Unmanned aircraft and its use

Abstract

An unmanned aircraft (2) has an aerodynamically shaped fuselage (5) stretched along a main axis (6), aerodynamically effective surfaces (7) projecting from the fuselage (5) transversely to the main axis (6), and a thrust generating device for generating thrust along the main axis (6). When the aircraft (2) is gliding (3) along the main axis (6), the aerodynamically effective surfaces (7) are adjustable for steering the aircraft. The thrust generating device has at least three thrust generators (10) which can be moved out of the fuselage (5) into working positions distributed around the main axis (6) in the circumferential direction relative to one another. In their working positions, which can be controlled to fly the aircraft (2) in a hover (4) with the main axis (6) aligned vertically.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to an unmanned aircraft having an aerodynamically shaped fuselage elongated along a main axis, aerodynamically effective surfaces projecting from the fuselage transversely to the main axis, and a thrust generating device for generating thrust along the main axis. The aerodynamically effective surfaces are adjustable along the main axis for steering the aircraft during gliding flight. The thrust generating device comprises at least three thrust generators. Furthermore, the invention relates to a use of such an unmanned aircraft. STATE OF THE ART

[0002] Among the most well-known unmanned aerial vehicles, also known as drones, are so-called quadrocopters and other multicopters. A multicopter has several propellers driven around spaced, vertically aligned axes of rotation. The propellers are often powered by electric motors. Multicopters are steered by controlling the propeller drives in different ways. The maximum flight time of multicopters with electric motors is limited by the capacity of the on-board electrical energy storage device when the multicopter is flying freely and is not connected to a ground station via a power cable. Typical maximum flight times for multicopters with electric motors are less than one hour. This limits the range of multicopters.Multicopters achieve high horizontal flight speeds when the rotational axes of their propellers are tilted at an angle of more than 60° relative to the vertical.

[0003] Multicopters hover. They can hover and be flown in any direction. They are therefore also suitable for flying inside winding buildings, for example, for exploring them. Multicopters are often equipped with camera systems and other sensor systems that can be used for this exploration. Multicopters are also known to use their sensor systems for autonomous flight in enclosed spaces.

[0004] In addition to multicopters, drones are also known that fly on the principle of fixed-wing aircraft. While such drones have a greater range than multicopters with comparable energy storage capacity for powering electric motors, they are neither suitable for hovering nor for use in enclosed buildings.

[0005] An unmanned aircraft with an aerodynamically shaped fuselage stretched along a main axis, with aerodynamically effective surfaces projecting from the fuselage transversely to the main axis, and with a thrust-generating device for generating thrust along the main axis. The aerodynamically effective surfaces can be adjusted along the main axis for steering the aircraft during gliding flight. This is a so-called propelled glide bomb. A glide bomb is released by a parent aircraft not only at a vertical but also a horizontal distance from a target to be bombed, or is launched into such a position. It then glides to its target, being steerable by adjusting its aerodynamically effective surfaces.The glide of a glide bomb can be a purely passive glide, in which the glide bomb's horizontal acceleration is achieved solely through the loss of potential energy. Known self-propelled glide bombs typically have a jet engine mounted along the main axis of their fuselage. The aerodynamically effective surfaces of a glide bomb are often at least partially foldable, so that the glide bomb requires less storage space with its aerodynamically effective surfaces still folded in, and can be placed, for example, in the tube of a rocket launcher.

[0006] An unmanned aircraft with the features mentioned above, which correspond to the preamble of independent patent claim 1, is known from WO 2020 / 183594 A1. This is a so-called tailsitter, which has four main wings rigidly attached to a fuselage in an X-shaped configuration when viewed from the front, and eight propellers, two at a time, attached to each of the main wings with a fixed orientation to the main wing. With the propellers, the aircraft can take off vertically from a takeoff position with the fuselage vertically aligned, in which it sits on its tail as a tailsitter, and generate thrust in flight with the fuselage horizontally aligned. OBJECT OF THE INVENTION

[0007] The invention is based on the object of demonstrating an unmanned aerial vehicle which has a long range despite being capable of hovering. SOLUTION

[0008] The object of the invention is achieved by an unmanned aircraft having the feature of independent claim 1. The dependent claims relate to preferred embodiments of the aircraft according to the invention and its preferred use. DESCRIPTION OF THE INVENTION

