Blended wing body aircraft with all-electric propulsion

Abstract

The present invention relates to an aircraft (1) comprising: a main fuselage formed by a central wing (10), centred on a longitudinal axis (X10); two lateral wings (20) mechanically connected to the central wing (10); and at least one propulsion system (40); characterized in that the aircraft (1) comprises an electrical energy storage system (30) electrically connected to the propulsion system (40) and providing all-electric propulsion for the aircraft (1).

Description

[0001] Aircraft with integrated fuselage and all-electric propulsion

[0002] technical field

[0003] The present invention relates to a blended wing body (BWB) aircraft with all-electric propulsion. The field of the invention is that of air transport for passengers and / or cargo.

[0004] Previous art

[0005] Different aircraft architectures are known to date.

[0006] The cylindrical / cigar-shaped fuselage with two lateral wings is the most common design. This architecture has met the need for long-distance, subsonic flights for decades. However, it also presents significant drawbacks. The wings have small lift surfaces, requiring large airports and leading to numerous logistical and boarding complexities. The wings also have a limited wingspan to facilitate parking at terminals and maneuvering on the ground with minimal difficulty. For example, some large-capacity aircraft models have required extensive airport upgrades or redesigns in various countries.The small fuselage, designed to reduce drag, and its nearly circular cross-section, which supports pressurization, sometimes make life on board very uncomfortable (feelings of suffocation, risk of claustrophobia, difficult movement for crew and passengers, complex cabin layout). The concentration of mass in the fuselage, relative to its small dimensions, results in a very high empty weight. The empty weight to takeoff weight ratio is often between 0.5 and 0.6, meaning that nearly 50% of the propulsion power (related to fuel consumption) is not used for passenger transport.

[0007] The so-called flying wing architecture, generally with a large wingspan, incorporates a sweep to address longitudinal stability issues. This design generates the lowest drag and offers a higher lift-to-drag ratio. Passengers are housed within the wing's profile, but the wingspan must be significantly increased. However, this makes ground operations more difficult. Furthermore, the non-cylindrical cabin volumes complicate the structural design. Finally, thanks to efficient mass distribution, the empty weight to takeoff weight ratio is approximately 0.4.

[0008] The blended wing body (BWB) design has been studied particularly for transonic flight, featuring a central wing (body) and fixed lateral wings. Such an aircraft lacks sweep but nevertheless exhibits excellent longitudinal stability thanks to its special wing profile. Document WO2021123540 describes an example of a BWB aircraft and its advantages. This aircraft can be powered by electricity, internal combustion, or hybrid propulsion.

[0009] US2023348089A1 describes another example of a BWB aircraft and its advantages. This aircraft can be either thermal or hybrid powered. The aircraft includes a fuel tank for storing liquefied gaseous fuel.

[0010] CN112722262 and US10040547B1 describe examples of BWB (bottom-body) drones. These drones have vertically propelled rotors for takeoff and landing, integrated into the fuselage. This imposes specific constraints on the design of the propulsion systems and the fuselage. In particular, it is necessary to equip the aircraft with a separate propulsion system for cruise flight. Furthermore, this creates weak points in the fuselage.

[0011] Description of the invention

[0012] The aim of the present invention is to provide an improved aircraft.

[0013] To this end, the invention relates to an aircraft comprising:

[0014] - a main fuselage consisting of a central wing, centered on a longitudinal axis;

[0015] - two lateral wings mechanically connected to the central wing; and

[0016] - at least one propulsion system; characterized in that the aircraft includes an electric battery system electrically connected to the propulsion system and providing fully electric propulsion of the aircraft.

[0017] Thus, the invention makes it possible to propose a new generation of BWB aircraft, meeting current environmental challenges. These aircraft can be optimized in terms of propulsion, aerodynamics, stability, compactness, flight speed, operating radius, short takeoff / landing capability, and payload. Other advantageous features of the invention, considered individually or in combination, include:

[0018] - The propulsion system comprises: a fairing; a nozzle located at the rear of the fairing and centered on a nozzle axis; a drive shaft located in the fairing and centered on a drive axis; and a shrouded propeller, mounted on the drive shaft inside the fairing.

