Flying object

Abstract

In order to specify a flying object (1, 101, 201, 301, 401) with a center of gravity, a fuselage (10), a pressure chamber (4) arranged in the fuselage (10), a propulsion system (3) operable with a cryogenic fuel (LH2) and at least one cryogenic tank (11, 13) connected to the fuselage (10) for storing the cryogenic fuel (LH2), which can be operated efficiently and stably, it is proposed that the cryogenic tank (11, 13) be arranged outside the pressure chamber (4).

Description

[0001] The present invention relates to a flying object comprising a center of gravity, a fuselage, a pressure chamber arranged in the fuselage, a propulsion system operable with a cryogenic fuel and at least one cryotank connected to the fuselage for storing the cryogenic fuel.

[0002] Examples of propulsion systems that can be operated with a cryogenic fuel include gas turbines, fuel cells, and electric motors.

[0003] Hydrogen has been considered as a potential fuel in the past due to its high energy density. To compensate for the disadvantage of its very low volumetric density, the first hydrogen propulsion systems integrated into aircraft were cryogenic. Examples include a B-57 converted by NASA, but more modern designs such as the Tupolev Tu-155, which the Soviet Union introduced in the 1990s, or the Cryoplane from 2000, are examples of aircraft of the type mentioned above.

[0004] Against the backdrop of the endeavor to make aviation as environmentally friendly as possible, the further development of aircraft of the aforementioned type has once again come into sharper focus. Various configurations and approaches to tank integration have been proposed. For example, EP 4124568A1 discloses an aircraft with a hydrogen tank located in the rear of the aircraft.

[0005] The fundamental drawback of such a fuel tank arrangement is that the aircraft's center of gravity increases towards the tail. With a large proportion of fuel mass, this can lead to stability problems or difficulties in integrating the landing gear or designing the empennage. Therefore, in the aircraft previously disclosed in EP 4124568A1, an additional passenger deck was positioned forward of the center of gravity.

[0006] Another known approach is to install an additional cryogenic tank in the forward part of the fuselage, within the pressurized cabin. However, if the cockpit is to be accessible from the cabin, this approach is problematic because the forward cryogenic tank must have a smaller diameter than the pressurized cabin. Additionally, for safety reasons, this arrangement requires a lower operating pressure to prevent hydrogen from entering the cabin and forming an ignitable mixture in the event of a leak. This leads to premature venting and thus to a further adverse operational limitation. This, in turn, reduces the gravimetric efficiency of the tank. The gravimetric efficiency of a tank is the ratio of the mass of fuel the tank can hold to the sum of that fuel mass and the mass of the empty tank.Ideally, the gravimetric efficiency reaches a value of 1. This is the case when the aircraft structure can simultaneously function as the tank wall, so that no additional weight is added by the tanks. This is the case, for example, when fuel is stored in the wings. Against this background, the present invention aims to provide a means of lifting an aircraft of the type mentioned above, which can be operated efficiently and stably.

[0007] According to the invention, the problem in an aircraft of the type mentioned above is solved by arranging the cryogenic tank outside the pressurized compartment. This measure makes it possible, according to the invention, to design the shape of the cryogenic tank independently of the shape of the pressurized compartment and thus optimize it with regard to gravimetric efficiency. For example, a favorable tank shape can be used that utilizes the entire fuselage cross-section. This maximizes the gravimetric efficiency of the tank. By arranging the cryogenic tank outside the pressurized compartment, it does not restrict the pressurized compartment. This is advantageous, for example, in manned aircraft that therefore have a cockpit which must be accessible within the pressurized cabin. Furthermore, multiple cryogenic tanks can be arranged in such a way that the flight stability is not impaired by the cryogenic tanks.Furthermore, arranging the cryogenic tank outside the pressure chamber advantageously allows for a higher operating pressure in the tank compared to tanks operated in the printed area.

[0008] In particular, in a preferred embodiment of the invention, the cryogenic fuel contains liquid hydrogen (LH2).

