Hoverable aircraft

Abstract

Describes an aircraft (1) having a motor compartment (8); a motor system (6) having an exhaust pipe (17); a heat exchanger (20) disposed outside the motor system (6); a first air inlet (25); a first pipe (26) along which the heat exchanger (20) is disposed; a first convergent nozzle (15) having a downstream portion (39) fluidly connected to the exhaust pipe (17) and the first pipe (26) to form air having a first flow rate adapted to cool the heat exchanger (20); a second air inlet (10) opened in the motor compartment (8) and remote from the first air inlet (25); a second convergent nozzle (16) having a second downstream portion (49) fluidly connected to the exhaust pipe (17) and the motor compartment (8) to form a second flow rate of cooling air in the motor compartment (8) directed from the second air inlet (10) to the exhaust pipe (17) and bypassing the motor system (6).

Description

[0001] Cross - reference to related applications

[0002] This patent application claims the priority of Italian Patent Application No. 20171458.1, filed on April 27, 2020, the entire disclosure of which is incorporated herein by reference. Technical field

[0003] The present invention relates to an aircraft capable of hovering, in particular a helicopter or a thrust - reversing aircraft. Background art

[0004] Known helicopters basically include a fuselage, a main rotor rotatable about a first axis and arranged on top of the fuselage, and an anti - torque rotor arranged at the tail end of the helicopter and rotatable about a second axis transverse to the first axis.

[0005] Known types of helicopters also include a motor system and a transmission group for transmitting motion from the output shaft of the motor system to the main rotor.

[0006] More specifically, a motor system known in the art as a "turbo - shaft" generates an open thermodynamic cycle.

[0007] This motor system includes:

[0008] A support;

[0009] An air inlet adapted to allow air at a first flow rate to enter;

[0010] A compressor fluid - connected to the air inlet, which is supplied with the air at the first flow rate and is adapted to compress the air at the first flow rate;

[0011] A combustion chamber, in which the compressed air at the first flow rate from the compressor is mixed with fuel at a second flow rate and undergoes a combustion process to produce hot exhaust gas at a third flow rate; and

[0012] One or more turbines, in which the hot exhaust gas at the third flow rate leaving the combustion chamber expands by driving the compressor and the output shaft of the motor system to rotate independently of each other.

[0013] Each motor system also includes:

[0014] A convergent nozzle, which is arranged downstream of the corresponding turbine and is adapted to accelerate the exhaust gas at the third flow rate; and

[0015] An exhaust gas discharge pipe, which terminates at a corresponding opening of the support and in which the convergent nozzle is arranged.

[0016] Known types of helicopters also include a lubrication system, which is adapted to allow lubrication of the motor system and help cool the motor system itself.

[0017] More specifically, the lubrication system includes:

[0018] A collection tank for a lubricating fluid (such as oil); and

[0019] A distribution circuit configured to distribute the lubricating fluid into specific areas of the motor system and to allow the lubricating fluid to return to the tank.

[0020] During the cycle, the lubricating fluid comes into contact with the moving parts of the motor system and thus increases its temperature.

[0021] In order to prevent the lubricating fluid from getting too hot, the lubrication system in known solutions includes:

[0022] A fan adapted to generate a fourth fresh air flow; and

[0023] A heat exchanger that allows the lubricating fluid to be cooled by exchanging heat with the fourth air flow generated by the fan.

[0024] Using a fan or a similar active system causes an increase in the weight of the helicopter.

[0025] Starting the fan or a similar active system also requires a certain ratio of power that is taken directly electrically from the on-board system or mechanically through the motor system and subtracted from the actual mechanical power value available from the motor shaft.

[0026] The fan and the associated drive group also require corresponding accommodation within the helicopter, which sometimes creates problems of integration with other systems and / or the structure and shape of the airframe itself.

[0027] Finally, the fan and the associated drive group inevitably have a risk of failure, thus deteriorating the overall reliability of the motor system of the helicopter. These known types of solutions also require more frequent inspection and maintenance cycles, thus increasing the overall operating cost of the helicopter.

[0028] WO-A-2003 / 037715 describes a passive cooling system for an auxiliary power unit of an aircraft.

[0029] The auxiliary power unit is designed to supply electrical power and compressed air to a plurality of systems on board the aircraft.

[0030] The auxiliary power unit is essentially a gas turbine system equipped with a pair of compressors housed in a nacelle.

[0031] The auxiliary power unit also includes a heat exchanger for cooling the lubricating fluid.

[0032] The gas turbine includes, in a known manner, an additional discharge duct for the exhaust gas mixture housed in the nacelle.

[0033] In the first embodiment, the nacelle defines:

[0034] a single air inlet for supplying an air flow to a compressor and a heat exchanger; and

[0035] an outlet of a further exhaust duct of the gas turbine.