[0019] - The nozzle axis is inclined relative to the motor axis, with an angle formed between the nozzle axis and the motor axis which is between 1 and 30 degrees, for example equal to 20 degrees.

[0020] According to different variations:

[0021] - The nozzle axis is inclined upwards relative to the engine axis.

[0022] - The nozzle axis is inclined to the side relative to the engine axis.

[0023] - The nozzle axis is inclined downwards relative to the engine axis.

[0024] - The nozzle axis is inclined upwards and to the side relative to the motor axis.

[0025] - The nozzle axis is inclined downwards and to the side relative to the motor axis.

[0026] - In the lower part, the fairing is integral with the central wing.

[0027] - The aircraft has a tail fin mounted on the fairing.

[0028] - The propulsion system includes a control surface positioned in line with the nozzle.

[0029] - The control surface is housed partly inside the nozzle and partly outside the nozzle.

[0030] - The rudder is mounted on a pivot axis having a lower end housed in the lower part of the fairing, an intermediate section housed in the upper part of the fairing, and an upper end housed in the fin.

[0031] - The rudder has a lower part located in line with the nozzle and an upper part located in line with the fin, above the fairing.

[0032] - Between the lower and upper parts, the rudder has an intermediate hollowed-out part which receives the fairing in the upper part.

[0033] - The central wing has a hollow area formed in front of the propulsion system for air intake and having a profile in tangency with the propulsion system.

[0034] - At least one propulsion system is positioned on the central wing.

[0035] - The aircraft comprises two propulsion systems mounted on the central wing, respectively to the left and right of a vertical central plane of the aircraft. - The propulsion system comprises a nacelle; a drive shaft located in the nacelle and centered on a drive axis; an unfaired propeller mounted on the drive shaft, at the front of the nacelle; and a mast supporting the nacelle.

[0036] - The aircraft lacks a vertical propulsion rotor.

[0037] - The aircraft lacks a rotor integrated into the fuselage.

[0038] - The central wing lacks a vertical propulsion rotor.

[0039] - The front part of the central wing lacks a rotor integrated into the fuselage.

[0040] - The lateral wings are devoid of vertical propulsion rotors.

[0041] - The lateral wings lack rotors integrated into the fuselage.

[0042] - The propulsion system is positioned on the central wing.

[0043] - The propulsion system includes a propeller only in the rear part of the central wing.

[0044] - The central wing has a rear door.

[0045] - The rear door is located between the two propulsion systems.

[0046] - Preferably, the aircraft is configured for passenger transport.

[0047] - Ideally, the aircraft can be configured to carry between 10 and 30 passengers.

[0048] Description of the figures

[0049] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0050] - Figure 1 is a perspective view from the front of an aircraft according to the invention.

[0051] - Figure 2 is a perspective view from the rear of the aircraft in Figure 1.

[0052] - Figure 3 is a top view of the aircraft in Figure 1.

[0053] - Figure 4 is a rear view of the aircraft in Figure 1.

[0054] - Figure 5 is a rear side perspective view showing the rear part of the aircraft of Figure 1, in particular its propulsion systems.

[0055] - Figure 6 is a partial view of the rear part of the aircraft, on the left side of Figure 5, showing one of the propulsion systems.

[0056] - Figure 7 is a cross-section along line VII-VII in figure 6, showing the propulsion system.

[0057] - Figure 8 is a cross-section similar to Figure 6, showing different positions of the control surface equipping the propulsion system. - Figure 9 is a top view of the propulsion system shown in Figure 6.

[0058] - Figure 10 is a cross-section along line XX in Figure 9, showing the propulsion system.

[0059] - Figure 11 is a top view similar to figure 9, from a different angle and partially transparent, with the rudder on the left side.

[0060] - Figure 12 is a top view similar to figure 11, with the rudder on the right side.

[0061] - Figure 13 is a rear perspective view of an aircraft conforming to a second embodiment of the invention.

