High-capacity, triple-hull, subsonic civil transport aircraft, compatible with a high-aspect-ratio tandem wing, and with optimizable lift-to-drag ratio.

Abstract

The invention describes a fuel-efficient subsonic aircraft with a tandem wing (7) with two very high aspect ratio wings, allowing both sufficient lift, a limited wingspan and favorable reception at airports, and three horizontally joined tubular fuselages (4), (5) and (6) with a common cabin, with the arrangement in which said two mid-wing fuselages (4) and (6) are, compared to said central fuselage (5), 50% shorter, which arrangement is part, at equal capacity, of a weight limitation strategy for said triple fuselage, said two mid-wing fuselages (4) and (6) being set back from said central fuselage (5), additional lift being able to be acquired also by the aerodynamic profile of the belly and back of said triple fuselage,The aircraft in question ultimately benefited from an optimized design (aerodynamics-capacity-weight-lift-size) to promote fuel efficiency and limit its propulsive power and wingspan requirements. Figure 9,

Description

Title of the invention: Subsonic civil transport aircraft with a tandem wing and a triple-hull fuselage

[0001]

[0002] STATE OF THE ART

[0003] Both to reduce the anthropogenic pressure on the planet, already denounced thirty-one years ago at the Rio Summit in 1992 with the presence of 110 Heads of State, and in the economic interest of airlines, transport aircraft must now consume as little fuel as possible, and this is imperative.

[0004] The sobriety of aircraft depends in particular on their finesse, which depends on the Lift / Drag ratio.

[0005] As the plane gains speed, it experiences an increase in both lift and drag.

[0006] The improvement in the Finesse of the aircraft is then based on an increase in Lift greater than the increase in Drag.

[0007] Lift and Lift / Drag Ratio can be improved when the wing has a NACA listed wing section profile and when the wings have a large aspect ratio and a large span.

[0008] Note that NACA wing profiles are aerodynamic profiles for aircraft wings developed by the National Advisory Committee for Aeronautics in the United States.

[0009] Unfortunately, the optimization of these profiles uses a reference cruising speed of Mach 0.85, whereas environmental wisdom, since the Rio summit in 1992, would have wanted transport aircraft to lower their cruising speed to Mach 0.7 to save fuel.

[0010] Quite the opposite happened. A few years after the Rio Summit in 1992, their optimal cruising speed increased from Mach 0.75 to Mach 0.85. This was and still is catastrophic for CO2 emissions. The opposite, a change from Mach 0.75 to Mach 0.7, would have saved enormous quantities of CO2 emissions into the atmosphere for thirty years.

[0011] It goes without saying that the present invention of a transport aircraft has taken care to consider compatibility with a cruising speed of Mach 0.7 by providing for the corollary use of a wing without a boom, as is the case of the joint Nasa-Boeing project called Aurora D8, and mentioned below.

[0012] Returning to lift, let us point out that it can also be improved when the wings have a weakly positive incidence.

[0013] The laws of aerodynamics and interactions (air flow-structure) give a limit to the lift obtained by the incidence of the wing.

[0014] An aerodynamically optimized profile has, firstly, the quality of delaying the loss of laminarity of the air flow at the leading edge to make way for a turbulent flow. Depending on the profile and the incidence, this turbulent flow can continue to preserve the attachment of the boundary layer. But at too high incidences of an already aerodynamically optimized profile, a detachment of the boundary layer takes place, in which both the quality of the turbulence created at the leading edge deteriorates (it tends to detach from the profile) and overpressures on the side of the trailing edge rise towards the leading edge. We then see turbulence which can no longer re-attach to the profile and a dissipation of its energy, which is unfavorable to the lift. Three effects promoting lift, the effect resulting from Bernoulli's Laws, the effect resulting from Newton's laws and the Coanda effect, are then no longer sufficient to carry the aircraft.

[0015] The example of multi-shell flying wings where the fuselage and the wing are fused shows that the geometry of the fuselage can also play a role in the lift. Cf Bishara, Majeed, Peter Horst, Hinesh Madhusoodanan, Martin Brod, Benedikt Daum, and Raimund Rolfes. 2018. "A Structural Design Concept for a Multi-Shell Blended Wing Body with Laminar Flow Control" Energies 11, no. 2: 383.

[0016] Multihull flying wings are trapped in a dilemma which is as follows:

[0017] either a significant part of the ends of their sails is characterized by a geometry of great elongation, and they take on a wingspan disproportionate to their capacity,

[0018] either no part of their wing has a high aspect ratio geometry, and their aerodynamic performance is penalized.

[0019] Finally, the acceptance of high-performance multi-hull flying wings in airports poses problems of space and bulk.

