Hoverable aircraft and related control methods

Abstract

The aircraft (1) capable of hovering comprises a fuselage (2), at least one rotor (3a, 3b, 4) rotatable relative to the fuselage (2), electric drive means adapted to rotate the rotor (3a, 3b, 4) and powered by a battery (9), and a cooling system (10) for the battery (9). The cooling system (10) further comprises a first opening (20) for air entry, a second opening (21) for air exit, and a passage (22) that places the first opening (20) in fluid communication with the second opening (21) and within which the battery (9) is disposed. The cooling system (10) further comprises a fan 23 adapted to increase the kinetic energy of the air contained in the passage 22, the fan 23 being activated when the forward speed (v) of the aircraft (1) relative to the ground is below a speed threshold (v0) and / or when the temperature (T) of the battery (9) exceeds a temperature threshold (T0).

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority from European Patent Application No. 22188969.4, filed August 5, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to an aircraft capable of hovering, such as a helicopter, convertiplane, or heliplane.

[0003] The present invention also relates to a method for controlling an aircraft capable of hovering. [Background technology]

[0004] In the aviation sector, airplanes are typically used for high cruising speeds, specifically above 150 knots, and high altitudes, e.g., above 30,000 feet. At high cruising speeds and altitudes, airplanes use fixed wings to generate the lift necessary to support themselves. A sufficient amount of this lift can only be obtained by accelerating the airplane over a considerable length of runway, which is also required for landing the same airplane.

[0005] In contrast, helicopters typically have a cruising speed lower than that of airplanes, generating the lift necessary for support through the rotation of their main rotor blades. As a result, helicopters can land and take off using particularly small surfaces without requiring horizontal speed. Furthermore, helicopters can hover and fly at relatively low altitudes and speeds, making them particularly maneuverable and suitable for demanding maneuvers, such as mountain or sea rescues.

[0006] Nevertheless, helicopters have inherent limitations regarding their maximum operating altitude, which is approximately 20,000 feet, and their maximum operating speed, which cannot exceed 150 knots.

[0007] To meet the demand for an aircraft that can offer the same dexterity and comfort as a helicopter, while overcoming the inherent limitations mentioned above, convertiplanes and heliplanes are known.

[0008] An example of a convertiplane is described in US Pat. No. 5,629,999.

[0009] More particularly, the convertiplane described in the aforementioned application comprises: a body extending along a first longitudinal axis; - a wing formed as a cantilever by a pair of half wings respectively arranged on opposite parts of the fuselage, the wing having respective free ends opposite the fuselage and aligned along a second transverse axis substantially perpendicular to the first longitudinal axis; It essentially has:

[0010] Convertiplanes are a pair of nacelles housing each of the motors; - a pair of rotors rotatable about respective third axes and operatively connected to respective motors; Further provided are:

[0011] The rotor is tiltable relative to the blade about a fourth axis that is preferably parallel to the second axis.

[0012] Convertiplanes are - a first "airplane" configuration in which the rotors are arranged with respective third axes substantially parallel to the first axis of the same convertiplane and coaxial with the respective engines; - a second "helicopter" configuration in which the rotors are arranged with respective third axes that are substantially vertical and orthogonal to the first axis of the convertiplane and orthogonal to the respective motors; can be taken selectively.

[0013] The ability to tilt the rotors allows the convertiplane to take off and land like a helicopter, i.e., in a direction substantially perpendicular to the first longitudinal axis of the convertiplane, without the need for a runway.

[0014] Additionally, convertiplanes are able to take off and land on rough terrain without producing noise levels that are unsuitable for urban residential areas.

[0015] Also, convertiplanes are capable of hovering when deployed in a helicopter configuration.

[0016] Additionally, convertiplanes, when deployed in the airplane configuration, can reach and maintain cruising speeds of approximately 250-300 knots and flight altitudes on the order of 30,000 feet.

[0017] This cruising speed is significantly higher than the maximum cruising speed of a helicopter, which is approximately 150 knots.

[0018] Similarly, the above altitudes are well above typical altitudes for helicopters, allowing a convertiplane deployed in an airplane configuration to avoid clouds and atmospheric turbulence characteristic of lower altitudes.

[0019] A heliplane such as the EUROCOPTER X-3 aircraft, in addition to components typically found in known helicopters, such as a main rotor with a vertical axis, comprises a pair of half wings cantilevered from respective parts of the fuselage of the heliplane along a fourth transverse axis that is substantially perpendicular to the fifth longitudinal axis of the aircraft and the axis of rotation of the main rotor.

[0020] More particularly, each half-wing carries a respective propeller comprising, in known manner, a drive shaft operable by an associated motor and a plurality of blades articulated to the drive shaft itself.

[0021] Specifically, each drive shaft is rotatable about an associated sixth axis, a horizontal axis, that is substantially parallel to the longitudinal axis of the heliplane.

[0022] As such, a heliplane can take off and land vertically using the main rotors, and fly in forward flight using the propellers and said half wings, in the same manner as a convertiplane.