[0062] - Figure 14 is a top view of the aircraft in Figure 13.

[0063] - Figure 15 is a rear view of the aircraft in Figure 13.

[0064] - Figure 16 is a view of the left side of the aircraft in Figure 13.

[0065] Detailed description of the invention

[0066] Figures 1 to 12 show a BWB-type aircraft (1) according to the invention, having a longitudinal axis (X10) or roll axis, a transverse axis (Y10) or pitch axis, and a vertical axis (Z10) or yaw axis. The aircraft (1) comprises a main fuselage formed by a central wing (10), centered on the longitudinal axis (X10); and two lateral wings (20) mechanically connected to the central wing (10), on either side of the vertical median plane (Pxz). In various embodiments, the lateral wings (20) may be fixed to the central wing (10) or pivotal relative to the central wing (10).

[0067] With reference to Figure 3, the aircraft (1) may have a length Long of between 4 and 20 meters, for example 12 meters, and a wingspan Env of between 10 and 60 meters, for example 33 meters. Preferably, the ratio between the wingspan Env and the length Long is between 1.5 and 4.

[0068] The aircraft's BWB architecture (1) allows for a more uniform distribution of aerodynamic lift forces. Since the central wing (10) is load-bearing, the wings (20) do not need to provide as much lift as in a tubular-fuselage aircraft. Consequently, the bending moments transmitted from the wings (20) to the fuselage are less intense. Furthermore, the large wing cross-section (20) at the fuselage junction prevents excessive stress concentration. These characteristics simplify the load transfer and thus allow for two things: a reduction in the structure's mass or longer wings (20).

[0069] Thanks to its integrated fuselage architecture and high-performance composite materials, the aircraft (1) can be designed with a wingspan exceeding 33 meters and can carry up to 19 passengers. The wingspan-to-passenger ratio therefore exceeds the threshold of 1.7.

[0070] The aircraft (1) can be used for passenger transport, freight transport, rapid rescue operations and military operations, reducing the energy requirements associated with its activities.

[0071] Furthermore, the aircraft (1) is designed using the "cross-layout" method, a geometric method for defining the position of the lateral wings (20) on the central wing (10) within the framework of defining a BWB aircraft. More specifically, the cross-layout method defines the position of the wing root of the lateral wings (20) relative to the chord of the central wing (10) of the aircraft (1). Depending on the airfoils used on the central wing (10), the position of the root can vary; it will therefore be expressed as a percentage of the chord, with point 0 being the nose of the aircraft (1). Preferably, the root is located at 70% of the chord, but can vary from 50% to 100% depending on the choice of wing airfoil (10, 20).

[0072] The aircraft (1) includes an electrical energy storage system (30) and two propulsion systems (40) electrically connected to the electric battery system (30). The electrical energy storage system (30) may include batteries, capacitors, capacitors, flywheels, or any other suitable means.

[0073] The system (30) is located in the central wing (10). The system (30) provides fully electric propulsion for the aircraft (1). In other words, the aircraft (1) has no thermal or hybrid propulsion.

[0074] The two propulsion systems (40) are mounted on the central wing (10), respectively to the left and right of the vertical central plane (Pxz) of the aircraft (1), symmetrically with respect to this plane (Pxz). A spacing E40 is provided between the two propulsion systems (40). As an example, this spacing (E40) can be between 2 and 20 meters.

[0075] Each propulsion system (40) comprises a fairing (41); a nozzle (42) located at the rear of the fairing (41) and centered on a nozzle axis (A42); a drive shaft (43) located within the fairing (41) and centered on a drive axis (A43); and a shrouded propeller (44) mounted on the drive shaft (43) inside the fairing (41). The components of the system (40) do not protrude beyond the nozzle (42) at the rear. The nozzle (42) can be secured to the fairing (41) by any suitable means; for example, the nozzle (42) can be a component mounted on the rear of the fairing (41).

