An electrically propelled aircraft comprising a central wing and two rotatable side wings

Abstract

The invention relates to an aircraft (100) comprising a central wing (1) for accommodating passengers and / or cargo and two side wings (2, 2') pivoting on the central wing (1) about respective axes of rotation (3; 3'), these individual wings (1; 2, 2') complying with the following geometrical properties: -L arg is the distance between the two axes (3, 3'), ‑L ong is the length of the central wing (1), ‑Haut is the height of the central wing (1), ‑Env is the wingspan of the aircraft (100), characterized in that: ‑0.3×L ong < Larg <L ong , ‑0.11×Long <Haut<0.25×L ong ,‑E nv >1.4×L ong , and the rotation axis (3, 3') is inclined at a certain angle relative to the vertical axis of the aircraft (100), so that the side wings (2, 2') are pivoted from rear to front, or vice versa, to get closer to the fuselage or to be deployed from the fuselage on both sides.

Description

Technical Field

[0001] The invention relates to an electric-propelled aircraft comprising a central wing and two rotatable side wings. The electric-propelled aircraft is particularly suitable for air transportation of passengers or cargo. Background Art

[0002] Very different aircraft architectures coexisted until 1945, especially large seaplanes. The advent of jet engines and the increase in aircraft reliability led to a trend towards a single architecture. The elliptical fuselage of a generally cylindrical type with two side wings and a tail constituted the main form retained after the war. The main pursuit was speed, and everything was designed to allow the aircraft to move as quickly as possible, especially for crossing the Atlantic. In line with this trend, aircraft architectures were standardized with the goal of speeds of 800 km / h to 1000 km / h (below the sound barrier). The standard paved runway length of airports had to be adjusted to 2 km to 4 km, and aircraft were pressurized to fly at altitudes of more than 10,000 meters.

[0003] Manufacturers of fixed-wing aircraft (as opposed to helicopters) find themselves facing four basic technical demands worldwide: flight speed, shorter take-off and landing distances, more passengers, and longer ranges. In addition, there are economic and ecological constraints.

[0004] The need for faster flight can be met by using powerful motors, but these powerful motors result in a reduction in the distance traveled. Drag ( ) essentially due to friction in the air constitutes an obstacle to be overcome. Therefore, the outer surface (wet surface) of the aircraft, especially the outer surface of the wings and the outer surface of the fuselage, needs to be reduced as much as possible.

[0005] For the requirement of shortened take-off and / or landing distances, the weight of the aircraft, the wing surface and some appendages (flaps or high-lift slat-type appendages) are key parameters.

[0006] The need to accommodate the desired number of passengers (or even cargo) is obviously related to the size of the aircraft and the layout of its cabin. In this field, many efforts have been made to optimize the ratio of number of passengers / cabin size, but there is no doubt that the limits are close to being reached for optimal flight comfort.

[0007] Finally, with regard to the possibility of flying considerable distances, the maximum distance is obtained by flying the aircraft at its maximum fineness ratio (ratio of lift to aerodynamic drag) and at the lowest possible gross weight. In theory, the maximum fineness ratio is obtained when the friction drag is equal to the induced drag (drag induced by lift). Moreover, the value of this maximum fineness ratio is increased by reducing both types of drag.

[0008] The most commonly used aircraft architectures are as follows:

[0009] - Cylindrical / cigar-shaped fuselage architecture with two lateral wings. This architecture responds worldwide and for decades to the need to fly long distances at subsonic speeds. However, this architecture generates significant disadvantages. The wings of this architecture have low-lift surfaces, which require large airports and lead to many logistical and boarding complexities. The span of these wings is also limited in order to easily park at the terminal and to be displaced on the ground with the least possible difficulty. For example, some large-capacity aircraft models require extensive airport development / reconstruction in various countries. The small size of the fuselage (necessary to reduce drag) and its generally circular cross-section (supporting pressurization) make life on board sometimes very uncomfortable (feeling of suffocation, risk of claustrophobia, complex dislocation of staff and passengers, complex cabin layout). The concentration of the weight carried in the fuselage relative to the small size leads to a very high empty weight. The ratio of empty weight to take-off weight is usually between 0.5 and 0.6, which means that almost 50% of the propulsive power (related to the consumption of the carried fuel) is not used to transport passengers;

[0010] - The so-called flying wing architecture, usually with a (very) large span, includes a winglet to solve the problem of longitudinal stability. The resulting drag is the lowest and this solution provides a better slenderness ratio. The passengers are accommodated in the thickness of the wing section, but the span must be significantly enlarged.

