Aircraft equipped with a hybrid air propulsion system using propeller blades that are halted and folded at the end of the segment from takeoff to the top of the climb in level flight, and jet thrust propulsion during cruise flight

Abstract

The invention relates to an aircraft (10) equipped with a hybrid air propulsion system that uses propellers (40) configured to be decelerated, halted, and stowed at the end of a first flight phase, when a second phase of jet thrust propulsion during cruise flight starts. The propellers (40) are supported by nacelles (44) rotatably mounted on supports (45) integrally formed with lateral nose (12) and wing (16) surfaces and lateral tail surfaces (15) and are driven or halted by drive shafts (33) engaged with output shafts (31), respectively, powered by rotational energy sources or braked by propeller brake units, which may be housed in the nose (11), belly (13) and tail (14) of the aircraft (10). Collective pitch control mechanisms (50) and blade folding and unfolding mechanisms (60) are provided in the nacelles (44), which may comprise lateral steering mechanisms (70) configured to laterally direct the reverse thrust of the propellers (40) in order to maintain the alignment of the aircraft (10) on the runway during landings.

Description

AIRCRAFT PROVIDED WITH A HYBRID AIR PROPULSION SYSTEM BY PROPELLER BLADES THAT ARE PAUSED AND FOLDED AT THE END OF THE COURSE THAT GOES FROM TAKE-OFF TO THE TOP OF THE CLIMB IN LEVEL FLIGHT AND AIR JET THRUST IN CRUISE FLIGHT Field of invention

[0001] The invention relates to air propulsion systems and relates more particularly to an aircraft provided with a hybrid system that uses propeller blades configured to be slowed down, paused and folded at the end of a first phase of flight, when a second phase begins by air jet thrust in cruise flight. Fundamentals of the invention

[0002] Virtually all business jets and commercial aircraft, except regional turboprops, are powered by a type of jet engine known as a turbofan. This engine comprises a turbine engine extended along a longitudinal axis, also referred to as the main engine or core, which comprises a generally cylindrical casing in the form of an elongated fairing and is configured to drive a front fan mounted rotatably around the longitudinal axis. The engine core and front fan are housed in a generally cylindrical duct, also known as a nacelle, which, with the core spaced apart at the radial center, defines an annular channel intended to receive, in axial translation, a peripheral portion of the airflow accelerated by the front fan, which is referred to as secondary flow or bypass airflow.The main engine is supported by fixed structural components comprising a plurality of radial blades spaced circumferentially around a common axis, such as stator guide vanes integrated into the nacelle just aft of the front fan. The main engine fairing is configured to withstand conditions. extreme high temperature and high pressure and house in coaxial sequence, respectively, rotating fans of a low and high pressure compression section, a combustion chamber and rotating fans of a high and low pressure turbine section.

[0003] Thus, during a thrust phase, in which the internal mechanical assemblies of the main engine are driven into rotation, the air stream from the front fan accelerated into the nacelle separates into two annular coaxial flows parallel to the longitudinal axis: a radially inward flow through the main engine, also known as the primary flow or combustion air stream, which passes through the intake, compression, and combustion stages until it emerges explosively at high temperature and high pressure, driving the turbine section and generating jet thrust through an exhaust nozzle; and the secondary flow, radially outward, also known as the sheath flow, which runs parallel to the longitudinal axis between the guide vanes and around the core until it exits through an independent nozzle, providing the main thrust of cold air around the secondary thrust of hot gas stream expelled at high exhaust velocity.

[0004] Developed in the 1930s, widely used from the end of World War II until the mid-1960s, and still found in some military aircraft, turbojets, also known as turbine-driven airjet engines, were the first turbine engines for aircraft. Like turbofans, turbojets have a front-mounted fan that draws air through the nacelle inlet, but it does not separate it into hot and cold air streams as in turbofan engines. However, in both turbojets and turbofans, the air drawn by the engine in turbojets and by the core in turbofans undergoes the same intake, compression, and combustion stages, generating all or part of the thrust in turbojets.

[0005] While all the air ingested by a turbojet goes through the intake, compression, combustion and expulsion stages, a turbofan operates as a A turbojet that adds to the thrust of the combustion airflow the thrust generated by the cold air stream accelerated through a large peripheral area swept by the front fan, which is typically powered by the turbine section. This is particularly advantageous in the initial speed range, and especially during takeoff, phases of flight in which propulsive efficiency is directly proportional to the mass of the air stream and inversely proportional to its propulsive speed.In this sense, the fuel efficiency (defined as the mass of the aircraft divided by the power of its powertrain) provided by the advent of turbofan engines, in which large frontal fans are coupled to turbojet engines, can be seen as an empirical demonstration of the advantage of obtaining a large air mass combined with low kinetic energy, in a trade-off between the accelerated air mass and its propulsive velocity, which is achieved by increasing the disk area or propulsion area.

[0006] Just as the turbofan was invented to provide a larger thrust area and thus consume less fuel than the turbojet, another turbine engine was soon designed to accelerate even more cold air mass than the front-facing fans ducted in nacelles. Known as a turboprop, this engine comprises a coupled propeller that rotates in the open air to provide an even larger disc area than a turbofan system, meaning slower airflow for the same amount of thrust up to a certain flight speed.In other words, while the turbofan engine is more fuel-efficient than the turbojet due to its larger thrust area, turboprop systems, with their typically larger propellers than the ducted front fans, are more efficient at takeoff and in a first range of speeds, which is why, depending on the range of a regional flight, a modern turboprop aircraft can burn no more than two-thirds of the fuel per passenger compared to a state-of-the-art turbofan aircraft in the same maximum takeoff weight or payload category.

[0007] Developed during the 1940s, the turboprop engines that currently power the vast majority of regional aircraft are known for their reliability and fuel efficiency. However, despite the undeniable service provided by current turboprop and high-bypass turbofan systems, new turbine engines promise to surpass them in accelerating even more air mass at lower speeds than the air mass accelerated by previous systems. At least that's what their manufacturers, the British company Rolls-Royce and the French company Safran, intend to demonstrate with their new propulsion architectures, in terms of energy efficiency, within the framework of the European Union's public-private aeronautical research company Clean Aviation.

[0008] The first of two airjet engine-based aero-propulsion architectures under the aforementioned European research and innovation program concerns the Rolls-Royce turbofan known as UltraFan, which features a 3556 mm diameter front-mounted fan and a bypass ratio of approximately 15:1 to the combustion airflow mass passing through the core (bypass ratio). According to the UK engine manufacturer, its new engine will be installed in both narrow- and wide-body fuselages from 2030 onwards, will reduce fuel consumption by at least 25% compared to its predecessor, the Trent XWB series, and will also be the sustainable solution for decades to come.

[0009] French company Safran aims to reduce fuel consumption and greenhouse gas emissions from air travel by 20%. Known as a propfan, or open rotor engine because it lacks a large nacelle like that found in high-bypass turbofan systems, this type of engine generates most of its thrust through two rear-mounted, counter-rotating propeller modules, rather than the ducted fan of a turbofan or the single propeller of a turboprop. According to the French manufacturer, rotating the counter-rotating blades of the unducted coaxial fans in the open air significantly increases flow and thrust, thus reducing fuel consumption. and the environmental impact, since the proportion of air mass that passes around and through the core is much greater than that of today's most efficient turboprop engines.

