Indicator for an aircraft capable of hovering and method for assisting in performing operations of said aircraft

Abstract

The invention discloses an indicator (16a) for an aircraft (1) capable of hovering, comprising a first indication (35) associated with a vertical speed value of the aircraft (1) itself; the indicator (16a) comprises a first area (100) in which a second indication (102) associated with a situation in which a vortex ring state is reached can be displayed.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority from European patent application No. 20216228.5 filed on December 21, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to a pointer for an aircraft capable of hovering.

[0004] In particular, the present invention relates to a method for a helicopter, a tiltrotor aircraft or a helicoplane.

[0005] The invention also relates to a method for assisting in the operation of such an aerial vehicle capable of hovering. Background Art

[0006] As is known, a helicopter comprises a motor system, a main rotor driven by the motor system and adapted to provide the lift required to maintain the helicopter and the thrust required for directional control of the helicopter.

[0007] As we all know, tiltrotor aircraft include:

[0008] - a fuselage extending along a first longitudinal axis;

[0009] - a fixed wing extending along a second transverse axis of the tiltrotor aircraft and inclined relative to the first longitudinal axis; and

[0010] A pair of rotors rotatable about respective third axes and tiltable relative to the second axis.

[0011] The tiltrotor aircraft can switch between the following configurations:

[0012] - an aircraft configuration in which the respective third axis of the rotor is parallel to the first axis; and

[0013] - A helicopter configuration in which the respective third axis of rotation of the rotor is inclined relative to the first axis.

[0014] In the aircraft configuration, the rotor behaves like a conventional aircraft propeller and generates the thrust required to maintain the aircraft itself. In this configuration, the lift required to maintain the aircraft is provided by the fixed wings.

[0015] In a helicopter configuration, the rotors provide both the lift required to maintain it and the thrust required to operate the tiltrotor along said first and second axes.

[0016] With respect to helicopters and tilt-rotor aircraft configured as helicopters, it is known that actuation of the rotors results in a vertical airflow through the rotors.

[0017] During normal operation, the actuation of the rotor generates lift, which results in a vertical airflow from the top downward through the rotor itself.

[0018] A portion of this airflow recirculates upward near the free end of the blade and merges with the vertical airflow downward from the top.

[0019] More precisely, this part of the airflow generates a tip vortex which creates aerodynamic drag and reduces the aerodynamic efficiency of the blade. In more detail, a vortex is formed at the end of each blade which is actually called a tip vortex having an annular shape.

[0020] As long as this tip vortex remains below a certain size, the overall efficiency loss of the rotor remains small.

[0021] However, when a helicopter / tilt-rotor aircraft arranged in a helicopter configuration is in a descending condition, the aircraft straddles the downflow, causing the tip vortex to increase in size.

[0022] This results in a condition known as a "vortex ring regime" where rotor power is used only to supply an annular air circulation around the rotor.

[0023] When the rate of descent exceeds a threshold, the aforementioned phenomenon intensifies and generates turbulence over the relevant area of ​​the rotor, thus significantly reducing its aerodynamic efficiency, even if the motor system continues to power the rotor.

[0024] In this case, the helicopter / tilt-rotor aircraft becomes unstable and experiences strong oscillations, such as pitch and / or roll oscillations.

[0025] A vortex ring state condition occurs when a helicopter / tilt-rotor aircraft configured as a helicopter has a sink rate greater than a first threshold typical of an aircraft, using only a fraction of the motor power and with a translational forward speed less than a second threshold.

[0026] Operations that may typically produce vortex ring conditions are high-altitude hovering operations without precise altitude control and landing operations with extremely high descent rates.

[0027] Patent application EP-A-1620311 discloses a method for identifying a vortex ring condition and automatically overcoming it.

[0028] Patent applications US-B-9,037,316, EP-B-2212296, EP-B-3263452 and EP-3406562 disclose methods for identifying a vortex ring condition and notifying the crew of the condition.

[0029] The need to concisely and immediately clearly inform the flight crew that an aircraft is approaching or in a vortex ring state condition is recognized in the art.