[0011] However, ground handling is not very easy. Moreover, the non-cylindrical passenger cabin volume makes the construction of the structure more complicated. Finally, due to good weight distribution, the ratio of empty weight to take-off weight is about 0.4;

[0012] - Hybrid architectures called "Blended Wing Body" (BWB) architectures have been developed, in particular for transonic flight, having a central wing (body) and fixed side wings (wings). Patent US 6 264 136 B1 has proposed a BWB-type aircraft architecture comprising side wings whose angle of attack is variable relative to the central wing (body).

[0013] Furthermore, after World War II, seaplanes have undergone little improvement. The aerodynamic drag caused by the equipment required to operate on the water, such as the hull and stepped fuselage, and the floats, has limited the development of this type of equipment for commercial aviation. More recently, solutions for taking off and landing on the water using hydrofoils have been proposed in patents FR 2 902 079 and FR 2 970 699.

[0014] However, all these aircraft have not yet been optimized with regard to their aerodynamics, their stability, their compactness, their flight speed, their operating radius, their possibility of taking off / landing in short distances or their payload. Summary of the invention

[0015] The present invention aims to overcome these drawbacks in a completely innovative way, in particular as regards the architecture and the propulsion means.

[0016] To this end, according to a first aspect, the invention relates to an aircraft comprising a main fuselage consisting of a central wing for accommodating passengers and / or cargo, two side wings pivoted on the central wing about respective axes of rotation, each wing obeying the following geometrical characteristics:

[0017] -L arg is the distance between the two rotation axes of the pivoting flanks,

[0018] -L ong is the length of the central wing,

[0019] -H aut is the height of the central wing,

[0020] -E nv is the wingspan of the aircraft,

[0021] Features:

[0022] - 0.3 × L ong < L arg < L ong ,

[0023] - 0.11 × L ong < H aut < 0.25 × L ong ,

[0024] -E nv > 1.4 × L ong ,and

[0025] - The rotation axis of the wing is inclined at an angle β relative to the vertical axis Z of the aircraft, for example 10° < β < 50°, so that the wing pivots from rear to front and vice versa to get closer to the main wing or to deploy from it on both sides.

[0026] The invention is implemented according to the embodiments and variants set forth below, which should be considered individually or in any technically operational combination.

[0027] Advantageously, the lateral wings each comprise at least one aerodynamic control surface.

[0028] According to a particular embodiment of the invention, the wings pivot about their respective axes of rotation between a first extreme deployed flight position and a second extreme folded storage position of the aircraft, the magnitude of the angle Ω between these two extreme positions being approximately 70°.

[0029] In a complementary manner, the wings pivot about their respective axes of rotation between a first extreme deployed flight position and a second deployed centered take-off and / or landing position, the magnitude of the angle Ω between these two positions being approximately 40°.

[0030] According to a preferred embodiment of the invention, the aircraft comprises at least one pylon above the central wing, supporting at least one electric and / or thermal propulsion device and integrating at least one aerodynamic control surface.

[0031] According to a particularly interesting aspect of the invention, the aircraft comprises at least two hydrofoils beneath a central wing and retractable in said central wing.

[0032] Preferably, the aircraft is equipped with at least one door at the rear and / or front of the central wing.

[0033] Advantageously, the aircraft is provided with at least one cockpit on top of the central wing and at the level of the lateral wings.

