A high sea state landing gear limiting capability evaluation method and a landing gear

Abstract

The present application relates to the technical field of helicopter landing gear design, and particularly relates to a high sea state landing gear limiting capacity evaluation method, comprising the following steps: establishing a helicopter normal parking state balance equation set; establishing a helicopter critical overturning state balance equation set; the stable moment is equal to the overturning moment at the critical state, and a stable moment-overturning moment balance equation is established; the three aforementioned equation sets are solved simultaneously to obtain a single landing gear load of the helicopter in the normal parking state and the critical overturning state; the displacement compression amount of the buffer is obtained according to the single landing gear load and the buffer load-compression amount curve; the difference between the buffer displacement compression amounts in the normal parking state and the critical overturning state is taken as the displacement limiting value of the landing gear under the action of the limiter; the helicopter is tested in the high sea state, the extension and retraction amount of the main landing gear buffer is measured; and the extension and retraction amount is compared with the displacement limiting value.

Description

Technical Field

[0001] This invention belongs to the field of helicopter landing gear design technology, and particularly relates to a method for evaluating the limiting capability of landing gear in high sea state and a landing gear design. Background Technology

[0002] When a ship is sailing or stationary at sea, helicopters parked on board will be subject to swaying due to waves and wind. The landing gear's dampers absorb landing energy and reduce impact loads, and their design allows for retractable movement. Since shipborne helicopters need to be towed or moored on board, if landing gear movement causes the helicopter to tilt or generate impacts, it poses a certain danger to the helicopter's operation. Therefore, it is necessary to design a limiting method for the helicopter landing gear and assess its limiting capability under high sea states to determine whether the shipborne helicopter meets safety requirements under high sea state disturbances.

[0003] Currently, there are no mature methods or design criteria for assessing the landing gear limiting capabilities of helicopters operating from ships in high sea states. Therefore, a method for assessing landing gear limiting capabilities in high sea states is needed to analyze the landing gear limiting capabilities of shipborne helicopters in order to determine whether the safety of shipborne helicopters under high sea state disturbances meets the requirements. Summary of the Invention

[0004] Purpose of the invention: To overcome the shortcomings of the prior art and realize the assessment of the limiting capability of helicopter landing gear in high sea state, this invention designs a method for assessing the limiting capability of landing gear in high sea state and a landing gear.

[0005] Technical solution

[0006] A method for assessing the limiting capability of landing gear in high sea state includes the following steps:

[0007] Step 1: Establish the equilibrium equations for the normal shutdown state of the helicopter;

[0008] Step 2: Establish the equilibrium equations for the critical overturning state of the helicopter;

[0009] Step 3: At the critical state, the stabilizing moment equals the overturning moment, and the equilibrium equation of stabilizing moment and overturning moment is established;

[0010] Step 4: Solve the three equations mentioned above to determine the load on a single landing gear of the helicopter in both normal parking and critical overturning states;

[0011] Step 5: Obtain the displacement compression of the buffer based on the load-compression curve of the individual landing gear load and the buffer.

[0012] Step 6: Use the difference in buffer displacement compression between the normal shutdown state and the critical overturning state as the displacement limit value of the landing gear under the action of the limit switch.

[0013] Step 7: With limiters installed, conduct a high sea state test on the helicopter to measure the extension and retraction of the main landing gear buffers; and compare the extension and retraction with the displacement limit value.

[0014] If the displacement limit is exceeded, the landing gear limiter is considered to have insufficient limiting capacity; otherwise, the landing gear limiter is considered to have qualified limiting capacity.

