Single-rotor tail rotor failure disposal determination method for a tail rotor of a helicopter
Patent Information
- Application Number
- CN202510418146.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2026-10-16
AI Technical Summary
[0005]本发明解决现有技术中尾桨故障部分状态无法验证的问题，提出一种单旋翼带尾桨直升机尾桨故障处置程序的确定方法，用于分析直升机尾桨故障状态下的响应、控制方法和处置程序，降低直接试飞的风险
[0034]本发明提出一种尾桨故障状态下的分析方法，依据目标直升机尾桨故障的各种模式，通过分析故障后能够继续飞行、操纵和着陆的飞行状态，以及状态转换能力，能够在试飞前提供理论参考。本方法可降低直接进行试飞的风险，能够为应急处置程序的制定提供依据。
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Figure CN122915408A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flight mechanics technology, and in particular relates to a method for determining the fault handling of the tail rotor of a single-rotor helicopter with a tail rotor. Background Technology
[0002] The tail rotor is one of the main control surfaces of a single-rotor helicopter with a tail rotor, responsible for providing directional trim capability, directional stability, and maneuverability. If the tail rotor fails, the helicopter will be in a state of severe stress imbalance, which, without effective countermeasures, could lead to catastrophic loss of life and the aircraft. To address potential risks, it is necessary to analyze the modes of tail rotor failure, their consequences, and corresponding countermeasures during the design phase, and to determine emergency response procedures.
[0003] Tail rotor failure can be categorized into two modes: tail rotor control failure and tail rotor failure. In the case of tail rotor failure, if thrust is lost, the helicopter rotor's counter-torque cannot be balanced. To ensure the helicopter's maneuverability and stability, the pilot needs to disconnect the engine from the main rotor and initiate autorotation. In the case of tail rotor control failure, the tail rotor can still provide some force after the failure, but this force is uncontrollable. Therefore, special piloting skills and flight conditions are required to ensure a safe landing. Because tail rotor failure can occur at multiple stages of helicopter flight, it usually requires maintaining balance or making adjustments through sideslip or autorotation. If an acceptable flight condition cannot be achieved, restrictions need to be placed on the flight conditions during a tail rotor failure.
[0004] Since the condition of a tail rotor failure cannot be verified, this invention can calculate the helicopter's flight status before the tail rotor failure test flight verification, in order to formulate the handling procedures in case of a tail rotor failure. Summary of the Invention
[0005] This invention addresses the problem that the state of a tail rotor failure cannot be verified in the prior art. It proposes a method for determining the handling procedure for a single-rotor helicopter with a tail rotor failure, which is used to analyze the response, control method and handling procedure under the failure state of the helicopter tail rotor, thereby reducing the risk of direct test flight.
[0006] To achieve the above objectives, the present invention employs the following technical solution.
[0007] A method for determining tail rotor failure in a single-rotor helicopter with a tail rotor, the method comprising:
[0008] S1, determine the helicopter's flight status when the tail rotor fails;
[0009] S2, confirms that the helicopter can maintain a balanced flight state after multiple tail rotor failures.
[0010] S3, determine the stability of a flight state that can maintain balance;
[0011] S4. If the stability requirements are met, calculate the handling and maneuverability of the helicopter that can maintain the trim flight state.
[0012] If the stability requirements are not met, return to S3 to determine the stability of the next flight state that can maintain the balance, until all flight states that can maintain the balance are determined, and the handling and maneuverability of the helicopter are obtained for all flight states that can maintain the balance.
[0013] S5 determines whether the helicopter's handling and maneuverability are sufficient for landing in all flight states that can maintain balance.
[0014] S6 selects a flight state with landing capability as the helicopter tail rotor failure handling procedure.
[0015] Furthermore, S1 specifically refers to:
[0016] The limitations on rotor speed, flight altitude, and flight speed during tail rotor failure are determined, as well as the tail rotor failure mode, which includes: tail rotor control failure and tail rotor malfunction.
