CN116374157A - Aeronautical drive, aircraft and method for operating aeronautical drive - Google Patents

Abstract

The invention relates to an aeronautical drive (3) for an aircraft (1), comprising: -a propeller (4) which is arranged on a drive shaft (5) of the aero-drive device (3) and which can be driven by means of the drive shaft (5) around a rotational axis (6) of the propeller (4), -a propeller fairing (8) which is arranged in a front region (10) of the propeller (4) viewed in a direction (9) of the rotational axis (6) of the aero-drive device (3), -a propeller fairing adjustment device (12) for changing the volume of the propeller fairing (8) in a defined manner in a radial direction (13) with respect to the rotational axis (6). The invention further relates to an aircraft (1) having at least one aeronautical drive (3) and to a method for operating an aeronautical drive (3).

Description

Aeronautical drive, aircraft and method for operating aeronautical drive

Technical Field

The invention relates to an aero-drive device for an aircraft, having a propeller which is arranged on a drive shaft of the aero-drive device and can be driven about a rotational axis of the propeller by means of the drive shaft. Furthermore, the aero drive has a propeller fairing which is arranged in a region of the propeller which is located at the front, viewed in the direction of the axis of rotation of the aero drive.

The invention further relates to an aircraft having at least one aeronautical drive. The invention also relates to a method for operating an aeronautical drive of an aircraft, wherein a propeller of the aeronautical drive, which is arranged on a drive shaft of the aircraft, is driven by the drive shaft about a rotational axis of the propeller.

Background

For example, the development of "personal air vehicles" (PAVs) or flying devices capable of taking off and landing vertically (evtols "electric vertical takeoff and landing aircraft") for future mobile solutions. This variant of the flying device can use a common propeller for both vertical take-off and cruise flight. For example, a "yaw wing scheme" or a "tiltrotor wing scheme" may be employed herein. Unlike the "lift and cruise solution", in these solutions a separate engine-propeller unit can be used both for take-off and for cruise flight (reifeplus), so that the mass of the flying device can be minimized.

The efficiency of the propeller has a significant influence on the stroke length of such a flying device, in particular on the electrical stroke length. However, for these solutions, the design of the propeller usually represents a compromise, since the design of the propeller must be adapted to both hover flight (hover or take-off process) and cruise flight. For example, variable pitch propellers are used in batches in classical aircraft. In the variable-pitch propeller, the individual propeller blades of the propeller rotate synchronously about their longitudinal axes and are thus adapted to the respective flight situation. Good efficiency can thus be achieved both during take-off (no incident flow speed is generated by the movement of the aircraft) and during cruising flight (incident flow speed is generated by the flight speed).

In the prior art, for example, variable propeller fairings (propulspiners) are known for targeted influencing of the cooling air flow for the internal combustion engine arranged downstream thereof, and in the prior art, propeller fairings optimized for aircraft with a "tiltrotor solution" are also disclosed.

The patent document US 2020/0 223 552a1 discloses, for example, a rotor arrangement for use in an aircraft. The rotor apparatus includes a rotor hub, a main shaft structure including a fairing opening, and rotor blades. The rotor blade has a rotor root located near the rotor hub. The rotor apparatus further includes a movable panel surface disposed at least partially along the rotor hub.

The disadvantage is that this represents a compromise which does not fully exploit the efficiency of the propeller, especially because the rotor blades rotate as a whole, but the flow conditions near the hub (small radius) and near the blade tip (large radius) are different. The variation of the engine speed and the angle of attack likewise offers only limited possibilities (degrees of freedom) to increase the efficiency.

Disclosure of Invention

The object of the invention is therefore to improve the efficiency of the aeronautical drive, in particular of the propeller.

The object is achieved according to the invention by an aeronautical drive for an aircraft, an aircraft and a method for operating an aeronautical drive for an aircraft.

One aspect of the invention relates to an aeronautical drive for an aircraft, the aeronautical drive having:

a propeller which is arranged on a drive shaft of an aeronautical drive and by means of which it can be driven about the axis of rotation of the propeller,

a propeller fairing arranged in a front region of the propeller, viewed in the direction of the axis of rotation of the aerodrive,

a propeller fairing adjustment device for changing the volume of the propeller fairing in a defined or defined manner in a radial direction with respect to the axis of rotation.

By means of the aeronautical drive according to the invention, for example, an aircraft or a flying device can be operated more efficiently. The efficiency of the propeller can be increased by changing the volume of the propeller fairing by definition by means of the propeller fairing adjustment. In this case, an efficiency increase of, for example, 10%, in particular 20%, in particular 25%, can be achieved compared to propellers of the prior art.

The travel length of the aircraft when cruising is performed can be increased by the aerodrive according to the invention. This is achieved by improved efficiency of the aeronautical drive. More loads ("Payload") may be sustained by more efficient aero-drive aircraft, for example. In particular, the aircraft load capacity can be increased by means of the aeronautical drive according to the invention while maintaining the stroke length unchanged.

In particular, a variable propeller fairing for an aircraft can be provided by means of a propeller fairing adjustment. It may occur, for example, with prior art propellers that, in cruising flight of an aircraft, local downward drives (Abtrieb) are achieved, for example, mainly in the vicinity of the hub of the propeller, instead of lift (propeller thrust). Thus, in the vicinity of the hub, the propeller blades for example tend to brake the flying device rather than drive the flying device. While averaging over, for example, the propeller radius still gives positive propeller thrust as lift, efficiency is lost. These disadvantages can be overcome, for example, by a defined change in the volume of the propeller fairing according to the invention, so that, for example, these disadvantageous regions in the vicinity of the hub can be isolated or covered. The efficiency of the propeller, in particular of the aeronautical drive, can thereby be increased. The propeller fairing may in particular be a propeller fairing, the size of which or the volume of which can be dynamically adjusted, which can be changed or varied by means of a propeller fairing adjustment device in such a way that, for example, areas of impaired efficiency of the propeller can be covered or isolated. The overall efficiency of the cruising flight of the aircraft can thereby be increased.

In particular, a defined change or adaptation (or adjustment) of the volume or diameter of the propeller fairing can be performed by means of the propeller fairing adjustment, as a result of which the efficiency of the aeronautical drive and the aircraft during cruising flight can be increased.

The aircraft may be, for example, a vertically-retractable aircraft, which may be referred to as an aircraft that can take off vertically and land vertically. The vertical takeoff and landing aircraft is particularly capable of changing flight modes (flight conditions) during flight. For example, hover flight in helicopter mode, followed by transition from vertical to horizontal flight and horizontal flight (corresponding to fixed wing aircraft) are considered relevant flight conditions for a vertically-lowerable aircraft.

The aero drive may be, for example, a tiltrotor (english). The aircraft may be designed, for example, as a deflected wing aircraft (english "tilt-wing aircraft").

The aircraft is in particular a "vertical take-off and landing aircraft" ("vertical take-off and landing aircraft", eVTOL). The aeronautical drive can thus be used for aircraft of this design. The aircraft may be, for example, an integral part of urban air traffic, such as an air taxi.