[0076] In the embodiment shown in Figures 1 to 12, the nozzle axis (A42) is inclined upwards relative to the engine axis (A43), with an angle (c) formed between the nozzle axis (A42) and the engine axis (A43) that is between 1 and 30 degrees, for example, 20 degrees. The angle (c) of the nozzle (42) compensates for the pitching moment generated on the nose of the aircraft (1) by the power and position of the propulsion systems (40).

[0077] In various unshown configurations, the nozzle axis (A42) can be inclined in different ways relative to the engine axis (A43): sideways, downwards, upwards and sideways, or downwards and sideways. In all cases, the nozzle axis (A42) is located within a cone defined by an angle between 1 and 30 degrees relative to the engine axis (A43). The sideways angled nozzle (A42) compensates for yaw torque.

[0078] Advantageously, the nozzle axis (42) is offset from the aircraft's center of gravity (1). This offset between the nozzle axis (42) and the axis (X10) in the vertical plane (Pxz) helps reduce the nose-down moment generated around the pitch axis (Y10), that is, the moment that tends to make the aircraft (1) nose-down, compared to a configuration without this offset. This is particularly advantageous during takeoff. Similarly, the offset between the nozzle axis (A42) and the axis (X10) in the horizontal plane (Pxy) helps reduce the moment generated around the yaw axis (Z10) compared to a configuration without this offset. This moment tends to make the nose of the aircraft (1) point in the direction opposite the propulsion system—port or starboard. This makes it easier to maintain control of the aircraft (1) in the event of the loss of a propulsion system (40).

[0079] In its lower section, the fairing (41) is integral with the central wing (10). This allows the propulsion axis, corresponding to the nozzle axis (A42), to be lowered, thus reducing the parasitic pitching moment exerted on the nose of the aircraft (1). Furthermore, this lightens the aircraft structure (1), which reduces propulsion energy consumption and moves the center of gravity forward, thereby improving stability.

[0080] The aircraft (1) has a fin (50) mounted on the fairing (41). This configuration is much more responsive to crosswinds than a cylindrical fairing without a fin, which improves lateral (yaw) stability.

[0081] The propulsion system (40) includes a control surface (60) positioned in line with the nozzle (42). The control surface (60) is blown by the air exiting the nozzle (42). The blown control surface (60) improves lateral control at low speeds, therefore during takeoff and landing. Furthermore, in the event of a failure of one of the propulsion systems (40), the thrust direction of the remaining system (40) reduces the parasitic yaw moment induced by the thrust itself, thus improving aircraft control (1). Finally, the positioning of the control surface (60) above the slow boundary layer improves aircraft stability (1).

[0082] In the embodiment shown in Figures 1 to 12, the control surface (60) is partially housed within the nozzle (42) and partially outside the nozzle (42). The control surface (60) is mounted on a pivot axis (61) having a lower end (611) housed in the lower part of the fairing (41), an intermediate section (612) housed in the upper part of the fairing (41), and an upper end (613) housed in the fin (50). The control surface (60) has a lower portion (66) located in line with the nozzle (42) and an upper portion (67) located in line with the fin (50), above the fairing (41). Between the lower portion (66) and the upper portion (67), the control surface (60) has a hollowed-out intermediate portion (67) receiving the fairing (41) at its upper end.

[0083] According to unshown variants, the control surface (60) could be entirely within the nozzle (42), or entirely outside the nozzle (42). The central wing (10) has a hollow area (16) formed in front of the propulsion system (40) for air intake. The hollow area (16) has a profile tangent to the propulsion system (40). The fairing (41) has a cutout (416) above the hollow area (16). This allows for better distribution of the load transfer, and therefore a reduction in the weight of the central wing (10).

[0084] The central wing (10) has a rear door (80) for boarding passengers or cargo. The rear door (80) is located between the two propulsion systems (40), as shown in Figure 4.

[0085] Figures 13 to 16 show another aircraft (1) of the BWB type, according to the invention. The aircraft (1) is equipped with two propulsion systems (40), each comprising:

[0086] - a gondola (45);

[0087] - a drive shaft (43) disposed in the nacelle (45) and centered on a drive shaft (A43);

[0088] - an unfaired propeller (46) mounted on the drive shaft (43), at the front of the nacelle (45); and

[0089] - a mast (47) supporting the gondola (45).