[0010] Both the high-bypass turbofan and the propfan, while as promising as their manufacturers claim, are still relatively modest solutions compared with the advantages of an incomparably larger thrust area, or disc area, such as that provided by the hybrid air propulsion system of the character described.It is worth remembering that Rolls-Royce claims to have found the formula for accelerating a mass of cold air on the order of 15 times that of hot air, while the French engine promises a bypass of 30:1, probably due to the doubling obtained with the coaxial propellers, which obviously does not mean twice the net thrust of the Rolls-Royce propeller for several reasons, but also because, unless I am mistaken, the same two propellers of a propfan, if positioned without the intersection of their disc areas as in the system proposed by the invention, would be capable of providing more thrust than in the open rotor coaxial arrangement in which the two coaxial propellers in a row, or superimposed, act on a single propulsion area, and not two.

[0011] In contrast, next-generation electric or hybrid-electric aircraft have featured propulsion architectures with a large number of small propellers configured to operate from takeoff to landing, rather than opting for a few larger propellers to increase rotor area. Adequate for cruise flight but inefficient in an initial speed range, especially during takeoff, small propellers would obviously not be aircraft manufacturers' first choice if they could rely on a hybrid aircraft propulsion system that would free them, for example, from the challenging task of finding an efficiency compromise between the requirements of the different phases of flight.

[0012] It is known that low disk loads are the norm when it comes to turboprop aircraft, of which good examples are the twin-engine ATR 42-600 and ATR 72-600 manufactured by the Franco-Italian consortium ATR and the single-engine Swiss Pilatus PC-12, which operate with a disk load incomparably lower than that of a typical turbofan system, whose disk load, so high, is expressed in tons per square meter, sometimes exceeding 20 tons (Airbus A350), while the average of the three turboprop aircraft mentioned is 851 kg / m 2 . More specifically, the ATR 42-600, which of the three aircraft has the lowest disc loading and a maximum takeoff weight of 18.6 tonnes, is powered by a pair of 3930 mm diameter propellers, leading to a disc area of 24.26 m 2 and a disk load of 767 kg / m 2 , while in the 22.8 ton ATR 72-600 the disc load is 940 kg / m 2. The small Pilatus PC-12, with a maximum takeoff weight of 4,740 kg and a single propeller measuring 2,667 mm in diameter, operates with a disc area of 5.6 m 2 , which translates to a disk load of 846 kg / m 2 .

[0013] As will be appreciated in connection with the accompanying drawings, the aircraft chosen as an exemplary embodiment of the invention comprises a truss-wing fuselage compatible with Embraer's low-wing Phenom 100 model, whose maximum takeoff weight is approximately 4.8 tons. Considering that, on the one hand, the aircraft of this specification uses a single turbine engine, rather than two like the original Embraer, but that, on the other hand, its weight is added to that of batteries or high-energy-density devices, three electrical power units (herein understood as rotational power sources), three pairs of propellers and their respective transmission mechanisms, a maximum takeoff weight of approximately 6 tons can be expected. Furthermore, considering a diameter of 2667 mm for the steerable and folding propellers, the area swept by the three blades of each propeller will be 5.6 m 2 , with the three pairs making up a total disc or propulsion area of 33.6 m 2 .

[0014] It follows that an aircraft the size of an Embraer Phenom 100 or a Pilatus PC-12, once supplied with the hybrid air propulsion system of the nature described, you can benefit from the advantages of a remarkably low disk load, around 180 kg / m 2 , that is, less than a quarter of the lowest disk load of the three European turboprop aircraft discussed, that of the ATR 42-600 model, which is 767 kg / m 2 , which will lead to a proportional reduction in power requirements and a consequent improvement in flight parameters, in terms of safety, autonomy and energy efficiency, among other indicators, such as runway length and environmental and acoustic operational footprints of air transport.

[0015] While the specific embodiment of the proposed aircraft is considered in connection with such a 6-ton aircraft, clearly a large number of aircraft of varying capacities and sizes could benefit from the advantages of the invention's hybrid air propulsion system, which is configured to drive propeller blades during takeoff toward the end of a first speed range and then generate jet thrust during the high-speed phase of cruise flight. For example, a 50- or 70-seat regional turboprop aircraft with a maximum takeoff weight of between 20,000 and 25,000 kilograms, equipped with six approximately 4,000 mm diameter propellers configured according to the invention, would have a disk load of between 265 and 332 kg / m. 2, which clearly represents a major transformational leap, both from a quantitative and qualitative point of view, particularly in applications such as short-haul regional routes, which can translate into safer, faster and more economical travel, in addition to representing a significant step towards reducing the impact of aviation on the planet.

[0016] Despite the obvious benefits of the hybrid system proposed by the invention for small and medium-sized aircraft whose capacities and sizes are compatible with the turboprop systems discussed, narrow-body commercial aircraft equipped with two twin turbofan engines could also enjoy the advantages of the hybrid aircraft propulsion architecture of the nature described. Thus, assuming for hypothetical reasons that a narrow-body fuselage aircraft narrowbody of the current generation, such as an Airbus A220-100, which takes off with a maximum weight of 63,100 kg and a disc load of 1 1,738 kg / m 2, and that such a European aircraft is equipped with six steerable and folding propellers, for example 4600 mm in diameter, its total disk area will be approximately 100 m 2 and its disk load is of the order of 630 kg / m 2 .

[0017] For slightly larger aircraft, such as the twin-engine, narrow-body, six-abreast commercial aircraft Airbus A320 and Boeing 737, the invention's hybrid propulsion system is also of particular interest, since, as already mentioned, the disk loading of these turbofan aircraft is high enough to be expressed as at least ten and a half tons per square meter. Thus, considering an average weight of 75 tons for an Airbus A320 equipped with two twin CFM56 turbofan engines equipped with 1,730 mm diameter front fans, the total disk area is 4.7 m 2 and a disk load of 15,957 kg / m 2; while the Boeing 737, which can be enjoyed in an 85-ton Max model supplied with twin CFM International LEAP turbofan engines and 1760 mm diameter front fans, its disk area will be 4.86 m 2 , leading to a disk load of 17,490 kg / m 2 .

[0018] That is, for a hypothetical narrow-body commercial aircraft with six seats abreast and a maximum takeoff weight of around 80 tons, three pairs of 5000 mm diameter steerable and folding propellers will sweep an area of 19.63 m 2 each, providing a total swept area of 118 m 2 . Considering the maximum takeoff weight of 80 tons, its disk load will be 678 kg / m 2But that's not all. In addition to taking off and climbing in the first phase of flight with a smaller rotor area than today's best regional turboprops, a twin-engine aircraft configured this way will be capable of even more powerful takeoffs and climbs than those powered solely by its low rotor area of 678 kg / m 2 , since the residual thrust force of its turbofan engines is added to the propulsion provided by the blades of its pairs of steerable and folding propellers.