The aircraft is particularly capable of vertical take-off and vertical landing.

The propeller may in particular be an air propeller of an aircraft. The propeller can be used, for example, to generate the shaft power of an aircraft engine or the forward thrust or thrust of a shaft turbine.

The propeller may in particular be designed as a pitch-variable propeller, wherein the angle of attack of the propeller blades may be designed to be variable in the case of a pitch-variable propeller, whereby the angle of attack of the propeller blades can be adapted to different operating conditions of the aircraft. The propeller and the rotation shaft can be driven by means of the drive shaft, so that the propeller can be set at a preset rotation speed. The drive shaft may be configured parallel to the rotation axis, for example.

The propeller fairing may be a fairing for use in aviation, which fairing may be a streamlined panel of the aircraft in front of the propeller in the centre of the propulsion device, or may be a streamlined panel in a turbofan engine. Propeller fairings are used, for example, for reducing the air resistance and thus for improving the flow of propulsion devices of an aircraft.

The aeronautical drive may be referred to as a propulsion unit or propulsion unit of an aircraft, for example.

For example, the rotor head of the rotor can be covered at least in regions, in particular completely, by means of the rotor fairing. The propeller fairing can be, for example, a panel (cowling) of an aircraft engine or propulsion device. Such a panel of an aircraft engine may be referred to as a bonnet or a propulsion device cabin, for example.

In particular, the propeller fairing adjustment may be an electromechanical or a mechanical device. For example, the propeller fairing adjustment device can be actuated and/or controlled (regel) by means of a control and/or regulating device in order to change the volume of the propeller fairing. The change or adaptation or adjustment of the volume of the propeller fairing is achieved in particular automatically.

The change in volume is achieved in particular in dependence on the flight attitude (flugstillung) of the aeronautical drive or of the aircraft.

Alternatively, the propeller fairing may be radially enlarged by means of a propeller fairing adjustment to thereby change its volume. The volume of the propeller fairing is in this case in particular radially enlarged or widened.

If necessary, the volume of the propeller fairing can be expanded in a defined manner by means of a propeller fairing adjustment.

The change in the volume of the propeller fairing means in particular that the volume of the propeller fairing is intentionally adjusted or changed. The volume of the propeller fairing can be varied in particular on the system side. Whereby the change in volume of the propeller fairing can be variably controlled.

With the aero-drive device according to the invention, the disadvantages when the same propeller is used for vertical take-off or for hover flight "hover" (Hovern) and cruise flight can be minimized or suppressed.

In one embodiment, it is provided that the volume of the propeller fairing can be changed from the basic state to at least one expanded state by the propeller fairing adjustment device in such a way that the propeller front surface of the propeller is covered at least in regions by the volume-changed propeller fairing to a greater extent forward than in the basic state, in particular the propeller fairing covers the propeller front surface at least in regions by the side of the propeller fairing facing the propeller. The volume of the propeller fairing can be automatically changed from the basic state to at least one expanded state as a function of the adjustment quantity, for example by means of a propeller fairing adjustment device. For example, in at least one expanded state, the volume of the propeller fairing is widened or increased compared to the volume of the propeller fairing in the basic state. In the expanded state, the volume of the propeller fairing is particularly enlarged or widened compared to the volume of the propeller fairing in the basic state.

The volume of the propeller fairing can be varied, in particular, variably starting from a basic state. The volume in the expanded state can in particular be widened or enlarged or expanded stepwise.

In the basic state, the volume of the propeller fairing is not changed by the propeller fairing adjustment. In the basic state, the volume of the propeller fairing is not changed or influenced by the propeller fairing adjustment.

The expansion state, which is adapted to the respective situation or condition, can be set from a plurality of possible expansion states of the volume, for example, depending on the attitude of the aeronautical drive or the flight phase of the aircraft. In particular, for example, the formation of different expansion states can be adjusted. The volume of the propeller fairing can thus be converted, starting from the basic state, into an expanded state adapted to the respective situation.

In the expanded state, the front propeller surface of the propeller may be covered or isolated at least in regions, in particular locally, preferably completely, by means of the expanded propeller fairing. Since the volume of the propeller fairing expands or enlarges in at least one expanded state compared to the basic state, the propeller front surface of the propeller can be covered in a smaller or larger range compared to the basic state. This can be done dynamically by means of a propeller fairing adjustment.

In the expanded state, the inner propeller region (relative to the axis of rotation) of the propeller can be covered or isolated, for example, at least in regions, so that possible adverse properties for the flight operation of the aircraft in this region can be minimized. By isolating or covering the propeller front surface, in particular, at least one flow speed can be slowed down in such covered areas, so that no or only a small braking effect occurs. The efficiency or overall efficiency of the propeller can thereby be increased or increased during cruising flight of the aircraft.

The region or the side of the propeller that extends toward the propeller fairing can in particular be covered at least in regions by a changing volume. The side or region of the propeller fairing facing the propeller or pointing towards the propeller may here at least in regions cover the propeller front surface. The propeller front surface of the propeller may be, for example, a side of the propeller directed forward in the longitudinal direction of the aero drive. The side of the propeller fairing facing the propeller may in particular be a side which rests on the propeller and which extends in particular toward the center point of the propeller.

By at least locally covering the propeller front surface of the propeller, adverse flow in the region of the propeller near the hub during cruising flight of the aircraft can be prevented or reduced. It is thereby prevented that only small propulsive forces or thrusts are generated, but that disadvantageous resistances ("drag") are generated. In particular in many operating situations of an aircraft, the propulsion force may even be negative at high flight speeds, so that the inner part of the propeller may inhibit the air flow. This can likewise be minimized or reduced by the propeller front surface being at least regionally covered. Thus, a higher efficiency in cruising flight of the aircraft is produced, since the energy consumption can be reduced and the stroke length can be increased. Furthermore, less acoustic loads are generated both on the outside and on the inside of the aircraft during cruising flight.

In a further embodiment, it is provided that at least one partial surface of the front surface of the propeller, which is radially internal with respect to the rotational axis of the propeller and extends radially outward from the rotational axis, is covered by the propeller fairing in the radially expanded state of the propeller fairing, in particular over a larger extent in the radial direction than in the basic state. The inner propeller region of the propeller is thus covered in area at least in regions by the propeller fairing in the expanded state.

The radially inner partial surface of the front surface of the propeller corresponds, for example, to 20%, in particular 30%, in particular 40% of the total area of the front surface of the propeller.

The inner partial surface may, for example, correspond in particular to one third of the total area of the front surface of the propeller. The inner partial surface of the front surface of the propeller is arranged in particular in the region of the propeller hub or the rotor hub of the rotor.

In the expanded state, at least a partial region of the front surface of the propeller, which is located directly in the region of the axis of rotation, can be covered by the propeller fairing. In particular, the inner partial surface is a surface area of the front surface of the propeller extending away from the end of the distal end of the propeller. The covered portion of the inner partial surface can be varied in particular depending on the expansion state formed by the adjustment. In particular, the surface dimensions covered in the partial surface of the interior of the front surface of the propeller can be determined as a function of the expansion state selected by the propeller fairing adjustment.