[0036] The nacelle further houses:

[0037] a first duct disposed downstream of the single air inlet; and

[0038] a second duct and a third duct defining respective branches of the first duct.

[0039] More particularly, the second duct extends between the first duct and a first suction port of one of the compressors.

[0040] The third duct in turn branches into a first part and a second part disposed downstream of the first duct.

[0041] The first part fluidly connects the first duct to a second suction port of the other compressor.

[0042] The second part fluidly connects the first duct and is disposed within the internal volume of the nacelle. The heat exchanger is disposed along the second part.

[0043] The further exhaust duct of the gas turbine has a convergent nozzle including a gradually decreasing area. The nozzle in turn has a downstream part fluidly connected to the internal volume downstream of the second part of the nacelle.

[0044] In this way, the exhaust gas flow in the exhaust duct causes a decrease in the velocity of the exhaust gas and a consequent pressure drop at the downstream part of the nozzle and thus in the nacelle region located downstream of the second part.

[0045] The pressure drop causes a first air flow to pass through the heat exchanger and a second air flow to be directed towards the first and second suction ports of the compressor.

[0046] In other words, the nozzle defines an ejector at its downstream part.

[0047] Since the second part opens into the volume of the nacelle, the first air flow cools both the heat exchanger and the internal volume of the nacelle.

[0048] Thus, the cooling of the heat exchanger and the cooling of the internal volume of the nacelle cannot be controlled independently.

[0049] WO-A-2003 / 037715 describes other embodiments in each of which a cooling air flow of the internal volume of the nacelle is driven by an ejector into the exhaust duct of the motor system.

[0050] Thus, the same air flow cools both the heat exchanger and the interior volume of the nacelle.

[0051] There is a need in the art to independently and optimally control the cooling of the housing of the motor system and the heat exchanger.

[0052] The purpose of this is to optimize the cooling of the nacelle of the motor system and the heat exchanger in terms of size and function. Summary of the Invention

[0053] The object of the present invention is to implement an aircraft capable of hovering, which allows the above needs to be met in a simple and economical manner. Brief Description of the Drawings

[0054] To better understand the present invention, the preferred embodiments will be described below by way of non-limiting examples and with reference to the drawings, in which:

[0055] Figure 1 A perspective view of a helicopter according to the present invention is shown;

[0056] Figure 2 is Figure 1 An extremely enlarged view from above of the helicopter and the associated motor system, which is extremely enlarged and some parts are removed for clarity;

[0057] Figure 3 is Figure 1 and 2 A further enlarged front perspective view of some components of the motor system of the helicopter according to a first perspective;

[0058] Figure 4 is Figure 3 An exploded view of the components of the motor system;

[0059] Figure 5 is Figure 3 and 4 A further enlarged rear perspective view of the components of the motor system according to another perspective relative to Figure 3 ;

[0060] Figure 6 and 7 show Figures 3 - 5 A further enlarged perspective view of the components, with some parts removed for clarity;

[0061] Figure 8 is Figures 3 - 7 A rear view of the components of the motor system;

[0062] Figure 9 show Figures 1 - 8 An exploded view of the components of the motor system;

[0063] Figure 10 and 11 respectively show a top view and a perspective view of components of the motor system of Figures 3 - 9 ;

[0064] Figure 12 is Figures 1 - 11 a front view of additional components of the motor system of

[0065] Figure 13 shows Figure 12 another embodiment of additional components of ; and

[0066] Figure 14 shows Figure 13 another embodiment of additional components of Detailed Embodiment

[0067] Referring to Figure 1 , reference numeral 1 denotes a helicopter which basically comprises a fuselage 2 provided with a front head 5, a main rotor 3 provided at the top of the fuselage 2 and rotatable about a first axis, and a tail rotor 4 carried by an offset portion protruding from the fuselage 2 on opposite sides of the head 5 and rotatable about a second axis transverse to the first axis.

[0068] It should be noted that in the following part of this specification, expressions such as "upper", "lower", "front", "rear", etc. are used with reference to Figure 1 the forward flight or "hovering" state of the helicopter 1 shown, and wherein the main rotor 3 is provided above the fuselage 2 and the head 5 is provided in front of the tail rotor 4.

[0069] The helicopter 1 includes a motor system 6 housed in a motor compartment 8 defined by a support 7.

[0070] The motor compartment 8 is in fluid connection with an air inlet 10 adapted to allow a cooling air flow to enter the motor compartment 8 itself.

[0071] The helicopter 1 further includes a transmission group (not shown as it is known per se and not part of the present invention) adapted to connect an output shaft (also not shown) of the motor system 6 to a shaft for driving the main rotor 3 rotatable about axis A.

[0072] The motor system 6 is embodied as a gas turbine device implementing an open Joule - Brayton thermodynamic cycle.

