Aircraft with pivoting landing gear provided with pivoting locking system and monitoring system

Abstract

The invention relates to an aircraft having a pivot landing gear provided with a pivot locking system and a monitoring system. An aircraft having a landing gear (10) provided with a bracket (11) and a pivot assembly (12), the landing gear (10) having a pivot locking system (20) comprising a channel (22) provided in a base (21) and a movable locking finger (25). The monitoring system (50) is configured to determine the presence of a risk of sudden yaw movement of the aircraft with takeoff or unlocking of the landing gear (10) when locking the fingers (25) in a locked mode on the ground, the monitoring system (50) being configured to send a risk signal to the processing system (60) after determining that the risk of sudden yaw movement is present.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of French patent application FR 2412543, filed on November 18, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to an aircraft having a pivot landing gear equipped with a pivot locking system and a monitoring system.

[0004] The landing gear of an aircraft (such as a rotorcraft or helicopter) may include at least one pivot landing gear. Such a pivot landing gear may include an assembly that carries at least one ground contact member and is capable of pivoting 360 degrees about a pivot axis to facilitate the movement of the aircraft on the ground. The term "ground" hereafter refers to any surface on which the aircraft may land, such as the Earth's surface, the roof of a building, the deck of a ship, etc.

[0005] For example, a tricycle-type rotorcraft may include two main landing gears and one auxiliary landing gear, each landing gear including at least one wheel. The two main landing gears cannot pivot. However, the auxiliary landing gear can pivot to ensure the aircraft's maneuverability on the ground. When on the ground, one or more wheels of the auxiliary landing gear pivot freely about a pivot axis separate from one or more axes of rotation of the wheels. In helicopters equipped with a yaw control system and, for example, a rear rotor, rotation on the ground can be achieved by controlling the thrust applied by the yaw control system. The yaw control system generates a torque on the fuselage of the aircraft carried by the landing gear, and this torque automatically pivots the auxiliary landing gear to orient the aircraft in the desired direction.

[0006] However, such pivoting landing gear is typically equipped with a pivot locking system. Upon command, the pivot locking system locks the pivoting landing gear to a predetermined position that allows the aircraft to move in a straight line. Then, one or more wheels of the pivoting landing gear are essentially on the longitudinal axis of the aircraft.

[0007] Known pivot locking systems include locking fingers that can enter holes in the base of a pivot assembly fixed to the pivoting landing gear. Furthermore, the pivot locking system includes a resilient connecting rod connected to the locking fingers and, in particular, connected to a handle via a ball control. To place the pivot locking system in the unlocked mode, the operator operates the handle to position the locking fingers outside the holes. Thus, the pivoting assembly pivots freely about the pivot axis. To lock the pivoting landing gear, the operator operates the handle to position the locking fingers within the holes.

[0008] This pivot locking system is effective. However, when the pivot landing gear is locked, the pilot may mistakenly apply excessive yaw control. The aircraft then remains stable on the ground due to the force at the contact point between the wheels and the ground. However, if the crew unlocks the pivot landing gear, this balance is disrupted, which can cause the aircraft to yaw suddenly. Similarly, if the aircraft takes off under these conditions, this balance is also disrupted, and without a rapid response from the pilot, the aircraft begins to rotate along the yaw axis. Background Technology

[0009] Documents US3375999, EP 662906B1, CN104210654 A, EP 0 662 906 B1, US 2 502522A, US2 211 484 A, US11 794 884 B1 and US2018 / 372535 A1 are known. Summary of the Invention

[0010] Therefore, the object of this invention is to provide a landing gear with an innovative design to limit the risk of sudden instability.

[0011] Therefore, the present invention relates to an aircraft equipped with a pivoting landing gear having a support and a pivoting assembly carrying a contact member configured to contact the ground, the pivoting assembly being rotatable about a pivot axis relative to the support, the pivoting landing gear having a pivot locking system including a channel disposed in a base and movable locking fingers, the locking fingers being located outside the channel in an unlocked mode to allow the pivoting assembly to pivot freely relative to the support, the locking fingers being placed in the channel in a locked mode to restrict pivoting, the locking fingers being carried by the support, and the base being part of the pivoting assembly.

[0012] The aircraft includes a monitoring system configured to determine the presence of a risk of sudden yaw motion of the aircraft when the locking finger is in a locked mode on the ground, during takeoff or when the pivot landing gear is unlocked. The monitoring system is also configured to send a risk signal to a processing system after determining that there is a risk of sudden yaw motion.