[0009] An unmanned aircraft according to the invention having an aerodynamically designed fuselage stretched in the direction of a main axis, having aerodynamically effective surfaces projecting from the fuselage transversely to the main axis and having a thrust generating device for generating thrust along the main axis, wherein the aerodynamically effective surfaces are adjustable along the main axis in gliding flight of the aircraft for steering the aircraft, is characterized according to the invention in that the thrust generating device has at least three thrust generators which can be moved out of the fuselage into working positions distributed around the main axis in the circumferential direction relative to one another and can be controlled to fly the aircraft in hover with the main axis aligned vertically.In this way, the aircraft according to the invention is suitable for both hovering and gliding and therefore has a long range compared to other unmanned aircraft suitable for hovering, in particular when using electric drives for the thrust generators.

[0010] The fact that the fuselage of the aircraft according to the invention is elongated means that it has an extension in the direction of its main axis that is at least 1.5 times as large, regularly at least 2 times as large, and often at least 2.5 times as large as its maximum diameter. The fuselage of the aircraft according to the invention is aerodynamically designed to have low flow resistance and a small radar signature when gliding along its main axis. The aerodynamically effective surfaces of the aircraft can be formed at least partially on wings that protrude from the fuselage perpendicularly or at an angle other than 90° to the main axis. The at least three thrust generators of the thrust generation device of the aircraft according to the invention can be moved linearly out of the fuselage into their operating positions or in any other movement, in particular a pivoting movement.The operating positions of the thrust generators can be identical to each other circumferentially around the main axis. In any case, a symmetrical arrangement of the thrust generators is preferred. In hovering with a vertically aligned main axis, the thrusts of all thrust generators must be coordinated to prevent the fuselage from tilting, which would lead to an uncontrolled loss of the vertical orientation of its main axis. Conversely, for the aircraft to hover in a specific direction, the main axis must be tilted in a controlled manner in that direction.

[0011] During gliding flight of the aircraft according to the invention, the thrust generators are preferably not only located in its fuselage but are also inactive. For gliding flight, the aircraft according to the invention then uses only its potential energy due to its altitude above the ground, which it achieves with a manned or unmanned parent aircraft or by launching from the ground. To transition from gliding to hovering, the thrust generators must be extended from the fuselage, and the main axis of the fuselage must be aligned vertically. The latter can be achieved at the end of the gliding flight by changing direction using the aerodynamically effective surfaces and, optionally, with the assistance of the thrust generators.

[0012] The thrust generators of the aircraft according to the invention can each have a propeller and an electric motor. Accordingly, the aircraft according to the invention can include a storage unit for electrical energy to supply the electric motors. The capacity of this storage unit limits, in particular, the flight time or the range of the aircraft according to the invention during hovering. During gliding flight, the storage unit is not used except for controlling the aircraft and adjusting its aerodynamically effective surfaces.

[0013] Specifically, the thrust generators can be mounted at the free ends of pivot arms that can be pivoted out from the fuselage. The pivot arms can each carry two thrust generators, which are mounted on the pivot arms in such a way that, after pivoting out or during the pivoting out of the pivot arms, they move apart in the circumferential direction into their working positions. In one embodiment, the aircraft according to the invention has two such pivot arms, each with two thrust generators, which are arranged symmetrically to one another. The pivot arms can be pivoted out using electric motor actuators. The pivot arms are preferably actuated by preloaded spring-loaded devices for pivoting out, so that they only need to be released to pivot out.

[0014] At least some of the aerodynamically effective surfaces of the aircraft according to the invention can be extendable out of the fuselage and / or retractable into the fuselage. Spring-loaded mechanisms can also be used for this purpose. The aerodynamically effective surfaces can be extended after the aircraft according to the invention has been deployed for gliding flight. The aerodynamically effective surfaces can be retracted for hovering flight, also to reduce the dimensions of the aircraft and thus the risk of collisions.

[0015] Extending or re-extending individual or all aerodynamically effective surfaces can also be useful for fast horizontal flight of the aircraft according to the invention. Thus, at least some of the aerodynamically effective surfaces can be configured to generate lift in fast horizontal flight with the thrust generators moved into their working positions and activated, and with the main axis inclined by at least 30° relative to the vertical. These aerodynamically effective surfaces can thus reduce the energy requirement of the thrust generators by at least 30%, preferably at least 45%, and even more preferably at least 60%, compared to hovering flight without aerodynamically effective surfaces projecting from the fuselage and at least substantially stationary relative to the fuselage.During such rapid horizontal flight, the inclination angle of the main axis relative to the vertical can be at least 45° and even at least 60°, and in extreme cases, approach 90°. With rapid horizontal flight, the aircraft according to the invention has another means of propulsion that requires less energy than hovering.