[0023] During forward flight, the main rotor idles while thrust is generated by the propeller.

[0024] Electrically propelled or hybrid propelled aircraft are known in which at least one propulsion element (e.g., a propeller or rotor) is operable by an electric motor powered by a battery.

[0025] In such aircraft, the temperature of the batteries must be kept strictly within a temperature range, and indeed, an uncontrolled increase in the temperature of the batteries can lead to a condition known as "thermal runaway," which can cause fires or explosions, and which can have dangerous consequences for the entire aircraft.

[0026] In the field of electric or hybrid propulsion aircraft, several battery cooling solutions have been developed, including those shown in U.S. Patent Nos. 5,629,999; ... and 5,629,999.

[0027] According to these solutions, the batteries of the aircraft are placed inside cooling ducts available in the fuselage or wings and are impinged by air currents due to the motion of the aircraft itself.

[0028] However, such solutions, which have been developed specifically for airplanes, do not make it possible to effectively regulate the temperature of the batteries of aircraft capable of hovering.

[0029] US Patent No. 5,929,999 discloses an aircraft nacelle having first and second heat exchanger sections for cooling the aircraft during different modes, with fans and other components configured to maximize efficiency and cooling capacity during multiple operating conditions.

[0030] Patent Document 8 discloses an air-cooled double-stack fuel cell built-in power system for a fixed-wing unmanned aerial vehicle. The system includes a fuselage, a power motor, a high-pressure hydrogen storage tank, wings, two air-cooled fuel cell stacks symmetrically arranged in the center of the fuselage or on the wings, and two heat dissipation systems corresponding to the air-cooled fuel cell stacks. The air flow passage of the pile is a parallel corrugated flow path. When the pile is arranged in the center of the machine body, the cooling system further includes a cooling fan. When the pile is arranged on the wing, the power system is suitable for unmanned aerial vehicles with auxiliary propellers on the wings, and the heat dissipation system further includes a wing forward air guide cover. When the unmanned aerial vehicle is started or flies at low, medium, and high speeds, the reaction temperature of the pile is controlled to be within an ideal temperature interval through different heat dissipation modes.

[0031] Patent Document 9 discloses a multi-rotor helicopter having a fuselage and multiple fan units. Each fan unit is equipped with a circular fan frame, rotor blades, and a drive system cooling unit. Each drive system cooling unit has a housing housing that houses at least one of the drive unit, driver, and power supply, a cooling fan that supplies cooling air to the housing housing, an intake passage that guides air from the cooling fan toward the housing housing, and an exhaust passage that discharges the air that has passed through the housing housing. The exhaust passage discharges the air that has passed through the housing housing in a tangential direction of the fan frame.

[0032] In aircraft capable of hovering, the risk of the battery temperature increasing in an uncontrolled manner is in fact particularly high, especially while hovering: clearly, in this flight state, the airflow received by the aircraft and directed to heat exchange with the batteries is much less than during forward flight.

[0033] There is a recognized need in the industry to have aircraft that can hover and efficiently regulate the temperature of their batteries. [Prior art documents] [Patent documents]

[0034] [Patent Document 1] U.S. Patent No. 10,011,349 [Patent Document 2] U.S. Patent No. 10,177,424 [Patent Document 3] International Publication No. 2021 / 064374 Brochure [Patent Document 4] European Patent No. 3 176 851 [Patent Document 5] U.S. Patent No. 9,415,878 [Patent Document 6] U.S. Patent No. 3,957,230 [Patent Document 7] International Publication No. 2021 / 222528 Brochure [Patent Document 8] Chinese Patent Application Publication No. 113193209 [Patent Document 9] International Publication No. 2021 / 106549 Brochure Summary of the Invention [Problem to be solved by the invention]

[0035] The object of the present invention is to realize an aircraft capable of hovering that is able to meet the above-stated requirements in a simple and economical way. [Means for solving the problem]

[0036] According to the present invention, this object is achieved by an aircraft capable of hovering as claimed in claims 1 and 7 and by a method for controlling an aircraft capable of hovering as claimed in claims 14 and 16.

[0037] For a better understanding of the invention, preferred non-limiting embodiments are disclosed below, by way of example only, with the aid of the accompanying drawings, in which: [Brief explanation of the drawings]

[0038] [Figure 1A] 1 is a side view, with parts removed for clarity, of an aircraft according to the invention, with a cooling system, in a first operating configuration; FIG. [Figure 1B] FIG. 1B is a side view of the aircraft shown in FIG. 1A in a second operational configuration. [Figure 2] FIG. 2 is a perspective view of the aircraft of FIGS. 1A and 1B on an enlarged scale with portions removed for clarity. [Figure 3] FIG. 1C is an exploded view of the cooling system of FIGS. 1A and 1B, with portions removed for clarity. [Figure 4] FIG. 4 is a top view of the cooling system of FIGS. 1A, 1B, and 3, with portions removed for clarity. [Figure 5] 5 is a detail of FIG. 4 in partial cross section on a greatly enlarged scale. [Figure 6] 6 is a cross-sectional view, with parts removed for clarity, taken along line VI-VI in FIG. 1A. DETAILED DESCRIPTION OF THE INVENTION

[0039] With reference to Figures 1A and 1B, the numeral 1 designates an aircraft capable of hovering at least partially with electric propulsion.

