DE102019115578A1 - Aircraft with ducted propeller drive - Google Patents

Abstract

The invention relates to an aircraft (1) and a method for operating an aircraft (1), in particular an aircraft with wings (11, 12), with a fuselage (10) for receiving at least one pilot and / or a payload, in particular air freight and / or at least one passenger and with at least one ducted propeller drive (14). This has a propeller (20) with a hub body (21) and a plurality of blades (22) evenly distributed around the outer circumference of the hub body (21), which are invariably connected to the hub body (21), the propeller ( 20) is rotatable about a drive axis (A) and this drive power is supplied via a drive shaft (28) arranged essentially radially to the hub body (21) of the propeller (20). Furthermore, the ducted propeller drive (14) has a casing (36) which extends coaxially around the drive axis (A) of the propeller (20) and which accommodates the propeller (20) and which, in particular, interacting with the hub body (21), has a variable outlet cross section ( 15) of the ducted propeller drive (14) is defined on a drive jet outlet side (16).

Description

The invention relates to an aircraft with a fuselage and at least one ducted propeller drive with a propeller, which has a hub body and a plurality of blades evenly distributed around the outer circumference of the hub body, which is rotatable about a drive axis and coaxially about the drive axis of the propeller extending casing housing, which receives the propeller, and in particular cooperating with the hub body defines an outlet cross section of the ducted propeller drive.

Such aircraft with at least one ducted propeller drive are known and are suitable for use as air taxis or air taxis, which operate between airports up to about 1500 km apart, and are particularly suitable for flight distances of about 300 to 500 km. In particular, they can at least partially replace car and rail traffic and thus relieve the burden on roads and the rail network. The present invention is particularly suitable for such air taxis, but without being limited thereto.

Today's aircraft, especially air taxis or air taxis, emit a lot of noise. These emissions are particularly pronounced in the start-up phase. In particular, people bordering the airport, but also the occupants of the aircraft, such as the pilot and passengers, are burdened. Today's small aircraft are mostly operated with a free-moving propeller, which is the greatest source of noise. Other sources of noise besides the propeller are the internal combustion engine and the noise around the airflow.

Furthermore, aircraft drives based on propellers or ducted propellers are usually designed for a specific operating point at which the inflow in combination with the speed results in an ideal angle of attack for the rotor blade. If the airspeed changes, the angle of attack must be adjusted. This is particularly important when take-offs are quick and quiet and high flight speeds are to be achieved efficiently. The speed is usually fixed by the drive device. Therefore, the adjustment of the angle of attack on the propeller is achieved by adjusting the propeller or rotor blades (turning around their vertical axis). However, this is structurally complex and can therefore only be used for a very small, in particular single-digit, number of rotor blades.

One object of an embodiment of the present invention is to improve an aircraft or its operation and in particular to reduce its noise emissions.

This object is achieved by an aircraft with the features of claim 1 or with a method with the features of claim 22. Advantageous embodiments of the invention are the subject of the dependent claims.

To achieve the object, an aircraft, in particular an aircraft with wings, is proposed with a fuselage for receiving at least one pilot and / or a payload, in particular air freight and / or at least one passenger, and with at least one ducted propeller drive. The ducted propeller drive has a propeller which has a hub body and a plurality of rotor blades which are uniformly distributed around the outer circumference of the hub body and which are invariably connected to the hub body. The propeller can be rotated about a drive axis. Drive power is supplied to the propeller via a drive shaft arranged essentially radially to the hub body of the propeller.

The ducted propeller drive also has a casing extending coaxially around the drive axis of the propeller, which accommodates the propeller and which, in particular, interacting with the hub body, defines an outlet cross section of the ducted propeller drive on a drive jet outlet side. It is proposed that the hub body on the drive jet outlet side of the ducted propeller drive has an axially displaceable central body with a changing cross-section, in particular tapering on the drive jet outlet side, so that the outlet cross section of the ducted propeller drive can be adjusted by axially displacing the central body.

According to one embodiment of the present invention, the aircraft has at least one fuselage which is suitable for accommodating payload, which in one embodiment comprises air cargo and / or a pilot and / or several, preferably at most 10, in particular at most 4, passengers. The present invention can be used, for example, as an air (passenger and / or cargo) taxi, but is not limited thereto.

Additionally or alternatively, one embodiment of the fuselage is suitable for receiving at least one pilot who controls the aircraft manually. As a result, in one embodiment (flight) safety can be increased and / or travelers can control the aircraft themselves. In another embodiment, the aircraft is a pilotless or (purely) automatically controlled, in particular autonomous (flying) aircraft. As a result, in one embodiment the load transport can be improved and / or weight and / or installation space can be reduced or better used, which in particular also Result in cost reductions. In one embodiment, the aircraft is an aircraft with in particular (fixed) wings. The present invention can be used with particular advantage for aircraft, in particular small aircraft, without, however, being restricted thereto.

According to one embodiment of the present invention, the aircraft has at least one ducted fan drive, which is provided for driving or moving the aircraft, in particular in the air.

The ducted propeller drive has a propeller (“fan”), which has a hub body and a large number of blades evenly distributed around the outer circumference of the hub body, which are invariably connected (“fixed pitch”) to the hub body. A multiplicity of, for example, seven to fifteen rotor blades distributed around the circumference of the hub body improves the noise emission of a ducted propeller drive by changing and in particular reducing the development of tonal and noisy broadband noises with a suitable number of rotor blades. In particular, the design of the rotor blades can be optimized to operate with a substantially constant speed of rotation with little noise over the entire operating range of the ducted propeller drive. A low-noise design can also be supported by an essentially constant speed of the propeller, since the emitted frequencies depend on its speed. An essentially constant rotational speed leads to essentially constant frequency bands of the ducted propeller drive.

The propeller and in particular the part of the hub body provided with the rotor blades can be rotated or driven about a drive axis, whereby an air mass flow flowing through the ducted propeller drive can be accelerated and consequently compressed, in particular in order to generate a thrust that drives the aircraft. It is proposed to supply drive power to the ducted propeller drive, that is to say in particular to the propeller, via a drive shaft which is arranged essentially radially to the hub body of the propeller. Essentially radial to the hub body means that a longitudinal or rotational axis of the drive shaft does not necessarily have to be arranged perpendicular to the rotational or drive axis of the propeller, but can include an angle deviating from 90 ° with it. By transmitting the drive power via a drive shaft to the ducted propeller drive, a spatial separation between the drive device and the propulsion generation on the ducted propeller drive and thus, for example, a soundproof accommodation of the drive device is possible. To convert a drive power supplied to the ducted propeller via the drive shaft, a transmission device can be provided which is arranged, for example, in the hub body of the propeller. A suitable drive device, which makes the drive power available, can in particular be arranged in the fuselage or the wings of the aircraft. Because the ducted propeller drive is supplied with drive power, in particular spatially separated from the outside, the air mass flow accelerated by the propeller does not contain any combustion air, so that the proposed aircraft is driven by the ducted propeller drive described by a so-called cold air mass flow.

The proposed ducted propeller drive also has a jacketed housing which extends coaxially around the drive axis of the propeller and which receives the propeller. In particular, the casing has a larger axial extent than is necessary to accommodate propeller blades and in particular a guide device in order to form the air mass flow flowing through the ducted propeller drive, in particular aerodynamically and / or acoustically favorable. The jacket housing focuses the sound in the axial direction and thus isolates it from the radial surroundings of the jacket propeller drive, and thus in particular from the ground and the cabin, where it is perceived as annoying. In an advantageous embodiment, the inner surfaces of the jacket housing are designed in a fluidically and acoustically favorable manner and / or the outer surfaces of the jacket housing have a fluidically and acoustically favorable design. An acoustically favorable design can be designed, for example, in the form of a long, divergent inlet diffuser. A smaller sound outlet opening is also connected to the air inlet opening that is smaller as a result.

On the drive jet outlet side, the casing, in particular interacting with the hub body, defines an outlet cross-section of the casing propeller drive. The size of the outlet cross-section is used to determine the flow or exit speed of the air mass flow that is compressed in the casing and flowing out through the outlet cross-section. It is proposed that the hub body of the ducted propeller have an axially displaceable central body on the drive jet outlet side with a changing cross section, in particular tapering on the drive jet outlet side. The cross-section of the central body can vary over its axial extent in a suitable manner in order to influence the air mass flow, in particular in the area of the outlet cross-section, and to adapt it as a function of the respective flight phases. So can Central bodies, for example, be conical at least in sections in one and / or the other direction, or also - also at least partially - have a taper or radial expansion formed by an axial rounding. With the help of the changing cross section of the central body, the outlet cross section present on the drive jet outlet side of the ducted propeller drive and the air mass flow of the ducted propeller drive can be adjusted via the axial position of the central body. The adjustable outlet cross-section enables throttling and de-throttling of the propeller in the entire operating range. The angle of attack of the rotor blades can thus be controlled without the rotor blades having to be adjusted for this purpose. This enables the thrust to be adapted to the thrust requirement even at constant speed and even at high airspeed.

In interaction with the drive power transmitted to the propeller and the air mass flow accelerated by it, the drive power of the aircraft can be controlled or regulated.

The proposed embodiment can improve the efficiency and / or noise emissions of the aircraft, which is important in particular for air taxis that take off or land near settlements, cities and communities and / or have low cruising altitudes in the range of, for example, about 3000 meters is. Thus, an acoustically favorably designed ducted propeller drive having a large number of rotor blades and in particular operated at essentially constant speed, to which drive power is supplied from the outside and which has an axially displaceable central body, enables an advantageous solution for controlling or regulating the drive power of an aircraft with the special advantage of minimizing noise.

In one embodiment of the aircraft, a displacement device for axially displacing the central body is arranged in the hub body of the propeller. This is particularly advantageous if drive power is supplied to the propeller via a drive shaft and this thus compresses a cold air mass flow. The thermal load on adjusting or displacement devices required on the central body is therefore low. In various designs, the central body can be axially displaced in several stages or continuously. For such adjusting or shifting devices, various adjusting or shifting mechanisms are possible. In addition to purely axial mechanisms, for example along one or more axial guides, spindle bodies can also be used, in which case, in addition to an essentially axial displacement of the displacement body, a rotation of the displacement body about the displacement axis is also possible.

In one embodiment of the aircraft, the outlet cross-section on the drive jet outlet side of the ducted propeller drive is in a range from 0% to 50%, in particular in a range from 0% to 30% and in particular in a range, by axially shifting the central body in relation to a position with maximum opening can be reduced from 0% to 20%. In this way, the angle of attack of the blading, thus the power conversion at the propeller and thus the drive jet and thrust, can be adjusted according to the respective operating phases of the aircraft and in particular to adapt the desired flight performance.

In one embodiment of the aircraft, the jacket housing accommodates a multiplicity of guide vanes distributed around the inner circumference of the jacket housing. In addition to the effect on the air mass flow and the degree of compression achieved, the number, arrangement and design of the guide vanes also have a major influence on the generation of noise in the ducted propeller drive. In particular, suitably designed guide vanes can also take over structural functions of the ducted propeller drive, such as accommodating bearing struts or a radially arranged drive shaft. Furthermore, by arranging the guide vanes at varying distances in the ducted propeller drive, tonal noise can be reduced.