[0009] In order to achieve a more flexible design of the aircraft according to the invention with regard to efficiency, redundancy and flight stability, several cryotanks are provided according to a favorable embodiment of the invention.

[0010] In a further advantageous embodiment of the aircraft according to the invention, if the multiple cryogenic tanks are arranged in a distributed manner, the position of the aircraft's center of gravity can be specifically influenced by the suitable placement and dimensioning of the individual cryogenic tanks. In particular, a minimal shift in the center of gravity can be achieved by a suitable distributed arrangement of the cryogenic tanks, regardless of the payload. Furthermore, in a further advantageous embodiment, the position of the center of gravity can be adjusted by selectively pumping the fuel between the tanks during flight. In this case, the aircraft has suitable pumps and lines.

[0011] In particular, an advantageous embodiment of the invention provides that the cryogenic tanks are arranged over the aircraft in such a way that their torques neutralize each other with respect to the center of gravity. Depending on the arrangement of the cryogenic tanks within the scope of the invention, both torques about the longitudinal axis and torques about the transverse axis can be neutralized. This advantageously ensures that the aircraft remains stable even when using the cryogenic tanks. Furthermore, it advantageously allows for a minimization of the center of gravity area across all loading conditions.

[0012] In a preferred embodiment of the aircraft according to the invention, a cranial cryogenic tank arranged forward of the center of gravity and a caudal cryogenic tank arranged aft of the center of gravity are provided. The cranial cryogenic tank is able to counteract the torque exerted by the caudal cryogenic tank located in the tail region. Ideally, it is even possible to neutralize the pitching moment and thus the trim drag if the two cryogenic tanks are appropriately dimensioned. For this purpose, fuel can also be pumped between the caudal and cranial tanks within the scope of the invention.

[0013] Because both the cranial and caudal cryogenic tanks are arranged outside the pressurized compartment according to this embodiment of the invention, they do not impair the usability of the pressurized compartment in any way. In manned aircraft with a cockpit, for example, cockpit accessibility can be ensured with a suitable arrangement. For this purpose, the cockpit can be located, in particular, above the tank. On the other hand, in unmanned aircraft, arranging the cryogenic tanks forward and aft of the center of gravity outside the pressurized compartment offers the advantage that the pressurized compartment can be used entirely as a cargo space, since the cryogenic tanks are out of the way. In an advantageous embodiment of the invention, a cross-sectional area of ​​the cryogenic tank is at least partially identical to a cross-sectional area of ​​the fuselage. Ideally, the walls of the cryogenic tank can even be identical to the outer walls of the fuselage.This results in optimal gravimetric efficiency.

[0014] In a further development of the invention, the pressure chamber has several decks. If the pressure chamber is a passenger pressure cabin, passengers can, for example, be accommodated on an upper deck and a lower deck. Since, according to the invention, the cryogenic tanks are arranged outside the pressure chamber, i.e., outside the pressure cabin, the accessibility of the decks is not impaired by the cryogenic tanks.

[0015] In a particularly advantageous embodiment of the aircraft according to the invention, a pressure bulkhead is arranged between the pressurized compartment and the cryogenic tank. The pressure bulkhead isolates the pressurized compartment, i.e., for example, the pressurized cabin, from the environment, and the cryogenic tank can be arranged directly adjacent to the pressure bulkhead.

[0016] In this embodiment of the invention, it is particularly advantageous if the pressure bulkhead has the properties of a fireproof wall.

[0017] To equip the aircraft according to the invention as a manned aircraft, a cockpit is provided in a preferred embodiment. The cockpit can be designed as a separate pressurized compartment. In this case, access to the cockpit from the pressurized compartment is not possible. According to the invention, the cockpit can also be unpressurized, or airlocks and / or a continuous pressure bulkhead can be provided.

[0018] In particular, according to a preferred embodiment, the cockpit is arranged in the pressurized space, specifically in the pressurized cabin. Since, according to the invention, the cryogenic tank is arranged outside the pressurized space, the cockpit is easily accessible within the pressurized cabin.