[0013] The term "signal" in the following text refers, for example, to an analog, digital, electrical, or optical signal carrying data.

[0014] Therefore, when the pivot locking system is in locked mode, the monitoring system allows for the determination of any risk of instability in the aircraft when the pivot landing gear is unlocked or during takeoff, and thus allows for control of the aircraft's systems to limit such instability risks. The pilot can optionally apply flight controls to reduce the yaw moment applied to the aircraft. Thus, pilot maneuvering eliminates the risk of sudden yaw motion. The pilot can then choose to safely unlock the landing gear and / or takeoff.

[0015] Therefore, the monitoring system can limit the risk of aircraft instability associated with pilot error even in the presence of locked pivot landing gear.

[0016] Landing gear may also include one or more of the following features, either individually or in combination.

[0017] In one possibility, the processing system may include an alarm generator that generates an alarm upon receiving a risk signal.

[0018] The alarm generator can warn the crew of the risk of a sudden yaw.

[0019] According to one possibility compatible with the foregoing possibilities, the processing system may include a suppressor that keeps the locking finger in a locked mode after receiving a risk signal.

[0020] The suppressor is then automatically activated to lock the locking fingers in the locked mode. Therefore, the pilot cannot accidentally unlock the pivot landing gear when there is a risk of instability. On the other hand, the pilot can reduce the yaw moment applied to the aircraft. When the pilot maneuvers to eliminate the risk of sudden yaw, no further risk signals are sent to the suppressor, and the suppressor is deactivated. The pilot can then safely unlock the pivot landing gear.

[0021] Optionally, the suppressor may include a locking actuator that holds the locking finger in a locked mode by interfering with the shape of the locking finger or with the shape of a control that controls the movement of the locking finger, or by suppressing such a control.

[0022] According to one alternative, the locking finger can be made movable by an electric actuator. The suppressor can then include components that suppress the electric actuator by, for example, electronic logic implemented in the electric actuator or by cutting off the power supply to the electric actuator.

[0023] According to an alternative, the locking fingers can be made movable via a mechanical system. In this case, a dedicated actuator can be used to brake or lock the locking fingers or the mechanical system.

[0024] According to a possibility compatible with the foregoing, the monitoring system can be configured to determine the risk of sudden yaw motion when the value related to the force in the locking system is greater than a limit.

[0025] In practice, if an aircraft experiences a significant yawing moment that could produce a sudden yawing motion, the locking system experiences significant forces. Shear forces exerted by the base on the locking fingers or forces exerted by the locking fingers on the bearings guiding them tend to increase until they exceed a limit. This limit can be established through analysis following trials, tests, and / or simulations. For example, the limit can be determined based on the angular acceleration the aircraft will experience during takeoff or landing gear unlocking. The limit can also be established based on dedicated tests designed to estimate the pilot's ability to avoid loss of stability in the event of a sudden yawing rotation of the aircraft and under various load levels with the locking fingers present. The limit can also be evaluated based on the yawing commands to be applied to counteract the effects of stability loss.

[0026] If the monitoring system determines that the value of the force that varies with or is applied to the locking fingers exceeds a limit, the monitoring system infers that the aircraft is at risk of instability and therefore controls the processing system.

[0027] According to one possibility compatible with the foregoing possibilities, the monitoring system may include at least one sensor and a controller for measuring the value, the sensor sending a measurement signal carrying the value to the controller, the controller being configured to determine whether the value is above a limit and thus generate a risk signal.

[0028] Therefore, the monitoring system includes at least one sensor and a controller that compares measurements to limits to determine whether a risk signal should be issued. Thus, the crew is informed of a risk of instability if the pivot landing gear is unlocked or if the aircraft takes off.

[0029] Optionally, a preventative warning may be issued if the value is between a predetermined threshold and the limit.

[0030] According to one possibility, the sensor may include at least one stress measuring instrument arranged on the locking finger and measuring the value, wherein the force is a shear force applied to the locking finger, more precisely a shear force applied to the locking finger by the base.

[0031] The value associated with the force can be determined in a conventional manner using one or more stress measuring instruments.

[0032] According to another possibility, the sensor may include an integrated sensing bearing that guides the locking fingers and measures the value, the force being the force applied to the integrated sensing bearing by the locking fingers.

