System comprising a carrier aircraft and a satellite aircraft

Abstract

The invention relates to a system comprising a carrier aircraft (1) and a satellite aircraft (2), wherein the carrier aircraft and the satellite aircraft can be detachably connected to each other by means of a coupling device (3, 4, 5), wherein the carrier aircraft has a drive device (6) and is designed to carry the satellite aircraft during take-off from the Earth's surface, and wherein the satellite aircraft has a solar drive device (7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, 9a, 9b, 9c) and a hydrogen drive device (10, 11, 12, 15, 9a, 9b, 9c, 9d, 9e), each of which can be electrically connected to at least one electric drive motor (8).

Description

[0001] APUS ZERO EMISSION GMBH

[0002] 247PCT 2991

[0003] System with a carrier aircraft and a satellite aircraft

[0004] The invention lies in the field of aeronautical engineering, mechanics and electrical engineering and is particularly advantageous for applications where a satellite aircraft is to move at high altitude for a longer period of time with reasonable effort.

[0005] For some time now, there have been efforts to create aircraft that can move with the least possible energy expenditure. In many cases, these are aircraft used with a relatively light payload for observation, measurement, or communication purposes. One particular possibility is that such aircraft operate at high altitudes in low air pressure, which, however, also necessitates that all systems be suitable for such high-altitude flights.

[0006] A well-known problem is that the energy required to bring an energy-efficient aircraft to cruising altitude is initially quite high. In this context, combined shuttle systems have already been developed, in which an aircraft is transported to altitude by a carrier aircraft or a launch vehicle and then released from the carrier vehicle.

[0007] In light of the prior art, the present invention aims to create a system and a satellite aircraft that enable the longest possible and most reliable operation of the satellite aircraft with a limited payload at flight altitude with the least possible effort.

[0008] The problem is solved using the features of the independent patent claims. The dependent patent claims present possible implementations of the solution.

[0009] The invention thus relates to a system comprising a carrier aircraft and a satellite aircraft,

[0010] wherein the carrier aircraft and the satellite aircraft can be detachably connected to each other by means of a coupling device and wherein the carrier aircraft has a propulsion system and is equipped to carry the satellite aircraft during a launch from the Earth's surface,

[0011] wherein the satellite aircraft has a solar propulsion system and a hydrogen propulsion system, each of which can be electrically connected to at least one propulsion electric motor.

[0012] The hydrogen propulsion system can include a hydrogen tank and a fuel cell unit capable of providing sufficient electrical power to operate the propulsion motor. The hydrogen tank can be for storing gaseous hydrogen or liquid hydrogen. The electric propulsion motor can also be powerful enough to enable the satellite aircraft to fly continuously at high altitudes. The solar propulsion system incorporates photovoltaic cells capable of providing sufficient power to operate the satellite aircraft with the electric propulsion motor at high altitudes. In some cases, the solar propulsion system may be somewhat smaller, requiring continuous operation only through combined and / or simultaneous use of both the solar and hydrogen propulsion systems.This design makes it possible to transport a payload exceeding that of a purely solar-powered aircraft. Due to hydrogen's high energy content, the satellite aircraft can still carry and transport enough hydrogen to remain at high altitudes for extended periods.

[0013] The solar drive system and a hydrogen drive system can each be connected to a separate drive electric motor, or both can be connected to the same motor or motors. In particular, in the case of combined and alternating operation of the solar drive system and the hydrogen drive system, the solar drive system can be operated during the times when sunlight is available, and the times when no sunlight is available can be bridged with the hydrogen drive system.

[0014] In some cases, it may also be provided that the satellite aircraft contains a small electrochemical battery that can store excess energy generated by the solar propulsion system.

[0015] The carrier aircraft can have a conventional internal combustion engine, but it can also have an electric propulsion system, either alternatively or additionally. The electric propulsion system can be powered, for example, by a fuel cell system connected to a hydrogen tank. Such a design of the carrier aircraft with a hydrogen-based propulsion system offers logistical advantages, as both aircraft—the carrier aircraft and the satellite aircraft—can be refueled with hydrogen. Furthermore, the carrier aircraft's hydrogen tank can also be used to refuel the satellite aircraft in flight.For this purpose, a detachable mechanical coupling device may be provided, designed to mechanically couple the carrier aircraft and the satellite aircraft, and which may also include a latching device to allow coupling between the two aircraft, for example for refueling, even in flight. The satellite aircraft may have a device for carrying a payload, for example within a wing or in a fuselage section that is an extension of a fuselage section designed as a hydrogen tank. This allows the payload to be accommodated without increasing the wind resistance of the satellite aircraft.

