DE102022200010B4 - Aviation propulsion system for an aircraft, as well as aircraft with a corresponding aviation propulsion system and method for operating an aviation propulsion system - Google Patents

Abstract

Aviation drive (3) for an aircraft (1), comprising:- a propeller (4) which is arranged on a drive shaft (5) of the aviation drive (3) and can be driven by means of the drive shaft (5) about a rotation axis (6) of the propeller (4),- a propeller spinner (8) which is arranged in the direction (9) of the rotation axis (6) of the aviation drive (3) viewed front region (10) of the propeller (4), characterized by- a propeller spinner adjustment device (12) for definedly changing the volume of the propeller spinner (8) in the radial direction (13) to the rotation axis (6), wherein the volume of the propeller spinner (8) can be changed in the radial direction (13) from a basic state to at least one expansion state with the propeller spinner adjustment device (12) such that a propeller front surface (14) of the propeller (4) can be changed at least in regions by the volume-changed Propeller spinner (8) is covered towards the front more than in the basic state.

Description

The invention relates to an aviation drive for an aircraft, which has a propeller which is arranged on a drive shaft of the aviation drive and can be driven by means of the drive shaft about a rotation axis of the propeller. Furthermore, the aviation drive has a propeller spinner which is arranged in the front region of the propeller as viewed in the direction of the rotation axis of the aviation drive.

Furthermore, the invention relates to an aircraft with at least one aviation drive. The invention also relates to a method for operating an aviation drive of an aircraft, wherein a propeller of the aviation drive, which is arranged on a drive shaft of the aircraft, is driven by the drive shaft about a rotation axis of the propeller.

For example, "Personal Air Vehicles" (PAV) or aircraft that can take off and land vertically (eVTOL "electric Vertical Take-Off and Landing aircraft") are being developed for future mobility solutions. Such aircraft concepts can use a common propeller for the vertical take-off process as well as for cruising. For example, the "tilt-wing concept" or "tilt-rotor concept" can be applied here. In these concepts, in contrast to "lift-and-cruise concepts", separate motor-propeller units can be used for both take-off and cruising, so that the mass of the aircraft can be minimized.

The efficiency of the propeller has a significant influence on the range of such aircraft, particularly the electric range. However, the propeller design in these concepts often represents a compromise, as it must be tailored to both hovering (or take-off) and cruising flight. For example, variable-pitch propellers are used as standard in classic aircraft. The individual propeller blades of the propeller rotate synchronously around their longitudinal axis and are thus adapted to the respective flight situation. This means that good efficiency can be achieved both during take-off (no airflow speed due to the aircraft movement) and during cruising flight (airflow speed due to airspeed).

The state of the art, for example, discloses variable propeller spinners for the targeted influencing of the cooling air flow for combustion engines arranged behind them as well as propeller spinners optimized for aircraft with a “tilt rotor concept”.

For example, the US 2020/0223 552 A1 a rotor assembly for use in an aircraft, comprising a rotor hub, a spindle structure including a spinner opening, and a rotor blade. The rotor blade has a rotor root located near the rotor hub. The rotor assembly also includes a movable fairing surface resting at least partially along the rotor hub.

Furthermore, the US 2018 / 0 334 240 A1 as a spinner fairing, a base configured to be fixed relative to a hub system; a movable spinner assembly movable relative to the base; wherein the movable spinner assembly comprises a first movable member and a second movable member. Each first and second movable member is selectively configurable between a closed position and a contracted position in which the movable spinner assembly has a reduced shape and/or volume.

One disadvantage is that the rotor blade is rotated as a whole, but the flow situation near the hub (small radius) and near the blade tip (large radius) is different. This represents a compromise that does not exploit the full efficiency of a propeller. Likewise, the variation of engine speed and angle of attack only provides a limited opportunity (degrees of freedom) to increase efficiency.

An object of the present invention is therefore to improve the efficiency of an aircraft propulsion system, in particular a propeller.

This object is achieved by an aviation engine, an aircraft and a method according to the independent patent claims. Useful further developments arise from the dependent patent claims.

• - einen Propeller, welcher an einer Antriebswelle des Luftfahrtantriebs angeordnet ist und mittels der Antriebswelle um eine Rotationsachse des Propellers antreibbar ist,
• - einen Propellerspinner, welcher in Richtung der Rotationsachse des Luftfahrtantriebs betrachteten vorderen Bereich des Propellers angeordnet ist,
• - eine Propellerspinner-Verstelleinrichtung zum definierten Verändern des Volumens des Propellerspinners in radialer Richtung zur Rotationsachse.

One aspect of the invention relates to an aviation drive for an aircraft, comprising:

• - a propeller which is arranged on a drive shaft of the aircraft engine and can be driven by the drive shaft about a rotation axis of the propeller,
• - a propeller spinner, which is arranged in the front area of the propeller viewed in the direction of the axis of rotation of the aircraft engine,
• - a propeller spinner adjustment device for the defined change of the volume of the propeller spinner in the radial direction to the axis of rotation.

With the aviation drive according to the invention, an aircraft or a flying device can be operated more efficiently. The efficiency of the propeller can be increased by the defined change in the volume of the propeller spinner with the help of the propeller spinner adjustment device. For example, an increase in efficiency of 10%, in particular 20%, especially 25% can be achieved compared to the prior art propeller.

The aviation drive according to the invention can increase the range of the aircraft when carrying out a cruise flight. This is achieved through the improved efficiency of the aviation drive. The more efficient aviation drive means that the aircraft can, for example, carry more payload. In particular, the aircraft's payload can be increased with the help of the aviation drive according to the invention while maintaining the same range.

In particular, the propeller spinner adjustment device can be used to provide a variable propeller spinner for aircraft. For example, with the propellers in the prior art, it can happen that when the aircraft is cruising, a local downforce occurs near the hub of the propeller instead of lift (propeller thrust). For example, near the hub, propeller blades tend to brake the aircraft instead of driving it. For example, averaged over a propeller radius, a positive propeller thrust still results as lift, but with a loss in efficiency. These disadvantages can be caused, for example, by the defined change in the volume of the propeller spinner according to the invention, so that, for example, such negative areas near the hub can be sealed off or covered. This can increase the efficiency of the propeller and in particular of the aircraft drive. In particular, the propeller spinner can be a propeller spinner that is dynamically adjustable in size or volume, which can be changed or varied using the propeller spinner adjustment device in such a way that, for example, areas of the propeller that are detrimental to efficiency can be covered or sealed off. This can increase the overall efficiency of a cruise flight of the aircraft.

In particular, the propeller spinner adjustment device can be used to carry out a defined change or adjustment of the volume or diameter of the propeller spinner, thereby increasing the efficiency of the aircraft propulsion system and the aircraft during cruise flight.

For example, the aircraft can be a convertible aircraft, which can be described as a vertical take-off and vertical landing aircraft. In particular, convertible aircraft are able to change flight modes (flight conditions) during flight. Flight conditions relevant for a convertible aircraft include, for example, hovering in helicopter mode, the subsequent transition from vertical to horizontal flight and horizontal flight as a fixed-wing aircraft.