[0019] According to a particularly advantageous embodiment of the aircraft according to the invention, the cockpit is arranged above a cryogenic tank, preferably a cranial one, and the cockpit is preferably provided with a fire-resistant floor. In embodiments where the pressurized compartment has several decks, the cockpit can, according to this embodiment of the invention, be arranged on the upper deck, which is oriented towards the bow of the aircraft, in order to be positioned above the cranial cryogenic tank. If, in this embodiment, the cockpit is provided with a fire-resistant floor, the safety of the cockpit personnel is ensured while in the cockpit, even considering the cryogenic tank located below.

[0020] According to another advantageous embodiment of the invention, the cockpit is arranged behind the pressure bulkhead. In this embodiment, a fire-resistant floor is advantageously not required.

[0021] A compact design of the aircraft according to the invention is obtained in an embodiment of the invention if a system for the processing and distribution of the fuel stored in the cryogenic tank is provided between the cryogenic tank and the pressure bulkhead.

[0022] In one embodiment of the invention, the aircraft according to the invention has wings separate from the fuselage but connected to it. This results in a so-called tube-and-wing arrangement of the aircraft. In a special embodiment, a canard arrangement can also be provided. Within the scope of the invention, the aircraft can also, for example, have a blended wing body, in which the wings and fuselage form a seamless unit.

[0023] Within the scope of the invention, an arrangement of the cryogenic tank in the bow and / or in the stern is advantageous, since in particular the front tank is very easily accessible for maintenance.

[0024] The invention is described in a preferred embodiment by way of example with reference to a drawing, further advantageous details of which can be seen in the figures of the drawing.

[0025] Functionally identical parts are marked with the same reference symbols.

[0026] The figures in the drawing show, in detail: Fig. 1: Side view of a first embodiment of a flying object according to the invention; Fig. 2: Side view of a second embodiment of a flying object according to the invention; Fig. 3: Side view of a third embodiment of a flying object according to the invention; Fig. 4: Side view of a fourth embodiment of a flying object according to the invention; Fig. 5: Side view of a fifth embodiment of a flying object according to the invention.

[0027] Fig. Figure 1 schematically shows a side view of an aircraft according to the invention in a first embodiment in the form of a passenger aircraft 1. The passenger aircraft 1 is designed according to a "tube-and-wing" configuration of the "conventional" type. The passenger aircraft 1 has a fuselage 2 and main wings 2 extending substantially laterally from the fuselage 2. According to this embodiment, the main wings 2 are positioned as a low-wing monoplane. A propulsion system in the form of a gas turbine 3 is mounted below each main wing 2.

[0028] A pressurized cabin 4 is located in a central section of the hull 2. The pressurized cabin 4 is designed as a passenger compartment with an upper deck 5 and a lower deck 6. The pressurized cabin 4 is sealed off from the environment by a forward pressure bulkhead 7 and a rear pressure bulkhead 8.

[0029] In the area of ​​the bow 9 of the passenger aircraft 1, a cranial cryotank 11 for liquid hydrogen is arranged in the fuselage 10 outside the pressurized cabin 4, in which liquid hydrogen (LH2) is stored.

[0030] In the area of ​​the tail 12 of the passenger aircraft 1, a caudal cryotank 13 is arranged in the fuselage 10 outside the pressurized cabin 4, in which liquid hydrogen (LH2) is also stored.

[0031] Both the forward pressure bulkhead 7 and the rear pressure bulkhead 8 also serve as a fire protection wall against the cranial cryotank 11 and the caudal cryotank 13, respectively.

[0032] Systems for fuel processing and distribution are installed between cryogenic tanks 11 and 13 and their respective pressure bulkheads 7 and 8. These are not shown in the figures.