[0020] Alongside multihull projects, there are double-hull projects, i.e. with two fuselages joined together. Note that the number 2 is an even number, unsuitable for central symmetry which allows a central fuselage and side fuselages to be opposed. For example, two fuselages joined together cannot be opposed for a differential incidence, whereas it is possible for a central fuselage and two central fuselages, three in total, an odd number.

[0021] The joint double-hull project of NASA and Boeing, called Aurora D8, is based on two fuselages joined together, and is partly based on the idea that this so-called "double-bubble" or "double-hull" fuselage could contribute to both a gain in capacity and a gain in lift for the aircraft.

[0022] To our knowledge, NASA and Boeing specify how this gain in capacity is achieved, and would seem to note a gain in lift due to the fuselage, but do not specify how this gain in lift could be achieved.

[0023] Certainly, for the Aurora D8 project, NASA and Boeing observed in the wind tunnel the effects of incidences according to the geometries of the various shapes of the fuselage and its angles of attack.

[0024] An example of NASA study on the angle of attack of the fuselage nose of the Boeing D8 transport aircraft project studied in wind tunnel and numerical simulation is described. (See [Fig.24] and [Fig.25] page 27 of the document: Brian Yutko, Neil Titchener, Christopher Courtin, Michael Lieu, Larry Wirsing, David Hall, John Tylko, Jeffrey Chambers, Thomas Roberts, Clint Church. Aurora Flight Sciences, A Boeing Company. DESIGN AND DEVELOPMENT OF THE

[0025] D8 COMMERCIAL TRANSPORT CONCEPTIONS 2018, Belo Horizonte. Brazil.)

[0026] The general characteristics of the joint NASA-Boeing double-hull project, Aurora D8, are also discussed on page 13 of the document A1RCRAFT AND TECHNOLOGY CONCEPTS FOR AN N+3 SUBSONIC TRANSPORT, PHASE 2 FINAL REPORT. A. Uranga, M. Drela, EM Greitzer, C. Casses, DG DiOrio, AE Espitia, AD Grasch, DK Hall, AC Huang, MK Lieu, S. Sato, NM Siu, CS Tan, NA Titchener, E. van Dam, Massachusetts Institute of Technology, Cambridge, Massachusetts JS-Hollman, D. Kordonowy, RA Opperman, JT Chambers, BD Smith, E. Pliakas, A. Cardona, S. Giblin, DS Campbell Aurora Flight Sciences, Cambridge, Massachusetts - WK Lord, GL Suciu Pratt & Whitney, East Hartford, Connecticut.

[0027] In fact, communication and publications regarding the joint NASA-Boeing double-hull project, Aurora D8, are quite confusing.

[0028] It is difficult to distinguish the benefits of this double-hull aircraft which would come from turbojets participating in an active ingestion of boundary layer (Boundary Layer Ingestion in English), from those which would come from the Pi empennage and the trailing edge of a fuselage flattened or even widened at the tail, from those which would come from the benefit obtained by the use of composite materials, and from those which would come from the shape of the fuselage and its nose which would have a lift capacity. We believe we understand that only a relationship is made between the nose of the fuselage and the Pi empennage, and which concerns the pitching moment, but that the shape of the nose itself has little importance on the lift of the aircraft.

[0029] In all these studies, the numerical simulation is essentially based on the Euler and Navier-Stokes equations, and on the equations describing the Fluid-Structure interactions.

[0030] The state of the art of Computational Fluid Dynamics (CFD) studies of the fuselage's contribution to lift and drag has been described. When we talk about the fuselage, we mean all its parts: nose, tube, tail, karmans or fusion fairings between the fuselage and the wing, belly fairing for landing gear.

[0031] Said contribution of the fuselage to lift and drag has only been partially described.

[0032] However, reference may be made in particular to the publications:

[0033] - Fabrizio Nicolosi, Pierluigi Délia Vecchia, Danilo Ciliberti, Vincenzo Cusati. Fuselage aerodynamic prediction methods. Aerospace Science and Technology, volume 55, pages 332-343, 2016.

[0034] - SV Rouhani and A. Jahangirian. A Fast and Efficient Method for Multiobjective Aerodynamic Optimization of a Civil Aircraft Fuselage. Journal of Aerospace Engineering. Volume 35, Issue 6. 2022.

[0035] -Aircraft Conceptual Design Practices and Case Studies.cddcd by Ideen Sadrehaghighi. CFD Open Series. Patch 2.55.

[0036] It can be noted that the majority of work on Aerodynamics in Aeronautics takes relatively easily into account the interactions (air flow-component of the aircraft), component by component - nose, tube, tail, wing(s), fairings -, but characterizes with more difficulty the conflicts of mass, speed, quantity of movement, pressure, density and kinematic viscosity between the different turbulences of the different components of the aircraft.