[0015] Furthermore, in step one, moments are taken about the parallel X-axis line passing through the left main landing gear contact point B, and moments are also taken about the parallel Y-axis line passing through the tail landing gear contact point C, establishing the following set of equilibrium equations for the normal shutdown state:

[0016] F A0 +F B0 +F C0 -mg=0

[0017] F C0 ×1 / 2L AB +F A0 ×L AB -mg×L GB =0

[0018] F A0 ×L AC cosa+F B0 ×L BC cosa-mg×L GC =0

[0019] F A0 =F B0

[0020] L GB =1 / 2L AB

[0021] in,

[0022] F A0 The load on the right main landing gear under normal shutdown conditions, F B0 The load on the left main landing gear under normal shutdown conditions, F C0 The tail landing gear load is under normal shutdown conditions; m is the helicopter mass, L AB L is the distance between the right and left main landing gears. AC L is the distance between the right main landing gear and the tail landing gear. BC L is the distance between the left main landing gear and the tail landing gear. GB L is the perpendicular distance along the X-axis between the center of gravity before the offset and point B of the left main landing gear. GCL0 is the vertical distance between the forward center of gravity and point C of the over-tail landing gear along the Y-axis; L0 is the length of the left (or right) main landing gear buffer at full extension; and a is the angle between the roll axis and the helicopter heading.

[0023] Furthermore, in step two, when the helicopter is affected by sea conditions, the center of gravity shifts due to differences in landing gear compression, causing the helicopter to tilt to one side. When the helicopter is in a critical overturning state, it tilts along the axis AC connecting the main landing gear contact point A and the tail landing gear contact point C. Taking moments about the line passing through the main landing gear point A and perpendicular to the tilt axis AC, the following set of equilibrium equations for the critical overturning state is established:

[0024] F A +F C -n Z mg = 0

[0025] F C ×L AC +n Z mg×L G1 -F f ×H1-n xy mg×H1=0

[0026] Among them, F A For the right main landing gear load under critical overturning conditions, F C The tail landing gear load under critical overturning conditions; n Z For the inertial overload of the vertical ship deck, L G1 n is the straight-line distance from the offset center of gravity to the axis AC passing through point A and perpendicular to the roll axis; xy F is the overload factor perpendicular to the roll axis AC. f H1 represents the wind load perpendicular to the tilt axis, and H1 is the vertical height of the center of gravity relative to the deck after the offset.

[0027] Furthermore, in step three,

[0028] Stabilizing torque, M0 = n Z ×mg×L G1

[0029] Overturning moment, M1 = n xy mg H1+F f H1

[0030] The equilibrium equations for stabilizing moment and overturning moment are as follows:

[0031] n Z ×mg×L G1 =n xy mg H1+F f H1

[0032] The geometric relationships are as follows:

[0033] n xy =n x sina+n y cosa

[0034] F f＝ F fx sina+F fy cosa

[0035] Where, n x and n y M0 represents the inertial overload components along the X and Y axes; M1 represents the stabilizing moment; and F represents the overturning moment. fx and F fy These are the components of wind load along the X and Y axes in the ship's coordinate system;

[0036] Furthermore, in step four, the main landing gear load F under normal shutdown conditions is obtained. A0 Tail landing gear load F C0 ;

[0037] Main landing gear load F under critical overturning conditions A Tail landing gear load F C .

[0038] Furthermore, in step five, the buffer load-compression curve is obtained from the static pressure test of the landing gear buffer:

[0039] Main landing gear damper compression S under normal shutdown conditions A0 Tail landing gear buffer compression S C0 ;

[0040] Main landing gear buffer compression S under critical overturning conditions A Tail landing gear buffer compression S C .

[0041] Furthermore, in step six,

[0042] Maximum compression displacement limit ΔS of main landing gear limiter A =S A0 -S A ;

[0043] Maximum tensile displacement limit L0-S of main landing gear limiter A0 ;

[0044] The maximum displacement limit ΔS of the tail landing gear limiter C =S C0 -S C .

[0045] Furthermore, in step seven, if the stretching or compression of the tail landing gear buffer exceeds the maximum displacement limit of the tail landing gear limiter, then the tail landing gear limiter is considered to have insufficient limiting capability.