[0033] At the forward end of the upper deck 5 of the pressurized cabin 4, a cockpit 14 is arranged within it. The cockpit 14 is positioned to ensure sufficient forward visibility. This is shown in the embodiment according to Fig. 1. This ensures that the angle α between the longitudinal axis of the passenger aircraft 1 and a tangent from the cockpit to the nose 9 is α>18°. This guarantees forward visibility in accordance with applicable certification regulations, for example, FAA AC 25.773-1.

[0034] The Fig. Figure 2 schematically shows a side view of a second embodiment of a flying object according to the invention in the form of a passenger aircraft 101. The structure of the passenger aircraft 101 according to the second embodiment corresponds essentially to that of the passenger aircraft 1 according to the first embodiment with regard to the features of interest here. However, the passenger aircraft 101 differs from the passenger aircraft 1 according to the first embodiment. Fig. 1. The difference lies in the fact that the pressurized cabin 4 has only one passenger deck. In this configuration, the cockpit 14 is designed as a small additional deck. Even in this configuration, the cockpit 14 is part of the continuous pressurized cabin 4. The cockpit 14 is accessible via the passenger deck. The two cryogenic tanks 11, 12 do not obstruct access, as they are located outside the pressurized cabin 4. The fuel is conveyed to the gas turbines 9 via insulated fuel lines 15. The fuel lines 15 are only schematically indicated in the figures.

[0035] The Fig. Figure 3 again schematically shows a side view of a flying object according to the invention in a third embodiment, also in the form of a passenger aircraft 201. The passenger aircraft 201 is analogous to the passenger aircraft 101 with respect to the relevant features according to the invention. Fig. 2 constructed. It has a cranial cryotank 11 inside the hull 10 in the bow 9 in front of the pressure cabin 4 and a caudal cryotank 13 inside the hull 10 in the stern 12 behind the pressure cabin 4.

[0036] In contrast to the passenger aircraft 101 of the second embodiment according to Fig. 2 is on passenger aircraft 201 according to Fig. 3. The cockpit 314 is designed as a small additional deck. The printed area is extended over the cranial cryotank 11 by the cockpit 314. In this embodiment, the cockpit is also part of the pressure cabin 4, so that the cockpit 314 is accessible from the passenger compartment, without affecting the cryotanks 11, 13, which are arranged outside the pressure cabin 4 according to the invention. In this configuration, a cockpit floor 16 of the cockpit 314 has a fire resistance to ensure the safety of the cockpit personnel from the cryotank 11 located below the cockpit 314. The fire resistance is in the Fig. 3 not shown in detail.

[0037] The Fig. Figure 4 shows a schematic side view of a fourth embodiment of a flying object according to the invention in the form of an autonomously flying drone 301, which does not have a cockpit. Since no cockpit is required, in this embodiment the cranial cryotank 11 can completely fill the cross-section of the fuselage 10 in the nose 9 of the drone 301. This results in optimized gravimetric efficiency of the cryotank 11.

[0038] The Fig. Figure 5 schematically shows a fourth embodiment of a flying object according to the invention in the form of a cargo aircraft 401. The figure shows Fig. 5 (a) a perspective side view of cargo plane 401. Fig. Figure 5(b) shows a top view of the cargo aircraft 401. The cargo aircraft 401 provides ample access to the forward fuselage 10. For this purpose, the nose 9 of the fuselage 10 of the cargo aircraft 401 is designed as a movable cargo door 17. This design follows a modular philosophy. It allows for convenient fuel tank replacement and easy access for maintenance purposes.

[0039] The embodiment according to Fig. Figure 5 (a) shows the cargo door 17 both in a closed state - see dashed lines - and in a state opened upwards by flaps - see solid lines.

[0040] The embodiment according to Fig. Figure 5 (b) shows the cargo door 17 in a sideways opened position.

[0041] The cranial cryotank 11 is present in both embodiments of the Fig. 5 together with the forward pressure bulkhead 7 in the movable cargo door 17.