[0040] More specifically, the aircraft 1 is - a first configuration (Fig. 1A) in forward flight and following a predominantly horizontal trajectory; a second configuration (Figure 1B) in which the aircraft performs a hover maneuver or moves forward along a predominantly vertical trajectory; It is a convertiplane that can be selectively switched between

[0041] It should be made clear that in the following disclosure, expressions such as "above," "below," "in front of," and "behind" are used with reference to the normal forward flight or "hovering" state of aircraft 1.

[0042] It is integral to Aircraft 1 and has its origin at the center of gravity of Aircraft 1 itself. - the longitudinal axis Y of the same aircraft 1; - axis X perpendicular to axis Y; - Axis Z perpendicular to axes X and Y; It is possible to identify three axes formed by

[0043] It is also possible to define a median plane M of the aircraft 1 relative to the axis X, oriented parallel to the axis Y.

[0044] Aircraft 1 is a fuselage 2 elongated along a longitudinal Y-axis; a plurality of rotors 3a, 3b, 4 rotatable relative to the fuselage 2 about respective axes of rotation B, C, D, E, F, G; - electric drive means, not shown, adapted to rotate at least one of the rotors 3a, 3b and 4; a plurality of batteries 9 adapted to power the electric drive means; a cooling system 10 for the battery 9; It essentially has:

[0045] In particular, the cooling system 10 is adapted to regulate the temperature T of the battery 9 by means of heat exchange between an airflow taken from the outside and the battery 9 .

[0046] The aircraft 1 may further comprise one or more thermal motors for driving one or more of the rotors 3a, 3b, and 4. In other words, the aircraft 1 may involve hybrid propulsion.

[0047] 1A and 1B, the fuselage 2 defines a nose 5 and a tail 6 of the aircraft 1 that are opposite each other along a longitudinal axis Y. The fuselage 2 also includes a torso section 7 that is interposed between the nose 5 and the tail 6 along the longitudinal axis Y.

[0048] In particular, the fuselage 7 is adapted to point towards the ground during normal operation of the aircraft 1 .

[0049] Referring to normal forward flight operating conditions, the aircraft 1 travels at a forward velocity v relative to the ground in a direction oriented from tail 6 to nose 5 (FIG. 1A).

[0050] More specifically, the aircraft 1 is a pair of semi-wings 8 cantilevered from opposite side walls 62 of the fuselage 2 and extending transversely to the axis Y (FIG. 2); - a pair of rotors 3a rotatable relative to the fuselage 2 about respective fixed axes of rotation B, C; - a pair of rotors 3b rotatable relative to the fuselage 2 about respective fixed axes of rotation D, E; - a pair of rotors 4 rotatable about respective axes F, G and tiltable relative to axis H between a first position, which is assumed when the aircraft 1 is in a first configuration, and a second position, which is assumed when the aircraft 1 is in a second configuration; Equipped with.

[0051] In particular, the axis H is parallel to the axis X.

[0052] Axes B, C and D, E lie in two planes parallel to axes X and Z, respectively.

[0053] Additionally, axes B and C are incident to one another and are inclined relative to axis Z, specifically at a point disposed above body 7. More specifically, axes B and C are both inclined at 10° relative to axis Z.

[0054] Like axes B and C, axes D and E are incident to one another and are inclined relative to axis Z, specifically at a point disposed above barrel 7. More specifically, axes D and E are both inclined at 10° relative to axis Z.

[0055] The rotors of each pair of rotors 3a and 3b are arranged symmetrically with respect to the median plane M. The pair of rotors 3a is arranged at the nose 5, the pair of rotors 3b is arranged at the tail 6, and the pair of rotors 4 is interposed along the longitudinal axis Y between the pair of rotors 3a and the pair of rotors 3b.

[0056] The axes F, G are arranged perpendicular to the axes B, C; D, E and parallel to the axis Y when the rotor 4 is arranged in the first position.

[0057] Axes F and G are arranged parallel to axis Z when rotor 4 is arranged in the second position (FIG. 1B).

[0058] Preferably, the rotors 3a, 3b and 4 have a fixed pitch.

[0059] In the embodiment shown, each of the rotors 3a, 3b and 4 is driven by a respective electric motor of the electric drive means, in particular each electric motor being operable independently of the other electric motors.

[0060] Aircraft 1 further comprises a control unit 60 (shown only diagrammatically in FIG. 5 ) that is programmed to receive as inputs a plurality of control signals provided by the crew, an autopilot, or a remote control system, and to provide as output a plurality of commands to command rotors 3 a, 3 b, and 4 so that rotors 3 a, 3 b, and 4 provide desired values ​​of associated thrust. More particularly, control unit 60 is programmed to command rotors 3 a, 3 b, and 4 to generate respective thrusts independently of each other.

