A troposphere manned airship airspeed indication and static pressure system calibration flight test method

Abstract

This invention belongs to the field of flight test technology and discloses a test flight method for calibrating the airspeed indication and static pressure system of a tropospheric manned airship. The steps are as follows: S1, select the test flight speed and altitude; S2, after the airship climbs to the test flight altitude, it maintains stable level flight at the test flight speed; S3, select the heading, and after trimming with a speed deviation of less than 1.8 km / h and an altitude deviation of less than 20 m, it maintains stable flight along the first side for time T; after adjusting the heading angle α, it maintains stable flight along the second side for time T; after adjusting the heading angle β, it maintains stable flight along the third side for time T; parameters are collected during the flight; S4, calculate the vacuum speed and correct the airspeed; S5, select other test flight speeds and altitudes, and repeat S2~S4 to continue the test flight.

Description

Technical Field

[0001] This invention belongs to the field of flight test technology and discloses a calibration test flight method for the airspeed indication and static pressure system of a tropospheric manned airship. 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 weight, center of gravity, procedures, and methods to form unified verification requirements and improve the efficiency and quality of manned airship flight tests.

[0003] The Civil Aviation Administration of China (CAAC) issued the type certification for the airship (AC-21-AA-2009-09R1), which adopted Articles 6.9(b) and 6.11(e) of the (FAA P-8110-2) airship design guidelines, which stipulate the calibration of airspeed indication and static pressure systems. It clearly requires that each airspeed system must be calibrated in flight to determine the system error. The system error (including position error, but excluding airspeed indication instrument calibration error) shall not exceed 9.3 km / h (5 kt) from 37 km / h (20 kt) to VMO speed. The design and installation of each system must ensure that the indicated pressure altitude error (excluding instrument calibration error) under standard atmospheric conditions at sea level does not result in an error exceeding 9 m (30 ft) within the 37 km / h (20 kt) and VMO speed range. Although the Civil Aviation Administration of China's document AC-21-AA-2009-09R1 clarifies the calibration requirements for the airship's airspeed system and static pressure system based on the FAA P-8110-2 standard, it does not disclose the specific test flight methods and operational details. Summary of the Invention

[0004] This invention provides a method for calibrating the airspeed indication and hydrostatic system of a tropospheric manned airship. It fills a gap in flight test methods for calibrating the airspeed indication and hydrostatic system of a tropospheric manned airship, improving the efficiency and quality of manned airship flight tests.

[0005] Technical solution: A calibration test method for the airspeed indication and static pressure system of a tropospheric manned airship, comprising the following steps: S1. Select the test flight speed and test flight altitude; S2. After the airship climbs to the test flight altitude, it will maintain stable level flight at the test flight speed. S3. Select a heading, and after trimming with a speed deviation of less than 1.8 km / h and an altitude deviation of less than 20 m, stabilize the flight along the first side for time T; adjust the heading angle α and stabilize the flight along the second side for time T; then adjust the heading angle β and stabilize the flight along the third side for time T; collect parameters during the flight. S4. Calculate vacuum velocity and correct space velocity; S5. Select other test flight speeds and altitudes, and repeat S2~S4 to continue the test flight.

[0006] Furthermore, in S1, the test flight speeds include: 37 km / h, and the maximum operating speed limit V. MO and 37km / h~V MO The speed should be no less than 1.

[0007] Furthermore, in S1, the test flight altitude includes 1 to 3 altitudes between the minimum safe flight altitude and the maximum usable altitude, with a difference of not less than 500m between any two altitudes.

[0008] Furthermore, in S3, T ≥ 20s.

[0009] Furthermore, in S3, the values ​​of α and β are both within the range of 100°±10°, and their directions are either clockwise or counterclockwise.

[0010] Furthermore, in S3, the parameters collected include: indicated airspeed, GPS ground speed, heading angle, pressure altitude, and atmospheric temperature.

[0011] Furthermore, in S4, the process of calculating the vacuum velocity and correcting the space velocity is as follows: S41. Suppose that the ground speed and trajectory angle of the three sides of the flight are as follows, under the same flight altitude and speed: , , , , , , S42. Calculate the eastward and northward velocity components of the ground velocity of the three sides of the flight path, respectively.

[0012] The value of i is 1, 2, or 3; S43. Calculate the eastward and northward components of wind speed:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] Calculate wind speed: ; Calculate wind direction The unit is angle, clockwise from due north; mod represents the remainder; S44. Calculate vacuum velocity ; S45. Calculate the corrected airspeed ; Test height air density ρ H Calculations are performed by substituting atmospheric temperature, pressure, and altitude into the air state equation:

[0019] P H It is the measured atmospheric pressure, T H It is the measured static temperature; ρ0 is the standard atmospheric density at sea level. S46. Calculate the air pressure altitude of the static pressure system. dh

[0020] P HI V is the atmospheric density ratio. CAS To correct for airspeed, dV CAS For V CAS The difference between the indicated airspeed and the corrected airspeed.

