Aircraft capable of hovering and associated control method

Abstract

An aircraft (1) capable of hovering comprises a fuselage (2), at least one rotor (3a, 3b, 4) rotatable relative to the fuselage (2), electric drives adapted to rotate the rotor (3a, 3b, 4) and powered by a battery (9), and a cooling system (10) of the battery (9). The cooling system (10) in turn comprises a first opening (20) for air entry, a second opening (21) for air escape, and a channel (22) placing the first opening (20) in fluid communication with the second opening (21), the battery (9) being placed in the channel. The cooling system (10) further comprises a fan (23) adapted to increase the kinetic energy of the air contained in the channel (22), which fan is 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).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to European patent application No. 22188969.4 filed on August 5, 2022, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The invention relates to an aircraft capable of hovering, such as a helicopter or a vertical take-off and landing aircraft or a helicopter.

[0004] The invention also relates to a method for controlling an aerial vehicle capable of hovering. Background Art

[0005] In aviation, aircraft are usually used at high cruising speeds (especially greater than 150 knots) and high altitudes (for example above 30,000 feet). At high cruising speeds and high altitudes, aircraft use fixed wings to generate the lift required to sustain the aircraft itself. Sufficient value of this lift can only be obtained by accelerating the aircraft on fairly long runways. These runways are also necessary to allow the same aircraft to land.

[0006] In contrast, helicopters generally have a lower cruising speed than an airplane and generate the lift required for maintenance by the rotation of the main rotor blades. Thus, helicopters can land / take off without requiring horizontal speed and using particularly small surfaces. In addition, helicopters are able to hover and can fly at relatively low altitudes and speeds, thus resulting in being particularly maneuverable and suitable for demanding maneuvers, such as rescuing people in the mountains or at sea.

[0007] However, helicopters have inherent limitations in terms of their maximum operating altitude (approximately 20,000 feet) and maximum operating speed (no more than 150 knots).

[0008] In order to meet the need for an aircraft that can exhibit the same maneuverability and comfort of use as a helicopter and at the same time overcome the above-mentioned inherent limitations, vertical take-off and landing aircraft and helicopters are known.

[0009] An example of a VTOL aircraft is described in patent application US-B-10,011,349.

[0010] In more detail, the vertical take-off and landing reversing aircraft described in the above application basically includes:

[0011] - a fuselage extending along a first longitudinal axis; and

[0012] - a wing cantilevered and formed by a pair of half-wings arranged on respective mutually opposite parts of the fuselage and having respective free ends opposite the fuselage and aligned along a second transverse axis substantially orthogonal to the first longitudinal axis.

[0013] Vertical take-off and landing aircraft also include:

[0014] - a pair of nacelles housing respective motors; and

[0015] - A pair of rotors rotatable about respective third axes and operatively connected to respective motors.

[0016] The rotor is tiltable relative to the wing about a fourth axis, which is preferably parallel to the second axis.

[0017] VTOL aircraft can also optionally present:

[0018] a first "airplane" configuration in which the rotors are arranged with their respective third axes substantially parallel to the first axis of the VTOL aircraft and coaxial with the respective engines; or

[0019] - A second "helicopter" configuration, in which the rotors are arranged with their respective third axes being substantially vertical and orthogonal to the first axis of the VTOL aircraft and to the respective motors.

[0020] Because the rotors can be tilted, the VTOL aircraft can take off and land like a helicopter (ie, in a direction substantially perpendicular to the first longitudinal axis of the VTOL aircraft) without the need for a runway.

[0021] In addition, VTOL aircraft are able to take off and land on uneven terrain without generating noise levels that are incompatible with urban residential areas.

[0022] Additionally, when arranged in a helicopter configuration, the VTOL aircraft is capable of hovering.

[0023] Furthermore, when arranged in an airplane configuration, the VTOL aircraft can achieve and maintain a cruising speed of approximately 250-300 knots and a flight altitude of approximately 30,000 feet.

[0024] This cruising speed is well above the value of about 150 knots which limits the maximum cruising speed of a helicopter.

[0025] Similarly, the above altitudes are well above the typical altitudes for helicopters, allowing VTOL aircraft to be arranged in an aircraft configuration to avoid clouds and atmospheric disturbances typical of lower altitudes.

[0026] In addition to the components common in known helicopters, such as a main rotor with a vertical axis, a helicopter such as the EUROCOPTER X-3 aircraft also comprises a pair of half-wings cantilevered from respective parts of the fuselage of the helicopter along a fourth transverse axis substantially orthogonal to a fifth longitudinal axis of the aircraft and to the axis of rotation of the main rotor.

[0027] In more detail, each half-wing carries a respective propeller comprising, in a known manner, a drive shaft operable by a relative motor and a plurality of blades articulated on the drive shaft itself.