[0017] Furthermore, S2 specifically refers to:
[0018] When the tail rotor fails, the helicopter's flight state is hovering. The calculations are made of the ability to continue hovering, the ability to descend at a small rate of descent, the ability to climb forward, and the ability to land vertically with the engines shut down, in order to obtain the flight state that can maintain trim. A small rate of descent refers to a descent rate of less than 2.4 m / s.
[0019] Furthermore, S2 specifically refers to:
[0020] When the tail rotor fails, the helicopter's flight status is as follows: calculate the ability to fly forward and rotate at a small descent rate; a small descent rate refers to a descent rate of less than 2.4 m / s.
[0021] Furthermore, S2 specifically refers to:
[0022] When the tail rotor fails, the helicopter's flight state is climbing. Calculate the hovering capability and the vertical descent capability at a small descent rate; a small descent rate refers to a descent rate of less than 2.4 m / s.
[0023] Furthermore, S2 specifically refers to:
[0024] When the tail rotor fails, the helicopter's flight state is turning and sideslipping. Calculate the sideslipping flight capability and forward flight capability.
[0025] Furthermore, S2 specifically refers to:
[0026] When the helicopter is in a glide state due to tail rotor failure, calculate its ability to maintain a stable glide after the tail rotor failure occurs.
[0027] Furthermore, S2 specifically refers to:
[0028] When the helicopter is in a state of autorotation due to tail rotor failure, calculate its ability to maintain stable autorotation when the tail rotor failure occurs.
[0029] Furthermore, in S4, the handling and maneuverability of the helicopter capable of maintaining trim flight state are calculated, specifically as follows:
[0030] By applying lateral control to the flight state that can maintain trim, the helicopter can achieve the expected heading response, and thus obtain the corresponding attitude and speed responses.
[0031] Furthermore, the S5's landing capability means:
[0032] The speed response allows the forward velocity to decrease to below the landing speed limit with a descent rate of less than 2.4 m / s;
[0033] Attitude response enables the helicopter to align its heading with the runway.
[0034] This invention proposes an analysis method for tail rotor failure states. Based on various tail rotor failure modes of the target helicopter, it analyzes the flight states that allow continued flight, control, and landing after the failure, as well as the state transition capabilities, providing theoretical reference before test flights. This method can reduce the risks of directly conducting test flights and can provide a basis for the development of emergency response procedures. Attached Figure Description
[0035] Figure 1 This is a flowchart illustrating a method for determining tail rotor faults in a single-rotor helicopter with a tail rotor, provided in an embodiment of the present invention.
[0036] Figure 2 This is a schematic diagram illustrating the relationship between yaw rate and descent rate during helicopter landing, provided as an embodiment of the present invention. Detailed Implementation
[0037] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.
[0038] This invention proposes a method for determining the handling procedure for tail rotor failure in a single-rotor helicopter with a tail rotor. This method is used to analyze the response, control methods, and handling procedures under tail rotor failure conditions, thereby reducing the risk of direct test flights.
[0039] This invention provides a method for determining tail rotor failure in a single-rotor helicopter with a tail rotor, the method comprising:
[0040] S1, determine the helicopter's flight status when the tail rotor fails;
[0041] S2, confirms that the helicopter can maintain a balanced flight state after multiple tail rotor failures.
[0042] S3, determine the stability of a flight state that can maintain balance;
[0043] S4. If the stability requirements are met, calculate the handling and maneuverability of the helicopter that can maintain the trim flight state.
[0044] If the stability requirements are not met, return to S3 to determine the stability of the next flight state that can maintain the balance, until all flight states that can maintain the balance are determined, and the handling and maneuverability of the helicopter are obtained for all flight states that can maintain the balance.
[0045] S5 determines whether the helicopter's handling and maneuverability are sufficient for landing in all flight states that can maintain balance.
[0046] S6 selects a flight state with landing capability as the helicopter tail rotor failure handling procedure.
[0047] S1, specifically: determining the usage limits of rotor speed, flight altitude, and flight speed when the tail rotor fails, as well as the tail rotor failure mode, which includes: tail rotor control failure and tail rotor malfunction.