[0073] The motor system 6 basically comprises ( Figure 2 ):

[0074] an air inlet 9 formed in a side portion of the fuselage 2 through which low - temperature air at a first flow rate is sucked into the motor compartment 8;

[0075] A compressor 11 (only schematically shown), which is provided with an air intake pipe (not shown) for air at a first flow rate that is fluidly connected to the air inlet 9 and is adapted to compress the air at the first flow rate;

[0076] A combustion chamber 13 (only schematically shown), in which the air at the first flow rate compressed by the compressor 11 reacts with fuel at a second flow rate to generate hot exhaust gas at a third flow rate; and

[0077] A pair of turbines 14 (only schematically shown), in which the hot exhaust gas at the third flow rate leaving the combustion chamber 13 expands to drive the compressor 11 and the output shaft to rotate.

[0078] In particular, the compressor 11, the turbine 14, and the output shaft are rotatable about an axis A.

[0079] The air inlet 9 is arranged transversely to the axis A and is different from the air inlet 10.

[0080] The motor system 6 further includes a pipe 17 for discharging the hot exhaust gas at the third flow rate, which terminates at a corresponding opening 18 of the support 7.

[0081] The helicopter 1 further includes a lubrication system (which is known per se and thus not shown in detail), which is adapted to allow lubrication and assist in cooling the motor system 6.

[0082] More specifically, the lubrication system includes a collection tank (not shown) for the lubricating fluid, a distribution circuit (not shown) configured to distribute the lubricating fluid to specific areas of the motor system 6 and allow the lubricating fluid to return to the tank.

[0083] During the cycle, the lubricating fluid contacts the moving parts of the motor system 6 and raises its temperature.

[0084] The lubrication system further includes a heat exchanger 20, which allows the lubricating fluid to be cooled by exchanging heat with an air flow.

[0085] In other words, the heat exchanger 20 is a radiator through which the lubricating fluid passes and is cooled by an air flow.

[0086] The heat exchanger 20 is arranged outside the motor system 6.

[0087] The helicopter 1 further includes:

[0088] An additional air inlet 25, which opens on the side of the fuselage 2 and is adapted to suck in air at a fourth flow rate; and

[0089] A pipe 26, along which the heat exchanger 20 is arranged and through which the air at the fourth flow rate flows.

[0090] The air inlet 25 is different from the air inlet 10.

[0091] The duct 26 further comprises:

[0092] An inlet portion 27 that extends between the air inlet 25 and the heat exchanger 20; and

[0093] A pair of channels 28 ( Figure 2 , 4 and 7 - 10), which extend from the heat exchanger 20 and are disposed on opposite sides of the portion 27 with respect to the heat exchanger 20.

[0094] The helicopter 1 further comprises a convergent nozzle 15, which is disposed downstream of the turbine 14 and is traversed by the exhaust gas at a third flow rate.

[0095] The nozzle 15 has a tubular shape with an axis A and comprises:

[0096] A surface 31 that is radially inside the axis A and is shaped as a tapered cone and extends from the turbine 14 towards the discharge pipe 17; and

[0097] A plurality of vanes 32 that are equally angularly spaced around the axis A and project towards the axis A itself in a cantilever manner from the surface 31.

[0098] The nozzle 15 comprises ( Figure 3 , 4 and 6 - 9):

[0099] An upstream portion 38 that is in fluid connection with the turbine 14; and

[0100] A downstream portion 39 that is opposite to the upstream portion 38 and is disposed on the side of the discharge pipe 17.

[0101] The downstream portion 39 of the nozzle 15 is in fluid connection with the channels 28 of the duct 26 and the discharge pipe 17.

[0102] Referring to Figure 2 , the helicopter 1 comprises an ejector 80 formed by the downstream portion 39 of the nozzle 15 and the channels 28 of the duct 26.

[0103] The term "ejector" or "ejector pump" in this specification refers to a pump formed by a convergent nozzle, in which a main flow of fluid is conveyed and has a downstream portion that is in fluid connection with a duct. The convergent shape of the nozzle causes the static pressure to decrease in the downstream portion of the nozzle, which allows a secondary flow to be suctioned through the duct. The main flow and the secondary flow are mixed in the outlet portion of the nozzle.

[0104] The channels 28 include corresponding openings 43 that are opposite to the heat exchanger 20 and open at the downstream portion 39 of the nozzle 15 ( Figure 8 ).

[0105] More precisely, the nozzle 15 causes the static pressure of the exhaust gas of the third flow rate leaving the turbine 14 to decrease at the downstream portion 39. The decrease in the static pressure causes the air of the fourth flow rate for cooling the heat exchanger 20 to pass through the duct 26 and mix with the exhaust gas of the third flow rate in the downstream portion, thereby generating the exhaust gas and air of the fifth flow rate through the downstream portion 39.