[0028] In particular, each drive shaft is rotatable about an associated sixth axis that is substantially parallel to the longitudinal axis of the helicopter (ie the horizontal axis).

[0029] The helicopter is thus able to take off and land in the vertical direction with the help of the main rotor, and to fly in forward flight with the help of the propeller and the aforementioned half-wings, in the same way as a VTOL aircraft.

[0030] During forward flight, the main rotor spins idly while thrust is generated by the propellers.

[0031] Electric or hybrid propulsion aircraft are known in which at least one propulsion element (eg a propeller or a rotor) is operable by an electric motor powered by a battery.

[0032] In such aircraft, the temperature of the batteries must be kept strictly within a temperature range. In fact, an uncontrolled increase in the battery temperature can lead to a condition known as "thermal runaway", in which a fire forms or an explosion is triggered, which can have catastrophic consequences for the entire aircraft.

[0033] In the field of electric or hybrid propulsion aircraft, many battery cooling solutions have been developed, including those shown in US-B-10,177,424, WO-A-2021 / 064374, EP-B-3176851, US9,415,878 and US3,957,230.

[0034] According to these solutions, the batteries of the aircraft are arranged in cooling ducts obtained in the fuselage or at the wings and are impacted by the air flows due to the movement of the aircraft itself.

[0035] However, this solution, which was developed specifically for aircraft, cannot effectively regulate the temperature of the batteries of an aircraft capable of hovering.

[0036] WO-A1-2021222528 discloses an aircraft nacelle having a first heat exchanger section and a second heat exchanger section to cool the aircraft during different modes. In addition, the fan and other components are configured to maximize efficiency and cooling capacity during multiple operating conditions.

[0037] CN-A-113193209 discloses an air-cooled fuel cell dual-stack integrated power system for a fixed-wing unmanned aerial vehicle. The system includes a fuselage, a power motor, a high-pressure hydrogen storage tank, a wing, two air-cooled fuel cell stacks symmetrically arranged in the middle of the fuselage or on the wing, and two heat dissipation systems corresponding to the air-cooled fuel cell stacks; the air flow channel of the electric pile is a parallel wave flow channel; when the electric pile is arranged in the middle of the machine body, the cooling system also includes a cooling fan; when the electric pile is arranged on the wing, the power system is suitable for an unmanned aerial vehicle with an auxiliary propeller on the wing, and the heat dissipation system also includes an air guide cover at the front of the wing; when the unmanned aerial vehicle is started or flies at low, medium and high speeds, the reaction temperature of the electric pile is controlled within an ideal temperature range through different heat dissipation modes.

[0038] WO-A1-2021106549 discloses a multi-rotor helicopter having a fuselage and a plurality of fan units. Each fan unit is equipped with a circular fan frame, a rotating blade, and a drive system cooling unit. Each drive system cooling unit has: a container for accommodating at least one of a drive unit, a driver, and a power supply; a cooling fan for supplying cooling air to the container; an intake flow path for guiding air from the cooling fan toward the container; and an exhaust flow path for discharging air that has passed through the container. The exhaust flow path discharges air that has passed through the container in a tangential direction of the fan frame.

[0039] In fact, in an aircraft capable of hovering, the risk of the temperature of the batteries increasing in an uncontrolled manner is particularly high, especially when hovering. Specifically, in such flight conditions, the air flow rate imparted to the aircraft and to be designated for heat exchanges with the batteries is much lower than during forward flight.

[0040] There is a perceived need in the industry to implement an aerial vehicle capable of hovering in which the temperature of the battery can be effectively regulated.

[0041] The object of the present invention is to realize an aerial vehicle capable of hovering which allows satisfying the above-mentioned needs in a simple and economical way. Summary of the invention

[0042] According to the invention, this object is achieved by a flying machine capable of hovering as claimed in claims 1 and 7 and by a method for controlling a flying machine capable of hovering as claimed in claims 14 and 16 . BRIEF DESCRIPTION OF THE DRAWINGS

[0043] For a better understanding of the invention, preferred non-limiting embodiments are described below, by way of example only, with the aid of the accompanying drawings, in which:

[0044] - Figure 1A is a side view of an aircraft according to the invention in a first operational configuration, including a cooling system and with parts removed for clarity;

[0045] - Figure 1B is in the second operating configuration Figure 1A A side view of the aircraft is shown;

[0046] - Figure 2 yes Figure 1A and Figure 1B is a perspective view of an aircraft of which the proportions are enlarged, with portions removed for clarity;

[0047] - Figure 3 yes Figure 1A and Figure 1B An exploded view of the cooling system with parts removed for clarity;

[0048] - Figure 4 yes Figure 1A , Figure 1B and Figure 3 A top view of the cooling system with parts removed for clarity;

[0049] - Figure 5 yes Figure 4 Details of a greatly enlarged local section; and

[0050] - Figure 6 It is along Figure 1A The section along line VI-VI in FIG. 1 is partially removed for clarity. DETAILED DESCRIPTION

[0051] Reference Figure 1A and Figure 1B , 1 represents an aircraft capable of hovering by at least partial electric propulsion.