[0037] This conflict between the different turbulences of different origins is further complicated by the

[0038] profile of the friction of the air flows on the walls of the different parts of the aircraft. However, it can be noted that the graphics microprocessors (GPU in English for Graphic Processor Unit) bring real progress in the capabilities of digital simulations.

[0039] Tests in different types of wind tunnel (continuous wind tunnel, cryogenic wind tunnel) are another way of understanding these turbulence conflicts and the results of their effects on Lift and Drag, and on the Lift / Drag ratio.

[0040] Both in numerical simulation and in the wind tunnel, these tests are carried out according to different geometry and flight conditions: altitude, Mach number, temperature, angle of attack, Reynolds number for an air flow over a more or less long component, etc.

[0041] The invention describes a triple-hull subsonic transport aircraft, equipped with three tubular fuselages (4), (5) and (6) joined horizontally and made integral. Said fuselage (5) is central. The two fuselages (4) and (6) are lateral, identical, shorter, more or less median longitudinally, have a specific nose architecture and a specific tail architecture, and provide capacity in width rather than in length. The capacity solution adopted in the invention does not necessarily result in an excessive wingspan as in flying wings, because it is compatible with a wing resting on the wings in tandem with two wings with very high aspect ratio, which is not the case with multihull flying wings.

[0042] It should be remembered that a wing resting on the wings in tandem makes it possible to increase the lift without increasing the wingspan, knowing that too large a wingspan poses space problems in airports, and that these space problems are insoluble in Civil Aviation Airports.

[0043] The invention therefore has a decisive advantage over multi-hull flying wings (Blended Wing Body Aircrafts in English) which, with capacities greater than 350 passengers, cannot be equipped with very large wings without taking on an excessive wingspan, incompatible with the traffic constraints in Civil Aviation airports.

[0044] Then, the invention also proposes to grant to said lateral fuselages (4) and (6) a specific relative fixed differential incidence, for example, in first approach, -1 degree, 0 degree, +1 degree, relative to said central fuselage (5), to be tested in the different types of wind tunnel or in numerical simulation, and according to different geometries and flight conditions (altitude, Mach Number, temperature, Reynolds Number) to try to improve the Lift / Drag ratio.

[0045] More precisely, according to the invention, a transport aircraft (1) comprises three aerodynamic tubular fuselages (4), (5) and (6), horizontally joined and integral, with a partially circular or elliptical section, and in certain places pseudo-rectangular, of which said fuselage (5) is central and of which two (4) and (6) are annexed, shorter, lateral, identical, more or less median longitudinally, and provide capacity, said fuselages (4), (5) and (6) being able to receive fairings (84) and (86), and each having an aerodynamic nose, symmetrical or asymmetrical, the diameter of which increases rapidly with the length, a central tube, and a tail the diameter of which decreases with the length.

[0046] The additional capacity provided by said lateral fuselages (4) and (6) in width rather than in length, which is compatible with a wing resting on two tandem wings with high aspect ratio, and therefore compatible with the span constraints in airports, can be used for one or other of the following functions:

[0047] - passenger transport,

[0048] - transport of luggage,

[0049] - transport of goods

[0050] - carbon fuel tank,

[0051] - hydrogen tank

[0052] - ammonia tank

[0053] - various equipment.

[0054] The text of this patent uses the following designations:

[0055] The aerodynamic noses of the three fuselages (4), (5) and (6) are respectively called (44), (45) and (46), identifiable by the tens number equal to 4.

[0056] The central tubes of the three fuselages (4), (5) and (6) are respectively called (54), (55) and (56), identifiable by the tens number equal to 5.

[0057] The tails of the three fuselages (4), (5) and (6) are respectively called (64), (65) and (66),

[0058] identifiable by the ten digit equal to 6.

[0059] The fuselage frames of the three fuselages (4), (5) and (6), partially circular or partially elliptical or flattened and pseudo-rectangular, are respectively called (74), (75) and (76), identifiable by the tens number equal to 7.

[0060] The fairings of the three fuselages (4), (5) and (6) are respectively called (84), (85) and (86), identifiable by the tens number equal to 8.

[0061] The aerodynamic profile planes connected to the two fuselages (4) and (6) are respectively called (94) and (96), identifiable by the tens number equal to 9.

[0062] The geometry of the three fuselages (4), (5) and (6) is ensured by adjusting the diameter, section and shape of said frames (74), (75) and (76).

[0063] The solidarity of the three fuselages (4), (5) and (6) is ensured frame by frame, a frame (75) being fixed - on its right and on its left - to two frames (74) and (76) by means of fixing elements (99). In addition, a skin (88) consolidates the whole and softens the aerodynamics of the aircraft of the invention.

[0064] .