The guide vanes distributed around the inner circumference of the casing are fixedly arranged on the casing. A fixed arrangement of the guide vanes on the casing allows, for example, an integration of a drive shaft supplying drive power to the propeller in the plane of the guide vanes or enables or simplifies the mounting of the propeller within the casing. Struts usually required for this purpose, which additionally impair the air flow and in particular have negative acoustic effects, can be omitted or at least reduced.

In one embodiment of the aircraft, the propeller and in particular the geometry of the rotor blades and / or the guide vanes and / or the casing is set up to be operated over the entire operating range of the ducted propeller drive at a substantially constant speed, which is in a range from 1,500 to 5,000 U / min, in particular in the range from 2,000 to 4,000 rpm and in particular at about 2,600 rpm. In a design of the ducted propeller drive which is provided for operation at a substantially constant speed, the Geometric design of the propeller and in particular the rotor blades and / or the guide vanes and / or the casing for this essentially constant speed, in particular with regard to fluidic and acoustic requirements, can be designed favorably in order to reduce noise and make the ducted propeller drive energy-efficient.

It goes without saying that the speed of the propeller cannot be kept exactly constant from take-off to landing of an aircraft, since the speed control results in unavoidable speed fluctuations depending on the flight conditions and the drive torque acting on the propeller. For example, changes in flight conditions such as changes in airspeed, adapting acceleration and / or deceleration, idling or a transition before and / or after a climb or descent, cause speed fluctuations. Apart from such external influences, which require an “essentially” constant speed, the propeller of the proposed aircraft should be operated at a constant speed or the speed should be regulated to a correspondingly constant value, which in particular enables comparatively low noise emissions. Possible deviations are in particular in a range of +/- 10%.

In one embodiment of the aircraft, a gear for transmitting the drive power from the drive shaft to the propeller is arranged in the hub body of the propeller, which gear can also be used in particular to increase or reduce a drive speed of the drive device. Depending on the design of the drive device, it is operated at a speed that deviates from the intended speed of the propeller. Accordingly, it is proposed to increase or reduce the speed of the drive device in one embodiment by means of a gear, which can be arranged for example in the hub body of the propeller or at another position in the drive train. The arrangement of a gear in the hub body of the propeller for converting a radially supplied drive power into rotational energy acting around the drive axis of the propeller enables a compact design of the ducted propeller drive.

In one embodiment of the aircraft, at least one drive device providing drive power to the ducted propeller drive is arranged in the fuselage and / or in at least one wing of the aircraft, in particular in a soundproofed manner. The arrangement of a drive device, which in particular generates tonal or broadband noise, in the fuselage and / or in at least one wing of the aircraft has the advantage that the drive device itself in the fuselage and / or in at least one wing is designed to be sound-absorbing or sound-insulating, in particular encapsulated can and / or the fuselage and / or the at least one wing can be designed or configured to be sound-absorbing or sound-insulating in order to attenuate or isolate the drive noise of the drive device. In this way, the noise that is perceptible outside the aircraft can be significantly reduced.

In one embodiment of the aircraft, the drive device of the ducted propeller drive has a control device and is set up, by adapting the output drive power and interacting with an axially displaceable central body, the speed of the propeller of the ducted propeller drive regardless of the respective power requirement during a flight, in particular in favor of lower noise emissions To keep it essentially constant. Correspondingly, the drive device is designed not to meet a power requirement by varying the drive speed, but to represent the required power by adapting the output torque, in particular in conjunction with an axial displacement of the central body and the resulting change in the outlet cross-section at the same speed. This takes place in particular in conjunction with a corresponding power consumption of the ducted propeller drive, which can be adapted via the outlet cross section on the drive jet outlet side of the ducted propeller drive.

In one embodiment of the aircraft, the drive device has at least two drive machines that can be operated in parallel to drive a ducted propeller drive. Such a drive device initially advantageously has a redundancy in the event of failure of one of the two drive machines, the failed drive machine in particular being separable from the drive train, which can be done for example by means of a clutch. It is also possible to use a first drive machine as the “main drive machine”, which provides the basic load of the drive power, so to speak, and to provide a second drive machine as an additional, parallel drive in the event of power requirements that go beyond the power range of the first drive machine. For example, in one embodiment the first drive machine can be designed as an internal combustion engine, such as a piston engine and / or a gas turbine and in particular (each) with liquid fuel, in one embodiment the piston engine with gasoline or diesel and the gas turbine with kerosene, methane, hydrogen or the like are operated. As Second drive machine can be provided, for example, an electrical machine which can be supplied with electrical energy, for example, from an accumulator.

In one embodiment of the aircraft, the first drive machine is set up to operate the ducted propeller drive in a first operating range, the power requirement of which goes beyond the cruising performance, the power of the first drive machine increasing up to 1.5 times, in particular up to 1.8 -fold and in particular up to twice the performance of a cruise performance. A drive machine designed in this way thus covers a large spectrum of the drive power required during a flight or the power requirement during a large part of the flight duration. In particular in the case of aircraft with low maximum take-off weights and correspondingly low cruising performance, this enables the use of comparatively small, energy-efficient drive machines, such as piston engines.

In one embodiment of the aircraft, a second drive machine is set up to operate the ducted propeller drive parallel to the first drive machine in a second operating range, the power requirement of which is over 1.5 times, in particular over 1.8 times and in particular over twice the power a cruise performance. Due to the additional power of the second drive machine, the drive device of the aircraft can meet a power requirement that goes beyond the power range of the first drive machine. The first and second drive machines can be operated in parallel, so that their respective power output essentially adds up. In this embodiment, it is possible to provide the first drive machine with a power range below the peak power required in particular when the aircraft takes off, since an additional power requirement is made available by the second drive machine operated in parallel.

In one embodiment of the aircraft, the first drive machine can be operated in a characteristic map area with favorable energy consumption and / or lower noise emissions and / or in a map area in which the power output of the first prime mover is increased. Thus, by means of a variable power output of the second drive machine, the power output of the first drive machine can be kept at least essentially constant in a suitable manner, in particular in a particularly favorable power range of the first drive machine. Such a favorable power range or map area with favorable energy consumption results, for example, from the consumption map (so-called shell diagram) of an internal combustion engine. The second drive machine compensates in particular for the power requirement of the aircraft, which goes beyond operating the first drive machine in a favorable power range (torque at a certain speed).

As a result of this so-called “boosting” the power output of the drive device, the first drive machine can also be operated in a power range that is favorable for this when there is an increased power requirement. The second drive machine "pushes" the first drive machine into the favorable power range in the characteristic map, in that the second drive machine delivers the differential power required to achieve the required drive power. In addition, this embodiment has the advantage that the power output of the first drive machine - depending on its design - is higher in certain map areas than in others, which means that the second drive machine “boosts” or “pushes” the first drive machine into a corresponding map area Drive machine can be used to further increase the efficiency of the drive device. In particular, such a drive device can provide a high drive power for a short time in particular, which enables high rates of climb, particularly in the starting phase. The noise pollution on the ground can also be further reduced through high rates of climb and thus a rapid gain in flight altitude.

In particular, the second drive machine as a booster can temporarily increase the drive power in the case of increased requirements, in particular when the aircraft is started. As a result, in one embodiment, the rate of climb and / or short take-off capability of the aircraft can be increased and in particular the use as an air taxi and / or the noise emission of the aircraft can be (further) improved, in particular by quickly moving away from the airfield. Additionally or alternatively, in one embodiment the selection of airfields, which is limited in particular by the length of the runway, can be advantageously enlarged. Additionally or alternatively, in one embodiment, when the second drive machine fails as a booster, the ducted propeller drive can be driven by the first drive machine alone, and the safety can thus be (further) increased.

In one embodiment of the aircraft, two ducted propeller drives are arranged in particular on the fuselage and / or on the wings of the aircraft. As an alternative to designs, which have a ducted propeller drive arranged centrally on the aircraft, in other designs two ducted propeller drives are arranged, in particular, symmetrically on the fuselage and / or on the wings of the aircraft. A higher propulsion power of the aircraft can be achieved with two ducted propeller drives.

In one embodiment, the aircraft has at least two drive devices which drive the at least one ducted propeller drive and which are arranged in particular in the fuselage of the aircraft. A redundant drive of the at least one ducted propeller drive is thus possible in order to obtain drive power from at least one further drive device if one drive device fails. With the arrangement of the at least two drive devices in the fuselage of the aircraft, in particular with a sound-insulating arrangement of the drive devices, the aircraft can be designed to be low-noise in relation to the surroundings.

In one embodiment, the rotor blades have a blade tip at their radially outer end, the ducted propeller drive being dimensioned, in particular with regard to the radial extension of the rotor blades, such that the blade tips have a circumferential speed during the rotation of the propeller around the drive axis at the essentially constant speed whose Mach number is less than 0.5 and in particular less than 0.45.

The radially outer end of a rotor blade is referred to as the blade tip, even if the radially outer end of the rotor blade is embodied with no or without a substantial radial taper, ie in particular “blunt”. In this embodiment, the ducted propeller drive is dimensioned, in particular with regard to the radial extent of the rotor blades, so that the blade tips have a peripheral speed during the rotation of the propeller around the drive axis, in particular at a substantially constant speed, the Mach number of which is ( Ma ) is less than 0.5 and in particular is less than 0.45. In other words, the ducted propeller drive is dimensioned, in particular with regard to the radial extension of the rotor blades, so that the Mach number Ma , which is the product of the circle number π (Pi = 3.14159) with the diameter D _SSP of the propeller at the blade tips and the nominal value of the, in particular, essentially constant speed n results during the rotation of the propeller calculated circumferential speed, is less than 0.5 and in particular is less than 0.45. This comparatively low peripheral speed at the blade tips leads to a comparatively low level of noise, since the noise generated by a ducted propeller drive increases with increasing peripheral speed at the blade tips. In addition, with lower Mach numbers at the blade tips, the rotor blades are also exposed to lower loads, which in particular also has an advantageous effect on the broadband noise emitted by the ducted propeller drive.

In one embodiment of the aircraft, the ratio of the air pressure in the casing after the guide vanes to the air pressure in the casing in front of the blades during an operating phase of the ducted propeller drive is less than 1.06 and in particular less than 1.04. The low pressure difference applied to the large number of rotor blades when the ducted propeller drive is in operation results in a comparatively low load on the rotor blades compared to conventional propeller and ducted propeller drives, which, in addition to the lower component load, has a particularly advantageous effect on the broadband noise produced.

In one embodiment of the aircraft, the exit speed of the drive jet from the ducted propeller drive is less than 100 meters per second. If the exit speed of the drive jet is low, there is only a small jet noise, which is formed when the thrust jet is mixed with the environment. Low flow and thus exit velocities and a rather low speed of the propeller favor a sound-absorbing design, in particular the implementation of a cut-off design, which enables the attenuation of certain, in particular rather low frequencies of the tonal noise that occurs.