For example, the aircraft engine may be a tilt rotor. For example, the aircraft may be designed as a tilt-wing aircraft.

In particular, the aircraft is a "vertical take-off and landing aircraft" (eVTOL). The aviation propulsion system can therefore be used for an aircraft designed in this way. For example, the aircraft can be part of urban air mobility, such as air taxis.

In particular, the aircraft is capable of performing a vertical take-off and a vertical landing.

The propeller can be, in particular, an aircraft propeller. The propeller can be used to generate shaft power from an aircraft engine or shaft turbine propulsion or thrust, for example.

In particular, the propeller can be designed as a variable-pitch propeller, whereby the angle of attack of the propeller blades can be made variable in a variable-pitch propeller, whereby the angle of attack of the propeller blades can be adapted to different operating situations of the aircraft. The propeller and the axis of rotation can be driven with the help of the drive shaft, so that the propeller can be brought to a predetermined speed. For example, the drive shaft can be designed parallel to the axis of rotation.

The propeller spinner can be a spinner from aviation, which can be a streamlined fairing of an aircraft in front of the propeller in the middle of the engine or in turbofan engines. The propeller spinner serves, for example, to reduce air resistance and thus ensure an improved airflow to the aircraft's engine.

For example, the aviation engine can be referred to as the engine or engine unit of the aircraft.

For example, the propeller spinner can be used to cover at least part of a propeller head, in particular completely. For example, the propeller spinner can reach up to the cowling of an aircraft engine or propulsion unit. Such a cowling of the aircraft engine can be referred to as a hood or engine nacelle, for example.

Specifically, the propeller spinner adjustment device can be an electromechanical or mechanical device. For example, the propeller spinner adjustment device can be controlled and/or regulated with the aid of a control and/or regulating device in order to change the volume of the propeller spinner. In particular, the change or adjustment or setting of the volume of the propeller spinner takes place automatically.

In particular, the volume changes depending on the flight position of the aircraft operation or the aircraft.

Optionally, the propeller spinner can be expanded radially using the propeller spinner adjustment device in order to change its volume. In particular, this results in a radial expansion or radial widening of the volume of the propeller spinner.

If necessary, the volume of the propeller spinner can be expanded in a defined manner using the propeller spinner adjustment device.

In particular, changing the volume of the propeller spinner involves intentionally adjusting or changing the volume of the propeller spinner. The volume of the propeller spinner can be changed in particular on the system side. This means that changing the volume of the propeller spinner can be controlled variably.

By means of the aviation propulsion system according to the invention, disadvantages when using one and the same propeller for vertical take-off or for hovering and cruising flight can be minimized or counteracted.

It is provided that with the propeller spinner adjustment device the volume of the propeller spinner can be changed from a basic state to at least one expanded state in such a way that a propeller front surface of the propeller is at least partially covered by the propeller spinner with its volume changed more towards the front than in the basic state, in particular the propeller spinner covers the propeller front surface at least partially with a side of the propeller spinner facing the propeller. For example, with the help of the propeller spinner adjustment device the volume of the propeller spinner can be changed automatically from a basic state to at least one expanded state depending on a control variable. For example, in the at least one expanded state the volume of the propeller spinner is expanded or enlarged compared to the volume of the propeller spinner in the basic state. In particular, in the expanded state the volume of the propeller spinner is expanded or enlarged compared to the volume of the propeller spinner in the basic state.

In particular, the volume of the propeller spinner can be variably changed starting from the basic state. In particular, the volume in the expansion state can be gradually expanded or extended or widened.

In the basic state, the volume of the propeller spinner has not been changed by the propeller spinner adjustment device. In the basic state, the volume of the propeller spinner is not changed or influenced by the propeller spinner adjustment device.

For example, depending on the position of the aircraft engine or the flight phase of the aircraft, an expansion state adapted to the respective situation or circumstances can be set from a large number of possible expansion states of the volume. In particular, a wide variety of expansion states can be set. The volume of the propeller spinner can thus be converted from the basic state into an expansion state adapted to the respective situation.

In the expanded state, the propeller front surface of the propeller can be covered or concealed or sealed off at least in some areas, in particular partially, preferably completely, by means of the expanded propeller spinner. Due to the expanded or extended volume of the propeller spinner in the at least one expanded state compared to the basic state, the The front surface of the propeller can be covered more or more than in the basic state. This can be done dynamically using the propeller spinner adjustment device.

For example, in the expanded state, an inner propeller area of the propeller (with respect to the axis of rotation) can be covered or sealed off at least in some areas, so that any negative properties in this area on the flight operation of the aircraft can be minimized. In particular, by sealing off or covering the propeller front surface, at least one flow speed in such a covered area can be slowed down, so that no or only a slight braking effect occurs. This can increase or boost the efficiency or overall efficiency of the propeller during cruise flight of the aircraft.

In particular, the area or the side of the propeller that extends towards the propeller spinner can be covered at least in part by the changed volume. The side or the area of the propeller spinner that faces the propeller or is directed towards the propeller can cover the propeller front surface at least in part. For example, the front propeller surface of the propeller can be the side of the propeller that is directed forward in the longitudinal direction of the aircraft drive. In particular, the side of the propeller spinner that faces the propeller can be the side that rests against the propeller and in particular extends towards a center point of the propeller.

By covering at least part of the propeller front surface, unfavorable airflows in the propeller area near the hub during cruise flight of the aircraft can be prevented or reduced. This can prevent only a small amount of propulsion or thrust but a negative resistance (“drag”) from being generated. In particular, in many operating situations of the aircraft, propulsion at high flight speeds can even be negative, so that the inner part of the propeller can slow down the air flow. This can also be minimized or reduced by covering at least part of the propeller front surface. This results in greater efficiency during cruise flight of the aircraft, as energy consumption can be reduced and the range can be increased. Furthermore, there is less acoustic pollution during cruise flight, both outside and inside the aircraft.

In a further embodiment, it is provided that at least one partial surface of the propeller front surface which is radially inner with respect to the axis of rotation of the propeller and which extends radially outward from the axis of rotation is covered by the propeller spinner in its radially expanded state, in particular is covered radially more than in the basic state. Thus, an inner propeller region of the propeller is covered in terms of area at least in part in the expanded state by the propeller spinner.

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

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

With the help of the propeller spinner, in the expanded expansion state, at least the partial area of the propeller front surface that is located directly in the area of the axis of rotation can be covered. Specifically, the inner partial area is the area of the propeller front surface that extends away from a distal end of the propeller. In particular, the proportion of the inner partial area that is covered can vary depending on a set expansion state. In particular, depending on an expansion state selected by the propeller spinner adjustment device, an area size can be determined that is covered within the inner partial area of the propeller front surface.

