A method for calculating the weight and balance of water ingress into the watertight compartment of a large seaplane

Abstract

This invention proposes a method for calculating the water ingress weight and balance of a seaplane's watertight compartment, comprising: S1, determining the allowable value Δx for the safe center of gravity margin; S2, determining the relationship between the center of gravity of each watertight compartment and the empty aircraft's center of gravity, dividing the watertight compartment center of gravity into two datasets: before and after the empty aircraft's center of gravity; S3, determining the volume factor ratio of each watertight compartment relative to a reference watertight compartment based on the determined external volume of the watertight compartment; S4, using the volume factor ratio and the dataset obtained in step 2, conducting an analysis of the water ingress weight and balance before and after the empty aircraft's center of gravity until the allowable value Δx for the safe center of gravity margin is met; S5, selecting the water ingress volume of watertight compartment (1) that is greater than and closest to the engineering realization value as the final water ingress volume value, and calculating the allowable water ingress volume of the remaining watertight compartments; S6, determining the final weight and balance analysis results of the watertight compartments, ensuring that the allowable water ingress volume of each watertight compartment meets the requirement of the allowable value Δx for the safe center of gravity margin. This application enhances the safety and reliability of amphibious aircraft during waterborne test flights and operations.

Description

Technical Field

[0001] This invention relates to a method for calculating the weight and balance of water entering the watertight compartment of a large seaplane. This method can calculate and determine the weight distribution data of water entering the watertight compartment of a seaplane that meets the requirements for load and balance safety, and further guide the layout of water level sensors and alarm design in the watertight compartment. Background Technology

[0002] The applicant's research revealed that watertight compartment design for seaplanes is a necessary measure to ensure safe operation on water. Airworthiness regulation CCAR-25-R4, Article 25.755, clearly stipulates the anti-sinking design requirements for watertight compartments. During seaplane operation, due to the influence of the natural environment, aerodynamic and hydrodynamic characteristics, and the sealing design of the watertight compartment structure, leakage and condensation are inevitable within the watertight compartment. Accumulation of this water can affect the aircraft's center of gravity, necessitating monitoring of water ingress and analysis of weight and balance to guide the determination of the seaplane's center of gravity envelope. Currently, there is no publicly available method for calculating the weight and balance of water ingress in seaplane watertight compartments. This makes it impossible to accurately assess the impact of leakage and condensation on the aircraft's center of gravity during operation, potentially leading to significant safety accidents and economic losses in the later stages of aircraft design and increasing the workload during later testing and flight trials. Summary of the Invention

[0003] The purpose of this invention is:

[0004] This invention aims to fundamentally solve the problem that the weight center envelope of a seaplane cannot be determined in the preliminary design stage, making it impossible to accurately determine the impact of water seepage and condensation on the aircraft's weight center of gravity during operation on the water surface. This can lead to significant safety accidents and economic losses in the later stages of aircraft design, and increase the workload in the later testing and flight test phases of the seaplane.

[0005] The technical solution of this invention is:

[0006] This invention provides a method for calculating the weight and balance of water ingress into the watertight compartment of a seaplane, supplementing the design method of the center of gravity envelope of the weight of amphibious aircraft, and increasing the safety and reliability of amphibious aircraft in waterborne test flights and operations.

[0007] The technical solution of this invention is: a method for calculating the weight and balance of a watertight compartment after water ingress, characterized by using a grid discretization method to calculate the weight state of the aircraft's watertight compartment after water ingress, and using numerical analysis methods to conduct weight and balance analysis of the aircraft after water ingress, ensuring that the calculated aircraft weight and center of gravity meet the selected safety margin value requirements for the center of gravity. This method includes the following steps:

[0008] S1. Determine the allowable value Δx for the safe center of gravity margin based on the aircraft's weight center of gravity envelope and relevant airworthiness regulations;

[0009] S2. Determine the relationship between the center of gravity of each watertight compartment and the center of gravity of the empty aircraft, and divide the center of gravity of the watertight compartment into two datasets: before the center of gravity of the empty aircraft and after the center of gravity of the empty aircraft.

[0010] S3. Determine the volume coefficient ratio of each watertight compartment relative to the reference watertight compartment based on the determined external volume of the watertight compartment;

[0011] S4. Using the volume coefficient ratio, select the No. 1 watertight compartment (1) as the calculation benchmark, and allow the water inflow to be assigned a value starting from 1. Combine the data obtained in the second article to carry out the analysis of the water inflow weight and balance of the aircraft's empty center of gravity before and after the center of gravity until the allowable value of the safe center of gravity margin Δx is met, and carry out an engineering feasibility assessment to determine feasibility.