In one embodiment of the aircraft, the number of blades arranged on the hub body of the propeller is in a range from 3 to 22 and in particular in a range from 7 to 16, for example 15. In this embodiment, the propeller has a comparatively high number of blades. This is particularly advantageous in connection with low pressure ratios, such as a ratio of the air pressure in the casing after the guide vanes and in front of the rotor blades of less than 1.06 and in particular less than 1.04 during an operating phase of the ducted propeller drive, as this reduces the aerodynamic load the individual blade can be lowered. In addition, a high number of blades enables a cut-off design, a design by means of which the propagation of the tonal noise component can at least partially be suppressed. The number of guide vanes must be matched to the number of rotor blades in order to prevent or at least reduce the spread of the dominant sound frequencies.

In one embodiment of the aircraft, the number of guide vanes distributed around the inner circumference of the jacket housing is in a range from 3 to 37 and in particular in a range from 26 to 37 or in particular in a range from 3 to 8. The number of guide vanes which are arranged in particular at the same axial height of the casing, is selected in particular in connection with the number of blades on the propeller. A spread of the dominant sound frequencies arising in the ducted propeller drive can be suppressed by means of a suitable ratio of the respective number of rotor blades to guide blades. In particular, it is advantageous if the numbers of blades are relatively prime and are as far apart as possible.

The presently proposed number of guide vanes from 26 to 27 and from 3 to 8, in conjunction with a suitable number of rotor blades, enables different cut-off designs. For example, a combination of 15 rotor blades with 26 guide vanes represents an example of a cut-off design and a combination of 15 rotor blades and 7 guide vanes represents an example of an inverse cut-off design. In connection with low pressure ratios in the ducted propeller drive, in particular A comparatively high number of guide vanes is advantageous, since the aerodynamic load on the guide vanes is also lower, which is associated with further lower noise emissions.

In one embodiment of the aircraft, the diameter of the propeller at the blade tips DSSP is between 600 mm and 1,000 mm, in particular between 750 mm and 900 mm and in particular 850 mm. The enclosure of the propeller in a casing allows thrust to be generated with a comparatively high mass flow, combined with a low jet exit speed and thus low jet noise that is formed when the thrust jet is mixed with the environment. As already stated, low flow and exit speeds in connection with a particularly low speed of the propeller favor a sound-absorbing design, such as a cut-off design. Furthermore, in the case of a design with a diameter of the propeller at the blade tips DSSP between 600 mm and 1,000 mm, only low pressure ratios on the propeller are required for a small increase in speed, which allows operation at low speeds and thus a circumferential machine number of less than 0.5, which allows designs with low noise emissions are possible.

In one embodiment of the aircraft, sound-absorbing devices are arranged on the inner circumference of the jacket housing. Such devices are, in particular, noise reduction measures arranged on the jacket housing, which are matched to the frequency range of the propeller. In particular, noise damping measures in the casing, such as acoustically damping wall elements, in particular acoustic liners, are particularly effective. The noise attenuation of such wall elements becomes more effective if the frequencies to be attenuated are more narrowly limited. The effect of acoustically damping wall elements, which are particularly effective in the area of high-frequency tonal noise, is in particular also promoted by an essentially constant speed of the propeller, in particular interacting with a comparatively high number of blades. Acoustic liners, for example, have good effects with low installation space requirements, especially in the high-frequency range.

In one embodiment of the aircraft, the guide vanes in the jacket housing are arranged inclined to the rear in the direction of the jacket housing downstream. Such an inclination of the guide vanes in the range from 10 ° to 30 ° and in particular from approximately 20 ° in the direction of the jacket housing has proven to be particularly suitable. Such a sweep results, in particular, in a noise reduction because the wake indentations of the rotor blade flow continuously sweep over the guide vanes instead of striking their entire leading edge height at discrete points in time. In addition, a suitable three-dimensional design of the guide vanes, particularly in connection with the sweep, helps reduce the tonal noise via radial interference.

In one embodiment of the aircraft, the blade tips of the rotor blades arranged on the hub body are designed to be laterally inclined to the rear counter to the direction of rotation. Such a lateral inclination of the blade tips, referred to as “lean”, counter to the direction of rotation in the range from 2 ° to 15 ° and in particular in the range from 5 ° to 10 ° has proven to be particularly suitable. A radially concave rotor blade pressure side is thus formed, as a result of which secondary flow losses and the associated noise due to the interaction of rotor blades and blade tip vortices can be reduced.

In one embodiment of the aircraft, the guide vanes are arranged distributed uniformly around the circumference of the casing or are arranged distributed around the circumference of the casing in a predetermined pattern with varying spacings. A variable pitch arrangement of the guide vanes with spacings that vary around the circumference of the casing supports the mitigation of high-frequency components of the tonal noise by dividing the excitation into variable blade passing frequencies. So For example, the distances between the guide vanes can vary by +/- 10%, for example patterns with in particular evenly increasing or decreasing distances or successively increasing and / or decreasing distances are possible. Furthermore, for example, a plurality of groups can be arranged one after the other in the circumferential direction, each with the same or varying distances from one another.

In general, a robust, low-noise design can be created through a suitable choice of 3D design parameters for the elements of the ducted propeller drive and in particular the propeller, the rotor blades and the guide vanes, which has a very stable operating behavior and low noise emissions across all operating states.

In one embodiment, the aircraft has a, in particular maximum, span of at least 5 m, in one embodiment at least 7 m, and / or at most 20 m, in one embodiment at most 16 m. Additionally or alternatively, a maximum take-off weight ("Maximum Take-Off Mass") of the aircraft is at least 650 kg, in one version at least 1000 kg, and / or at most 3000 kg, in one version at most 2000 kg. Additionally or alternatively, in one embodiment, in particular a minimum, maximum or average flight distance of the aircraft is at least 100 km, in one embodiment at least 250 km and / or at most 2000 km, in one embodiment at most 1000 km. Additionally or alternatively, in one embodiment an especially minimum, maximum or average (travel) altitude of the aircraft is at least 750 m, in one embodiment at least 1500 m and / or at most 6000 m, in one embodiment at most 4500 m. In such aircraft, in particular aircraft, which are particularly suitable as air taxis, the present invention can be used with particular advantage because of their operating conditions.

In a second aspect of the invention, a method for operating an aircraft, in particular an aircraft with airfoils, is proposed, which is designed in particular in accordance with one or more of the previously described embodiments of an aircraft. The aircraft has a fuselage for receiving at least one pilot and / or a payload, in particular air freight and / or at least one passenger, and at least one ducted propeller drive, which has a propeller, a hub body and a plurality of uniformly around the outer circumference of the hub body having distributed blades, which are invariably connected to the hub body. The propeller can be rotated about a drive axis and the drive power is supplied to it via a drive shaft arranged essentially radially to the hub body of the propeller. Furthermore, on the drive jet outlet side of the ducted propeller drive, the hub body has an axially displaceable central body with a changing cross-section, in particular tapering on the drive jet outlet side. The ducted propeller drive also has a casing extending coaxially around the drive axis of the propeller, which accommodates the propeller and which, in particular, interacting with the hub body, defines an outlet cross section of the ducted propeller drive on a drive jet outlet side.

In the proposed method, the propeller of the ducted propeller drive is driven at an essentially constant speed in all operating phases of the aircraft. The air mass flow flowing through the ducted propeller drive and thus the thrust of the ducted propeller drive is set during the various operating phases of the drive by adjusting the drive power supplied and / or by adjusting the outlet cross-section of the ducted propeller drive by axially moving the central body.

An aircraft operated with the method is designed according to at least one of the above-described embodiments of an aircraft and can optionally have one or more of the features defined in the preceding description and their modes of operation. With the proposed method, it is possible to operate the aircraft and, in particular, its ducted propeller drive at an operating point that is both acoustically and energetically favorable. Thus, the propeller, in particular the rotor blades and the guide vanes arranged on the circumference of the casing, can be designed acoustically and energetically for the intended speed or the intended speed range in such a way that fuel consumption is minimized and the acoustic cut-off in all essential operating phases of the Aircraft acts.

In one embodiment of the method for operating an aircraft, in a climb phase of the aircraft, the drive power transmitted to the propeller is increased compared to cruising power and the central body is axially displaced on the propeller in order to set an outlet cross-section that is larger than a cruise phase on the drive jet outlet side of the ducted propeller drive, and so on to generate great flight performance required for the climb. This refinement of the method makes it possible to essentially use the aircraft or the ducted propeller drive even in a climbing phase of the aircraft to operate at a constant speed and thus in an operating range provided according to the design of the ducted propeller drive.

In one embodiment of the method for operating an aircraft, in a travel phase of the aircraft, the drive power transmitted to the propeller is reduced to a value that is lower than that of a climb and / or the central body is axially displaced on the propeller by an outlet cross-section that is smaller than in a travel phase of the aircraft Adjust the propulsion jet outlet side of the ducted propeller drive, and thus produce a cruise performance. This embodiment of the method provides the aircraft or the ducted propeller drive with the drive power required according to the intended thrust or the desired cruising speed and the outlet cross section of the ducted propeller drive is adjusted accordingly.

According to one embodiment of the present invention, the aircraft has at least two ducted propeller drives, which are provided for driving or moving the aircraft, in particular in the air, and are referred to here as first and second ducted propeller drives.

According to one embodiment of the present invention, the aircraft has at least one, in particular at least temporarily, rotating second drive machine, which is designed in particular as an electrical machine that is mechanically coupled in one embodiment to the first ducted propeller drive, in particular in terms of drive or force and is correspondingly referred to as the first (rotating) electrical machine, and at least one further, in particular at least temporarily, rotating second drive machine, which is in particular also designed as an electrical machine and with the second ducted propeller drive, in particular in terms of drive or force, is mechanically coupled in one embodiment and is accordingly referred to as a second (rotating) electrical machine.

In one embodiment, the first and / or second rotating electrical machine (each) is arranged completely or partially in the fuselage, in a further development in a rear half of the fuselage (in the longitudinal or flight direction). In this way, in one embodiment, the noise emission of the aircraft can be (further) improved.

Additionally or alternatively, in one embodiment, the first rotating electrical machine with the first ducted propeller drive is via at least one single or multi-stage gear, in one embodiment gear, in particular bevel gear and / or planetary gear, which is correspondingly referred to here as the first gear, and / or at least one, in particular electrical, mechanical and / or hydraulic clutch coupled. Additionally or alternatively, in one embodiment, the second rotating electrical machine with the second ducted propeller drive is via at least one single or multi-stage gear, in one embodiment gear, in particular bevel gear and / or planetary gear, which is correspondingly referred to here as a second gear, and / or at least one, in particular electrical, mechanical and / or hydraulic coupling coupled. In this way, in one embodiment, the noise emission of the aircraft can be (further) improved.