In one embodiment, it is further provided that a rear end of the propeller spinner facing the propeller is radially expanded in the expanded state compared to the basic state. Consequently, in particular the area or side of the propeller spinner which extends towards the propeller can be radially expanded. As a result, the propeller front surface, in particular the inner partial surface, can be covered or concealed at least in areas in an efficient manner.

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

In one embodiment, it is further provided that the propeller has at least two propeller blades, each of which is connected to the drive shaft at a connection point of the propeller, wherein a respective surface area of the at least two propeller blades, which extends towards the connection point and away from a respective radial end area of the at least two propeller blades, is at least partially covered at the front by the propeller spinner whose volume is changed by the propeller spinner adjustment device. In particular, the respective surface area of the at least two propeller blades can be located within the radially inner partial area of the propeller front surface. In other words, the respective surface area of the at least two propeller blades, which extends within the radially inner partial area of the propeller front surface, can be at least partially, in particular completely, covered or sealed off by means of its propeller spinner whose volume is changed in the expanded state.

In particular, the propeller can have at least two propeller blades, in particular several propeller blades. For example, the propeller blades can be referred to as blades or rotor blades.

The at least two propeller blades are each arranged at the connection point of the propeller and thus connected to the drive shaft, so that a rotational movement of the propeller moves or rotates the propeller blades around the axis of rotation at a predetermined speed. The connection point of the propeller is in particular the center of the propeller. In particular, the axis of rotation runs through the connection point. For example, the connection point can be referred to as a rotor hub or propeller hub or hub. The connection point serves to hold or fix the rotor blades of the rotor and to mechanically connect the rotor to the drive shaft so that a force generated by the drive shaft can be transmitted to the rotor, in particular to the rotor blades. This serves in particular to drive the aircraft, in particular to move it forward.

The respective radial end region of the rotor blades can be a distal end of a respective rotor blade. In particular, the respective radial end region of the rotor blades is removed 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 a respective propeller front surface of the at least two propeller blades. In other words, the respective surface area is the radially inner partial surface of the propeller front surface of the propeller, which is covered in percentage terms depending on the set expansion state of the propeller spinner. For example, a third of the respective propeller front surface of the at least two propeller blades can be covered with the aid of the expanded propeller spinner. Thus, an inner propeller area, which extends in the area of the propeller hub, is covered at least partially, in particular completely, in the expanded volume of the propeller spinner. For example, the respective surface area of the at least one propeller surface can correspond to any value between 15% and 45% of the respective propeller front surface of the at least two propeller blades. This respective percentage value is set depending on a level or category of the expansion state of the propeller spinner.

In one embodiment, it is provided that the propeller spinner is at least partially, in particular completely, made of a material which has an anisotropic elasticity, in particular the propeller spinner has at least one stiffening element on an outer side in the circumferential direction. In particular, the material of the propeller spinner has at least partially, in particular completely, an anisotropic elasticity behavior. Anisotropic elasticity behavior is to be understood as meaning that a property, in particular a material property, is direction-dependent. Thus, for example, the material which is a component of the propeller spinner can have a different elasticity behavior in a respective direction. For example, the propeller spinner can have a high elasticity in the circumferential direction and a lower bending elasticity in the axial or radial direction. Due to the high elasticity in the circumferential direction, the volume of the propeller spinner can be expanded radially. Consequently, an increase in diameter can occur in the circumferential direction. Due to the lower bending elasticity in the axial or radial direction, the propeller spinner has a defined dimensional stability. This is particularly important during a cruise flight of the aircraft, since during the flight of the aircraft high, in particular extreme, forces act on the propeller and in particular the propeller spinner arranged in front of the propeller.

In addition or instead, the propeller spinner can have at least one stiffening element or several stiffening elements on the outside of the propeller spinner in the circumferential direction. These are additional stiffening elements so that the propeller spinner has a flight-stable shape both in its basic state and in its expanded state, so that the aircraft can cruise efficiently. For example, the at least one stiffening element can consist of several sub-elements. The at least one stiffening element is arranged on the outside or outer shell of the propeller spinner, particularly when viewed in the circumferential direction. For example, the material of the propeller spinner can be glass fiber reinforced polypropylene. This has in particular different elastic moduli in two spatial directions up to a factor of about 3.

The material can also be polyurethane (TPU). This has a high level of elasticity and can be reinforced with carbon fibers (CF), for example.

For example, the propeller spinner can have a honeycomb-shaped structure, at least in some areas, which shows different elastic behavior in different spatial directions. Such a structure can be realized, for example, using an anisotropic TPU-CF material.

In a further embodiment, it is provided that a shell of the propeller spinner is designed as a paraboloid, in particular the shell of the propeller spinner can be expanded radially in a rotationally symmetrical manner about the axis of rotation. The shell of the propeller spinner is in particular the outer casing or outer casing surface of the propeller spinner.

A paraboloid is a geometric shape of a second-order surface. In particular, the shell of the propeller spinner can be designed as an elliptical paraboloid. The shell of the propeller spinner can be expanded radially in particular in order to be able to change or expand the volume of the propeller spinner. The shell is designed or arranged rotationally symmetrically around the axis of rotation and can be expanded or extended radially. This allows the volume of the propeller spinner to be changed or expanded to cover at least a partial area of the propeller front surface.

In particular, the casing can be a housing or a cover or a fairing of the propeller spinner.

In particular, the propeller spinner can be designed to be elastic.

In one embodiment, it is provided that the propeller spinner has, as an outer covering, a plurality of slats that can be adjusted by the propeller spinner adjustment device, wherein the plurality of slats are arranged in a basic state of the volume of the propeller spinner in the direction of rotation around the axis of rotation so as to overlap one another, and in order to change the volume of the propeller spinner, the plurality of slats are adjusted by the propeller spinner adjustment device such that the plurality of slats are at a predetermined distance from one another.

Specifically, the multiple slats can be automatically controlled to change the volume using the propeller spinner adjustment device and thus changed or varied. In one possible example, the propeller spinner can thus have multiple movable elements as a shell or outer covering, such as the multiple slats. Their position relative to one another can be changed in such a way that a change in the volume of the propeller spinner can be achieved.

In order to expand or increase the volume of the propeller spinner, the position or arrangement of the multiple slats is changed such that the slats are spaced further apart from one another. This is done in particular in the expanded state of the propeller spinner. In the basic state or initial state of the propeller spinner, the multiple slats are arranged so as to overlap one another. To change the volume of the propeller spinner to an expanded state, the slats are changed from their overlapping arrangement to an arrangement spaced apart from one another, so that in particular the volume of the propeller spinner expands. In particular, depending on the type or status of the expanded state, the arrangement of the slats can be varied. This can be done in particular via a mechanical connection between the coupling of the slats to the propeller spinner adjustment device. In particular, the adjustment of the slats takes place automatically or in an automated manner with the aid of the propeller spinner adjustment device.