[0033] In this case, the bearing may include at least one stress measuring instrument for routinely measuring values ​​related to the force applied to the instrument bearing by the locking fingers, which is actually a mirror image of the yaw moment applied to the aircraft.

[0034] According to another possibility, the monitoring system may include at least two alarm microswitches disposed on either side of the monitored finger, for example in a plane perpendicular to the pivot axis. When the value exceeds a limit in the presence of a pivoting component pivoting relative to the support in one direction, the alarm microswitches are activated. Each activated alarm microswitch emits an alarm signal indicating a risk signal sent to the processing system, or the alarm signal is sent to the controller, which then issues a risk signal.

[0035] The monitoring system may have two alarm microswitches to account for possible pivoting of the pivoting component in two opposite directions.

[0036] Optionally, the system may include two warning microswitches to generate a preventative warning before issuing an alarm signal.

[0037] According to another possibility, the monitoring system may include a position sensor that measures the current position of the aircraft's yaw control and a velocity sensor that measures the current rotational speed of the aircraft's lift rotor. The monitoring system includes a controller that communicates with the position sensor and the velocity sensor and is configured to issue a risk signal based at least on the current position and the current rotational speed.

[0038] In practice, on rotorcraft and, for example, helicopters, the risk of losing control of the aircraft during unlocking of the pivoting landing gear on the ground or during takeoff can be identified, at least based on the position of the yaw control obtained, for example, at the control stick, and the rotational speed of the boosted rotor. The current position of the yaw control can be measured in a conventional manner and is expressed, for example, as a yaw angle. Similarly, the current rotational speed can be measured in a conventional manner and is expressed, for example, as a percentage of the nominal rotational speed.

[0039] For example, the controller can be configured to estimate the current yaw moment based on the current position and current rotational speed, or based on the current position and current rotational speed and the position of the component used to control the total pitch of the blades of the lifting rotor, measured using complementary sensors, and generate the risk signal if the current yaw moment is greater than the limit moment.

[0040] For example, the controller stores a law that gives the current yaw moment based on the current position and current rotational speed, and possibly also based on the position of a component used to control the collective pitch of the rotor blades. Such a component can take the form of, for example, a conventional collective pitch joystick. Here and below, the term "law" refers to mathematical laws, value tables, neural networks, etc. Laws can be established, for example, through experimentation, calculation, and / or simulation.

[0041] In another example, the controller is configured to determine the current yaw moment based solely on the current position, or based on the current position and the position of a component used to control the total pitch of the blades of the lifting rotor, measured using complementary sensors. The controller is configured to generate the risk signal if the current yaw moment is greater than a limit moment and if the current rotational speed is simultaneously greater than a predetermined speed threshold.

[0042] In this simplified variant, the controller considers the position of yaw control, or even the position of the component used to control the total pitch of the blades of the lifting rotor, in order to assess the current yaw moment, but is activated only based on the rotor's rotational speed threshold.

[0043] According to one possibility compatible with the foregoing possibilities, the aircraft may include an auxiliary landing gear and two main landing gears, the pivot landing gear forming the auxiliary landing gear.

[0044] The present invention also relates to a method for monitoring an aircraft including a pivoting landing gear having a support and a pivoting assembly, the pivoting assembly carrying a contact member configured to contact the ground, the pivoting assembly being rotatably movable relative to the support about a pivot axis, the pivoting landing gear having a pivot locking system including a channel disposed in a base and movable locking fingers, the locking fingers being outside the channel in an unlocked mode to allow free pivoting of the pivoting assembly relative to the support, and the locking fingers being placed in the channel in a locked mode to restrict pivoting, the locking fingers being carried by the support, and the base being part of the pivoting assembly. The method particularly includes:

[0045] • When the locking finger is in the locked mode on the ground, a monitoring system is used to determine the presence of a risk of sudden yaw motion of the aircraft during takeoff or when the pivot landing gear is unlocked; and

[0046] • After determining that the aircraft is at risk of sudden yaw using the monitoring system, a risk signal is sent to the processing system.