[0052] In more detail, the aircraft 1 is a vertical take-off and landing aircraft that can selectively switch between the following configurations:

[0053] -First Structure( Figure 1A ), in which it is in forward flight and follows a predominantly horizontal trajectory; and

[0054] - Second construction ( Figure 1B ), in which it performs hovering maneuvers or moves forward along a primarily vertical trajectory.

[0055] It has to be specified that, in the following of the present disclosure, expressions such as “upper”, “lower”, “in front of”, “behind” etc. are used with reference to the normal forward flight or “hover” situation of the aircraft 1 .

[0056] It is possible to identify a triple axis integral with the aircraft 1 and having its origin at the centre of gravity of the aircraft 1 itself, which is formed by the following axes:

[0057] - the longitudinal axis Y of this same aircraft 1 ;

[0058] - an axis X orthogonal to the axis Y; and

[0059] - an axis Z perpendicular to the axes X,Y.

[0060] A median plane M of the aircraft 1 , oriented relative to the axis X and parallel to the axis Y, may also be defined.

[0061] The aircraft 1 basically comprises:

[0062] - a fuselage 2 elongated along a longitudinal axis Y;

[0063] - a plurality of rotors 3a, 3b, 4 rotatable relative to the fuselage 2 about respective axes of rotation B, C, D, E, F, G;

[0064] - electric drive means (not shown) suitable for rotating at least one of the rotors 3a, 3b and 4;

[0065] - a plurality of batteries 9 suitable for supplying power to the electric drive means; and

[0066] - A cooling system 10 for the battery 9 .

[0067] In detail, the cooling system 10 is adapted to adjust the temperature T of the battery 9 by means of heat exchange between the battery 9 and a flow of air taken from the outside.

[0068] The aircraft 1 may also 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 have hybrid propulsion.

[0069] like Figure 1A and Figure 1B As shown, the fuselage 2 defines a nose 5 and a tail 6 of the aircraft 1 , opposite each other along a longitudinal axis Y. Furthermore, the fuselage 2 comprises a belly 7 interposed along the longitudinal axis Y between the nose 5 and the tail 6 .

[0070] In detail, the belly 7 is adapted to face towards the ground during normal operation of the aircraft 1 .

[0071] With reference to normal forward flight operation, the aircraft 1 travels at a forward speed v relative to the ground in a direction directed from the tail 6 to the nose 5 ( Figure 1A ).

[0072] In more detail, the aircraft 1 comprises:

[0073] a pair of half-wings 8 extending cantilevered from respective mutually opposite side walls 62 of the fuselage 2 and transversely to the axis Y ( Figure 2 );

[0074] - a pair of rotors 3a rotatable relative to the fuselage 2 about respective fixed axes B, C;

[0075] a pair of rotors 3 b rotatable relative to the fuselage 2 about respective fixed axes D, E; and

[0076] A pair of rotors 4 rotatable about respective axes F, G and tiltable relative to axis H between a first position assumed when aircraft 1 is in the first configuration and a second position assumed when aircraft 1 is in the second configuration.

[0077] In detail, the axis H is parallel to the axis X.

[0078] The axes B, C and the axes D, E lie in two corresponding planes parallel to the axes X and Z.

[0079] Furthermore, axes B and C are associated with each other and are inclined relative to axis Z, in particular at a point arranged above abdomen 7. In more detail, axes B and C are both inclined relative to axis Z by 10°.

[0080] Similar to axes B and C, axes D and E are associated with each other and are inclined relative to axis Z, in particular at a point arranged above abdomen 7. In more detail, axes D and E are both inclined relative to axis Z by 10°.

[0081] The rotors in each pair of rotors 3a and 3b are arranged symmetrically with respect to the middle plane M. In addition, a pair of rotors 3a is arranged at the nose 5, a pair of rotors 3b is arranged at the tail 6, and a pair of rotors 4 is interposed along the longitudinal axis Y between the pair of rotors 3a and the pair of rotors 3b.

[0082] When the rotor 4 is arranged in the first position, the axes F, G are arranged orthogonal to the axes B, C; D, E and parallel to the axis Y.

[0083] When the rotor 4 is arranged in the second position ( Figure 1B ), axes F and G are arranged parallel to axis Z.

[0084] Preferably, the rotors 3a, 3b and 4 have a fixed pitch.

[0085] In the embodiment shown, each of the rotors 3a, 3b and 4 is driven by a respective electric motor of the electric drive. In detail, each electric motor can be operated independently of the other electric motors.