[0061] Referring to FIG. 2, the cooling system 10 includes: - an opening 20 for the entry of air; a plurality of openings 21 for the air to exit; a passageway 22 extending through the body 2 and fluidly connecting the opening 20 with the opening 21; Equipped with.

[0062] Specifically, battery 9 is disposed within passage 22 and fluidly interposed between opening 20 and at least a portion of opening 21 .

[0063] Advantageously, the cooling system 10 comprises two fans 23 adapted to increase the kinetic energy of the air contained in the passage 22 (Figure 5), and these fans 23 are adapted to be operated when the forward speed v of the aircraft 1 relative to the ground is below a speed threshold v0 and / or when the temperature T of the battery 9 exceeds a temperature threshold T0.

[0064] For example, the temperature threshold T0 is lower than 75°C. Preferably, the temperature threshold T0 is equal to 60°C.

[0065] The control unit 60 is also operatively connected to the fans 23 to control their operation, i.e., to command their rotation about their respective axes of rotation I, J (FIG. 5).

[0066] In particular, the control unit 60 is adapted to deactivate or keep deactivated the fan 23 when the forward speed v is higher than a speed threshold v0 (e.g., during forward flight) and / or when the battery temperature T is lower than a temperature threshold T0. In this condition, the battery 9 is cooled by the flow of air entering the cooling system 10 through the openings 20 due to the effect of the relative motion of the aircraft 1 on the air in which it is surrounded. This type of cooling is called "ram ventilation".

[0067] Conversely, when the forward speed v is lower than the speed threshold v0 (e.g., while hovering) and / or when the battery temperature T is higher than the temperature threshold T0, the control unit 60 is adapted to operate the fan 23. In this state, the battery 9 enters the cooling system 10 through the opening 20 and is cooled by the flow of air forced by the action of the fan 23.

[0068] As shown in FIGS. 1A and 1B, opening 20 is located in nose 5 and opening 21 is located in barrel 7.

[0069] In particular, the opening 20 is centered relative to the median plane M (FIG. 2).

[0070] Preferably, the opening 20 further comprises: - a curved section 20a with an upward curvature, i.e. a curved section 20a along the axis Z towards the part of the aircraft 1 opposite the fuselage 7; a curved section 20b spaced apart from the curved section 20a parallel to the axis Z towards the body 7 and also having an upwardly directed curvature; two curved sections 20c, 20d, in particular in the form of circumferential arcs, connecting the curved sections 20a, 20b at their opposite ends parallel to the axis X; Equipped with.

[0071] In other words, the opening 20 has a curved oval shape, or bean shape.

[0072] The aircraft 1 further includes three containers 41, 42, 43 defining respective interior volumes 50, each containing a respective plurality of batteries 9. The batteries 9 within each interior volume 50 define a plurality of interstices 45 with each other and with the respective container 41, 42, 43.

[0073] In the embodiment shown, the containers 41, 42, and 43 are parallelepiped-shaped (FIG. 2). In particular, the containers 41, 42, and 43 have a square or substantially square base in a plane parallel to the axes X and Y. Furthermore, the extension of the containers 41, 42, and 43 parallel to the axis Z is smaller (for example, 1 / 5 or 1 / 6) than the extension of the containers 41, 42, and 43 parallel to the axes X and Y.

[0074] Furthermore, the containers 41, 42, 43 are aligned with one another parallel to the axis Y and centered relative to the median plane M.

[0075] Preferably, containers 41, 42, and 43 are identical to each other.

[0076] The cells 9 are shaped like parallelepipeds elongated along the direction K. The cells 9 are also parallel to one another, i.e., arranged such that the relative directions K coincide and are aligned with one another parallel to the axis X. In the illustrated embodiment, the direction K is parallel to the longitudinal axis Y. Within each container 41, 42, 43, the cells 9 are also fixed to one another.

[0077] In the embodiment shown, each container 41 , 42 , 43 contains five batteries 9 .

[0078] In particular, the temperature T of the battery 9 refers to the temperature at the outer surface of the battery 9 or in the vicinity of the battery 9, for example inside the containers 41, 42, 43.

[0079] As shown in Figures 2, 3 and 4, the passageway 22 is a duct 30 extending from the opening 20; three ducts 31, 32, 33 branching off from the duct 30 and fluidly connecting the duct 30 to the internal volume 50 of each of the containers 41, 42, 43, respectively; - Gap 45 and Equipped with.

[0080] More particularly, proceeding from the opening 20 along the longitudinal axis Y towards the tail 6, the duct 30 comprises a first section 30a and a second section 30b joined together.

[0081] The second section 30b is oriented parallel to the longitudinal axis Y, and the first section 30a extends obliquely relative to the second section 30b. In particular, the opening 20 is disposed below the second section 30b with respect to the axis Z.

[0082] The second section 30b also has a circular cross section, while the first section 30a has a cross section of gradually varying shape, specifically, the cross-sectional shape of the first section 30a first corresponds to the shape of the opening 20 and then merges into the circular cross section of the second section 30b (Figures 4 and 5).