[0034] According to a complementary feature of the invention, the aircraft comprises an emergency parachute inside the central wing. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other advantages, objects and features of the invention will emerge from the following description, given for illustrative and non-limiting purposes, with reference to the accompanying drawings, in which:

[0036] [ Figure 1 ] Figure 1 is a front top perspective view of a 24-inch aircraft according to the present invention, wherein the wings are in a horizontal flight position, and an X, Y, Z coordinate system is shown,

[0037] [ Figure 2 ] Figure 2 is similar to Figure 1 with the wings partially folded forward, in the flight position during the landing and / or take-off phases of the aircraft,

[0038] [ Figure 3 ] Figure 3 is similar to Figure 1 , with the wings fully folded forward in the storage position,

[0039] [ Figure 4 ] Figure 4yes Figure 1 A top view of the aircraft.

[0040] [ Figure 5 ] Figure 5 It's the foil ailerons extended Figure 4 A side view of an aircraft.

[0041] [ Figure 6 ] Figure 6 yes Figure 5 A front view of the aircraft, and

[0042] [ Figure 7 ] Figure 7 yes Figures 1 to 6 A detailed view of a variant of the aircraft's pylons. DETAILED DESCRIPTION

[0043] Figures 1 to 7 An aircraft 100 according to the invention is shown, preferably with electric or hybrid propulsion.

[0044] This aircraft 100 comprises a central wing 1 forming a fuselage for transporting passengers and / or cargo, and two lateral wings 2 and 2'. These wings can be pivoted about respective axes of rotation 3 and 3' to adopt different positions, which will be described later.

[0045] The general shape of the aircraft 100, and in particular of the wings 1, 2 and 2', is of a known type and complies with the following geometrical considerations:

[0046] -L arg is the distance between the two axes of rotation 3 and 3 ′ of the pivoting flanks 2 and 2 ′,

[0047] -L ong is the length of the central wing 1,

[0048] -H aut is the height of the central wing 1,

[0049] -E nv is the wingspan of aircraft 100 .

[0050] According to the invention, these geometrical properties must satisfy the following conditions:

[0051] - 0.3 × L ong < L arg < L ong ,

[0052] - 0.11 × L ong < H aut < 0.25 × L ong ,

[0053] -E nv > 1.4 × L ong .

[0054] Two axes 3 and 3' located in the transition zones 4 and 4' between the central wing 1 and the lateral wings 2 and 2' allow each of the lateral wings 2 and 2' to pivot. The axes 3 and 3' are located in these zones 4 and 4' of high thickness to support the lift generated by the lateral wings 2 and 2' on the fuselage.

[0055] like Figure 1 As shown, the axes 3 and 3' are inclined at an angle β relative to the vertical direction Z. The rotation of the wings 2 and 2' around the axes 3 and 3' by an angle Ω gives rise to the following considerations:

[0056] - for the angle of rotation -40° < Ω < +40°: the variation in flight of the relative aerodynamic angle of attack between the lateral wings 2 and 2 ′ and the central wing 1 is accompanied by a change in the aerodynamic thrust centre along the longitudinal axis X of the aircraft;

[0057] - For a rotation angle of Ω > 70° or Ω < -70°: stow wings 2 and 2' forwards or backwards, especially on the ground or on water.

[0058] The relative variation of the angle of attack and the position of the centre of thrust between the central wing 1 and the side wings 2 and 2' allows the selection of the distribution of the total lift between the side wings 2 and 2' and the central wing 1, these configurations being selected according to the different phases of flight.

[0059] At high relative aerodynamic angles of attack of the aircraft (> 10°), in particular for take-off and landing, the following configuration is adopted: the lateral wings 2 and 2' are pivoted to reduce the aerodynamic angle of attack of these wings in order to avoid stalling of the lateral wings 2 and 2' and to maintain the effectiveness of the roll control performed by the ailerons 5 and 5'. In this configuration, the central wing 1, which has a low elongation and is close to the shape of a delta wing, supports a larger part of the lift due to the vortices generated around it, while generating a stronger induced drag. The thus reduced lift-to-drag ratio is adapted to the landing phase.

[0060] In cruising flight, with the wings 2 and 2' fully extended (Ω = 0°), the three wings distribute the lift in such a way as to maximize the ratio of lift to drag, and the lift distribution is approximately in the form of an ellipse.