[0086] The aircraft 1 also includes a control unit 60 (only in Figure 5 ), the control unit 60 receives as input a plurality of control signals provided by the crew via an autopilot or a remote control system, and is programmed to provide as output a plurality of commands to command the rotors 3a, 3b and 4 so that they provide a desired value of the associated thrust. In more detail, the control unit 60 is programmed to command the rotors 3a, 3b and 4 to generate the respective thrusts independently of each other.

[0087] refer to Figure 2 , the cooling system 10 comprises:

[0088] - opening 20 for air entry;

[0089] - a plurality of openings 21 for air to escape; and

[0090] A channel 22 extending through the fuselage 2 and fluidically connecting the opening 20 with the opening 21 .

[0091] In particular, the battery 9 is placed within the channel 22 and is fluidly interposed between the opening 20 and at least a portion of the opening 21 .

[0092] Advantageously, the cooling system 10 comprises two fans 23 ( Figure 5 ); these fans 23 are adapted to operate 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.

[0093] For example, the temperature threshold T0 is lower than 75° C. Preferably, the temperature threshold T0 is equal to 60° C.

[0094] The control unit 60 is also operatively connected to the fans 23 to control their operation, ie to command the fans 23 to rotate about the respective rotation axes I, J ( Figure 5 )Rotate.

[0095] In detail, the control unit 60 is suitable for deactivating the fan 23 or keeping it deactivated when the forward speed v is greater than the speed threshold v0 (e.g. during forward flight) and / or the temperature T of the battery is lower than the temperature threshold T0. In this case, the battery 9 is cooled by the air flow entering the cooling system 10 through the opening 20, due to the effect of the relative movement of the aircraft 1 with respect to the air in which it is immersed. This type of cooling is known as "ram ventilation".

[0096] Conversely, when the forward speed v is below the speed threshold v0 (e.g., when hovering) and / or the temperature T of the battery is greater than the temperature threshold T0, the control unit 60 is adapted to activate the fan 23. In this case, the battery 9 is cooled by the air flow forced by the action of the fan 23 into the cooling system 10 through the opening 20.

[0097] like Figure 1A and Figure 1B As shown, the opening 20 is arranged on the nose 5 and the opening 21 is arranged on the abdomen 7 .

[0098] In detail, the opening 20 is relative to the middle plane M ( Figure 2 ) in the center.

[0099] Furthermore, preferably, the opening 20 comprises:

[0100] a curved section 20 a having a curvature facing upwards, ie towards the portion of the aircraft 1 opposite the belly 7 along the axis Z;

[0101] a curved section 20 b spaced apart from the curved section 20 a parallel to the axis Z, towards the abdomen 7 , and also having a curvature facing upwards; and

[0102] Two curved sections 20c, 20d, in particular in the form of circumferential arcs, which connect the curved sections 20a, 20b at their respective opposite ends parallel to the axis X.

[0103] In other words, the opening 20 has a curved elliptical shape, ie, a bean shape.

[0104] The aircraft 1 further comprises three containers 41, 42, 43 defining respective internal volumes 50 in which are housed respective plurality of batteries 9. The batteries 9 in each internal volume 50 define a plurality of voids 45 with each other and with the respective containers 41, 42, 43.

[0105] In the embodiment shown, the containers 41, 42 and 43 are parallelepiped-shaped ( Figure 2 ). In detail, the containers 41, 42 and 43 have a square or substantially square base in a plane parallel to the axes X and Y. In addition, the extension of the containers 41, 42 and 43 parallel to the axis Z is smaller than the extension of the containers 41, 42 and 43 parallel to the axes X and Y (for example, 1 / 5 or 1 / 6).

[0106] Furthermore, the containers 41 , 42 , 43 are aligned parallel to the axis Y with respect to one another and are centered relative to the median plane M.

[0107] Preferably, containers 41 , 42 and 43 are identical to each other.

[0108] The batteries 9 are shaped like an elongated parallelepiped along the direction K. Furthermore, the batteries 9 are parallel to one another (i.e. arranged so that the relevant directions K coincide) and are aligned parallel to one another in relation to the axis X. In the embodiment shown, the direction K is parallel to the longitudinal axis Y. Furthermore, within each container 41 , 42 , 43 , the batteries 9 are fixed to one another.

[0109] In the embodiment shown, each container 41 , 42 , 43 contains five batteries 9 .

[0110] In detail, 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 ).

[0111] like Figure 2 , Figure 3 and Figure 4 As shown, channel 22 includes:

[0112] - a duct 30 extending from the opening 20;

[0113] - three ducts 31 , 32 , 33 which branch off from the duct 30 and each fluidically connect the duct 30 to the inner volume 50 of the respective container 41 , 42 , 43 ; and

[0114] - Gap 45.