[0021] Furthermore, the method also includes: determining whether the test flight is qualified, with the following qualification criteria: 1) Speed ​​deviation not greater than 1.8 km / h, height error not greater than 20 m; 2) The indicated airspeed is within the range of 37 km / h to VMO speed, and the airspeed error does not exceed 9.3 km / h; 3) The pressure altitude error shall not exceed ±9m within the indicated airspeed range of 37km / h to VMO speed.

[0022] Beneficial effects: This invention fills the gap in the test flight method for the calibration of airspeed indication and static pressure system of tropospheric manned airships, realizes a repeatable and standardized test flight plan, and standardizes the test flight weight, center of gravity, test flight procedures and test flight methods to form unified verification requirements, thereby improving the test flight efficiency and test flight quality of tropospheric manned airship airspeed indication and static pressure system calibration. Attached Figure Description

[0023] 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.

[0024] Figure 1 This is a flowchart of the flight test process of the present invention. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] A calibration flight test method for the airspeed indication and static pressure system of a tropospheric manned airship, meeting the requirements of FAA P-8110-2 specification, such as... Figure 1 As shown, it includes the following steps: Step 1: Preparing conditions for test flight; Weight and center of gravity: Normal weight, normal center of gravity; Airship upgrade: Install differential GPS; Speed: 37km / h~V MO (Maximum operating speed limit), speed selection includes 37km / h, V MO (Maximum operating speed limit), other speeds are between 37 km / h and V. MO You must select at least one of the following (maximum usage speed limits); Altitude: Minimum safe flight altitude to maximum operating altitude, 1 to 3 altitudes, with the altitude difference between any two altitudes not less than 500m; Step 2: After the airship climbs to the selected altitude, it will fly steadily at a level speed. Adjust the speed to the selected speed and fly steadily at a level speed. Step 3: Select a course, and after trimming with a speed deviation of less than 1.8 km / h and an altitude deviation of less than 20 m, complete the first side of stable flight for no less than 20 seconds; Step 4: Adjust the heading angle clockwise or counterclockwise, making it 100° ± 10° different from the heading angle of the first side. After trimming at the same altitude and speed, maintain stable flight on the second heading side for no less than 20 seconds.

[0032] Step 5: Adjust the heading angle in the same direction as in Step 4, with a difference of 100°±10° from the heading angle of the second side. After trimming at the same altitude and speed, maintain stable flight on the third side for no less than 20 seconds. Step 6: Adjust the speed and repeat steps 2 through 5.

[0033] Step 7: Adjust the height and repeat steps 1 through 6.

[0034] Step 8: Data Processing Key data collected: indicated airspeed, GPS ground speed, heading angle, pressure altitude, and atmospheric temperature (OAT).

[0035] Vacuum airspeed and corrected airspeed calculation: For stable three-way flight, the indicated airspeed and ambient air temperature (OAT) and pressure altitude are the same (flying at the set indicated airspeed). Due to wind influence, the ground speeds at the three sides may differ. Ground speeds are measured by GPS. Since wind speed is constant, the influence of wind can be eliminated using a geometric method based on the direction of the three ground tracks and the magnitude of the ground speeds, thus calculating the vacuum airspeed for stable three-way level flight. Then, atmospheric density conversion is used to convert the vacuum airspeed to a corrected airspeed (used for comparison with the set indicated airspeed). The specific data processing method is as follows: Basic parameters: Let the ground speed and track angle of the three test flights be as follows: Ground speed during triangular flight: , , (Unit: kilometers per hour) Heading angles for tri-plane flight: , , The corresponding track angle (unit: degrees, measured clockwise from due north).

[0036] Velocity component calculation The ground velocity components are divided into eastward (X) and northward (Y) components, for i=1,2,3

[0037] Linear parameter calculation Line 1 passes through points (X1, Y1) and (X2, Y2):

[0038]

[0039] Line 2 passes through points (X1, Y1) and (X3, Y3):

[0040]

[0041] Wind speed component calculation

[0042] Wind speed and direction calculation Wind speed:

[0043] Wind direction (in degrees, clockwise from due north):

[0044] Vacuum speed (TAS) calculation Select the first set of data points (X1, Y1)

[0045] Corrected airspeed (CAS) calculation

[0046] Test height air density ρ H Calculations are performed by substituting atmospheric temperature, pressure, and altitude into the air state equation:

[0047] P H It is the measured atmospheric pressure (unit: Pa), T H This is the measured static atmospheric temperature (unit: K). Static pressure system air pressure altitude:

[0048] In the formula, P HI V is the atmospheric density ratio. C To correct airspeed (V) CAS (The range is 37km~V) MO ), dV C For V C The corresponding indicated airspeed and corrected airspeed (V CAS The difference between ).

[0049] Step 9: Criteria for Qualification; 1) The speed deviation of valid test flight data shall not exceed 1.8 km / h, and the altitude error shall not exceed 20 m.