[0048] S2, specifically: when the helicopter is hovering due to tail rotor failure, calculate the ability to continue hovering, the ability to descend at a small rate of descent, the ability to climb forward, and the ability to land vertically with the engines shut down, to obtain a flight state that can maintain trim; small rate of descent refers to a descent rate of less than 2.4 m / s.
[0049] S2, specifically: when the tail rotor fails and the helicopter's flight state is takeoff, calculate the ability to fly forward and rotate at a small descent rate; small descent rate refers to a descent rate of less than 2.4 m / s.
[0050] S2, specifically: when the helicopter is climbing due to a tail rotor failure, calculate the hovering capability and the vertical descent capability at a small descent rate; a small descent rate refers to a descent rate of less than 2.4 m / s.
[0051] S2, specifically: when the helicopter's flight state is turning and sideslipping due to tail rotor failure, calculate sideslipping flight capability and forward flight capability.
[0052] S2, specifically: when the helicopter is in a glide state due to a tail rotor failure, calculate the ability to maintain a stable glide after the tail rotor failure occurs.
[0053] S2, specifically: when the helicopter's flight state is autorotation due to tail rotor failure, calculate the ability to maintain stable autorotation when tail rotor failure occurs.
[0054] In S4, the handling and maneuverability of the helicopter capable of maintaining trim flight state are calculated, specifically as follows:
[0055] By applying lateral control to the flight state that can maintain trim, the helicopter can achieve the expected heading response, and thus obtain the corresponding attitude and speed responses.
[0056] S5, having landing capability means that the speed response allows the forward flight speed to decrease to below the landing speed limit with a descent rate of less than 2.4 m / s;
[0057] Attitude response enables the helicopter to align its heading with the runway.
[0058] Specifically, the technical solutions adopted in this invention and the verification objectives are shown in Appendix 1 and Appendix 2. Figure 1 It includes the following steps:
[0059] Step 1: Determine the helicopter's flight status when the tail rotor fails. This step is to determine the operating conditions for subsequent analysis. Generally, the state parameters to be determined include rotor speed, altitude, speed, and other operating limits, as well as the tail rotor failure mode (including tail rotor control failure and tail rotor failure).
[0060] Step Two: Determine the helicopter's ability to maintain trim flight status after tail rotor failure. This involves trimming the helicopter to a specified stable flight state, then setting the tail rotor to various failure states. Analysis demonstrates the helicopter's ability to maintain a similar flight state and clarifies the flyable range, ensuring safe helicopter flight and providing time and space for intervention. The specified stable and similar flight states include:
[0061] (1) Hovering. Calculate the ability to continue hovering, the ability to descend vertically at a low rate of descent (less than 2.4 m / s), the ability to fly forward at a low rate of climb, and the ability to land vertically with the engines off; taking vertical descent as an example (see Appendix). Figure 2 The trim relationship between the descent rate and the yaw rate can be calculated.
[0062] (2) Takeoff. Calculate the flight capability and autorotation capability before the small descent rate;
[0063] (3) Climbing. Calculate hovering ability and descent ability at small descent rates (descent rate less than 2.4 m / s);
[0064] (4) Turning and sideslipping. Calculate sideslipping flight capability and forward flight capability;
[0065] (5) Glide slope. Calculate the ability to maintain a stable glide slope after a tail rotor failure;
[0066] (6) Rotation. Calculate the ability of the tail rotor to maintain stable rotation after a tail rotor failure.
[0067] Step 3: Determine the stability of the flight state maintaining trim flight after tail rotor failure. The method is as follows: calculate the trim state under tail rotor failure, linearize the state, obtain the eigenvalues of the linearized model (see Appendix Table 1), and determine the stability.
[0068] Table 1. Stability after sideslip trim in case of tail rotor failure (example)
[0069]
[0070] Step 4: Calculate the helicopter's handling and maneuverability to maintain a trimmed flight state. After a tail rotor failure, alternative control methods (e.g., lateral control) should be available to achieve directional control. The analysis method is as follows: Under the trimmed state of a tail rotor failure, apply collective pitch control, lateral control, longitudinal control, or a combination thereof to achieve the expected directional response of the helicopter, thus obtaining the corresponding attitude and speed responses.