[0046] If the compression of the main landing gear buffer exceeds the maximum compression displacement limit of the main landing gear limiter, or if the extension of the main landing gear buffer exceeds the maximum extension displacement limit of the main landing gear limiter, then the main landing gear limiter is deemed to have insufficient limiting capability.

[0047] A helicopter landing gear includes a limiter, the limiting capability of which is evaluated by the method described.

[0048] Beneficial effects

[0049] This invention solves the problem of difficulty in assessing the landing gear limit capability of shipborne helicopters at sea; it can ensure the reliability and safety of helicopters operating at sea; the assessment method is simple and suitable for general aviation professionals. Attached Figure Description

[0050] Figure 1 This is a diagram illustrating helicopters docking on ships in high sea states.

[0051] Figure 2 This is a diagram showing the geometric positional relationship of the landing gear;

[0052] Figure 3 This is a schematic diagram illustrating the shift in the center of gravity caused by the different compression levels of the left and right landing gears.

[0053] Figure 4 A schematic diagram showing the relationship between the three landing gears and the center of gravity;

[0054] Figure 5 This is a schematic diagram showing the connection relationship of the limit device;

[0055] Figure 6 This is a schematic diagram illustrating inconsistent landing gear compression.

[0056] 1. Main landing gear, 2. Main landing gear limiter, 3. Tail landing gear, 4. Tail landing gear limiter. Detailed Implementation

[0057] This invention provides a method for evaluating the limiting capability of landing gear in high sea states. By constructing a method for calculating the attitude stability of helicopters under the action of high sea state waves and winds, the maximum value of the change in the length of the landing gear buffer is calculated when the helicopter attitude stability boundary is reached. The displacement value that the helicopter landing gear can extend and retract under the restriction of the limiter is compared with this maximum value. In this way, the method evaluates whether the landing gear of a shipborne helicopter can maintain attitude stability and safety under the restriction of the limiter under high sea state conditions, that is, whether the limiting capability of the helicopter landing gear is qualified.

[0058] The specific method is as follows:

[0059] Under the influence of sea conditions, helicopters are affected by factors such as ship swaying motion and wind load, which will generate helicopter overturning moment. The helicopter's own weight provides stabilizing moment. When the helicopter is in a critical overturning state (i.e., the boundary of the stable state), the stabilizing moment is close to equal to the overturning moment, forming equation (8). Combine the mechanical analysis equations (1)-(5) of the helicopter in the normal stopping state (not affected by sea conditions) and the mechanical analysis equations (6)-(7) of the helicopter in the critical overturning state to obtain the load of a single landing gear in the normal stopping state and the critical overturning state of the helicopter. Then, the displacement compression of the buffer is obtained according to the buffer load-compression curve. The difference in the compression of the buffer in the normal stopping state and the critical overturning state of the helicopter is used as the displacement limit value of the landing gear under the action of the limiter. If the displacement of the helicopter landing gear still exceeds this displacement limit value after the limiter is installed, it is determined that the helicopter landing gear limit capability is insufficient.

[0060] The ship's deck coordinate system where the helicopter is located is as follows: Figure 1 As shown, the X-axis represents the reverse direction of the helicopter's flight path, the Y-axis represents the reverse direction of the helicopter's flight path from point B on the left main landing gear to point A on the right landing gear, and the Z-axis represents the vertical plane facing upwards.

[0061] Since this design is for a tricycle landing gear configuration, in the critical overturning state, the load on the right main landing gear and the left main landing gear is inconsistent, resulting in inconsistent compression of their shock absorbers. That is, the lengths of the right main landing gear and the left main landing gear are inconsistent. Therefore, the main landing gear limiters have two values: compression displacement and tension displacement. However, the tail landing gear only has one value, and the length change of the landing gear has only one value. The tail landing gear limiters have only one displacement value.