[0030] US-A-2016 / 288922 discloses an aircraft capable of hovering according to claim 1 and a method for assisting in the operation of an aircraft according to claim 3 .

[0031] CN-A-110901897 discloses an early warning separation control method for an unmanned helicopter's vortex ring state. This method effectively implements vortex ring early warning and early protection functions, provides a solution that enables rapid and reasonable separation even when a vortex ring state has been entered, and ensures the flight safety of the unmanned helicopter. This early warning separation control method for an unmanned helicopter's vortex ring state can determine the unmanned helicopter's current safety status in real time, and transmit this status information to the control terminal to alert the operator to issue an early warning. Furthermore, this early warning separation control method is stable, reliable, and provides high early warning accuracy, significantly improving the flight safety of the unmanned helicopter.

[0032] EP-A-3477261 discloses a flight instrument warning configured to automatically adjust a low airspeed warning band on an airspeed indicator based on available torque margin and radar altimeter altitude. Summary of the Invention

[0033] The object of the present invention is to realize an aircraft capable of hovering that allows satisfying at least one of the above-mentioned needs in a simple and economical manner.

[0034] The above-mentioned purpose is achieved by the hovering aircraft provided by the present invention.

[0035] The present invention also provides a method for assisting in the operation of an aircraft configured to hover. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further features and advantages of the present invention will become apparent from the following detailed description given by way of non-limiting example and with reference to the accompanying drawings, in which:

[0037] Figure 1-3 shows a side view of an aircraft including an indicator according to the present invention;

[0038] Figure 4 An indicator constructed according to the present invention is shown;

[0039] Figure 5 and 6 Shown Figure 1-3 Another indicator of the aircraft, on which is displayed Figure 1-3 A visual signal output by the control unit of the aircraft;

[0040] Figure 7 Shown Figure 1-3 Some parts of the aircraft cockpit, emphasizing Figure 4 、 5 and the position of the indicator shown at 6;

[0041] Figure 8 shows a plurality of flight envelopes stored in a memory level of the control unit; and

[0042] Figure 9 Schematically shows Figure 1-3 Additional components of the aircraft. DETAILED DESCRIPTION

[0043] Reference Attachment Figure 1-3 , 1 indicates an aircraft that can hover, that is, it can maintain flight at a constant altitude and zero speed.

[0044] In the example shown, the aircraft 1 is a tiltrotor aircraft.

[0045] Alternatively, the aircraft 1 may be a helicopter or a rotary-wing aircraft.

[0046] It must be noted that in the disclosure provided below, expressions such as "upper", "lower", "in front", "in rear", etc. are directed to forward flight conditions or Figure 1-3 The tiltrotor aircraft 1 is shown to be used in a "hover" position.

[0047] The tiltrotor aircraft 1 basically comprises:

[0048] - a fuselage 2 having an axis of longitudinal extension A;

[0049] a pair of half-wings 3 projecting in a cantilevered manner from respective portions of the fuselage 2 facing each other and transverse to the axis A;

[0050] a pair of motors 4 supported by the respective half-wing 3 and each arranged at the intersection of the relative half-wing 3 with the fuselage 2 ; and

[0051] a pair of rotors 5 operatively connected to respective motors 4 and rotatable about respective axes B.

[0052] Tiltrotor aircraft 1 further comprises a pair of nacelles 10 housing respective rotors 5 .

[0053] The tiltrotor aircraft 1 further comprises a plurality of brackets 6 arranged below the fuselage 2 relative to the normal operating position of the tiltrotor aircraft 1, such as Figure 2 shown.

[0054] The tiltrotor aircraft comprises a pair of axes E associated with respective half-wings 3. Each axis E is parallel to the centre line of the respective half-wing 3 and may have an anhedral angle relative to the fuselage 2.

[0055] In the example shown, the axis E is orthogonal to the axis A and is arranged horizontally in a plan view of the tiltrotor aircraft 1 .

[0056] Each half-wing 3 generates a lift having a main component along an axis Z orthogonal to the axes A, E.