[0042] Cargo door 17 can be opened to the side or upwards. Fig. Figure 5(a) illustrates the upward opening of cargo door 17. Fig. Figure 5(b) illustrates the side opening of the cargo door 17. The cargo aircraft 401 is designed as a high-wing aircraft. It has a caudal cryotank 13 in the tail 12 outside the pressurized cabin 4 behind the rear pressure bulkhead 8.

[0043] The cargo door 17 can also be located at the rear and be hinged there, without leaving the framework of the invention. The cargo door 17 can also be provided with hinges that allow it to open in other directions, in particular downwards. These variants are not shown in the figures.

[0044] Because, in this embodiment of the invention, the cryogenic tanks are also arranged outside the pressure chamber, i.e., outside the pressure cabin 4, the cross-section of the cryogenic tanks 11, 13 can be adapted, at least partially, to the cross-section of the fuselage 10 in order to achieve particularly favorable gravimetric efficiency of the cryogenic tanks 11, 13. Above all, the addition of cryogenic tanks to a given aircraft design allows for targeted control of the center of gravity shift. In particular, the addition of cryogenic tanks can minimize center of gravity shift under different operating conditions. REFERENCE MARK LIST 1 passenger aircraft 2 main wings 3 Gas turbine 4 Pressure cabin 5 Upper deck 6 Lower deck 7 forward pressure bulkhead 8 rear pressure bulkhead 9 Bug 10 Hull 11 cranial cryotank 12 Rear 13 caudal cryotanks 14 Cockpit 101 passenger aircraft 15 Fuel line 201 passenger aircraft 16 Cockpit floor 301 Drone 314 Cockpit 401 Cargo Plane 17 Cargo door QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 4124568A1 [0004, 0005]

Claims

[1] Flying object (1, 101, 201, 301, 401) with a center of gravity, a fuselage (10), a pressure chamber (4) arranged in the fuselage (10), a propulsion system (3) operable with a cryogenic fuel (LH2) and at least one cryogenic tank (11, 13) connected to the fuselage (10) for storing the cryogenic fuel (LH2), characterized by , that the cryotank (11, 13) is arranged outside the pressure chamber (4). [2] Flying object (1, 101, 201, 301, 401) according to claim 1, characterized by that the cryogenic fuel (LH2) contains liquid hydrogen. [3] Flying object (1, 101, 201, 301, 401) according to claim 1 or 2, characterized by , that several cryotanks (11, 13) are provided. [4] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that the several cryotanks (11, 13) are arranged distributed over the flying object (1, 101, 201, 301, 401). [5] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that the cryotanks (11, 13) are arranged in such a way over the flying object (1, 101, 201, 301, 401) that their torques neutralize each other with respect to the center of gravity. [6] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that a cranial cryotank (11) arranged in front of the center of gravity and a caudal cryotank (13) arranged behind the center of gravity are provided. [7] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that a cross-sectional area of ​​the cryotank (11, 13) is at least partially identical to a cross-sectional area of ​​the hull (10). [8] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that the pressure chamber (4) has several decks (5, 6). [9] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by, that a pressure bulkhead (7, 8) is arranged between the pressure chamber (4) and the cryotank (11, 13). [10] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that the pressure bulkhead (7, 8) has properties of a fire wall. [11] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that a cockpit (14, 314) is provided. [12] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that the cockpit (14, 314) is located in the pressure chamber (4). [13] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that the cockpit (314) is arranged above a cryotank (11, 13), in particular a cranial one, wherein the cockpit (314) is preferably provided with a fireproof floor (16). [14] Flying object (1, 101, 201, 301, 401) according to claim 12, characterized by, that the cockpit (14, 314) is located behind the pressure bulkhead (7, 8). [15] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that a system for the treatment and distribution of the fuel (LH2) stored in the cryogenic tank (11, 13) is provided between the cryogenic tank (11, 13) and the pressure bulkhead (7, 8). [16] Flying object (1, 101, 201, 301, 401) according to any one of the preceding claims, characterized by , that it has separate wings connected to the fuselage (10).

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