A seaplane hull stabilization device and design method thereof

Abstract

The present invention belongs to the technical field of seaplane design and discloses a seaplane hull stabilization device and a design method thereof. The device comprises a transverse member, a longitudinal member, and a wall panel. The transverse member is divided into a front transverse member and a rear transverse member. The front transverse member is transversely arranged at a designed step position on the seaplane hull bottom. The rear transverse member is transversely arranged longitudinally rearward of the step surface on the seaplane hull bottom. The rear transverse member forms a new step position on the seaplane hull bottom. The front and rear transverse members are connected by transversely spaced longitudinal members. The wall panel is arranged at the bottom of the transverse and longitudinal members and forms the hull bottom shape of the seaplane. The present invention can shift the hull step position rearward, shifting the hydrodynamic action point rearward during high-speed gliding of the seaplane, thereby improving the heading stability of the seaplane during high-speed gliding. This does not require reversing the previous hull line design, significantly shortening the improvement cycle and cost.

Description

Technical Field

[0001] The invention belongs to the technical field of seaplane design, and relates to a device for improving the hull structure of a seaplane, and in particular to a hull stabilization device for a seaplane and a design method thereof. Background Art

[0002] During the high-speed taxiing phase before takeoff, a seaplane relies primarily on the section of the hull preceding the step to glide on the water. However, a seaplane's center of gravity is typically high, creating a certain attitude angle during taxiing. This reduces the distance between the center of gravity and the step, leading to directional instability during high-speed taxiing. Furthermore, the seaplane is subject to the influence of its longitudinal stability boundary, requiring control of the attitude angle before takeoff, and requiring a higher liftoff speed to achieve liftoff.

[0003] During seaplane takeoff, landing, and taxiing, directional and longitudinal stability significantly impact aircraft safety. Therefore, measures are necessary to improve directional stability during high-speed taxiing and increase the longitudinal stability margin, thereby enhancing directional and longitudinal control capabilities and making seaplanes safer during water takeoff. During the design phase of a seaplane, comprehensive adjustments to the overall hull's linear parameters are typically made to achieve good directional and longitudinal stability. However, comprehensive adjustments to the hull's linear parameters during production and flight testing significantly extend the development cycle, making this unacceptable. Furthermore, some localized hull appendages often only improve certain aspects of the hull's performance. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a seaplane hull stabilization device and a design method thereof. By supplementing a seaplane whose hull line shape is already completely fixed, the directional stability and longitudinal stability boundary range of the installed seaplane during high-speed gliding on the water surface can be significantly increased. The device is easy to install and easy to implement.

[0005] The technical solutions of the present invention are as follows:

[0006] A seaplane hull stabilization device includes a transverse member, a longitudinal member, and a wall plate member. The transverse member is divided into a front transverse member and a rear transverse member. The front transverse member is transversely arranged at a designed step position on the bottom of the seaplane hull. The rear transverse member is transversely arranged longitudinally rearward of the step surface on the bottom of the seaplane hull. The rear transverse member forms a new step position on the bottom of the seaplane hull. The front transverse member and the rear transverse member are connected by longitudinal members arranged at intervals on the transverse side. The wall plate member is arranged at the bottom of the transverse and longitudinal members and serves as the outer shape of the bottom of the seaplane hull.

[0007] Furthermore, the front transverse member is a V-shaped transverse structure, the top shape of the front transverse member matches the shape of the designed stepped position on the bottom of the seaplane hull, and the front transverse member is fixedly connected to the bottom of the seaplane hull.

[0008] Furthermore, the heights of both ends of the front transverse member are consistent with the heights of the bilge line of the front hull of the seaplane.

[0009] Furthermore, the rear cross member is a V-shaped connected cross structure, the height of the rear cross member is higher than the front cross member, the top shape of the rear cross member matches the shape of the bottom of the rear body of the seaplane hull, and the rear cross member is connected to the bottom of the rear body of the seaplane hull through a connecting member.