[0019] Regarding regional flights, the aforementioned Franco-Italian manufacturer ATR recently announced that it will soon launch a STOL (short takeoff and landing) variant of its ATR 42-600 model, the ATR 42-600S. This regional aircraft will be specially designed to take off from runways even shorter than the current 1,107 meters required for a conventional ATR 42-600. Although only for a 70% payload rating and missions no further than 200 nautical miles, according to ATR, its new regional route aircraft will be designed to take off from 800-meter runways and thus serve remote communities in more than a thousand locations, whose runways in demanding environments will be accessible to its 30- to 50-passenger STOL aircraft.

[0020] In addition to the attributes discussed and which will be appreciated in connection with the accompanying drawings, the aircraft proposed by the invention presents another advantage in terms of flight safety, not yet discussed. Once equipped with suitable electrical energy storage devices, the aircraft of the invention should take off without the jet propulsion unit (herein understood as the means for generating jet thrust parallel to the axis of symmetry) having to effectively cooperate. In other words, the electrical assemblies of such an alternative hybrid-electric modality will be sufficient for takeoff and climb to cruise level without or with little participation of the turbine engines.This means that the aircraft of the invention will not incur, for example, the proverbial risk of fauna, a common incident at airports worldwide involving birds and which is more serious when one or more birds are sucked into the engine, which can lead to the loss of power in one or both engines, as in the case known as the Hudson Miracle that occurred in New York in 2009, when an Airbus A320, even without power in both engines, managed to land on the Hudson River.

[0021] Despite the undeniable advances in the prior art, as well as the architectures announced by the European engine manufacturers mentioned above, the aircraft proposed by the invention will be able to provide much more efficient means of aerial propulsion, in terms of air traction and Energy efficiency, particularly during takeoff and climb, since the combination of the diameter and number of propellers of the hybrid system of the invention will be able to provide an incomparably larger disk area than those found in both the European engines discussed and in any other prior art. Furthermore, at higher speeds, the jet propulsion unit of the invention will also have the advantage of providing turbine thrust from a propeller that will be designed and calibrated exclusively for cruise flight. Thus, by combining the excellence of two propulsion modes, each dedicated to a specific phase of flight, the hybrid air propulsion system of the invention should increase overall efficiency, reducing pollution emissions throughout the entire operational envelope of an aircraft.

[0022] In practice, the energy efficiency of the aircraft described in the invention derives essentially from the versatility of the hybrid nature of its air propulsion system, which is capable of selectively operating with low disk load in the initial phase of flight and generating jet thrust during cruise flight. Given that the aircraft used here as an example of implementation is merely a preferred embodiment, it should be understood that, without deviating from the spirit of the invention, other configurations may be considered, such as aircraft with two or even just one pair of steerable and foldable propellers, which may or may not be driven exclusively by internal combustion engines, such as air-jet turbine engines.Furthermore, in embodiments with three pairs of steerable and folding propellers, the front pair may be powered by batteries or capacitors and a second intermediate pair by a generator, while the rear pair is driven into rotation by an engine or jet power unit located in the tail to also drive one or more generators, as already mentioned. Or the aircraft may have no batteries, with the front pair and at least one intermediate pair over the wing being powered by at least one generator driven by at least one internal combustion engine housed, for example, in the tail.

[0023] Because the invention's hybrid air propulsion system will be able to selectively provide a large disc area in those phases of flight where it is more advantageous to accelerate large air mass flows at low speeds than otherwise, this exceptional energy exchange in a first speed range will provide aircraft that are much quieter and more environmentally friendly than current ones. Furthermore, aircraft configured according to the invention should make a decisive contribution to air transport's goal of a sustainable and climate-neutral future, as well as significantly raise the safety standards of air travel, especially regional air travel, and the ability to decelerate efficiently in adverse conditions, such as wet or icy runways, as mentioned above, in addition to the ability to take off and land on shorter runways than those required by today's most efficient regional turboprop aircraft.

[0024] Since the invention's hybrid aircraft propulsion system will be capable of providing air thrust far beyond that achieved by the prior art, which, combined with new electrification technologies, should provide unprecedented starting power, speed recovery, and lift recovery, aircraft will have greater operational control, particularly in the phases of flight during which, as far as is known, most aviation accidents and incidents occur, especially in general aviation: takeoff / climb and approach / landing. Furthermore, an aircraft configured according to the invention offers the best conditions for aeronautical electrification to finally become a reality, since, depending on the configuration, electric motors will only be required for the phase from takeoff to the beginning of level flight, thus considerably reducing battery weight compared to a purely electric aircraft.Furthermore, taking into account the energy density of current batteries in the face of the range challenges of an aircraft, the invention's hybrid air propulsion system meets the best conditions for not compromising the minimum number of batteries. range, inconceivably poor foundation in the purely electric aircraft proposed so far. Brief description of the invention

[0025] Regarding the spatial orientation of the devices described, the terms vertical and horizontal refer to directions relative to the aircraft of the invention when in straight and level flight. Thus, "lateral" and "laterally" (as, for example, in "nose strut" and "directed laterally while operated") refer to directions that are angular to a central axis extending along a horizontal plane that includes the central axis, relative to which the horizontal plane extends to the left and right. The terms "upstream" and "downstream" refer both to the relative wind blowing in the direction opposite to flight and to the direction of internal circulation of the airflow of a turbine engine or the airflow from the blades of a propeller.

[0026] In an embodiment given purely by way of non-limiting example, an aircraft provided with the hybrid air propulsion system of the invention comprises a fuselage having a nose, a belly, a tail assembly and symmetrically coupled to the fuselage a wing and an empennage, at least one turbine engine and power assemblies intended to power propeller blades, which are configured to be slowed down, paused and folded or unfolded and restarted in flight, respectively, by propeller brake devices and blade folding and unfolding mechanisms, in addition to mechanisms for controlling the collective pitch of at least one pair of propellers.

[0027] According to such a non-limiting embodiment, a high wing is provided, which may be supported by rigid lateral struts, but may also be a cantilevered mid-wing. Furthermore, the empennage comprises a 'V' tail, and the turbine engine, which may be a turbofan, is provided on the axis of symmetry of the tail assembly.

[0028] The propeller is a pusher supported in an upstream casing or nacelle configured to house the collective pitch control and blade folding and unfolding mechanisms, the nacelle being supported by nacelle mounts in a rotatable manner about substantially vertical axes with respect to the aircraft positioning corresponding to straight and level flight.

[0029] The nacelle strut is a hollow cylinder substantially vertical, with respect to the positioning of the aircraft corresponding to straight and level flight, comprising an upwardly facing flange, each pair of nacelle struts being symmetrically integral with at least one of: distal ends of nose side surfaces symmetrically coupled to the nose, distal ends of tail side surfaces symmetrically coupled to the tail and wing assembly.

[0030] Alternatively, the nacelle supports of the nose side surfaces and tail side surfaces are supported on the distal ends of such side surfaces.

[0031] Alternatively, the nacelle is fixedly supported on at least one of: a pair of nose side surfaces, a pair of tail side surfaces, and a wing.

[0032] The nacelle is provided with fixed structural members configured to support at least two bearings, which operationally support a propeller drive shaft.

[0033] Alternatively, the drive shaft is operationally supported by at least one shaft bearing and at least one actuator bearing, which is supported by a linear actuator, the one or each shaft bearing being supported by a shaft support and the linear actuator by an actuator support.