[0115] In more detail, proceeding along the longitudinal axis Y from the opening 20 towards the tail 6 , the duct 30 comprises a first section 30 a and a second section 30 b joined together.

[0116] 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 detail, the opening 20 is arranged relative to the axis Z below the second section 30b.

[0117] The second section 30b also has a circular cross section, while the first section 30a has a cross section with a gradually changing shape. In detail, the shape of the cross section of the first section 30a initially corresponds to the shape of the opening 20, and then connects to the circular cross section ( Figure 4 and Figure 5 ).

[0118] Furthermore, preferably, the passage cross section of the duct 30 has a gradually decreasing extension proceeding from the opening 20 along the longitudinal axis Y towards the tail 6 .

[0119] In more detail, the duct 31 fluidically connects the second section 30b to the internal volume 50 of the container 41 and is directed substantially parallel to the axis Z. The duct 32 fluidically connects the second section 30b to the internal volume 50 of the container 42. Furthermore, the ducts 31 and 32 are centered relative to the median plane M.

[0120] The duct 33 fluidically connects the second section 30 b to the internal volume 50 of the container 43 and comprises two branches 33 a, 33 b arranged symmetrically relative to the median plane M.

[0121] The cross section of the duct 31 has a constant or substantially constant extension parallel to the axis Z. Furthermore, along the longitudinal axis Y, the ducts 32 and 33 have a constant or substantially constant extension.

[0122] The channel 22 also includes two auxiliary ducts 34, 35, and the corresponding fans 23 are accommodated in the auxiliary ducts 34, 35 ( Figure 5 ).

[0123] Each of the auxiliary pipes 34, 35 comprises respective ends 34a, 34b; 35a, 35b opposite to each other. These ends 34a, 34b; 35a, 35b directly face the pipe 30 and are in fluid communication with it ( Figure 4 and Figure 5 ).

[0124] In more detail, the auxiliary ducts 34 , 35 are directly connected to the second section 30 b of the duct 30 .

[0125] Considering a cross section of the channel 22 passing through a plane orthogonal to the axis Z, the auxiliary ducts 34 and 35 are U-shaped and are arranged symmetrically relative to each other with respect to the median plane M ( Figure 5 ).

[0126] The extension of the cross section of each auxiliary duct 34, 35 is less than the minimum extension of the cross section of the duct 30. In addition, the sum of the maximum extensions of the cross sections of the auxiliary ducts 34 and 35 is lower than the minimum extension of the cross section of the duct 30.

[0127] like Figure 3 As shown, the openings 21 have a rectangular section in a plane orthogonal to the axis Z, are arranged parallel to each other and to the longitudinal axis Y, and are spaced apart from each other parallel to the axis X.

[0128] exist Figure 3 In the embodiment shown, containers 41, 42 and 43 each include:

[0129] - a cover 46;

[0130] - a base plate 47; and

[0131] A set of side walls 48 extending parallel to the axis Z between the cover 46 and the base plate 47 .

[0132] The lid 46, the base plate 47 and the set of side walls 48 of each container 41, 42 and 43 define an interior volume 50 of the associated container.

[0133] In particular, the opening 21 is obtained at the base plate 47 .

[0134] Preferably, the covers 46 are fixed to each other and to the pipes 31, 32 and 33 ( Figure 3 ).

[0135] Aircraft 1 also includes ( Figure 5 ):

[0136] a sensor device 65 suitable for detecting the temperature T of the battery 9 and operatively connected to the control unit 60 ;

[0137] A sensor device 70 adapted to detect the forward speed v of the aircraft 1 and operatively connected to the control unit 60 .

[0138] Preferably, the sensor device 70 comprises a flow meter adapted to detect a flow rate imparted to the aircraft 1 parallel to a horizontal or substantially horizontal forward direction of the aircraft 1 in use.

[0139] The cooling system 10 also comprises means (not shown) for varying the flow rate of air entering through the opening 20 .

[0140] Such a flow rate varying device comprises, for example, a valve which is suitable for partially restricting the flow rate of the incoming air and is operatively connected to the control unit 60 .

[0141] In detail, the control unit 60 is programmed to command a restriction of the flow of incoming air through the valve portion when the temperature T of the battery 9 is below 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.

[0142] The operation of the aircraft 1 according to the invention is described below.

[0143] In use, the aircraft 1 lands and takes off in the second configuration, with the rotor 4 arranged in the second position ( Figure 1B ). In this second configuration, the lift required to maintain the aircraft 1 is provided by the rotors 3a, 3b and 4.

[0144] During the transition from the first configuration to the second configuration of the aircraft, control unit 60 is programmed to reduce the thrust generated by rotors 3 a and 3 b as axes F, G of rotors 4 approach parallelism with axis Y and speed v of aircraft 1 increases.