[0047] The method may also include the steps described above. Attached Figure Description

[0048] The invention and its advantages will become more apparent from the following description of examples given by way of illustration with reference to the accompanying drawings, wherein:

[0049] Figure 1 This is a diagram illustrating a rotorcraft according to the present invention;

[0050] Figure 2 It is shown Figure 1 A top view of a rotorcraft;

[0051] Figure 3 The figure details an example of a pivot landing gear with a locking system according to the invention in locked mode;

[0052] Figure 4 This is a diagram illustrating an example of a monitoring system according to the present invention;

[0053] Figure 5 This is a diagram illustrating an example of a monitoring system according to the present invention;

[0054] Figure 6 This is a diagram illustrating an example of a monitoring system according to the present invention;

[0055] Figure 7 This is a diagram illustrating an example of a monitoring system according to the present invention;

[0056] Figure 8 These are figures detailing examples of a monitoring system according to the present invention; and

[0057] Figure 9 The figure is a detailed illustration of an example of a monitoring system according to the present invention. Detailed Implementation

[0058] Elements present in more than one figure are given the same reference numerals in each figure.

[0059] Figure 1 An aircraft 1 according to the present invention is shown. The aircraft 1 includes a fuselage 2, which optionally carries at least one lift rotor 4, i.e., a rotor that at least contributes to the lift of the aircraft 1 or also contributes to its propulsion. In this case, the aircraft 1 shown is a helicopter with a lift rotor 4 and a yaw control system that may include a tail rotor 5. Other yaw control systems are also possible, for example, systems known by the brand name NOTAR (tailless rotor system). The total pitch of the blades of the lift rotor 4 can be determined by… Figure 9 The thrust generated by the yaw control system can be controlled by the control component 91 shown. Figure 9The yaw control 97 (e.g., a rudder stick) is used for control. Furthermore, the fuselage 2 is mounted on a landing gear system 6, which includes, for example, at least one landing gear, namely, in this example, two main landing gears 7 and an auxiliary landing gear 8. Independent of the nature of the aircraft 1, the aircraft 1 specifically includes at least one pivot landing gear 10, i.e., the auxiliary landing gear 8 according to this example.

[0060] refer to Figure 2 When the yaw control system applies a lateral thrust F1, the pivot landing gear 10 rotates on the ground about the pivot axis AXP to change the orientation of the rotorcraft 1. Therefore, the landing gear 10 includes a pivot locking system to keep the pivot landing gear 10 substantially aligned along the forward axis of the rotorcraft 1 under certain conditions.

[0061] Figure 3 An exemplary embodiment of the pivoting landing gear 10 according to the present invention is shown. Regardless of the embodiment, the landing gear 10 is provided with a support 11 connected to the fuselage 2, and a pivot assembly 12 pivotable relative to the support 11 about a pivot axis AXP. The pivot assembly 12 carries at least one contact member 15 configured to contact the ground 100. For example, the contact member 15 includes a wheel 150 rotatably movable relative to the pivot assembly 12 about the pivot axis AXROT.

[0062] As an explanation, Figure 3 An example of a bracket 11 and a pivot assembly 12 is shown, but other embodiments of the bracket 11 and pivot assembly 12 are possible. In particular, the bracket 11 may be fixed or retractable without departing from the scope of the invention. According to the example shown, the pivot assembly 12 may include a cylinder 13 capable of rotatably moving relative to the bracket 11 about a pivot axis AXP. Furthermore, the pivot assembly 12 includes a shock absorber 14 carried by and at least partially housed within the cylinder 13. Additionally, a scissor brace 16 is hinged to the cylinder 13 and the shock absorber 14. For example, at least one contact member 15 may be carried by either the scissor brace 16 or the shock absorber 14.

[0063] Regardless of the implementation of the pivot assembly 12 and the support 11, the landing gear 10 includes a pivot locking system 20 configured to: i) fix the pivot assembly 12 relative to the support 11 during the locked mode MODV, except for the operating gap, and ii) allow, but not limited to, pivot assembly 12 to pivot relative to the support 11 about the pivot axis AXP during the unlocked mode MODDV.

[0064] The pivot locking system 20 includes a locking finger 25 movable relative to a channel 22 disposed in a base 21 to request the application of a locking mode MODV. The locking finger 25 is supported by a bracket 11, and the base 21 is part of the pivot assembly 12. For example, the base 21 is coupled with... Figure 3 The cylinder body 13 is formed as a single-piece component. Then, in the unlocked mode MODDV, the locking finger 25 is outside the channel 22 to allow the pivot assembly 12 to pivot freely relative to the support 11. On the other hand, in the locked mode MODV, the locking finger 25 is in the channel 22 to restrict the pivoting. In another aspect, the locking finger 25 may include a fusible region 270 for security.

