FIELD OF THE INVENTION

[0001] The present invention relates to an aircraft wing with a fuel tank and a fuel cell. BACKGROUND OF THE INVENTION

[0002] A hydrogen energy fixed-wing aircraft is described in CN207631504 (U). Hydrogen fuel tanks are suspended under the wings via pylons, and fuel cell stacks are provided in the wings.

SUMMARY OF THE INVENTION

[0003] A first aspect of the invention provides an aircraft wing comprising: a wingbox; a fuel tank; a fuel cell system comprising a fuel cell; a fuel line configured to deliver fuel from the fuel tank to the fuel cell system; a propulsion system carried by the wingbox; and an electrical power line configured to deliver electrical power from the fuel cell system to the propulsion system, wherein the fuel tank and the fuel cell system are located inside the wingbox, and the propulsion system is located outside the wingbox.

[0004] Optionally the fuel tank is a hydrogen fuel tank.

[0005] Optionally the propulsion system is suspended under the wingbox.

[0006] Optionally the fuel cell system further comprises a battery.

[0007] Optionally the propulsion system comprises a motor.

[0008] Optionally the propulsion system comprises a power control unit.

[0009] Optionally the propulsion system comprises a propeller.

[0010] Optionally the electrical power line is flexible.

[0011] Optionally the wingbox comprises an upper cover; a lower cover; a front spar and a rear spar.

[0012] Optionally the electrical power line passes through the front spar or the rear spar. [0013] Optionally the propulsion system is carried by a pylon. [0014] Optionally the fuel tank is cylindrical.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

[0016] Figure 1 is a plan view of an aircraft;

[0017] Figure 2 is a front view of the aircraft of Figure 1;

[0018] Figure 3 is a plan view of the port wing showing the fuel cell system and propulsion system; and

[0019] Figure 4 is an isometric view of part of the wingbox with the upper cover removed.

DETAILED DESCRIPTION OF EMBODIMENT(S)

[0020] An aircraft 1 shown in Figures 1 and 2 comprises a fuselage 2 and a pair of wings 3, 4. Each wing comprises a wingbox 5, comprising an upper cover 10, a lower cover 11, a front spar 12 and a rear spar 13.

[0021] The upper cover 10 is shown in Figure 1, and part of the wingbox 5 is shown in Figure 4 with the upper cover 10 removed to make the internal parts visible. Figure 3 is a plan view of the port wing with various internal parts shown.

[0022] The wingbox 5 contains a plurality of ribs which divide the wingbox into bays. Each of the ribs is attached to both of the covers 10, 11 and to both of the spars 12, 13. Two of the ribs are labelled 14 and shown in Figure 4.

[0023] A plurality of cylindrical hydrogen fuel tanks are located inside the wingbox 5. The fuel tanks are not shown Figure 3, and Figure 4 shows only two of the hydrogen fuel tanks 20, 21. In this example each fuel tank 20, 21 is located inside a respective bay 20a, 21a between a pair of ribs. The wingbox 5 may contain further hydrogen fuel tanks (not shown) each housed within a respective bay. In an alternative embodiment, the hydrogen fuel tanks may run in a spanwise direction, passing through the ribs.

[0024] In this example, the wingbox houses multiple fuel tanks 20, 21, but in an alternative embodiment it may house only a single fuel tank. [0025] A fuel cell system 30 is also located inside the wingbox 5, in a bay between the pair of the ribs 14 shown in Figure 4. The fuel cell system 30 comprises a fuel cell 32 and a battery 33. A first fuel line 40 is configured to deliver hydrogen fuel from the fuel tank 20 to the fuel cell system 30, and a second fuel line 41 is configured to deliver hydrogen fuel from the fuel tank 21 to the fuel cell system 30.

[0026] The fuel cell 32 is an electrochemical cell (or stack of cells) which converts chemical energy of the hydrogen fuel into electrical energy which is stored in the battery 33.

[0027] A propulsion system 50 is carried by the wingbox 5. As shown in Figure 3, the propulsion system 50 is located outside the wingbox 5. The propulsion system 50 comprises a power control unit 51, a motor 52 and a shrouded propeller 53.

[0028] In this example the propulsion system 50 is suspended under the wingbox 5 by a pylon 53 shown in Figure 3. In an alternative embodiment the propulsion system 50 may be located over the wingbox 5, or carried by the wingbox in any other position.

[0029] An electrical power line 60 is configured to deliver electrical power from the fuel cell system 30 to the propulsion system 50. A power control unit 51 is configured to receive electrical power from the battery, and a control input from the pilot, and output electrical power accordingly to the motor 52. The motor 52 is configured to convert the electrical power from the power control unit 51 into motion which it transmits to the propeller or turbine 53.

[0030] In this example the electrical power line 60 passes through the front spar 12, but in an alternative embodiment the electrical power line 60 may pass through the rear spar 13 or through any other part of the wingbox 5.

[0031] During flight of the aircraft 1, there may be a large amount of relative motion between the propulsion system 50 and the wingbox 5. The electrical power line 60 is flexible so that it can flex to accommodate this relative motion without being excessively damaged.

[0032] Locating the fuel cell system 30 inside the wingbox 5 means that the hydrogen fuel lines 40, 41 do not need to accommodate this relative motion. [0033] In the example described above, the fuel tanks 20, 21 are hydrogen fuel tanks, but in other examples the fuel tanks may contain any other type of fuel which can be used by a fuel cell to convert chemical energy into electrical energy.

[0034] In summary, the embodiment of the invention described above provides an aircraft wing 3 comprising: a wingbox 5; one or more fuel tanks 20, 21; a fuel cell system 30 comprising a fuel cell 32; one or more fuel lines 40, 41 configured to deliver fuel from the fuel tanks to the fuel cell system; a propulsion system 50 carried by the wingbox 5; and an electrical power line 60 configured to deliver electrical power from the fuel cell system 30 to the propulsion system 50. The fuel tank(s) 20, 21 and the fuel cell system 30 are located inside the wingbox, and the propulsion system 50 is located outside the wingbox.

[0035] This arrangement has several advantages compared with CN207631504 (U). Firstly, it should be noted that the aircraft in CN207631504 (U) has a propeller mounted on the nose of its fuselage, but there is no disclosure of the propeller being driven by the fuel cell stacks. Thus a first advantage is that a propulsion system 50 is provided which is powered by electrical power from the fuel cell. Secondly, the hydrogen fuel lines between the fuel tanks and the fuel cells in CN207631504 (U) must accommodate relative motion between the wing and the fuel tanks suspended under the wing. A second advantage is that such motion does not need to be accommodated by the hydrogen fuel lines 40, 41, making them less prone to rupture. A third advantage is that by locating the fuel tank 20, 21 in the wingbox 5, it is less exposed to the risk of damage. A fourth advantage is that the wing-mounted propulsion system 50 is close to the fuel cell system 30, making the arrangement compact. The wing-mounted propulsion system 50 also provides various other advantages, such as improved flight handling and easier inspection or repair of the propulsion system 50 when the aircraft is on the ground.

[0036] Where the word 'or' appears this is to be construed to mean 'and/or' such that items referred to are not necessarily mutually exclusive and may be used in any appropriate combination. [0037] Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.