraft's descent. In some embodiments, the target altitude at which the minimum descent rate is reached is a few centimeters (e.g., 10-100 cm), and can optionally be increased to account for wind conditions, objects / irregularities at the landing site, or uncertainties therein. The altitude at which the aircraft exits glideslope control mode is also referred to herein as the "exit altitude." Optionally, the exit altitude is set to within 0.1 m, 0.5 m, 1 m, or 2 m vertically of the landing site.

[0105] The forward speed of the aircraft upon exiting glideslope control mode is also referred to herein as the "exit speed." In some embodiments, the exit speed is less than half the aircraft's starting speed, but any higher exit speed would predict that the aircraft would not be in a suitable condition for vertical landing without further action. In some embodiments, the exit speed is less than 10% of the aircraft's starting speed. In some embodiments, the exit speed is less than 2 m / s, less than 1 m / s, or less than 0.1 m / s. It is desirable for the exit speed to be a stationary speed (e.g., 0 or a speed within a range that allows the pilot to maintain stationary).

[0106] Before reaching the landing site itself, the altitude used is measured, for example, relative to the ground surface directly below the aircraft, relative to the ground surface altitude at the estimated intersection of the current glide path and the ground surface, relative to the ground surface altitude at the selected GPS coordinate, and relative to a pilot-entered or adjusted (e.g., offset) altitude. In some embodiments, the altitude-dependent speed adjustment is made relative to a static ground surface altitude reference. Optionally, the ground surface altitude reference may be dynamic, but is kept static while a particular predicted flight path is maintained. Optionally, the ground surface altitude reference changes along the predicted flight path. Optionally, the ground surface altitude reference is constrained to change relatively slowly (e.g., to avoid causing abrupt speed adjustments). The ground surface altitude reference may be changed as needed along the glide path. For example, it may change, become newly available, or become more relevant to the operation of the aircraft, according to any of the definitions above.

[0107] Optionally, the maximum elevation within a terrain area is used as the ground height reference. Optionally, the ground height reference is determined in another manner, for example, excluding peaks that the flight path is expected to avoid. The range of terrain used to determine the ground height reference is optionally selected or sized according to the current flight path. For example, the range may be selected to include the estimated end point of the current flight path. The area of ​​the range may be increased in response to higher speeds or more aggressive maneuvers (e.g., reflecting uncertainty), and conversely, may be decreased in response to lower speeds or maintaining a more constant path.

[0108] The terrain area considered in calculating altitude optionally includes terrain between the aircraft's current position and the predicted landing site, for example to prevent at least collision with terrain or passage through terrain at unacceptably high speeds, such as above 50 knots, optionally at altitudes within 20 meters of the ground and / or known ground obstacles.

[0109] Altitude-dependent functions and other velocity function parameters The main constraint on the altitude-dependent velocity function is that as the aircraft approaches the hover altitude it must reach above the landing site, the velocity must approach stationary, meaning that the velocity must at least be reduced sufficiently to allow the aircraft to remain "over" the landing site and perform a supervised landing without backing up.

[0110] For example, if the aircraft is sufficiently stationary, the pilot can perform point-keeping maneuvers to keep the aircraft near the landing site. For example, the pilot can make appropriate decisions and maneuvers within normal human reaction time to transition from a position above the landing site to a position on the landing site (landing complete), without leaving the airspace above the landing site. The landing site is optionally an area having a diameter of approximately two aircraft lengths or less. However, some embodiments are not limited to immediately exiting the glideslope control mode on the landing site.

[0111] In some embodiments, the static speed is zero for both the vertical descent speed and / or the forward speed. In some embodiments, the speed may not reach zero completely before landing (e.g., a landing with a short run is not excluded). However, at least a brief pre-landing hover is considered typical for vertical landings. In some embodiments, the glide slope control mode may be exited as the aircraft approaches the ground and landing site. For example, the end of the last selected glide path may be substituted as the target ground position and the speed adjusted to reach it, although this adjustment need not coincide with a specific glide slope. This may include switching the pilot's control mode, for example, to pilot-directed controls to directly move the aircraft forward / backward, left / right, and up / down.

[0112] For at least some glideslopes, the altitude-dependent speed function desirably establishes and maintains a ratio between forward airspeed and descent speed at the beginning of descent, thereby maintaining the same fixed ratio throughout or nearly throughout (e.g., 90%, 95%, or 99% of the time and / or distance) the range from closest to cruise forward speed to the minimum forward speed immediately prior to landing (e.g., substantially stationary or zero). For some glideslopes, maintaining this ratio throughout or nearly throughout while maintaining direct visual contact with the target point may be impractical due to aircraft pitch constraints or other reasons. Optionally, a camera provides visual confirmation of the landing point at any stage, and camera images are optionally used to confirm that the ground directly below the aircraft is clear of obstacles, particularly during landing. For some corresponding glideslopes, the aforementioned "throughout or nearly throughout" may not be achievable at all speeds. For example, a maximum gradient high-speed descent may not be possible at certain speeds due to safety and / or aerodynamic considerations, particularly in embodiments with a lifting fuselage with wings. In some embodiments, if a particular glide slope is not available at a particular altitude / speed, the aircraft's control system optionally switches the pilot's input to the closest available glide slope or otherwise issues a warning and makes corrections as necessary.

[0113] In some embodiments, the relationship between altitude and speed is selected according to constraints on the range that can be maintained or recovered in one or both directions of flight. For example, deceleration limits are typically different for one axis (forward) than for the other axis (descent), and are finite in each case. Depending on the aircraft's speed and speed ratio, aerodynamic characteristics may constrain the aircraft's attitude. For example, the aerodynamic structure with wing-body lift provided in some embodiments may function primarily as a brake at low speeds, but at high speeds, its lift may influence and limit the aircraft's independence of airhead and pitch. Another constraint that varies with altitude may be the importance of maintaining a landing point within the pilot's forward field of view. These constraints may affect the available glideslopes and how aggressively deceleration maneuvers can be applied.

[0114] Within these constraints (and any other similar constraints that may apply), the glidepath velocity at a particular glide slope is arbitrarily selected to decrease (preferably monotonically, at least on average) as a function of altitude.

[0115] A nearly constant deceleration is optional (e.g., a linear decrease to zero or near-zero velocity at the landing point) and is not required. In some embodiments, the proportional decrease in forward velocity (e.g., decrease from starting velocity to ending velocity) is approximately equal to the proportional decrease in altitude. Optionally, these two proportional decreases are set to be within 1.25, 2, 3, or 4 times of each other. For example, a "gamma (γ) constant" can be used to exponentially adjust the relationship between altitude (altitude relative to target altitude) and forward velocity. Specifically, the following formula applies:

number

[0116] Of particular note are functions that minimize the time to the landing site and functions that minimize energy use to the landing site. Constraints may be included to maintain safety and / or comfort, for example, to avoid overly dynamic acceleration at the landing site. In some embodiments, less dynamic (slower and more constant deceleration) functions are available, for example, to reduce the need for aircraft pitch changes or to prioritize crew comfort and pilot visibility of the landing site. In some embodiments, a steeper glideslope is associated with a deceleration function that aggressively optimizes time and / or energy expenditure, while a gentler glideslope tends to prioritize comfort. Optionally, the optimization (or other "style" aspects of the altitude / speed function) is selected (optionally pilot-selectable) independently of the glideslope. As an example of "style," a pilot (e.g., familiar with a particular region) may prefer a relatively fast descent to a low altitude followed by a rapid deceleration for landing. Conversely, some pilots may prefer a relatively rapid deceleration at high altitude followed by a gradual descent (e.g., to allow time to select a landing site).