[0065] According to the invention, said lateral fuselages (4) and (6) are shorter than said central fuselage (5) in order, conversely, to promote the penetration into the air of the central part of said transport aircraft (1), this arrangement recalling numerous fossil birds and pterosaurs considered to be efficient gliders.

[0066] According to one version of the invention, the relative length of said lateral fuselages (4) and (6) is limited to 50% of the length of said fuselage (5). Excessively large relative lengths of said fuselages could make the aircraft (1) of the invention too heavy, remembering that the weight is made up for by the power and the number of turbo-jets but that, on the contrary, limiting the number and the power of turbo-jets remains a relevant objective in terms of fuel consumption.

[0067] According to one version of the invention, the noses (44) and (64) of the two lateral fuselages (4) and (6) are shaped into a more or less oblique cone, that is to say a more or less off-center cone of revolution.

[0068] According to one version of the invention, the noses (44) and (64) of the two lateral fuselages (4) and (6) are shaped in the form of a more or less flattened and more or less deflected bevel. and off-center, a non-deflected, non-off-center bevel shape corresponding to the shape of a high-speed train (TGV) nose.

[0069] Correlatively, the frames (74) and (76) of the noses (44) and (46) of the corresponding lateral fuselages (4) and (6) are partially flattened and pseudorectangular.

[0070] The obliquely coned noses (44) and (46) of the side fuselages (4) and (6) may present an aerodynamic advantage.

[0071] The beveled noses (44) and (46) of the side fuselages (4) and (6) may have an advantage in terms of capacity.

[0072] According to one version of the invention, as a compromise solution, the bevels of the noses (44) and (46) of the side fuselages (4) and (6) are manufactured with pseudo-rectangular frames (74) and (76) which become increasingly wider from the front part.

[0073] According to one version of the invention, the tails (64) and (66) of the lateral fuselages (4) and (6) have a more or less oblique cone shape, that is to say a more or less off-center cone of revolution.

[0074] According to one version of the invention, the tails (64) and (66) of the lateral fuselages (4) and (6) have a beveled shape.

[0075] Correlatively, the frames (74) and (76) of the tails (64) and (66) of the corresponding lateral fuselages (4) and (6) are partially flattened and pseudorectangular.

[0076] As for the noses, the tails (64) and (66) in oblique cone can present an advantage in aerodynamics.

[0077] As for the noses, the beveled tails (64) and (66) can present an advantage in capacity.

[0078] According to one version of the invention, as a compromise solution, the bevels of the tails (64) and (66) of the lateral fuselages (4) and (6) are manufactured with pseudo-rectangular frames (74) and (76) which become increasingly narrower as they progress towards the rear.

[0079] According to one version of the invention, the anchors of the wings of said transport aircraft (1) are arranged on said central fuselage (5).

[0080] According to one version of the invention, the anchors of the wings of said transport aircraft (1) are arranged on said lateral fuselages (4) and (6).

[0081] According to one version of the invention, the turboprops and / or turbines coupled to unducted propellers / or turbojets are attached to said tail (65) of said central fuselage (5).

[0082] According to one version of the invention, the turboprops and / or turbines coupled to unducted propellers and / or turbojets are attached to said central tube (55) of said central fuselage (5).

[0083] According to one version of the invention, the turboprops and / or turbines coupled to unducted propellers and / or turbojets are attached to the wings of said aircraft (1) of the invention, either above or below them.

[0084] According to one version of the invention, the turboprops and / or turbines coupled to unducted propellers and / or turbojets are attached to the empennage.

[0085] According to one version of the invention, the transport aircraft 1) of the invention is equipped with a maximum of three turbojets, two under the wing in the low position, and possibly a third at the end of the tail in the central position, with, according to the State of the Art, an air intake in the high position and an ejection of the gases in the low position.

[0086] According to one version of the invention, the transport aircraft (1) comprises a central fuselage and four lateral fuselages, i.e. 5 fuselages, the number 5 being an odd number which makes it possible to contrast a central fuselage and lateral fuselages, in particular in terms of their differential fixed incidence.

[0087] According to the invention, to create an additional increase in lift and compensate for the increase in drag caused by the wetted surface of the two lateral fuselages (4) and (6), the transport aircraft 1) of the invention is provided with a wing composed of a large-span wing with very high aspect ratio.

[0088] According to the invention, to create an additional increase in lift and compensate for the increase in drag caused by the wetted surface of the two lateral fuselages (4) and (6), the transport aircraft 1) of the invention is provided with a wing structure composed of two tandem wings with very high aspect ratio, which represents a type of wing structure that is efficient in terms of aerodynamic drag while at the same time being compact in width.