In one embodiment, it is further provided that the rear end of the propeller fairing facing the propeller is radially expanded in the expanded state compared to the basic state. In particular, the region or the side of the propeller fairing that extends toward the propeller can thus be radially expanded. In this way, the front surface of the propeller, in particular the inner partial surface, can be covered or covered at least in regions in an efficient manner.

For example, the axis of rotation of the propeller fairing corresponds to the axis of rotation of the propeller.

In one embodiment, it is further provided that the propeller has at least two propeller blades, which are each connected to the drive shaft at a connection point of the propeller, wherein respective surface areas of the at least two propeller blades, which extend toward the connection point and away from respective radial end areas of the at least two propeller blades, are covered on the front side at least in regions by a propeller fairing, the volume of which is changed by a propeller fairing adjustment. The respective surface areas of the at least two propeller blades may in particular lie in a partial plane radially inward of the propeller front surface. In other words, the respective surface areas of the at least two propeller blades, which extend in a partial plane radially inward of the propeller front surface, can be covered or isolated at least in regions, in particular completely, by the propeller fairing, which changes in volume in the expanded state.

The propeller may in particular have at least two, in particular a plurality of propeller blades. The propeller blades may be referred to as blades or rotor blades, for example.

At least two propeller blades are each arranged at a connection point of the propeller and are thus connected to the drive shaft, so that the propeller blades are moved or rotated about the rotational axis by a rotational movement of the propeller at a predetermined rotational speed. The connection location of the propeller is in particular the center of the propeller. The rotation axis extends in particular through the connection location. The connection location may be referred to as a rotor hub or a propeller hub or a hub, for example. The connection position serves on the one hand to hold or fix the rotor blades of the rotor and to mechanically connect the rotor to the drive shaft, so that forces generated by the drive shaft can be transmitted to the rotor, in particular to the rotor blades. This is used in particular for driving an aircraft, in particular for advancing an aircraft.

The respective radial end region of the rotor blade may be the end of the distal end of the respective rotor blade. The corresponding radial end regions of the rotor blades are especially remote from the connection point.

In a further embodiment of the invention, it is provided that the respective surface area of the at least two propeller blades corresponds to at least 20%, in particular 30%, in particular 40% of the respective propeller front surfaces of the at least two propeller blades. In other words, the respective surface area is a radially inner partial surface of the propeller front surface of the propeller, which partial surface is covered in percentage form in accordance with the adjusted formed expanded state, corresponding to the adjusted formed expanded state of the propeller fairing. One third of the respective propeller front surfaces of the at least two propeller blades may be covered, for example, by means of an expanding propeller fairing. The inner propeller region extending in the region of the propeller hub is thus at least partially, in particular completely, covered into the expanded volume of the propeller fairing. The respective face area of the at least one propeller face may for example correspond to any value between 15% and 45% of the respective propeller front surfaces of the at least two propeller blades. The corresponding percentage value is adjusted according to the class or class of the state of expansion of the propeller fairing.

In one embodiment, it is provided that the propeller fairing is at least partially, in particular completely, composed of a material having anisotropic elasticity, the propeller fairing having at least one stiffening element on the outside in the circumferential direction. In particular, the material of the propeller fairing has anisotropic elastic properties at least in part, in particular completely. Anisotropic elastic properties are understood to mean direction-dependent properties, in particular material properties. The material forming part of the propeller fairing can thus have different elastic properties, for example, in the respective directions. The propeller fairing may thus have a high elasticity in the circumferential direction and a relatively low bending elasticity in the axial or radial direction, for example. Due to the high elasticity in the circumferential direction, the volume of the propeller fairing can be radially expanded. An increase in diameter can thus be achieved in the circumferential direction. The propeller fairing has a defined shape stability due to a low bending elasticity in the axial or radial direction. The shape stability is particularly important in cruising flight of an aircraft, since high, in particular extreme forces act on the propeller and in particular on the propeller fairing arranged in front of the propeller when the aircraft is in flight.

Additionally or alternatively, the propeller fairing may have at least one or more stiffening elements on the outside of the propeller fairing in the circumferential direction. In this case, an additional stiffening element is provided, so that the propeller fairing has a stable shape in terms of flight both in its basic state and in its expanded state, so that an efficient cruising flight of the aircraft can be carried out. The at least one reinforcing element may for example consist of a plurality of sub-elements. The at least one stiffening element is arranged, in particular as seen in the circumferential direction, on the outer side of the propeller fairing or on the outer shell. The material of the propeller fairing may be, for example, glass fibre reinforced polypropylene. The glass fiber reinforced polypropylene has in particular a different modulus of elasticity up to about a factor of 3 in both spatial directions.

Furthermore, the material of the propeller fairing may be polyurethane (TPU), for example. Polyurethane has high elasticity and can be reinforced, for example, by Carbon Fibers (CF).

The propeller fairing may, for example, have at least in regions a honeycomb structure which exhibits different elastic properties along different spatial directions. Such a structure can be realized, for example, by means of anisotropic TPU-CF materials.

In a further embodiment, it is provided that the housing of the propeller fairing is designed as a paraboloid, in particular that the housing of the propeller fairing can be radially expanded rotationally symmetrically about the axis of rotation. The shroud of the propeller fairing refers in particular to the outer shroud or outer shroud of the propeller fairing.

The paraboloid is the geometry of the second order surface. The shroud of the propeller fairing can in particular be designed as an elliptical paraboloid. The shell of the propeller fairing can be radially expanded in particular in order to be able to change or expand the volume of the propeller fairing. The housing is designed or arranged rotationally symmetrically about the axis of rotation and can be radially expanded or enlarged. The volume of the propeller fairing can thereby be varied or widened to cover at least a partial area of the front surface of the propeller.

The housing may in particular be a shell or a cover structure or a panel of a propeller fairing.

The propeller fairing can in particular be designed to be elastic.

In one embodiment, it is provided that the propeller fairing has a plurality of sheets (or lamellae) as an outer panel, which can be adjusted by a propeller fairing adjustment device, wherein the plurality of sheets are arranged in a basic state of the volume of the propeller fairing in a rotational direction around the rotational axis and are adjusted by the propeller fairing adjustment device in such a way that they have a predetermined distance from one another in order to change the volume of the propeller fairing.

In particular, the propeller fairing adjustment can be actuated automatically and thus the number of sheets can be changed or the number of sheets can be varied to change the volume. Thus, in one possible example, the propeller fairing may have a plurality of movable elements, for example a plurality of sheets as a shell or external panel (Verkleidung). The plurality of movable elements are positioned relative to each other in such a way that a change in the volume of the propeller fairing can be achieved.

In order to enlarge or increase the volume of the propeller fairing, the position or arrangement of the plurality of sheets is changed such that the sheets have a greater distance from each other. This is achieved in particular in the expanded state of the propeller fairing. In the basic or original state of the propeller fairing, a plurality of sheets are arranged overlapping each other. In order to change the volume of the propeller fairing to an expanded state, the sheets are changed from their overlapping arrangement to a spaced arrangement, so that in particular the volume of the propeller fairing is expanded. The arrangement of the sheets may vary depending on, inter alia, the type or state of the expanded state. This can be achieved in particular by a mechanical connection between the coupling of the sheet material and the propeller fairing adjustment. In particular, the adjustment of the sheet is effected automatically or automatically by means of a propeller fairing adjustment.