[0062] (a) For the helicopter in a normal stopped state (not subjected to sea state loads), the equilibrium equations are as follows:

[0063] F A0 +F B0 +F C0 -mg=0 (1)

[0064] (Take the moment about the line parallel to the X-axis passing through point B of the left main landing gear)

[0065] F C0 ×1 / 2L AB +F A0 ×L AB -mg×L GB =0 (2)

[0066] (Take the moment about the parallel Y-axis line passing through point C of the tail landing gear)

[0067] FA0 ×L AC cosα+F B0 ×L BC cosα-mg×L GC =0 (3)

[0068] F A0 =F B0 (4)

[0069] L GB =1 / 2 L AB (5)

[0070] (b) When the helicopter is subjected to sea state effects, the different compression amounts of the landing gear cause the center of gravity of the helicopter to shift, and the helicopter will tilt to one side( Figure 3 ), the center of gravity changes from point G to point G1. When the helicopter is in the critical overturning state: the helicopter tilts along the axis AC(BC) which is the line connecting the main landing gear contact point A(B) and the tail landing gear contact point C. The equilibrium equation is established as follows:

[0071] F A +F C -n Z mg=0 (6)

[0072] (Taking moments about the straight line passing through point A of the main landing gear and perpendicular to the tilting axis AC, as shown in Figure 4 )

[0073] F C ×L AC +n Z mg×L G1 -F f ×H1-n xy mg×H1=0(7)

[0074] (c) The z-direction inertial overload provides a stabilizing moment M0, and the xy-direction inertial overload and wind load provide an overturning moment M1; when the stabilizing moment M0 is less than M1, the helicopter is at risk of overturning.

[0075] Stabilizing moment, M0=n Z ×mg×L G1

[0076] Overturning moment, M1=n xy mg H1+F f H1

[0077] In the critical state, M0=M1; that is, n Z ×mg×L G1 =n xy mg H1+F f H1 (8)

[0078] From geometric relations: n xy =n x sina+n y cosa (9)

[0079] F f＝ F fx sina+F fy cosa (10)

[0080] (d) Solve the equations in (1)-(10) simultaneously.

[0081] Solve for the landing gear load F A0 (F A0 =F B0 ) and F C0 Then, the landing gear buffer compression S is obtained from the curve corresponding to the landing gear buffer compression and load (static pressure curve). A0 (S A0 =S B0 ), S C0 .

[0082] Solving for the landing gear load F under critical overturning conditions A and F C Then, the landing gear buffer compression S is obtained from the curve corresponding to the landing gear buffer compression and load (static pressure curve). A S C .

[0083] From ΔS A =S A0 -S A Maximum compression displacement limit of main landing gear limiter, ΔS C =S C0 -S C The maximum displacement limit of the tail landing gear limiter is ΔS. A L0-S A0 ΔS C As an evaluation value for the limiting capability of helicopter landing gear; if the tensile displacement length of the main landing gear exceeds L0-S under high sea state conditions after being limited by the limiter. A0 Compression displacement exceeds ΔS A The tail landing gear, after being limited by the limit switch, has a displacement length exceeding ΔS under high sea state conditions. C If any one of the above conditions is met, the landing gear's limiting capability under the limit device is deemed insufficient.