• - in wenigstens einem Betriebszustand die zweite elektrische Maschine mit elektrischer Energie von der ersten elektrischen Maschine und/oder einem ersten Energiespeicher versorgt bzw. hierzu vorgesehen, insbesondere eingerichtet, bzw. wird verwendet, der in wenigstens einem, insbesondere diesem und/oder einem anderen, Betriebszustand die erste elektrische Maschine mit elektrischer Energie versorgt bzw. hierzu vorgesehen, insbesondere eingerichtet, bzw. wird verwendet; und/oder
• - in wenigstens einem Betriebszustand die erste elektrische Maschine mit elektrischer Energie von der zweiten elektrischen Maschine und/oder einem, insbesondere von dem ersten Energiespeicher verschiedenen, in einer Ausführung unabhängigen und/oder beabstandeten, insbesondere räumlich getrennten, zweiten Energiespeicher versorgt bzw. hierzu vorgesehen, insbesondere eingerichtet, bzw. wird verwendet, der in wenigstens einem, insbesondere diesem und/oder einem anderen, Betriebszustand die zweite elektrische Maschine mit elektrischer Energie versorgt bzw. hierzu vorgesehen, insbesondere eingerichtet, bzw. wird verwendet. Entsprechend wird nach einer Ausführung der vorliegenden Erfindung zum Betreiben eines hier beschriebenen Luftfahrzeugs mithilfe dieser Versorgungseinrichtung
• - in wenigstens einem Betriebszustand die zweite elektrische Maschine mit elektrischer Energie von der ersten elektrischen Maschine und/oder dem ersten Energiespeicher;
• - in wenigstens einem Betriebszustand die erste elektrische Maschine mit elektrischer Energie von der zweiten elektrischen Maschine und/ oder dem zweiten Energiespeicher;
• - in wenigstens einem Betriebszustand die erste elektrische Maschine mit elektrischer Energie von dem ersten Energiespeicher und/ oder nicht mit elektrischer Energie von dem zweiten Energiespeicher und/ oder die zweite elektrische Maschine mit elektrischer Energie von dem zweiten Energiespeicher und/ oder nicht mit elektrischer Energie von dem ersten Energiespeicher; und/ oder
• - in wenigstens einem Betriebszustand die erste und zweite elektrische Maschine mit elektrischer Energie von dem ersten und/ oder zweiten Energiespeicher versorgt

bzw. ist das Luftfahrzeug bzw. die Versorgungseinrichtung hierzu vorgesehen, insbesondere eingerichtet, bzw. wird hierzu verwendet.According to one embodiment of the present invention, the aircraft has at least one supply device which

• - In at least one operating state, the second electrical machine is supplied with electrical energy from the first electrical machine and / or a first energy store or provided for this purpose, in particular set up, or used, which in at least one, in particular this and / or another, operating state the first electrical machine is supplied with electrical energy or provided for this purpose, in particular set up, or is used; and or
• - In at least one operating state, the first electrical machine is supplied with electrical energy from the second electrical machine and / or a second energy store, in particular different from the first energy store, independent and / or spaced apart in one embodiment, in particular spatially separated, or provided for this purpose, in particular set up or used, which in at least one, in particular this and / or another, operating state supplies the second electrical machine with electrical energy or is provided, in particular set up, or is used. Accordingly, according to one embodiment of the present invention, this supply device is used to operate an aircraft described here
• - In at least one operating state, the second electrical machine with electrical energy from the first electrical machine and / or the first energy store;
• - In at least one operating state, the first electrical machine with electrical energy from the second electrical machine and / or the second energy store;
• - In at least one operating state, the first electrical machine with electrical energy from the first energy store and / or not with electrical energy from the second energy store and / or the second electrical machine with electrical energy from the second energy store and / or not with electrical energy from the first energy storage; and or
• - In at least one operating state, the first and second electrical machines are supplied with electrical energy from the first and / or second energy store

or the aircraft or the supply device is provided for this purpose, in particular set up, or is used for this purpose.

• - insbesondere bei Beeinträchtigung der Energieversorgung der zweiten elektrischen Maschine durch den (hierzu vorgesehenen) zweiten Energiespeicher kann die zweite elektrische Maschine (auch) durch den ersten Energiespeicher (der ersten elektrischen Maschine) und/oder die erste elektrische Maschine selber, die hierzu in einer Ausführung generatorisch bzw. als Generator betrieben wird bzw. fungiert, versorgt, insbesondere mitversorgt werden, bzw. umgekehrt;
• - insbesondere bei Beeinträchtigung der Energieversorgung der ersten elektrischen Maschine durch den (hierzu vorgesehenen) ersten Energiespeicher kann die erste elektrische Maschine (auch) durch den zweiten Energiespeicher (der zweiten elektrischen Maschine) und/oder die zweite elektrische Maschine selber, die hierzu in einer Ausführung generatorisch bzw. als Generator betrieben wird bzw. fungiert, versorgt, insbesondere mitversorgt werden.

This means that one or more redundancy is provided in one version:

• - In particular if the energy supply of the second electrical machine is impaired by the second energy store (provided for this purpose), the second electrical machine can (also) through the first energy store (the first electrical machine) and / or the first electrical machine itself, which for this purpose in one embodiment operated or functions as a generator or as a generator, supplied, in particular also supplied, or vice versa;
• - In particular if the energy supply of the first electrical machine is impaired by the first energy store (provided for this purpose), the first electrical machine can (also) through the second energy store (the second electrical machine) and / or the second electrical machine itself, which for this purpose in one embodiment is operated or functions as a generator or as a generator, supplied, in particular also supplied.

As a result, in one embodiment, at least two, preferably (mutually) independent, energy sources can be made available and / or electrical power can be exchanged between the drives of the at least two ducted propeller drives and / or, in particular, the safety, in particular in the "one engine inoperative" case, increase.

In one embodiment, in at least one operating state, the first energy store supplies the first electrical machine with electrical energy and the second electrical machine, in particular working or driving the second ducted propeller drive and / or supplied with electrical energy by the second energy store, does not supply electrical energy or is electrically isolated from this, in particular via the power electronics described below, and / or supplied with electrical energy in at least one, in particular this, operating state, the second electrical machine and the, in particular, working or the first The ducted propeller drive and / or the first electrical machine supplied with electrical energy by the first energy store does not have electrical energy or is electrically separated from it, in particular via the power electronics, or the aircraft is provided for this purpose , in particular set up or used for this purpose.

Additionally or alternatively, in one embodiment the aircraft has a first (electrical) power network or a first (electrical) circuit with the first electrical machine and the first energy store, which is used to supply the first electrical machine with electrical energy from the first energy store provided, in particular set up, is or is used, and a different second (electrical) power network or a second electrical circuit with the second electrical machine and the second energy store, which is used to supply the second electrical machine with electrical energy from the second energy store is provided, in particular set up, is or is used, the or the first and second power grid or circuit in one embodiment being redundant or independent of one another in such a way that even when the first electrical circuit or circuit is interrupted, -netzes the second electrical machine ine via the second electrical power network or circuit with electrical energy from the second energy store and / or also when the second electrical circuit or network is interrupted, the first electrical machine via the first electrical power network or circuit can be supplied with electrical energy from the first energy store, in particular is supplied. In one embodiment, the first and second power supply network or first and second power circuit are electrically connected to one another in such a way that, even if the first electrical circuit or network is interrupted, the first electrical machine is connected to the second electrical power supply network or network at at least one point. circle with electrical energy from the second energy store and / or also when the second electrical circuit or network is interrupted at at least one point, the second electrical machine via the first electrical network or circuit can be supplied with electrical energy from the first energy store is, in particular, is supplied. In a further development, the or the first and second electrical power network or circuit are at least partially spaced from one another. Additionally or alternatively, in one embodiment, the first electrical machine, in particular via the first described below Power electronics connected to the first energy store and the second electrical machine, in particular via the second power electronics described below, to the second energy store via separate lines (electrically). As a result, security can be (further) increased in one version.

In one embodiment, the supply device has at least one power electronics unit, in one embodiment one or the first power electronics unit that supplies, in particular, the first electrical machine or is provided, in particular installed or used, and one that supplies, in particular, the second electrical machine or provided for this purpose, in particular set up or used, second power electronics. In a further development, the first and second power electronics are provided redundantly or the first power electronics are also provided for supplying the second electrical machine or the second power electronics are also provided for supplying the first electrical machine, in particular set up or used for this purpose. As a result, in one embodiment, the branching of the electrical energy can be varied simply (more), reliably (more), quickly (more) and / or precisely (r) and / or safety can be (further) increased.

In one embodiment, the aircraft has at least one first drive machine in the form of an internal combustion engine, which is coupled to the first ducted propeller drive, in one embodiment mechanically, in particular via the first transmission and / or (at least) one clutch, and is referred to here as the first internal combustion engine , and / or at least one further first drive machine in the form of an internal combustion engine, which is coupled to the second ducted propeller drive, in one embodiment mechanically, in particular via the second transmission and / or (at least) one clutch, and is referred to here as a second internal combustion engine .

In one embodiment, the aircraft has a hybrid drive concept in which the first internal combustion engine and the first rotating electrical machine drive the first ducted propeller drive, in one embodiment in at least one operating state, or the second internal combustion engine and the second rotating electrical machine drive the second ducted propeller drive , in one embodiment in at least one operating state together.

In one embodiment, the first internal combustion engine drives the first ducted propeller drive and the first rotating one in at least one operating state, in particular for one or for, in particular further or continued, start (s) with a failed first rotating electrical machine and / or during a cruise electrical machine does not switch on the first ducted propeller drive and / or in at least one operating state, in particular in the event of a malfunction of the first internal combustion engine, the first internal combustion engine, which is disengaged for this purpose in one embodiment, does not switch on the first ducted propeller drive and the first rotating electrical machine switches the first ducted propeller drive on and / or in at least one operating state, in particular at or for, in particular regular, start (s), the first internal combustion engine and the first rotating electrical machine jointly on the first ducted propeller drive or the two machines are provided for this purpose, in particular set up or are used for this. Additionally or alternatively, in one embodiment, the second internal combustion engine drives the second ducted propeller drive in at least one operating state, in particular during or for, in particular further or continued, start (s) with a failed second rotating electrical machine and / or during a cruise the second rotating electrical machine does not switch on the second ducted propeller drive and / or in at least one operating state, in particular in the event of a fault in the second internal combustion engine, the second internal combustion engine, which is disengaged for this purpose in one embodiment, does not switch on the second ducted propeller drive and the second rotating electrical machine the second ducted propeller drive on and / or in at least one operating state, in particular on or at, in particular regular, start (s), the second internal combustion engine and the second rotating electrical machine jointly on the second ducted propeller drive or are the two dimensions Machines are provided for this purpose, in particular set up or used for this purpose.

In particular, the first or second rotating electrical machine, respectively, as a booster, can temporarily increase the drive power in the case of increased requirements, in particular when the aircraft is taking off. As a result, in one embodiment, the rate of climb and / or short take-off capability of the aircraft can be increased and, in particular, the use as an air taxi and / or the noise emission of the aircraft can be (further) improved, in particular by quick (re) s removal from the airfield. Additionally or alternatively, in one embodiment the selection of airfields, which is limited in particular by the length of the runways, can be advantageously enlarged. Additionally or alternatively, in one embodiment, when the first and / or second rotating electrical machine fails as a booster, the first and / or second ducted propeller drive can be driven solely by the respective internal combustion engine, thereby increasing safety (further).

In one embodiment, the first internal combustion engine has at least one piston engine and / or at least one gas turbine and / or is arranged entirely or partially in the fuselage. Additionally or alternatively, in one embodiment the second internal combustion engine has at least one piston engine and / or at least one gas turbine and / or is arranged entirely or partially in the fuselage. In one embodiment, this allows the efficiency and / or noise emission of the aircraft to be (further) improved.