[0145] The aircraft 1 moves forward at cruising speed in a first configuration, wherein the rotor 4 is arranged in a first position ( Figure 1A). In this first configuration, the lift required to maintain the aircraft 1 is provided in large part at least by the half-wing 8 and / or by other aerodynamic surfaces arranged along the aircraft 1. If necessary, the rotors 3a and 3b can be deactivated.

[0146] During use, the sensor device 65 detects the temperature T of the battery 9 and / or the sensor device 70 detects the forward speed v.

[0147] If the forward speed v is greater than the speed threshold v0 and / or the temperature T is less than the temperature threshold T0, the control unit 60 deactivates the fans 23 or keeps them deactivated.

[0148] In detail, when the fan 23 is deactivated, due to the movement of the aircraft 1, air enters the cooling system 10 through the opening 20, passes through the duct 30 and is distributed in the ducts 31, 32 and 33, thus reaching the containers 41, 42 and 43. In the internal volume 50 of the containers 41, 42 and 43, the air flows in the gap 45, absorbs the heat of the battery 9, and then escapes from the opening 21.

[0149] In more detail, during passage through the passage 22 , the air flow passes mainly through the second section 30 b and minimally through the auxiliary ducts 34 and 35 , due to the cross-sectional dimensions of these auxiliary ducts 34 , 35 relative to the cross-sectional dimensions of the second section 30 b .

[0150] On the contrary, if the forward speed v is lower than the speed threshold v0 (for example, when the aircraft 1 is hovering), or the temperature T exceeds the temperature threshold T0 , the control unit 60 activates the fan 23 .

[0151] In detail, when the fan 23 is working, the air passes through the same ducts through which the air passes when the fan 23 is deactivated. However, since the fan 23 is activated, the kinetic energy of the air increases and forced ventilation of the battery 9 is achieved.

[0152] If, during operation of the aircraft 1 , the temperature T of the battery 9 drops below a minimum temperature threshold Tmin, the control unit 60 commands a partial restriction of the incoming air flow. In this way, the heat removed from the battery 9 is reduced.

[0153] An examination of the characteristics of aircraft 1 shows the advantages it allows to obtain.

[0154] Since the cooling system 10 comprises a fan 23 which 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, it is possible to effectively regulate the temperature of the battery 9 of the aircraft 1. This is particularly true when the aircraft 1 is hovering and the flow of air entering through the opening 20 is therefore limited or in any case is characterized by low kinetic energy.

[0155] Since the opening 20 is arranged at the nose 5 , the flow rate of the air entering through the opening 20 itself can be maximized. At the same time, since the opening 21 is arranged at the belly 7 , the air flow leaving the cooling system 10 does not disturb the aerodynamics of the aircraft 1 .

[0156] Since the fans 23 are respectively arranged in the auxiliary ducts 34 , 35 , the fans 23 do not constitute an obstacle to the passage of air when they are deactivated, and the air passes through the duct 30 substantially without interference.

[0157] Obviously, the aircraft 1 described and illustrated herein may be subjected to modifications and variations without departing from the scope of protection defined by the claims.

[0158] The aircraft 1 may be a helicopter or a helicoplane.

[0159] At least some or all of the rotors 3a, 3b and 4 may have variable pitch.

[0160] The channel 22 may include a single auxiliary duct 34 , 35 or more than two auxiliary ducts 34 , 35 .

[0161] The cooling system 10 may comprise a single fan 23 or more than one fan 23. In particular, the cooling system 10 may comprise more than one fan 23 for each auxiliary duct 34,35.

[0162] The aircraft 1 may comprise one or two containers 41, 42, 43, or even more than three containers 41, 42, 43. Furthermore, the containers 41, 42, 43 cannot be aligned with each other.

[0163] The channel 22 may include a single conduit 30 that fluidly connects the opening 20 to a single container 41, 42 or 43. Preferably, the single conduit 30 fluidly connects the opening 20 directly to the single container 41, 42, 43. In other words, the channel 22 may not include conduits 31, 32, 33. According to this embodiment, one or more auxiliary conduits 34, 35 include respective first ends 34a, 35a and second ends 34b, 35b that each directly face the single conduit 30.

[0164] The direction K of the batteries 9 may be arranged parallel to the axis X, and the batteries 9 may be aligned with each other along the longitudinal axis Y. Additionally or alternatively, the openings 21 may be arranged parallel to each other and to the axis X, and spaced apart from each other parallel to the longitudinal axis Y.

[0165] The sensor devices 65 , 70 may be connected directly to the avionics equipment on board the aircraft 1 or may be connected to a control unit other than the control unit 60 .