[0010] Furthermore, the heights of both ends of the rear transverse member are consistent with the heights of the bilge line of the rear hull of the seaplane.

[0011] Furthermore, the longitudinal members include a keel longitudinal member connected to the keel of the seaplane hull, a stringer longitudinal member connected to the stringer of the seaplane hull, and a bilge longitudinal member connected to the bilge line of the seaplane hull. The shapes of the keel longitudinal member, the stringer longitudinal member and the bilge longitudinal member respectively match the shapes of the keel, stringer and bilge line of the seaplane hull.

[0012] Furthermore, a hull stabilizing device is installed behind the seaplane: the hull step position of the seaplane is moved rearward, and the distance from the position of the hull step after the step is moved rearward to the center of gravity is not greater than 0.3 times the bilge width of the hull; the ratio of the rear body to the front body is reduced, and the length ratio of the rear body to the front body of the seaplane is not less than 1.15:1; the step height is increased, and the step height is not greater than 0.08 times the bilge width of the hull; the deadrise angle is reduced, so that the deadrise angle is within 20°-35°.

[0013] A method for designing a seaplane hull stabilization device, used for designing the above-mentioned seaplane hull stabilization device, comprises the following steps:

[0014] S1, design of initial seaplane hull stabilization device;

[0015] S2, installing the initial seaplane hull stabilization device on the seaplane hull and performing computational analysis or testing on the seaplane;

[0016] S3, adjusting the longitudinal front-to-back position of the rear transverse member according to the calculated analysis structure or test results.

[0017] Furthermore, S3 is specifically as follows: if the improvement in the heading or longitudinal stability of the seaplane hull is insufficient, the position of the rear cross member is adjusted to move it longitudinally rearward, and the length of the longitudinal member is adaptively adjusted; if the impact on water resistance, longitudinal maneuverability or water load exceeds a warning threshold, the position of the rear cross member is adjusted to move it longitudinally forward, and the length of the longitudinal member is adaptively adjusted.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The device of the present invention moves the step position of the hull backward, so that the hydrodynamic action point of the seaplane during high-speed gliding moves backward, thereby improving the heading stability of the seaplane during high-speed gliding.

[0020] 2. Through the device of the present invention, the ratio of the rear body to the front body is reduced, the rear body is shortened, the nose-down moment generated by the rear body of the hull is reduced, and a larger upper limit of longitudinal stability can be obtained; at the same time, the front body is increased, the front body splash coefficient is reduced, and the splash characteristics can be further improved.

[0021] 3. The device of the present invention increases the height of the steps, making it easier for the rear body to ventilate, making it less likely for the rear body to be adsorbed at high speeds, thus avoiding the "dolphin movement" and further increasing the upper limit of longitudinal stability.

[0022] 4. The device of the present invention reduces the ramp angle, thereby increasing the gliding efficiency of the forebody when gliding on the water surface at high speed. At the same time, the forebody generates a greater lifting moment, which can increase the lower limit of longitudinal stability.

[0023] 5. By changing the above parameters, the heading stability of the seaplane during high-speed gliding is mainly improved and the longitudinal stability boundary range is increased. At the same time, the aircraft's water-leaving speed is reduced and the splash characteristics of the aircraft's front body are improved. By controlling the longitudinal position of the rear cross member, the longitudinal control ability, water resistance and water load increase of the seaplane during gliding on the water surface are kept within an acceptable range.

[0024] 6. The device of the present invention can be directly installed on a seaplane with a determined hull shape, without negating the previous hull line design, which greatly shortens the improvement cycle and improvement cost, and the effect after improvement is almost the same as that of redesigning the hull line. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 The figure is a schematic diagram of a seaplane hull stabilization device according to an embodiment of the present invention.

[0027] Figure 2 This is a diagram showing the installation position layout of the stabilization device according to an embodiment of the present invention.

[0028] Figure 3 This is a side view of a stabilization device according to an embodiment of the present invention.

[0029] Figure 4 It is a rear view of the stabilization device according to an embodiment of the present invention.