[0089] According to the invention, with the aim of minimizing fuel consumption (kerosene, and / or hydrogen and / or ammonia) as much as possible by focusing on a cruising speed of only Mach 0.7, the transport aircraft (I) of the invention is equipped with a wing structure composed of two tandem wings with very high elongation and zero sweep.

[0090] According to the invention, with the aim of effectively separating the drags of said two very high aspect ratio wings, one of the two wings is in the forward position and above the three fuselages (4), (5), and (6), and the other further back and in a lower position with an anchoring at the level of said central fuselage (5) or said lateral fuselages (4) and (6). The low height of the rear wing nevertheless provides the possibility of placing turbojets below it.

[0091] According to the invention,

[0092] said lateral fuselages (4) and (6) have a specific slight fixed incidence, different or equal to that of said central fuselage (5), designated at zero incidence as a reference. For example, at the start of the investigation, -1 degree, 0 degree, +1 degree can be three fixed incidence values ​​to be tested for said lateral fuselages (4) and (6).

[0093] Larger angles of fixed differential incidence can then be considered, once the lessons learned from these three initial fixed differential incidences, which are low in absolute value, have been learned.

[0094] It should be noted that the turbulent air masses resulting from the penetration into the air of said lateral fuselages (4) and (6) come into conflict with the turbulent air masses resulting from the penetration into the air of said central fuselage (5), and the resultant of these effects can be neutral or positive or negative for the Lift / Drag ratio.

[0095] Indeed, said central fuselage (5) recalls, in Birds and Pterosaurs in full flight, the head-neck-central part of the body-tail-legs sequence,

[0096] while the said lateral fuselages (4) and (6) recall the lateral parts of the body of these creatures champions in the Art of gliding and in the Art of active flying.

[0097] More specifically, said central fuselage (5) recalls, in giant Pterosaurs in full flight, the giant head-neck-central part-body-tail-legs sequence, while said lateral fuselages (4) and (6) recall the lateral parts of the body. In this sequence, the body of the Pterosaur is in a more or less median position longitudinally. The angles in full flight of these different parts of the body are essential data in trying to understand how Pterosaurs acquire finesse of flight, knowing that knowledge on this subject is almost zero.

[0098] To be convinced of this, it is enough to consult the Wikipedia article "Flight of the Pterosaur" to see this, since the said article does not even address the gigantism of the head of these fossil animals. The American Museum of Natural History reasons differently, but the author of the present invention does not share its opinion.

[0099] According to the American Museum of Natural History, the giant skulls of Pteranodons are equipped with a bony crest and cartilaginous outgrowths, which is correct.

[0100] The American Museum of Natural History explains that its exact purpose is not yet known, but it is assumed that it could have served as a counterweight to the beak, or as a seductive attribute for mating, or even as a rudder in flight. It has also been suggested that males had longer crests, but this remains to be proven because the sex of fossilized animals is difficult to identify.

[0101] According to the author of the present invention, these hypotheses seem very fragile, because they move away from the striking characteristic of giant Pterosaurs: their capacity for flight and their capacity to support high wing loads.

[0102] It is certain that the gigantism of Cryodrakon boreas, Quetzalcoatlus northropi, Hatzegopteryx thambema, Arambourgiana philadelphiae, and in particular the gigantism of their heads, remains an enigma for the scientific community. However, the author of the invention proposes a more credible explanation.

[0103] While the American Museum of Natural History observes that, during Evolution, the increasingly notorious gigantism of Pteranodons and their wings were correlated with their wing-loading capacity, and were faithfully accompanied by the increase in the size of their skull, crest and neck, which just, The author of the present invention points out that nothing is known about the turbulent conflicts arising from both their giant head - including skull, crest and neck -, their body and their wings.

[0104] The author of the invention also points out that birds do not have this giant head, have in full flight a rectilinear alignment head-neck-central part of the body-tail-legs, and, at the same time, do not have the exceptional wing load capacities of the Pterosaurs. However, it is necessary to mention the angles (giant head-neck, giant head-body, neck-body), and these angles are, according to the author of the invention, the key to the biophysical enigma concerning the exceptional wing load capacity of the Pteranodons.

[0105] Indeed, the author of the invention prefers to consider that the giant heads of the Pteranodons are turbulators acting in synergy with the other turbulatory parts of this flying animal. The author of the invention proposes to create the word "Co-tubulator" to designate a component of the architecture of the aircraft whose role is to create turbulence which will come into conflict with the turbulence of the other components of said aircraft.

[0106] The author of the invention contrasts the observation of an isolated turbulence, originating from a single object, which is a dispersive phenomenon by nature, with the observation of several turbulences originating from several objects or from objects with specific geometries, which can converge and lead to much less dispersive phenomena, or even to reconvergences. Thus the use of a “Co-turbulator” aims to create an anti-dispersive effect of the turbulences capable of promoting the “Lift-Drag” ratio.