[0057] The tiltrotor aircraft 1 can be selectively configured by tilting the rotor 5 about the axis E:

[0058] - "Helicopter" structure (in Figure 1 ), in which the axis B of the rotor 5 is inclined relative to the axis A and is orthogonal to the axis E; and

[0059] - "Aircraft" structure (in Figure 1-3 ), where the axis B of the rotor 5 is parallel to the axis A and orthogonal to the axis E.

[0060] A tiltrotor aircraft 1 arranged in a "helicopter" configuration and operating at a low forward speed and a high rate of descent is at risk of being in a vortex ring state condition.

[0061] In this case, the aerodynamic efficiency of the rotor 5 is greatly reduced, which poses a risk to the tiltrotor aircraft 1 .

[0062] The tilt-rotor aircraft 1 also includes ( Figure 4-8 ):

[0063] - cockpit 15;

[0064] - a plurality of indicators 16a, 16b, 16c;

[0065] - a plurality of sensors 25a, 25b adapted to detect corresponding flight parameters; and

[0066] - A control unit 30 programmed to receive the flight parameters detected by the sensors 25a, 25b.

[0067] More specifically, the indicator 16a is a vertical speed indicator.

[0068] Sensor 25a (only in Figure 8 ) is configured to detect the rate of descent ROD of the tiltrotor aircraft 1 .

[0069] Sensor 25b (only in Figure 8 ) is configured to detect the air pressure altitude PALT and air speed ASP of the tilt-rotor aircraft 1 .

[0070] The indicator 16b is an instrument known as an attitude and direction indicator "ADI".

[0071] The indicator 16 b integrates the functionality of an attitude indicator or “artificial horizon” and a “flight indicator”, ie it provides an indication of the optimal flight trajectory for maintaining the desired flight path.

[0072] In more detail, the indicator 16b includes ( Figure 5 and 6 ):

[0073] - an indication 17 of the tiltrotor aircraft 1; and

[0074] A circular area 18 having a center O and rotatable about the center O relative to the indication 17 on the basis of the tilt angle of the tiltrotor 1 relative to the axis A, ie on the basis of the roll angle of the tiltrotor 1 itself.

[0075] Region 18 also includes:

[0076] an angular scale 19 associated with the angle between the axis of the tiltrotor 1 and a fixed direction, ie with the pitch angle; and

[0077] A linear scale 20 correlates to the angle of inclination of the tiltrotor 1 relative to the axis E, ie to the roll angle of the tiltrotor 1 .

[0078] The position of the indicator 17 on the scales 19 , 20 represents the respective pitch and roll angles of the tiltrotor aircraft 1 .

[0079] The control unit 30 is configured as follows:

[0080] - Processing of the inertial vertical speed IVS indication based on the vertical speed VS and the pressure altitude PALT; and

[0081] - The value of the inertial vertical velocity IVE is displayed on the indicator 16a.

[0082] For example, Figure 4 As shown, the indicator 16a comprises in particular:

[0083] - vertical speed indication 35;

[0084] - a graduated scale 36 on which are displayed a plurality of graduated lines 37 associated with respective vertical speed values; and

[0085] A pointer 38 that moves on the graduated scale 36 so as to overlap a graduated line 37 corresponding to the respective synchronous vertical speed value of the tiltrotor aircraft 1 .

[0086] The control unit 30 also comprises a memory stage 50 in which are stored paired values ​​of the rate of descent ROD and the airspeed ASP.

[0087] In more detail, the data storage level 50 stores:

[0088] a first pair of values ​​of the descent rate ROD and the airspeed ASP corresponding to the safe flight envelope 51 of the tiltrotor aircraft 1 ;

[0089] a second pair of values ​​of the rate of descent ROD and the airspeed ASP corresponding to the flight envelope 52 of the tiltrotor aircraft 1 in a state close to a vortex ring; and

[0090] a third pair of values ​​of the descent rate ROD and the airspeed ASP corresponding to the flight envelope 53 for the tiltrotor aircraft 1 in the vortex ring state.