The sheets are arranged or positioned in the direction of rotation or circumferentially, in particular around the axis of rotation, as outer panels of the propeller fairing. In particular, the plurality of sheets are adjusted in the circumferential direction such that the sheets have a predetermined, in particular an increased, distance from one another when viewed in the circumferential direction. In the expanded state, the plurality of sheets may be arranged with respect to each other, for example, such that the plurality of sheets no longer overlap each other. In one possible expanded state, the plurality of sheets may be arranged at their outer edges at least regionally against each other.

In particular, a cup-shaped outer panel or shell of the propeller fairing can be formed by means of a plurality of sheets. In other words, the plurality of sheets may be fanned open for the expanded state of the propeller fairing.

The propeller fairing may in particular be composed of a plurality of sheets on the outside, the volume or size of which can be changed by a displacement of the sheets relative to one another.

In one embodiment, it is provided that the propeller fairing adjustment device is arranged in an interior region of the propeller fairing, wherein a movable adjustment element of the propeller fairing adjustment device is arranged in a front side of the propeller fairing facing away from the propeller, wherein the movable adjustment element is provided for movement by means of the propeller fairing adjustment device from the side facing away from the propeller toward the propeller in the interior region in order to change the volume of the propeller fairing. The volume of the propeller fairing can be varied here in particular by mechanical means.

The movable adjusting element may be, for example, an adjusting cone. The inner region of the propeller fairing is, for example, the hollow interior of the propeller fairing.

The movable adjusting element is arranged in particular in the inner region of the propeller fairing and can be controlled for movement by means of a propeller fairing adjustment. In the basic state of the propeller fairing, the movable adjusting element is located on the front side of the propeller fairing facing away from the propeller, i.e. in the region of the tip of the propeller fairing. In the expanded state of the propeller fairing, the movable adjusting element can be actuated and moved in such a way that it is moved, in particular pulled, from the front side of the propeller fairing facing away from the propeller toward the propeller, i.e. the side of the propeller fairing extending toward the propeller. By a movement of the adjusting element from the front side of the propeller fairing towards the rear side of the propeller fairing, a change in the volume of the propeller fairing can be produced. The volume of the propeller fairing can thereby be adjusted by means of a mechanical adjustment mechanism to cover at least one region of the front surface of the propeller.

In one embodiment, it is provided that the propeller fairing adjustment device has a pneumatic adjustment unit, wherein at least one inflatable element arranged in the interior region of the propeller fairing can be controlled by means of the pneumatic adjustment unit in order to change the volume of the propeller fairing. In this way, the volume of the propeller fairing can be adjusted in the simplest manner by inflating or re-deflating the inflatable element. In the basic state of the propeller fairing, the inflatable element is in particular in an uninflated or only partially inflated state.

In the expanded state of the propeller fairing, the inflatable element is in a partially, in particular fully inflated state. The inflatable element may be inflated variably depending on what expanded state is set and how much the front surface of the propeller is covered. This can be done by means of a propeller fairing adjustment. The at least one inflatable element or a plurality of inflatable elements may in particular be arranged in the interior space or in the interior region of the propeller fairing. The volume of the propeller fairing can thereby be varied by means of a pneumatic mechanism.

The propeller fairing can in this case be varied in its volume, in particular by pneumatic or hydraulic adjustment.

The inflatable element may be designed, for example, as an inflatable ring which is arranged in the circumferential direction in the inner region of the propeller fairing.

Another aspect of the invention relates to an aircraft having at least one aeronautical drive according to the preceding aspect or an advantageous development thereof. According to the invention, in hover flight of the aircraft, the axis of rotation of the propeller is oriented at a preset angle with respect to the longitudinal direction of the aircraft with respect to the vertical line, and in cruise flight of the aircraft, the axis of rotation of the propeller is oriented at a preset angle with respect to the longitudinal direction of the aircraft with respect to the horizontal line.

In hovering flight, the axis of rotation of the propeller may be arranged, for example, within a value interval of between ±10% with respect to the vertical line. The axis of rotation of the propeller may be arranged in a value interval of between + -10% with respect to the horizontal line when flying cruising.

In hover flight, the axis of rotation of the propeller may optionally be arranged perpendicular to the longitudinal direction of the aircraft. Furthermore, in cruising flight of the aircraft, the axis of rotation of the propeller may optionally be oriented parallel to the longitudinal direction of the aircraft.

The orientation of the axis of rotation of the propeller may vary, inter alia, depending on the flight phase or flight state of the aircraft.

The aircraft may be, for example, a vertical-takeoff and landing aircraft, which can take off vertically and land vertically. The aircraft may in particular change the flight mode or the flight state during the flight. The aircraft may be, for example, a helicopter. The aircraft may in particular be designed as an eVTOL ("vertical takeoff and landing aircraft"). An aircraft may be referred to as an air taxi, among other things.

The aircraft may be part of an aircraft fleet for providing efficient mobility solutions, for example.

The aircraft may have at least one aeronautical drive, in particular a plurality of aeronautical drives, in particular a propulsion device. For example, an aircraft may have an aeronautical drive according to the invention for each wing or wing. For example, two aeronautical drives according to the invention can likewise be provided for each wing.

The number of aeronautical drives may depend, for example, on the respective field of application of the aircraft.

In particular, the compromise, which describes the distinction between the operating state "hovering", i.e. no steering, and forward flight, i.e. having an incident flow, can be eliminated or minimized by means of the aircraft according to the invention and in particular by means of the aeronautical drive according to the invention. The propeller may for example generate usable lift in hover flight in the vicinity of the hub, i.e. in the vicinity of the propeller hub. In cruising flight, the propeller may produce at least a partially detrimental downward drive near the hub. This may also be the case in a variable pitch propeller. For example, in the case of a variable-pitch propeller, the entire propeller blade can be adjusted to a greater extent in response to a higher axial flow. The angle of attack can be varied here. This can be solved by the present invention, for example.

Another aspect of the invention relates to a method for operating an aeronautical drive of an aircraft, wherein a propeller of the aeronautical drive, which is arranged on a drive shaft of the aeronautical drive, is driven by the drive shaft about a rotational axis of the propeller. According to the invention, the volume of the propeller fairing arranged in a front region of the propeller, viewed in the direction of the axis of rotation of the aero drive, is changed in the radial direction relative to the axis of rotation by the propeller fairing adjustment device as a function of the attitude of the aero drive.

The method described so far can be carried out in particular by an aeronautical drive or an aircraft according to the preceding aspects or advantageous developments thereof. The aeronautical drive and/or the aircraft may have, in particular, means, in particular technical means, for carrying out or executing the method described immediately below.

The change in volume can be achieved automatically, in particular, as a function of the attitude of the aircraft or of the aeronautical drive.