[0106] The nozzle 15 is partially received within the nozzle 16 and is disposed upstream of the discharge pipe 17.

[0107] The downstream portion 39 of the nozzle 15 is in fluid communication with the passage 28.

[0108] Advantageously, the helicopter 1 includes additional convergent nozzles 16 ( Figures 2 - 7 and 9-11) and has a downstream portion 49 that is in fluid communication with the discharge pipe 17 and the motor compartment 8, thereby generating a sixth flow rate of cooling air for the motor compartment 8 itself that is directed from the air inlet 10 towards the discharge pipe 17 and bypasses the motor system 6.

[0109] The air of the sixth flow rate cools the motor compartment 8.

[0110] More specifically, the nozzle 16 includes an upstream portion 48 that faces the downstream portion 49 and is in fluid communication with the downstream portion 39 of the nozzle 15.

[0111] The downstream portion 49 is in fluid communication with the motor compartment 8, which will be described in more detail below.

[0112] The helicopter 1 includes an additional ejector 90 formed by the nozzle 16 and the motor compartment 8.

[0113] More precisely, the nozzle 16 causes the static pressure of the air and exhaust gas of the fifth flow rate to decrease at the downstream portion 49. The decrease in the static pressure causes the air of the sixth flow rate for cooling the motor compartment 8 itself to pass through the motor compartment 8 and mix with the exhaust gas and air of the fifth flow rate in the downstream portion 49, thereby generating the exhaust gas and air of the seventh flow rate through the downstream portion 49.

[0114] Referring to Figures 3 - 11 , the nozzle 15 is disposed upstream of the nozzle 16 and extends from the turbine 14 towards the discharge pipe 17.

[0115] The nozzles 15, 16 are coaxially disposed with respect to the axis A.

[0116] The nozzle 15 is partially received within the nozzle 16 and is disposed upstream of the discharge pipe 17.

[0117] The nozzle 15 is also radially spaced apart from the nozzle 16.

[0118] Referring to Figures 3 - 8, 10, and 11, the helicopter 1 further includes a support 40 that supports the heat exchanger 20.

[0119] The support 40 generally defines the passage 28 and the nozzle 16 and houses the nozzle 15.

[0120] More specifically, the support 40 generally includes, from the turbine 14 toward the discharge pipe 17:

[0121] a portion 44 that projects relative to the axis A and houses the nozzle 15 therein and defines the passage 28 of the duct 16; and

[0122] a tubular portion 45 that is partially housed within the portion 44 and partially housed within the discharge pipe 17 relative to the axis A and, together with it, defines the nozzle 16.

[0123] The portion 44 supports the heat exchanger 20 and defines the passage 28.

[0124] In particular, the portion 44 includes:

[0125] a disc-shaped wall 46 that is orthogonal to the axis A and bounds the support 40 on the side of the turbine 14; and

[0126] an arcuate wall 47 that projects from the radially axis-A-opposite end edge 70 of the wall 46 toward the discharge pipe 17 in a cantilever manner.

[0127] The walls 44, 47 surround the lower portion 45 and open above the portion 45.

[0128] The wall 46 also includes an end edge 72 that is radially inside and opposite the end edge 70. The nozzle 15 is circumferentially fixed to the end edge 72 ( Figure 7 ).

[0129] The wall 46 also includes an upper end portion 41 that is straight and orthogonal to the axis A and is closed below the portion 45.

[0130] The wall 47 includes a pair of upper end portions 42 that are parallel to the axis A and are connected to the end portion 41. The wall 47 is also closed below the portion 45.

[0131] The support 40 also includes ( Figure 7 ):

[0132] a pair of walls 50 facing corresponding portions 51 ( Figure 8 ) of the corresponding wall 47; and

[0133] a wall 52 axially opposite the wall 46.

[0134] The walls 47, 50 extend at a position axially interposed between the walls 46, 52.

[0135] The walls 47, 50 extend symmetrically with respect to an axis B which is orthogonal to the axis A and is vertically arranged in use.

[0136] More precisely, each wall 50 comprises:

[0137] An end 57 fixed to the heat exchanger 20;

[0138] A free end 59 opposite to the corresponding end 57.

[0139] Each wall 52 further comprises an end 58 which fixes the heat exchanger 20 and is connected to the corresponding end 57.

[0140] The wall 50 defines free and spaced-apart diverging tips extending from the corresponding common end 57 towards the corresponding end 59 ( Figure 8 ).

[0141] The support 40 defines a ( Figure 4 ) peripheral end edge 60 which is open and fixed to the heat exchanger 20.

[0142] The edge 60 is defined by the end 41 of the wall 46 and the end 58 of the wall 57 via corresponding portions which are axially opposite to each other.

[0143] The edge 60 is also defined by the end 42 of the wall 47.

[0144] The edge 60 is rectangular in the example shown.