[0061] The lateral wings 2 and 2 ′ are each equipped with one or more rear control surfaces 5 and 5 ′, ensuring aerodynamic control of the aircraft 100 .

[0062] The aircraft 100 can also take off and land on the water due to at least two hydrofoils 6 and 6' being positioned below the central wing 1. The hydrofoils 6 and 6' can be retracted into corresponding housings 11 arranged in the central wing 1 (see arrow R). This can reduce the drag in flight and enable low-speed maneuvers in shallow water.

[0063] The central wing 1 comprises a cockpit 7 situated on the longitudinal axis X, close to the lateral wings 2 and 2 ′. This allows control of all the important elements of the aircraft 100 and of its spacing on the ground or on the water, making maneuvers in ports and airports easier.

[0064] The aircraft 100 is also provided with one or more pylons 8. Each pylon 8 supports a thermal or hybrid electric drive train 9. These pylons 8 are combined with rear control surfaces 10 for controlling the yaw and / or pitch and / or roll of the aircraft 100.

[0065] The rear part of the central wing 1 is equipped with one or more access doors 12, which can be opened upwards and or downwards. These doors 12 can be operated on the ground, in flight, on the water.

[0066] Finally, the central wing 1 is equipped with one or more emergency parachutes 13 distributed in a small volume.

[0067] It should be understood that the detailed description of the purpose of the present invention, which is given by way of illustration only, shall not be construed as limiting in any way and that technical equivalents are also included within the scope of the present invention.

Claims

1. An aircraft (100) comprising a main fuselage consisting of a central wing (1) for accommodating passengers and / or cargo, two side wings (2, 2') pivoting on the central wing (1) about respective axes of rotation (3; 3'), each wing (1; 2, 2') complying with the following geometrical characteristics: L arg is the distance between the two axes of rotation (3, 3') of the pivoting wing (2, 2'), L ong is the length of the central wing (1), H aut is the height of the central wing (1), E nv is the wingspan of the aircraft (100), Features: 0.3×L ong <L arg <L ong , 0.11×L ong <H aut <0.25×L ong , E nv >1.4×L ong ,and The rotation axes (3, 3') of the wing (2, 2') are inclined at an angle β relative to the vertical axis Z of the aircraft (100), so that the wing (2, 2') pivots from rear to front and vice versa to get closer to the fuselage or to deploy from the fuselage on both sides.

2. The aircraft (100) according to claim 1, characterized in that: The angle β satisfies the following condition: 10°<β<50°.

3. The aircraft (100) according to claim 1 or 2, characterized in that: The lateral wings (2, 2') each comprise at least a first aerodynamic control surface (5, 5').

4. The aircraft (100) according to claim 1 or 2, characterized in that: The wings (2, 2') pivot about their respective axes of rotation (3, 3') between a first extreme deployed flight position and a second extreme folded storage position of the aircraft, the magnitude of the angle Ω between these two extreme positions being approximately 70°.

5. The aircraft (100) according to claim 1 or 2, characterized in that: The wings (2, 2') pivot about their respective axes of rotation (3, 3') between a first extreme deployed flight position and a second deployed centered take-off and / or landing position, the magnitude of the angle Ω between these two positions being approximately 40°.

6. The aircraft (100) according to claim 1 or 2, characterized in that: The aircraft comprises at least one external pylon (8) above the central wing (1), supporting at least one electric and / or thermal propulsion device (9) and integrating at least a second aerodynamic control surface (10).

7. The aircraft (100) according to claim 1 or 2, characterized in that: The aircraft comprises at least two hydrofoils (6, 6') which are located below the central wing (1) and are retractable in the central wing (1).

8. The aircraft (100) according to claim 1 or 2, characterized in that: The aircraft comprises at least one door (12) at the rear and / or front of the central wing (1).

9. The aircraft (100) according to claim 1 or 2, characterized in that: The aircraft comprises at least one cockpit (7) on top of the central wing (1) and at the level of the side wings (2, 2').

10. The aircraft (100) according to claim 1 or 2, characterized in that: The aircraft comprises an emergency parachute (13) which is inside the central wing (1).

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