[0034] Each nacelle support supports at least one bearing supporting a drive shaft meshed at one end with an output shaft supported by at least one bearing and at the other end with the driving shaft, which is configured to support a propeller hub comprising distributed around, in a substantially concentric and equidistant arrangement, pairs of hub lugs provided with pairs of bearings that rotatably support hub lug axes, each hub lug axis being perpendicular to the axis of symmetry of the respective blade, the root of which is integral with the corresponding hub lug axis, with which the blade is rotated about the bearings of the hub lugs to be folded or unfolded.

[0035] Alternatively, the hub shafts are integral with the hub lugs and provided with bearings configured to support the spur gears, which in this case are integral with the blade root lugs, the spur / bevel gears, lugs and gears therefore being configured to rotate about the hub shafts integral with the hub lugs.

[0036] Each propeller hub is provided with a conical fairing (spinner) positioned downstream, which comprises niches in which the blades are housed after being folded.

[0037] The collective pitch control mechanism comprises an interposed linear actuator, in the form of a hollow cylinder whose radially inner cylindrical surface projecting towards the propeller hub is referred to as the axially extended annular portion and comprises at its distal end a rotating ring coupled by rolling elements, the interposed linear actuator being coaxial but not in contact with the driving shaft and positioned between the propeller hub and the linear actuator of the blade folding and unfolding mechanism, the linear actuator, as a hollow cylinder coaxial with the driving shaft, is stationary relative to the nacelle and configured to pull or push axially, i.e. in a direction parallel to the driving shaft, with its hydraulic cylinders, the interposed linear actuator,whose rotating ring of the axially extended annular portion is integral with cylinders with toothed bars extended axially in the direction of the propeller hub and meshed with cylindrical gears integral with the hub shafts, in turn integral, with blade root handles, which when rotated about the hub axes by the cylindrical gears, when driven by the cylinders with toothed bars, rotate the blades to a folded or out-of-operation position, in which they are aligned lengthwise in the direction opposite to flight, or to an unfolded, operational or deployed position, in which their chords at zero pitch are coplanar with the plane of rotation of the propeller;while the collective pitch of the blades is adjusted whenever the interposed linear actuator is commanded with its hydraulic cylinders to axially pull or push a non-rotating ring coaxially coupled by rolling elements to a rotating ring integral with cylinders with toothed bars, which are extended axially towards the propeller hub and meshed with cylindrical portions of cylindrical / bevel gears integral with the hub shafts, the bevel portions of the cylindrical / bevel gears being meshed with blade bevel gears, integral with the blade roots and coupled to the blade root lugs by bearings around which the blades are rotated and around the lengthwise extended shafts themselves, changing the attachment angle relative to the propeller hub and adjusting the collective pitch.;

[0038] At least one power assembly and at least one braking device of at least one pair of propellers are housed in the nose, belly or tail assembly and connected to the respective drive shafts by drive paths passing both through nacelle struts and through at least one pair of nose side surfaces, wing side struts or tail side surfaces.

[0039] Alternatively, at least one braking device or at least one of each is housed in the nacelle.

[0040] When commanded to operate, a linear actuator of each propeller's lateral steering mechanism, which is supported by the nacelle and connected to a fulcrum on the nacelle mount, pulls or pushes the fulcrum causing the nacelle to rotate right and left around the substantially vertical axis of the nacelle support, with respect to the positioning of the aircraft corresponding to straight and level flight.

[0041] Alternatively, the linear actuator and fulcrum are supported inside the nacelle.

[0042] Upstream of a front fan ducted by a turbine engine nacelle, a mechanical transmission system comprises an output shaft powered by the front fan and engaged with a transmission shaft connected in turn to a pair of propellers, to an electric generator housed in the tail assembly, or to both, the output shaft and the transmission shaft being housed in a fairing stationary relative to the turbine engine nacelle, the fairing comprising an axially elongated conical portion configured to support the output shaft, both being coaxial with the front ducted fan, and a flattened cylindrical portion, which is aerodynamically tapered at the leading and trailing edges and extended in a direction perpendicular to the conical portion to support the transmission shaft.

[0043] Alternatively, the mechanical transmission system is positioned downstream of the turbine engine's front fan. Brief description of the drawings

[0044] For a better understanding of the invention and to show more clearly how it can be carried out, reference will now be made to the attached drawings, not necessarily to scale, in which similar parts and components are typically identified with similar reference characters in the different examples of embodiment revealed throughout the various views, of which:

[0045] FIG. 1 is a perspective view of an aircraft provided with the hybrid air propulsion system of the character described being driven by three pairs of steerable and folding pusher propellers;

[0046] FIG. 2 is a perspective view of a lateral support provided with a fairing or nacelle of the left front propeller of the aircraft of FIG. 1, the nacelle being illustrated in radial section to show mechanisms for controlling collective pitch, folding / unfolding, and lateral direction of blades;

[0047] FIGS. 3-4 are identical to FIG. 2, but illustrated without the side support to show a drive path between an output shaft and the driving shaft, respectively without and with shaft bearings;

[0048] FIG. 5 reproduces in a front view the same scene as FIG. 4;

[0049] FIG. 6 is a perspective view of a left-hand propeller provided on a wing, but illustrated without the wing to show a drive path through bearing-supported shafts;

[0050] FIG. 7 is a perspective view of the propeller, but illustrated without the side support and nacelle to show the mechanisms for controlling the collective pitch and folding of the blades;

[0051] FIG. 8 is a partially exploded perspective view of FIG. 7 but without the drive shaft to show mechanical actuator assemblies of the collective pitch and blade folding control mechanisms;

[0052] FIG. 9 is a perspective view of the same left front propeller as in the previous figures during a ground deceleration reversing the airflow 15 degrees to the left with respect to the aircraft's axis of symmetry;

[0053] FIG. 10 is a top view of the same aircraft as in FIG. 1 during a ground deceleration, with its three right-hand propellers reversing the airflow 15 degrees to the right and its three left propellers reversing the airflow 15 degrees to the left in relation to the aircraft's axis of symmetry;

[0054] FIGS. 11-12 are perspective views of a front fan of a turbine engine provided with a non-rotating cowling, which in FIG. 12 is seen in enlarged transparency comprising an output shaft meshed with a drive shaft;

[0055] FIG. 13 is a perspective view of the propeller proposed by the invention after it has been paused and folded, such as in a cruise flight, with the nacelle being illustrated in radial section; and

[0056] FIG. 14 is a top view of the aircraft of the invention, with its six propellers after being stopped and folded in cruise flight. Description of the invention

[0057] The aforementioned objectives and the means and methods for achieving them will be described below in sufficient detail to permit those of ordinary skill in the art to practice the invention. Before discussing them in detail, however, it should be understood that the invention is not limited to the specific constituent parts of the devices described, as such devices may vary. It should also be understood that the terminology used herein describes exemplary embodiments but is not limited to such particular embodiments. Furthermore, it is fully recognized that the various components of the aeromechanical configurations discussed may be employed separately or in any suitable combination to produce the desired results. Consequently, the examples of how the invention may be implemented are not individual arrangements related only to each other, but may also be taken in conjunction with other arrangements.Thus, if a specific characteristic is not covered in a first modality, but is recognized in a second, the technician in the subject will understand that this is not the case. necessarily means that such a characteristic cannot be included in said first modality, as he understands that the essence of this application is to report the mentioned characteristic for any modality and that this was not done just for the sake of clarity, and also to keep the descriptive report in a manageable volume.