[0145] The end 57 of the wall 50 is arranged parallel to the end 42 and spans the edge 60.

[0146] More particularly, the end 57 of the wall 50 divides the edge 60 into two identical regions which define corresponding inlet portions of the corresponding channels 28 opposite to the corresponding openings 43.

[0147] The ends 41, 58 are axially opposite to each other.

[0148] The ends 42, 57 are opposite to each other and are axially interposed between the ends 41, 42.

[0149] Referring to Figure 8 , each opening 43 is axially defined by the end 59 of the corresponding wall 50 and the end of the corresponding wall 52 opposite to the end 58.

[0150] The channel 28 has a gradually decreasing thickness in a direction orthogonal to the corresponding wall 50 from the end 57 towards the corresponding end 59, i.e., from the heat exchanger 20 towards the corresponding opening 43.

[0151] The part 45 from the turbine 14 towards the discharge pipe 17 includes( Figure 6 , 8 and 11):

[0152] a wall 65 surrounding the nozzle 15; and

[0153] a wall 66 which is axially offset from the nozzle 15 and is provided with a plurality of vanes 67 projecting towards the axis A in a cantilever manner from the radial inner surface 69 of the wall 66 itself and a plurality of through openings 68.

[0154] In particular, with reference to Figure 8 , the wall 65 is shaped as an arc coaxial with the axis A.

[0155] The wall 65 extends between the ends 59 of the corresponding wall 51.

[0156] The wall 65 surrounds an arcuate portion of the corresponding angular width of the nozzle 15.

[0157] In the example shown, the wall 65 extends across an arc of approximately 90 degrees and extends symmetrically with respect to an axis B which is orthogonal to the axis A and is vertically arranged in the conventional flight configuration of the helicopter 1.

[0158] The wall 66 is embedded in the wall 52.

[0159] The vanes 67 are equally angularly spaced about the axis A and are arranged at the corresponding vanes 32 of the nozzle 15 and extend parallel to the axis A.

[0160] The openings 68 are equally angularly spaced about the axis A and elongate along the axis A.

[0161] Each opening 68 is associated with a corresponding vane 67.

[0162] The vanes 67 project from the wall 66 in a cantilever manner at the corresponding openings 68.

[0163] The wall 66 is partially received within the discharge pipe 17.

[0164] More particularly, the discharge pipe 17 includes an annular end 71 opposite the opening 18. The end 71 together with the wall 65 which is axially opposite the wall 46 defines an annular groove 81.

[0165] In particular, the discharge pipe 17 has a portion 73 converging with respect to the axis A, a portion 74 having a constant diameter, and a portion 75 diverging with respect to the axis A from the end 71 towards the opening 18.

[0166] The groove 81 and the openings 68 fluidly connect the motor compartment 8 with the downstream portion 49 of the nozzle 16.

[0167] The wall 66 includes an annular end 82 which is axially opposite to the wall 46, is received within the discharge pipe 17 and is radially spaced apart from the discharge pipe 17.

[0168] In particular ( Figure 12 ), the portion 44 extends symmetrically with respect to an axis B which is orthogonal to the axis A and is disposed above the axis A with respect to the conventional operating configuration of the helicopter 1. The air inlet 25 is disposed below the main rotor 3. In this way, the downwash generated by the main rotor 3 generates a dynamic flow within the air inlet 25, which further helps to cool the heat exchanger 20.

[0169] According to Figure 13 the alternative embodiment shown, the portion 44 extends symmetrically with respect to an axis C which is inclined with respect to the axis A and is disposed above the axis A with respect to the conventional operating configuration of the helicopter 1.

[0170] According to Figure 14 the alternative embodiment shown, the portion 44 extends symmetrically with respect to an axis D which is inclined with respect to the axis A and is disposed below the axis A with respect to the conventional operating configuration of the helicopter 1.

[0171] The support 40 further includes a heat dissipation device 100 which is arranged to protect the heat exchanger 20 from possible damage by the heat conveyed by the motor system 6.

[0172] More specifically, the device 100 includes ( Figure 7 ):

[0173] a grid 101 applied to the wall 65 at a position radially interposed between the heat exchanger 20 and the nozzle 15; and

[0174] a grid 102 interposed between the wall 66 and the wall 52.

[0175] In particular, the grid 101 is shaped as a circular arc symmetrical with respect to the axis A and has a lower corner extension of the wall 65.

[0176] The grid 101 is disposed below the wall 50.

[0177] The grid 102 extends obliquely with respect to the axis A.

[0178] The helicopter 1 further includes a device for protecting the heat exchanger 20 against possible "heat shock" which would temporarily overheat the oil in the heat exchanger 20. The overheating may occur due to hot gas which thus tends to stagnate slightly in the nozzle 15 or along the discharge pipe 17 when the motor system 6 is deactivated. Another situation where unexpected overheating of the heat exchanger 20 may occur is the presence of a flame within the passage 28, for example due to a malfunction of the motor system 6 and / or a fire in the motor compartment 8.