[0065] To control the movement of the locking finger 25, the locking system 20 may include a control 30. The control 30 may include a human-machine interface 31, which can be operated by an operator to control the movement system. The movement system may include at least one cable capable of translational movement, or, for example, a ball control 33, at least one set wheel 34, a resilient connecting rod 35, an actuator 37, etc.

[0066] exist Figure 3 In the moving system, a cable 33 is connected to a handle 31, the cable 33 slides in a sheath 32 and is connected to a resilient connecting rod 35 via a lever 36, the resilient connecting rod 35 being connected to a locking finger 25.

[0067] Alternatively and according to Figures 4 to 8 The example shown includes a human-machine interface 31 that is wired or wirelessly connected to an electric actuator 37, which is capable of translating or rotating the locking finger 25.

[0068] Regardless of the method of moving the locking finger 25 and referring to Figure 3 The aircraft 1 includes a monitoring system 50 and a processing system 60. The monitoring system 50 is configured to determine the presence of a risk of sudden yaw motion of the aircraft 1 when the locking finger 25 is in the MODV lock mode on the ground and the pivot landing gear 10 is unlocked, and to send a risk signal to the processing system 60 after determining that there is a risk of sudden yaw motion.

[0069] Therefore, the method according to the present invention includes the following steps:

[0070] • During step STP2 and using monitoring system 50, it is determined whether there is a risk of sudden yaw motion of aircraft 1 during takeoff or when pivot landing gear 10 is unlocked, when locking finger 25 is in locked mode MODV; and

[0071] • And if present, a risk signal is sent to the processing system 60 during step STP3 using the monitoring system 50.

[0072] The processing system 60 may include an alarm generator 61 linked to the monitoring system 50 via a wired or wireless link. The alarm generator 61 functions specifically to generate an alarm upon receiving a risk signal. Each alarm may be in the form of a visual alarm, such as emitting light using a light-emitting diode or equivalent, or one or more characters displayed on a screen, an audible alarm via a speaker, and / or a tactile alarm, such as vibrating a component held or worn by a person via a vibration unit.

[0073] In a complementary or alternative manner, the processing system 60 may include a suppressor 70 linked to the monitoring system 50 via a wired or wireless link. The suppressor 70 functions to block the locking finger 25 upon request in the MODV (Mount of Detention) lock mode. For example, the suppressor 70 includes a locking actuator 71 capable of holding the locking finger 25 in the MODV lock mode upon command. Specifically, in the presence of a mechanical motion system, such a locking actuator 71 may, for example, brake or block the locking finger 25 or a component of the control 30 that moves the locking finger 25 by form interference. In the presence of a locking finger 25 controlled by a locking actuator, the locking actuator 71 may suppress the locking actuator, for example, by electrically cutting off the power line to the electric locking actuator via a relay, or by closing the valve supplying the hydraulic locking actuator.

[0074] According to another aspect, the aircraft 1 may include an alert generator 62 that is wired or wirelessly connected to the monitoring system 50. The monitoring system 50 is then configured to generate an alert signal and send it to the alert generator 62 before issuing a risk signal. As a result, the alert generator 62 then issues an alert. Each alert may be in the form of a visual alert, such as using a light-emitting diode or equivalent or one or more characters displayed on a screen, an audible alert via a speaker, and / or a tactile alert, such as vibrating a component held or worn by an individual by means of a vibration unit. The alert generator 62 and the alarm generator 61 may be a single device and may be capable of performing other functions.

[0075] In order to generate risk signals or even warning signals, according to Figures 3 to 8 The monitoring system 50 is configured to evaluate a force-related value relative to a limit in the locking system 20 during step STP1. Therefore, the monitoring system 50 is configured to determine the risk of the sudden yaw motion when the value exceeds a limit, and optionally generate an alert if the value is between a threshold and the limit.

[0076] Therefore, according to Figures 3 to 7For example, the monitoring system 50 may include at least one sensor 40 for measuring the value and a controller 55. The sensor 40 sends a measurement signal carrying the value to the controller 55, which determines whether the value is greater than a limit and thus generates the risk signal, or even determines whether the value is between the threshold and the limit, and then generates an alert signal.

[0077] The term "sensor" should be understood to refer to a physical sensor capable of directly measuring the parameter in question, and to a system that may include one or more physical sensors, as well as means for processing signals such that estimates of the parameter can be provided based on the measurements provided by these physical sensors. Similarly, the concept of a measured parameter refers to both the raw measurement from the physical sensor and the measurement obtained through relatively complex processing of the raw measurement signal.