In particular, the slats are arranged in the circumferential direction as the outer covering of the propeller spinner around the axis of rotation or are positioned tioned. In particular, the adjustment of the multiple lamellae takes place in the circumferential direction so that the lamellae, viewed in the circumferential direction, have a predetermined, in particular increased, distance from one another. For example, in the expanded state, the multiple lamellae can be arranged in such a way that the multiple lamellae no longer overlap with one another. In a possible expanded state, the multiple lamellae can be arranged at their outer edges so that they are adjacent to one another at least in some areas.

In particular, a cup-shaped outer covering or shell of the propeller spinner can be formed with the help of the multiple lamellae. In other words, the multiple lamellae can be fanned out for the expanded state of the propeller spinner.

In particular, the propeller spinner can consist of several lamellae on the outside, the volume or size of which can be varied by the relative displacement of the lamellae to one another.

In one embodiment, it is provided that the propeller spinner adjustment device is arranged in an inner region of the propeller spinner, wherein a movable adjustment element of the propeller spinner adjustment device is arranged in a front side of the propeller spinner facing away from the propeller, wherein the movable adjustment element is designed to be moved by means of the propeller spinner adjustment device to change the volume of the propeller spinner within the inner region from the side facing away from the propeller towards the propeller. In particular, the volume of the propeller spinner can be changed by means of a mechanical mechanism.

For example, the movable adjustment element can be an adjustment cone. The interior of the propeller spinner can be, for example, a hollow interior of the propeller spinner.

The movable adjustment element is arranged in particular within the interior of the propeller spinner and can be controlled to move using the propeller spinner adjustment device. In the basic state of the propeller spinner, the movable adjustment element is located on the front side of the propeller spinner facing away from the propeller, i.e. in the area of the tip of the propeller spinner. For the expanded state of the propeller spinner, the movable adjustment element can be controlled and moved in such a way that it is moved, in particular pulled, from the front side of the propeller spinner facing away from the propeller towards the propeller, i.e. the side of the propeller spinner extending towards the propeller. By moving the adjustment element from the front of the propeller spinner towards the back of the propeller spinner, a change in the volume of the propeller spinner can be brought about. Thus, with the help of a mechanical adjustment mechanism, the volume of the propeller spinner can be made to cover at least one area of the propeller front surface.

In one embodiment, it is provided that the propeller spinner adjustment device has a pneumatic adjustment unit, wherein at least one inflatable element, which is arranged in an inner region of the propeller spinner, can be controlled by means of the pneumatic adjustment unit to change the volume of the propeller spinner. This makes it very easy to adjust the volume of the propeller spinner by inflating or deflating the inflatable element. In particular, the inflatable elements are in a non-inflated or only partially inflated state in the basic state of the propeller spinner.

In the expanded state of the propeller spinner, the inflatable elements are in a partially, in particular fully, inflated state. Depending on which expansion state is intended and how much of the propeller front surface is to be covered, the inflatable elements can be variably inflated. This can be done using the propeller spinner adjustment device. In particular, at least one inflatable element or several inflatable elements can be arranged in the interior or inner area of the propeller spinner. The volume of the propeller spinner can thus be changed using a pneumatic mechanism.

In particular, the propeller spinner can be changed in its volume by pneumatic or hydraulic adjustment.

For example, the inflatable elements can be designed as inflatable rings which are arranged circumferentially in the inner region of the propeller spinner.

A further aspect of the invention relates to an aircraft with at least one aviation drive according to the previous aspect or an advantageous development thereof. According to the invention, when the aircraft is hovering, the axis of rotation of the propeller is at a predetermined angle to the vertical in a longitudinal direction of the aircraft and when the aircraft is cruising, the axis of rotation of the propeller is at a predetermined angle to the vertical in a longitudinal direction of the aircraft. The propeller's axis of rotation is aligned with the longitudinal direction of the aircraft at a predetermined angle to the horizontal.

For example, in hover flight the rotation axis of the propeller can be arranged in a value interval between ± 10% to the vertical. In cruise flight the rotation axis of the propeller can be arranged in a value interval between ± 10% to the horizontal.

Optionally, in hovering flight, the rotation axis of the propeller can be arranged perpendicular to the longitudinal direction of the aircraft. Optionally, furthermore, in cruising flight of the aircraft, the rotation axis of the propeller can be aligned parallel to the longitudinal direction of the aircraft.

In particular, the orientation of the propeller's axis of rotation may vary depending on the flight phase or flight condition of the aircraft.

For example, the aircraft can be a convertible aircraft that can take off vertically and land vertically. In particular, the aircraft can change flight modes or flight conditions during the flight. For example, the aircraft can be a vertical take-off aircraft. In particular, the aircraft can be designed as an eVTOL ("vertical take-off and landing aircraft"). In particular, the aircraft can be referred to as an air taxi.

For example, the aircraft can be part of an aircraft fleet to provide an efficient mobility solution.

In particular, the aircraft can have at least one aviation drive, in particular several aviation drives, in particular engines. For example, the aircraft can have one aviation drive according to the invention per wing or airfoil. For example, two aviation drives according to the invention can also be arranged per wing.

For example, the number of aviation engines can be based on the aircraft’s specific area of application.

In particular, the aircraft according to the invention and in particular the aviation drive according to the invention can eliminate or minimize the compromise used to describe the differences between the operating state of "hovering", i.e. without control, and forward flight, i.e. with flow. For example, the propeller can generate a usable lift in hovering flight near the hub, i.e. near the propeller hub. In cruising flight, the propeller can generate at least partially harmful downforce near the hub. This can also be the case with a variable pitch propeller. For example, with a variable pitch propeller, the entire propeller blade can be set more sharply in accordance with the higher axial flow. An angle of attack can be varied. This can be solved, for example, with the present invention.

A further aspect of the invention relates to a method for operating an aviation drive of an aircraft, wherein a propeller of the aviation drive, which is arranged on a drive shaft of the aviation drive, is driven by the drive shaft about a rotation axis of the propeller. According to the invention, the volume of a propeller spinner, which is arranged in the front area of the propeller viewed in the direction of the rotation axis of the aviation drive, is changed with a propeller spinner adjustment device depending on a position of the aviation drive in the radial direction to the rotation axis.

In particular, the method just described can be designed with an aviation engine or an aircraft according to the previous aspects or an advantageous development thereof. In particular, the aviation engine and/or the aircraft can have, in particular technical, means to carry out or execute the method just described.

In particular, the volume can be changed automatically depending on the position of the aircraft engine or the aircraft.

In particular, the position of the aircraft propulsion system can be used to characterize a flight phase or a flight mode or flight state of the aircraft. In particular, the aircraft can perform a hover flight, for example in a helicopter mode. This occurs in particular during a take-off phase and/or climb phase of the aircraft. Hovering also occurs during a descent and/or landing approach or landing of the aircraft. Hovering can be understood as a flight state in which an aircraft is in the air in an unchanged position and at an unchanged height. Furthermore, a cruise flight can be performed as a flight phase during the movement or flight of the aircraft. For example, the air flight phase between the climb after reaching the planned cruise altitude and the start of of descent. In particular, the aircraft and thus the aircraft engine are put into a cruise flight mode when, for example, a flight altitude is reached for carrying out a cruise flight.