[0179] More specifically, the device 55 can be selectively moved between the following configurations:

[0180] An open configuration, in which it allows a fluid connection between the heat exchanger 20 and the discharge pipe 17; and

[0181] A closed configuration, in which it interrupts the fluid connection passing between the heat exchanger 20 and the discharge pipe 17.

[0182] More precisely, the device 55 is set in the open configuration during the normal operation of the motor system 6 and / or in the absence of a flame in the passage 28.

[0183] Conversely, the device 55 is set in the closed configuration when the motor system 6 is deactivated or when there is a flame in the passage 28.

[0184] In one embodiment of the present invention, the device 55 can be reversibly moved from the open configuration to the closed configuration by a passive system (such as an elastic element, a shape memory metal alloy, etc.) or an active system (such as an elastic, hydraulic or pneumatic actuator or a suitable combination of the principles described herein).

[0185] The helicopter 1 further includes:

[0186] A sensor 54 (only schematically shown in Figure 8 ), which is adapted to detect the deactivation of the motor system 6 and / or the presence of a flame in the passage 28; and

[0187] An actuator (not shown), which is controlled by the sensor and is adapted to move the device 55 between the open configuration and the closed configuration according to what is detected by the sensor.

[0188] In Figure 8 the example shown, the device 55 is formed by walls 50, which are hinged to the support 40 around a common axis parallel to the axis A and coincide with the common end 57 of the corresponding walls 50.

[0189] The end 59 opens the corresponding opening 43 when the device 55 is in the closed configuration and opens the said opening 43 when the device 55 is in the open configuration.

[0190] In use, air at a first flow rate is inhaled from the air inlet 9 and passes through the intake pipe to the compressor 11 of the motor system 6.

[0191] The air inlet 10 allows an air flow to enter the motor compartment 8.

[0192] The air at the first flow rate is compressed in the compressor 11 and reacts with fuel at a second flow rate in the combustion chamber 13 to produce exhaust gas and air at a third flow rate at high temperature and high pressure.

[0193] Subsequently, the exhaust gas and air at the third flow rate expand into the turbine 14 by driving the compressor 11 and the output shaft to rotate about the axis A.

[0194] The third flow rate further expands into the nozzle 15 by reducing its static pressure at the downstream portion 39.

[0195] This reduced static pressure at the downstream portion 39 causes air at the fourth flow rate to be drawn in through the air inlet 25 and the duct 26. The fourth flow rate reaches the opening 43 of the passage 28 that is fluidly connected to the downstream portion 39 of the nozzle 15.

[0196] The air at the fourth flow rate passes through the heat exchanger 20 to cool it and mixes with the third flow rate in the downstream portion 39 of the nozzle 15, thereby forming a fifth flow rate.

[0197] The exhaust gas and air at the fifth flow rate further expand in the nozzle 16, thereby reducing its own static pressure at the downstream portion 39 of the nozzle 16 itself.

[0198] By means of this reduction in static pressure, the ejector 90 generates low-pressure air at the sixth flow rate within the motor compartment 8 and passing through the air inlet 10 at the downstream portion 49.

[0199] The air at the sixth flow rate bypasses the compressor 11, the combustion chamber 13, and the turbine 14, and cools the motor compartment 8.

[0200] The air at the sixth flow rate flows from the motor compartment 8 to the downstream portion 49 through the slot 81 and the opening 68 of the portion 45, thereby cooling the motor compartment 8( Figure 2 )

[0201] The air at the sixth flow rate mixes with the air at the fifth flow rate at the downstream portion 49, thereby forming air at the seventh flow rate.

[0202] The air at the seventh flow rate passes through the discharge pipe 17 until it reaches the opening 18, and is discharged into the atmosphere through the opening 18.

[0203] The device 55 is set to an open configuration during the normal operation of the motor system 6 and / or when there is no flame in the passage 28.

[0204] In the open configuration, the device 55 does not interfere with the flow of the air current in the passage 28.

[0205] If the sensor 54 confirms that the motor system 6 is deactivated or there is a flame in the passage 28, the device 55 is set to a closed configuration, for example, by means of a relevant actuator (such as by rotating the wall 50 about a common axis for hinging to the support 40).

[0206] In the closed configuration, device 55 prevents the flame from passing through passage 28 and returning towards heat exchanger 20, thus maintaining their integrity.

[0207] Device 100 helps dissipate the heat generated by motor system 6 preferably located within motor compartment 8, further contributing to maintaining the integrity of heat exchanger 20.

[0208] More specifically, the air heated by motor system 6 rises within nozzle 15 until it reaches grids 101, 102, which allows it to escape and be processed.