In one embodiment, the first and / or second internal combustion engine is (in each case) operated with liquid fuel, in one embodiment its piston engine with gasoline or diesel and / or its gas turbine with kerosene, or is provided for this purpose, in particular set up, in particular So the piston engine is a gasoline or diesel engine. In one embodiment, the first and / or second internal combustion engine (each) is operated with gaseous fuel, in one embodiment its piston engine and / or its gas turbine is operated with methane, hydrogen or the like, or is provided, in particular set up, for this purpose. In one embodiment, this allows the efficiency and / or noise emission of the aircraft to be (further) improved.

In one embodiment, the first and / or second energy store (each) has one or more primary cell (s), in particular battery (s), and / or secondary cell (s), in particular accumulator (s). In one embodiment, the first and / or second energy store (each) has one or more galvanic or fuel cell (s), in particular with hydrogen, methanol, butane, natural gas or other fuels. In one embodiment, this allows the efficiency and / or noise emission of the aircraft to be (further) improved.

Additionally or alternatively, the first and / or second energy storage device (each) has one or more fuel cell (s) and / or additionally or alternatively to a first internal combustion engine coupled to the first ducted propeller drive and / or a second one coupled to the second ducted propeller drive Internal combustion engine, the aircraft has in one embodiment no or at least one additional rotating electrical machine, which is coupled to the first ducted propeller drive, in one embodiment mechanically, in particular via the first gearbox and / or at least one clutch, and / or none or at least one other rotating electrical machine, which is coupled to the second ducted propeller drive, in one embodiment mechanically, in particular via the second gear and / or at least one clutch, this further and / or other rotating electrical machine in one embodiment (each) in at least one Operating condition nd is supplied with electrical energy by one, possibly further, fuel cell or is provided for this purpose, in particular is set up. Thus, in one embodiment, a fuel cell electric machine arrangement can be used instead of the first or second internal combustion engine of the hybrid drive concept described here. In one embodiment, this allows the efficiency and / or noise emission of the aircraft to be (further) improved.

• - ein hybrides Antriebskonzept mit der ersten und/oder zweiten Brennkraftmaschine und der ersten und zweiten elektrischen Maschine, die in einer Weiterbildung als Booster und/oder zur Erhöhung der Sicherheit dienen;
• - eine Abwandlung dieses hybriden Antriebskonzepts mit der weiteren und/oder andere elektrischen Maschine, die die erste bzw. zweite Brennkraftmaschine unterstützen oder ersetzen, und der ersten und zweiten elektrischen Maschine; und
• - ein rein elektrisches Antriebskonzept mit der ersten und zweiten elektrischen Maschine, wobei sowohl bei den beiden anderen Antriebskonzept als auch insbesondere hier Brennstoffzellen als erster bzw. zweiter Energiespeicher besonders vorteilhaft sein können.

Thus, an aircraft according to the present invention can in particular implement or have the following drive concepts:

• - A hybrid drive concept with the first and / or second internal combustion engine and the first and second electrical machine, which in a development serve as a booster and / or to increase safety;
• - A modification of this hybrid drive concept with the further and / or other electrical machine that support or replace the first or second internal combustion engine, and the first and second electrical machine; and
• - A purely electric drive concept with the first and second electric machine, with both the other drive concept and, in particular, fuel cells as the first and second energy storage device being particularly advantageous here.

In one embodiment, an output shaft of the first internal combustion engine or further electrical machine and an output shaft of the second internal combustion engine or other electrical machine are arranged in opposite directions; in particular, one of these output shafts can extend from the respective electrical or internal combustion engine (from (going)) towards the rear of the aircraft or to the rear and the other of the two output shafts extend in opposite directions from the respective electric or internal combustion engine (outgoing) in the direction of the bow or front of the aircraft or forwards. As a result, a compact (re) drive arrangement can be implemented in one embodiment.

In one embodiment, an output shaft of the first internal combustion engine or further electrical machine and an output shaft of the second internal combustion engine or other electrical machine are arranged in the same direction; in particular, these two output shafts can each move from the respective electrical or internal combustion engine (from (outgoing)) towards the rear of the Aircraft or to the rear or in the direction of the bow or front of the aircraft or to the front. As a result, an advantageous (more) load distribution can be implemented in one embodiment.

Additionally or alternatively, in one embodiment, one or the output shaft of the first internal combustion engine or further electrical machine and one or the output shaft of the second internal combustion engine or other electrical machine are offset from one another in the transverse direction or direction of a transverse axis of the aircraft, in one development on opposite sides Arranged sides of a, in particular central, longitudinal or meridian plane of the aircraft.

As a result, a compact (re) drive arrangement and / or advantageous (re) load distribution can be implemented in one embodiment.

Additionally or alternatively, one or the output shaft of the first internal combustion engine or further electrical machine and one or the output shaft of the second internal combustion engine or other electrical machine, in particular an interface of this output shaft with the respective machine and / or one, in particular the first or second, transmission, offset or stepped in relation to one another in the longitudinal direction or in the direction of a longitudinal axis of the aircraft, arranged in a further development on opposite sides of a transverse plane of the aircraft. As a result, a compact (re) drive arrangement and / or advantageous (re) load distribution can be implemented in one embodiment.

Additionally or alternatively, in one embodiment one or the output shaft of the first internal combustion engine or further electrical machine and one or the output shaft of the second internal combustion engine or other electrical machine are arranged on opposite sides of the first transmission. As a result, a compact (more), in particular narrower, drive arrangement can be implemented in one embodiment. In another embodiment, one or the output shaft of the first internal combustion engine or further electrical machine and one or the output shaft of the second internal combustion engine or other electrical machine are arranged on the same side of the first transmission. As a result, an advantageous (more) load distribution can be implemented in one embodiment.

Additionally or alternatively, in one embodiment, one or the output shaft of the first internal combustion engine or further electrical machine and one or the output shaft of the second internal combustion engine or other electrical machine are arranged on opposite sides of the second transmission. As a result, a compact (more), in particular narrower, drive arrangement can be implemented in one embodiment. In another embodiment, one or the output shaft of the first internal combustion engine or further electrical machine and one or the output shaft of the second internal combustion engine or other electrical machine are arranged on the same side of the second transmission. As a result, an advantageous (more) load distribution can be implemented in one embodiment.

Additionally or alternatively, in one embodiment, an output shaft of the first internal combustion engine or further electrical machine and an output shaft of the second internal combustion engine or other electrical machine form an angle with one another of at most 45 °, in particular at most 30 °, in one embodiment at most 15 ° and in particular 0 ° is, so the two output shafts are in one embodiment, at least substantially, parallel to one another. As a result, a compact (re) drive arrangement and / or advantageous (re) load distribution can be implemented in one embodiment.

In one embodiment, the first and / or second internal combustion engine (each) has an engine supercharger, in particular one or more exhaust gas turbochargers. In one embodiment, this allows the efficiency and / or noise emission of the aircraft to be (further) improved.

Additionally or alternatively, in one embodiment, the first and / or second internal combustion engine (each) has at least one single-channel or multi-channel exhaust line. In a further development, the or one or more of the exhaust pipe (s) each has one or more silencers. In this way, in one embodiment, the noise emission of the aircraft can be (further) improved.

Additionally or alternatively, in one embodiment the or one or more of the exhaust line (s) each has an exhaust gas cleaning device, in particular one or more exhaust gas catalytic converter (s) and / or particle filter (s). As a result, in one embodiment, the pollutant emissions of the aircraft can be reduced and the aircraft can thus be used in the vicinity of localities and / or at low (more) n cruising altitudes.

In one embodiment, an output shaft of the first electrical machine and an output shaft of the second electrical machine are arranged in opposite directions; in particular, one of these output shafts can extend from the respective electrical machine (from (going)) in the direction of the tail of the aircraft or to the rear and the other of the Both output shafts extend in opposite directions from the respective electrical machine (out (going)) in the direction of the bow or front of the aircraft or forwards. As a result, a compact (re) drive arrangement can be implemented in one embodiment.

In another embodiment, an output shaft of the first electrical machine and an output shaft of the second electrical machine are arranged in the same direction; in particular, these two output shafts can each extend from the respective electrical machine (from (outgoing)) towards the tail of the aircraft or towards the rear or in Extend towards the bow or front of the aircraft or forward. As a result, an advantageous (more) load distribution can be implemented in one embodiment.

Additionally or alternatively, in one embodiment, one or the output shaft of the first electrical machine and one or the output shaft of the second electrical machine are offset from one another in the transverse direction or direction of a transverse axis of the aircraft, in a further development on opposite sides of a, in particular central, Arranged longitudinal plane of the aircraft. As a result, a compact (re) drive arrangement and / or advantageous (re) load distribution can be implemented in one embodiment.

Additionally or alternatively, one or the output shaft of the first electrical machine and one or the output shaft of the second electrical machine, in particular an interface of this output shaft with the respective machine and / or a transmission, are in the longitudinal direction or direction of a longitudinal axis of the Aircraft offset from one another or stepped, in a development arranged on opposite sides of a transverse plane of the aircraft. As a result, a compact (re) drive arrangement and / or advantageous (re) load distribution can be implemented in one embodiment.

Additionally or alternatively, one or the output shaft of the first electrical machine and one or the output shaft of the second electrical machine are arranged on opposite sides of the first transmission in one embodiment. As a result, a compact (more), in particular narrower, drive arrangement can be implemented in one embodiment. In another embodiment, one or the output shaft of the first electrical machine and one or the output shaft of the second electrical machine are arranged on the same side of the first transmission. As a result, an advantageous (more) load distribution can be implemented in one embodiment.
Additionally or alternatively, in one embodiment, one or the output shaft of the first electrical machine and one or the output shaft of the second electrical machine are arranged on opposite sides of the second transmission. As a result, a compact (more), in particular narrower, drive arrangement can be implemented in one embodiment. In another embodiment, one or the output shaft of the first electrical machine and one or the output shaft of the second electrical machine are arranged on the same side of the second transmission. As a result, an advantageous (more) load distribution can be implemented in one embodiment.

Additionally or alternatively, in one embodiment, one or the output shaft of the first electrical machine and one or the output shaft of the second electrical machine form an angle with one another of at most 45 °, in particular at most 30 °, in one embodiment at most 15 ° and in particular 0 ° is, so the two output shafts are in one embodiment, at least substantially, parallel to one another. As a result, a compact (re) drive arrangement and / or advantageous (re) load distribution can be implemented in one embodiment.

As already mentioned, in one embodiment the aircraft is an aircraft with, in particular fixed (stationary) wings. In one embodiment, the aircraft or aircraft has at least one, in particular fixed (standing) e, front wing and at least one, in particular fixed (standing) e, rear wing, which are offset from one another in the direction of a vertical axis and in the direction of a longitudinal axis of the aircraft and are connected by at least one, in particular inclined or inclined, lateral strut. In a further development, the aircraft or aircraft has at least two, in particular fixed (standing) e, front wings, which are arranged on opposite sides of the fuselage, and at least two, in particular fixed (standing) e, rear wings, which are on opposite sides Sides of the fuselage are arranged on, wherein the front and rear wing arranged on one side of the fuselage are offset from one another in the direction of a vertical axis and in the direction of a longitudinal axis of the aircraft and are connected by at least one, in particular inclined or inclined, lateral strut. In one embodiment, the aircraft has what is known as a box wing configuration. In one embodiment, this allows the efficiency and / or noise emission of the aircraft to be (further) improved.