[0016] The aerodynamically effective surfaces can be moved out of or into the fuselage in the form of swivel movements.

[0017] At a rear end of the fuselage of the aircraft according to the invention along the main axis, a landing gear can be formed, which comprises trailing edges of the aerodynamically effective surfaces. With this landing gear, the aircraft according to the invention can touch down on the ground with the main axis aligned vertically.

[0018] The aircraft according to the invention preferably has a camera system which completely images an environment of the aircraft or with which an environment of the aircraft can at least be completely imaged by pivoting one or more cameras of the camera system relative to the fuselage of the aircraft.

[0019] Furthermore, the aircraft according to the invention preferably has an integrated controller configured for autonomous flight of the aircraft. In particular, the controller allows the aircraft to hover in confined spaces, such as the interiors of buildings.

[0020] When using an aircraft according to the invention, the aircraft is flown in gliding flight to a target area and then hovered in the target area. The thrust generators are arranged in the fuselage of the aircraft during gliding flight. Furthermore, the thrust generators are generally inactive during gliding flight.

[0021] From the target area, the aircraft according to the invention can be flown in a fast horizontal flight. Outside the target area, the aircraft according to the invention can be landed on its landing gear with its main axis aligned vertically. Before gliding, the aircraft according to the invention can be released from a parent aircraft with its main axis aligned horizontally, at a location both horizontally and vertically distant from the target area. Alternatively, the aircraft according to the invention can be launched from the ground into a position elevated relative to the target area, from which it then reaches the target area by gliding.

[0022] It is understood that the aircraft according to the invention can be connected to a base station via a wireless data communication link to transmit the images from its camera system. However, the aircraft according to the invention can also operate deliberately without such a data communication link detectable by third parties and initially store the image data recorded by its camera system in order to be able to read them after the aircraft returns from the target area.

[0023] A particular advantage of the aircraft according to the invention is that it can be designed for particularly quiet gliding flight, in which neither the thrust generators contribute to the noise generation nor to the radar signature of the aircraft.

[0024] When swung out, the pivot arms with the thrust generators can extend from the fuselage in the direction of the main axis at the height of the aircraft's center of gravity, perpendicular to the main axis. The aircraft's center of gravity can also be located below the thrust generators when hovering. Placing the center of gravity above the thrust generators is also possible in principle, but less stable.

[0025] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0026] The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be effective alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0027] With regard to the disclosure content – ​​not the scope of protection – of the original application documents and the patent, the following applies: Further features can be found in the drawings – in particular the illustrated geometries and the relative dimensions of several components to one another, as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or features of different patent claims is also possible, deviating from the chosen references of the patent claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features of different patent claims.Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

[0028] The number of features mentioned in the patent claims and the description is to be understood as meaning that exactly this number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least." For example, if reference is made to a spring-loaded mechanism, this is to be understood as meaning that exactly one spring-loaded mechanism, two spring-loaded mechanisms, or more spring-loaded mechanisms are present. The features mentioned in the patent claims may be supplemented by further features or may be the only features present in the subject matter of the respective patent claim.

[0029] The reference signs contained in the patent claims do not represent a limitation of the scope of the subject-matter protected by the patent claims. They serve solely to make the patent claims easier to understand. BRIEF DESCRIPTION OF THE CHARACTERS

[0030] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. Figure 1 shows schematically the transition of an aircraft according to the invention from its gliding flight to its hovering flight. Fig. 2 is an enlarged side view of an aircraft according to the invention in hovering flight. Fig. 3 shows the aircraft according to the invention according to Fig. 2 in a view from above; and Fig. 4 schematically shows a fast horizontal flight of the aircraft according to the invention from a target area to a ground station. FIGURE DESCRIPTION