In one embodiment of the method described above, it is provided that the volume of the propeller spinner is changed from a basic state to at least one expansion state using the propeller spinner adjustment device in such a way that a propeller front surface of the propeller is covered at least in some areas by the propeller spinner whose volume has been changed, more towards the front than in the basic state. Thus, for example, depending on the position of the aircraft drive and/or a flight phase of the aircraft, at least one of several expansion states for the propeller spinner can be automatically set, so that in particular the volume of the propeller spinner can be expanded to cover at least a partial area of the propeller front surface.

In a further embodiment of the method described above, the volume of the propeller spinner is automatically changed when the aircraft drive changes its position between a cruise position and a hover position. Furthermore, the volume of the propeller spinner can be set or changed or submitted to the expanded state in the cruise position and to the basic state in the hover position. Depending on the position of the aircraft drive and/or an operating state of the aircraft, a point in time and/or a period of time for changing the volume of the propeller spinner and/or a volume size to which the volume of the propeller spinner is changed can be determined. For example, this can be done with the help of an electronic evaluation unit of the propeller spinner adjustment device.

For example, the electronic evaluation unit can be used to determine or ascertain at what point in time and for what period of time the volume of the propeller spinner should be changed. This can be transmitted, for example, to the propeller spinner adjustment device, in particular a control unit. Furthermore, a volume size to which the volume of the propeller spinner will be brought or changed can be determined. A wide variety of information can be taken into account here. For example, an operating state of the aircraft can be a flight phase. It is particularly important whether the aircraft is in a takeoff phase or a cruise phase.

In particular, advantageous embodiments of one aspect can be viewed as advantageous embodiments of another aspect and/or all aspects. In particular, advantageous embodiments of the aviation drive can be viewed as advantageous embodiments of the aircraft and the method. Likewise, advantageous embodiments of the method can be viewed as advantageous embodiments of the aviation drive of the aircraft. This also applies in reverse.

The invention also includes further developments of the aircraft according to the invention and of the method according to the invention, which have features as have already been described in connection with the further developments of the aviation propulsion system according to the invention. For this reason, the corresponding further developments of the aircraft according to the invention and of the method according to the invention are not described again here.

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

• 1 eine schematische Darstellung eines Luftfahrzeugs mit zumindest einem Luftfahrtantrieb in einer Reiseflug-Stellung;
• 2 eine weitere schematische Darstellung des Luftfahrzeugs aus 1 in einer Schwebeflug-Stellung;
• 3 eine schematische Darstellung des Luftfahrtantriebs aus 1, wobei sich das Volumen eines Propellerspinners des Luftfahrtantriebs in einem Grundzustand befindet;
• 4 eine weitere schematische Darstellung des Luftfahrtantriebs aus 1, wobei sich das Volumen des Propellerspinners des Luftfahrtantriebs in einem Aufweitungszustand befindet;
• 5 in einer beispielhaften Seiten-Schnittdarstellung des Propellerspinners einen Mechanismus, um das Volumen (hier im Grundzustand dargestelt) des Propellerspinners zu verändern;
• 6 in einer weiteren beispielhaften Seiten-Schnittdarstellung des Propellerspinners einen Mechanismus, um das Volumen (hier im Aufweitungszutand dargestellt) des Propellerspinners zu verändern;
• 7 eine weitere schematische Darstellung des Luftfahrtantriebs aus 1, wobei hier eine spezielle Ausführungsform einer Propellerspinner-Verstelleinrichtung dargestellt ist;
• 8 in einer beispielhaften Seiten-Schnittdarstellung des Propellerspinners einen Mechanismus, um das Volumen (hier im Grundzustand dargestellt) des Propellerspinners zu verändern;
• 9 in einer weiteren beispielhaften Seiten-Schnittdarstellung des Propellerspinners einen Mechanismus, um das Volumen (hier im Aufweitungszutand dargestellt) des Propellerspinners zu verändern;
• 10 eine beispielhafte Vorderansicht des Propellerspinners, wobei dieser als äußere Verkleidung mehrere verstellbare Lamellen (hier sind sie zueinander überlappend dargestellt) aufweist;
• 11 eine beispielhafte Seitenansicht des Propellerspinners aus 10;
• 12 eine beispielhafte Vorderansicht des Propellerspinners aus 10, wobei hier die Lamellen aufgefächert sind; und
• 13 eine beispielhafte Seitenansicht des Propellerspinners aus 12.

In the following, embodiments of the invention are described.

• 1 a schematic representation of an aircraft with at least one aviation engine in a cruise position;
• 2 another schematic representation of the aircraft from 1 in a hover position;
• 3 a schematic representation of the aviation propulsion system from 1 , where the volume of a propeller spinner of the aircraft engine is in a ground state;
• 4 another schematic representation of the aviation engine from 1 , wherein the volume of the propeller spinner of the aircraft engine is in an expanded state;
• 5 in an exemplary side sectional view of the propeller spinner, a mechanism to change the volume (shown here in the ground state) of the propeller spinner;
• 6 in another exemplary side sectional view of the propeller spinner, a mechanism to change the volume (here shown in the expanded state) of the propeller spinner;
• 7 another schematic representation of the aviation engine from 1 , where a special embodiment of a propeller spinner adjustment device is shown;
• 8 in an exemplary side sectional view of the propeller spinner, a mechanism to change the volume (shown here in the basic state) of the propeller spinner;
• 9 in another exemplary side sectional view of the propeller spinner, a mechanism to change the volume (here shown in the expanded state) of the propeller spinner;
• 10 an exemplary front view of the propeller spinner, which has several adjustable slats as an outer covering (here they are shown overlapping each other);
• 11 an example side view of the propeller spinner from 10 ;
• 12 an example front view of the propeller spinner from 10 , where the lamellae are fanned out; and
• 13 an example side view of the propeller spinner from 12 .

The embodiments explained below are preferred embodiments of the invention. In the embodiments, the components described each represent individual features of the invention that are to be considered independently of one another, which also develop the invention independently of one another and are therefore to be viewed as part of the invention individually or in a combination other than that shown. Furthermore, the embodiments described can also be supplemented by other features of the invention already described.

In the figures, functionally identical elements are provided with the same reference symbols.

The 1 shows, for example, a schematic representation of an aircraft 1. For example, the aircraft 1 can be a convertible aircraft or an eVTOL. In particular, the aircraft 1 serves as a vehicle for urban air mobility. In particular, the aircraft 1 can take off and land vertically.

For example, the aircraft 1 can have two wings 2 or airfoils. So that the aircraft 1 can be operated and in particular moved, the aircraft 1 can have at least one aviation drive 3. For example, the aviation drive 3 can be referred to as the engine or drive unit of the aircraft 1. In this exemplary embodiment, the aircraft 1 has one aviation drive 3 per wing 2.