[0107] The author of the invention notes that on the margins of the present innovation, where we are looking for turbulence conflicts of different parts of an aircraft, and where we want to optimize their joint effects, the repercussions of the invention, besides its contribution to Civil Air Transport, will create a case of back and forth between "retro-bio-explanatory experimental physics" and its opposite, biomimicry, and we can hypothesize the role of the angles at which the Pterosaurs respectively maintained their giant head and their neck to obtain optimal finesse.

[0108] The main claim in the invention relates to a triple fuselage, including two shorter side fuselages, a solution offering compatibility with a tandem wing. The problem posed in the invention in subsidiary to the main claim, namely the result of a conflict of turbulences, is not classic in Aeronautics, at least to our knowledge. The present invention involves not only attempting to minimize turbulence and drag, which is classic, but also, which is not classic, once the turbulence has been reduced to a minimum, attempting to recover the energy of the different turbulences and seeing if the resultants of their dynamic conflicts can act to the benefit of the Lift / Drag ratio and the finesse of the aircraft.

[0109] In the invention, the search for the optimal differential fixed incidence of the lateral fuselages (4) and (6) is carried out in the different types of wind tunnel and in digital simulation (CFD) with GPU microprocessors.

[0110] Both methods, wind tunnel and digital simulation, can benefit from digital learning (Machine Learning in English), where the results of a wind tunnel or digital simulation experiment digitally shape the modalities of the next one.

[0111] According to one version of the invention, in order to fix Reynolds numbers (Re) for the tests aiming at the best fixed incidence and the best fixed differential incidence concerning the aircraft of the invention, the relative length of said lateral fuselages (4) and (6) is fixed at 50% of the length of said fuselage (5),

[0112] because the Reynolds number attributable to each fuselage takes into account the length of the wetted surface, taken parallel to the flow.

[0113] Indeed, the aerodynamic effect of said lateral fuselages (4) and (6) could be too insignificant for too short relative lengths. This reference of relative length to (50%) was already mentioned previously, but as maximum relative length and for reasons of weight. It was said there that excessively high relative lengths of said lateral fuselages (4) and (6), greater than 50%, could make the aircraft (1) of the invention too heavy.

[0114] At this stage, to move from the relative length (50%) of said lateral fuselages (4) and (6) to their absolute length, it is necessary to recall how the Reynolds number Re is calculated as a function of the flow length of the air flow.

[0115] The Reynolds number Re is equal to VL / u,

[0116] V average speed

[0117] L reference length of the flow

[0118] u kinematic viscosity of the fluid

[0119] In words, we have Re = ((average speed) x (reference length)) / (kinematic viscosity of the fluid).

[0120] According to the invention, two absolute lengths of the transport aircraft (1) of the invention are tested:

[0121] - 30 meters, a length which corresponds to the lower range of length of single-aisle aircraft on the market,

[0122] - 60 meters, a length which corresponds to the lower range of length of twin-aisle aircraft on the market.

[0123] The low length ranges are chosen because the transport aircraft (1) of the invention needs a shorter length to ensure the same capacity as the aircraft on the market.

[0124] At these lengths, the Reynolds numbers of Civil Aviation aircraft oscillate between 30 and 60 million at a speed more or less close to their cruising speed.

[0125] Consequently, the reference Reynolds numbers for the tests for said lateral fuselages (4) and (6), which will correspond respectively to lengths of 15 and 30 meters, will oscillate between 15 and 30 million.

[0126] In wind tunnel tests, if 1 / 18 scale models are used, Reynolds numbers are required for reference, which range between 1.87 and 3.3 million for said central fuselage (5), and between 1.87 and 0.83 million for said lateral fuselages (4) and (6).

[0127] These modifications could deviate from the real values, but the experimenters take care to make experimental corrections which are based on a modification of the pressure and temperature of the fluid.

[0128] Similarly, in order to trigger and observe in good similarity the detachment of the boundary layer, and according to the State of the Art of wind tunnels, the surfaces of the model of the aircraft have an artificial roughness, so that the flow is made as similar as possible to the real values.

[0129] According to one version of the invention, the best fixed differential incidence of said lateral fuselages (4) and (6) is of course determined by comparative tests in the different types of wind tunnel by tilting said lateral fuselages (4) and (6) more or less on the scale model of said transport aircraft (1).

[0130] According to one version of the invention, the best differential fixed incidence of said lateral fuselages (4) and (6) is of course determined by numerical simulations where the fixed angle of incidence of said lateral fuselages (4) and (6) is slightly varied, relative to that of said central fuselage (5).