[0016] Another possibility is to arrange the payload in one or more engine nacelles without having to significantly modify the aircraft's external contour.

[0017] A special design of the system may provide that the satellite aircraft has a fuselage which is formed, at least in one longitudinal section, by a first hydrogen tank.

[0018] With this type of design, weight can be saved by having the hydrogen tank fulfill additional mechanical functions of the fuselage besides storing hydrogen. Furthermore, in many cases, the hydrogen tank is not enclosed by an additional bulkhead, thus reducing the fuselage cross-section. For the construction of the hydrogen tank, it is usually designed to be sufficiently robust, especially if it is a gas tank, to easily or with minimal modifications fulfill the function of an aircraft fuselage. In some cases, the advantage can also be achieved that the small amounts of hydrogen gas escaping from the tank can dissipate immediately and do not accumulate in a fuselage enclosing the hydrogen tank.

[0019] Such a design of the satellite aircraft can be applied to single-fuselage aircraft as well as to aircraft with multiple fuselages, so that several fuselages can be formed entirely or at least partially by a hydrogen tank each.

[0020] For the aforementioned embodiment, one or more hydrogen tanks can, for example, consist at least partially of a fiber-reinforced plastic. The fiber orientation can be selected to meet the stability requirements for the pressure of the tank contents. For example, in a cylindrical hydrogen tank, at least some reinforcing fibers can be oriented circumferentially or at least transversely to the cylinder axis. Furthermore, special fiber reinforcements and / or some fibers oriented longitudinally / along the cylinder axis can achieve a particular flexural stiffness that is advantageous for its use as a hull section.

[0021] Another embodiment of the system may provide that the satellite aircraft has two or more fuselages arranged side by side with their longitudinal axes parallel to each other, each of which is formed by a hydrogen tank in at least one longitudinal section.

[0022] Such an aircraft can, for example, have one or two engine nacelles with electric motors in the forward section, whereby the single engine nacelle can be connected to the two hydrogen tanks, or each of the two engine nacelles can be connected to one hydrogen tank. The system can also be configured so that the first hydrogen tank and / or the second hydrogen tank of the satellite aircraft carries a tail assembly. The first and second hydrogen tanks can be positioned parallel to each other and each form at least one longitudinal section of a fuselage.

[0023] Such a control structure can be, for example, a vertical or horizontal stabilizer, or a combined vertical and horizontal stabilizer.

[0024] Another embodiment of the system may provide that the first hydrogen tank and / or the second hydrogen tank of the satellite aircraft is / are load-bearingly connected to a wing.

[0025] The wing(s) and one or more hydrogen tanks can be directly connected. Each wing can also be connected to an engine nacelle, which in turn is structurally connected to a hydrogen tank designed as a fuselage or fuselage section. One or more hydrogen tanks can also extend partially into the wing or be mechanically and / or fluidically connected (via fluid lines) to one or more additional hydrogen tanks located within the wing. This allows for the storage of a large amount of hydrogen in the aircraft with minimal space requirements and makes it easily available for a fuel cell system.

[0026] For example, it may also be provided that the satellite aircraft has a rechargeable electrical energy storage system.

[0027] It may be provided that the electrical energy storage device can be charged by an electrical charging current that can be generated by photovoltaic cells of the solar drive device and / or a fuel cell of the hydrogen drive device.

[0028] Thus, the energy storage system can, for example, store excess solar energy from the solar propulsion system or energy from the fuel cell system for operation without sunlight or for a flight phase in which there is an increased power demand.

[0029] Furthermore, the first and / or second hydrogen tank of the satellite aircraft may be designed to have higher tensile strength on a side subjected to particularly high stress from external forces during operation, in particular through a greater wall thickness or a greater number or a selected orientation of reinforcing fibers, than in the other areas. Such reinforcement may be provided in the lower and / or upper region of the hydrogen tank or in one or both side regions.