[0058] Of primary interest in connection with this patent application is the disclosure of a hybrid aircraft propulsion system in which folding blades, preferably supplied in pairs, accelerate large axial flows of air mass at low speeds in a first stage of an aircraft's self-propelled flight, which begins during taxiing and continues into cruise flight, when the blades are paused and folded, with the remainder of the flight being powered by one or more air-jet turbine engines. Furthermore, an object of the invention is to disclose propellers configured to be steered laterally during operation, being rotated about substantially vertical axes in order to control the reverse thrust vector during landings, in which case the thrust is deflected a few degrees to the sides or toward the center toward the aircraft's axis of symmetry.With such deflection of the propellers, it is expected that the aircraft proposed by the invention will land perfectly centered on the respective landing strips, even in adverse conditions, such as a wet runway, covered in snow or crosswinds.

[0059] These and other advantages, aspects and characteristics of the invention will become more evident from the description of preferred operational configurations, given exclusively as examples of embodiment and not restrictive or limiting in any respect and which will be appreciated in connection with the attached drawings and the claims that accompany them.

[0060] Referring now more specifically to FIG. 1, the reference numeral 10 indicates an example of an aircraft configured in accordance with the invention, the fuselage of which comprises symmetrically coupled thereto a wing 16 and a tail assembly, generally indicated by the reference numeral 14, for the purpose of supporting and controlling the aircraft 10 in flight. In the specific embodiment illustrated, three pairs of steerable and foldable, hereinafter simply referred to as, propellers 40, driven in rotation by electric power units (not shown) and a turbine engine 20 provide effective reaction thrusts to propel the aircraft 10 forward into flight in the well-known manner.

[0061] Symmetrically coupled to the nose 11 of aircraft 10 in a dihedral configuration, that is, angled upward in the wingspan with the tips higher than the roots, are two twin nose lateral surfaces 12, similar to the flight control lateral surfaces known as canard wings, which can be seen on the sides of the nose of so-called three-surface aircraft, which, like the Italian twin-engine Piaggio P180 Avanti, comprise a nose plane, a central wing, and a tail plane, hence the reference to three surfaces. The nose lateral surfaces 12 of the invention, however, are not intended to control flight like canard wings, but merely to support a forward pair of propellers 40, while a middle pair, as seen in FIG.1, is symmetrically supported on wing 16 and a third pair on tail side surfaces 15, also dihedral and symmetrically coupled to tail assembly 14, but positioned above the level line of their nose counterparts.

[0062] As already mentioned, in the hybrid aircraft propulsion system configured according to the invention, powertrains drive blades 41 of propellers 40, and at least one turbine engine, such as turbine engine 20, provides jet thrust according to the aircraft's flight phase. Although aircraft 10 is a hybrid configuration comprising three pairs of propellers 40 and a single turbine engine 20, it should be noted that, without departing from the spirit of the invention, other powerplant combinations could be provided, such as arrangements with two pairs of propellers, a pair of turbofan engines, or even a single pair of propellers. Furthermore, instead of three-bladed propellers, propellers provided with different numbers of blades may be employed and yet such embodiments still fall within the scope of the claims.

[0063] Likewise, without departing from the spirit of the invention, an aircraft may be configured with an aerial propulsion system that is hybrid only in the sense of using propellers in a first range of speeds and jet propulsion in the second phase of flight, but not in the sense of using electric motors and batteries combined with internal combustion engines, as in aircraft 10. For example, an aircraft may be configured without electrification and still be in accordance with the invention by using in the tail assembly two twin turbine engines intended to drive in rotation only a pair of tail side surface propellers, which would be configured to be paused and folded exactly as occurs with the propellers 40 of the invention and which in the exemplary embodiment of aircraft 10 may be powered by both a set of electric motors and the turbine engine 20.

[0064] Revisiting FIG. 1, in which aircraft 10 is propelled in flight by blades 41 of propellers 40, an electric power unit (not shown) housed in nose 11 rotates output shafts 31 (FIG. 3) housed in nose side surfaces 12 to drive in rotation the forward pair of propellers 40. Provided upon wing 16 assisted by a pair of twin side struts 16a, the middle propellers 40 are driven in rotation by output shafts 31 powered by an electric power unit (not shown) housed in a belly 13 of aircraft 10. The output shaft 31 of left middle propeller 40 is illustrated in FIG. 6, which to better depict a drive path does not show wing 16 nor the corresponding left side strut 16a. The rear pair of propellers 40 is powered by the turbine engine 20 provided on the axis of symmetry of the tail assembly 14 between inclined stabilizers or empennage 14a. FIG.1 also shows in front of the turbine engine 20 a fairing 23, which houses an output shaft 21 engaged with a transmission shaft 22 (FIG. 12) intended for only. drive in rotation, via transmission shafts 33 housed in the tail side surfaces 15, the rear propellers 40 or also power one or more electric generators (not shown) housed in the tail assembly 14.

[0065] FIG. 2 is a radial sectional perspective view of a nacelle 44 of the left front propeller 40, which is viewed with a drive shaft 43 operatively supported by a shaft support 43c and an actuator support 61c. The nacelle 44 may be defined as a shell or fairing configured with good aerodynamic properties and pivotally supported on a nacelle support 45, which is shaped as a hollow cylinder comprising a flange 45a and is integral with the nose side surface 12, the tail side surface 15, or the wing 16 as seen in radial section in FIG. 6, where, as already noted, for clarity the wing 16 is not illustrated.The nacelle 44 supports the propeller 40 and operational control mechanisms, both those of the propeller 40 itself and those of its blades 41, and is provided with a tubular hub fairing 44c, also illustrated in radial section as the nacelle 44 and configured to be slid on runners by an actuator (not shown) until it meets a conical propeller fairing 46 or spinner to cover a propeller hub 42, whenever the blades 41 are folded into respective blade niches 46a of the conical propeller fairing 46 during the transition to cruise flight.

[0066] The propeller hub 42 may be defined as a rotating chassis or load support, which is provided with a perpendicular hole in the center intended for the driving shaft 43 and three pairs of hub lugs 42a around it, each pair of hub lugs 42a being provided with a hub lug shaft 42c supported by a pair of bearings (not shown), in a substantially equilateral arrangement (FIG. 5). As for the side surfaces, both the nose side surface 12 and its tail counterpart, they are nothing more than load supports in the general form of an elongated plank with aerodynamically tapered leading and trailing edges along its length, the elongated plank having a dihedral portion and a distal portion, or proximal if in relation to the nacelle 44, which is extended in a substantially horizontal direction in the spanwise direction and measures approximately one-fifth of the length of the dihedral or non-horizontal portion (FIGS. 1 and 9).