[0131] According to one version of the invention, the nose (45) of the central fuselage (5) receives an additional component called here “co-turbulator” Pterosauroid (590), fixed or orientable in a vertical plane, which aims to create an anti-dispersive effect on turbulence, in particular that created by said lateral fuselages (4) and (6), said anti-dispersive effect being capable of influencing the value of the “Lift-Drag” ratio, an arrangement inspired by the giant head and neck of Pteranodons with high wing load capacity. FIGURES

[0132] [Fig.l] shows in profile view the central fuselage (5) with a nose (45), a central tube (55), and a tail (65), as well as said lateral fuselage (6) located on the right with a nose (46), a central tube (56), and a tail (66).

[0133] [Fig.2] represents in front view the noses (44), (45) and (46) respectively of the three fuselages (4), (5) and (6), and shows that the noses (44) and (46) of the two lateral fuselages (4) and (6) can be shaped, as in A, into a more or less oblique cone or, as in B, into a more or less flattened bevel.

[0134] [Fig. 3] shows a front view of a version of the transport aircraft (1) of the invention incorporating the nose versions (44) and (46) of the two lateral fuselages (4) and (6) in the shape of a more or less oblique cone or in the shape of a more or less flattened bevel.

[0135] [Fig.4] shows in front view, and for non-limiting examples:

[0136] in A: a transport aircraft (1) of the invention with a single wing anchored on the sides fuselages (5) and / or (4) and (6).

[0137] The motorization is based on two engines under the wing.

[0138] in B: a transport aircraft (1) of the invention with two wings in tandem anchored on the sides of the fuselages (5) and / or (4) and (6), one in the low position, the other in the high position.

[0139] The motorization is based on two engines under the wing.

[0140] in C: a transport aircraft (1) of the invention with two wings, one fixed above the fuselages (4, (5) and (6), and the other in a lower position.

[0141] The motorization is based on two engines under the wing.

[0142] in D: a transport aircraft (1) of the invention with two wings, configured as in C.

[0143] The engine is based on two turbojets under the wing, as well as two turboprops or two propfans in the rear position.

[0144] [Fig.5] shows the aircraft of the invention in top view. The capacity of the side fuselages (4) and (6) can be devoted:

[0145] in A, essentially to a cabin space, incidentally to tanks,

[0146] in B, half to a cabin space, half to tanks,

[0147] in C, incidentally to a cabin space, essentially to tanks,

[0148] [Fig.6] shows in perspective the three lateral fuselages (4), (5) and (6) of the invention, where the side fuselages (4) and (6) have beveled noses (44) and (46).

[0149] [Fig.7] repeats [Fig.6] with the additional representation of two fairings (84 and (86) located at the rear of the side fuselages (4) and (6).

[0150] [Fig.8] repeats [Fig.7] with the additional representation of a very large wing anchored on said lateral fuselages (4) and (6).

[0151] Two turbo-reactors are attached under the wing.

[0152] [Fig.9] repeats [Fig.7] with the addition of the representation of a small-span tandem wing, composed of two wings with very large aspect ratio,

[0153] one in the forward position and above the three fuselages (4), (5), and (6), and the other in a lower position with an anchoring at the level of said two fuselages (4) and (6), said wings having a zero or very weakly positive arrow; two turbojets are anchored under the rear wing in the low position.

[0154] [Fig. 10] repeats [Fig.9] with the addition of two turbo-propellers positioned at the tailplane level.

[0155] [Fig. 11] uses the tandem wing of Figures 9 and 10, but places two turbojets at the level of two lateral aerodynamic supports (94) and (96).

[0156] [Fig. 12] shows in section a superstructure (88) surrounding the three fuselages (4), (5), and (6), having the dual role of consolidating the joining of the three fuselages (4), (5) and (6) by means of the fixing elements (99), and of improving the aerodynamics of said transport aircraft (1) of the invention.

[0157] [Fig. 13] represents, in a bottom view and in perspective, a giant pterosaur. The invention invites us to consider them above all as coturbulators.

[0158] [Fig. 14] represents in perspective a giant pterosaur in full flight. The invention invites us to consider above all the angle that the giant head makes with the body to ensure its role as co-turbulator.

[0159] [Fig.15], like [Fig.14], represents in perspective a giant pterosaur in full flight. The invention invites us to also consider the angles (t,a), (t,c) and (a,c), to optimize the resultant of the turbulence conflict which depends in particular, according to the author of the invention, on the orientation of the co-turbulator (the giant head), and its respective angles with the neck and the body of the Pterosaur.

[0160] [Fig. 16] shows in profile the central fuselage (5) and the lateral fuselage (6) whose fixed incidence is aligned on the line a.

[0161] [Fig. 17] shows in profile the central fuselage (5) and the lateral fuselage (6) whose fixed incidence is aligned with the line b.

[0162] [Fig. 16] and [Fig. 17] are to be compared. The fixed incidence of the fuselage (6) is higher in [Fig. 17].