[0030] Another embodiment of the system may provide that the first and second hydrogen tanks of the satellite aircraft are located essentially forward or aft of the wing in the direction of flight. Furthermore, the satellite aircraft may be provided with additional hydrogen tanks on the side of the wing opposite the first and / or second hydrogen tank in the direction of flight.

[0031] Furthermore, it may be provided that the first and / or second hydrogen tank of the satellite aircraft is connected to the other hydrogen tanks by hydrogen lines, in particular a trim system is provided which is designed to control the filling of the hydrogen tanks in such a way as to limit or avoid a shift in the center of gravity of the satellite aircraft.

[0032] Another embodiment of the system may provide that the satellite aircraft has photovoltaic cells on the wings and / or on at least one surface of a hydrogen tank.

[0033] This design allows the surface of the satellite aircraft to be optimally utilized for photovoltaic energy generation. Photovoltaic cells can, for example, also be incorporated into / integrated into the wall of the hydrogen tank.

[0034] It may also be provided that the carrier aircraft has an electric propulsion system with at least one hydrogen tank, one fuel cell and one propulsion electric motor.

[0035] This propulsion system of the carrier aircraft can be provided as an alternative to, or in addition to, a conventional combustion engine. In a further embodiment, both the carrier aircraft and the satellite aircraft can each have one or more propellers, with the satellite aircraft in particular having one or more propellers optimized for operation at a higher altitude than at least one propeller of the carrier aircraft.

[0036] The satellite aircraft is designed for the most energy-efficient operation / flight at high altitudes, for example, above 6,000 m or above 10,000 m. This means, for instance, that the wingspan of the satellite aircraft may be larger than that of the carrier aircraft, which is designed for short transport flights. Furthermore, the propellers, or parts thereof, of the satellite aircraft may differ in design from those of the carrier aircraft. For example, the satellite aircraft's propellers may have a larger diameter than the carrier aircraft's propeller(s). Additionally, the pitch of the propellers of the carrier aircraft and the satellite aircraft, and / or the number and profile of the propeller blades, may also differ.

[0037] Ultimately, it may also be provided that the satellite aircraft has at least two powered propellers optimized for operation at different altitudes, with at least one of the propellers being provided for propulsion during the launch of the carrier aircraft and the satellite aircraft to assist the propulsion of the carrier aircraft.

[0038] The invention relates not only to a system of the type described above, but also to an aircraft, in particular a satellite aircraft for such a system, comprising at least one fuselage and a hydrogen propulsion system, which includes at least one hydrogen tank and one fuel cell and which is electrically connectable to at least one drive electric motor, wherein at least one fuselage is formed by a hydrogen tank in at least one longitudinal section. Such an aircraft can have any one or a combination of features mentioned above in connection with the satellite aircraft of the described system, such as the combination with a solar propulsion system, the distribution of photovoltaic cells, or hydrogen tanks in or on the aircraft. The invention is illustrated below with reference to exemplary embodiments in the figures of a drawing and subsequently explained.

[0039] This shows

[0040] Figure 1: a side view of a carrier aircraft with a satellite aircraft attached to it,

[0041] Figure 2: a view of a satellite aircraft with a fuselage from above,

[0042] Figure 3: a top view of a twin-fuselage satellite aircraft,

[0043] Figure 4: A front view of a carrier aircraft with a satellite aircraft attached to it, as well as

[0044] Figure 5: a top view of a carrier aircraft with a satellite aircraft attached to it.

[0045] Figure 1 shows a side view of a satellite aircraft 2 mounted on the top of a carrier aircraft 1. The direction of flight is indicated in each figure by an arrow labeled 19. The satellite aircraft is mechanically connected to the carrier aircraft at docking points 3, 4, and 5, with only docking points 3 and 5 shown in Figure 1. Figure 5, described below, shows a top view of all three docking points 3, 4, and 5. The carrier aircraft 1 can be shorter, more compact, and heavier than the satellite aircraft and, most importantly, is equipped with a more powerful propulsion system.The carrier aircraft can have a conventional internal combustion engine or a turboprop engine, but it can also have a hydrogen propulsion system with a fuel cell and / or an electrochemical energy storage device in the form of a battery and an electric motor driving a propeller. Each of these propulsion units can be present multiple times on the carrier aircraft. As shown in Figure 1, it can also be advantageous for the coupling of the two aircraft if the carrier aircraft has at least one propeller drive directly on its fuselage, particularly at the rear. The carrier aircraft has landing gear that is sufficiently robust to allow takeoff and landing of both coupled aircraft. In many cases, the satellite aircraft has no landing gear or only minimal landing gear that allows for landing.