[0012] S5. Select the water inlet volume of watertight chamber No. 1 (1) which is greater than and closest to the engineering realization value as the final water inlet volume value, and calculate the allowable water inlet volume of the remaining watertight chambers.

[0013] S6. Determine the final weight and balance analysis results of the watertight chambers, and ensure that the allowable water inflow of each watertight chamber meets the safety center of gravity margin allowance Δx requirement.

[0014] Preferably, step S1 includes:

[0015] Based on the final determined aircraft hull shape and watertight compartment distribution, a mathematical model for water ingress was established. The watertight compartments were numbered longitudinally along the aircraft from the coordinate reference point, designated as Watertight Compartment 1, Watertight Compartment 2, ..., Watertight Compartment i. The corresponding water ingress volume, center of gravity coordinates, volume, and volume coefficient were w, respectively. i x i v i k i ;

[0016] Relevant parameters are introduced, including the initially determined aircraft weight, the front and rear limits of the aircraft's center of gravity, the empty weight w, and the center of gravity x;

[0017] Based on the performance and handling stability assessment conclusions in the aircraft design demonstration, a safety margin value Δx is reserved for the center of gravity of the watertight compartment when determining the weight center envelope of the aircraft.

[0018] Preferably, step S2 includes:

[0019] Based on the final determined aircraft hull shape, the X-axis centroid coordinates of each watertight compartment in the overall aircraft coordinate system were measured, i.e., x... i ;

[0020] Determine x i The relationship between x and x, x i The m numbers ≤ x form dataset 1: (x1~x m x, 0, ..., 0)i The number of im items for x is assigned to another dataset 2: (0, ..., x m+1 ~x i ).

[0021] Preferably, step S3 includes:

[0022] Using formula v i =k i • v1 and the coefficient k of the corresponding watertight compartment determined according to the determined watertight compartment volume ratio. i value.

[0023] Preferably, step S4 includes:

[0024] Numerical analysis calculations are performed using the following formulas;

[0025]

[0026] In the formula: x'——is the center of gravity of the empty engine before or after water ingress;

[0027] w i —The weight of water entering the i-th watertight compartment;

[0028] x i —The centroid coordinates of the i-th watertight compartment are used as the approximate centroid value of the water inflow.

[0029] k i —The volume ratio of the i-th watertight compartment to the first watertight compartment;

[0030] v1 — Volume of the first watertight compartment;

[0031] v i —The volume of the i-th watertight compartment.

[0032] Preferably, step S5 includes:

[0033] Starting with 1, assign values ​​to w1. Using dataset 1 and formula (1), conduct an analysis of the aircraft's center of gravity x, forward water weight, and balance until x' ≥ Δx, and then conduct an engineering feasibility assessment. If feasible, select w1, which is greater than and closest to the engineering feasibility value, as the final value, and calculate w2 ~ w m ;

[0034] Ninth, assign values ​​to w1 starting from 1, and use dataset 2 and formula (1) to conduct a weight and balance analysis of water ingress behind the aircraft's center of gravity x, until x' ≥ Δx, and conduct an engineering feasibility assessment. If feasible, select w1 that is greater than and closest to the engineering feasibility value as the final value, and calculate w m+1 ~w i .

[0035] Preferably, step S6 includes:

[0036] If the feasibility assessment result in step S5 is not feasible, then Δx needs to be increased and the numerical analysis calculation should be repeated as in step S5.

[0037] The final weight and balance analysis results of the watertight compartments were determined, and the allowable water inflow for each watertight compartment was w1 to w2. i The center of gravity safety margin value Δx is met at the same time.

[0038] Preferably, the center of gravity of each watertight compartment is determined by the geometric center coordinates of the watertight compartment.

[0039] Preferably, in the dataset before and after the empty center of gravity, the number of samples is equal to the number of watertight compartments, and the number is padded with the value 0.

[0040] Preferably, the allowable values ​​of the safety margin Δx at the front boundary of the weight center of gravity envelope and the allowable values ​​of the safety margin Δx at the rear boundary of the weight center of gravity envelope can be different to obtain the optimal value for the weight center of gravity envelope design.

[0041] The advantages and beneficial effects of this invention are:

[0042] 1. When a seaplane is running on water, the effects of water seepage and condensation on the aircraft's weight and center of gravity can be accurately measured, preventing major safety accidents and economic losses in the later stages of aircraft design.

[0043] 2. The safety center of gravity margin selected in this invention is determined according to airworthiness regulations and relevant standards, which can better protect the safety of seaplanes.

[0044] 3. This invention fundamentally solves the problem of not being able to determine the weight center of gravity envelope of a seaplane during the preliminary design stage.

[0045] 4. This invention reduces the workload in the later stages of seaplane testing and flight trials, and improves the progress of aircraft development. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 Schematic diagram of mathematical model for water ingress into watertight compartment;

[0048] Figure 2 Schematic diagram of center of gravity safety margin.