Claims

1. An aircraft capable of hovering (1), comprising: - a fuselage (2) elongated along a longitudinal axis (Y); - at least one rotor (3a, 3b, 4) rotatable relative to the fuselage (2) about an axis of rotation; - electric drive means suitable for rotating said at least one rotor (3a, 3b, 4); - at least one battery (9) suitable for supplying power to the electric drive; as well as - a cooling system (10) for the at least one battery (9); The cooling system (10) comprises: - a first opening (20) suitable for allowing the entry of air; - a plurality of second openings (21) suitable for allowing air to escape; - a channel (22) fluidically connecting said first opening (20) with at least some of said second openings (21); The at least one battery (9) is placed within the channel (22) and fluidly interposed between the first opening (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23), the fan (23) being adapted to increase the kinetic energy of the air contained in the channel (22); In use, the fan (23) is 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 at least one battery (9) exceeds a temperature threshold (T0); The aircraft comprises at least one container (41, 42, 43) defining an internal volume (50), a plurality of batteries (9) being accommodated in the internal volume (50); the batteries (9) in the internal volume (50) defining a plurality of gaps (45) between each other and between the containers (41, 42, 43); Characterized in that the channel (22) comprises: - a first duct (30) extending from said first opening (20); - at least one second duct (31, 32, 33) branching from said first duct (30) and fluidically connecting said first duct (30) to the inner volume (50) of the respective container (41, 42, 43); and - said gap (45).

2. An aircraft according to claim 1, wherein the aircraft comprises at least two of the containers (41, 42, 43) defining respective internal volumes (50), and the channel (22) comprises at least two of the second ducts (31, 32, 33) branching from the first duct (30) and fluidically connecting the first duct (30) to the internal volumes (50) of the respective containers (41, 42, 43).

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

4. The aircraft according to claim 3, wherein 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); The first opening (20) is closer to the belly (7) than the second section (30b) along a first axis (Z) of the aircraft (1), the first axis (Z) being vertical in use and orthogonal to the longitudinal axis (Y).

5. An aircraft according to any one of the preceding claims, wherein the first duct (30) has a cross-section that decreases gradually along the longitudinal axis (Y) from the first opening (20).

6. An aircraft according to any one of the preceding claims, wherein the channel (22) further comprises at least one auxiliary duct (34, 35); Each of the auxiliary pipes (34, 35) includes a first end (34a, 35a) and a second end (34b, 35b) opposite to each other; The first end and the second end (34a, 35a; 34b, 35b) both directly face the first pipe (30); Each of the fans (23) is arranged at a corresponding auxiliary duct (34, 35).

7. An aircraft (1) capable of hovering, comprising: - a fuselage (2) elongated along a longitudinal axis (Y); - at least one rotor (3a, 3b, 4) rotatable relative to the fuselage (2) about an axis of rotation; - electric drive means suitable for rotating said at least one rotor (3a, 3b, 4); - at least one battery (9) suitable for supplying power to the electric drive; as well as - a cooling system (10) for the at least one battery (9); The cooling system (10) comprises: - a first opening (20) suitable for allowing the entry of air; - a plurality of second openings (21) suitable for allowing air to escape; - a channel (22) fluidically connecting said first opening (20) with at least some of said second openings (21); The at least one battery (9) is placed within the channel (22) and fluidly interposed between the first opening (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23), the fan (23) being adapted to increase the kinetic energy of the air contained in the channel (22); In use, the fan (23) is 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 at least one battery (9) exceeds a temperature threshold (T0); The aircraft comprises at least one container (41, 42, 43) defining an internal volume (50), wherein a plurality of batteries (9) are accommodated in the internal volume (50); the batteries (9) in the internal volume (50) define a plurality of gaps (45) between each other and between the containers (41, 42, 43); characterised in that the channel (22) comprises at least one conduit (30) fluidically connecting the first opening (20) to the at least one container (41, 42, 43); The channel (22) further comprises at least one auxiliary pipe (34, 35); Each of the auxiliary pipes (34, 35) includes a first end (34a, 35a) and a second end (34b, 35b) opposite to each other; The first end and the second end (34a, 35a; 34b, 35b) both directly face the pipe (30); Each of the fans (23) is arranged at a corresponding auxiliary duct (34, 35).

8. The aircraft according to claim 6 or 7, wherein the aircraft comprises two auxiliary ducts (34, 35) arranged symmetrically relative to each other with respect to a median plane (M) of the aircraft (1) parallel to the longitudinal axis (Y).

9. An aircraft according to any one of the preceding claims, wherein the aircraft comprises: - a control unit (60) operatively connected to said at least one fan (23); - a first sensor device (65) suitable for detecting the temperature of said at least one battery (9) and operatively connected to said control unit 60; and / or - a second sensor device (70) suitable for detecting the forward speed (v) of the aircraft (1) and operatively connected to the control unit (60).