[0071] Step 5: Determine whether the handling and maneuverability are sufficient for a safe landing.
[0072] The specific criterion is: through combined maneuvers before landing, the helicopter's maneuverability can reach the following level just before touchdown:
[0073] (1) The speed response enables the helicopter to reduce its speed to below the landing speed limit;
[0074] (2) At this time, the helicopter's descent rate is less than 2.4 m / s;
[0075] (3) Attitude response enables the helicopter to align with the runway.
[0076] Step Six: Select a flight state capable of landing, and the combined control method before touchdown, as the procedure for handling helicopter tail rotor failure.
[0077] This invention proposes an analysis method for tail rotor failure states. Based on various tail rotor failure modes of the target helicopter, it analyzes the flight states that allow continued flight, control, and landing after the failure, as well as the state transition capabilities, providing theoretical reference before test flights. This method can reduce the risks of directly conducting test flights and can provide a basis for the development of emergency response procedures.
Claims
1. A method for determining tail rotor faults in a single-rotor helicopter with a tail rotor, characterized in that, The method includes: S1, determine the helicopter's flight status when the tail rotor fails; S2, confirms that the helicopter can maintain a balanced flight state after multiple tail rotor failures. S3, determine the stability of a flight state that can maintain balance; S4. If the stability requirements are met, calculate the handling and maneuverability of the helicopter that can maintain the trim flight state. If the stability requirements are not met, return to S3 to determine the stability of the next flight state that can maintain the balance, until all flight states that can maintain the balance are determined, and the handling and maneuverability of the helicopter are obtained for all flight states that can maintain the balance. S5 determines whether the helicopter's handling and maneuverability are sufficient for landing in all flight states that can maintain balance. S6 selects a flight state with landing capability as the helicopter tail rotor failure handling procedure.
2. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S1, specifically: The limitations on rotor speed, flight altitude, and flight speed during tail rotor failure are determined, as well as the tail rotor failure mode, which includes: tail rotor control failure and tail rotor malfunction.
3. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S2, specifically: When the tail rotor fails, the helicopter's flight state is hovering. The calculations are made of the ability to continue hovering, the ability to descend at a small rate of descent, the ability to climb forward, and the ability to land vertically with the engines shut down, in order to obtain the flight state that can maintain trim. A small rate of descent refers to a descent rate of less than 2.4 m / s.
4. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S2, specifically: When the tail rotor fails, the helicopter's flight status is as follows: calculate the ability to fly forward and rotate at a small descent rate; a small descent rate refers to a descent rate of less than 2.4 m / s.
5. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S2, specifically: When the tail rotor fails, the helicopter's flight state is climbing. Calculate the hovering capability and the vertical descent capability at a small descent rate; a small descent rate refers to a descent rate of less than 2.4 m / s.
6. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S2, specifically: When the tail rotor fails, the helicopter's flight state is turning and sideslipping. Calculate the sideslipping flight capability and forward flight capability.
7. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S2, specifically: When the helicopter is in a glide state due to tail rotor failure, calculate its ability to maintain a stable glide after the tail rotor failure occurs.
8. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S2, specifically: When the helicopter is in a state of autorotation due to tail rotor failure, calculate its ability to maintain stable autorotation when the tail rotor failure occurs.
9. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, In S4, the handling and maneuverability of the helicopter capable of maintaining trim flight state are calculated, specifically as follows: By applying lateral control to the flight state that can maintain trim, the helicopter can achieve the expected heading response, and thus obtain the corresponding attitude and speed responses.
10. The method for determining tail rotor faults in a single-rotor helicopter with a tail rotor according to claim 1, characterized in that, S5, having landing capability means: The speed response allows the forward velocity to decrease to below the landing speed limit with a descent rate of less than 2.4 m / s; Attitude response enables the helicopter to align its heading with the runway.