[0209] By examining the characteristics of helicopter 1 formed according to the present invention, the advantages that can be obtained are obvious.

[0210] In particular, the downstream portion 39 of nozzle 15 is in fluid connection with heat exchanger 20 and the downstream portion 49 of nozzle 16 is in fluid connection with motor compartment 8.

[0211] Thus, injector 80 generates a fourth flow rate of air that passes through and cools heat exchanger 20.

[0212] Injector 90 generates a sixth flow rate of air that passes through and cools motor compartment 8.

[0213] Since the air at the fourth and sixth flow rates passes through different paths upstream of discharge pipe 17 respectively, the cooling of heat exchanger 20 and the cooling of motor compartment 8 can be controlled independently, unlike the known type of solutions described in the background art section of this specification.

[0214] Therefore, the temperature of motor system 6 and / or the temperature of motor compartment 8 can be controlled more precisely and accurately without installing additional devices, as can be seen in the known type of solutions described in the background art section of this specification, where installing additional devices complicates the maintenance of helicopter 1 and increases the total weight of the helicopter.

[0215] Blade 67 defines an extension of nozzles 15, 16. In particular, blade 67 enables the interaction between nozzle 15 and nozzle 16 in terms of hydrodynamics.

[0216] In fact, as described above, blade 67 is preferably arranged at the corresponding blade 32 of nozzle 15 and extends parallel to axis A.

[0217] By means of this, the turbulence and hydrodynamic losses caused by the air and exhaust gas flowing within the corresponding nozzles 15, 16 at the third and fifth flow rates can be reduced.

[0218] Device 100 allows the dissipation of the heat generated by the operation of motor system 6 within motor compartment 8, reducing the risk of damaging heat exchanger 20.

[0219] Heat dissipation by convection is more efficient by positioning the grid 101 above the motor system 6. Due to this position, the "hot" air present in the motor system 6 (and thus the lower density air present in the motor compartment 8) naturally tends to move towards the grids 101, 102 and away from the heat exchanger 20.

[0220] The device 55 can be selectively moved between the following configurations:

[0221] An open configuration, in which it allows fluid connection between the heat exchanger 20 and the discharge pipe 17 through the passage 28; and

[0222] A closed configuration, in which the fluid connection between the heat exchanger 20 and the discharge pipe 17 through the passage 28 is interrupted.

[0223] In this way, as hot air stagnates in the passage 28 when the motor system 6 is deactivated in the presence of an open flame, the risk of damaging the heat exchanger 20 can be further reduced.

[0224] By attaching Figure 12 the features in, the part 44 extends symmetrically with respect to an axis B orthogonal to the axis A and is disposed above the axis A. Thus, the fresh air flow entering through the air intake 25 benefits from the dynamic flow generated by the downward and air intake 25 - directed air flow generated by the main rotor 3. The dynamic flow has the same magnitude as the fourth flow rate and the sixth flow rate respectively generated by the heat exchanger 20 and the motor compartment 8 via the ejectors 80, 90.

[0225] With particular reference to Figure 13 , the part 44 extends symmetrically with respect to an axis C inclined with respect to the axis A. In this case, the contribution of the above - mentioned dynamic flow is less than Figure 12 the configuration of and the main part of the fourth flow rate and the sixth flow rate respectively generated by the ejectors 80, 90 through the heat exchanger 20 and the motor compartment 8.

[0226] Referring to Figure 14 , the part 44 extends symmetrically with respect to an axis D inclined with respect to the axis A and disposed below the axis A with respect to the conventional operating configuration of the helicopter 1.

[0227] In the said configuration, the dynamic contribution of the rotor 3 is almost negligible. Thus, the intake of the air of the fourth flow rate and the air of the sixth flow rate is effectively achieved only through the respective ejectors 80, 90.

[0228] Finally, it is obvious that modifications and variations can be made to the above - mentioned helicopter 1 without thereby departing from the scope of protection of the present invention.

[0229] In particular, the helicopter 1 may include a pair of motor systems 6 having respective output shafts operatively connected to the main rotor 3.

[0230] The hovering aircraft can be a thrust-reversing aircraft rather than a helicopter1.

Claims

1. An aircraft (1) capable of hovering, comprising: A motor compartment (8); A motor system (6), which is partially accommodated in the motor compartment (8) and further includes an exhaust pipe (17) that at least partially extends outside the motor compartment (8); A heat exchanger (20), which is arranged outside the motor system (6); A first air inlet (25), which is fluidly connected to the heat exchanger (20); A first pipe (26), which extends between the first air inlet (25) and the exhaust pipe (17), and the heat exchanger (20) is arranged along the first pipe; A first convergent nozzle (15), which has a first downstream portion (39) fluidly connected to the exhaust pipe (17) and the first pipe (26) to form air with a first flow rate suitable for cooling the heat exchanger (20) and passing through the first pipe (26) during use; And A second air inlet (10), which opens in the motor compartment (8) and is away from the first air inlet (25), Characterized in that the aircraft includes a second convergent nozzle (16), which has a second downstream portion (49) fluidly connected to the exhaust pipe (17) and the motor compartment (8) to form a second flow rate of cooling air in the motor compartment (8) that points from the second air inlet (10) to the exhaust pipe (17) and bypasses the motor system (6).