[0031] Fig. 1 shows a mother aircraft 1, with which an unmanned aircraft 2 is deployed. The unmanned aircraft 2 is in Fig. 1 in various stages of a gliding flight 3 and a transition to a hovering flight 4. The aircraft 2 is shown enlarged in the Fig. 2 and Fig. 3 in its hover 4. The aircraft 2 has a fuselage 5 which is stretched in the direction of a main axis 6. Here, a length of the fuselage 5 in the direction of the main axis 6 is slightly more than twice as large as a maximum diameter of the fuselage 5 transverse to the main axis 6. From the fuselage 5, at a rear end of the fuselage 5 in the direction of the main axis 6, which in the hover 4 according to the Fig. 2 and Fig. 3 points downwards, aerodynamically effective surfaces 7 transverse to the main axis 6. The aerodynamically effective surfaces 7 are adjustable in order to guide the aircraft 2 in its gliding flight 3 according to Fig. 1. The aerodynamically effective surfaces 7 are divided into fixed wings 23 and rudders 24 that can be adjusted relative to the wings. Trailing edges 8 of the aerodynamically effective surfaces 7 form parts of a landing gear 9 of the aircraft at its rear end. In addition to the aerodynamically effective surfaces 7 at the rear end of the aircraft 2, further, even larger, aerodynamically effective surfaces can protrude from the fuselage 5 of the aircraft 2 permanently or only during one of its flight conditions. In the hover 4 according to the Fig. 2 and Fig. 3, thrust generators 10, which generate thrust in the direction of the main axis 6, are arranged distributed circumferentially around the main axis 6 around the fuselage 5. Specifically, the thrust generators 10 are four propellers 11 and 12 with electric motors 13, which are arranged in a quadrocopter configuration. In each case, a pair of propellers 11 and 12 is pivoted out of the fuselage 5 on a pivot arm 14; and opposite the free end of the respective pivot arm 14, the propellers 11 and 12 are moved apart in the circumferential direction around the main axis 6. Thus, the propellers 11 and 12 generated in gliding flight 3 according to Fig. 1 thrust generators 10 arranged within the fuselage 5 have been transferred into their working positions for hovering 4. The propellers 11 rotate about their rotation axes 15 in rotation planes below the free ends of the pivot arms, and the propellers 12 rotate about their rotation axes 16 in rotation planes above the free ends of the pivot arms 14, so that a collision of the propellers 11 and 12 is excluded even before they move apart in the circumferential direction about the main axis 6. Rather, the rotation of the propellers 11 and 12 about their rotation axes 15 and 16 can cause the thrust generators 10 to move apart in the circumferential direction about the vertical axis 6. Fig. The camera system 17 of the aircraft 2, which is schematically indicated in FIG. 2, is designed in such a way that it enables a panoramic view of the surroundings of the aircraft 2 and thus a complete orientation of the aircraft 2 in this surroundings. Fig. 1 shows that the aircraft 2 is released from the parent aircraft 1 with its main axis 6 aligned horizontally and then initially flies in a gliding flight 3 with a slightly inclined main axis 6 to a target area 18 on the ground 19. Upon approaching the target area 18 or in the target area 18, the aircraft 2 enters its hovering flight 4. For this purpose, the main axis 6 is aligned vertically; and the swivel arms 14 with the thrust generators 10 are swiveled out. The raising of the main axis 6 to the vertical can occur essentially or solely with the aid of the aerodynamically effective surfaces 7 or already with the assistance of the thrust generators 10. In the target area 18, the aircraft 2 can penetrate buildings in a hovering flight or fly between buildings to explore them.

[0032] Fig.4 illustrates the return flight of the aircraft 2 from the target area 18 to a ground station 20 in a fast and at least substantially horizontal horizontal flight 21. In this fast horizontal flight 21, the main axis 6 of the aircraft 2 is inclined in the direction of flight. The aircraft 2 is propelled by the thrust generators 10 at the free ends of the pivot arms 14, with the aerodynamically effective surfaces 7 generating lift, which reduces the energy requirement of the thrust generators 10. At the ground station 20, the aircraft 2 touches down on a landing surface 22 with its landing gear 9 and the main axis 6 aligned vertically. The fuselage 5 is aerodynamically designed for low air resistance in the gliding flight 3 and in particular in the fast horizontal flight 21.