[0117] In some embodiments, time, distance, or other inputs may be used as parameters to modify the altitude function that determines speed. For example, if a long flight time has elapsed since takeoff or if the landing site is still far away, adjustments may be made to prioritize energy efficiency. These parameters, along with altitude, may optionally be used in whole or in part as proxies for one another. A long distance after the landing mode is initiated can be considered a proxy for a gentler glide slope, but the altitude itself remains unchanged. However, in general, the lower the altitude at which landing is initiated, the shorter the time and distance to landing. In other words, altitude itself need not be the independent variable of the function, and strictly speaking, it need not even be an independent variable. However, "altitude" serves as a convenient metric for purposes of description in that its final value is clearly defined upon landing, and each "altitude" along the glide slope (or monotonically descending glide path) is passed against this metric only once. Therefore, references herein to "speed as a function of altitude" should be understood to be interchangeable with appropriate equivalent concepts. However, in controlling the glideslope, the pilot recognizes that he or she is also selecting the location on the ground (e.g., on one axis above the Earth's surface) to which the aircraft will descend.

[0118] Before describing at least one embodiment of the present disclosure in detail, it is to be understood that the application of the present disclosure is not necessarily limited to the details of construction, the arrangement of components, and / or the method set forth in the following description. Features described in this disclosure (including features of the present invention) may be applicable to other embodiments or may be practiced or carried out in various ways.

[0119] Glide slope controlled descent and landing parameters FIG. 1 is a schematic diagram illustrating automatic control of relative rate of climb (ROC) and forward speed to maintain a glide slope during a landing approach of a vertical landing aircraft 1 to a target landing site 3 within terrain 2, according to some embodiments of the present disclosure.

[0120] At position 10A, aircraft 1 is in the descent phase before landing, with a relatively low descent rate 12 relative to forward speed 13, which determines descent slope 11. By the time aircraft 1 reaches position 10B, the pilot has placed vertical landing aircraft 1 on glideslope 4, which is slightly steeper than descent slope 11. Glide slope 4 is maintained through positions 10C, 10D, and 10E, during which both forward speed 13 and descent rate 12 decrease, but at the same rate, thereby keeping glideslope 4 constant and maintaining a trajectory that will land the aircraft on or just above target landing site 3.

[0121] 2A is a schematic diagram illustrating the range of elevation angles available for direct visual selection of landing site 3, according to some embodiments of the present disclosure. Axis 20 indicates the direction of forward flight (horizontal) and axis 21 indicates the direction of descent (vertical), which together define circle 20A, representing the pitch plane. Typical glideslopes fall within range 22, lying between approximately 10° (glide slope 22B) and 60° (glide slope 22A) relative to the horizontal. Because the aircraft may be yawed, the glide path may not necessarily lie on the illustrated pitch plane 2A.

[0122] In some embodiments, the aircraft 1 comprises wings 10 and rotors 5 .

[0123] In some embodiments, wing 10 is a fixed wing and provides at least 25% to 75% of lift at the forward cruising speed of aircraft 1. In some embodiments, wing 10 is comprised of two sections projecting laterally from opposite sides of fuselage 6. Optionally, wing 10 is of a fixed shape (e.g., does not include aerodynamic control surfaces). Other wing configurations are not excluded (e.g., may include wings mounted on struts, biplane wings, and / or wings with movable control surfaces).

[0124] Also shown is a vertical stabilizer 7A. Optionally, a split tail configuration may be used (e.g., a vertical stabilizer on each segment of the split tail). Optionally, one or more horizontal stabilizers may be provided (either as part of the tail or as a canard configuration located forward of the wing 10).

[0125] In some embodiments, thrust is provided by rotors 5. In some embodiments, the plane of rotation 5A of each propeller of rotors 5 has a fixed orientation relative to fuselage 6 of aircraft 1. A flight control system of the aircraft optionally adjusts the pitch attitude of aircraft 1 (i.e., the angle in the pitch plane represented by circle 20A) to adjust the ratio of horizontal to vertical thrust and / or adjust the total effective thrust (e.g., thrust adjustment based on the relative velocity of airflow past the rotors affected by a selected angle at a constant rotor rotation speed). Furthermore, rotor speed, including relative rotor speed, is adjusted by the flight control system as part of adjusting the ratio of horizontal to vertical thrust or as part of adjusting the total effective thrust. Optionally, one or more control surfaces are provided to adjust the aerodynamic characteristics of the aircraft in response to airflow over the aircraft surface and / or to adjust (e.g., deflect) thrust by deflecting the airflow generated by rotors 5. In some embodiments, four rotors 5 are provided. In some embodiments, the rotor 5 is electrically powered, i.e., powered by one or more on-board batteries. Other configurations of wings, propulsion units (e.g., different types and / or numbers of engines), and / or power sources may optionally be employed in some embodiments of the present disclosure.

[0126] In some embodiments, the cockpit 7 of the aircraft 1 is configured as a high-visibility cockpit, with transparent areas on the left and right sides positioned below waist height to ensure good lateral visibility of the ground when the pilot is seated. In some embodiments, a lower forward window 8 provides a field of view below waist height for the pilot, as described, for example, in connection with the cockpit 7 of FIG. 2C . Optionally or alternatively, viewing and monitoring of the ground is performed by a camera 9, e.g., mounted onboard or externally. Optionally, the aircraft 1 can carry one or more passengers in addition to the pilot (e.g., including a passenger seated next to the pilot). For example, the aircraft's payload capacity can optionally be 150 kg or more, 200 kg or more, 250 kg or more, 350 kg or more, or 500 kg or more. In some embodiments, the aircraft's payload capacity is set within a range of 150 to 350 kg or 100 to 400 kg.

[0127] Particularly in the field of "short-range" (e.g., ranges of 120 km or less) battery-powered aircraft, constraints on battery technology (e.g., power storage density) and / or the power-to-weight ratio of electric motors combine to place significant limitations on the aircraft's payload capability and flight envelope. Due to relatively short cruise times, the landing phase of flight will account for a large portion of the energy consumption fluctuations that determine the necessary reserve in the aircraft's energy budget. In some embodiments, aircraft 1 has a rated payload capacity in the range of 200-300 kg, is intended for at least 30 minutes of flight (e.g., 30, 45, or 60 minutes), and has a maximum rated range of approximately 80-150 km (e.g., in the range of 90-120 km).

[0128] Therefore, it is understood that the ability to land from cruising speed using energy reserves reliably and predictably can be a crucial factor in the practicality of flying near the limits of rated range. This reliably predictable nature is reflected in the consistency of the time it takes to land and / or the consistency of power usage during the landing phase. This should apply even to pilots who are unfamiliar with aircraft operation and should not require excessive concentration, especially if the pilot is also selecting a landing site 3 and / or assessing its conditions. Here, "consistency" does not mean that every flight is completely identical, but rather that the pilot can plan the flight based on reliable assumptions in advance. For example, it could mean that the actual landing time and / or energy budget consumed will fall within ±10%, ±20%, or ±30% of the predicted value. For example, if a pilot can assume that the time it takes to go from cruising speed to hovering at the landing site will not exceed 10% of the flight's energy budget, then a maximum additional 3% of energy may be required when determining whether the battery's energy reserve is safe. This can pose a problem for pilots, for example, when making quick decisions and assessing acceptable aircraft performance depending on battery health, charge state, and / or weather.

[0129] In some embodiments, the difference in average landing energy budget expenditures between pilots of different skill levels (e.g., the 95% closest to the average of a randomly selected population of pilots) operating according to the same preset landing parameters is designed to be negligible or insignificant compared to the impact of variations in other flight conditions, such as weather, e.g., less than 50% or less than 25% of the impact that variations in weather have on landing energy expenditures.

[0130] 2B is a schematic diagram illustrating the relationship of horizontal velocity (forward velocity) and vertical velocity (descent velocity) with respect to glide slope constant k, according to some embodiments of the present disclosure. The instantaneous ratio of descent velocity 12 to forward velocity 13 is expressed as:

number

number

[0131] Glide slope 22B exhibits a glide slope of approximately 10°, with k = 0.18 (approximately). To maintain this slope, the rate of forward speed 13B must be proportional (at least on average) to descent speed 12B. For example, this condition can be met by maintaining the same ratio of forward deceleration 24B to descent deceleration 25B when applying deceleration for landing. For a steeper glide slope 22A, a different ratio (between forward speed 13A and descent speed 12A, and between forward deceleration 24A and descent deceleration 25A) is maintained, e.g., k = 1.75 (approximately).