[0091] The storage level 50 stores:

[0092] a fourth pair of values ​​of the descent rate ROD and the airspeed ASP corresponding to the boundary broken line 54 between the flight envelopes 51 , 52 ; and

[0093] A fifth pair of values ​​of the descent rate ROD and the airspeed ASP corresponding to the boundary broken line 55 between the flight envelopes 52 , 53 .

[0094] The broken line 54 comprises in particular:

[0095] - a segment 60 corresponding to a constant value ROD1 of the descent rate ROD and an increasing value of the airspeed ASP comprised between zero and ASP1;

[0096] a segment 61 corresponding to the increasing value of the descent rate ROD comprised between ROD1 and ROD2 and the increasing value of the airspeed ASP comprised between ASP1 and ASP2 ; and

[0097] A segment 62 corresponds to an increasing value of the descent rate ROD comprised between ROD2 and ROD6 and a constant value of the airspeed ASP equal to ASP2 .

[0098] The broken line 55 comprises in particular:

[0099] - a segment 63 corresponding to a constant value ROD4 of the descent rate ROD and an increasing value of the airspeed ASP comprised between zero and ASP4;

[0100] a segment 64 corresponding to the increasing values ​​of the descent rate ROD comprised between ROD4 and ROD5 and the decreasing values ​​of the airspeed ASP comprised between ASP4 and ASP5 ; and

[0101] A segment 65 corresponds to an increasing value of the descent rate ROD comprised between ROD5 and ROD6 and a constant value of the airspeed ASP equal to ASP5 .

[0102] Specifically, the values ​​ASP1 and ASP4 are equal to each other and the value ASP2 is greater than the value ASP5.

[0103] The value ROD6 (ROD3) is greater than the value ROD5 (ROD2), which in turn is greater than the value ROD4 (ROD1).

[0104] The value ROD6 (ROD5, ROD4) is greater than the value ROD3 (ROD2, ROD1).

[0105] In the example shown, the segments 60 , 61 , 62 ; 63 , 64 , 65 correspond to straight line segments.

[0106] The segments 60 , 63 ; 61 , 64 ; 62 , 65 are parallel to each other.

[0107] The indicator 16a includes ( Figure 4 ) area 100, in which an indication 101 associated with a situation in which the tiltrotor aircraft 1 is approaching a vortex ring state can be displayed.

[0108] The indicator 16a also includes a region 102 in which an indication 103 associated with the situation in which the tiltrotor aircraft 1 is in a vortex ring state can be displayed.

[0109] More specifically, the indications 101 , 103 overlap with the graduated scale 36 .

[0110] More specifically, the indication 101 overlaps with the corresponding graduated line 37 a corresponding to the first value of the descent rate of the graduated scale 36 , and the indication 103 overlaps with the corresponding graduated line 37 b corresponding to the second value of the descent rate of the graduated scale 36 .

[0111] The second value is greater than the first value in absolute value.

[0112] In particular, the indication 103 is displayed in a first color, which in the preferred embodiment is yellow.

[0113] The indication 101 is displayed in a second color, which in the preferred embodiment is red.

[0114] The control unit 30 is programmed to command the display of indications 101 , 103 on the indicator 16 a based on the flight parameters detected by the sensors 25 a , 25 b .

[0115] The tiltrotor aircraft 1 further comprises:

[0116] - a visual signal generator 80 at a different location in the cockpit 15 than the indicator 6a;

[0117] - Sound signal generator 90.

[0118] The generator 80 is controlled by the control unit 30 based on the flight parameters detected by the sensors 25a, 25b to ( Figure 5 and 6 ):

[0119] - generating a first visual signal 121 when the tiltrotor aircraft 1 is in the flight envelope 52 and approaches a vortex ring state condition ( Figure 6 );and

[0120] - generating a second visual signal 122 when the tiltrotor aircraft 1 is in the flight envelope 53 and in a vortex ring state condition ( Figure 5 ).

[0121] In particular, the first visual signal 121 and the second visual signal 122 are respectively reproduced in a first color (yellow in the embodiment shown) and a second color different from the first color (red in the embodiment shown).