[0067] The nacelle support 45 supports a press-fit bearing 44b to support an integral annular support 44a, which is integral with the nacelle 44. A fulcrum 45c for a linear actuator 71 of a lateral steering mechanism 70 of the propeller 40 is seen in FIG. 2, as is a bevel gear meshed with the single gear of the drive shaft 43. The propeller hub 42 is supported and driven by the drive shaft 43, in turn cantilevered by three bearings, a first bearing 43b of the shaft support 43c and a pair of bearings 61b (only one bearing 61b is shown) of a hollow cylindrical linear actuator 61, which is supported by the actuator support 61c (FIGS. 2 and 6). FIG.2 also reveals two pairs of side flaps illustrated in cross-section, by which the shaft support 43c and the actuator support 61c are integrated into the nacelle 44, as well as a collective pitch control mechanism 50 and a blade folding and unfolding mechanism 60 of the propeller 40, which will be discussed shortly, are also revealed.

[0068] FIG. 3 comprises the same components as FIG. 2 except for the nose side surface 12, the lateral steering mechanism 70, and the bearing 44b. Furthermore, the nacelle support 45 is not illustrated in its entirety, but in radial section. In FIG. 4, the same mechanical assemblies as in FIG. 3 are augmented by a bearing 31b of the output shaft 31 and four bearings 33b of the two drive shafts 33, while an intermediate gear 32 is illustrated without a bearing. The purpose of FIG. 3 by showing the output and transmission shafts without bearings is to show more clearly a drive path in connection with the driving shaft 43. The figure also illustrates, in whole or in part, the three blades 41, the propeller hub 42, the conical propeller fairing 46 and, on the left, one of the three blade niches 46a, while the radial sections of the nacelle 44 and the integrated annular support 44a integrated therein allow to appreciate, also in radial section, the nacelle support 45, which has the shape of a hollow cylinder whose lower edge is integral with the nose side surface 12 (not shown) and whose upper edge comprises the flange 45a, as already explained. Powered by a nose electric power unit (not shown) and connected to a propeller brake system 40, the output shafts 31 transmit rotational energy or decelerate, through the intermediate gears 32, the transmission shafts 33, which, in turn, rotate or decelerate the driving shafts 43.

[0069] The front view in FIG. 5 illustrates the same left front propeller 40 as in the previous three figures. The radial section of the integral annular support 44a, which is integral with the nacelle 44, is coplanar with the other cross-sections in the figure, including the radial section of the nacelle support 45, which comprises the flange 45a seen above the bearing 44b and the cross-section of the nose side surface 12, i.e., all sections in FIG. 5 are coplanar. With its non-rotating inner ring supported by the nacelle support 45 and rotating outer ring press-fit to the integral annular support 44a seen just below the flange 45a, the bearing 44b holds the nacelle 44, which can then be rotated about a substantially vertical axis by the linear actuator 71 of the lateral steering mechanism 70 of the propeller 40 (FIG. 2). FIG. 5 further illustrates the same drive path shown with bearings in perspective in FIG. 4, where nacelle 44 is seen without bearing 44b.

[0070] FIG. 6 is a perspective view of the left intermediate propeller 40 provided on the wing 16 (not shown), with its blades 41 extended in operational mode or deployed. Like the drive path illustrated in FIGS. 4-5 discussed, that of the intermediate propellers 40 comprises the output shaft 31 and two drive shafts 33 provided with respective bearings 31 b and bearings 33 b. However, an idler gear like that found in FIGS. 3-5 is not required for the intermediate propellers 40. Furthermore, the output shafts 31 provided within the pair of twin side struts 16 a (not shown) of the wing 16 are driven in rotation by an electric power unit (not shown) housed in the belly 13. Furthermore, the intermediate propellers 40 are identical to their front and rear counterparts and so will not be discussed in detail.

[0071] FIG. 7 is a perspective view of the propeller 40 with its blades 41 extended in the operational or deployed position, wherein are illustrated the drive shaft 43 provided with the collective pitch control mechanism 50 and the blade folding and unfolding mechanism 60, the propeller hub 42 provided with the three blades 41, and the conical propeller fairing 46 with its blade recesses 46a. From right to left, supported on the drive shaft 43 is the bearing pair 61b (only one bearing is shown) of the linear actuator 61 with its three hydraulic cylinders 61a. Further to the left, integral with the hydraulic cylinders 61a is an interposed hollow cylindrical linear actuator 51, which as seen in the image is concentric but not in contact with the drive shaft 43.The interposed linear actuator 51 is provided with three hydraulic cylinders 51 integral with a non-rotating ring 52, which with a rotating ring 53 composes a coupling, such as a swash plate of a helicopter rotor, in which a non-rotating ring transmits linear motion to a rotating ring through rolling elements. Or, in other words, the non-rotating ring 52 and the rotating ring 53 are the interface of an installation comprising the collective pitch control mechanism 50 and the blade folding and unfolding mechanism 60, which are mounted coaxially around the driving shaft 43, having on one side a non-rotating mechanical assembly, provided with the two linear actuators and the non-rotating ring 52 and, on the other side, a rotating mechanical assembly comprising the rotating ring 53, a rotating ring 54, cylinders with toothed bar 55, cylindrical / bevel gears 56, cylinders with toothed bar 65 and cylindrical gears 66.

[0072] In a partially exploded view, FIG. 8 reproduces the same mechanical assemblies as in FIG. 7, except for the drive shaft 43, the bearing 61 b and the linear actuator 61, which are only partially illustrated. As the exploded view allows to observe, an axially extended tubular portion 51 c is nothing more than a longitudinal prolongation of a radially internal cylindrical surface of the interposed linear actuator 51, which is projected axially towards the propeller hub 42 and comprises at its distal end a non-rotating raceway 51 d of rolling elements, such as the inner ring of a bearing. The partially exploded view further shows a plurality of rolling elements arranged in a circle, which, as in an outer race of a bearing, are provided in the rotating ring 54.

[0073] On the left in FIGS. 7-8, facing upward, is one of three blade wells 46a, which, as noted, are configured to house blades 41 when paused and folded during transition to cruise flight. The conical propeller fairing 46 is supported by the propeller hub 42, which is provided with the drive shaft 43 at its center and the three pairs of hub lugs 42a distributed around it in a substantially equilateral arrangement, as noted above. Each pair of hub lugs 42a is provided with the hub lug shaft 42c pivotally supported by a pair of bearings provided in the pair of hub lugs 42a (not shown). The hub lug shaft 42c of the hub lugs 42a may either be supported by the bearings (not shown) of the pair of hub lugs 42a, be provided bearingless, or be integral with the hub lugs 42a and therefore configured not to rotate relative to the hub lugs 42a on which they are supported.Obviously, in such an alternative embodiment the components supported by the hub lug shaft 42c would be supported in bearings to rotate about the hub lug shaft 42c. Furthermore, in such an alternative embodiment the spur gear 66 must be integral with a blade root lug 41a.