[0046] In the embodiment created, the carrier aircraft, due to its specialization for lower flight altitudes, also has a smaller wingspan than the satellite aircraft.

[0047] The satellite aircraft has one or more electric propulsion devices, namely, in the example shown in Figures 1, 4 and 5, four electric motors that drive the propellers 9b, 9c, 9d, 9e.

[0048] Propellers 9b and 9c may differ from propellers 9d and 9e, and the engines driving propellers 9b and 9c may differ from those driving propellers 9d and 9e. However, the propellers of each propeller pair (9b, 9c and 9d, 9e) may be identical in design and driven by the same engines. One of the engine and propeller pairs may be optimized for takeoff and low-altitude flight to assist the carrier aircraft's propulsion during takeoff, while the other pair is optimized for energy-efficient high-altitude propulsion, for example, above 10,000 meters. For instance, the propeller diameter of the higher-altitude pair may be larger than the diameter of the lower-altitude pair. Furthermore, the propeller geometry, particularly the airfoil profile, may also differ.

[0049] The drives for propellers 9b, 9c each have drive electric motors that are powered by one or more of the following sources: solar cells, electrochemical battery, fuel cell.

[0050] One of the propulsion pairs 9b, 9c and 9d, 9e can be powered by a different source or combination of sources than the other propulsion pair. For example, a propulsion system or such a propulsion pair optimized for higher altitudes can be powered by a fuel cell and solar cells, and in particular additionally by a battery, while a propulsion system optimized for lower altitudes is powered exclusively or predominantly by a fuel cell and in particular additionally by a battery charged before takeoff.

[0051] In this propulsion system optimized for higher altitudes, the fuel cell(s), solar cells, and, in particular, the battery will, in some cases, supply energy intermittently, but not necessarily continuously. Instead, they can operate according to a schedule that takes into account the periods when solar energy is available. During these periods, such a propulsion system can, in many cases, be powered exclusively by the generated solar energy, or only a small portion will be contributed by a fuel cell.

[0052] In any case, the described combination of different electrical energy sources makes it possible to transport significantly larger payloads than would be possible with an exclusively solar-powered drive.

[0053] The invention also relates to a single satellite aircraft with the described propulsion combinations operating independently without a carrier aircraft. In such a case, the satellite aircraft can, for example, be transported aloft inside a larger aircraft and released from there, or launched into the air by a ground-based propulsion system. Such an aircraft can be configured as shown in Figures 2 and 3.

[0054] Figure 2 shows an example of a satellite aircraft that has a single fuselage 13.

[0055] The fuselage has a nacelle 13a at its forward end, which contains a drive electric motor 8 that drives a propeller 9a. A fuel cell 15 and a battery 18 are also located in the nacelle 13a and are electrically connected to the motor. Additionally, solar cells / photovoltaic cells 7a and 7b on the wings, photovoltaic cells 7c on the fuselage 10, and photovoltaic cells 7e on the tail assembly are shown symbolically and are electrically connected to the drive electric motor. The photovoltaic cells can occupy a larger area on these components than depicted in the drawing. For example, the majority (>50%) of the upper surface of the wings and fuselage can be covered with photovoltaic cells.

[0056] The fuselage 10 of the satellite aircraft can be designed entirely or at least partially as a hydrogen tank and can have a round or elliptical cross-section, with the diameter of the fuselage / tank being variable along its length. In the example shown, the longitudinal section of the fuselage 13 between the nacelle 13a and the rear end of the aircraft is designed as a hydrogen tank. The tank can also extend into the nacelle 13a. It can be divided longitudinally into several gas-tight compartments or at least compartments separated from each other by fire-resistant walls.