[0132] Descent control by visual observation from the cockpit and glide slope control FIG. 2C is a schematic diagram illustrating direct adjustment of the glide slope constant k by a control stick from the perspective of the cockpit 7 of the aircraft 1, according to some embodiments of the present disclosure.

[0133] During descent to landing, in some embodiments of the present disclosure, the pilot uses flight controller 505 to set the current value of k (corresponding to glide slope 4). For example, pushing flight controller 505 forward increases the value of k, resulting in a correspondingly steeper rate of descent. Pulling flight controller 505 back decreases the value of k, resulting in a correspondingly gentler rate of descent.

[0134] The movement of the flight controller 505 may optionally be interpreted relatively (e.g., indicating a rate of change relative to a current state) or absolutely (e.g., the position of the flight controller 505 is directly translated into a value that sets a parameter such as a glide slope). Combinations of these are also possible, such as mid-range movement of the flight controller 505 being interpreted as absolute control relative to a particular reference point (e.g., a particular altitude), while rate of change control is applied at the extremes of the controller's operating range, and that reference point itself is also modified when the controller is returned to the mid-range.

[0135] Because aircraft responses generally have a delay to inputs, "absolute" mode operation is understood to set a target control value. The aircraft's flight control logic is preferably configured to gracefully handle flight control mode transitions so that the flight stick position prior to the transition is not interpreted in a way that causes an abrupt change in the aircraft's flight after the transition. This may include gradually changing the flight controller's interpretation of the axes. For example, this may include a gradual change in interpretation between relative and absolute control modes, or a gradual change in the flight controller's interpretation of position as the aircraft transitions between different flight control modes.

[0136] Directly linking the flight controller 505 control axes to k and glide slope 4 is desirable as a special mode of aircraft operation. For example, during cruise flight, the same control axes are optionally configured to correspond to other directly controlled parameters, such as rate of climb, aircraft pitch, throttle, or a combination of two or more of these.

[0137] The glideslope of an aircraft landing is typically influenced by the operation of flight controller 505, for example, by modifying the aircraft's flight control surfaces. However, it is emphasized that the actual glideslope is typically influenced by additional factors, particularly the aircraft's airspeed. A skilled pilot must balance these factors with inputs via flight controller 505 to keep the aircraft on the correct path. In embodiments of the present disclosure, maintaining this balance is the responsibility of the aircraft itself.

[0138] In general, "heading" is not necessarily guaranteed, nor is it the default behavior, of an aircraft in flight. Particularly during landing maneuvers, fixed-wing aircraft typically point their nose away from the ground. Also, in embodiments of the present disclosure, selecting a glide slope should be distinguished from matching the aircraft's attitude (particularly pitch) to the glide slope. In some embodiments, even if the flight controller 505 is held in a constant position, the aircraft's pitch may be varied as part of adjustments to maintain a constant ratio of forward speed to descent speed.

[0139] The time from the moment the pilot adjusts the glideslope and sets the target point to the moment the aircraft reaches a glideslope that, if maintained, will reach the target point is typically on the order of a few seconds; for example, it could take 1 to 20 seconds for the aircraft to automatically adjust toward the landing point. Optionally, a longer time may be used to dampen the aircraft's dynamic behavior. For aircraft that rely primarily on rotor lift, reducing rotor thrust and increasing vertical descent rate as needed to achieve a rapid adjustment may be particularly effective. After the glideslope is set, the pilot is preferably free to make appropriate update corrections for the remainder of the flight (e.g., until the terminal speed / altitude is reached). If the initial course is appropriate and other conditions are stable, the pilot may optionally choose to leave the update unchanged.

[0140] If the pilot makes an error in the initial glideslope command, he or she may initially believe that the glideslope is correctly established, but during the descent, he or she may realize that the aircraft is not heading directly toward the landing site (e.g., because the landing site is drifting within view). This may necessarily lead the pilot to enter a phase of issuing corrective commands to the aircraft, for example, to issue commands to adjust the angular position of the target landing site to stabilize it. Optionally, for example, there may be no strong constraint on the size of the allowable range of commands to change the selected landing site. Optionally, the aircraft control system may be less sensitive to the pilot's corrective commands after an initially determined stable selection is made, for example, to help prevent excessive corrections as the pilot makes fine adjustments.

[0141] On steep descent slopes (e.g., angles below the horizon between 10° and 60°), it may be advantageous for the aircraft to provide the pilot with a direct, low-angle forward view. In some embodiments of the present disclosure, this is accomplished by providing a lower forward window 8 that extends upward from approximately the height of the pilot's feet 501 when seated upright. In some embodiments, the footrest 501A provides this height reference. In other words, in level flight, the window provides a viewing area below the plane of the pilot's hips.

[0142] Thus, a target landing point 3 on or near the current glideslope 4 of the aircraft 1 may appear to the pilot to be located beyond the forward lower window 8.

[0143] In the example of Figure 2C, aircraft 1's current heading is located at the intersection of horizon 503 (which indicates aircraft 1's rate of climb) and vertical 502 (its heading). Because the aircraft is not necessarily "headed" in its direction of travel, this intersection point is not necessarily in a consistent or predictable location within the pilot's field of view. Instead (assuming the aircraft's pitch angle α is constant), adjusting k up or down affects the glide slope such that horizon 503 (and therefore the aircraft's "predicted touchdown point" with the ground) is correspondingly (but in the opposite direction) adjusted downward and upward (the movement indicated by -k and the arrows in the figure). This "down and up" also corresponds to "near and far" in this case because the ground is being viewed from an oblique angle.

[0144] In some circumstances, pitch angle α may also change as k changes, or in response to other factors (e.g., a decrease in speed). This change alone can significantly change the position in the field of view (angle relative to the pilot) of the intersection of horizontal line 503 and vertical line 502, but this does not necessarily have a direct effect on the position of this intersection on the Earth's surface.

[0145] Although pilots generally cannot determine the current target landing point solely from its relative angular position in the visual field, the target landing point (the aircraft's current ground-oriented heading) may be perceived from the overall pattern of optical flow around it (e.g., the flow indicated by arrow 504). If this location is stable (e.g., there is no sideslip and the aircraft's attitude and glideslope are not changing), this point will appear to "expand" while remaining angularly fixed in the visual field, with the rest of the area appearing to move outward. However, at longer distances or at slower speeds, perceptually identifying the center of optical flow may be difficult.

[0146] Even in this case, the pilot can intuitively and easily approach the aircraft toward the visible landing site 3 by manipulating the flight controller 505 to maintain a constant apparent (angular) position of the target landing site 3. However, this only applies if the aircraft is simply continuing to approach the landing site and no pitch change is required to reduce speed. If a pitch change occurs, the pilot can take that change into account and allow the angular position of the landing site 3 to move, without necessarily knowing the exact amount of displacement. For example, the shifting horizon provides an intuitive visual clue that a pitch change is occurring. The sense of balance also provides a sensory clue, at least during gradual deceleration.

[0147] Even if aircraft 1's instantaneous heading is consistently off course (e.g., due to the pilot's misperception of its actual heading), continuous corrections by the pilot will gradually bring the aircraft curvilinearly toward the intended landing site. For example, at a distance of several kilometers, a 15° error in heading will have a significant impact, but continuous corrections made during final approach will cause the absolute error to decrease over time. By the time the aircraft approaches within a few meters of the landing site, that same 15° error will have a much smaller impact, at which point the pilot can easily determine, intuitively and visually, the true heading of the slowing aircraft and adjust his corrections accordingly.