[0030] Figure 5 It is a bottom view of the stabilization device according to an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of analyzing the change in the hydrodynamic action point after the device is installed in an embodiment of the present invention.

[0032] Figure 7 This is a boundary analysis diagram of the longitudinal stability of high-speed gliding on the water surface after the device is installed in the embodiment of the present invention.

[0033] In the figure, 1 is a horizontal member, 2 is a longitudinal member, 3 is a wall panel member, and 4 is a connecting member. DETAILED DESCRIPTION

[0034] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships for the purposes of the accompanying drawings, and are intended only to facilitate the description of the present invention and simplify the description, rather than to indicate or imply that the device or case referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first", "second" and the like are used for descriptive purposes only, and should not be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second" and the like may explicitly or implicitly include more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0036] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they may refer to fixed, detachable, or integrated connections; mechanical or point connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] Example 1:

[0038] A seaplane hull stabilization device includes a transverse member 1, a longitudinal member 2, and a wall panel member 3. The transverse member 1 is divided into a front transverse member and a rear transverse member. The front transverse member is transversely arranged at a designed stepped position on the bottom of the seaplane hull. The rear transverse member is transversely arranged longitudinally rearward of the stepped surface on the bottom of the seaplane hull. The rear transverse member forms a new stepped position on the bottom of the seaplane hull. The front and rear transverse members are connected by longitudinal members 2 arranged at intervals in the transverse direction. The wall panel member 3 is arranged at the bottom of the transverse member 1 and the longitudinal member 2 and serves as the outer shape of the bottom of the seaplane hull.

[0039] The forward transverse member is a V-shaped transverse structure. The top profile of the forward transverse member matches the profile of the designed stepped portion of the seaplane's hull bottom. The forward transverse member is fixedly connected to the seaplane's hull bottom. The height of the forward transverse member's ends matches the height of the seaplane's forebody's bilge line.

[0040] The rear cross member is a V-shaped transverse structure. It is taller than the front cross member. Its top shape matches the bottom shape of the rear hull of the seaplane. The rear cross member is connected to the bottom of the rear hull of the seaplane via connector 4. The heights of both ends of the rear cross member match the height of the bilge line of the rear hull of the seaplane.

[0041] The longitudinal members 2 include a keel longitudinal member connected to the keel of the seaplane hull, a stringer longitudinal member connected to the stringer of the seaplane hull, and a bilge longitudinal member connected to the bilge line of the seaplane hull. The shapes of the keel longitudinal member, the stringer longitudinal member and the bilge longitudinal member respectively match the shapes of the keel, stringer and bilge line of the seaplane hull.

[0042] The hull stabilizing device is installed behind the seaplane: the hull step position of the seaplane is moved rearward, and the distance from the position of the hull step after the step is moved rearward to the center of gravity is not greater than 0.3 times the hull bilge width; the length ratio of the rear body to the front body is reduced, and the length ratio of the rear body to the front body of the seaplane is not less than 1.15:1; the step height is increased, and the step height is not greater than 0.08 times the hull bilge width; the deadrise angle is reduced, and the deadrise angle is within 20°-35°.

[0043] A method for designing a seaplane hull stabilization device, used for designing the aforementioned seaplane hull stabilization device, comprises the following steps:

[0044] S1, design of initial seaplane hull stabilization device;

[0045] S2, installing the initial seaplane hull stabilization device on the seaplane hull and performing computational analysis or testing on the seaplane;

[0046] S3, adjusting the longitudinal front-to-back position of the rear transverse member according to the calculation analysis structure or test results.

[0047] S3 is specifically as follows: if the improvement in the heading or longitudinal stability of the seaplane hull is insufficient, the position of the rear cross member is adjusted to move it longitudinally rearward, and the length of the longitudinal member is adaptively adjusted; if the impact on water resistance, longitudinal maneuverability or water load exceeds the warning threshold, the position of the rear cross member is adjusted to move it longitudinally forward, and the length of the longitudinal member is adaptively adjusted.