The aviation drive 3 can have a propeller 4. For example, the propeller 4 can be referred to as an airscrew. The propeller 4 is arranged, for example, on a drive shaft 5 of the aviation drive 3. With the help of this drive shaft, which can in particular be referred to as a mechanical drive, the propeller 4 can be driven about a rotation axis 6 of the propeller 4. The rotation axis 6 is the axis about which the propeller 4 rotates. For example, the rotation axis 6 can be aligned parallel to the drive shaft 5.

In particular, the aircraft 1 can enter into different flight phases. A flight phase can, for example, be a cruise flight or cruise flight phase of the aircraft 1.

In particular, the 1 the aircraft 1 is shown in cruise flight. In cruise flight, the axis of rotation 6 of the propeller 4 is aligned with a longitudinal direction 7 or longitudinal axis (corresponds to the x-axis) of the aircraft 1 at a predetermined angle to the horizontal. For example, the axis of rotation 6 and the longitudinal direction 7 can be described as essentially parallel. The position of the aircraft drive 3 can be changed for landing or taking off. Mechanical adjusting devices can be provided for this purpose. Such an operation or state of the aircraft 1 is shown in the 2 shown. Here, a hovering flight of the aircraft 1 is shown. With the hovering flight, the aircraft 1 can take off and land vertically (corresponds to the z-axis). In particular, when the aircraft 1 is hovering, the axis of rotation 6 of the propeller 4 is aligned with the longitudinal direction 7 of the aircraft 1 at a predetermined angle to the vertical. For example, as in the 2 shown, the rotation axis 6 can be considered essentially perpendicular to the longitudinal direction 7.

Back to 1 . Furthermore, the aviation drive 3 can have a propeller spinner or spinner 8, in particular as an aerodynamic precaution. The propeller spinner 8 can be arranged in the front area 10 of the propeller 4, viewed in the direction 9 of the axis of rotation 6 of the aviation drive 3. In particular, the direction 9 of the axis of rotation 6 in the cruise flight of the aircraft 1 can be the same as the direction 11 of the longitudinal direction 7.

Thus, for example, the propeller spinner 8 can be referred to as the front cap or tip of the propeller 4. In particular, as shown in the 1 As can be seen, the propeller spinner 8 is designated at the front of the aircraft drive 3 with respect to the direction 10.

In the hovering flight of aircraft 1 (compare 2 ), the direction 9 of the rotation axis 6 and the direction 11 of the longitudinal direction 7 can be substantially perpendicular.

In the 3 A schematic representation of the aircraft engine 3 is shown.

Since negative properties can occur, particularly during cruise flight of the aircraft 1, which can be caused, for example, by the propeller 4, the aviation drive 3 can have a propeller spinner adjustment device 12. This is an automatic, electromechanical adjustment device. In particular, this can be an electromechanical system. For example, a separate propeller spinner adjustment device 12 can be provided for each aviation drive 3. It is also conceivable that a central propeller spinner adjustment device is provided, with which all aviation drives 3 of the aircraft 1 can be controlled and/or regulated. In particular, the propeller spinner adjustment device 12 can be referred to as a control unit.

In particular, the volume of the propeller spinner 8 can be changed in a defined manner in the radial direction 13 to the rotation axis 6 using the propeller spinner adjustment device 12. This means that, for example, the volume of the propeller spinner 8 can be reduced or increased. In particular, the propeller spinner adjustment device 12 can be used to automatically expand or widen the propeller spinner 8 radially. For example, the volume of the propeller spinner 8 can be changed or adjusted depending on a position of the aircraft drive 3 and/or a flight phase of the aircraft 1.

For example, by means of the propeller spinner adjustment device 12, the volume of the propeller spinner 8 can be adjusted from a basic state (this is shown in the 3 to see) into at least one expansion state (this is in the 4 In particular, the volume in the expanded state (see 4 ) is expanded or enlarged compared to the ground state. In the 4 As already mentioned, one possible expansion state of various expansion states of the volume of the propeller spinner 8 is shown. In particular, the volume of the propeller spinner 8 can be changed in such a way that a propeller front of a propeller front surface 14 of the propeller 4 is at least partially covered by the propeller spinner 8 with its volume changed. In particular, the propeller 8 is covered towards the front (viewed with respect to the direction 9 of the axis of rotation 6). In other words, the front area 10 of the propeller 4 can be covered at least partially. In particular, the changed volume 8 in the expansion state can cover areas of the propeller 4 which generate a negative thrust or an efficiency-reducing downforce. This makes it possible to achieve more efficient cruising flight, so that in particular an increased range of the aircraft 1 can be achieved.

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

In the enhanced state, the propeller spinner 8 can cover or shade the propeller front surface 14 at least in part, in particular completely, with a side 15 of the propeller spinner 8 facing the propeller 4. In particular, at least one radially inner partial surface 16 of the propeller front surface 14 with respect to the rotation axis 6 of the propeller 4, which extends radially outward from the rotation axis 6, can be covered by the propeller spinner 8 in its radially expanded expanded state. In particular, the inner partial surface 16 extends from the rotation axis 6 in the radial direction 13. In particular, in the expanded state, the inner partial surface 16 is expanded in comparison to the basic state (cf. 3 ) radially further covered. Furthermore, in 4 It can be seen that a rear end 17 of the propeller spinner 8 facing the propeller 4 is radially expanded in the expanded state compared to the basic state. In particular, it is further expanded or extended with respect to the radial direction 13. In particular, the rear end 17 is at the opposite end of the propeller spinner 8 with respect to the direction 9.

For example, the propeller 4 has at least two propeller blades 19, 18. Optionally, the propeller 4 can have several propeller blades 18, 19. The propeller blades 18, 19 are connected or mechanically coupled to the drive shaft 5 at a connection point 20 of the propeller 4. The connection point 20 can in particular be the center of the propeller 4. In particular, the Connection point 20 around a propeller hub or rotor hub. For example, a rotation axis 6 can run through the middle of the connection point 20 so that the connection point 20 can also be rotated symmetrically about the rotation axis 6. For example, the connection point 20 can be connected to the drive shaft 5 along the rotation axis 6 in order to provide the propeller 4 and in particular the propeller blades 18, 19 with rotation depending on a speed.

For example, a respective surface area 21, 22 of the at least two propeller blades 18, 19 can be covered at least in part by the propeller spinner 8, the volume of which is changed by the propeller spinner adjustment device 12, at the front with respect to the front area 10. For example, the two surface areas 21, 22 form the inner partial area 16.

In particular, the respective surface area 21, 22 extends towards the connection point 20 and away from a respective radial end area 23, 24 of the at least two propeller blades 18, 19. The respective surface area 21, 22 can thus be located near the center of the connection point 20 and in particular near the center of the propeller 4.

In particular, the respective surface area 21, 22 can correspond to at least 20 percent, in particular 30 percent, in particular 40 percent of a respective propeller front surface 14 of the at least three propeller blades 18, 19. Thus, for example, the inner propeller area of the propeller 4 can be covered. For example, a respective surface area 21, 22 can correspond to a third, in particular a quarter, of a front surface of a respective propeller blade 18, 19.