[0090] The motor axis (A43) is inclined with respect to the horizontal plane (Pxy), with an angle formed between the motor axis (A42) and the horizontal plane (Pxy) which is between 1 and 30 degrees, for example equal to 20 degrees.

[0091] Preferably, the motor axis (A43) is inclined at the rear of the aircraft (1) upwards relative to the horizontal plane (Pxy).

[0092] The aircraft (1) includes an electrical energy storage system (30) electrically connected to the propulsion systems (40) and providing fully electric propulsion for the aircraft (1)

[0093] Furthermore, the aircraft (1) can be configured differently from Figures 1 to 16 without departing from the scope of the invention, which is defined by the claims. In particular, the propulsion system (40) can have any configuration suitable for the intended application. Moreover, the technical features of the various embodiments and variants mentioned above can be combined, in whole or in part. Thus, the aircraft (1) can be adapted in terms of cost, functionality, and performance.

Claims

Demands 1) Aircraft (1) comprising: - a main fuselage consisting of a central wing (10), centered on a longitudinal axis (X10); - two lateral wings (20) mechanically connected to the central wing (10); and - at least one propulsion system (40); characterized in that the aircraft (1) includes an electrical energy storage system (30) electrically connected to the propulsion system (40) and providing fully electric propulsion of the aircraft (1). 2) Aircraft (1) according to claim 1, characterized in that the propulsion system (40) comprises: - a fairing (41); - a nozzle (42) arranged at the rear of the fairing (41) and centered on a nozzle axis (A42); - a drive shaft (43) disposed in the fairing (41) and centered on a drive axis (A43); and - a shrouded propeller (44), mounted on the drive shaft (43) inside the shroud (41). 3) Aircraft (1) according to claim 2, characterized in that the nozzle axis (A42) is inclined with respect to the engine axis (A43), with an angle (c) formed between the nozzle axis (A42) and the engine axis (A43) which is between 1 and 30 degrees, for example equal to 20 degrees. 4) Aircraft (1) according to claim 3, characterized in that the nozzle axis (A42) is inclined upwards with respect to the engine axis (A43). 5) Aircraft (1) according to any one of claims 2 to 4, characterized in that in the lower part, the fairing (41) is integral with the central wing (10). 6) Aircraft (1) according to any one of claims 2 to 5, characterized in that it comprises a fin (50) mounted on the fairing (41). 7) Aircraft (1) according to any one of claims 2 to 6, characterized in that the propulsion system (40) comprises a rudder (60) positioned in the extension of the nozzle (42). 8) Aircraft (1) according to any one of the preceding claims, characterized in that the central wing (10) has a hollow area (16) formed in front of the propulsion system (40) for the air intake and having a profile in tangency with the propulsion system (40). 9) Aircraft (1) according to claim 1, characterized in that the propulsion system (40) comprises: - a gondola (45); - a drive shaft (43) disposed in the nacelle (45) and centered on a drive shaft (A43); - an unfaired propeller (46) mounted on the drive shaft (43), at the front of the nacelle (45); and - a mast (47) supporting the gondola (45). 10) Aircraft (1) according to any one of the preceding claims, characterized in that the aircraft (1) is devoid of a vertical propulsion rotor. 11) Aircraft (1) according to any one of the preceding claims, characterized in that the central wing (10) is devoid of a vertical propulsion rotor. 12) Aircraft (1) according to any one of the preceding claims, characterized in that the lateral wings (20) are devoid of vertical propulsion rotors. 13) Aircraft (1) according to any one of the preceding claims, characterized in that the propulsion system (40) is positioned on the central wing (10). 14) Aircraft (1) according to any one of the preceding claims, characterized in that the propulsion system (40) comprises a propeller (44; 46) only in the rear part of the central wing (10). 15) Aircraft (1) according to any one of the preceding claims, characterized in that it comprises two propulsion systems (40) mounted on the central wing (10), respectively to the left and right of a vertical central plane (Pxz) of the aircraft (1).

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