[0074] In the specific embodiment of aircraft 10, however, it was chosen to have the hub lug shaft 42c supported in bearings (not shown) provided in the hub lugs 42a, the hub lug shaft 42c therefore being rotatable, i.e., not integral in a single piece with each pair of hub lugs 42a. Revisiting FIGS. 7-8, more specifically the upper third of the propeller hub 42, which can be appreciated in connection with FIG. 5, from left to right, between the hub lugs 42a, integral with the hub lug shaft 42c is the spur gear 66 meshed with the toothed bar of the toothed bar cylinder 65, which is driven in linear motions to control the folding operation of blade 41. To the right of spur gear 66, also integral with hub loop shaft 42c, is blade root loop 41a coupled to a blade bevel gear 41c by a bearing (not shown). Thus, blade bevel gear 41c is rotatable relative to blade root loop 41a, but is fixed, or integral with blade 41, since its function is to adjust the collective pitch of blades 41 by changing their attachment angle relative to propeller hub 42 by rotating them about their own axis extended in the longitudinal direction. Meshed with blade bevel gear 41c is a bevel portion of spur / bevel gear 56, which is nothing more than a gear wheel obtained by the one-piece integration of a bevel gear with a spur gear.Just as the blade bevel gear 41 c rotates supported on the blade root loop 41 a by a bearing (not shown), the spur / bevel gear 56 rotates supported on the hub loop shaft 42 c supported on bearings (not shown). The toothed bar of the toothed bar cylinder 55 of the collective pitch control mechanism 50 is seen in mesh with the cylindrical portion of the spur / bevel gear 56, which with its bevel portion rotates the blade bevel gear 41 c of the blade 41 .

[0075] As already explained, the rotary ring 54 is rotatably supported by the rolling elements of the non-rotating raceway 51 d provided at the distal end of the axially extended tubular portion 51 c, which projects toward the propeller hub 42. Pierced by three equidistant holes parallel to the driving shaft 43, the rotary ring 54 is integral with the three bar-toothed cylinders 65, which are meshed with respective cylindrical gears 66. The three holes of the rotary ring 54 are traversed without contact by the three cylinders of the bar-toothed cylinders 55, which are integral with the rotary ring 53 and meshed with the cylindrical portions of the three cylindrical / bevel gears 56. That is, the three bar-toothed cylinders 55 operate inserted in the three ducts of the rotary ring 54 without contact with the edges of such ducts. As seen in FIG. 7, the shaft The driving shaft 43 is supported by the linear actuator 61, whose hydraulic cylinders 61 a are integral with the interposed linear actuator 51, which, as already mentioned, is coaxial with, but does not have contact with, the driving shaft 43. As already mentioned, the hydraulic cylinders 51 a of the interposed linear actuator 51 are integral with the non-rotating ring 52, which is coupled by rolling elements to the rotating ring 53, in turn integral with the three toothed bar cylinders 55, which are meshed with the cylindrical portions of the cylindrical / bevel gears 56, as already mentioned.

[0076] Bending of blades 41 is an operation triggered whenever a controller (not shown) actuates linear actuator 61, which can occur in two ways: bending only or bending and adjusting the collective pitch during bending. Bending without adjusting the collective pitch begins whenever the three hydraulic cylinders 61 a of linear actuator 61 pull the interposed linear actuator 51—without the three hydraulic cylinders 51 a of interposed linear actuator 51 doing the same with the non-rotating ring 52. That is, by pulling the interposed linear actuator 51 and its associated mechanical assemblies, linear actuator 61 simultaneously pulls the six toothed bars, both those of the toothed bar cylinders 55 and those of the toothed bar cylinders 65, which rotate the spur / bevel gears 56 and the spur gears 66.Since the bevel portion of the spur / bevel gear 56 is identical to the blade bevel gear 41c, when the latter is rotated about the hub lug axis 42c by 1 / 4 of a turn (equivalent to folding the blade 41), the spur / bevel gear 56 follows it in the rotation as it is also rotated 1 / 4 of a turn about its own axis. Since the bevel portions of the spur / bevel gears 56 and the blade bevel gears 41c have equal diameters (and the intervening linear actuator 51 has not been actuated), the collective pitch remains the same during a folding or unfolding operation of the blades 41, if that is the intention.

[0077] As for the adjustment of the collective pitch, this, as already mentioned, can be carried out independently of the folding and unfolding operations of the blades 41, which occurs, as is evident, whenever said controller activates the interposed linear actuator 51, which with its three hydraulic cylinders 51 a moves in linear motion the mechanical assemblies associated with them, causing the three cylinders with toothed bar 55 to rotate the three cylindrical / bevel gears 56, which drive the three blade bevel gears 41 c, thus changing the fixing angle of the blades 41 in relation to the propeller hub 42 to adjust the collective pitch of the blades 41 of each propeller 40.

[0078] The left front propeller 40 is seen after being rotated 15 degrees to the left about the nacelle support 45 in the perspective view of FIG. 9, in which the nacelle 44 and its tubular hub fairing 44c are illustrated in radial section. Since the fulcrum 45c is a fixed base on the flange 45a of the nacelle support 45, when commanded to be actuated, it is the linear actuator 71 that moves to rotate the nacelle 44 about the bearing 44b supported by the nacelle support 45, and not the fulcrum 45c, which is fixed. Thus, when the fulcrum 45c is pushed by the hydraulic cylinder of the linear actuator 71 as seen in the figure, the reverse flow of the left front propeller 40 is directed to the left.

[0079] FIG. 10 is a top view of aircraft 10 during a landing, in which the three right-hand propellers 40 reverse flow 15 degrees to the right and the three left-hand propellers 40 reverse flow 15 degrees to the left.

[0080] The turbine engine 20 is illustrated in perspective in FIGS. 11-12 comprising a fan ducted through a nacelle, the fan being supplied concentrically to an air inlet opening of the nacelle. In transparency in FIG. 12, mounted symmetrically forward of the front fan is the fairing 23, which houses the output shaft 21, a bevel gear 21c, the drive shaft 22, and a bevel gear 22c. The fairing 23 of the output shaft 21 and drive shaft 22 comprises a longitudinally elongated conical portion, coaxially upstream of the front fan, comprising an aerodynamically tapered cylindrical vertical portion, which connects the conical portion with an inner bottom surface of the nacelle air inlet. The transparency An enlarged view of FIG. 12 allows us to observe that the fairing 23 is provided with an output shaft support 21 a, in the form of a crosshead provided with a bearing (not shown) intended to support the output shaft 21, whose bevel gear 21 c is meshed with the bevel gear 22 c of the substantially vertical transmission shaft 22 supported on a bearing 22 b.

[0081] As already discussed, during the transition to cruise flight, after the blades 41 have been folded and housed in the respective blade niches 46a of the conical propeller fairing 46, the tubular hub fairing 44c is slid on slides (not shown) by an actuator (not shown) until the operating space of the propeller 40 closes around the already non-operating propeller hub 42. FIG. 13 is a perspective view in which the nacelle 44, the tubular hub fairing 44c, and the actuator support 61c are illustrated in radial section, with the blades 41 housed in the respective blade niches 46a of the conical propeller fairing 46. The image shows the interposed linear actuator 51 after being pulled by the linear actuator 61. As already explained, when pulling the interposed linear actuator 51, the linear actuator 61 also moves, and all at once, the mechanical assemblies associated with the interposed linear actuator 51.That is, the linear motion parallel to the driving axis 43 with which the linear actuator 61 pulls the interposed linear actuator 51 displaces intermediate cylinders and rings connected with the bar gear cylinders 55 and bar gear cylinders 65, of which the three bar gear cylinders 65 of a propeller 40 rotate in % of the cylindrical gears 66 around the three hub lug axes 42c to bend the blades 41.