In one embodiment, the aircraft has one or more air passage (s) through which the first electrical machine and / or the second electrical machine and / or the first internal combustion engine and / or the second internal combustion engine and / or the further electrical machine and / or the other electrical machine is cooled in at least one operating state or which is / are or is / will be used for this purpose, in particular designed, at least one first air passage for cooling the first electrical machine and / or first internal combustion engine and / or further electrical machine and / or at least one second air passage for cooling the second electrical machine and / or second internal combustion engine and / or other electrical machine.

In one embodiment, the or one or more of the air passage (s) each has one or more cooling air supply (s), in particular fresh air supply (s), in one embodiment one or more opening (s) in the fuselage, and at least one or more, in one embodiment in the direction of a longitudinal axis of the aircraft against the or one or more of the cooling air supply (s) offset, cooling air discharge (s), in particular one or more opening (s) in the fuselage. In one embodiment, this allows the efficiency of the aircraft to be (further) improved. In particular in the case of electrical or internal combustion engines which are arranged at least partially in the fuselage and by means of which the noise emission can be reduced in one embodiment, such cooling can particularly advantageously improve the efficiency of the aircraft.

Additionally or alternatively, in one embodiment, the aircraft has one or more heat exchangers through which the first electrical machine and / or the second electrical machine and / or the first internal combustion engine and / or the second internal combustion engine and / or the further electrical machine and / or the other electrical machine is cooled in at least one operating state or which is / are or is / are provided for this purpose, in particular set up, is / are or is / are used, in one embodiment one or more first heat exchangers for cooling the first electrical machine and / or first internal combustion engine and / or further electrical machine and / or one or more second heat exchangers for cooling the second electrical machine and / or second internal combustion engine and / or other electrical machine. In one embodiment, this allows the efficiency of the aircraft to be (further) improved. In particular in the case of electrical or internal combustion engines which are arranged at least partially in the fuselage and by means of which the noise emission can be reduced in one embodiment, such cooling can particularly advantageously improve the efficiency of the aircraft.

• - einem Innenraum des Rumpfes zur Aufnahme des wenigstens einen Piloten und/ oder der Nutzlast einerseits und
• - der ersten elektrischen Maschine und/oder zweiten elektrischen Maschine und/oder ersten Brennkraftmaschine und/oder zweiten Brennkraftmaschine und/oder weiteren und/oder anderen elektrischen Maschine andererseits

wenigstens ein Brandschott angeordnet. Hierdurch kann in einer Ausführung eine thermische Belastung des Innenraums vom Maschinenraum bzw. dessen Wärmeentwicklung reduziert, vorzugsweise vermieden, und/oder die Sicherheit erhöht werden.In one implementation is between

• - An interior of the fuselage for receiving the at least one pilot and / or the payload on the one hand and
• the first electrical machine and / or second electrical machine and / or first internal combustion engine and / or second internal combustion engine and / or further and / or other electrical machine on the other hand

at least one firewall arranged. As a result, in one embodiment, a thermal load on the interior of the machine room or its heat generation can be reduced, preferably avoided, and / or safety can be increased.

• - der ersten elektrischen Maschine und/oder ersten Brennkraftmaschine und/oder weiteren elektrischen Maschine einerseits und
• - der zweiten elektrischen Maschine und/oder zweiten Brennkraftmaschine und/oder anderen elektrischen Maschine andererseits wenigstens ein, in einer Ausführung ein- oder mehrfach abgewinkeltes, Brandschott angeordnet. Hierdurch kann/ können in einer Ausführung bei Feuer in einem dieser beiden durch dieses Brandschott getrennten Räume die Maschine(n) in dem anderen dieser beiden Räume den Flugbetrieb aufrechterhalten.

Additionally or alternatively, in one version there is between

• - The first electrical machine and / or first internal combustion engine and / or further electrical machine on the one hand and
• - The second electrical machine and / or second internal combustion engine and / or other electrical machine on the other hand at least one, in one embodiment, one or more angled, firewall arranged. As a result, in an embodiment in the event of a fire in one of these two rooms separated by this fire partition, the machine (s) in the other of these two rooms can maintain flight operations.

Additionally or alternatively, in one embodiment the first and second energy stores are separated from one another, in a further development a fire bulkhead is arranged between the first and second energy store, in one embodiment one of the above-mentioned fire bulkheads. As a result, in one embodiment in the event of a fire in one of these two rooms separated by this fire partition, the or one or more of the machine (s) can be supplied by the energy storage device in the other of these two rooms and thus maintain flight operations in one embodiment.

In one embodiment, the first and second ducted propeller drive are arranged on opposite sides of the fuselage, in a further development on or to the side of the fuselage (es), in particular (each) on a pylon connected to the fuselage and / or on a rear half of the fuselage. In one embodiment, the fuselage is arranged between the two ducted propeller drives.

Additionally or alternatively, the first and second ducted propeller drive are arranged in one embodiment behind and / or above the front wing (s) and / or in front of and / or below the rear wing (s). Additionally or alternatively, in one embodiment the front wings are swept back and / or the rear wing (s) are swept forward.

As a result, in one embodiment, in particular in combination of two or more of these features, the flight characteristics of the aircraft can be improved, in particular in combination with the load distribution through the electric and / or internal combustion engines arranged at least partially in the fuselage.

Additionally or alternatively, in one embodiment the first ducted propeller drive is connected to the first electric machine and / or to the first internal combustion engine and / or to the further electric machine, in an embodiment with the (first) gearbox via which it is coupled to the first ducted propeller drive or are, via at least one drive shaft common in one embodiment, which forms an angle with an axis of rotation of the first ducted propeller drive and / or an output shaft (at least one) of this machine (s) of at least 45 °, in particular at least 60 °, in one embodiment is at least 75 ° and in particular 90 °, (mechanically) coupled. In one embodiment, the first ducted propeller drive is (mechanically) coupled to this drive shaft via at least one (further) single or multi-stage gear, in one embodiment gear, in particular bevel gear and / or planetary gear.

Additionally or alternatively, in one embodiment the second ducted propeller drive is connected to the second electrical machine and / or to the second internal combustion engine and / or to the other electrical machine, in an embodiment with the (second) gearbox via which it is coupled to the second ducted propeller drive or are, via at least one drive shaft common in one embodiment, which forms an angle with an axis of rotation of the second ducted propeller drive and / or an output shaft (at least one) of this machine (s) of at least 45 °, in particular at least 60 °, in one embodiment is at least 75 ° and in particular 90 °, (mechanically) coupled. In one embodiment, the second ducted propeller drive is coupled (mechanically) to this drive shaft via at least one (further) single or multi-stage gear, in one embodiment gear, in particular bevel and / or planetary gear. In this way, in one embodiment, a compact (more) drive arrangement can be implemented and / or the corresponding machine (s) can advantageously be arranged at least partially in the fuselage.

In one embodiment, the first rotating electrical machine and the first internal combustion engine or further rotating electrical machine are arranged on opposite sides of the first transmission, in one embodiment they are coupled to one another via the first transmission. As a result, an advantageous (more) load distribution can be implemented in one embodiment. In another embodiment, the first rotating electrical machine and the first internal combustion engine or further rotating electrical machine are arranged on the same side of the first transmission, in one embodiment in series with one another. As a result, a shorter and / or simpler drive arrangement can be implemented in one embodiment.

In one embodiment, the second rotating electrical machine and the second internal combustion engine or other rotating electrical machine are arranged on opposite sides of the second transmission, in one embodiment they are coupled to one another via the second transmission. As a result, an advantageous (more) load distribution can be implemented in one embodiment. In another embodiment, the second rotating electrical machine and the second internal combustion engine or other rotating electrical machine are arranged on the same side of the second transmission, in one embodiment in series with one another. As a result, a shorter and / or simpler drive arrangement can be implemented in one embodiment.

In one embodiment, one or more, in particular all, steps of the method are carried out completely or partially in an automated manner, in particular by the supply device. One or more of the operating states mentioned here are (in each case) flight operating states in which the aircraft is in the air and / or at least one ducted propeller drive generates propulsion.

In the present case, a rotating electrical machine is understood in particular in the customary manner as an electrical machine that converts electrical and mechanical power into one another in at least one (active) operating state or is provided for this purpose, in particular is set up or used, and a (rotating in this operating state ) Has output or drive shaft.

In one embodiment, the aircraft has a (first) drive control which, in at least one operating state, controls the drive of the first ducted propeller drive, in particular the operation of the first electrical machine, the first internal combustion engine and / or the further electrical machine, or which is provided, in particular set up for this purpose , is or is used, and / or a (second) drive control which, in at least one, in particular this or another, operating state, drives the second ducted propeller drive, in particular the operation of the second electrical machine, the second internal combustion engine and / or the other electrical machine, regulates or provided for this purpose, in particular set up, is or is used on. In a further development, these two drive controls are redundant each other or regulate the drive of the first and / or second ducted propeller drive, in particular the operation of the first and / or second electrical machine, the first and / or second internal combustion engine and / or the further and / or other electrical machine, in particular if the other drive control fails , or are provided for this purpose, in particular set up, or are used for this purpose. The first and / or second drive control can be designed, for example, as part of a control or supply device, integrated into such a device and / or operatively connected to such a device, in particular designed to interact with it.

An (improved, in particular reduced) noise emission mentioned here can include, in particular, an (improved, in particular reduced) noise emission in or into the outer field of the aircraft. Additionally or alternatively, an (improved, in particular reduced) noise emission mentioned here can in one embodiment include, in particular be, an (improved, in particular reduced) noise emission in or into the interior (s) of the aircraft.

In one embodiment, the first energy store can provide a power reserve in the event of an impairment, in particular a failure of the second internal combustion engine or other rotating electrical machine (the second rotating electrical machine) or, conversely, the second energy store in the event of an impairment, in particular a failure of the first internal combustion engine or further rotating electrical machine (the first rotating electrical machine) provide a power reserve or be provided for this purpose, in particular set up or used.

In one embodiment, one or more, in particular all, steps of the method are carried out completely or partially in an automated manner, in particular by the controller or its means. The invention allows numerous possibilities for reducing noise from aircraft, based on the higher number of rotor blades that can be realized with it. This reduces the noise emissions, which are particularly relevant in the area close to settlements, and also reduces the structural complexity of the aircraft drive.

• 1 ein Luftfahrzeug nach einer Ausführung der vorliegenden Erfindung in verschiedenen Ansichten;
• 2 eine schematische Schnittdarstellung eines Ausschnitt einer beispielhaften Ausführung eines erfindungsgemäßen Luftfahrzeugs mit einem Mantelpropellerantrieb; und
• 3 eine schematische Darstellung eines beispielhaften Ablaufs des Verfahrens der vorliegenden Erfindung;
• 4 eine schematische Darstellung einer beispielhaften erfindungsgemäßen Schaufelanordnung in einem Mantelpropellerantrieb; und
• 5 eine schematische Schnittdarstellung eines beispielhaften erfindungsgemäßen Luftfahrzeugs.