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

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

12. An aircraft according to any one of the preceding claims, wherein the aircraft is a vertical take-off and landing aircraft, the vertical take-off and landing aircraft comprising: - said fuselage (2); - a pair of half-wings (8) arranged on respective mutually opposite portions of the fuselage (2) and having respective free ends opposite the fuselage (2) and aligned along a second axis transverse to the longitudinal axis (Y); as well as - at least a first pair of said rotors (4) rotatable about respective third axes (F, G) and tiltable relative to said half-wing (8) about a fourth axis (H) transverse to said longitudinal axis (Y).

13. The aircraft according to claim 12, wherein the aircraft further comprises: - a second pair of said rotors (3a) rotatable about respective fifth axes (B, C) fixed relative to said fuselage (2); as well as - a third pair of said rotors (3b) rotatable about respective sixth axes (D, E) fixed relative to said fuselage (2); The first pair of rotors (4) is interposed between the second pair of rotors (3a) and the third pair of rotors (3b) along the longitudinal axis (Y); Each rotor in the first pair of rotors (4), the second pair of rotors (3a) or the third pair of rotors (3b) can be operated independently of the other rotors in the first pair of rotors (4), the second pair of rotors (3a) or the third pair of rotors (3b).

14. A method for controlling an aerial vehicle (1) capable of hovering; the aerial vehicle comprising: - a fuselage (2) elongated along a longitudinal axis (Y); - at least one rotor (3a, 3b, 4) rotatable relative to the fuselage (2) about an axis of rotation; - electric drive means suitable for rotating said at least one rotor (3a, 3b, 4); - at least one battery (9) suitable for supplying power to the electric drive; as well as - a cooling system (10) for the at least one battery (9); The cooling system (10) comprises: - a first opening (20) suitable for allowing the entry of air; - a plurality of second openings (21) suitable for allowing air to escape; - a channel (22) fluidically connecting said first opening (20) with at least some of said second openings (21); The at least one battery (9) is placed within the channel (22) and fluidly interposed between the first opening (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23), the fan (23) being adapted to increase the kinetic energy of the air contained in the channel (22); The aircraft (1) further comprises at least one container (41, 42, 43) defining an internal volume (50), wherein a plurality of the batteries (9) are accommodated in the internal volume (50); the batteries (9) in the internal volume (50) define a plurality of gaps (45) between each other and between the containers (41, 42, 43); The channel (22) comprises: - a first duct (30) extending from said first opening (20); - at least one second duct (31, 32, 33) branching from said first duct (30) and fluidically connecting said first duct (30) to the inner volume (50) of the respective container (41, 42, 43); and - said gap (45); The method is characterized in that it comprises a step of operating the fan (23) 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).

15. A method according to claim 14, wherein the aircraft (1) comprises at least two of the containers (41, 42, 43) defining respective internal volumes (50), and the channel (22) comprises at least two of the second ducts (31, 32, 33) branching from the first duct (30) and fluidically connecting the first duct (30) to the internal volumes (50) of the respective containers (41, 42, 43).

16. A method for controlling an aerial vehicle (1) capable of hovering; the aerial vehicle comprising: - a fuselage (2) elongated along a longitudinal axis (Y); - at least one rotor (3a, 3b, 4) rotatable relative to the fuselage (2) about an axis of rotation; - electric drive means suitable for rotating said at least one rotor (3a, 3b, 4); - at least one battery (9) suitable for supplying power to the electric drive; as well as - a cooling system (10) for the at least one battery (9); The cooling system (10) comprises: - a first opening (20) suitable for allowing the entry of air; - a plurality of second openings (21) suitable for allowing air to escape; - a channel (22) fluidically connecting said first opening (20) with at least some of said second openings (21); The at least one battery (9) is placed within the channel (22) and fluidly interposed between the first opening (20) and at least some of the second openings (21); The cooling system (10) further comprises at least one fan (23), the fan (23) being adapted to increase the kinetic energy of the air contained in the channel (22); The aircraft (1) further comprises at least one container (41, 42, 43) defining an internal volume (50), wherein a plurality of the batteries (9) are accommodated in the internal volume (50); the batteries (9) in the internal volume (50) define a plurality of gaps (45) between each other and between the containers (41, 42, 43); The channel (22) comprises at least one conduit (30) fluidly connecting the first opening (20) to the at least one container (41, 42, 43); The channel (22) further comprises at least one auxiliary pipe (34, 35); Each of the auxiliary pipes (34, 35) includes a first end (34a, 35a) and a second end (34b, 35b) opposite to each other; The first end and the second end (34a, 35a; 34b, 35b) both directly face the pipe (30); Each of the fans (23) is arranged at a corresponding auxiliary duct (34, 35); The method is characterized in that it comprises a step of operating the fan (23) 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).

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