[0049] Wherein: 1-No. 1 watertight compartment, 2-No. 2 watertight compartment, ..., i-No. 1 watertight compartment. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] The present invention will now be described in further detail.

[0053] The method for calculating the weight and balance of water-tight compartments in this invention uses a grid discretization method to calculate the weight state of the aircraft's watertight compartment after water ingress, and uses numerical analysis methods to conduct weight and balance analysis of the aircraft after water ingress, so that the calculated weight and center of gravity of the aircraft in attitude meet the selected safety center of gravity margin allowance requirements.

[0054] Figure 1 Schematic diagram of mathematical model for water ingress into watertight compartment; Figure 2 Schematic diagram of center of gravity safety margin.

[0055] refer to Figure 1 and Figure 2 This invention proposes a method for calculating the weight and balance of water ingress into the watertight compartments of seaplanes. This method is used to determine the allowable water ingress into each watertight compartment of the aircraft and further guides the layout and installation of water measurement devices. The implementation process is as follows:

[0056] First, based on the final determined aircraft hull shape and watertight compartment distribution, a mathematical model for water ingress is established. The watertight compartments are numbered longitudinally along the aircraft from the coordinate reference point, designated as Watertight Compartment 1, Watertight Compartment 2, ..., Watertight Compartment i. The corresponding water ingress volume, center of gravity coordinates, volume, and volume coefficient are w, respectively. i x i v i k i ;

[0057] Second, relevant parameters are introduced, including the initially determined aircraft weight, the front and rear limits of the aircraft's center of gravity, the empty weight w, and the center of gravity x.

[0058] Third, based on the aircraft's weight center of gravity envelope and relevant airworthiness regulations, determine the preliminary center of gravity safety margin value Δx;

[0059] Fourth, based on the final determined aircraft hull shape, the X-axis centroid coordinates of each watertight compartment in the overall aircraft coordinate system are measured, i.e., x... i ;

[0060] Fifth, determine x i The relationship between x and x, x i The m numbers ≤ x form dataset 1: (x1~x m x, 0, ..., 0) i The number of im items for x is assigned to another dataset 2: (0, ..., x m+1 ~x i );

[0061] Sixth, using formula v i =k i • v1 and the coefficient k of the corresponding watertight compartment determined according to the determined watertight compartment volume ratio. i value;

[0062] Seventh, perform numerical analysis calculations using the following formulas;

[0063]

[0064] Eighth, assign values ​​to w1 starting from 1, and use dataset 1 and formula (1) to conduct an analysis of the aircraft's center of gravity x, forward water weight, and balance until x' ≥ Δx, and conduct an engineering feasibility assessment. If feasible, select w1, which is greater than and closest to the engineering feasibility value, as the final value, and calculate w2 ~ w m ;

[0065] Ninth, assign values ​​to w1 starting from 1, and use dataset 2 and formula (1) to conduct a weight and balance analysis of water ingress behind the aircraft's center of gravity x, until x' ≥ Δx, and conduct an engineering feasibility assessment. If feasible, select w1 that is greater than and closest to the engineering feasibility value as the final value, and calculate w m+1 ~w i ;

[0066] Tenth, if the feasibility assessment results of the project in steps eight and nine are not feasible, then Δx needs to be increased, and the numerical analysis calculation should be repeated as in steps eight and nine.

[0067] Eleventh, determine the final weight and balance analysis results of the watertight chambers. The allowable water inflow for each watertight chamber is w1 to w1. i The center of gravity safety margin value Δx is met at the same time.

[0068] The beneficial effects of this invention are:

[0069] 1. When a seaplane is running on water, the effects of water seepage and condensation on the aircraft's weight and center of gravity can be accurately measured, preventing major safety accidents and economic losses in the later stages of aircraft design.

[0070] 2. The safety center of gravity margin selected in this invention is determined according to airworthiness regulations and relevant standards, which can better protect the safety of seaplanes.

[0071] 3. This invention fundamentally solves the problem of not being able to determine the weight center of gravity envelope of a seaplane during the preliminary design stage.

[0072] 4. This invention reduces the workload in the later stages of seaplane testing and flight trials, and improves the progress of aircraft development.