In particular, by means of the propeller spinner 8, which has a modified volume, one third, in particular one quarter, of the propeller front surface 14 can be covered in an expanded state.

For example, the propeller spinner 8 can be formed at least partially, in particular completely, from a material which has anisotropic elasticity. The propeller spinner 8 can, for example, have at least one stiffening element 26 on an outer side 27 in the circumferential direction 25 (see 8 ). In particular, the at least one stiffening element 26 is a stabilizing element to improve the stability of the propeller spinner 8, in particular during cruising flight. In particular, the propeller spinner 8 can have a plurality of stiffening elements 26.

For example, the propeller spinner 8 can have a casing 28 (compare 1 ). This casing 28 can be referred to, for example, as a jacket or outer casing. In particular, the casing 28 can be designed as a paraboloid. Thus, the casing 28 and in particular the propeller spinner 8 have a parabolic shape. In particular, the casing 28 can be radially expanded in a rotationally symmetrical manner about the rotation axis 6, so that the volume of the propeller spinner 8 can be changed.

In particular, the 5 a possible embodiment or mechanism for changing the volume of the propeller spinner 8. For this purpose, for example, the propeller spinner adjustment device 12 can be arranged in an inner region 29 or cavity of the propeller spinner 8. A movable adjustment element 30 of the propeller spinner adjustment device can be arranged in a front side 31 facing away from the propeller 4 (with respect to the direction 9 of the rotation axis 6). In the 5 In particular, the basic state of the propeller spinner 8 and in particular of the movable adjustment element 30 is shown. In the 6 at least one expansion state of the propeller spinner 8 is now shown. The basic state is visualized again with the dashed lines 32. The movable adjustment element 30 is now moved by means of the propeller spinner adjustment device 12 to change the volume within the inner area 29 from the front 31 towards the propeller 4. For this purpose, the movable adjustment element 30 can be moved in the direction (opposite the direction 9) of the propeller 4, for example by means of a spindle 33. In particular, the adjustment element 30 is moved towards a counter element 34. This movement within the propeller spinner 8 can cause an expansion or change in the volume.

In the 7 Another possibility for changing the volume is shown. For example, the propeller spinner adjustment device 12 can be arranged outside the propeller spinner 8. This can be done, for example, in an area of the propeller 4 facing away from the direction 9. However, in contrast to the design in 6 the spindle 33 or threaded spindle is arranged outside, in particular completely outside, the propeller spinner 8. For this purpose, the propeller spinner adjustment device 12 can, for example, have an electric motor 35. The electric motor 35 can, for example, have a housing 36, a stator 37, a rotor 38 and a hollow shaft 39. Furthermore, shaft bearings 40 can be provided. An adjustment actuator 41 can in turn be provided for adjusting the movable adjustment element 30. This can be operated using the electric motor 35. In particular, the adjustment actuator 41 can be arranged inside the propeller spinner 8. For this purpose, for example, cable guides can be provided. In particular, the electric motor 35 has a cooling air guide 42.

In particular, the 7 The propeller spinner 8 shown may be a non-rotating spinner.

In the 8 A further possibility for changing the volume is shown. The propeller spinner adjustment device 12 can have a pneumatic or hydraulic adjustment unit 43. This adjustment unit 43 can be arranged in particular in the inner region 29 of the propeller spinner 8. With the help of the pneumatic adjustment unit 43, which can be controlled and/or regulated by the adjuster spinner adjustment device 12, at least one inflatable element 44, which is arranged in the inner region 29, can be controlled. In order to change the volume, in particular to expand the volume, the inflatable elements can be inflated. In particular, in the 8 The basic state of the propeller spinner 8 is shown again.

In the 9 In turn, a state of expansion is shown. In the 9 the at least one inflatable element 44, for example an inflatable ring, is inflated, in particular filled with air or a gas, so that the volume of the propeller spinner 8 expands. In particular, the inflatable element 44 can be controlled using the pneumatic adjustment unit 43. On the one hand, this can be inflated or deflated again, depending on the volume requirements of the propeller spinner 8.

In the following 10 to 13 Another possibility for changing the volume of the propeller spinner 8 is shown.

For example, the 10 a front view of the propeller spinner 8 viewed from the front area 10.

In this case, for example, the propeller spinner 8 can have, as an outer covering 45, several slats 46 that can be adjusted by the propeller spinner adjustment device 12. 10 The initial state 32 of the propeller spinner 8 is shown again. In the basic state or initial state 32, the lamellae 46 are arranged overlapping one another in the circumferential direction 25 or the direction of rotation around the rotation axis 6. For this purpose, for example, in the 11 a side view is shown.

To change the volume 8, the slats 46 can be adjusted or changed so that the slats 46 in particular are fanned out. This is now done in the 12 The slats 46 are controlled, in particular by means of the propeller spinner adjustment device 12, so that they are fanned out. The volume is thus expanded radially. This is shown in the 12 between the comparison to the basic state 32. The multiple slats 46 are controlled or adjusted so that the multiple slats 46 have a predetermined distance 47 from each other. This is the case, for example, in 13 Thus, the volume of the, in particular elastic, propeller spinner 8 can be expanded or increased by the now spaced slats 46.

In one embodiment of the invention, in particular the volume of the propeller spinner 8 can be automatically changed with the propeller spinner adjustment device 12 depending on a position of the aircraft drive 3 and/or a flight phase of the aircraft 1 in the radial direction 13 to the axis of rotation 6. The volume of the propeller can thus be adjusted on the system side by electro-mechanical systems.

Furthermore, for example, with the aid of the propeller spinner adjustment device 12, the volume of the propeller spinner 8 can be changed from the basic state 32 to at least one expanded state such that the propeller front surface 14 of the propeller 4 is at least partially covered by the propeller spinner 8, whose volume has been changed, to a greater extent than in the basic state 32. This can also be done by an automated system, in particular a control and/or regulating device.

Furthermore, for example, the volume of the propeller spinner 8 can be changed automatically when the aircraft engine 3 changes its position between a cruise position (compare 1 ) and a hover position (compare 2 ). For example, the propeller spinner adjustment device 12 can have an electronic evaluation unit (see 3 ). In particular, the volume of the propeller spinner 8 can be set to the expanded state in the cruise position and to the basic state in the hover position. Depending on the respective position of the aircraft drive and/or the operating state of the aircraft 1, a time and/or a period of time for changing the volume of the propeller spinner 8 and/or a volume size by which the volume of the propeller spinner 8 is changed can be determined. This can be done by means of the electronic evaluation unit or wise computing unit 48 and transmitted to the respective units.