[0122] The first visual signal 121 and the second visual signal 122 have a rectangular shape and are displayed in the same area within the area 18 of the indicator 16 b .

[0123] Specifically, the visual signals 121 , 122 are displayed by flashing for a predetermined time range, for example, 5 seconds.

[0124] The generator 90 is controlled by the control unit 30 based on the flight parameters detected by the sensors 25a, 25b to:

[0125] - generating a first acoustic signal when the tiltrotor aircraft 1 is in the flight envelope 51 and approaches a vortex ring state condition; and

[0126] - generating a second acoustic signal when the tiltrotor aircraft 1 is in the flight envelope 52 and in a vortex ring state condition.

[0127] In the example shown, the first sound signal and the second sound signal are obtained by speech synthesis of the messages “rate of descent too great” and “vortex, vortex”, respectively.

[0128] The control unit 30 may be connected to an autopilot system in order to perform automatic emergency maneuvers if the tiltrotor aircraft 1 is within the flight envelope 52 , 53 .

[0129] The operation of the tiltrotor aircraft 1 is disclosed hereinafter with reference to the case where the tiltrotor aircraft 1 is in a “helicopter” configuration.

[0130] Indicator 16a indicates to the crew the value of the vertical speed of tiltrotor aircraft 1. At the same time, indicator 16b indicates the attitude of tiltrotor aircraft 1 and provides an indication of the optimal flight trajectory for tiltrotor aircraft 1 to maintain the desired flight path.

[0131] The control unit 30 determines whether the tiltrotor aircraft 1 is within the flight envelope 51 , 52 , 53 based on the flight parameters detected by the sensors 25 a , 25 b .

[0132] When tiltrotor aircraft 1 is in flight envelope 51 with substantially no risk of experiencing a vortex ring condition, indications 101, 103 are not displayed and visual signals 121, 122 are not displayed within region 18. Furthermore, generator 90 does not generate the first and second acoustic signals.

[0133] If the tiltrotor aircraft 1 is in a flight envelope 52 close to a vortex ring condition, the controller 30 decides to display an indication 103 in the area 102 of the indicator 16a and the generator 80 displays a visual signal 122 in yellow in the area 18 of the indicator 16b. The generator 90 also decides to emit a second sound signal.

[0134] Thus, the pilot is promptly warned that the tiltrotor aircraft 1 is approaching a dangerous situation and can perform maneuvers to move out of the vortex ring condition.

[0135] If the tiltrotor aircraft 1 is in a flight envelope 53 close to a vortex ring condition, the control unit 30 decides to display an indication 101 in the area 100 of the indicator 16a and the generator 80 displays a visual signal 121 in red in the area 18 of the indicator 16b. The generator 90 also decides to emit a first acoustic signal.

[0136] Thus, the pilot is warned that the tiltrotor aircraft 1 is in a dangerous situation and must perform an operation in time to move out of the vortex ring situation.

[0137] After considering the characteristics of the indicator 16a, the method for assisting in the operation of the tiltrotor aircraft 1 according to the invention, the advantages it allows to obtain are evident.

[0138] In more detail, an indication 101 associated with the situation of reaching the vortex ring state is displayed in the area 100 of the indicator 16 a provided for displaying the vertical speed of the tiltrotor aircraft 1 itself.

[0139] Similarly, an indication 103 associated with an approaching vortex ring state condition is displayed in region 102 of indicator 16a.

[0140] Thus, indications 101 , 103 concisely and immediately clearly inform the crew that tiltrotor aircraft 1 is approaching or in a vortex ring state condition, enabling the crew to perform appropriate corrective actions.

[0141] By issuing the indications 101, 103 on the vertical speed indicator 16a, they are immediately visible to the pilot.In practice, vortex ring state situations preferably occur at high vertical speeds, ie when the crew is continuously monitoring the indicator 16a.

[0142] The visual signals 121 , 122 and the first and second acoustic signals also inform the crew that the tiltrotor aircraft 1 is respectively within the flight envelope 52 , 53 .