[0082] FIG. 14 is a top view of aircraft 10 with blades 41 of three pairs of propellers 40 after they have been folded back by linear actuators 61 of blade folding and unfolding mechanisms 60 and housed in respective blade niches 46a, which are provided in conical propeller fairings 46. In the illustrated condition, aircraft 10 is powered in cruise flight by turbine engine 20, with the operating spaces of blades 41 around propeller hubs 42 covered by tubular hub fairings 44c.

Claims

MODIFIED CLAIMS Received by the International Secretariat on the 1st o July 2025 (01.07.2025) 1. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the travel from takeoff to the top of the climb in level flight and by air jet thrust in cruise flight, which comprises a fuselage having a nose (11), a belly (13), a tail assembly (14) and symmetrically coupled to the fuselage a wing (16) and an empennage (14a), at least one turbine engine (20) and power assemblies intended to power the blades (41), which are configured to be slowed down, paused and folded or unfolded and restarted in flight, respectively, by propeller brake devices and blade folding and unfolding mechanisms (60), in addition to mechanisms for controlling the collective pitch (50) of at least one pair of propellers (40), characterized in that it comprises at least one rotational energy source configured to power the propellers (40);a pair of canard-like side surfaces is integral with the nose (11), the tail assembly (14), or both; the propeller (40) is operatively supported by an elongated cylindrical housing member referred to as a nacelle (44), which is supported on at least one of: the pair of nose side surfaces (12), the pair of tail side surfaces (15), the wing (16), and the empennage (14a); the nacelle (44) houses at least one linear actuator (61) of a blade folding and unfolding mechanism (60) and at least one interposed linear actuator (51) of a collective pitch control mechanism (50), both non-rotating and aligned in tandem around, but not in contact with, a drive shaft (43), operatively associated with both the rotational power source and a propeller brake, which selectively slows and stops the rotation of the propellers (40) during flight, after a clutch has disengaged the rotational power source;a propeller hub (42), through which the driving shaft (43) extends, mounts a plurality of blades (41) configured to be folded between a plane of rotation and a folded position in which they are aligned lengthwise in the direction opposite to flight; a blade root handle (41a) engages a blade root for movement about the longitudinal axis of the blade (41) and is coupled to the propeller hub (42) for movement about; of a folding axis or hub lug axis (42c) supported between a pair of hub lugs (42a), the hub lug axis (42c) being perpendicular to both the driving axis (43) and the longitudinal axis of the blade (41) supported thereby; wherein the linear actuator (61) folds or unfolds the blades (41) by axially translating along the driving axis (43) the interposed linear actuator (51) and a first mechanical assembly associated therewith which converts the linear motion into circular motion of the blades (41) about the hub lug axes (42c); and wherein the interposed linear actuator (51) changes the collective pitch by axially translating a second mechanical assembly associated therewith which converts the linear motion into circular motion of the blades (41) about their longitudinal axes.

2. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized by the fact that the propeller (40) is of a pusher configuration.

3. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized by the fact that at least one pair of propellers (40) is driven in rotation by at least one electric motor.

4. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from takeoff to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized in that the electric motor and the propeller brake are housed in at least one of: nose (11), belly (13) and tail assembly (14) and output shafts (31) meshed with transmission shafts (33) are housed in at least one of: nose side surfaces (12), tail side surfaces (15), wing (16) and empennage (14a).

5. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized in that the electric motor and the propeller brake are housed in at least one nacelle (44).

6. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized by the fact that at least one pair of propellers (40) is driven in rotation by at least one internal combustion engine.

7. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized in that a nacelle support (45) is a hollow cylinder that supports the nacelle (44) rotatably about a vertical axis, with respect to the positioning of the aircraft (10) in straight and level flight, comprises a flange (45a) on one edge and is integral on the other edge with at least one of: nose side surface (12), tail side surface (15), wing (16) and empennage (14a).

8. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 7, characterized in that a lateral steering mechanism (70) provided with a linear actuator (71) connects the nacelle (44) to a fulcrum (45c) from which the linear actuator (71) moves the nacelle around the nacelle support (45).

9. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized in that the nacelle (44) is supported in a fixed manner in relation to the nacelle support (45).

10. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized in that said first mechanical assembly associated with the interposed linear actuator (51) comprises a longitudinal extension of a radially internal cylindrical surface or axially extended tubular portion (51c) of the interposed linear actuator (51), which is provided at its distal end with a non-rotating track (51d) of rolling elements, which receive in coupling a rotating ring (54) integral with cylinders with toothed bar (65), meshed with cylindrical gears (66) of the hub loop shafts (42c);wherein the cylindrical gears (66) convert the linear motion of the toothed bar cylinders (65) into circular motion of the blade root lugs (41a) about the hub lug axes (42c).; 11. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized in that said second mechanical assembly associated with the interposed linear actuator (51) is configured to translate axially along the driving axis (43) a non-rotating ring (52) coupled by rolling elements to a rotating ring (53), which is integral with toothed bar cylinders (55) meshed with cylindrical gears or cylindrical portions of cylindrical / bevel gears (56), in turn meshed with blade bevel gears (41 c); in which the cylindrical / bevel gears (56) convert the linear motion of the toothed bar cylinders (55) into circular motion of the blades (41) around their longitudinal axes.

12. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 1, characterized in that the propeller hub (42) is provided with a conical propeller fairing (46) or spinner comprising blade niches (46a) in which the blades (41) are partially housed while folded.

13. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to any one of the previous claims, characterized in that the tail assembly (14) is a V-tail provided with the turbine engine (20) operationally supported on the axis of symmetry and comprises a mechanical assembly in which an output shaft (21) powered by a front fan of the turbine engine (20) is engaged with a transmission shaft (22) connected with a pair of propellers (40), with an electric generator housed in the tail assembly (14) or both;the output shaft (21) and the drive shaft (22) are housed in a fairing (23) which is stationary relative to a turbine engine nacelle (20) and comprises an axially elongated conical portion supported by an output shaft support (21a) in turn supported on the output shaft (21), and a cylindrical portion flattened and tapered at the leading and trailing edges, which extends from the axially elongated conical portion in a vertical direction, with respect to positioning the aircraft (10) in straight and level flight, is integral with an inner bottom face of the turbine engine nacelle (20) and operatively supports a bearing (22b) of the drive shaft (22).; 14. Aircraft (10) provided with a hybrid air propulsion system by blades (41) of propellers (40) that are paused and folded at the end of the path from take-off to the top of the climb in level flight and by air jet thrust in cruise flight, according to claim 13, characterized by the fact that the output shaft (21) is positioned downstream of the front fan of the turbine engine (20). DECLARATION UNDER ARTICLE 19(1) I hereby declare that, for the sake of clarity, I have rewritten the set of claims, deleting some, adding others, and modifying some of the originals, moving the characteristic portion, without, however, leaving or altering the patent's inventive concept. The amendments do not add any new material.

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