A method for testing the fuel system of a tropospheric manned airship in flight with unusable fuel

Abstract

The present application belongs to the technical field of flight test, and particularly relates to a method for testing flight of a fuel system of a stratosphere manned airship under the condition of unavailable fuel. The method comprises the following steps: adding an auxiliary fuel supply system to the airship, so that the fuel system of the airship supplies fuel to one main engine, and the auxiliary fuel tank supplies fuel to other engines; and testing flight of the fuel system under the condition of unavailable fuel.

Description

Technical Field

[0001] This invention belongs to the field of flight test technology, specifically relating to a method for test flights of a tropospheric manned airship with unusable fuel. Background Technology

[0002] Currently, China lacks flight test technologies and methods for the qualification certification of tropospheric airships. There is a need to implement repeatable and standardized flight test requirements for airships, standardizing flight test preparation, procedures, and methods to form unified verification requirements and improve the efficiency and quality of manned airship flight tests. Summary of the Invention

[0003] Purpose of the invention: To provide a test flight method for a tropospheric manned airship with unavailable fuel, filling the gap in test flight methods for tropospheric manned airships with unavailable fuel, and improving the efficiency and quality of manned airship test flights.

[0004] Technical solution: A method for test flights of a tropospheric manned airship using unusable fuel systems includes: installing an auxiliary fuel supply system on the aircraft, enabling the onboard fuel system to supply fuel to one main engine and the auxiliary fuel tank to supply fuel to the other engines; and conducting test flights using unusable fuel systems.

[0005] Furthermore, the method specifically includes: S1: Install an auxiliary fuel supply system so that the onboard fuel system supplies fuel to one main engine and the auxiliary fuel tank supplies fuel to the other engines, and fills the main engine fuel tank with the minimum amount of fuel. S2: Fill up the fuel in other engines; S3: After the airship climbs to the minimum safe altitude, it switches to level flight; S4: After the scheduled time for level flight, the airship will circle and climb under the most unfavorable fuel supply conditions. During the climb, observe whether the engines supplied by the onboard fuel system are working properly. S5: If no engine malfunction is detected after climbing to the maximum operating altitude, return to base and land; S6: Calculate the total fuel consumption V0 from takeoff to landing based on the fuel flow data on board the ship; add 1 / 2V0 of fuel to the main engine fuel tank on the ground; S7: Repeat steps S2-S6 until the unusable fuel is exhausted, and the airship lands according to the single-engine landing procedure. S8: Determine the remaining fuel volume to obtain the unusable fuel volume.

[0006] Furthermore, the minimum fuel quantity in S2 is determined based on theoretical calculations.

[0007] Furthermore, the time interval between reservations in S4 is 3-5 minutes.

[0008] Furthermore, the elevation increment in S4 is no less than 610m.

[0009] Furthermore, when the engine in S4 begins to malfunction, the symptoms include unstable fuel supply pressure and flow rate and / or a rapid drop in engine speed.

[0010] Furthermore, in S4, if the engine supplied by the ship's fuel system malfunctions, the engine and its corresponding fuel cut-off valve will be immediately shut down, and the ship will return to port for landing.

[0011] Furthermore, the amount of unusable fuel is discharged, specifically: The engine experienced a fuel supply malfunction during the climb. The elevation increment shall not be less than 610m.

[0012] Furthermore, S8, specifically: Drain the fuel from the main engine fuel tank into a tare-weighed fuel container, weigh it and record the weight, and calculate the volume of remaining fuel to obtain the amount of unusable fuel.

[0013] Furthermore, it also includes: if no unusable fuel is flown out, returning to step S1 and modifying the initial conditions of S1 and S2.

[0014] Beneficial effects: This invention fills a gap in the qualification test flight method for unusable fuel types in the fuel system of tropospheric manned airships, realizes a repeatable and standardized test flight plan, standardizes test flight preparation, test flight procedures and test flight methods, forms unified verification requirements, and improves the test flight efficiency and test flight quality of unusable fuel in the fuel system of tropospheric manned airships. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. 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.

[0016] Figure 1 This is a flowchart of a method for test flights of a tropospheric manned airship where the fuel system is unavailable. Detailed Implementation

[0017] 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.

[0018] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0019] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0021] 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.

[0022] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0023] The Civil Aviation Administration of China (CAAC) issued the type certification for the airship (AC-21-AA-2009-09R1), which adopted FAA P-8110-2 airship design guidelines, specifically Clause 5.13 regarding unusable fuel in the fuel system. It explicitly requires that the amount of unusable fuel in each fuel tank must be no less than the following: the amount of fuel in the tank at the moment when engine malfunction begins under the most unfavorable fuel supply conditions for all scheduled operations and maneuvers requiring fuel from that tank. Based on this requirement, this invention clarifies the flight test method for unusable fuel in the airship's fuel system and provides qualification criteria.