[0083] Preferably, moreover, the passage cross section of the duct 30 has a progressively smaller extension from the opening 20 along the longitudinal axis Y towards the tail 6 .

[0084] More specifically, duct 31 fluidly connects second section 30b to interior volume 50 of container 41 and is oriented substantially parallel to axis Z. Duct 32 fluidly connects second section 30b to interior volume 50 of container 42. Ducts 31 and 32 are further centered relative to median plane M.

[0085] The duct 33 fluidly connects the second section 30b to the internal volume 50 of the container 43 and comprises two branches 33a, 33b arranged symmetrically with respect to the median plane M.

[0086] The cross section of the duct 31 has a constant or substantially constant extension parallel to the axis Z. The ducts 32 and 33 also have a constant or substantially constant extension along the longitudinal axis Y.

[0087] The passage 22 also comprises two auxiliary ducts 34, 35 in which a respective fan 23 is housed (Fig. 5).

[0088] Each of the auxiliary ducts 34, 35 has respective opposite ends 34a, 34b; 35a, 35b that face directly towards the duct 30 and are in fluid communication with the duct 30 (Figures 4 and 5).

[0089] More specifically, the auxiliary ducts 34, 35 are directly connected to the second section 30b of the duct 30.

[0090] Considering the cross section of the passage 22 passing through a plane perpendicular to the axis Z, the auxiliary ducts 34 and 35 are U-shaped and are arranged symmetrically with respect to each other with respect to the median plane M (FIG. 5).

[0091] Each auxiliary duct 34, 35 has a cross section with an extension that is smaller than the minimum extension of the cross section of duct 30. Also, the sum of the maximum extensions of the cross sections of auxiliary ducts 34 and 35 is smaller than the minimum extension of the cross section of duct 30.

[0092] As shown in FIG. 3, the openings 21 have a rectangular cross section in a plane perpendicular to the axis Z, are arranged parallel to each other and the longitudinal axis Y, and are spaced apart from each other parallel to the axis X.

[0093] In the embodiment shown in FIG. 3, containers 41, 42, and 43 each contain: - Cover 46 and - base plate 47; a set of side walls 48 extending parallel to the axis Z between the cover 46 and the base plate 47; Equipped with.

[0094] The set of cover 46, base plate 47, and sidewalls 48 of each vessel 41, 42, and 43 defines an interior volume 50 of the associated vessel.

[0095] Specifically, opening 21 is defined in base plate 47 .

[0096] Preferably, the covers 46 are fixed to each other and to the ducts 31, 32 and 33 (Fig. 3).

[0097] Aircraft 1 is - sensor means 65 adapted to detect the temperature T of the battery 9 and operatively connected to the control unit 60; - sensor means 70 adapted to detect the forward speed v of the aircraft 1 and operatively connected to the control unit 60; (Figure 5)

[0098] Preferably, the sensor means 70 comprises a flow meter adapted to detect the flow rate entering the aircraft 1 in use, parallel to the horizontal or substantially horizontal forward direction of the aircraft 1 .

[0099] The cooling system 10 further comprises means, not shown, for varying the flow rate of air entering through the openings 20 .

[0100] Such flow rate varying means may for example comprise a valve adapted to fractionate the flow rate of the incoming air and operably connected to the control unit 60 .

[0101] In particular, the control unit 60 is programmed to command partial flow of air entering through the valve when the temperature T of the battery 9 is lower than a minimum temperature threshold Tmin, which is lower than the temperature threshold T0. For example, the minimum temperature threshold Tmin is equal to 0°C.

[0102] The operation of the aircraft 1 according to the invention is described below.

[0103] In use, aircraft 1 is arranged in a second configuration for landing and takeoff, with rotors 4 positioned in a second position (FIG. 1B). In this second configuration, the lift required to support aircraft 1 is provided by rotors 3a, 3b, and 4.

[0104] During the transition of the aircraft from the first configuration to the second configuration, the control unit 60 is programmed to reduce the thrust generated by the rotors 3a and 3b as the axes F, G of the rotors 4 gradually approach parallelism with the axis Y and the speed v of the aircraft 1 increases.

[0105] Aircraft 1 moves forward at cruising speed in a first configuration with rotors 4 positioned in a first position (FIG. 1A). In this first configuration, the lift required to support aircraft 1 is provided for the most part by at least half wings 8 and / or other aerodynamic surfaces positioned along aircraft 1. Rotors 3a and 3b can be deactivated if necessary.

[0106] In use, the sensor means 65 detects the temperature T of the battery 9 and / or the sensor means 70 detects the forward velocity v.

[0107] If the forward speed v is greater than the speed threshold v0 and / or if the temperature T is less than the temperature threshold T0, the control unit 60 deactivates the fan 23 or keeps the fan 23 deactivated.

[0108] In particular, when fan 23 is deactivated, air enters cooling system 10 through opening 20, traverses duct 30, is distributed between ducts 31, 32 and 33, and reaches containers 41, 42 and 43 due to the effect of the motion of aircraft 1. Within the interior volumes 50 of containers 41, 42 and 43, the air flows through gaps 45, absorbs heat from batteries 9 and then exits through opening 21.