[0033] The aircraft 2 shown in the figures can be dimensioned as follows: The flight weight is between 2 kg and 10 kg, for example, around 5 kg. With a flight weight of 5 kg, a speed of 200 km / h and a total area of ​​the aerodynamically effective surfaces 7 of 0.2 m 2 distributed over 4 aerodynamically effective surfaces 7, this results in an approximate surface loading of the aerodynamically effective surfaces 7 acting as a wing in gliding flight of 50 kg / m 2 Depending on the agility, the area of ​​the rudder should be approximately 10% of the chord width and 30% of the width of the aerodynamically effective surfaces 7. LIST OF REFERENCE SYMBOLS 1 mother aircraft 2 aircraft 3 Gliding 4 Hover 5 Hull 6 Main axis 7 aerodynamically effective area 8 trailing edge 9 Landing gear 10 thrust generator 11 propellers 12 propellers 13 Electric motor 14 Swivel arm 15 Rotation axis 16 Rotation axis 17 Camera system 18 Target area 19 Floor 20 ground station 21 fast forward flight 22 landing area 23 wings 24 oars

Claims

[1] Unmanned aerial vehicle (2) with - an aerodynamically shaped fuselage (5) stretched in the direction of a main axis (6), - aerodynamically effective surfaces (7) projecting transversely to the main axis (6) from the fuselage (5) and - a thrust generating device for generating thrust along the main axis (6), - wherein the aerodynamically effective surfaces (7) are adjustable in a gliding flight (3) of the aircraft (2) along the main axis (6) for steering the aircraft, - wherein the thrust generating device comprises at least three thrust generators (10), characterized by that the thrust generators (10) - can be moved out of the fuselage (5) into working positions distributed around the fuselage (5) in the circumferential direction around the main axis (6) and - in their working positions, they can be controlled to fly the aircraft (2) in hover (4) with the main axis (6) aligned vertically. [2] Aircraft (2) according to claim 1, characterized by that the thrust generators (10) each have a propeller (11, 12) and an electric motor (13). [3] Aircraft (2) according to claim 1 or 2, characterized by that the thrust generators (10) are mounted on the free ends of swivel arms (14) which can be pivoted out of the fuselage (5). [4] Aircraft (2) according to claim 3, characterized by that two thrust generators (10) are mounted on each of the pivot arms (14) in such a way that, after the thrust arms (14) have been pivoted out, they move apart in the circumferential direction around the main axis (6) into their working positions. [5] Aircraft (2) according to claim 3 or 4, characterized by that the pivot arms (14) are loaded with pre-tensioned spring accumulators for pivoting out. [6] Aircraft (2) according to one of the preceding claims, characterized bythat at least some of the aerodynamically effective surfaces (7) can be extended out of the fuselage (5) and / or retracted into the fuselage (5), wherein the aerodynamically effective surfaces (7) can optionally be pivoted relative to the fuselage (5). [7] Aircraft (2) according to one of the preceding claims, characterized by that a landing gear (9) is formed at a rear end of the fuselage (5) in the direction of the main axis (6), which comprises trailing edges (8) of the aerodynamically effective surfaces (7). [8] Aircraft (2) according to one of the preceding claims, characterized by that an environment of the aircraft (2) can be completely imaged using a camera system (17) of the aircraft (2). [9] Aircraft (2) according to one of the preceding claims, characterized by that an integrated control of the aircraft (2) is designed for autonomous flying of the aircraft (2). [10] Aircraft (2) according to one of the preceding claims, characterized by that at least some of the aerodynamically effective surfaces (7) for generating lift in a fast horizontal flight (21) are designed with thrust generators (10) moved into their working positions and active and with a main axis (6) inclined by at least 30 °, preferably at least 45 ° and more preferably at least 60 ° with respect to the vertical, wherein the aerodynamically effective surfaces (7) reduce the energy requirement of the thrust generators (10) by at least 30 %, preferably at least 45 % and more preferably at least 60 %. [11] Use of an aircraft (2) according to one of the preceding claims, wherein the aircraft (2) is flown in the gliding flight (3) into a target area (18) and is flown in the hovering flight (4) in the target area (18), wherein the thrust generators (10) are arranged in the fuselage (5) in the gliding flight. [12] Use according to claim 11 of the aircraft (2) according to claim 10, characterized by that the aircraft (2) is flown out of the target area (18) in the fast horizontal flight (21). [13] Use according to claim 11 or 12 of the aircraft (2) according to claim 7, characterized by that the aircraft (2) is landed on its landing gear (9) with its main axis (6) aligned vertically. [14] Use according to any one of claims 11 to 13, characterized by that the aircraft (2) is deployed away from the target area (18) with its main axis (6) aligned horizontally by a mother aircraft (1). [15] Use according to any one of claims 11 to 14, characterized by that the main axis (6) is aligned vertically before, during or after the movement of the thrust generators (10) into their working positions.

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