Further features, advantages and possible applications of the invention emerge from the following description in connection with the figures. Show it

• 1 an aircraft according to an embodiment of the present invention in different views;
• 2 a schematic sectional view of a detail of an exemplary embodiment of an aircraft according to the invention with a ducted propeller drive; and
• 3 a schematic representation of an exemplary sequence of the method of the present invention;
• 4th a schematic representation of an exemplary blade arrangement according to the invention in a ducted propeller drive; and
• 5 a schematic sectional view of an exemplary aircraft according to the invention.

1 shows an aircraft 1 according to an embodiment of the present invention in a frontal view from the front ( 1 (a) ), a side view ( 1 (b) ), a top view from above ( 1 (c) ) and a perspective view obliquely from the front above ( 1 (d) ).

It has a hull 10 to accommodate a pilot and four passengers, as well as two front wings 11 and two aft wings 12th . As in particular in 1 (a) , (b) and (d) are the aft wings 12th against the front wings 11 in the direction of a vertical axis of the aircraft 1 offset. As also particularly in 1 (b) , (c) and (d) are the aft wings 12th against the front wings 11 in the direction of a longitudinal axis of the aircraft 1 offset. The two wings on the same side of the fuselage 11 are each through an inclined side strut 13th connected. On opposite sides of the hull 10 is each a ducted propeller drive 14th arranged.

2 shows a schematic sectional illustration of a detail of an exemplary embodiment of an aircraft according to the invention 1 , Airplane with wings 11 , 12th and with a trunk 10 for receiving at least one pilot and / or one payload, in particular air freight and / or at least one passenger and with at least one ducted propeller drive 14th which on a fuselage 10 of an aircraft 1 is arranged. The hull 10 and the aircraft 1 are only indicated in part.

The ducted propeller drive 14th has a propeller 20th on, the one hub body 21st and a plurality of uniformly around the outer periphery of the hub body 21st distributed blades 22nd has which are invariable with the hub body 21st are connected. The propeller 20th is over a drive axle A. rotatable. Via a radial to the hub body 21st of the propeller 20th arranged drive shaft 5128 is this drive power from a in the fuselage 10 of the aircraft 1 arranged drive device 50 fed. To convert the supplied drive power into rotational energy of the propeller 20th is in the illustrated version in the hub body 21st of the propeller 20th a gear 27 to transfer the drive power from the drive shaft 51 on the propeller 20th arranged. The gearbox is also used 27 in the embodiment shown, also for reducing a drive speed of the drive device 50 . In one embodiment, two drive devices 50 in the fuselage of the aircraft 1 be arranged.

The ducted propeller drive 14th also has a coaxial about the drive axis A. of the propeller 20th extending jacket housing 36 on which the propeller 20th receives and which together with the hub body 21st an outlet cross section 15th the ducted propeller drive 14th on a drive jet outlet side 16 Are defined. The hub body 21st points to the drive jet outlet side 16 the ducted propeller drive 14th a central body axially displaceable along the arrow shown 24 with a tapering cross-section, so that by an axial displacement of the central body 24 the outlet cross-section 15th the ducted propeller drive 14th is adjustable. In 1 is also an alternative design of the central body with dashed lines 24 indicated with changing cross-section.

For axial displacement of the central body 24 is in the illustrated version in the hub body 21st of the propeller 20th a displacement device 26th arranged. Around the inner circumference 34 of the shell 36 is a large number of evenly distributed guide vanes 35 arranged, which firmly with the shell housing 36 are connected and at an axial distance a from the blades 22nd of the propeller 20th are arranged. The inner surfaces of the jacket housing 36 are fluidic and acoustically dependent, in particular, on the speed of the ducted propeller drive 14th cheap designed.

The drive device 50 has at least two drive machines that can be operated in parallel to drive a ducted propeller drive 51 and 52 on, with a first drive machine, designed as an internal combustion engine in the exemplary embodiment 51 is set up for this, the ducted propeller drive 14th to operate in a first operating range, the power requirement of which goes beyond the cruising power, the power of the first prime mover 51 up to twice the performance of a cruise performance. The second drive machine designed as an electrical machine in the exemplary embodiment 52 is set up to drive the ducted propeller 14th parallel to the first drive machine 51 to operate in a second operating area, the performance requirement of which exceeds twice the performance of a cruise performance.

In 3 is an exemplary sequence of the method according to the invention for operating an aircraft 1 , in particular an aircraft with wings 11 , 12th , with a fuselage 10 for receiving at least one pilot and / or one payload, in particular air freight and / or at least one passenger and with at least one ducted propeller drive 14th shown. The method can, for example, be used to operate an aircraft 1 be carried out as exemplified in the 1 and 2 is shown and described.

In the process, the propeller 20th the ducted propeller drive 14th in a first step a ) in all phases of operation of the aircraft 1 driven at a substantially constant speed. Adjusting the flight performance of the ducted propeller drive 14th takes place during the various operating phases by adapting the drive power supplied and / or by reducing the outlet cross-section 15th the ducted propeller drive 14th by axial displacement of the central body 24 is set.

In a second, optional step b), the aircraft is in a climb phase 1 those on the propeller 20th transmitted drive power increased and the central body 24 axially displaced on the propeller by a larger outlet cross-section 15th on the drive jet outlet side 16 the ducted propeller drive 14th set, and so to generate a climb performance required for a climb. In a third, also optional, step c ), which can take place, for example, when the cruising altitude is reached, is in a travel phase of the aircraft 1 those on the propeller 20th transmitted drive power is reduced to a lower drive power compared to a climbing phase and / or the central body 24 axially on the propeller 20th shifted and in particular a smaller outlet cross-section 15th on the drive jet outlet side 16 the ducted propeller drive 14th set to produce a cruise performance.

4th shows a schematic representation of an exemplary blade arrangement according to the invention in a ducted propeller drive 14th in two views. The ducted propeller drive 14th is according to the in 2 shown ducted propeller drive 14th executed and the same elements as shown in 4th have the same reference numbers as in 2 designated. The illustration above shows a front view of a schematic representation of a ducted propeller drive 14th , whereby in the schematic representation only the propeller 20th with hub body 21st and blades 22nd inside the jacket housing 36 is shown. On the representation of the guide vanes 35 behind the blades 22nd have been omitted for reasons of clarity. The arrow shows the direction of rotation U of the propeller 20th and thus the blades 22nd around the drive axis A. at. The one at the radial diameter DSSP of the propeller 20th arranged blade tips 23 of the rotor blades 22nd are opposite to the direction of rotation U at an angle α laterally inclined backwards. In the example in 4th are the blades in the "Lean" design 22nd at an angle α inclined from 10 ° backwards.

The lower representation shows a full section through the longitudinal axis of the exemplary ducted propeller drive 14th similar to 2 . In this illustration, too, the same elements have the same reference symbols as in FIG 2 designated. In contrast to the representation in 2 are shown in 4th only two guide vanes 35 drawn, which in the jacket housing 36 towards the jacket housing 36 at an angle β are arranged inclined downstream to the rear. In the example in 4th are the guide vanes 35 in the design called "arrow" at an angle β from 15 ° downstream in the direction of the shell 36 or the inner circumference 34 of the jacket housing 36 arranged inclined backwards. The one through the ducted propeller drive 14th Air flow is indicated by the three arrows in the direction of flow in front of the casing 36 shown.

5 shows a section through a rear part of the aircraft 1 with the trunk 10 and with two jacketed ducted propeller drives 14A and 14B. In the trunk 10 is a (front) interior 100 of the fuselage to accommodate the pilot and passengers from an engine room through a (first) firewall 101 severed. The engine room is in turn through a (second) fire bulkhead 102 divided along a central longitudinal plane of the aircraft.

In one part of the engine room (right in 5 ) are a first rotating electrical machine 37 and a first internal combustion engine 31 arranged on opposite sides of a first gear 41 and with this via one output shaft each 211 or. 311 connected. The first gear 41 is in turn via a drive shaft 411 with a gear 141 connected, which in turn is connected to the first ducted propeller drive 14A. Between the first electric machine 37 and first transmission 41 and / or between the first internal combustion engine 31 and first gear 41 and / or between first gear 41 and the gear 141 A clutch (not shown) can (each) be provided in order to selectively interrupt the flow of torque via the corresponding shaft. In this way are the first rotating electrical machine 37 and the first internal combustion engine 31 coupled via the first gear 41 to the first ducted propeller drive 14A. In an analogous manner, in the other part of the machine room (left in 5 ) a second rotating electrical machine 38 and a second internal combustion engine 32 arranged on opposite sides of a second gear 42 and with this via a respective output shaft 212 or. 312 connected. The second gear 42 is in turn via a drive shaft 412 with a gear 142 connected, which in turn is connected to the second ducted propeller drive 14B. Between the second electric machine 38 and second transmission 42 and / or between the second internal combustion engine 32 and second gear 42 and / or between second gear 42 and the gear 142 A clutch (not shown) can (each) be provided in order to selectively interrupt the flow of torque via the corresponding shaft. In this way are the second rotating electrical machine 38 and the second internal combustion engine 32 coupled via the second gear 42 to the second ducted propeller drive 14B.

A first air passage for cooling the first electrical machine 37 and first internal combustion engine 31 has a fresh air supply in the form of an opening 111 in the trunk 10 and one in the longitudinal direction or one direction of a longitudinal axis of the aircraft (vertical in 5 ) offset cooling air discharge in the form of an opening 112 in the trunk 10 on. In an analogous manner, a second air passage has for cooling the second electrical machine 38 and second internal combustion engine 32 a fresh air supply in the form of an opening 121 in the trunk 10 and a cooling air discharge offset in the direction of a longitudinal axis of the aircraft in the form of an opening 122 in the trunk 10 on.

An exhaust pipe of the first internal combustion engine 31 has a silencer 321 on, an exhaust pipe of the second internal combustion engine 32 a muffler 322 . There are heat exchangers in each of the two engine room parts 5 arranged for cooling the respective electrical or internal combustion engine. Drive controls 2 , 2 ' regulate the operation of the internal combustion engines 31 , 32 and electrical machines 37 , 38 in particular in the manner explained below.

The internal combustion engines 31 , 32 are made of tanks 200 supplied with fuel and drive the two ducted propeller drives 14A, 14B in a travel or normal (flight) operating mode. In a starting phase, the two electrical ones increase machinery 37 , 38 the drive power and thus enable advantageous high rates of climb and take-offs on short runways at local airports. For this purpose, the first electrical machine 37 via a first circuit or a first power network S1 from a first energy store in the form of a (first) battery 221 and the second electric machine 38 via a second circuit or a second power network S2 from a second energy store in the form of a (second) battery 222 supplied with electrical energy. If the first battery fails 221 supply power electronics 61 , 62 the first electric machine 37 with electrical energy from the second battery 222 . Conversely, the power electronics supply 61 , 62 the second electric machine 38 if the second battery fails 222 with electrical energy from the first battery 221 .

Additionally or alternatively, especially in the event of a failure of the second internal combustion engine 32 , the first internal combustion engine 31 the first electric machine 37 operate as a generator, with the power electronics 61 , 62 (then) from the first electric machine 37 electrical energy output by the first battery 221 , second battery 222 and / or the second electrical machine 38 forward. The same can also be done, especially in the event of a failure of the first internal combustion engine 31 , the second internal combustion engine 32 the second electric machine 38 operate as a generator, with the power electronics 61 , 62 (then) from the second electrical machine 38 electrical energy output by the first battery 221 , second battery 222 and / or the first electrical machine 37 forward.