[0148] Also shown in Figure 2C is a flight instrument panel 506. In some embodiments, this panel displays information that the pilot can use to additionally or alternatively identify and / or confirm the location of the current target landing point. For example, the flight navigation computer may calculate the intersection of the current target point with the ground and, optionally, display this information as a map and provide it to the pilot. As another example, the flight navigation computer may optionally provide a display that mimics the pilot's field of view, showing the direction of the current target intersection with the ground from the pilot's subjective perspective. As yet another example, lighting (e.g., a dot, crosshairs, text, and / or graphic symbols) may be projected onto the forward lower window 8 itself and controlled to indicate the intersection of the current target point with the ground from the pilot's perspective.

[0149] Optionally or alternatively, the navigation system may use the pilot's navigation input to identify a point to which the pilot is heading (e.g., a distant point held at a fixed angular position within view). If this point does not match the aircraft's current course, the navigation system may suggest course adjustments to the pilot. Optionally, the navigation system itself may adjust the aircraft's operation to assist the pilot. In some embodiments, the navigation system may present the pilot with an estimate of the pilot's intent, providing the pilot with an opportunity to confirm or modify the estimate.

[0150] In some embodiments, after the pilot and navigation system mutually confirm the target landing site, additional functionality may become available. For example, the navigation system optionally automatically controls flight operations to reach the target landing site, with the pilot's permission, and suggests faster and / or more energy-efficient routes to the pilot. In some embodiments, the flight system evaluates the target landing site using available maps and / or sensor data to, for example, detect the presence of obstacles that may not yet be visible to the aircraft, verify that the landing site is sufficiently flat, determine whether it may be affected by avalanches or landslides, or check for known landing rights issues. Optionally, these checks may be performed on the intersection of the currently targeted path and the terrain, even if the pilot has not explicitly confirmed it as the target landing site.

[0151] Function-based parameter control in glideslope controlled descent. FIG. 2D illustrates a forward velocity v H , rate of descent (ROC)v v , the aircraft altitude h (altitude above the landing zone), the glide slope constant k, and the velocity function f(h).

[0152]

number

[0153]

number

[0154] Speed ​​reduction as a function of altitude 3A and 3B are schematic diagrams illustrating ground speed versus altitude during a landing approach for a vertical landing aircraft 1, according to some embodiments of the present disclosure. FIG. 3B is a schematic diagram illustrating descent rate (negative ROC) versus altitude during a landing approach for a vertical landing aircraft 1, according to some embodiments of the present disclosure.

[0155] This reflects the implementation of two control loops: rate of descent (ROC) and forward speed. For example, optionally, forward speed is set as a linear function of ground altitude, offset at a certain minimum altitude where a minimum speed is reached, or where glide slope control mode ends. A maximum altitude above which speed will not increase is also set.

[0156] The rate of descent (ROC) also shares these characteristics, e.g., having a maximum value above a certain altitude and reaching zero at least during landing. It also optionally reaches zero at an offset altitude, at which point the pilot can exercise direct control of altitude (e.g., instead of controlling the descent slope), allowing ample time to respond appropriately. In some embodiments, this can be thought of as manipulating the ROC in real time using the stick; for example, pushing the stick forward increases the ROC in a negative direction (increasing the rate of descent) and makes the approach steeper. Conversely, pulling the stick back decreases the rate of descent and makes the approach more gradual. If deceleration is linear as a function of altitude, a steeper approach reduces both forward and descent rates more quickly as a function of time (e.g., the aircraft reaches the ground and reaches minimum forward speed sooner). However, when compared at the same altitude, a steeper approach will descend faster than a gradual approach, while optionally maintaining the same forward speed. Note that linear deceleration is not maintained in all embodiments.

[0157] In Figure 3A, three paths 42, 42A, 42B leading from point 40 on the approach slope to a final landing speed / altitude envelope 44 show different relationships between altitude and ground speed (level / forward flight speed). Path 42 shows a linear relationship between altitude and speed, where forward speed decreases proportionally as altitude decreases along a particular glide slope. Optionally, path 42 represents this relationship for a selected desired glide slope, where the steeper the glide slope, the greater the deceleration rate.

[0158] However, the relationship between ground speed and altitude does not necessarily have to be linear. Path 42A represents a case where speed decreases earlier ("faster") than in the linear case. This increases the time to landing, but potentially provides more opportunity to observe (and correct or change, if necessary) the target landing site. Path 42B represents a case where speed is maintained longer than in the linear case. This reduces the time to landing. Such a pattern can be useful to conserve available energy. It can also be useful when the pilot is confident in the suitability of the landing site.

[0159] Note that paths 42, 42A, and 42B (including paths in between) are all compatible with maintaining a constant glideslope (even if it is the same constant glideslope). Alternatively, the glideslope can be changed during the descent while maintaining a specific relationship between altitude and forward speed. In some embodiments, the ground speed vs. altitude relationship used is selected based on the "aggressiveness" of the descent. For example, a steeper descent slope (already resulting in faster deceleration in linear path 42) may be associated with path 42A, which decelerates more rapidly, thereby providing an additional safety margin and time for evaluation of the landing site. On the other hand, a more gradual descent may involve slower speed reductions (as with path 42B) depending on altitude, thereby avoiding unnecessary increases in flight distance, etc.

[0160] Also, a steeper angle of descent may optionally be interpreted as an intent to hasten the descent, leading to a slower deceleration as a function of altitude. Conversely, a gentler angle of descent may be interpreted as indicating a greater reduction in speed. For example, a gentler angle of descent may be interpreted as indicating an interest in staying aloft for the purpose of observing the area.

[0161] Optionally, multiple deceleration modes are available, and the navigation computer of aircraft 1 allows the pilot to select the mode appropriate for the situation. Optionally, the pilot can select the relationship between altitude and speed, for example, by selecting an exponential factor to convert from linear deceleration to a "super-linear" (e.g., path 42A) or "sub-linear" (e.g., path 42B) deceleration profile. Optionally, this selection is based on the throttle input setting. For example, the harder the throttle trigger is squeezed, the more gradual the altitude / speed decrease (i.e., a change from the current setting to a more gradual deceleration).

[0162] The selection of glideslope k is under the pilot's control at any time, for example, by manipulating the axes of a flight controller, and can optionally be changed at any time during the descent, for example, to modify it to select a new landing site. If k is tied to a speed-altitude function, the aircraft interprets this as a command to optionally increase or decrease speed as needed to match the "new" path. Alternatively, the aircraft can continue using the originally selected ground speed and altitude relationship, slowing down but not accelerating, or it can transition partially depending on the amount of speed and / or altitude reduction.

[0163] The vertical descent of line 43C represents a decrease in altitude at forward cruise speed; once a certain threshold altitude is reached, the aircraft transitions to glideslope control (e.g., direct pilot glideslope selection via flight controller axes). However, transition to glideslope control can also be accomplished by other methods. Area 43 indicates a range of possible paths leading to glideslope control transition. For example, a direct descent below a certain cruise speed along line 43A can be triggered only when the altitude / speed relationship intersects with the altitude / speed function to be used during landing descent. Path 43B represents a descent from an overspeed condition. Optionally, the altitude-speed relationship is applied to higher altitudes (even if glideslope control is not yet enabled) to ensure a smooth transition. Alternatively, deceleration begins after glideslope control is enabled (e.g., below the altitude of point 40). Optionally, when the aircraft enters glideslope control mode, the altitude-speed relationship is simply scaled to match the current speed. Additionally, as an alternative, the transition to glide slope control mode itself may occur at a higher or lower altitude, allowing the initial deceleration to begin earlier or later.

[0164] The final landing speed / altitude envelope 44 represents the case where forward speed is actually reduced to zero over the landing target followed by a full vertical descent, or where the aircraft continues to decelerate while maintaining a low, but non-zero, forward speed as it completes landing. This diagram does not show a non-zero forward speed during landing (i.e., a rolling landing), but this is not excluded.