[0073] It should be noted that the above process operations can be combined to varying degrees. For the sake of brevity, the implementation methods of various combinations will not be elaborated here. Those skilled in the art can flexibly adjust the order of the above operation steps or flexibly combine the above steps according to actual needs.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for calculating the weight and balance of water ingress into the watertight compartment of a large seaplane, characterized in that, The method includes the following steps: S1. Determine the permissible safe center of gravity margin based on the aircraft's weight center of gravity envelope and relevant airworthiness regulations. ; S2. Determine the relationship between the center of gravity of each watertight compartment and the center of gravity of the empty aircraft, and divide the center of gravity of the watertight compartment into two datasets: before the center of gravity of the empty aircraft and after the center of gravity of the empty aircraft. S3. Determine the volume coefficient ratio of each watertight compartment relative to the reference watertight compartment based on the determined external volume of the watertight compartment; S4. Using the volume factor ratio, select watertight compartment No. 1 (1) as the calculation benchmark, and allow the water inflow to be assigned a value starting from 1. Combine the dataset obtained in the second article to carry out the analysis of the water inflow weight and balance of the aircraft's empty center of gravity until the allowable value of the safe center of gravity margin is met. And conduct a feasibility assessment of the project to determine its feasibility; S5. Select the water inlet volume of watertight chamber No. 1 (1) which is greater than and closest to the engineering realization value as the final water inlet volume value, and calculate the allowable water inlet volume of the remaining watertight chambers. S6. Determine the final weight and balance analysis results of the watertight compartments, ensuring that the allowable water inflow to each watertight compartment meets the allowable safety margin value for the center of gravity. Require; Step S1 includes: Based on the final determined aircraft hull shape and watertight compartment distribution, a mathematical model for water ingress was established. The watertight compartments were numbered longitudinally along the aircraft from a coordinate reference point, designated as Watertight Compartment 1, Watertight Compartment 2, ... The watertight chamber No. [number] has the following corresponding water inflow, center of gravity coordinates, volume, and volume coefficient: ; Relevant parameters are introduced, including the initially determined aircraft weight, the front and rear limits of the aircraft's center of gravity, and the empty weight. Center of gravity ; Based on the performance and handling stability assessment conclusions during the aircraft design demonstration, a safety margin for the center of gravity of the watertight compartments is reserved when determining the aircraft's weight center of gravity envelope. ; Step S2 includes: Based on the final determined aircraft hull shape, the X-axis centroid coordinates of each watertight compartment in the overall aircraft coordinate system were measured, i.e. ; judge and The size relationship will The m numbers form dataset 1: ( ,0,...,0), will > of The m numbers are grouped into another dataset 2: (0, ..., ... ).

2. The method as described in claim 1, characterized in that, Step S3 includes: Using formula And determine the coefficient of the corresponding watertight compartment based on the determined watertight compartment volume ratio. k i Values, where: ——No. The volume ratio of the first watertight compartment to the first watertight compartment; —The volume of the first watertight compartment; ——No. The volume of a watertight compartment.

3. The method as described in claim 2, characterized in that, Step S4 includes: Numerical analysis calculations are performed using the following formulas; （1） In the formula: —The center of gravity of the airframe before or after water ingress; ——No. The weight of water entering the watertight compartment; ——No. The centroid coordinates of the watertight compartment are used as approximate centroid values ​​for the water inflow. ——No. The volume ratio of the first watertight compartment to the first watertight compartment; —The volume of the first watertight compartment; ——No. The volume of a watertight compartment.

4. The method as described in claim 3, characterized in that, The S5 steps include: Will Starting from 1, the values ​​are assigned, and the center of gravity of the aircraft is determined using dataset 1 and formula (1). Forward water weight and balance analysis, until Stop, and conduct a feasibility assessment of the project. If feasible, select the value that is greater than and closest to the project's achievable value. As the final value, and calculated ; Will Starting with 1, values ​​are assigned, and the aircraft's center of gravity is determined using dataset 2 and formula (1). Post-inlet water weight and balance analysis, until Stop, and conduct a feasibility assessment of the project. If it is feasible, select the value that is greater than and closest to the project's achievable value. As the final value, and calculated .

5. The method as described in claim 4, characterized in that, Step S6 includes: If the feasibility assessment results in step S5 are not feasible, then the scale needs to be increased. Repeat the numerical analysis calculation as in step S5; The final weight and balance analysis results of the watertight compartments were determined, and the allowable water inflow rate for each watertight compartment was [determined]. When the center of gravity safety margin value is met Require.

6. The method as described in claim 1, characterized in that, in: The center of gravity of each watertight compartment is determined by the geometric coordinates of the centroid of the watertight compartment.

7. The method as described in claim 1, characterized in that, in: In both the dataset before and after the empty center of gravity, the number of samples is equal to the number of watertight compartments, and the number is padded with the value 0.

8. The method according to any one of claims 1-7, characterized in that, in: Allowable margin of safety center of gravity at the front boundary of the weight center of gravity envelope And the allowable value of safety margin for the center of gravity behind the weight center of gravity envelope Different values ​​can be selected to obtain the optimal value for the weight center of gravity envelope design.

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