[0057] The tank can be made entirely or partially of a metal, such as stainless steel, or of a fiber-reinforced plastic, with the reinforcing fibers being, for example, carbon fibers. Some of the carbon fibers can be oriented circumferentially or spirally around the tank to primarily absorb the forces generated by the internal pressure. Other fibers can be oriented primarily longitudinally along the tank to absorb the bending forces caused by the weight of the aircraft. The wings 24, 25 can be directly connected to the tank 10 in a load-bearing manner. However, they can also be connected to the nacelle 13a, which in turn is connected to the tank 10. Additional hydrogen tanks can be arranged in the wings 24, 25. Alternatively, or in addition, further hydrogen tanks can also be arranged in the nacelle 13a.The hydrogen tanks can be fluidically interconnected to compensate for the weight distribution between different parts of the aircraft during hydrogen consumption in flight. For this purpose, the various tanks can be connected by means of fluid lines and controllable valves. Figure 3 shows, by way of example, the connecting line 20 between the two tanks 11 and 12, each forming a fuselage.

[0058] Figure 3 shows a satellite aircraft with two fuselages 11, 12, each of which is configured as a hydrogen tank. The hydrogen tanks 10, 11, 12 of Figures 2 and 3 can each have round or elliptical cross-sections, with the diameter of the fuselage varying along its length. The longitudinal section of the fuselage 13, 14 between the nacelle 13a, 14a and the rear of the aircraft or the tail assembly can also be configured as a hydrogen tank. The tanks can also extend into the nacelles 13a, 14a. Each tank can be longitudinally subdivided into several gas-tight compartments and / or compartments separated from each other by firewalls.

[0059] Each tank can be made entirely or partially of a metal, such as stainless steel, or of a fiber-reinforced plastic, and / or of layers of various materials. The tanks can each be designed so that they are surrounded by only a single wall, which, however, can be multi-layered. The tank wall can be designed without cavities and its outer surface can form the outer skin of the aircraft fuselage.

[0060] In the aircraft shown in Figure 3, photovoltaic cells 7f, 7g, 7h are shown as examples on the so-called inner wing between the nacelles 13a, 14a, as well as on one of the tanks 11 and on the trailing tail. Additional hydrogen tanks can be distributed in the same way as in the aircraft shown in Figure 2, as can further photovoltaic cells, for example, on both hydrogen tanks 11, 12 and on the entire wings. The aircraft shown in Figure 3 can have a propulsion system in each of the nacelles 13a, 14a, designed in the same way as the propulsion system described with reference to Figure 2. This also includes a corresponding combination of electrical energy sources for the propulsion electric motors consisting of fuel cells, solar cells, and one or more batteries.

[0061] Figures 2 and 3 also show possible payload arrangement regions, labeled 30 and 31 respectively in the gondola, and 26 and 27 respectively in the airfoil / inner wing. These locations are, however, only examples.

[0062] Figure 4 shows the system with a carrier aircraft 1 and a satellite aircraft 2, which is also shown in Figure 1, in a front view. It is clear that the wingspan 17 of the satellite aircraft is significantly larger than the wingspan of the carrier aircraft 1, which is a fuselage-wing aircraft. The landing gear 28 of the carrier aircraft 1 is shown below it.

[0063] Figure 5 shows a top view of the system. The distribution of the propulsion systems, energy sources, photovoltaic cells, and hydrogen tanks can be configured in the satellite aircraft shown in Figure 5 in the same way as in the embodiment shown in Figure 3. In Figure 5, the propulsion system of the carrier aircraft 1 is shown in the form of a drive electric motor 23, which is arranged at the rear of the fuselage. The electric drive motor is connected to a fuel cell 22, which is supplied from a hydrogen tank 21. In addition to a hydrogen tank 21 in the fuselage itself, the carrier aircraft can, of course, also have hydrogen tanks in the wings and / or at least one electrochemical battery in the fuselage. This propulsion system of the carrier aircraft can also be designed, for example, as a conventional internal combustion engine, such as a piston engine or a turboprop engine.

[0064] The described system enables the operation of a satellite aircraft at high altitude for extended periods without the need for external energy supplies, such as hydrogen. Furthermore, this system allows for the transport of a payload exceeding that of purely solar-powered satellite aircraft.