[0109] More specifically, while traversing the passageway 22, the airflow passes mostly through the second section 30b and minimally through the auxiliary ducts 34, 35 due to the cross-sectional dimensions of the auxiliary ducts 34, 35 relative to the cross-sectional dimensions of the second section 30b.

[0110] Conversely, if the forward speed v is below the speed threshold v0 (for example when the aircraft 1 is hovering) or if the temperature T exceeds the temperature threshold T0, the control unit 60 activates the fan 23.

[0111] In particular, when the fan 23 is operating, the air passes through the same ducts in sequence as it passes through when the fan 23 is deactivated. However, because the fan 23 is operating, the kinetic energy of the air is increased, and forced ventilation of the battery 9 is achieved.

[0112] During operation of the aircraft 1, if the temperature T of the battery 9 falls below the minimum temperature threshold Tmin, the control unit 60 commands the partial flow of incoming air. In this way, the amount of heat removed from the battery 9 is reduced.

[0113] An investigation of the characteristics of aircraft 1 shows the advantages that aircraft 1 can obtain.

[0114] The cooling system 10 comprises a fan 23 that performs forced ventilation when the forward speed v is below a speed threshold v0 and / or when the temperature T exceeds a temperature threshold T0, and therefore is able to effectively regulate the temperature of the batteries 9 of the aircraft 1. This is particularly the case when the aircraft 1 is hovering and therefore has a limited air flow rate through the openings 20, or is in any case characterized by low kinetic energy.

[0115] Because the opening 20 is located in the nose 5, it is possible to maximize the flow rate of air entering through the opening 20 itself. At the same time, because the opening 21 is located in the fuselage 7, the air flow exiting the cooling system 10 does not interfere with the aerodynamics of the aircraft 1.

[0116] Because the fans 23 are arranged in the auxiliary ducts 34, 35 respectively, when the fans 23 are deactivated they do not constitute an obstacle to the passage of air and the air passes through the duct 30 substantially unimpeded.

[0117] It will be apparent that the aircraft 1 described and shown herein may be subject to improvements and modifications without departing from the scope of protection defined by the claims.

[0118] The aircraft 1 may be a helicopter or a heliplane.

[0119] At least some, or all, of the rotors 3a, 3b and 4 may be variable pitch.

[0120] The passage 22 may be provided with a single auxiliary duct 34, 35 or with three or more auxiliary ducts 34, 35.

[0121] The cooling system 10 may include a single fan 23 or two or more fans 23. Specifically, the cooling system 10 may include two or more fans 23 for each of the auxiliary ducts 34, 35.

[0122] The aircraft 1 may be equipped with one or two containers 41, 42, 43 or even more than three containers 41, 42, 43. Also, the containers 41, 42, 43 do not have to be aligned with each other.

[0123] The passageway 22 may comprise a single duct 30 fluidly connecting the opening 20 to a single container 41, 42, or 43. Preferably, the single duct 30 fluidly connects the opening 20 directly to the single container 41, 42, 43. In other words, the passageway 22 may not comprise a duct 31, 32, 33. According to this embodiment, one or more auxiliary ducts 34, 35 comprise respective first and second ends 34a, 35a, 34b, 35b that both face directly toward the single duct 30.

[0124] The direction K of the cells 9 may be arranged parallel to the axis X, and the cells 9 may be aligned with one another along the longitudinal axis Y. Additionally or alternatively, the openings 21 may be arranged parallel to one another or to the axis X, or may be spaced apart from one another parallel to the longitudinal axis Y.

[0125] The sensor means 65 , 70 may be directly connected to avionics devices on board the aircraft 1 or may be connected to a control unit other than the control unit 60 . [Explanation of symbols]

[0126] 1 aircraft 2. Torso 3a, 3b, 4 rotor 5 Nose 6 Tail 7. Torso 9 batteries 10 Cooling System 20 Air opening 20a, 20b, 20c, 20d curved areas 21 Air outlet opening 22 Passage 23 Fans 30 Duct 30a First Section 30b Second District 31, 32, 33 Branch duct 33a, 33b Branch 34, 35 Auxiliary duct 34a, 34b, 35a, 35b ends 41, 42, 43 containers 45 Gap 46 Cover 47 Foundation plate 48 Side wall 50 internal volume 60 Control Unit 62 Side wall 65 Sensor means 70 Sensor means B, C, D, E, F, G rotation axis H-axis I, J rotation axis K Battery 9 Orientation M median plane T Temperature of battery 9 v Forward speed X, Y, and Z axes