[0024] This invention provides a method for test flights of unavailable fuel for the tropospheric manned fuel system applicable to FAA P-8110-2, the method comprising the following steps: Step 1: Preparing conditions for test flight; 1) Weight and center of gravity: No requirement; 2) Airship equipped with: Auxiliary fuel supply system; 3) Fuel quantity: Based on theoretical calculations, the main fuel tank is filled with the minimum amount of fuel (calculated using CATIA graphical methods, simulations, and other theoretical methods). The main engine fuel tank is filled with the minimum amount of fuel. The auxiliary fuel supply system fills the other engines with fuel. The onboard fuel system supplies fuel to one main engine, and the auxiliary fuel tank supplies fuel to the other engines. Step 2: Take off according to the standard flight procedure. After the airship climbs to the minimum safe altitude, it will switch to level flight. Step 3: After flying level for 3-5 minutes, the airship will circle and climb under the most unfavorable fuel supply conditions (climb increment not less than 610m). During the climb, observe whether the engine supplied by the onboard fuel system is working properly (the signs of engine malfunction include unstable fuel pressure and fuel flow, rapid drop in engine speed, etc.). Step 4: If the engine supplied by the ship's fuel system malfunctions, immediately shut down the engine and the corresponding fuel cut-off valve, and return to port for landing. If no abnormal situation occurs, climb to the maximum operating altitude and return to land; Step 5: Calculate the total fuel consumption V0 from takeoff to landing based on the fuel flow data on board the submarine; add 1 / 2V0 of fuel to the main fuel tank on the ground; Step 6: Fill the other engines with fuel using the auxiliary fuel supply system, and repeat steps 2 to 5 until the fuel supply becomes unusable (if a fuel supply malfunction occurs during the climb). The airship then lands according to the single-engine landing procedure. Step 7: Drain the fuel from the tank into a tare-weighed fuel container, weigh it and record the weight, and calculate the volume of the remaining fuel.

[0025] Step 8: Qualification Criteria; 1) The engine experienced abnormal fuel supply during the climb; 2) The elevation increment shall not be less than 610m.

[0026] Step 9: Complete the test flight with unusable fuel in the fuel system.

[0027] Example: The process for implementing unavailable fuel systems in tropospheric manned airships is as follows: Figure 1 As shown: The following is the test flight process for the qualification certification of an unusable fuel type in the fuel system of a certain manned airship: 1) Set up the test conditions according to the test requirements before the test; Test conditions setting: Select the normal weight and normal center of gravity of the airship as the test benchmark. Before the test, add 50L of aviation gasoline to the onboard fuel tank (estimate the amount of fuel based on climbing to 1000 meters, which can be adjusted according to the flight conditions) and add aviation gasoline to the auxiliary fuel supply system fuel tank until the fuel gauge indicates full (about 80L); The operator uses a platform scale to weigh the measuring cylinder after tareing, and measures the fuel without exceeding the range through the fuel drain valve of the sedimentation tank, calculates the fuel density, repeats 3 times and records the results; 2) The airship takes off normally and climbs to the minimum safe altitude of 50m~100m and maintains level flight; 3) Climb to the left under the most unfavorable fuel supply conditions, i.e., at the maximum pitch angle of 30°±3° (Note: the climb increment shall not be less than 610m; in the left turn climb state, the left engine shall be fueled by the auxiliary fuel supply system and the right engine shall be fueled by the onboard fuel system). 4) When an engine supplied by the ship's fuel system malfunctions (symptoms of malfunction include unstable fuel pressure and flow rate, and a rapid drop in engine speed; abnormal engine sounds and vibrations cannot be used as acceptable criteria by the pilot), immediately shut down the engine and the corresponding fuel cut-off valve, and return to port for landing. 5) If no engine malfunction occurs after climbing to the maximum operating altitude, return to base and land; 6) Calculate the total fuel consumption V0 from takeoff to landing based on the fuel flow data on board the submarine; 7) Add 1 / 2V0 of fuel to the main fuel tank on the ground to allow the auxiliary fuel supply system to fill the other engines with fuel; 8) Repeat steps 2) to 5) until the unusable fuel level is reached; 9) The test ends, and the airship lands according to the single-engine landing procedure; 10) The operator drains the fuel from the tank into a tare-weighed fuel container, weighs it on a platform scale and records the weight, and calculates the remaining fuel volume.

[0028] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for test flights of a tropospheric manned airship where the fuel system cannot be fueled, characterized in that, include: An auxiliary fuel supply system is installed on the aircraft so that the onboard fuel system supplies fuel to one main engine and the auxiliary fuel tank supplies fuel to the other engines. Conduct test flights with unusable fuel in the fuel system.

2. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... include: S1: Install an auxiliary fuel supply system so that the onboard fuel system supplies fuel to one main engine and the auxiliary fuel tank supplies fuel to the other engines, and fills the main engine fuel tank with the minimum amount of fuel. S2: Fill up the fuel in other engines; S3: After the airship climbs to the minimum safe altitude, it switches to level flight; S4: After the scheduled time for level flight, the airship will circle and climb under the most unfavorable fuel supply conditions. During the climb, observe whether the engines supplied by the onboard fuel system are working properly. S5: If no engine malfunction is detected after climbing to the maximum operating altitude, return to base and land; S6: Calculate the total fuel consumption V0 from takeoff to landing based on the fuel flow data on board the ship; add 1 / 2V0 of fuel to the main engine fuel tank on the ground; S7: Repeat steps S2-S6 until the unusable fuel is exhausted, and the airship lands according to the single-engine landing procedure. S8: Determine the remaining fuel volume to obtain the unusable fuel volume.

3. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... The minimum fuel quantity in S2 is determined based on theoretical calculations.

4. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... The reservation time in S4 is 3-5 minutes.

5. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... The elevation increment in S4 is no less than 610m.

6. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... When the engine in S4 starts to malfunction, the signs include unstable fuel supply pressure and flow rate and / or a rapid drop in engine speed.

7. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... In S4, if the engine supplied by the ship's fuel system malfunctions, the engine and its corresponding fuel cut-off valve should be shut down immediately, and the ship should return to port and land.

8. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... The amount of unusable fuel discharged is as follows: The engine experienced a fuel supply malfunction during the climb. The elevation increment shall not be less than 610m.

9. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... S8, specifically: Drain the fuel from the main engine fuel tank into a tare-weighed fuel container, weigh it and record the weight, and calculate the volume of remaining fuel to obtain the amount of unusable fuel.

10. The method for test flights of a tropospheric manned airship without fuel, as described in claim 1, is characterized in that... Also includes: If no unusable fuel is flown out, return to step S1 and modify the initial conditions of S1 and S2.

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