[0165] The points made regarding paths 42, 42A, and 42B in FIG. 3A also generally apply, mutatis mutandis, to paths 52, 52A, and 52B in the altitude-descent rate graph of FIG. 3B. In the illustrated situation, it is assumed that the initial descent rate (e.g., within region 53 bounded by paths 53A and 53B) is likely to not necessarily match the glideslope initially selected by the pilot. As with the forward speed, several approaches to address this are possible. The illustrated option is to adjust the descent rate as the aircraft descends and transitions to on-slope conditions at point 50 to match a suitable "start" value (e.g., a value determined to be an appropriate ratio to the current forward speed). Pilot inputs from point 50 onward are then interpreted relative to the value reached. Optionally, no such preliminary matching is performed, and the current descent rate (as a ratio to the forward speed) at the time of transition to glideslope control becomes the initially selected glideslope. Optionally, the altitude-speed relationship is handled in the manner described for the ground speed versus altitude graph. Upon landing, the descent rate must remain above zero until contact with the ground occurs.

[0166] Controls and pilot cues during landing descent 4A-4E are schematic diagrams illustrating the stages of a landing approach for a vertical landing aircraft 1 according to some embodiments of the present disclosure.

[0167] In FIG. 4A , aircraft 1 is in forward flight with forward speed 413A and descent speed 412A, resulting in glideslope 415A. In some embodiments, aircraft 1 is a fixed-rotor, fixed-wing aircraft with dynamic characteristics such that at high forward speeds, the majority of lift is generated by wings 10. Furthermore, the pitch of aircraft 1 adjusts the contribution of thrust generated by rotor 5 to lift (vertical) and forward speed (horizontal). Pitch can also affect total thrust depending on the difference between horizontal and vertical airspeeds. Such dynamic interactions are potentially complex in terms of their direct effect on aircraft speed. However, during direct glideslope control by the pilot, this complexity is absorbed by the flight control system of aircraft 1 and is not directly affected by the pilot.

[0168] In some embodiments, the pilot's control of the aircraft is modal. For example, a mode change is optionally performed from cruise flight to final approach (glide slope control), and optionally from glide slope control mode to vertical descent mode. Other flight modes, such as takeoff, climb to cruise flight, and sport flight, may also be performed. Optionally, one or more mode changes are automatic. For example, a transition from cruise flight mode to glide slope control mode is automatically triggered when the aircraft descends below a certain altitude. Optionally, the pilot can manually induce or reverse a flight mode change (e.g., cancel an automatic mode change) under certain circumstances. Mode changes may be instantaneous, but are not necessarily so. For example, the pilot's input to certain axes of the flight controller 505 may be interpreted gradually depending on the situation, such as gradually reducing the influence of thrust adjustments while simultaneously gradually increasing the influence of glide slope adjustments.

[0169] In the illustrated situation, the pilot has a distant view of landing site 3, with its angular size and direction in the field of view indicated by 410A. The angular size and distance to the landing site are not to scale, but in this illustration, the angular size is at its "smallest" and the distance is at its greatest. Because glideslope 415A is not within the angular position of landing site 3, aircraft 1 is overshooting, as indicated by right-pointing arrow 411A. Perceptually, the pilot may perceive this overshoot as landing site 3 drifting downward or closer in the lower part of the field of view.

[0170] 4A may correspond to a pre-landing flight phase before direct pilot control of the glideslope is enabled, where the glideslope 415A is the result of other commanded flight conditions of the aircraft 1, such as thrust and / or pitch adjustment inputs by the pilot.

[0171] 4A may correspond to a phase of flight in which a mode allowing direct pilot control of the glideslope has been enabled (e.g., at the pilot's request or as a result of descending to the mode start altitude), but in this case the pilot has not yet steered the aircraft 1 toward its final landing location.

[0172] At the time of Figure 4B, direct pilot control of the glideslope has been enabled, and the pilot is manipulating the glideslope control axis of flight controller 505 to adjust glideslope 415B so that the aircraft's glideslope coincides with the (slightly larger) angle of sight 410B created by landing site 3. In this case, the descent angle is 45°, and forward speed 413B and descent speed 412B are equal.

[0173] Optionally, the pilot's glideslope control input may result in an angular change 414B in the pitch α of the aircraft 1. For example, in response to the pilot's input to descend the glideslope, the flight control system of the aircraft 1 may (1) reduce thrust to increase the descent rate 412B and (2) increase the proportion of rotor thrust provided in a forward direction so that the forward rate 413B is maintained at the pilot-commanded ratio k to the descent rate 412B. During the pitch adjustment, the pilot may perceive landing site 3 as drifting (e.g., upward / away in this case) in his or her field of view, even though the aircraft 1 is actually on a glide path to landing site 3. However, pitch adjustments made in immediate response to the pilot's glideslope-changing input may be rapid enough for the pilot to recognize them as the result of his or her input, and these adjustments may end immediately when the pilot stops changing the glideslope.

[0174] In FIG. 4C, glide slope 415C remains within the viewing angle 410C created by target landing site 3, and forward velocity 413C and descent velocity 412C are again decreasing at a constant rate.

[0175] However, even though the pilot-commanded glideslope 415C remains unchanged and remains centered within the viewing angle 410C subtended by the landing site 3, the pitch α returns to a more horizontal attitude, as indicated by arrow 414C. This may be the result of, for example, the flight control system of the aircraft 1 attempting to continue reducing the forward speed 413C and the descent speed 412C at a fixed ratio. For example, the amount of lift provided by the wing 10 may have decreased sufficiently to require a greater contribution of vertical thrust from the rotor 5. To avoid the increased forward thrust, the aircraft 1 pitches back horizontally.

[0176] In some cases, automatic pitch adjustments made as part of speed reductions due to altitude loss may cause the pilot to perceive a stronger illusion of course drift (e.g., a movement toward the near field / downward, as indicated by arrow 411C). However, the pilot may be able to intuitively distinguish between a movement of the entire field of view (due to a change in pitch) and a movement of a stable portion of the field of view (due to a change in the glideslope itself). Furthermore, as LZ3 approaches, it becomes easier to ensure that LZ3 remains centered in the optical flow of the approaching terrain. Nevertheless, even if the pilot mistakenly attempts to "correct" this illusion, the continued intuitive awareness of stabilizing LZ3's angular orientation will ultimately guide the aircraft toward the intended destination.

[0177] 4D, glide slope 415D remains within the viewing angle 410D of the currently approaching target glide slope, LZ 3, and forward speed 413C and descent speed 412C are again reduced at a fixed rate. At this point, the apparent size (and viewing angle 410D) of LZ 3 has increased sufficiently that portions of it may be obscured from the pilot's view, but the pilot can still see enough of the surroundings and / or LZ 3 itself to maintain his or her sense of orientation.

[0178] The aircraft's pitch α has been further adjusted by angle change 414D, with rotor 5 positioned horizontally or nearly horizontally, optionally with small adjustments (e.g., tilting backward) to continue counteracting forward velocity 413D. At this point, the pilot has strong visual cues regarding his absolute motion relative to landing site 3, which may prevent him from being confused by illusory effects regarding the aircraft's glideslope.

[0179] In the situation of Figure 4E, the aircraft 1 has reached the end of its glide path and is completely over the landing site 3, the forward velocity is cancelled and the subsequent descent velocity 412E is maintained at a low level to achieve a safe landing. In static hover mode, all thrust is directed vertically, e.g., α is 0.

[0180] Optionally, glide slope mode is disengaged at this point. Optionally, operation of the corresponding axes of the flight controller previously used to set the glide slope may now be used to control the descent rate 412E of the aircraft 1. At this stage, the pilot can monitor the position and / or status of the landing site 3 (e.g., within the viewing angle range 410E) by viewing multiple directions (e.g., including to the sides of the aircraft 1). The flight control system of the aircraft 1 may optionally be configured to make small angular adjustments 414E to the pitch α as needed to maintain point-keeping relative to the on-site position.