2. The aircraft according to claim 1, wherein The first convergent nozzle (15) and the second convergent nozzle (16) are coaxial with each other.

3. The aircraft according to claim 1 or 2, characterized in that The first convergent nozzle (15) is at least partially accommodated in the second convergent nozzle (16).

4. The aircraft according to claim 3, characterized in that, It includes a first annular opening (81), which is inserted between the second downstream portion (49) and the exhaust pipe (17) and is in fluid communication with the motor compartment to define a first passage path for the second flow rate of cooling air.

5. The aircraft according to claim 4, characterized in that, It includes a plurality of second openings (68), which pass through the second convergent nozzle (16) and are in fluid connection with the motor compartment (8) to define a second passage path for the second flow rate of cooling air.

6. The aircraft according to claim 5, characterized in that, The first convergent nozzle (15) includes a plurality of first vanes (32) that interact with the air with the first flow rate during use, The second convergent nozzle (16) includes a plurality of second vanes (67) that interact with the second flow rate of cooling air during use and define corresponding extensions of the corresponding first vanes (32).

7. The aircraft according to claim 6, characterized in that, Each of the second vanes (67) is arranged at a corresponding one of the second openings (68).

8. The aircraft according to claim 1, wherein It includes a single support body (40), which defines the second convergent nozzle (16) and the heat exchanger (20) is fixed thereon, The single support body (40) further defines at least one passage (28) of the first pipe (26) that is opposite to the heat exchanger (20) relative to the second air inlet (10).

9. The aircraft according to claim 8, wherein, The single support body (40) includes: A first wall (46), which defines the second convergent nozzle (16); and A pair of channels (28), the pair of channels at least partially surrounding the first convergent nozzle (15) and being in fluid communication with the heat exchanger (20). The channels (28) are in fluid communication with the first downstream portion (39) at their openings (43) opposite the heat exchanger (20).

10. The aircraft according to claim 9, characterized in that, The support (40) includes a pair of second walls (50) transverse to the first wall (46), the second walls defining respective ones of the channels (28) that extend from the heat exchanger (20) and are interrupted at respective ones of the openings (43).

11. The aircraft according to any one of claims 8-10, characterized in that, The support (40) includes heat dissipation means (100, 101, 102) that open towards the motor compartment (8) and are thermally coupled to at least one of the first convergent nozzle (15) and the second convergent nozzle (16), thereby inhibiting heat transfer from the motor system (6) to the heat exchanger (20).

12. The aircraft according to claim 10, characterized in that, It includes: A sensor (54) adapted to detect the deactivation of the motor system (6) and / or the presence of a flame in one of the channels (28); and The second wall (50) that selectively moves between the following configurations based on the detection by the sensor (54): An open configuration, in which the second wall allows fluid connection between the heat exchanger (20) and the discharge pipe (17) through the channel (28); And A closed configuration, in which the second wall interrupts the fluid connection between the heat exchanger (20) and the discharge pipe (17) through the channel (28).

13. The aircraft according to claim 1, characterized in that, The heat exchanger (20) is a radiator adapted to cool a liquid that lubricates the motor system (6) in use.

14. The aircraft according to claim 1, characterized in that The motor system (6) includes: A third air inlet (9) that is different from the first air inlet (25) and the second air inlet (10); A compressor (11) that sucks in air at a third flow rate from the third air inlet (9) in use; A combustion chamber (13) that receives the compressed third flow rate of air from the compressor (11) in use to provide a fourth flow rate of air and exhaust gas at an outlet in use; At least one turbine (14) adapted to expand the fourth flow rate of air and exhaust gas in use, The first convergent nozzle (15) supplies the fourth flow rate through the at least one turbine (14) in use, The second convergent nozzle (16) supplies the fourth flow rate and the first flow rate through the first convergent nozzle (15) in use and provides a fifth flow rate at an outlet, The second convergent nozzle (16) supplies the fifth flow rate and the second flow rate through the first convergent nozzle (15) in use and provides a sixth flow rate at an outlet, and The discharge pipe (17) supplies the sixth flow rate through the second convergent nozzle (16) in use.

15. The aircraft according to claim 1, characterized in that It is a helicopter or a thrust-reversing aircraft; and / or It is characterized in that it includes a main rotor (3) provided above the first air inlet (25) to generate an air flow through the first duct (26) in use.

Images