[0143] It is therefore obvious that modifications and variations can be made to the indicator 16 a and to the method for assisting in the operation of the tiltrotor aircraft 1 described above without departing from the scope of protection of the present invention.

[0144] In particular, the aircraft 1 may not have a crew or may be a drone.

[0145] In this case, the indicator 16a would be provided on a remote interface controlled by the user at the surface.

Claims

1. An aircraft capable of hovering, comprising: sensor devices (25a, 25b) configured to detect flight parameters of the aircraft (1); as well as indicator (16a), The indicator (16a) comprises: a first indication (35) associated with the vertical speed of the aircraft (1); a first region (100) in which a second indication (101) associated with a condition in which a vortex ring state is reached can be displayed; and a second region (102) in which a third indication (103) associated with an approaching vortex ring state condition can be displayed, The second indication (101) overlaps with a first portion of the first indication (35) corresponding to a first value of the descent vertical speed, the third indication (103) overlaps with a second portion of the first indication (35) corresponding to a second value of the descent vertical speed, the first value is greater than the second value in absolute value, wherein the second indication (101) is displayed in a first red color during use, and the third indication (103) is displayed in a second yellow color different from the first red color during use, The aircraft (1) further comprises a control unit (30) configured to command the display of the second indication (101) on the indicator (16a), also based on the flight parameters (ROD, PALT; ASP), The aircraft (1) further comprises a first generating device (90) for generating a first sound signal and a second sound signal, The first generating device (90) is also controlled by the control unit (30) based on the flight parameters. The first sound signal is associated with the reaching of the vortex ring state, The second sound signal is associated with the state of the approaching vortex ring, Characterized in that the aircraft (1) comprises a second generating device (80) configured to display a third visual signal and a fourth visual signal, The third visual signal is associated with the reaching vortex ring state condition and is displayed in the first red color when in use, The fourth visual signal is associated with the approaching vortex ring state condition and is displayed in the second yellow color when in use, The aircraft (1) comprises a further indicator (16b) comprising an area (18) in which a fourth indication (17) associated with the attitude of the aircraft (1) can be displayed, The third visual signal (121) and the fourth visual signal (122) are displayed on the further indicator (16b).

2. The aircraft according to claim 1, characterized in that The control unit (30) is configured to command the display of the third indication (103) on the indicator (16a) also based on the flight parameter.

3. A method for assisting in the operation of an aircraft (1), the aircraft (1) being an aircraft according to claim 1 configured to be able to hover, comprising the following steps: i) detecting whether the aircraft (1) is in an actual vortex ring state; ii) displaying on the indicator (16a) a first indication (35) associated with the vertical speed value of the aircraft (1); and iii) displaying a second indication (101) associated with the reaching of the actual vortex ring state on the first area (100) of the indicator (16a), The method further comprises the following steps: iv) detecting a state in which the aircraft (1) is close to an actual vortex ring; v) displaying a third indication (103) associated with the aircraft (1) approaching the actual vortex ring state on the second region (102) of the indicator (16a); vi) overlapping the second indication (101) with a first portion of the first indication (35) corresponding to a first value of the descent vertical speed; and vii) overlapping the third indication (103) with a second portion of the first indication (35) corresponding to a second value of the descent vertical speed, The first value is greater than the second value in absolute value; viii) displaying the second indication (101) in a first red color; and ix) displaying the third indication (103) in a second yellow color different from the first red color; x) generating a first sound signal and a second sound signal, The first sound signal is associated with the reaching of the vortex ring state, The second sound signal is associated with the state of the approaching vortex ring, Characterized in that the method comprises the step xi): displaying a third visual signal (121) and a fourth visual signal (122) on a further indicator (16b), the further indicator (16b) comprising an area (18) in which a fourth indication (17) associated with the attitude of the aircraft (1) can be displayed; The third visual signal (121) is associated with the reaching of the vortex ring state condition and is displayed in the first red color, The fourth visual signal (122) is associated with the approaching vortex ring state condition and is displayed in the second yellow color.

4. The method according to claim 3, characterized in that The method comprises the step xii): displaying the second indication (101) and the third indication (103) on the indicator (16a).

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