[0084] In the formula, F A0 The load on the right main landing gear under normal shutdown conditions, F B0 The load on the left main landing gear under normal shutdown conditions, F C0 The tail landing gear load is under normal shutdown conditions; FA For the right main landing gear load under critical overturning conditions, F C The tail landing gear load under critical overturning conditions; L AB L is the distance between the right and left main landing gears. AC L is the distance between the right main landing gear and the tail landing gear. BC L is the distance between the left main landing gear and the tail landing gear. GB L is the perpendicular distance along the X-axis between the center of gravity before the offset and point B of the left main landing gear. GC L0 is the perpendicular distance along the Y-axis between the forward center of gravity and point C of the over-tail landing gear; L0 is the length of the left (or right) main landing gear damper at full extension; a is the angle between the roll axis and the helicopter's heading; m is the helicopter's mass; n Z For the inertial overload of the vertical ship deck, L G1 n is the straight-line distance from the offset center of gravity to the axis AC passing through point A and perpendicular to the roll axis; xy n is the overload factor perpendicular to the roll axis AC. x and n y M0 represents the inertial overload components along the X and Y axes; M1 represents the stabilizing moment; and F represents the overturning moment. f For wind load perpendicular to the tilt axis, F fx and F fy Let be the wind load components along the X and Y axes in the ship's coordinate system; H1 is the vertical height of the offset center of gravity relative to the deck; m, a, L AB L AC L BC L0, n x and n y F fx and F fy The quantity is known.

[0085] Design and composition of limit device

[0086] Limiting devices are a general term for various displacement limiters, and can be composed of multiple limiters. Figure 4 This invention provides limiting protection for helicopter landing gear, preventing the helicopter from capsizing under high sea state conditions on ships or other water platforms. Specifically designed for a tailwheel helicopter landing gear configuration, the limiting device includes two main landing gear limiters and one tail landing gear limiter. The limiting device can withstand various specified operating loads and extreme combinations of limit loads after considering safety factors without experiencing strength failure. The design limiting load is obtained from the inertial forces and wind loads acting on the helicopter due to ship motion. The limiting device structure has good rigidity, mechanically limiting the landing gear length. After being limited by the limiting device, the helicopter on board maintains its attitude stability. An installation joint is provided at the landing gear mounting location, and a displacement limiter is installed on the installation joint. The limiter includes a main rod, with movable screws installed at both ends of the main rod.

[0087] Determining the limiter's ultimate load and length;

[0088] When the helicopter on the ship is subjected to sea conditions, the maximum load on the main landing gear under overload is N1. At this time, the compression of the main landing gear is obtained according to the buffer load-compression curve, and then the spacing T1 of the limiter mounting interface on the main landing gear is calculated. The main landing gear stopping load under the minimum weight state of the helicopter is N2 (that is, the minimum stopping load of the main landing gear). At this time, the compression of the main landing gear is obtained according to the buffer load-compression curve, and then the spacing T2 of the limiter mounting interface on the main landing gear is calculated.

[0089] The difference between loads N1 and N2, N3 = N1 - N2, is the maximum limit of the compressive load borne by the main landing gear limiter. Considering a certain safety factor, the compressive load for the limiter strength design is n1 N3. The minimum load of the main landing gear under sea state overload is N4. The main landing gear stopping load under the maximum weight state of the helicopter main landing gear is N5 (i.e., the maximum stopping load of the main landing gear). The difference between N5 and N4, N6 = N5 - N4, is the maximum limit of the tensile load of the main landing gear limiter. Considering a certain safety factor, the tensile load for the limiter strength design is n2N5. The coefficients n1 and n2 are taken as 1.1-1.5 based on engineering design experience.

[0090] When the helicopter on the ship is affected by sea conditions, the maximum load on the tail landing gear under overload is M1. At this time, the compression of the tail landing gear is obtained according to the buffer load-compression curve, and then the spacing T3 of the limiter mounting interface on the tail landing gear is calculated. The tail landing stop load under the minimum weight state of the helicopter is M2 (that is, the minimum stop load of the tail landing gear). At this time, the compression of the tail landing gear is obtained according to the buffer load-compression curve, and then the spacing T4 of the limiter mounting interface on the tail landing gear is calculated.