[0078] In addition, controller 55 includes a processing unit. In this specification, the term "processing unit" refers to a component that may include, for example, at least one processor and at least one memory, at least one integrated circuit, at least one programmable system, and at least one logic circuit; these examples do not limit the scope to the term "processing unit." The term "processor" may be equivalently referred to as a central processing unit or CPU, a graphics processing unit or GPU, a digital signal processor or DSP, a microcontroller, etc.

[0079] Therefore, according to Figure 3 For example, the monitoring system 50 may include a sensor 40 with at least one stress measuring instrument 41 arranged on a locking finger 25. In the illustrated case, the locking finger 25 is inserted into a channel 22 along an axis AXT substantially parallel to the pivot axis AXP. Therefore, the stress measuring instrument 41 can be positioned on one or more sides of the locking finger 25. Each stress measuring instrument 41 then communicates with a controller 55, which is configured to send a risk signal indicating a risk of stability loss to a processing system 60 when a measured value VM obtained using the sensor 40 exceeds a stored limit LIM.

[0080] Regardless of the nature of the sensor, Figure 3 The possibility of having a suppressor 70 is illustrated, which is provided with an electric or other locking actuator 71 that moves a fixed finger 73 capable of blocking the locking finger 25 by shape interference in the locked position. For example, when the suppressor 70 is active, the fixed finger 73 contacts the shoulder of the locking finger 25 to prevent the locking finger 25 from being removed from the channel 22.

[0081] Figure 4 It shows the relationship with Figure 3 The same type of sensor 40 and suppressor 70 are used. On the other hand, with... Figure 3 To create a contrast, Figure 4 The possibility of radially introducing the locking finger 25 into the channel 22 via the pivot AXP is illustrated. In this case, the stress measuring instrument 41 can be placed on the top or bottom of the locking finger 25 to measure the mirror value of the shear force borne by the locking finger 25. Figure 4 Also shown is a control 30 with an interface 31 that controls an electric actuator 37 to move a locking finger 25.

[0082] according to Figure 5 As an example, the suppressor 70 is provided with a locking actuator 71 that suppresses the electric actuator 37 used for locking the control 30. According to the example shown, the locking actuator 71 electrically isolates the electric actuator 37 from the power supply 370 that powers it.

[0083] according to Figure 6 For example, sensor 40 may include an integrated sensing bearing 42 that guides locking fingers 25, the integrated sensing bearing 42 including at least one stress meter 41 that measures the mirror value of the force applied to the integrated sensing bearing 42 by the locking fingers 25. Regardless of the nature of the sensor, Figure 6 The possibility of having a suppressor 70 is shown, which is provided with a locking actuator 71 of the electric actuator 37 of the suppression control.

[0084] and Figure 6 To create a contrast, Figure 7 An equivalent variation is shown, in which a locking finger 25 is provided in a channel of the support 21 that is radially inserted relative to the pivot axis AXP.

[0085] according to Figure 8 In the example shown, sensor 40 may include two warning microswitches 43 disposed on either side of locking finger 25 and, in the illustrated example, in a plane perpendicular to pivot axis AXP. Alternatively, locking system 50 may also include two warning microswitches 90 disposed on either side of locking finger 25 to generate a warning. Warning microswitches 43 may communicate with controller 55 of control processing system 60, or may send signals directly to processing system 60. Similarly, warning microswitches 90 may communicate with controller 55, or may send signals directly to warning generator 62.

[0086] according to Figure 9In another alternative described herein, monitoring system 50 includes a position sensor 95 that measures the current position of yaw control 97 of aircraft 1 and a velocity sensor 96 that measures the current rotational speed of lift rotor 4 of aircraft 1, or even includes a complementary sensor 92 that measures the current position of component 91 used to control the total pitch of the blades of lift rotor 4. Monitoring system 50 may include a detection sensor 99 for assessing whether the aircraft is on the ground, for example, by evaluating the pressure in landing gear 10 or the position of landing gear. Monitoring system 50 includes a controller 55 that communicates with position sensor 95 and velocity sensor 96, or even detection sensor 99 and complementary sensor 92. Controller 55 is then configured to issue a risk signal based on the current position and current rotational speed, or even the signal from detection sensor 99 and / or the position of control 91, so as to issue a risk signal when aircraft 1 is on the ground.

[0087] According to a variant, controller 55 uses, for example, stored laws to determine the current yaw moment based on the current position and current rotational speed of yaw control 97, or even the position of control 91. If the current yaw moment exceeds a stored limit moment, or if sensor 99 simultaneously detects measurements indicating the aircraft's position on the ground, controller 55 generates a risk signal.