[0181] Optionally, the transition from glide slope mode to final vertical descent mode is performed in a gradual (smooth) manner, such that the glide slope response of aircraft 1 to position changes of flight controller 505 gradually weakens as a function of altitude above the ground to favor control of vertical position and / or velocity. This change may be asymmetric, e.g., faster in the direction of increasing descent and delayed in the other direction such that a gradual forward progression by the pilot does not necessarily result in an increase in altitude (or a less pronounced increase).

[0182] Glideslope Control Mode Operation FIG. 5 is a flow chart that schematically illustrates a method for controlling the landing approach of a vertical landing aircraft 1, according to some embodiments of the present disclosure.

[0183] At block 602, the flowchart begins.

[0184] In block 604, in some embodiments, the aircraft's flight control system monitors aircraft states and / or pilot inputs to determine whether conditions are met to initiate glide slope control of the aircraft. Optionally, glide slope control is initiated by explicit pilot command. Optionally, conditions for automatic switching include descent below a certain altitude, which may optionally be conditioned based on past events, such as a period of flight at cruising speed above that altitude. In some embodiments, switching to emergency glide slope control mode is initiated when the remaining battery power is low (and / or other energy reserve is limited), when damage and / or malfunction (e.g., rotor failure) is detected, etc.

[0185] From block 606, in some embodiments, if the conditions for initiating glideslope control mode are met, the flowchart proceeds to block 610. Otherwise, the flowchart returns to block 604.

[0186] In block 610, in some embodiments, the aircraft altitude h, forward (horizontal) velocity v H , descent (vertical) velocity v V , and the current pilot-commanded glideslope k are obtained. In some embodiments, the pilot-commanded glideslope k is provided in response to a flight controller operation, for example, the movement of a particular axis of the flight controller.

[0187] A flight controller (e.g., flight controller 505) optionally includes multiple control axes, including primary axes corresponding to left-right and forward-backward movement of a control stick, a rotational axis (e.g., rotation about a geometric axis passing through the longitudinal axis of the control stick), and one or more secondary axes, such as a directional selection switch, a two-axis "hat" joystick, one or more throttle axes, and optionally one or more buttons. Preferably, when glide slope control is initiated, the primary longitudinal axis of the flight controller becomes the direct glide slope control axis. Optionally, another axis (e.g., one axis of a two-axis "hat" joystick) is used instead. The glide slope control axis is optionally interpreted as indicating the glide slope relatively, absolutely, or a combination thereof, and may include, for example, the form described in connection with FIG. 2C .

[0188] In block 612, in some embodiments, the value obtained in block 610 is compared using a function f(h). This function f(h) may be constructed, for example, according to the principles described in connection with FIGS. 3A and 3B. Optionally, f(h) is modulated by additional input from the pilot, for example, to adjust whether deceleration occurs slowly or quickly initially. Additionally, other factors optionally influence f(h). Such factors include, for example, flight time, current speed, current distance to the ground (e.g., distance along the current glide path), distance to a previously targeted landing site, etc. Also, optionally, "altitude" as an independent variable of the speed function is replaced by one or more parameters, such as the target time to landing or the remaining distance to the landing site. Conversely, "altitude" may be understood as a proxy for such parameters and / or combinations of parameters. However, altitude itself is particularly significant in that the end condition for landing is zero altitude above the ground. The altitude itself may be defined in a variety of ways, for example as described in the overview, and the definition used is optionally changed dynamically during landing depending on the approach to the landing site and / or the characteristics of the intervening terrain.

[0189] In some cases, a discrepancy may occur between the speed obtained by applying the function f(h) and the actual speed of the aircraft. For example, the aircraft may enter glide slope control mode at a speed and altitude that is not on the altitude / speed function. Optionally, this is avoided by scaling the function f(h) to match the current flight parameters, and the speed reduction proceeds from there. Optionally, excessive deviations prevent entry into glide slope mode and / or cause an exit from glide slope mode. In some embodiments, the function f(h) is defined to allow approaches at multiple different parameter combinations, optionally including appropriate "funneling" to adjust the aircraft's flight parameters to the standard flight envelope used during glide slope control mode.

[0190] In fully relative mode, the commanded glideslope value k and the actual descent rate v V and forward speed v H Discrepancies between the ratio of k and k are optionally avoided by treating the flight controller axis positions as commanding the rate of change of k from its current value. This has the advantage that it may allow a center position (optionally with a "dead zone" that is not responsive to its surroundings) to be indicated as no commanded change, making it easier for the pilot to interpret sensory perception. The commanded rate of change may not be achieved instantly due to factors such as response delay, but the pilot can adjust by waiting for the cumulative effect.

[0191] However, in some embodiments, the flight controller axis positions dictate (at least in part) the target value of k, in which case the goal of control by the aircraft's flight control system is to reduce the discrepancy between the commanded k and the actual k over time.

[0192] As previously mentioned, for example, as shown in connection with Figures 3A-3B, there are optionally different ranges of altitude and speed functions that the aircraft can travel from a given current altitude and speed. The ranges are optionally selected automatically or by pilot selection. Optionally, the ranges are selected by predetermined selection. Optionally, the ranges are selected dynamically according to changing current conditions and / or pilot inputs.

[0193] In block 614, in some embodiments, the aircraft's current flight characteristics are adjusted accordingly to determine the aircraft's altitude, h, forward (horizontal) speed, v H , descent (vertical) velocity v V , and the predicted measured glide slope k currently commanded by the pilot are brought into closer or continued mutual alignment with respect to the function f(h). In general, glide slope control flight translates the pilot's selected or changed glide slope k into adjustments to the aircraft's flight parameters to adjust the actual descent rate v V and forward velocity v H to match the specified k ratio. This is achieved, for example, by appropriate adjustment of thrust, aircraft pitch, and optionally by adjusting other parameters such as wing shape, activation of secondary thrusters, movement of thrust vectoring surfaces, etc.

[0194] At the same time, the descent speed v V and forward speed v H is reduced so that vV=0 at least approximately when the aircraft finally reaches an offset altitude hoffset above the ground. As noted above, the reduction may be linear or may follow some other function. There may be multiple different but coordinated changes occurring simultaneously to the aircraft's flight parameters. Some of these changes may affect one of the two speeds more or less independently, while others may result in closely correlated (or anti-correlated) changes to the forward and descent speeds.

[0195] If alignment with f(h) has already been established, the adjustments in block 614 may include maintaining the current flight characteristics (e.g., continuing the existing rate of reduction in motor power) and / or adjusting them incrementally (e.g., gradually adjusting the pitch of the aircraft to suit the current relative contributions to vertical lift from the aircraft's wings and rotor thrust). If the misalignment is significant, the adjustments may be made more abruptly as appropriate, based on safety margins and / or flight comfort considerations.

[0196] At block 616, a determination is made automatically (or optionally manually) as to whether the glide slope control mode should currently be exited (e.g., if the aircraft is in condition v H =0 and h= hoffset (e.g., when the aircraft reaches the glide slope offset). Otherwise, the flowchart proceeds to block 610. On the other hand, if the condition is met, the flowchart proceeds to block 618, where the landing is completed. For example, when the minimum altitude of the glide slope (i.e., hoffset) is reached, the aircraft's flight control system automatically transitions to "hover mode." In hover mode, altitude relative to the ground is maintained (rate of descent ROC = 0) and altitude does not change unless commanded by the pilot. Additionally, the pilot can move the aircraft laterally (left / right, and optionally forward / backward) to fine-tune the precise landing point.

[0197] At block 620, after landing is complete, the flow chart ends.

[0198] Flight control system compatible with glide slope control mode 6 is a schematic diagram illustrating a flight control system 650 for vertical landing aircraft 1 according to some embodiments of the present disclosure. While flight control system 650 components specifically related to glide slope control are highlighted, landing control system 650 provides functionality for controlling the overall flight of aircraft 1.