[0091] The difference between M1 and M2, M3 = M1 - M2, represents the maximum compressive load that the tail landing gear limiter can withstand. Considering a certain safety factor, the compressive load for the limiter strength design is taken as n3M3. The minimum load of the tail landing gear under sea state overload is M4. The tail landing gear stopping load under the maximum weight state of the helicopter tail landing gear is M5 (i.e., the maximum stopping load of the tail landing gear). The difference between M5 and M4, M6 = M5 - M4, represents the maximum tensile load that the tail landing gear limiter can withstand. Considering a certain safety factor, the tensile load for the limiter strength design is taken as n4M5. The coefficients n3 and n4 are taken as 1.1-1.5 based on engineering design experience.

[0092] The loads n1 and n3, n2 and N5 are the compressive load limit and tensile load limit of the main landing gear limiter under strength design, respectively; T1 and T2 are the maximum and minimum limit lengths of the main landing gear limiter under design, respectively, meaning the main landing gear limiter is adjustable within the length range of T1-T2; the loads n3 and n4 are the compressive load limit and tensile load limit of the tail landing gear limiter under strength design, respectively; T3 and T4 are the maximum and minimum limit lengths of the tail landing gear limiter under design, respectively, meaning the tail landing gear limiter is adjustable within the length range of T3-T4.

[0093] Key points of this invention:

[0094] By constructing a method for calculating the attitude stability of helicopters under the influence of high sea state waves and sea winds, the maximum value of the change in landing gear buffer length is calculated when the helicopter attitude stability boundary is reached.

[0095] By combining the equations that the stabilizing moment equals the overturning moment, the mechanical analysis equations for the helicopter in its normal stopping state, and the mechanical analysis equations for the helicopter in its critical overturning state, the displacement compression of a single landing gear buffer in both the normal stopping state and the critical overturning state can be obtained.

[0096] The limiting capability of the limiter is evaluated by comparing the displacement length of the limiter under high sea state conditions with the limiter's displacement limit length.

[0097] Limiting devices are a general term for various displacement limiters. They can consist of multiple limiters and provide limiting protection for helicopter landing gear.

[0098] An installation joint is provided at the landing gear mounting location, and a displacement limiter is provided on the installation joint. The limiter includes a main rod, and movable screws are installed at the upper and lower ends of the main rod.

[0099] The main landing gear compression is obtained from the main landing gear buffer load-compression curve, and then the spacing of the limit switch mounting interfaces on the main landing gear is obtained.

[0100] The tail landing gear compression is obtained from the tail landing gear buffer load-compression curve, and then the spacing of the limiter mounting interface on the tail landing gear is obtained.