[0048] Example 2:

[0049] A seaplane hull stabilization device comprises a transverse member 1, longitudinal members 2, paneling members 3, and connectors 4, and is bilaterally symmetrical. The forward transverse member 1 is connected to the original hull step, while the rearward transverse member 1 is connected to the original hull frame or other transverse structure via connectors 4. The fore-aft position of the rearward transverse member 1 can be adjusted based on the required water surface stability and the structural installation conditions. If, through calculation, analysis, or testing, the heading or longitudinal stability is insufficiently improved, the rearward transverse member 1 is moved rearward; if it has an unacceptable impact on water resistance, longitudinal maneuverability, or water load, the rearward transverse member 1 is moved forward. The longitudinal members 2 are respectively connected to the transverse member 1 and the original longitudinal structures of the hull, such as the keel, bilge, and spars. The paneling members 3 are connected to the transverse member 1 and the longitudinal members 2 to maintain the bottom shape of the hull.

[0050] The longitudinal position of the rear cross member 1 can be adjusted according to the water surface planing stability requirements and the structural installation conditions, thereby changing the main parameters of the hull: the hull step position is moved rearward, the ratio of the rear body to the front body is reduced, the step height is increased, and the deadrise angle is reduced.

[0051] By shifting the hull step aft, the hydrodynamic point of action for a seaplane during high-speed taxiing is shifted aft, improving its directional stability. This shift also increases the burden of longitudinal maneuvering, requiring computational analysis or testing to verify that longitudinal maneuverability is acceptable while improving directional stability. Generally, the distance from the aft hull step to the center of gravity should not exceed 0.3 times the bilge width.

[0052] By reducing the aft-to-forebody ratio and shortening the aft body, the nose-down moment generated by the aft body is reduced, achieving a greater upper limit of longitudinal stability. Simultaneously, by increasing the forebody, the forebody splash coefficient is reduced, further improving splash characteristics. A reduction in the aft-to-forebody ratio also increases the water resistance of the seaplane as it glides on the water. Calculations, analysis, or testing are required to verify that the seaplane has sufficient residual acceleration after overcoming the water resistance to achieve a water takeoff. Generally, the aft-to-forebody ratio should not be less than 1.15:1.

[0053] Increasing the step height allows for easier ventilation of the rear hull, preventing it from adsorbing at high speeds, thus avoiding "dolphin maneuvers" and further increasing the upper limit of longitudinal stability. Increasing the step height also increases the water resistance of the seaplane as it glides on the water. Computational analysis or testing is required to verify that the seaplane has sufficient residual acceleration after overcoming the water resistance to achieve a water takeoff. Generally, the step height should not be greater than 0.08 times the bilge width of the ship.

[0054] Reducing the deadrise angle increases the forebody's gliding efficiency during high-speed water taxiing, while also generating a greater nose-up moment, thereby increasing the lower limit of longitudinal stability. This also increases the water load during water taxiing. A deadrise angle of approximately 25° is generally recommended. If the aircraft's landing speed is slow, the deadrise angle can be appropriately reduced; if it is fast, it can be increased. The typical range is 20°-35°.

[0055] By changing these parameters, the heading stability of the seaplane during high-speed gliding is mainly improved and the longitudinal stability boundary range is increased. At the same time, the aircraft's water-leaving speed is reduced, the splash characteristics of the aircraft's front body are improved, and by controlling the longitudinal position of the rear cross member, the increase in the seaplane's longitudinal control ability, water resistance and water load when gliding on the water surface is kept within an acceptable range. Figure 6 In order to analyze the change of the hydrodynamic action point after installing this device, the analysis was conducted from different gliding postures. After installing this device, the hydrodynamic action point of the hull gliding on the water surface moved backward, which increased the heading stability when gliding on the water surface.