[0050] 2) The indicated airspeed is within the range of 37 km / h to VMO speed, and the airspeed error does not exceed 9.3 km / h; 3) The pressure altitude error shall not exceed ±9m within the indicated airspeed range of 37km / h to VMO speed.

[0051] Step 10: Complete the test flight to calibrate the airspeed indication and static pressure systems.

[0052] Example: The calibration and certification test flight process for the airspeed indication and static pressure system of a manned airship is as follows: 1) Before the test, set the parameters according to the test requirements: the airship is equipped with differential GPS, normal weight and normal center of gravity; the initial selected speeds are 37km / h, 50km / h, 70km / h, 80km / h, and the maximum continuous power speed; the selected field heights are 500m, 1000m, and 1500m.

[0053] 2) After the airship climbs to an altitude of 500m, adjust the speed to 37km / h, maintain an altitude of 500m, maintain a heading of 100°±10° for trim, and complete the first side stable level flight for no less than 20s; 3) Adjust the heading angle clockwise to 200°±10°, and after trimming at the same altitude (500m) and speed (37km / h), maintain stable flight on the second heading side for no less than 20 seconds; 4) Adjust the heading angle clockwise to 300°±10°, and after trimming at the same altitude (500m) and speed (37km / h), maintain stable flight on the third side of the heading for no less than 20 seconds; 5) Adjust the speed to 50km / h, 70km / h, 80km / h, and the maximum continuous power speed, and repeat steps 2) to 4). 6) Adjust the altitude to 1000m or 1500m, and repeat steps 1) to 5). 7) Normal return and landing; 8) Data processing: Process the data according to the indicated airspeed and static pressure system pressure altitude data processing methods.

[0054] 9) Criteria for success of the experiment: i) The speed deviation of valid test flight data shall not exceed 1.8 km / h, and the altitude error shall not exceed 20 m.

[0055] ii) The airspeed error shall not exceed 9.3 km / h within the indicated airspeed range of 37 km / h to VMO speed; iii) The pressure altitude error shall not exceed ±9m within the indicated airspeed range of 37km / h to VMO speed.

[0056] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for calibrating and testing the airspeed indication and static pressure system of a tropospheric manned airship, characterized in that: S1. Select the test flight speed and test flight altitude; S2. After the airship climbs to the test flight altitude, it will maintain stable level flight at the test flight speed. S3. Select a heading, and after trimming with a speed deviation of less than 1.8 km / h and an altitude deviation of less than 20 m, stabilize the flight along the first side for time T; adjust the heading angle α and stabilize the flight along the second side for time T; then adjust the heading angle β and stabilize the flight along the third side for time T; collect parameters during the flight. S4. Calculate vacuum velocity and correct space velocity; S5. Select other test flight speeds and altitudes, and repeat S2~S4 to continue the test flight.

2. The method according to claim 1, characterized in that: In S1, test flight speeds include: 37 km / h, and the maximum operating speed limit V. MO and 37km / h~V MO The speed should be no less than 1.

3. The method according to claim 2, characterized in that: In S1, the test flight altitude includes 1 to 3 altitudes between the minimum safe flight altitude and the maximum usable altitude, with a difference of no less than 500m between any two altitudes.

4. The method according to claim 3, characterized in that: In S3, T ≥ 20s.

5. The method according to claim 4, characterized in that: In S3, the values ​​of α and β are both within the range of 100°±10°, and their directions are either clockwise or counterclockwise.

6. The method according to claim 5, characterized in that: In S3, the parameters collected include: indicated airspeed, GPS ground speed, heading angle, pressure altitude, and atmospheric temperature.

7. The method according to claim 6, characterized in that: In S4, the process of calculating vacuum velocity and correcting space velocity is as follows: S41. Suppose that the ground speed and trajectory angle of the three sides of the flight are as follows, under the same flight altitude and speed: , , , , , , S42. Calculate the eastward and northward velocity components of the ground velocity of the three sides of the flight path, respectively. The value of i is 1, 2, or 3; S43. Calculate the eastward and northward components of wind speed: Calculate wind speed: ; Calculate wind direction The unit is angle, clockwise from due north; mod represents the remainder; S44. Calculate vacuum velocity ; S45. Calculate the corrected airspeed ; Test height air density ρ H Calculations were performed by substituting atmospheric temperature, pressure, and altitude into the air state equation: P H It is the measured atmospheric pressure, T H It is the measured static temperature; ρ0 is the standard atmospheric density at sea level. S46. Calculate the air pressure altitude of the static pressure system. dh P HI V is the atmospheric density ratio. CAS To correct for airspeed, dV CAS For V CAS The difference between the indicated airspeed and the corrected airspeed.

8. The method according to claim 7, characterized in that: The method further includes: determining whether the test flight is qualified, with the following qualification criteria: 1) Speed ​​deviation not greater than 1.8 km / h, height error not greater than 20 m; 2) The indicated airspeed is within the range of 37 km / h to VMO speed, and the airspeed error does not exceed 9.3 km / h; 3) The pressure altitude error shall not exceed ±9m within the indicated airspeed range of 37km / h to VMO speed.

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