The flight phase or flight mode or flight state of the aircraft can be characterized in particular by the attitude of the aeronautical drive. The aircraft can here perform, in particular, for example, a hover flight in helicopter mode. This occurs in particular in the takeoff phase and/or the climb phase of the aircraft. Hover flight also occurs when an aircraft descends and/or lands near or lands. Hover flight is understood to be a flight state in which the position and altitude of the flying device in the air are unchanged. Furthermore, cruise flight may be performed as a flight phase as the aircraft progresses or flies. For example, the phase of the air flight between climb and start of descent after reaching the planned cruising flight altitude may be referred to as cruising flight. If, for example, the flight level for performing cruising flight is reached, the aircraft and thus the aero drive are set in cruising flight mode in particular.

In one embodiment of the method described above, it is provided that the volume of the propeller fairing is changed from the basic state to at least one expanded state by the propeller fairing adjustment device in such a way that the propeller front surface of the propeller is covered at least in some areas by the volume-changed propeller fairing to a greater extent forward than in the basic state. At least one of the plurality of expanded states forming the propeller fairing can thereby be automatically adjusted, for example, as a function of the attitude of the aeronautical drive and/or the flight phase of the aircraft, so that in particular the volume of the propeller fairing can be expanded in order to cover at least one partial region of the front surface of the propeller.

In a further embodiment of the above method, it is provided that the volume of the propeller fairing is automatically changed when the aero-drive changes its attitude between a cruising flight attitude and a hovering flight attitude. Further, the volume of the propeller fairing may be set or changed or configured to an expanded state in the cruise flight attitude and may be set or changed or configured to a base state in the hover flight attitude. Depending on the attitude of the aeronautical drive and/or the operating state of the aircraft, the point in time and/or the duration for changing the volume of the propeller fairing and/or the volume size to which the volume of the propeller fairing is changed can be determined. This can be achieved, for example, by means of an electronic evaluation unit of the propeller fairing adjustment.

By means of an electronic evaluation unit, it is possible, for example, to determine or to ascertain at what point in time and for what duration the volume of the propeller fairing should be changed. This can be transmitted, for example, to a propeller fairing adjustment, in particular a control unit. Furthermore, it may be determined the volumetric size to which the volume of the propeller fairing will reach or change. Different information may be considered here. The operating state of the aircraft may be, for example, a flight phase. It is particularly important here whether the aircraft is in the takeoff phase or in the cruise flight phase.

Advantageous embodiments of one aspect may in particular be regarded as advantageous embodiments of another aspect and/or of all aspects. Advantageous embodiments of the aeronautical drive can be seen in particular as advantageous embodiments of the aircraft and the method. The advantageous embodiments of the method can likewise be regarded as advantageous embodiments of the aeronautical drive of the aircraft. This applies in the opposite way.

The invention also includes an extended design of the aircraft according to the invention and of the method according to the invention, which has the features already described in connection with the extended design of the aeronautical drive according to the invention. Accordingly, the corresponding developments of the aircraft according to the invention and of the method according to the invention are not described in detail here.

The invention also includes combinations of features of the described embodiments.

Drawings

Embodiments of the present invention are described below. In the drawings:

fig. 1 shows a schematic view of an aircraft with at least one aeronautical drive in cruising flight attitude;

FIG. 2 shows another schematic view of the aircraft of FIG. 1 in a hover flight attitude;

fig. 3 shows a schematic view of the aero-drive device of fig. 1, wherein the volume of the propeller fairing of the aero-drive device is in a basic state;

fig. 4 shows a further schematic view of the aero-drive device of fig. 1, wherein the volume of the propeller fairing of the aero-drive device is in an expanded state;

FIG. 5 illustrates in an exemplary side cross-sectional view of a propeller fairing a mechanism for changing the volume of the propeller fairing (shown here in a basic state);

FIG. 6 illustrates in another exemplary side cross-sectional view of a propeller fairing a mechanism for changing the volume of the propeller fairing (shown here in an expanded state);

fig. 7 shows a further schematic illustration of the aeronautical drive of fig. 1, wherein a special embodiment of a propeller fairing adjustment is shown here;

FIG. 8 illustrates in an exemplary side cross-sectional view of a propeller fairing a mechanism for changing the volume of the propeller fairing (shown here in a basic state);

FIG. 9 illustrates in another exemplary side cross-sectional view of a propeller fairing a mechanism for changing the volume of the propeller fairing (shown here in an expanded state);

FIG. 10 illustrates an exemplary front view of a propeller fairing having a plurality of adjustable sheets (shown here overlapping one another) as an exterior panel;

FIG. 11 illustrates an exemplary side view of the propeller fairing of FIG. 10;

FIG. 12 illustrates an exemplary front view of the propeller fairing of FIG. 10, wherein the sheets are here fanned open; and is also provided with

Fig. 13 shows an exemplary side view of the propeller fairing of fig. 12.

Detailed Description

The embodiments set forth below are the preferred embodiments of the present invention. In the embodiments, the described components represent individual features of the invention which can be considered independently of one another, which also each improve the invention independently of one another and are therefore also regarded as components of the invention, either individually or in combinations different from the combinations shown. Furthermore, the described embodiments can also be supplemented by other already described features of the invention.

In the drawings, elements having the same function are respectively provided with the same reference numerals.

Fig. 1 shows, for example, a schematic illustration of an aircraft 1. The aircraft 1 may be, for example, a vertical takeoff and landing aircraft or an eVTOL. The aircraft 1 is used in particular as a vehicle for urban air traffic. The aircraft 1 is in particular capable of taking off and landing vertically.

The aircraft 1 may have, for example, two wings 2 or wings. The aircraft 1 may have at least one aerodrive 3, so that the aircraft 1 can be operated and in particular advanced. The aeronautical drive 3 may be referred to, for example, as a propulsion unit or drive unit of the aircraft 1. In this embodiment, the aircraft 1 has one aeronautical drive 3 per wing 2.

The aero drive 3 may have a propeller 4. The propeller 4 may for example be referred to as an air propeller. The propeller 4 is arranged, for example, on a drive shaft 5 of the aero drive 3. The propeller 4 can be driven around the rotational axis 6 of the propeller 4 by means of this drive shaft, which may be referred to in particular as a mechanical drive. The rotation axis 6 refers to an axis about which the propeller 4 rotates. The rotation axis 6 may for example be oriented parallel to the drive shaft 5.

The aircraft 1 may in particular be in different flight phases. The flight phase may be, for example, a cruise flight or a cruise flight phase of the aircraft 1.

In particular, an aircraft 1 is shown in cruising flight in fig. 1. In cruising flight, the axis of rotation 6 of the propeller 4 is oriented at a preset angle to the horizontal with respect to the longitudinal 7 or longitudinal axis (corresponding to the x-axis) of the aircraft 1. For example, the rotation axis 6 and the longitudinal direction 7 may be referred to as being substantially parallel. The aero drive 3 can change its attitude for landing or take-off. For this purpose, mechanical adjusting means can be provided. This operation or state of the aircraft 1 is shown in fig. 2. Here a hover flight of the aircraft 1 is shown. The aircraft 1 can take off and land vertically (corresponding to the z-axis) by hovering flight. In particular in hovering flight of the aircraft 1, the rotation axis 6 of the propeller 4 is oriented at a preset angle to the vertical with respect to the longitudinal direction 7 of the aircraft 1. As shown in fig. 2, the rotation axis 6 may for example be considered substantially perpendicular to the longitudinal direction 7.