[0056] Figure 7 In order to analyze the longitudinal stability boundary of high-speed gliding on the water surface after installing this device, through the analysis of the longitudinal stability boundary of gliding on the water surface at different speeds, after installing this device, the lower longitudinal stability boundary moves upward slightly, but the upward movement is not large. The upward movement of the upper longitudinal stability boundary can obtain a larger attitude angle, and the entire longitudinal stability boundary range becomes larger.

[0057] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made within the scope of the patent application of the present invention still fall within the scope covered by the invention.

Claims

1. A hull stabilization device for a seaplane, characterized in that: The invention comprises a transverse member (1), a longitudinal member (2) and a wall member (3), wherein the transverse member (1) is divided into a front transverse member and a rear transverse member, wherein the front transverse member is transversely arranged at a designed step position of the bottom of the hull of the seaplane, and the rear transverse member is transversely arranged longitudinally rearward of the step surface of the bottom of the hull of the seaplane, wherein the rear transverse member forms a new step position of the bottom of the hull of the seaplane, and the front transverse member and the rear transverse member are connected by longitudinal members (2) arranged transversely at intervals, and the wall member (3) is arranged at the bottom of the transverse member (1) and the longitudinal member (2) and serves as the bottom shape of the hull of the seaplane; The front transverse member is a V-shaped transverse structure, the top shape of the front transverse member matches the shape of the designed stepped position on the bottom of the seaplane hull, and the front transverse member is fixedly connected to the bottom of the seaplane hull; The rear transverse member is a V-shaped transverse structure, the height of the rear transverse member is higher than the front transverse member, the top shape of the rear transverse member matches the shape of the bottom of the rear body of the seaplane hull, and the rear transverse member is connected to the bottom of the rear body of the seaplane hull through a connecting member (4); The longitudinal member (2) includes a keel longitudinal member connected to the keel of the seaplane hull, a stringer longitudinal member connected to the stringer of the seaplane hull, and a bilge longitudinal member connected to the bilge line of the seaplane hull, and the shapes of the keel longitudinal member, the stringer longitudinal member and the bilge longitudinal member respectively match the shapes of the keel, stringer and bilge line of the seaplane hull; The hull stabilizing device is installed behind the seaplane: the hull step position of the seaplane is moved rearward, the length ratio of the rear hull to the front hull of the seaplane is reduced, the hull step height of the seaplane is increased, and the hull inclined angle of the seaplane is reduced.

2. The seaplane hull stabilization device according to claim 1, characterized in that: The heights of both ends of the front transverse member are consistent with the height of the bilge line of the front hull of the seaplane.

3. The seaplane hull stabilization device according to claim 1, characterized in that: The heights of both ends of the rear transverse member are consistent with the height of the bilge line of the rear hull of the seaplane.

4. The seaplane hull stabilization device according to claim 1, characterized in that: The hull stabilizing device is installed behind the seaplane: the distance from the rearward position of the seaplane's hull step to the center of gravity is not greater than 0.3 times the hull bilge width; the length ratio of the seaplane's rear hull to the front hull is not less than 1.15:1; the height of the seaplane's hull step is not greater than 0.08 times the hull bilge width; the seaplane's hull deadrise angle is within 20°-35°.

5. A method for designing a seaplane hull stabilization device, for designing a seaplane hull stabilization device according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, design of initial seaplane hull stabilization device; S2, installing the initial seaplane hull stabilization device on the seaplane hull and performing computational analysis or testing on the seaplane; S3, adjusting the longitudinal front-to-back position of the rear transverse member according to the calculated analysis structure or test results.

6. The method for designing a seaplane hull stabilization device according to claim 5, characterized in that: S3 is specifically as follows: if the improvement in the heading or longitudinal stability of the seaplane hull is insufficient, the position of the rear cross member is adjusted to move it longitudinally rearward, and the length of the longitudinal member is adaptively adjusted; if the impact on water resistance, longitudinal maneuverability or water load exceeds the warning threshold, the position of the rear cross member is adjusted to move it longitudinally forward, and the length of the longitudinal member is adaptively adjusted.

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