[0088] According to a variant, controller 55 uses, for example, a stored law to determine the current yaw moment based solely on the current position of yaw control 97, or based on the current position of yaw control 97 and the position of control 91. Controller 55 is then configured to issue a risk signal if the current yaw moment exceeds a limit moment, and if this is combined with the current rotational speed exceeding a predetermined speed threshold, or if this is combined with measurements from detection sensor 99 indicating the aircraft's position on the ground.

[0089] Naturally, the invention can undergo many variations in its implementation. Although several embodiments have been described above, it should be readily understood that it is not conceivable to exhaustively characterize all possible embodiments. Of course, any of the described devices can be replaced with equivalent devices without departing from the scope of the invention and the claims.

[0090] For example, the various implementation methods described above can be combined, possibly by using a sensor described in one figure with a suppressor and / or control described in another figure, and / or by modifying the position of the support and locking fingers.

Claims

1. An aircraft (1) having a pivot landing gear (10) having a support (11) and a pivot assembly (12) for carrying a contact member (15) configured to contact the ground (100), the pivot assembly (12) being rotatable relative to the support (11) about a pivot axis (AXP), the pivot landing gear (10) having a pivot locking system (20) including a base (21) contains a channel (22) and a movable locking finger (25), the locking finger (25) being located outside the channel (22) in unlocked mode (MODDV) to allow the pivot assembly (12) to pivot freely relative to the support (11), the locking finger (25) being placed in the channel (22) in locked mode (MODV) to restrict the pivoting, the locking finger (25) being carried by the support (11), and the base (21) being part of the pivot assembly (12). in, The aircraft (1) includes a monitoring system (50) configured to determine the presence of a risk of sudden yaw motion of the aircraft (1) when the locking finger (25) is in the locked mode (MODV) on the ground, during takeoff or unlocking of the pivot landing gear (10), the monitoring system (50) being configured to send a risk signal to a processing system (60) after determining the presence of the risk of sudden yaw motion, the monitoring system (50) being configured to determine the presence of the risk of sudden yaw motion when a value related to the force in the locking system (20) is greater than a limit, the monitoring system (50) including at least one sensor (40) for measuring the value and a controller (55), the sensor (40) sending a measurement signal carrying the value to the controller (55), the controller (55) being configured to determine whether the value is greater than the limit, thereby generating the risk signal.

2. The aircraft according to claim 1, in, The sensor (40) includes at least one stress measuring instrument (41) arranged on the locking finger (25) and measuring the value, wherein the force is a shear force applied to the locking finger (25).

3. The aircraft according to claim 1, in, The sensor (40) includes an integrated sensing bearing (42) that guides a locking finger (25) and measures the value, the force being applied to the integrated sensing bearing (42) by the locking finger (25).

4. An aircraft (1) having a pivot landing gear (10) having a support (11) and a pivot assembly (12) for carrying a contact member (15) configured to contact the ground (100), the pivot assembly (12) being rotatable relative to the support (11) about a pivot axis (AXP), the pivot landing gear (10) having a pivot locking system (20) including a base (21) contains a channel (22) and a movable locking finger (25), the locking finger (25) being located outside the channel (22) in unlocked mode (MODDV) to allow the pivot assembly (12) to pivot freely relative to the support (11), the locking finger (25) being placed in the channel (22) in locked mode (MODV) to restrict the pivoting, the locking finger (25) being carried by the support (11), and the base (21) being part of the pivot assembly (12). in, The aircraft (1) includes a monitoring system (50) configured to determine the presence of a risk of sudden yaw motion of the aircraft (1) during takeoff or unlocking of the pivot landing gear (10) when the locking finger (25) is in the locked mode (MODV) on the ground. The monitoring system (50) is configured to send a risk signal to a processing system (60) after determining the presence of a risk of sudden yaw motion. The monitoring system (50) is also configured to determine the presence of a sudden yaw motion when a value related to the force in the locking system (20) exceeds a limit. However, to mitigate the risk of yaw motion, the monitoring system (50) includes at least two alarm microswitches (43) disposed on either side of the locking finger (25). When the pivot assembly (12) pivots relative to the support in one direction, an alarm microswitch (43) is activated when the value exceeds the limit. Each activated alarm microswitch emits an alarm signal indicating a risk signal sent to the processing system (60) or the alarm signal is sent to the controller (55), whereby the controller (55) issues the risk signal.