Returning again to fig. 1. Furthermore, the aerodrive 3 may have, in particular, a propeller fairing or fairing 8 as an aerodynamic protection. The propeller fairing 8 can be arranged in a front region 10 of the propeller 4, viewed in the direction 9 of the axis of rotation 6 of the aerodrive 3. In cruising flight of the aircraft 1, the direction 9 of the axis of rotation 6 may in particular be identical to the direction 11 of the longitudinal direction 7.

Thus, the propeller fairing 8 may be referred to as a front cover or tip of the propeller 4, for example. As shown in fig. 1, the propeller fairing 8 can be marked in particular in a position of the aerodrive 3 which is located at the forefront with respect to the direction 10.

In hover flight of the aircraft 1 (see fig. 2), the direction 9 of the rotation axis 6 may in turn be substantially perpendicular to the direction 11 of the longitudinal direction 7.

Fig. 3 shows a schematic view of the aero drive 3.

Due to the negative properties that may occur, for example, by the propeller 4, in particular in cruising flight of the aircraft 1, the aero drive 3 may have a propeller fairing adjustment 12. The propeller fairing adjustment is an automatic, electromechanical adjustment. In particular, an electromechanical system may be mentioned here. For example, each aerodrive 3 may be provided with its own propeller fairing adjustment 12. It is also conceivable to provide a central propeller fairing adjustment, by means of which all the aircraft drives 3 of the aircraft 1 can be controlled and/or regulated. The propeller fairing adjustment 12 can be referred to as a control unit, among other things.

In particular, the volume of the propeller fairing 8 can be varied in a defined manner in the radial direction 13 with respect to the axis of rotation 6 by means of the propeller fairing adjustment 12. Thus, the volume of the propeller fairing 8 can be reduced or increased, for example. In particular, an automatic radial expansion or radial expansion of the propeller fairing 8 can be performed by means of the propeller fairing adjustment device 12. The volume of the propeller fairing 8 can be varied or adapted or adjusted, for example, depending on the attitude of the aeronautical drive 3 and/or the flight phase of the aircraft 1.

The volume of the propeller fairing 8 can be changed from a basic state (which can be seen in fig. 3) to at least one expanded state (which can be seen in fig. 4), for example, by means of the propeller fairing adjustment 12. The volume in the expanded state (see fig. 4) is in particular expanded or increased compared to the basic state. As already mentioned, fig. 4 shows one possible expanded state of the different expanded states of the volume of the propeller fairing 8. The volume of the propeller fairing 8 can in particular be varied in such a way that the propeller front part of the propeller front surface 14 of the propeller 4 is covered at least in regions by the volume-varied propeller fairing 8. In this case, the propeller 8 is covered in particular (as seen in the direction 9 of the axis of rotation 6) in a forward direction. In other words, the front region 10 of the propeller 4 may be covered at least in regions. In particular, the area of the propeller 8 that generates negative thrust or is driven downwards that reduces efficiency can be covered by the volume 8 that changes in the expanded state. A more efficient cruising flight can thereby be achieved, so that in particular an increased stroke length of the aircraft 1 can be achieved.

Furthermore, the propeller front surface 14 may be the entire surface of the propeller 4 with reference to the front region 10 of the propeller 4.

The propeller fairing 8 can in the expanded state at least in some areas, in particular completely, cover or mask the propeller front surface 14 with the side 15 of the propeller fairing 8 facing the propeller 4. At least one partial surface 16 of the propeller front surface 14, which is located radially inward with respect to the axis of rotation 6 of the propeller 4 and extends radially outward from the axis of rotation 6, may in particular be covered by the propeller fairing 8 in its radially expanded state. The inner partial surface 16 extends in particular from the rotation axis 6 in the radial direction 13. In the expanded state, the inner partial surface 16 is covered, in particular over a radially greater extent, than in the basic state (see fig. 3). As can also be seen from fig. 4, the rear end 17 of the propeller fairing 8 facing the propeller 4 is radially expanded in the expanded state compared to the basic state. The propeller fairing expands or enlarges further, in particular with reference to the radial direction 13. The rear end 17 is located, in particular with reference to the direction 9, on the opposite end of the propeller fairing 8.

The propeller 4 has, for example, at least two propeller blades 19, 18. Alternatively, the propeller 4 may have a plurality of propeller blades 18, 19. The propeller blades 18, 19 are connected or mechanically coupled to the drive shaft 5 at a connection location 20 of the propeller 4. The connection location 20 may in particular be the center of the propeller 4. The connection location 20 is in particular a propeller hub or a rotor hub. The rotation axis 6 can extend centrally through the connection point 20, for example, so that the connection point 20 can likewise be rotated symmetrically about the rotation axis 6. The connection point 20 can be connected, for example, to the drive shaft 5 along the rotation axis 6 in order to rotate the propeller 4, in particular the propeller blades 18, 19, as a function of the rotational speed.

The respective surface areas 21, 22 of the at least two propeller blades 18, 19 can be covered, for example, on the front side with respect to the front area 10, at least in regions by the propeller fairing 8, the volume of which is changed by the propeller fairing adjustment 12. The two surface areas 21, 22 form, for example, the inner partial surface 16.

The respective surface regions 21, 22 extend in particular toward the connection point 20 and away from the respective radial end regions 23, 24 of the at least two propeller blades 18, 19. The respective surface areas 21, 22 can thus be located near the center of the connection point 20 and in particular near the center of the propeller 4.

The respective surface area 21, 22 may in particular correspond to at least 20%, in particular 30%, in particular 40% of the respective propeller front surface 14 of the at least three propeller blades 18, 19. Thereby, for example, the inner propeller region of the propeller 4 can be covered. The respective surface area 21, 22 may for example correspond to one third, in particular one quarter, of the front surface of the respective propeller blade 18, 19.

In particular one third, in particular one quarter, of the propeller front surface 14 can be covered by the propeller fairing 8, the volume of which changes in the expanded state.

The propeller fairing 8 can be made at least partially, in particular completely, of a material having anisotropic elasticity, for example. The propeller fairing 8 may have at least one stiffening element 26 (see fig. 8) on the outside 27, for example along the circumferential direction 25. At least one stiffening element 26 is in particular a stabilizing element to improve the stability of the propeller fairing 8, in particular during cruising flight. The propeller fairing 8 may in particular have a plurality of stiffening elements 26.

The propeller fairing 8 may, for example, have a shell 28 (see fig. 1). The housing 28 may be referred to as an outer housing or an outer housing, for example. The housing 28 can in particular be of parabolic design. The shroud 28 and in particular the propeller fairing 8 therefore has a parabolic-like shape. The housing 28 can in particular be radially expanded rotationally symmetrically about the axis of rotation 6, so that the volume of the propeller fairing 8 can be varied.