[0101] The above description is merely a preferred embodiment of the present invention, used only to illustrate the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the original intent of the invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for evaluating the limiting capability of landing gear in high sea state, characterized in that: The method includes the following steps: Step 1: Take moments about the parallel X-axis line passing through the left main landing gear contact point B, and about the parallel Y-axis line passing through the tail landing gear contact point C, to establish the following set of equilibrium equations for the helicopter in normal parking condition: F A0 + F B0 +F C0 -mg=0 F C0 ×1 / 2L AB + F A0 ×L AB -mg×L GB =0 F A0 ×L AC what+ F B0 ×L BC what -mg×L GC =0 F A0 = F B0 L GB =1 / 2 L AB F A0 The load on the right main landing gear under normal shutdown conditions, F B0 The load on the left main landing gear under normal shutdown conditions, F C0 The tail landing gear load is under normal shutdown conditions; m is the helicopter mass, L AB L is the distance between the right and left main landing gears. AC L is the distance between the right main landing gear and the tail landing gear. BC L is the distance between the left main landing gear and the tail landing gear. GB L is the perpendicular distance along the X-axis between the center of gravity before the offset and point B of the left main landing gear. GC L0 is the perpendicular distance between the forward center of gravity and point C of the over-tail landing gear on the Y-axis; L0 is the length of the left or right main landing gear damper at full extension; a is the angle between the roll axis and the helicopter heading; g is the acceleration due to gravity. Step 2: The helicopter tilts along axis AC, which connects the main landing gear contact point A and the tail landing gear contact point C. Taking moments about a line passing through point A of the main landing gear and perpendicular to the tilt axis AC, the following set of equilibrium equations for the helicopter's critical overturning state is established: F A + F C -n Z mg=0 F C ×L AC +n Z mg×L G1 -F f ×H1-n xy mg×H1=0 Among them, F A For the right main landing gear load under critical overturning conditions, F C The tail landing gear load under critical overturning conditions; n Z For the inertial overload of the vertical ship deck, L G1 n is the straight-line distance from the offset center of gravity to the axis AC passing through point A and perpendicular to the roll axis; xy F is the overload factor perpendicular to the roll axis AC. f The wind load is perpendicular to the tilt axis, and H1 is the vertical height of the center of gravity relative to the deck after the offset. Step 3: At the critical state, the stabilizing moment equals the overturning moment. The equilibrium equation between the stabilizing moment and the overturning moment is established as follows: Stabilizing torque, M0=n Z ×mg×L G1 Overturning moment, M1=n xy mg H1+F f H1 The equilibrium equations for stabilizing moment and overturning moment are as follows: n Z ×mg×L G1 =n xy mg H1+F f H1 The geometric relationships are as follows: n xy = n x mona+n y thing F f= F fx sina+F fy what in, and M0 represents the inertial overload components along the X and Y axes; M1 represents the stabilizing moment; and F represents the overturning moment. fx and F fy These are the components of wind load along the X and Y axes in the ship's coordinate system; Step 4: Solve the three equations mentioned above to determine the load on a single landing gear of the helicopter in both normal parking and critical overturning states; Step 5: Obtain the displacement compression of the buffer based on the load-compression curve of the individual landing gear load and the buffer. Step 6: Use the difference in buffer displacement compression between the normal shutdown state and the critical overturning state as the displacement limit value of the landing gear under the action of the limit switch. Step 7: With limiters installed, conduct a high sea state test on the helicopter to measure the extension and retraction of the landing gear buffers; and compare the extension and retraction with the displacement limit value. If the displacement limit is exceeded, the landing gear limiter is considered to have insufficient limiting capacity; otherwise, the landing gear limiter is considered to have qualified limiting capacity.

2. The method according to claim 1, characterized in that: In step two, when the helicopter is affected by sea conditions, the helicopter's center of gravity shifts due to the different landing gear compression, causing the helicopter to tilt to one side and reach a critical overturning state.

3. The method according to claim 1, characterized in that: In step four, the main landing gear load F under normal shutdown conditions is obtained. A0 Tail landing gear load F C0 ; Main landing gear load F under critical overturning conditions A Tail landing gear load F C .

4. The method according to claim 1, characterized in that: In step five, the buffer load-compression curve is obtained from the static pressure test of the landing gear buffer: Main landing gear damper compression S under normal shutdown conditions A0 Tail landing gear buffer compression S C0 ; Main landing gear buffer compression S under critical overturning conditions A Tail landing gear buffer compression S C .

5. The method according to claim 4, characterized in that: In step six, Maximum compression displacement limit ΔS of main landing gear limiter A =S A0 -S A ; Maximum tensile displacement limit L0-S of main landing gear limiter A0 ; The maximum displacement limit ΔS of the tail landing gear limiter C =S C0 -S C .

6. The method according to claim 5, characterized in that: In step seven, if the stretching or compression of the tail landing gear buffer exceeds the maximum displacement limit of the tail landing gear limiter, then the tail landing gear limiter is considered to have insufficient limiting capability. If the compression of the main landing gear buffer exceeds the maximum compression displacement limit of the main landing gear limiter, or if the extension of the main landing gear buffer exceeds the maximum extension displacement limit of the main landing gear limiter, then the main landing gear limiter is deemed to have insufficient limiting capability.

7. A helicopter landing gear, characterized in that: The landing gear includes a limiter, the limiting capability of which is evaluated by the method described in any one of claims 1-6.

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