5. An aircraft (1) having a pivot landing gear (10) having a support (11) and a pivot assembly (12) for carrying a contact member (15) configured to contact the ground (100), the pivot assembly (12) being rotatable relative to the support (11) about a pivot axis (AXP), the pivot landing gear (10) having a pivot locking system (20) including a base (21) contains a channel (22) and a movable locking finger (25), the locking finger (25) being located outside the channel (22) in unlocked mode (MODDV) to allow the pivot assembly (12) to pivot freely relative to the support (11), the locking finger (25) being placed in the channel (22) in locked mode (MODV) to restrict the pivoting, the locking finger (25) being carried by the support (11), and the base (21) being part of the pivot assembly (12). in, The aircraft (1) includes a monitoring system (50) configured to determine the presence of a risk of sudden yaw motion of the aircraft (1) when the locking finger (25) is in the locked mode (MODV) on the ground, during takeoff or unlocking of the pivot landing gear (10). The monitoring system (50) is configured to issue a risk signal to a processing system (60) after determining the presence of a risk of sudden yaw motion. The monitoring system (50) includes a position sensor (95) measuring the current position of the yaw control (97) of the aircraft and a speed sensor measuring the current rotational speed of the lift rotor (4) of the aircraft. 96), the monitoring system (50) includes a controller (55) communicating with the position sensor (95) and the speed sensor (96), the controller (55) being configured to issue the risk signal at least based on the current position and the current rotational speed, the controller (55) being configured to estimate the current yaw moment based on the current position and the current rotational speed, or based on the current position and the current rotational speed and the position of the component (91) for controlling the total pitch of the blades of the lifting rotor (4) as measured using a complementary sensor (92), and to generate the risk signal if the current yaw moment is greater than the limit moment.

6. An aircraft (1) having a pivot landing gear (10) having a support (11) and a pivot assembly (12) having the pivot assembly (12) carrying a contact member (15) configured to contact the ground (100), the pivot assembly (12) being rotatable relative to the support (11) about a pivot axis (AXP), the pivot landing gear (10) having a pivot locking system (20) including a base (21) contains a channel (22) and a movable locking finger (25), the locking finger (25) being located outside the channel (22) in unlocked mode (MODDV) to allow the pivot assembly (12) to pivot freely relative to the support (11), the locking finger (25) being placed in the channel (22) in locked mode (MODV) to restrict the pivoting, the locking finger (25) being carried by the support (11), and the base (21) being part of the pivot assembly (12). in, The aircraft (1) includes a monitoring system (50) configured to determine the presence of a risk of sudden yaw motion of the aircraft (1) when the locking finger (25) is in the locked mode (MODV) on the ground, during takeoff or unlocking of the pivot landing gear (10). The monitoring system (50) is configured to send a risk signal to a processing system (60) after determining the presence of a risk of sudden yaw motion. The monitoring system (50) includes a position sensor (95) measuring the current position of the yaw control (97) of the aircraft and a speed sensor (96) measuring the current rotational speed of the lift rotor (4) of the aircraft. The monitoring system (50) includes a controller (55) communicating with the position sensor (95) and the speed sensor (96), the controller (55) being configured to issue the risk signal based at least on the current position and the current rotational speed, the controller (55) being configured to determine the current yaw moment based solely on the current position, or based on the current position and the position of a component (91) for controlling the total pitch of the blades of the lift rotor (4) as measured using a complementary sensor (92), the controller being configured to generate the risk signal if the current yaw moment is greater than a limit moment and if the current rotational speed is greater than a predetermined speed threshold.

7. The aircraft according to claim 1, in, The aircraft (1) includes an auxiliary landing gear (8) and two main landing gears (7), the pivot landing gear (10) forming the auxiliary landing gear (8).

8. The aircraft according to claim 1, in, The processing system (60) includes an alarm generator (61) that generates an alarm after receiving the risk signal.

9. The aircraft according to claim 1, in, The processing system (60) includes a suppressor (70) that holds the locking finger (25) in the locking mode (MODV) after receiving the risk signal.

10. The aircraft according to claim 9, in, The suppressor (70) includes a locking actuator (71) that holds the locking finger (25) in the locked mode (MODV) by interfering with the shape of the locking finger (25) or a control (30) that controls the movement of the locking finger (25), or by suppressing such control (30).

Images