Claims

APUS ZERO EMISSION GMBH 247PCT 2991 Patent claims 1. System comprising a carrier aircraft (1) and a satellite aircraft (2), wherein the carrier aircraft and the satellite aircraft are detachably connectable to each other by means of a coupling device (3, 4, 5) and wherein the carrier aircraft has a propulsion system (6) and is configured to carry the satellite aircraft during a launch from the Earth's surface, characterized in that the satellite aircraft has a solar propulsion system (7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, 9a, 9b, 9c) and a hydrogen propulsion system (10, 11, 12, 15, 9a, 9b, 9c, 9d, 9e), each of which is electrically connectable to at least one propulsion electric motor (8).

2. System according to claim 1, characterized in that the satellite aircraft (2) has a fuselage (13) which is formed at least in a longitudinal section by a first hydrogen tank (10, 11, 12).

3. System according to claim 2, characterized in that the satellite aircraft (2) has two or more fuselages (13, 14) arranged side by side with their longitudinal axes parallel to each other, each of which is formed at least in one longitudinal section by a hydrogen tank (11, 12).

4. System according to claim 2 or 3, characterized in that the first hydrogen tank (11) and / or the second hydrogen tank (12) of the satellite aircraft (2) carries a tail assembly (16).

5. System according to one of claims 2 to 4, characterized in that the first hydrogen tank (11) and / or the second hydrogen tank (12) of the satellite aircraft (2) is / are load-bearingly connected to a wing (17).

6. System according to one of claims 2 to 5, characterized in that the satellite aircraft (2) has a rechargeable electrical energy storage device (18).

7. System according to claim 6, characterized in that the electrical energy storage device (18) can be charged by an electrical charging current which can be generated by photovoltaic cells (7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h) of the solar propulsion device (7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, 9a, 9b, 9c, 9d, 9e) and / or a fuel cell (15) of the hydrogen propulsion device (10, 11, 12, 15, 9a, 9b, 9c).

8. System according to one of claims 2 to 7, characterized in that the first and / or the second hydrogen tank (11, 12) of the satellite aircraft (2) has a higher tensile strength on a side that is particularly stressed by external forces during operation, in particular by a greater wall thickness or a greater number or a selected orientation of reinforcing fibers, than in the other areas.

9. System according to one of claims 2 to 8, characterized in that the first and second hydrogen tanks (11, 12) of the satellite aircraft (2) are arranged substantially in front of or behind the wing (17) in the direction of flight (19) and that the satellite aircraft has further hydrogen tanks on the side of the wing opposite the first and / or second hydrogen tank in the direction of flight.

10. System according to claim 9, characterized in that the first and / or second hydrogen tank (11, 12) of the satellite aircraft (2) is connected to each other and / or to the further hydrogen tanks by hydrogen lines (20), wherein in particular a trim system is provided which is configured to control the filling of the hydrogen tanks in such a way as to limit or avoid a shift in the center of gravity of the satellite aircraft.

11. System according to one of claims 2 to 10, characterized in that the satellite aircraft (2) has photovoltaic cells (7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h) on the wings of the airfoil and / or on at least one surface of a hydrogen tank.

12. System according to one of claims 1 to 11, characterized in that the carrier aircraft (1) has an electric drive with at least one hydrogen tank (21), a fuel cell (22) and a drive electric motor (23).

13. System according to any one of claims 1 to 12, characterized in that both the carrier aircraft (1) and the satellite aircraft (2) each have one or more propellers (6, 9a, 9b, 9c, 9d, 9e), wherein in particular the satellite aircraft has one or more propellers (9a, 9b, 9c, 9d, 9e) that are optimized for operation at a higher altitude than at least one propeller (6) of the carrier aircraft.

14. System according to one of claims 1 to 13, characterized in that the satellite aircraft (2) has at least two driveable propellers (9a, 9b, 9c, 9d, 9e) optimized for operation at different altitudes, wherein in particular at least one of the propellers is provided for propulsion during the launch of the carrier aircraft (1) and the satellite aircraft to assist the propulsion of the carrier aircraft.

15. Aircraft, in particular satellite aircraft (2) for a system according to one of claims 1 to 14, with at least one fuselage (13, 14) and a hydrogen propulsion system (10, 11, 12, 15, 9a, 9b, 9c, 9d, 9e) comprising at least one hydrogen tank and a fuel cell and electrically connectable to at least one propulsion electric motor (8), characterized in that at least one fuselage is formed at least in a longitudinal section by a hydrogen tank (10, 11, 12).

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