[0199] Flight computer 651, in some embodiments, includes a computer processor and memory, where the computer processor executes instructions to control the flight characteristics of aircraft 1. Components of aircraft 1 other than landing control system 650 are described herein, for example, with respect to Figures 2A and 2C.

[0200] Flight computer 651 determines the current flight state of the aircraft based on an appropriate combination of data received from position / velocity sensors 652, other aircraft state sensors / actuators 654, motors 656, and / or map data 657. Position / velocity detection (including altitude and aircraft attitude detection, e.g., pitch, yaw / heading, and / or roll) may be performed using any suitable technology or combination thereof, such as GPS, radio beacons, inertial tracking, magnetic compass, barometric pressure, pitot tubes, and / or MEMS. Aircraft state sensors may provide information regarding, for example, temperature, remaining battery charge, flight time, cabin pressure, equipment operating status, or any other data generally related to aircraft function. In particular, motors 656 may provide information regarding current torque and / or rotational speed as an indicator of thrust and / or performance. In some embodiments, map data 657 is used to contextualize sensor data, for example, to determine current absolute altitude or to predict altitude along the current or predicted route. The "Actuators" portion (optional in some embodiments) of aircraft state sensors / actuators 654 optionally provides information regarding the position of the aircraft's actuators, for example, the position of movable flight control surfaces, if applicable.

[0201] In some embodiments, the memory of flight computer 651 contains target state information 659, which computer 651 uses to determine whether and, if so, what adjustments are needed to the operation of motors 656 and / or actuators of aircraft state sensors / actuators 654. Part of the target state information 659 are pre-defined parameters that define how to respond to various data patterns to achieve proper flight in a particular flight mode. For example, this information may describe how to change pitch and thrust from current (controllable) state conditions to progress to a new (flight) state, as dictated by pilot input. Target state information 659 is also partly defined by pilot input 660, which instructs the flight computer on what the pilot wants to do. This input may take the form of, for example, autopilot settings, map selection, flight mode settings, and / or sequential inputs from a flight controller (e.g., joystick). The target state information 659 may also describe flight mode switching conditions, such as switching from cruise flight to glide slope control mode for landing approach, and from glide slope control mode to hover descent mode during the final stages of landing.

[0202] During glide slope control mode (flying along a path specified in part based on the glide slope upon approach to landing site 3), in some embodiments, pilot inputs 660 include a glide slope input 662. This glide slope input 662 is provided, for example, by a motion axis of flight controller 505 (as described in connection with FIG. 2C ) and allows adjustment of the glide slope. Optionally, the descent deceleration profile is modulated by a deceleration modulation input 664, which is optionally mapped to an active control axis (e.g., a trigger used as a throttle input, or more generally, an airspeed selection input). Additionally or alternatively, the descent deceleration profile is set as a permanent parameter (e.g., mode selection). Optionally, the deceleration profile is fixed, for example, a linear deceleration suitable for reaching the target landing site at an offset position on the ground is selected. Deceleration profiles are described, for example, in connection with FIGS. 3A-3B . The pilot typically also controls other inputs 666 as appropriate. For example, yaw and / or heading are typically controlled by flight controller 505. Other inputs 666 optionally include, for example, map selection and other navigation inputs, mode selection, and / or parameters that control how flight computer 651 selects among flight control options (e.g., sensitivity and / or steepness of response).

[0203] General As used herein, the term "about" when used in connection with an amount or value means "within ±10%."

[0204] The words "comprises," "comprising," "includes," "including," "having," and combinations thereof mean "including, but not limited to."

[0205] The term "consisting of" means "including and limited to."

[0206] The term "consisting essentially of" means that a composition, method, or structure may include additional ingredients, steps, and / or components, provided that the additional ingredients, steps, and / or components do not materially alter the basic and novel characteristics of the claimed composition, method, or structure.

[0207] As used herein, the singular forms "a," "an," and "the" are intended to include the plural unless the context clearly requires otherwise. For example, the terms "a compound" or "at least one compound" include a plurality of compounds, and may also include mixtures thereof.

[0208] As used herein, the words "example" and "exemplary" mean "serving as an example, instance, or illustration." Any embodiment described as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments, and does not exclude the incorporation of features of other embodiments.

[0209] As used herein, the term "optionally" means "provided in some embodiments and not provided in other embodiments." Particular embodiments of the present disclosure may include multiple "optional" features, unless they are mutually inconsistent.

[0210] Throughout this specification, embodiments may be presented in range format. Descriptions in range format are for convenience and brevity and should not be construed as strictly limiting the scope of the description of the present disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all possible subranges and individual numerical values ​​within that range. For example, describing a range "from 1 to 6" is considered to have specifically disclosed subranges such as "from 1 to 3," "from 1 to 4," "from 1 to 5," "from 2 to 4," "from 2 to 6," "from 3 to 6," and individual numerical values ​​within that range, e.g., 1, 2, 3, 4, 5, and 6. This applies regardless of whether the range is broad or narrow.

[0211] When numerical ranges are given herein (e.g., "10-15," "10 to 15," or any combination of numbers joined by other range expressions), they are intended to include the limits of the range and all numbers (both fractional and integer) within the range, unless the context clearly requires otherwise. In addition, the terms "range / ranging / ranges between," "range / ranging / ranges from," and expressions using "to," "up to," "until," "through," or other range terms are used interchangeably and are intended to include the first and second numerical values ​​and all fractional and integer values ​​therebetween.

[0212] While the description of this disclosure has been provided in conjunction with specific embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the claims appended hereto.

[0213] It is understood that certain features that are, for clarity, described in the context of separate embodiments in this disclosure may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable subcombination or compatible with any other embodiment of the present disclosure. Furthermore, certain features described in the context of various embodiments are not to be construed as essential features unless the embodiment cannot function without those elements.

[0214] It is the applicant's intention that all publications, patents, and patent applications mentioned herein be incorporated by reference in their entireties to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated herein by reference. Furthermore, the identification of any citation or reference in this application should not be construed as an admission that the reference is available as prior art to the present disclosure. Furthermore, section headings, if used, should not be construed as necessarily limiting. Additionally, any priority document claimed in this application is incorporated herein by reference in its entirety.

Claims

1. 1. A method for automatically controlling forward and descent rates of an aircraft as the aircraft descends to a landing site, comprising: adjusting the target glideslope of the aircraft in accordance with updated instructions by the pilot for corrections to the target glideslope; automatically adjusting the ratio of the speeds as the target glide slope is adjusted so that the aircraft descends along the target glide slope; automatically reducing the forward speed from a starting speed to a finishing speed while maintaining the ratio of the speeds to correspond to the desired glide slope; The method, wherein the starting velocity and the ending velocity differ by at least half the starting velocity of the aircraft.

2. The method of claim 1 , wherein the ending speed is less than 10% of the starting speed of the aircraft.

3. The method of claim 2 , wherein the end velocity is a stationary velocity.

4. 3. The method of claim 1, wherein the starting speed is at least 80% of the design cruise speed of the aircraft.

5. 5. The method of claim 1, further comprising: landing the aircraft at the landing site, wherein the terminal velocity is reached when the aircraft is positioned over the landing site.

6. 5. The method of claim 1, wherein the aircraft decelerates from the starting speed to the ending speed while descending from a starting altitude to an ending altitude, and the ratio of the starting altitude to the ending altitude is within three times the ratio of the starting speed to the ending speed.

7. 7. The method of claim 6, wherein the forward speed decreases approximately linearly as a function of altitude for at least half the range of the difference between the starting altitude and the ending altitude.

8. A method according to any one of claims 6 to 7, wherein the reduction in forward speed as a function of altitude comprises a deceleration that increases for at least 10% of the difference between the starting altitude and the ending altitude.