Claims

1. An aircraft (1) capable of hovering, a body (2) elongated along a longitudinal axis (Y); at least one rotor (3a, 3b, 4) rotatable about an axis of rotation relative to the fuselage (2); electric drive means adapted to rotate said at least one rotor (3a, 3b, 4); at least one battery (9) adapted to power said electric drive means; a cooling system (10) for said at least one battery (9); Equipped with The cooling system (10) comprises: a first opening (20) adapted to admit air; a plurality of second openings (21) adapted to allow air to exit; a passage (22) fluidly connecting said first openings (20) with at least some of said second openings (21); Equipped with the at least one battery (9) is disposed in the passage (22) and fluidly interposed between the first openings (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23) adapted to increase the kinetic energy of the air contained in the passage (22); the fan (23) is operated, in use, when the forward speed (v) of the aircraft (1) relative to the ground is below a speed threshold (v0) and / or when the temperature (T) of the at least one battery (9) exceeds a temperature threshold (T0); the aircraft comprises at least one container (41, 42, 43) defining an interior volume (50) within which a plurality of the batteries (9) are contained, the batteries (9) within the interior volume (50) defining a plurality of gaps (45) between each other and the containers (41, 42, 43); The passage (22) a first duct (30) extending from the first opening (20); at least one second duct (31, 32, 33) branching from said first duct (30) and fluidly connecting said first duct (30) to said internal volume (50) of each of said containers (41, 42, 43); The gap (45); An aircraft (1), characterized in that it comprises:

2. 2. The aircraft of claim 1, wherein the aircraft comprises at least two vessels (41, 42, 43) each defining an interior volume (50), and the passage (22) comprises at least two second ducts (31, 32, 33) branching from the first duct (30) and fluidly connecting the first duct (30) to the respective interior volumes (50) of the vessels (41, 42, 43).

3. The fuselage (2) a nose (5) of the aircraft (1); a tail (6) of the aircraft (1) opposite the nose (5) along the longitudinal axis (Y); a body (7) interposed between the nose (5) and the tail (6) along the longitudinal axis (Y); and 3. An aircraft according to claim 1 or 2, wherein the first opening (20) is arranged in the nose (5) and the second opening (21) is arranged in the fuselage (7).

4. The first duct (30) comprises a first section (30a) and a second section (30b), the first section (30a) fluidly connects the first opening (20) to the second section (30b); 4. An aircraft according to claim 3, wherein the first opening (20) is closer to the fuselage (7) than the second section (30b) along a first axis (Z) of the aircraft (1) that is perpendicular to the longitudinal axis (Y) and that is vertical in use.

5. 5. An aircraft according to any one of claims 1 to 4, wherein the first duct (30) has an area that gradually decreases as it progresses from the first opening (20) along the longitudinal axis (Y).

6. The passage (22) further comprises at least one auxiliary duct (34, 35); each of said auxiliary ducts (34, 35) having a first end (34a, 35a) and a second end (34b, 35b) opposite each other; Both the first and second ends (34a, 35a; 34b, 35b) face directly towards the first duct (30); An aircraft as claimed in any one of claims 1 to 5, wherein each of the fans (23) is arranged in a respective auxiliary duct (34, 35).

7. An aircraft (1) capable of hovering, a body (2) elongated along a longitudinal axis (Y); at least one rotor (3a, 3b, 4) rotatable about an axis of rotation relative to the fuselage (2); electric drive means adapted to rotate said at least one rotor (3a, 3b, 4); at least one battery (9) adapted to power said electric drive means; a cooling system (10) for said at least one battery (9); Equipped with The cooling system (10) comprises: a first opening (20) adapted to admit air; a plurality of second openings (21) adapted to allow air to exit; a passage (22) fluidly connecting said first openings (20) with at least some of said second openings (21); Equipped with the at least one battery (9) is disposed in the passage (22) and fluidly interposed between the first openings (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23) adapted to increase the kinetic energy of the air contained in the passage (22); the fan (23) is operated, in use, when the forward speed (v) of the aircraft (1) relative to the ground is below a speed threshold (v0) and / or when the temperature (T) of the at least one battery (9) exceeds a temperature threshold (T0); the aircraft comprises at least one container (41, 42, 43) defining an interior volume (50) within which a plurality of the batteries (9) are contained, the batteries (9) within the interior volume (50) defining a plurality of gaps (45) between each other and the containers (41, 42, 43); said passage (22) comprising at least one duct (30) fluidly connecting said first opening (20) to said at least one container (41, 42, 43); the passage (22) further comprises at least one auxiliary duct (34, 35); each said auxiliary duct (34, 35) having a first end (34a, 35a) and a second end (34b, 35b) opposite each other; Both of said first and second ends (34a, 35a; 34b, 35b) face directly towards said duct (30); each said fan (23) is arranged in a respective auxiliary duct (34, 35).

8. 8. An aircraft according to claim 7, comprising two auxiliary ducts (34, 35) arranged symmetrically with respect to a median plane (M) of the aircraft (1) parallel to the longitudinal axis (Y).

9. a control unit (60) operatively connected to said at least one fan (23); a first sensor means (65) adapted to detect the temperature of said at least one battery (9) and operatively connected to said control unit (60); a second sensor means (70) adapted to detect a forward velocity (v) of said aircraft (1) and operatively connected to said control unit (60); 9. An aircraft according to claim 7 or 8, comprising:

10. 10. An aircraft according to claim 9, wherein said second sensor means (70) comprises a flow meter.