In this way, the internal combustion engines 31 , 32 be operated more efficiently, in particular in optimal operating ranges, and / or dimensioned smaller. Additionally or alternatively, the risk of a crash in the event of failure of one of the machines and / or energy stores, in particular in the “one engine inoperative” case, can be greatly reduced and electrical power can be exchanged between the drives for this purpose. Additionally or alternatively, the energy stores 221 , 222 be operated more efficiently, in particular in optimal operating ranges, and / or dimensioned smaller.

List of reference symbols

1

Aircraft

2; 2`

Drive control

5

Heat exchanger

10

hull

11

front wings

12

rear wings

13th

side strut

14th

Ducted propeller drive

15th

Outlet cross-section

16

Drive jet outlet side

20th

propeller

21st

Hub body

22nd

Blades

24

Central body

26th

Sliding device

27

transmission

28

drive shaft

31

first internal combustion engine

32

second internal combustion engine

34

inner circumference of the jacket housing

35

Guide vanes

36

Shell housing

37

first rotating electrical machine

38

second rotating electrical machine

50

Drive device

51

first prime mover

52

second prime mover

53

Control device

61

Power electronics

62

Power electronics

100

inner space

101

Firewall

102

Firewall

111

Air inlet

112

Air inlet

121

Air outlet

122

Air outlet

141

transmission

142

transmission

200

tank

211

drive shaft

212

drive shaft

221

first battery (first energy storage)

222

second battery (second energy storage)

311

drive shaft

312

drive shaft

321

silencer

322

silencer

411

drive shaft

412

drive shaft

A.

Drive axle

a

axial distance between rotor blades and guide vanes

c

Speed of sound

D _SSP

Diameter of the propeller at the blade tips

Ma

Mach number

n

Speed of the propeller

S1, S2

Power grid / circuit

U

Direction of rotation

α

Inclination angle of the blades

β

Angle of inclination of the guide vanes

Claims (25)

Aircraft, in particular aircraft with wings (11, 12), with a fuselage (10) for receiving at least one pilot and / or one payload, in particular air freight and / or at least one passenger, and with at least one ducted propeller drive (14), which has: a propeller (20) which has a hub body (21) and a multiplicity of rotor blades (22) evenly distributed around the outer circumference of the hub body (21), which blades are invariably connected to the hub body (21), the propeller (20) is rotatable about a drive axis (A) and is supplied with drive power via a drive shaft (28) arranged essentially radially to the hub body (21) of the propeller (20); and - a casing (36) which extends coaxially around the drive axis (A) of the propeller (20) and which accommodates the propeller (20) and which, in particular interacting with the hub body (21), has an outlet cross-section (15) of the casing propeller drive (14) defined on a drive jet outlet side (16); characterized in that the hub body (21) on the drive jet outlet side (16) of the ducted propeller drive (14) has an axially displaceable central body (24) with a changing cross section, in particular tapering on the drive jet outlet side (16), whereby an axial displacement of the central body (24) the outlet cross-section (15) of the ducted propeller drive (14) is adjustable. Aircraft according to at least one of the preceding claims, characterized in that a displacement device (26) for axially displacing the central body (24) is arranged in the hub body (21) of the propeller (20). Aircraft according to at least one of the preceding claims, characterized in that the outlet cross section (15) on the drive jet outlet side (16) of the ducted propeller drive (14) is caused by an axial displacement of the central body (24) in relation to a position with a maximum opening in a range from 0% to 50%, in particular in a range from 0% to 30% and in particular in a range from 0% to 20%. Aircraft according to at least one of the preceding claims, characterized in that the casing (36) accommodates a plurality of guide vanes (35) distributed around the inner circumference of the casing (36). Aircraft according to at least one of the preceding claims, characterized in that the propeller (20) and in particular the geometry of the blades (22) and / or the guide vanes (52) and / or the casing (36) is set up for this over the entire operating range of the ducted propeller drive (14) to be operated at a substantially constant speed, which is in a range from 1,500 to 5,000 rpm, in particular in the range from 2,000 to 4,000 rpm and in particular at around 2,600 rpm. Aircraft according to at least one of the preceding claims, characterized in that in the fuselage (10) and / or in at least one wing (11, 12) of the aircraft (1) at least one drive device (50) providing drive power to the ducted propeller drive (14), in particular is arranged soundproofed. Aircraft according to at least one of the preceding claims, characterized in that a gear (27) for transmitting the drive power from the drive shaft (28) to the propeller (20) is arranged in particular in the hub body (21) of the propeller (21), which in particular also serves to step up or step down a drive speed of the drive device (50). Aircraft according to at least one of the preceding claims, characterized in that the drive device (50) of the ducted propeller drive (14) has a control device (53) and is set up by adapting the output drive power and cooperating with an axially displaceable central body to keep the speed of the propeller (20) of the ducted propeller drive (14) essentially constant regardless of the respective power requirement during a flight, in particular for the benefit of lower noise emissions. Aircraft according to at least one of the preceding claims, characterized in that the drive device (50) has at least two drive machines (51, 52) which can be operated in parallel to drive a ducted propeller drive (14). Aircraft after Claim 9 , characterized in that a first drive machine (51) is set up to operate the ducted propeller drive (14) in a first operating range, the power requirement of which goes beyond the cruise performance, with the power of the first drive machine (51) increasing up to 1.5 times, in particular up to 1.8 times and in particular up to twice the performance of a cruise performance. Aircraft according to one of the Claims 9 or 10 , characterized in that the second drive machine (52) is set up to operate the ducted propeller drive (14) parallel to the first drive machine (51) in a second operating range, the power requirement of which is more than 1.5 times, in particular more than 1.8 -fold and in particular more than twice the performance of a cruise performance. Aircraft after Claim 11 , characterized in that the first drive machine (51) can be operated through the parallel operation with the second drive machine (52) in particular independently of the power requirement in the second operating range in a map area with favorable energy consumption and / or lower noise emissions and / or in which the power output the first prime mover (51) is increased. Aircraft according to at least one of the Claims 9 to 12th , characterized in that the first drive machine (51) is an internal combustion engine and the second drive machine (52) is an electrical machine. Aircraft according to at least one of the preceding claims, characterized by at least two ducted propeller drives (14) which are arranged in particular on the fuselage (10) and / or on at least one wing (11, 12) of the aircraft (1). Aircraft according to at least one of the Claims 6 to 14th , characterized by at least two drive devices (50) which drive the at least one ducted propeller drive (14) and which are arranged in particular in the fuselage (10) of the aircraft (1). Aircraft according to at least one of the preceding claims, characterized in that the rotor blades (22) have a blade tip (23) at their radially outer end and the ducted propeller drive (14) is dimensioned, in particular with regard to the radial extension of the rotor blades (22), such that the Blade tips (23) during the rotation of the propeller (20) about the drive axis (A) at an essentially constant speed (n) have a peripheral speed whose Mach number (Ma) is less than 0.5 and in particular less than 0.45 . Aircraft according to at least one of the preceding claims, characterized in that the ratio of the air pressure in the casing (36) after the guide vanes (35) and the air pressure in the casing (36) before the blades (22) is less during an operating phase of the ducted propeller drive (14) is than 1.06 and in particular less than 1.04 and / or the exit speed of the drive jet from the ducted propeller drive (14) is less than 100 meters per second. Aircraft according to at least one of the preceding claims, characterized in that the number of rotor blades (22) arranged on the hub body (21) of the propeller (20) is in a range from 3 to 22 and in particular in a range from 7 to 16 and / or the number of guide vanes (22) distributed around the inner circumference (34) of the casing (36) is in a range from 3 to 37 and in particular in a range from 26 to 37 or in particular in a range from 3 to 8. Aircraft according to at least one of the preceding claims, characterized in that the diameter (D _SSP ) of the propeller (20) at the blade tips (23) is between 600 mm and 1,000 mm, in particular between 750 mm and 900 mm and in particular 850 mm. Aircraft according to at least one of the preceding claims, characterized in that the guide vanes (35) in the jacket housing (36) are arranged inclined to the rear at an angle (β) downstream in the direction of the jacket housing (36) and / or the blade tips (23) of the on the hub body (21) arranged rotor blades (22) against the direction of rotation (U) at an angle (α) laterally inclined backwards. Aircraft according to at least one of the preceding claims, characterized in that - it has a span of at least 5 m, in particular at least 7 m, and / or at most 20 m, in particular at most 16 m; and / or - its maximum take-off weight is at least 650 kg, in particular at least 1000 kg, and / or at most 3000 kg, in particular at most 2000 kg. Method for operating an aircraft (1), in particular an aircraft with wings (11, 12), in particular according to at least one of the preceding claims, with a fuselage (10) for receiving at least one pilot and / or one payload, in particular air freight and / or at least of a passenger and with at least one ducted propeller drive (14) which has: - A propeller (20) which has a hub body (21) and a multiplicity of rotor blades (22) which are uniformly distributed around the outer circumference of the hub body (21) and are invariably connected to the hub body (21), the propeller (20 ) is rotatable about a drive axis (A) and this drive power is supplied via a drive shaft (28) arranged essentially radially to the hub body (21) of the propeller (20), the hub body (21) on the drive jet outlet side (16) of the ducted propeller drive ( 14) has an axially displaceable central body (24) with a changing cross-section, in particular tapering on the drive jet outlet side (16); and - A casing (14) which extends coaxially around the drive axis (A) of the propeller (20) and which accommodates the propeller (20) and which in particular interacts with the hub body (21) at an outlet cross section (15) of the casing propeller drive (14) a drive jet outlet side (16) defined; characterized in that the propeller (20) of the ducted propeller drive (14) is driven at a substantially constant speed in all operating phases of the aircraft (1), the thrust of the ducted propeller drive (14) during the various operating phases by adjusting the drive power supplied and / or by adjusting the outlet cross section (15) of the ducted propeller drive (14) by axially displacing the central body (24). Method for operating an aircraft according to Claim 22 , characterized in that in a climb phase of the aircraft (1) the drive power transmitted to the propeller (20) is increased compared to a cruise power and the central body (24) is axially displaced on the propeller (20) by an outlet cross-section ( 15) on the drive jet outlet side (16) of the ducted propeller drive (14), and thus to generate the climb performance required for a climb. Method for operating an aircraft according to at least one of Claims 22 or 23 , characterized in that in a travel phase of the aircraft (1) the drive power transmitted to the propeller (20) is reduced to a lower value compared to a climbing phase and / or the central body (24) is axially displaced on the propeller (20) by one compared to a travel phase of the aircraft (1) to set a smaller outlet cross-section (15) on the drive jet outlet side (16) of the ducted propeller drive (14), and thus to generate cruising performance. Method for operating an aircraft, in particular according to one of the preceding claims, characterized in that with the aid of the supply device (61, 62) - in at least one operating state, the second electrical machine (38) receives electrical energy from the first electrical machine (37) and / or the first energy store (221); - In at least one operating state, the first electrical machine (37) with electrical energy from the second electrical machine (38) and / or the second energy store (222); and / or - in at least one operating state, the first electrical machine (37) is supplied with electrical energy from the first energy store (221) and / or the second electrical machine (38) is supplied with electrical energy from the second energy store (222).

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