[0163] [Fig. 18] shows in profile the central fuselage (5) and the lateral fuselage (6) whose fixed incidence is aligned on the line a.

[0164] [Fig. 19] shows in profile the central fuselage (5) and the lateral fuselage (6) whose fixed incidence is aligned with the line b.

[0165] [Fig. 18] and [Fig. 19] are to be compared. The fixed incidence of the fuselage (6), different in [Fig. 19], can be obtained by the specific location of the fixing elements (99) between the frames (75) of the fuselage (5) and the frames (76) of the fuselage (6).

[0166] [Fig. 20] is identical to [Fig. 16]: it represents in profile the central fuselage (5) and the lateral fuselage (6) whose fixed incidence is aligned on the line a. But it also shows that the aircraft (1) of the invention can additionally include a pterosauroid co-turbulator (590) located on the nose of the central fuselage (5) and aligned on the line t.

[0167] [Fig. 21] is identical to [Fig. 17]: it represents in profile the central fuselage (5) and the lateral fuselage (6) whose fixed incidence is aligned with the line b. But it also shows that the aircraft (1) of the invention can additionally include a pterosauroid co-turbulator (590) located on the nose of the central fuselage (5) and aligned with the line t.

[0168] [Fig.22] shows a top view of the transport aircraft (1) of the invention, provided with a single wing, and with a central fuselage (5) whose nose is provided with a co-turbulator (590).

[0169] [Fig.23] shows a top view of the transport aircraft (1) of the invention, provided with two wings, and with a central fuselage (5) whose nose is provided with a co-turbulator (590).

[0170] [Fig.24] reproduces [Fig.22] of a transport aircraft (1) of the invention provided with a single wing and a co-turbulator (590), and compares its top view and that of a Pteranodon.

[0171] [Fig.25] reproduces [Fig.23] of a transport aircraft (1) of the invention provided with two wings and a co-turbulator (590), and compares its top view and that of a Pteranodon.

Claims

Claims

1. A low-energy subsonic civil transport aircraft with a tandem wing and a triple fuselage, characterized in that its structure combines a tandem wing (7) and a triple fuselage with three fuselages fused horizontally and with a cabin common to said three fuselages, namely a central fuselage (5), and two median lateral fuselages (4) and (6) shorter by 50%, the arrangement according to which said two median lateral fuselages (4) and (6) are shorter by 50% being part of a strategy for limiting the intrinsic weight of said triple fuselage, said aircraft ultimately benefiting from an optimized trade-off (capacity-total weight-lift-size) to promote its fuel efficiency and limit both its propulsive power and wingspan requirements.

2. A low-energy subsonic civil transport aircraft with a tandem wing and a triple fuselage, according to claim 1, characterized in that, to create an additional increase in lift and compensate for the increase in drag caused by the increase in wetted surface of the two lateral fuselages (4) and (6), said tandem wing (7) is composed of two wings with very high aspect ratio, which ultimately represents a type of wing that is efficient in terms of aerodynamic finesse while at the same time being compact in width.

3. A low-energy subsonic civil transport aircraft with a tandem wing and a triple fuselage, according to claims 1 and 2, characterized in that, with the aim of effectively separating the drags of said tandem wing (7), one of the two wings is in the forward position and above the three fuselages (4), (5), and (6), and the other further back and in a lower position with an anchorage at the level of said central fuselage (5) or said lateral fuselages (4) and (6),

4. A low-energy subsonic civil transport aircraft with a tandem wing and a triple fuselage, according to claim 3, characterized in that, with the aim of facilitating ground maintenance, two turbojets of limited diameter and therefore limited propulsive force are placed below the rear wing of said wing in tandem (7).

5. A low-energy subsonic civil transport aircraft with a tandem wing and a triple fuselage, according to claim 1, characterized in that additional lift is acquired not only by said tandem wing (7) but also by the belly and back aerodynamic profiles of said central fuselage (5) and side fuselages (4) and (6).

6. A low-pressure subsonic civil transport aircraft with a tandem wing and a triple fuselage, according to claim 1, characterized in that the noses (44) and (46) of said lateral fuselages (4) and (6) are shaped as a deflected cone.

7. A sober subsonic civil transport aircraft with a tandem wing and a triple fuselage, according to claim 1, characterized in that the noses (44) and (46) of said lateral fuselages (4) and (6) are shaped in a bevel.

8. A low-energy subsonic civil transport aircraft with a tandem wing and a triple fuselage, according to claim 1, characterized in that said lateral fuselages (4) and (6) have a fixed angle of attack, but slightly different from that of said central fuselage (5), either slightly higher or slightly lower, the choice of the angle of attack values ​​being fixed in the wind tunnel.

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