Fig. 5 shows in particular a possible embodiment or mechanism for changing the volume of the propeller fairing 8. The propeller fairing adjustment device 12 can be arranged for this purpose, for example, in an interior region 29 or in a cavity of the propeller fairing 8. The movable adjusting element 30 of the propeller fairing adjusting device can be arranged here (with reference to the direction 9 of the axis of rotation 6) in a front side 31 facing away from the propeller 4. Fig. 5 shows in particular again the basic state of the propeller fairing 8 and in particular of the movable adjusting element 30. Fig. 6 shows at least one expanded state of the propeller fairing 8. The basic state is again shown here visually by the dashed line 32. The movable adjusting element 30 is moved by the propeller fairing adjustment 12 from the front side 31 toward the propeller 4 in order to change the volume in the interior 29. The movable adjusting element 30 can be moved for this purpose, for example, by means of the spindle 33 in the direction of the propeller 4 (opposite to the direction 9). The adjusting element 30 is moved here in particular toward the counter element 34. Expansion or change of volume can be produced by such movement within the propeller fairing 8.

Another possibility for changing the volume is shown in fig. 7. The propeller fairing adjustment device 12 can be arranged outside the propeller fairing 8. This can be achieved, for example, in the region of the propeller 4 which is remote opposite to the direction 9. However, in this case, in contrast to the embodiment in fig. 6, the spindle 33 or the threaded spindle is arranged outside the propeller fairing 8, in particular completely outside the propeller fairing 8. The propeller fairing adjustment device 12 can have an electric motor 35 for this purpose, for example. The motor 35 may have, for example, a housing 36, a stator 37, a rotor 38, and a hollow shaft 39. Furthermore, bearings 40 may be provided. In order to adjust the movable adjusting element 30, an adjusting actuator 41 can be provided. The adjustment actuator can be operated by means of an electric motor 35. The adjustment actuator 41 may in particular be arranged within the propeller fairing 8. For this purpose, for example, a cable guide can be provided. The electric motor 35 has, in particular, a cooling air guide 42.

The propeller fairing 8 shown in fig. 7 may in particular be a torsion-resistant fairing.

Another possibility for changing the volume is shown in fig. 8. The propeller fairing adjustment device 12 can have a pneumatic or hydraulic adjustment unit 43. The adjusting unit 43 may in particular be arranged in the inner region 29 of the propeller fairing 8. At least one inflatable element 44 arranged in the interior region 29 can be controlled by means of a pneumatic control unit 43, which can be controlled and/or regulated by the propeller fairing adjustment 12. The inflatable element can be inflated in this case to change the volume, in particular to expand the volume. Fig. 8 shows in particular the basic state of the propeller fairing 8.

Fig. 9 again shows the expanded state. In fig. 9, at least one inflatable element 44, for example an inflatable ring, is inflated, in particular filled with air or gas, so that the volume of the propeller fairing 8 expands. The inflatable element 44 can be controlled in particular by means of a pneumatic control unit 43. The inflatable element can be inflated or deflated again, depending on the volume requirements of the propeller fairing 8.

Another possibility for changing the volume of the propeller fairing 8 is shown in the following fig. 10 to 13.

Fig. 10 shows a front view of the propeller fairing 8, for example, from the front region 10.

The propeller fairing 8 can have, for example, a plurality of sheets 46 as the outer panel 45, which can be adjusted by the propeller fairing adjustment 12. Fig. 10 again shows the original state 32 of the propeller fairing 8. In the basic or original state 32, the sheets 46 are arranged overlapping each other about the rotation axis 6 in the circumferential direction 25 or the rotation direction. For this purpose, a side view is shown, for example, in fig. 11.

To change the volume 8, the sheet 46 can be adjusted or changed such that the sheet 46 opens, in particular in a fan shape. This is shown in fig. 12. The sheet 46 is actuated in this case, in particular by means of the propeller fairing adjustment 12, in such a way that it opens in a fan-shaped manner. Thereby radially expanding the volume. This can be seen in fig. 12 between a comparison with the basic state 32. The plurality of sheets 46 are controlled or adjusted in such a way that the plurality of sheets 46 have a predetermined distance 47 from one another. This can be seen for example from fig. 13. The volume of the propeller fairing 8, in particular of the elastic propeller fairing 8, can thus be expanded or increased by the spaced-apart sheets 46.

In one embodiment of the invention, the volume of the propeller fairing 8 can be varied in the radial direction 13 with respect to the axis of rotation 6 automatically by means of the propeller fairing adjustment 12, in particular as a function of the attitude of the aeronautical drive 3 and/or the flight phase of the aircraft 1. The volume of the propeller can thus be adjusted on the system side by means of an electromechanical system.

Furthermore, the volume of the propeller fairing 8 can be changed from the basic state 32 to at least one expanded state, for example, by means of the propeller fairing adjustment device 12, in such a way that the propeller front surface 14 of the propeller 4 is covered at least in some areas by the volume-changed propeller fairing 8 to a greater extent forward than in the basic state 32. This can likewise be accomplished by an automated system, in particular a control and/or regulating device.

Furthermore, the volume of the propeller fairing 8 may for example be automatically changed when the attitude of the aero-drive 3 is changed between a cruising flight attitude (see fig. 1) and a hovering flight attitude (see fig. 2). The propeller fairing adjustment device 12 can have an electronic evaluation unit (see fig. 3) for this purpose, for example. The volume of the propeller fairing 8 may in particular be set to an expanded state in the cruising flight attitude and to a basic state in the hovering flight attitude. Depending on the respective attitude of the aeronautical drive and/or the operating state of the aircraft 1, the point in time and/or the duration for changing the volume of the propeller fairing 8 and/or the volume size to which the volume of the propeller fairing 8 is changed can be determined. This can be determined by means of an electronic evaluation unit or a calculation unit 48 and transmitted to the respective unit.

The propeller fairing 8 may, for example, have a shape memory alloy, by means of which the shape of the propeller fairing 8 can be changed. The actuation or the plurality of actuations for changing the volume of the propeller fairing 8 can be effected, for example, by means of piezo actuation or actuation by centrifugal force.

List of reference numerals

1. Aircraft with a plurality of aircraft body

2. Wing

3. Aviation driving device

4. Propeller propeller

5. Driving shaft

6. Axis of rotation

7. Longitudinal direction

8. Propeller fairing

9. Direction of rotation axis

10. Front region of propeller

11. Longitudinal direction of an aircraft

12. Propeller fairing adjusting device

13. Radial direction

14. Front surface of propeller

15. One side of the propeller fairing facing the propeller

16. Internal partial surface of the front surface of the propeller

17. Rear end of propeller fairing

18. 19 propeller blade

20. Connection location

21. 22 area of surface

23. 24 radial end regions

25. Circumferential direction

26. Reinforcing element

27. Outside is provided with

28. Shell cover

29. Interior region

30. Adjusting element

31. Front side of propeller fairing

32. Basic state

33. Main shaft

34. Mating element

35. Motor with a motor housing having a motor housing with a motor housing

36. Motor casing

37. Stator of motor

38. Rotor of motor

39. Hollow shaft

40. Bearing

41. Adjusting actuator

42. Cooling air guide device

43. Pneumatic adjusting unit

44. Inflatable element

45. Exterior panel

46. Multiple sheets

47. Distance between sheets

48. Electronic analysis unit

Claims (15)

1. An aeronautical drive (3) for an aircraft (1), the aeronautical drive having:

a propeller (4) which is arranged on a drive shaft (5) of the aeronautical drive (3) and which can be driven about a rotation axis (6) of the propeller (4) by means of the drive shaft (5),

a propeller fairing (8) arranged in a front region (10) of the propeller (4) viewed in the direction (9) of the axis of rotation (6) of the aerodrive (3),

it is characterized in that

-a propeller fairing adjustment device (12) for changing the volume of the propeller fairing (8) in a defined manner along a radial direction (13) relative to the axis of rotation (6).