11. the aircraft comprises means for varying the flow rate of air entering through the first opening (20), operably connected to the control unit (60); the control unit (60) is programmed to instruct the flow rate varying means to partial the flow rate when, in use, the temperature (T) of the at least one battery (9) is below a minimum temperature threshold (Tmin); An aircraft according to claim 9 or 10, wherein the minimum temperature threshold (Tmin) is lower than the temperature threshold (T0).

12. The fuselage (2), a pair of half wings (8) respectively disposed on opposite portions of the fuselage (2), each having a free end opposite the fuselage (2), and aligned along a second axis transverse to the longitudinal axis (Y); at least a first pair of said rotor blades (4) rotatable about respective third axes (F, G) and tiltable relative to said half blades (8) about a fourth axis (H) transverse to said longitudinal axis (Y); 12. The aircraft of any one of claims 7 to 11, which is a convertiplane comprising:

13. The aircraft a second pair of rotors (3 a) rotatable about respective fifth axes (B, C) fixed relative to the fuselage (2); a third pair of rotors (3b) rotatable about respective sixth axes (B, C) fixed relative to the fuselage (2); Furthermore, the first pair of rotors (4) is interposed along the longitudinal axis (Y) between the second pair of rotors (3a) and the third pair of rotors (3b); 13. An aircraft as claimed in claim 12, wherein each rotor of the first, second or third pair (4, 3a, 3b) of rotors is operable independently of other rotors of the first, second or third pair (4, 3a, 3b) of rotors.

14. 1. A method for controlling an aircraft (1) capable of hovering, said aircraft comprising: a body (2) elongated along a longitudinal axis (Y); at least one rotor (3a, 3b, 4) rotatable about an axis of rotation relative to the fuselage (2); electric drive means adapted to rotate said at least one rotor (3a, 3b, 4); at least one battery (9) adapted to power said electric drive means; a cooling system (10) for said at least one battery (9); Equipped with The cooling system (10) comprises: a first opening (20) adapted to admit air; a plurality of second openings (21) adapted to allow air to exit; a passageway (22) that places the first openings (20) in fluid connection with at least some of the second openings (21); Equipped with the at least one battery (9) is disposed in the passage (22) and fluidly interposed between the first openings (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23) adapted to increase the kinetic energy of the air contained in the passage (22); the aircraft (1) further comprises at least one container (41, 42, 43) defining an interior volume (50) within which a plurality of the batteries (9) are contained, the batteries (9) within the interior volume (50) defining a plurality of gaps (45) between each other and the containers (41, 42, 43); The passage (22) a first duct (30) extending from the first opening (20); at least one second duct (31, 32, 33) branching from said first duct (30) and fluidly connecting said first duct (30) to said internal volume (50) of each of said containers (41, 42, 43); The gap (45); Equipped with activating the fan (23) when a forward speed (v) of the aircraft (1) relative to the ground is below a speed threshold (v0) and / or when a temperature (T) of the at least one battery (9) exceeds a temperature threshold (T0).

15. 15. The method of claim 14, wherein the aircraft (1) comprises at least two vessels (41, 42, 43) each defining an interior volume (50), and the passage (22) comprises at least two second ducts (31, 32, 33) branching from the first duct (30) and fluidly connecting the first duct (30) to the respective interior volumes (50) of the vessels (41, 42, 43).

16. 1. A method for controlling an aircraft (1) capable of hovering, said aircraft comprising: a body (2) elongated along a longitudinal axis (Y); at least one rotor (3a, 3b, 4) rotatable about an axis of rotation relative to the fuselage (2); electric drive means adapted to rotate said at least one rotor (3a, 3b, 4); at least one battery (9) adapted to power said electric drive means; a cooling system (10) for said at least one battery (9); Equipped with The cooling system (10) comprises: a first opening (20) adapted to admit air; a plurality of second openings (21) adapted to allow air to exit; a passageway (22) that places the first openings (20) in fluid connection with at least some of the second openings (21); Equipped with the at least one battery (9) is disposed in the passage (22) and fluidly interposed between the first openings (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23) adapted to increase the kinetic energy of the air contained in the passage (22); the aircraft (1) further comprises at least one container (41, 42, 43) defining an interior volume (50) within which a plurality of the batteries (9) are contained, the batteries (9) within the interior volume (50) defining a plurality of gaps (45) between each other and the containers (41, 42, 43); the passage (22) comprises at least one duct (30) fluidly connecting the first opening (20) to the at least one container (41, 42, 43); The passage (22) further comprises at least one auxiliary duct (34, 35); each of said auxiliary ducts (34, 35) having a first end (34a, 35a) and a second end (34b, 35b) opposite each other; Both of said first and second ends (34a, 35a; 34b, 35b) face directly towards said duct (30); Each of said fans (23) is disposed in a respective auxiliary duct (34, 35); activating the fan (23) when a forward speed (v) of the aircraft (1) relative to the ground is below a speed threshold (v0) and / or when a temperature (T) of the at least one battery (9) exceeds a temperature threshold (T0).

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