9. 9. The method of claim 6 or 8, wherein the reduction in forward speed as a function of altitude comprises a deceleration rate that decreases for at least 10% of the difference between the starting altitude and the ending altitude.

10. 8. A method according to claim 6 or 7, wherein the forward speed decreases, on average, linearly as a function of altitude for at least 90% of the difference between the starting altitude and the ending altitude.

11. 11. The method of any one of claims 6 to 10, wherein the end altitude is within 2 meters vertically of the landing point.

12. The method of claim 10 , wherein the end altitude is within 0.5 meters vertically of the landing point.

13. 13. The method of claim 11 or 12, wherein the terminal velocity is less than 2 m / s.

14. The method of claim 13 , wherein the end velocity is a stationary velocity.

15. A method according to any one of claims 7 to 14, wherein the final altitude and final velocity are reached at a position above the landing site.

16. 16. The method of claim 15, comprising hovering the aircraft in a position above the landing site.

17. The update instructions for the modification include: a first stage in which the correction changes the target glide slope so that the aircraft descending along the target glide slope points toward the landing site; a second step, after the first step, of causing the aircraft to descend along the target glide slope while keeping the trajectory of the aircraft pointed toward the landing site by the correction.

18. The update instructions for the modification include: a first stage in which the correction changes the target glide slope such that the aircraft's descent path along the target glide slope is directed away from the landing site; and a second step of adjusting the trajectory of the aircraft toward the landing site along an adjusted target glideslope using the correction.

19. A method according to any preceding claim, wherein the pilot communicates the correction update instruction by adjusting an axis of a flight controller.

20. When the terminal velocity is reached, ceasing to adjust the rate of speeds to accommodate a descent of the aircraft along the desired glide slope; and using an axis of the flight controller to command a desired flight parameter other than the glide slope.

21. 21. The method of claim 20, wherein the target flight parameters include movement of the aircraft along only one of a vertical altitude and a direction orthogonal to the vertical altitude.

22. 22. The method of any one of claims 1 to 21, wherein after reaching the terminal speed, the aircraft continues flying but without adjusting altitude based on the updated indication of the correction to the target glide slope.

23. 23. The method of any one of claims 1 to 22, wherein maintaining the ratio in response to the target glide slope causes the aircraft to move along a straight glide path with a forward descending motion and lateral movement of the aircraft to be constant during periods when the target glide slope remains unchanged.

24. 24. The method of any one of claims 1 to 23, wherein updating the correction and subsequently maintaining a speed ratio corresponding to the target glide slope generates a glide path that directs the aircraft toward a ground location that is closer or farther from the aircraft, depending on whether the correction commands a steeper or gentler target glide slope.

25. 25. The method of claim 1, wherein the updating of the correction and subsequent maintenance of a speed ratio corresponding to the target glide slope generates a glide path that descends toward the landing site at a relatively high descent rate with the same forward speed for a relatively steep target glide slope.

26. 26. The method of any one of claims 1 to 25, wherein the correction update instructions are determined by the pilot based on the pilot's direct visual observation of the landing site at an angle greater than or equal to 10 degrees downward from horizontal.

27. 27. The method of claim 26, wherein the correction update instructions are determined by the pilot based on the pilot's direct visual observation of the landing site at an angle greater than 30 degrees below horizontal.

28. 28. A method according to claim 26 or 27, wherein the pilot's direct view of the landing site is through a window located in the aircraft below the pilot's waist.

29. 29. A method according to any one of claims 26 to 28, wherein the pilot has a direct view of the landing site through a window located adjacent to a footrest from the pilot's perspective.

30. 26. A method according to any preceding claim, wherein the correction update instructions are determined by the pilot based on a camera view of the landing site at an angle of 30 degrees or more below horizontal.

31. It has a processor and memory, The memory, to the processor, adjusting the target glideslope of the aircraft in accordance with updated instructions by the pilot for corrections to the target glideslope; automatically adjusting a ratio of forward speed to descent speed as the target glide slope is adjusted so that the aircraft descends along the target glide slope; automatically reducing the forward speed from a starting speed to a finishing speed while maintaining the ratio to correspond to the desired glide slope; and instructions to execute The difference between the initial speed and the final speed is at least half of the initial speed. Vertical landing aircraft flight control system.

32. 32. A flight control system as described in claim 31, comprising the aircraft.

33. 33. A flight control system as described in claim 31 or 32, wherein the end speed is a static speed and the start speed is at least 80% of a design cruise speed of the aircraft.

34. 34. A flight control system as described in any one of claims 31 to 33, wherein the aircraft decelerates from the starting speed to the ending speed while descending from a starting altitude to an ending altitude, and the ratio of the starting altitude to the ending altitude is within three times the ratio of the starting speed to the ending speed.

35. 35. The flight control system of claim 34, wherein the terminal altitude and terminal speed are reached at a location over the landing site where the flight control system maintains the aircraft in a hover.

36. a downward view out of the aircraft through a window located forward adjacent to a footrest for the pilot's feet; identifying a landing site visible below through said forwardly disposed window; approaching the landing site at a forward speed that is a static speed while reducing speed and altitude until the aircraft lands at the landing site; How a pilot lands an aircraft.

37. 37. The method of claim 36, wherein the approach is performed while maintaining forward and descending speeds at rates that establish a glide slope that directs the aircraft toward the landing site.

38. 38. The method of claim 36 or 37, wherein the approaching is performed while reducing forward speed as vertical distance to the landing site decreases.

39. a lower-forwardly located window having an area that is located below the waist of a pilot seated upright during horizontal forward flight of the aircraft; and lighting positioned to project one or more target designations into the pilot's field of view using the window as a reflective surface.

40. Providing a first sequence of flight direction commands to the aircraft by moving the flight controller along an axis; and providing a second sequence of flight directions to the aircraft by moving the flight controller along the same axis, the first sequence of flight direction commands controls a glide slope setting used to determine a glide path for the aircraft; The second sequence of flight direction instructions comprises: horizontal movement of said aircraft without vertical movement; vertical movement of the aircraft without horizontal movement; pitch, which does not involve horizontal or vertical movement of the aircraft; A method for controlling any one selected from the group consisting of:

41. a computerized flight control system that performs enhanced flight modes for the aircraft; 1. A vertical landing aircraft, wherein said computer-controlled flight control system reduces said forward speed and vertical speed of said aircraft to a static landing speed as a function of altitude above the ground while maintaining a fixed ratio between said forward speed and vertical speed.

42. 42. An aircraft as claimed in claim 41, comprising a transparent window facing the ground from the perspective of a pilot seated upright, for viewing during descent and speed reduction the landing area that will be reached when static speed is reached.

43. A camera pointing downwards towards the ground, a display for displaying to a pilot of the aircraft; 42. An aircraft according to claim 41, wherein via said display the landing area that will be reached when a stationary speed is reached is viewed during descent and speed reduction.

44. A computer-controlled flight control system configured to maintain a fixed ratio between forward and vertical speeds of an aircraft while reducing said forward and vertical speeds to a static landing speed as a function of altitude above the ground.

45. 45. The computer controlled flight control system of claim 44, wherein in hover mode, the static landing speed is reached when the forward speed is zero and the altitude is near zero.

46. 46. ​​A computer controlled flight control system as described in claim 44 or 45, wherein the fixed ratio selects the location of a target landing area, and the fixed ratio is selected based on control stick movement adjustments.

47. 47. The computer controlled flight control system of claim 46, wherein the target landing area is adjusted by altering a descent angle in response to movement of the control stick, the alteration including replacing the fixed ratio with a ratio corresponding to the altered descent angle.

48. 48. The computer controlled flight control system of claim 47, wherein the flight control system adjusts the target landing area by varying the rate of descent and / or forward speed deceleration in response to the replaced fixed ratio.

49. A method for vertical landing of an aircraft, automatically maintaining a fixed ratio between forward and vertical speeds of the aircraft while reducing said forward and vertical speeds to a static landing speed as a function of altitude above the ground.

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