2. Aviation drive (3) according to claim 1,

It is characterized in that the method comprises the steps of,

the volume of the propeller fairing (8) can be changed from a basic state to at least one expanded state by means of the propeller fairing adjustment device (12) in such a way that the propeller front surface (14) of the propeller (4) is covered at least in regions by the volume-changed propeller fairing (8) to a greater extent forward than in the basic state, in particular the propeller fairing (8) covers the propeller front surface (14) at least in regions with the side (15) of the propeller fairing (8) facing the propeller (4).

3. Aviation drive (3) according to claim 2,

it is characterized in that the method comprises the steps of,

at least one partial surface (16) of the propeller front surface (14) which is radially internal with respect to the axis of rotation (6) of the propeller (4) and which extends radially outwards from the axis of rotation (6) is covered by the propeller fairing (8) in its radially expanded state, in particular in a radially larger extent than in the basic state.

4. An aeronautical drive device (3) according to claim 2 or 3,

it is characterized in that the method comprises the steps of,

the rear end (17) of the propeller fairing (8) facing the propeller (4) expands radially in an expanded state compared to a basic state.

5. Aviation drive (3) according to one of the preceding claims,

it is characterized in that the method comprises the steps of,

the propeller (4) has at least two propeller blades (18, 19) which are each connected to the drive shaft (5) at a connection point (20) of the propeller (4), wherein respective surface areas (21, 22) of the at least two propeller blades (18, 19) which extend toward the connection point (20) and away from respective radial end areas (23, 24) of the at least two propeller blades (18, 19) are covered on the front side at least in regions by a propeller fairing (8) whose volume is changed by the propeller fairing adjustment device (12).

6. Aviation driving device (3) according to claim 5,

it is characterized in that the method comprises the steps of,

the respective face areas (21, 22) of the at least two propeller blades (18, 19) correspond to at least 20%, in particular 30%, in particular 40% of the respective propeller front surfaces (14) of the at least two propeller blades (18, 19).

7. Aviation drive (3) according to one of the preceding claims,

it is characterized in that the method comprises the steps of,

the propeller fairing (8) is at least partially, in particular completely, made of a material having anisotropic elasticity, in particular the propeller fairing (8) having at least one reinforcing element (26) on the outside (27) in the circumferential direction (25).

8. Aviation drive (3) according to one of the preceding claims,

it is characterized in that the method comprises the steps of,

the shroud (28) of the propeller fairing (8) is designed as a parabolic surface, in particular the shroud (28) of the propeller fairing (8) can be expanded radially rotationally symmetrically about the axis of rotation (6).

9. Aviation drive (3) according to one of the preceding claims,

it is characterized in that the method comprises the steps of,

the propeller fairing (8) has a plurality of sheets (46) which can be adjusted by the propeller fairing adjustment device (12) as an outer panel (45), wherein the plurality of sheets (46) are arranged overlapping each other along a circumferential direction (25) around the rotational axis (6) in a basic state of the volume of the propeller fairing (8) and for changing the volume of the propeller fairing (8) the plurality of sheets (46) are adjusted by the propeller fairing adjustment device (12) such that the plurality of sheets (46) have a predetermined distance (47) from each other.

10. Aviation drive (3) according to one of the preceding claims,

it is characterized in that the method comprises the steps of,

the propeller fairing adjustment device (12) is arranged in an interior region (29) of the propeller fairing (8), wherein a movable adjustment element (30) of the propeller fairing adjustment device (12) is arranged on a front side (31) of the propeller fairing (8) facing away from the propeller (4), wherein the movable adjustment element (30) is provided for movement within the interior region (29) by means of the propeller fairing adjustment device (12) from the side (31) facing away from the propeller (4) toward the propeller (4) in order to change the volume of the propeller fairing (8).

11. Aviation drive (3) according to one of the preceding claims 1 to 9,

it is characterized in that the method comprises the steps of,

the propeller fairing adjustment device (12) has a pneumatic adjustment unit (43), wherein at least one inflatable element (44) arranged in the interior region (29) of the propeller fairing (8) can be controlled by means of the pneumatic adjustment unit (43) to change the volume of the propeller fairing (8).

12. An aircraft (1) having at least one aeronautical drive (3) according to one of the preceding claims 1 to 11,

it is characterized in that the method comprises the steps of,

in hover flight of the aircraft (1), the axis of rotation (6) of the propeller (4) is oriented at a preset angle to a vertical line with respect to the longitudinal direction (7) of the aircraft (1), and in cruise flight of the aircraft (1), the axis of rotation (6) of the propeller (4) is oriented at a preset angle to a horizontal line with respect to the longitudinal direction (7) of the aircraft (1).

13. A method for operating an aeronautical drive (3) of an aircraft (1), wherein a propeller (4) of the aeronautical drive (3) arranged on a drive shaft (5) of the aeronautical drive (3) is driven by the drive shaft (5) around a rotational axis (6) of the propeller (4),

It is characterized in that the method comprises the steps of,

the volume of the propeller fairing (8) arranged in a front region (10) of the propeller (4) viewed in the direction (9) of the axis of rotation (6) of the aerodrive (3) is varied by the propeller fairing adjustment (12) in the radial direction (13) relative to the axis of rotation (6) as a function of the attitude of the aerodrive (3).

14. The method according to claim 13,

it is characterized in that the method comprises the steps of,

the volume of the propeller fairing (8) is changed from a basic state to at least one expanded state by the propeller fairing adjustment device (12) such that the propeller front surface (14) of the propeller (4) is covered at least in regions by the volume-changed propeller fairing (8) to a greater extent forward than in the basic state.

15. The method according to claim 14,

it is characterized in that the method comprises the steps of,

when the aero-drive device (3) changes its attitude between a cruising flight attitude and a hovering flight attitude, the volume of the propeller fairing (8) is automatically changed, in particular the volume of the propeller fairing (8) is set to an expanded state in the cruising flight attitude and to a basic state in the hovering flight attitude, in particular the point in time and/or the duration for changing the volume of the propeller fairing (8) and/or the volume size to which the volume of the propeller fairing (8) is changed are determined as a function of the attitude of the aero-drive device (3) and/or the operating state of the aircraft (1).

Images