For example, the propeller spinner 8 can have a shape memory alloy with which the shape of the propeller spinner 8 can be changed. For example, the control or controls for changing the volume of the propeller spinner 8 can be carried out by means of piezoelectric controls or centrifugal force-controlled controls.

list of reference symbols

1

aircraft

2

wing

3

aviation propulsion

4

propeller

5

drive shaft

6

axis of rotation

7

longitudinal direction

8

propeller spinner

9

direction of the rotation axis

10

front area of the propeller

11

direction of the aircraft's longitudinal direction

12

propeller spinner adjustment device

13

radial direction

14

propeller front surface

15

side of the propeller spinner facing the propeller

16

inner surface of the propeller front surface

17

rear end of the propeller spinner

18, 19

propeller blades

20

connection point

21, 22

surface areas

23, 24

radial end areas

25

circumferential direction

26

stiffening element

27

outside

28

Covering

29

interior

30

adjustment element

31

front of the propeller spinner

32

ground state

33

spindle

34

counter element

35

electric motor

36

housing of the electric motor

37

stator of the electric motor

38

rotor of the electric motor

39

hollow shaft

40

shaft bearings

41

adjustment actuator

42

cooling air duct

43

pneumatic adjustment unit

44

inflatable element

45

outer cladding

46

several slats

47

distance between the slats

48

electronic evaluation unit

Claims (15)

Aviation drive (3) for an aircraft (1), comprising: - a propeller (4) which is arranged on a drive shaft (5) of the aviation drive (3) and can be driven by means of the drive shaft (5) about a rotation axis (6) of the propeller (4), - a propeller spinner (8) which is arranged in the front region (10) of the propeller (4) viewed in the direction (9) of the rotation axis (6) of the aviation drive (3), characterized by - a propeller spinner adjustment device (12) for the defined change of the volume of the propeller spinner (8) in the radial direction (13) to the rotation axis (6), wherein the volume of the propeller spinner (8) can be changed in the radial direction (13) from a basic state to at least one expansion state using the propeller spinner adjustment device (12) such that a propeller front surface (14) of the propeller (4) is at least partially influenced by the Volume changed propeller spinner (8) is covered more towards the front than in the basic state. Aviation propulsion (3) after claim 1 , characterized in that the propeller spinner (8) covers the propeller front surface (14) at least in regions with a side (15) of the propeller spinner (8) facing the propeller (4). Aviation propulsion (3) after claim 2 , characterized in that at least one with respect to the axis of rotation (6) of the propeller (4) radially inner partial surface (16) of the propeller front surface (14), which extends radially outward from the axis of rotation (6), is covered by the propeller spinner (8) in its radially expanded state, in particular is covered radially more than in the basic state. Aviation propulsion (3) after claim 2 or 3 , characterized in that a rear end (17) of the propeller spinner (8) facing the propeller (4) is radially expanded in the expanded state compared to the basic state. Aviation drive (3) according to one of the preceding claims, characterized in that 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 a respective surface region (21, 22) of the at least two propeller blades (18, 19), which extends towards the connection point (20) and away from a respective radial end region (23, 24) of the at least two propeller blades (18, 19), is covered at the front at least in regions by the propeller spinner (8), the volume of which is changed by the propeller spinner adjustment device (12). Aviation propulsion (3) after claim 5 , characterized in that the respective surface area (21, 22) of the at least two propeller blades (18, 19) corresponds to at least 20%, in particular 30%, in particular 40%, of a respective propeller front surface (14) of the at least two propeller blades (18, 19). Aviation drive (3) according to one of the preceding claims, characterized in that the propeller spinner (8) is at least partially, in particular completely, formed from a material which has anisotropic elasticity, in particular the propeller spinner (8) has at least one stiffening element (26) on an outer side (27) in the circumferential direction (25). Aviation drive (3) according to one of the preceding claims, characterized in that a casing (28) of the propeller spinner (8) is designed as a paraboloid, in particular the casing (28) of the propeller spinner (8) can be expanded radially in a rotationally symmetrical manner about the axis of rotation (6). Aviation drive (3) according to one of the preceding claims, characterized in that the propeller spinner (8) has, as an outer covering (45), a plurality of slats (46) which can be adjusted by the propeller spinner adjustment device (12), wherein the plurality of slats (46) are arranged in a basic state of the volume of the propeller spinner (8) in the circumferential direction (25) about the axis of rotation (6) so as to overlap one another, and in order to change the volume of the propeller spinner (8), the plurality of slats (46) are adjusted by the propeller spinner adjustment device (12) such that the plurality of slats (46) are at a predetermined distance (47) from one another. Aviation drive (3) according to one of the preceding claims, characterized in that the propeller spinner adjusting device (12) is arranged in an inner region (29) of the propeller spinner (8), wherein a movable adjusting element (30) of the propeller spinner adjusting device (12) is arranged in a front side (31) of the propeller spinner (8) facing away from the propeller (4), wherein the movable adjusting element (30) is designed to be moved by means of the propeller spinner adjusting device (12) to change the volume of the propeller spinner (8) within the inner region (29) from the side (31) facing away from the propeller (4) towards the propeller (4). Aviation engine (3) according to one of the preceding Claims 1 until 9 , characterized in that the propeller spinner adjusting device (12) has a pneumatic adjusting unit (43), wherein by means of the pneumatic adjusting unit (43) at least one inflatable element (44), which is arranged in an inner region (29) of the propeller spinner (8), can be controlled to change the volume of the propeller spinner (8). Aircraft (1) with at least one aviation engine (3) according to one of the preceding Claims 1 until 11 , characterized in that in a hovering flight of the aircraft (1) the axis of rotation (6) of the propeller (4) is aligned with a longitudinal direction (7) of the aircraft (1) at a predetermined angle to the vertical and in a cruising flight of the aircraft (1) the axis of rotation (6) of the propeller (4) is aligned with the longitudinal direction (7) of the aircraft (1) at a predetermined angle to the horizontal. Method for operating an aviation drive (3) of an aircraft (1), wherein a propeller (4) of the aviation drive (3), which is arranged on a drive shaft (5) of the aviation drive (3), is driven by the drive shaft (5) about a rotation axis (6) of the propeller (4), characterized in that - the volume of a propeller spinner (8), which is arranged in the front region (10) of the propeller (4) viewed in the direction (9) of the rotation axis (6) of the aviation drive (3), is changed with a propeller spinner adjusting device (12) depending on a position of the aviation drive (3) in the radial direction (13) to the rotation axis (6). procedure according to claim 13 , characterized in that the volume of the propeller spinner (8) is changed from a basic state to at least one expanded state by the propeller spinner adjustment device (12) in such a way that a propeller front surface (14) of the propeller (4) is covered at least in some areas by the propeller spinner (8) whose volume has been changed to a greater extent than in the basic state. procedure according to claim 14 , characterized in that the volume of the propeller spinner (8) is automatically changed when the aviation drive (3) experiences a change in its position between a cruising position and a hovering position, in particular the volume of the propeller spinner (8) is set to the expanded state in the cruising position and to the basic state in the hovering position, in particular depending on the position of the aviation drive (3) and/or on an operating state of the aircraft (1), a point in time and/or a duration for changing the volume of the propeller spinner (8) and/or a volume size to which the volume of the propeller spinner (8) is changed is determined.

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