CN109703778B - Undercarriage buffer rigidization method for aircraft load calibration test - Google Patents
Undercarriage buffer rigidization method for aircraft load calibration test Download PDFInfo
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- CN109703778B CN109703778B CN201811264151.2A CN201811264151A CN109703778B CN 109703778 B CN109703778 B CN 109703778B CN 201811264151 A CN201811264151 A CN 201811264151A CN 109703778 B CN109703778 B CN 109703778B
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Abstract
The invention discloses a stiffening method of an undercarriage buffer for an aircraft load calibration test, belongs to the technical field of flight tests, and relates to the aircraft load calibration test, wherein the stiffening of the undercarriage buffer is realized by a method for charging high-pressure nitrogen into an air cavity of the undercarriage buffer, the support and constraint of an aircraft in the aircraft body load calibration test process are solved, and the solving steps are as follows: calculating the maximum axial force borne in the undercarriage buffer calibration test; determining the pressure of filling high-purity nitrogen into the air cavity of the buffer; jacking the airplane; filling high-purity nitrogen into the air cavity of the undercarriage buffer; and (5) dropping the airplane, and completing the stiffening of the undercarriage buffer of the load calibration test. The method ensures that the false landing gear for fixing the buffer stroke of the landing gear is not required to be replaced in the aircraft calibration test, and the rigidity of the landing gear buffer is realized by wrapping the buffer fixed stroke without designing and developing a buffer sleeve.
Description
Technical Field
The invention discloses a stiffening method of an undercarriage buffer for an aircraft load calibration test, belongs to the field of aircraft flight tests, and relates to a method for supporting and restraining an aircraft undercarriage during the aircraft load calibration test.
Background
The actual measurement of the airplane load is a necessary project for designing, shaping and trial flight of a new airplane. At present, the strain method is commonly adopted in China, abroad and abroad to actually measure the flying load of the airplane. The method is a precondition and a key of the actual measurement of the load, and is an important link related to whether the actual measurement result of the load is correct or not. The load calibration test is to simulate the loading condition of the part to be tested of the airplane in actual flight, to apply known load to the structural part additionally provided with the strain bridge, a quantitative relation between the load and the bridge output, namely a load equation is established, and when the known load is applied, the constraint of the airplane is fixedly related to the attitude of the airplane, and further the safety of the airplane is related.
When the airplane is subjected to a load calibration test, in order to ensure the safety of the airplane, corresponding constraint measures are required to be adopted to fix the airplane, the attitude of the airplane is not changed as much as possible in the whole test process, and the airplane displacement is suddenly changed in the loading implementation process.
Disclosure of Invention
The purpose of the invention is as follows: the method is simple to operate, uses the inherent equipment of the airplane, does not need to newly develop other non-standard equipment, realizes the functions of fixing the stroke of the landing gear buffer strut in the calibration test process, avoiding the phenomenon of sudden lifting and sudden falling, limits the rigid displacement of the airplane body in the loading process and improves the safety of the airplane in the test process.
The technical scheme of the invention is as follows:
a method of stiffening a landing gear bumper for an aircraft load calibration test, the method comprising the steps of:
step 1: calculating the load bearing load of each undercarriage in the aircraft load calibration test process of the aircraft, statistically calculating the maximum load borne by each undercarriage in the whole calibration test process according to the calibration working condition designed in the aircraft load calibration test scheme, and calculating the maximum axial force borne by each undercarriage buffer in the calibration test according to the weight of the aircraft, the position of the center of gravity and the relative position of the center of gravity of the aircraft and each undercarriage wheel;
step 2: determining the pressure of filling high-purity nitrogen into the air cavity of the buffer, and dividing the maximum axial force of each undercarriage buffer obtained in the step 1 by the cross sectional area of the piston of each undercarriage buffer respectively to obtain the pressure of filling high-purity nitrogen required by each undercarriage buffer air cavity;
and step 3: jacking the airplane by using a jack to ensure that a piston rod of a buffer of the airplane is completely extended out;
and 4, step 4: opening an inflating nozzle of an undercarriage buffer of the airplane, inflating high-purity nitrogen into the undercarriage buffer air cavity through the inflating nozzle by using inflating equipment, so that the pressure in each frame buffer air cavity is respectively greater than or equal to the pressure corresponding to each undercarriage buffer air cavity obtained by calculation in the step 2 and smaller than the pressure corresponding to the maximum designed axial force of each undercarriage buffer, and closing the undercarriage inflating nozzle filled with high-pressure gas;
and 5: and (5) dropping the airplane, and completing the stiffening of the undercarriage buffer of the load calibration test.
And 3, jacking the airplane by using an original airplane jack matched with the airplane.
In step 3, in the process of jacking up the aircraft, the piston rod of the buffer is completely extended by means of the self gravity of the piston rod, the gravity of the aircraft wheel and the inherent gas pressure in the buffer air cavity of the landing gear.
In step 4, the gas charging equipment is a high-purity nitrogen gas tank or a high-purity nitrogen gas charging vehicle.
The invention has the advantages that: the undercarriage buffer rigidization method for the aircraft load calibration test is used for restraining and fixing the aircraft during the calibration test, and has the following advantages and positive effects:
a) in a load calibration test, a false undercarriage for fixing the undercarriage buffer does not need to be replaced, so that the cost of the calibration test is reduced;
b) the buffer sleeve is not required to be designed and developed to wrap the buffer so as to fix the buffer stroke, and the risks of abrasion and damage to the original buffer are reduced;
c) the landing gear buffer does not need to be deflated and then refilled with oil in a fixed stroke, so that the risk of oil source pollution is reduced;
d) the gas used by the invention is the common gas filled in the air cavity of the aircraft landing gear buffer, and has stable chemical property, low cost and easy acquisition;
e) the method provided by the invention is simple to operate and easy to implement, the stiffening of the buffer can be conveniently finished by using the original machine equipment, and the landing gear is conveniently restored to the original state after the calibration test.
Drawings
FIG. 1 buffer schematic
In the figure: 1-buffer air cavity 2-buffer oil cavity 3-piston 4-charging connector
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
A method of stiffening a landing gear bumper for an aircraft load calibration test, the method comprising the steps of:
step 1: calculating the load bearing of each landing gear of the strain modified aircraft in the aircraft load calibration test process which needs to be carried out with calibration tests and has finished, calculating the maximum load bearing of each landing gear in the whole calibration test process according to the calibration working condition designed in the aircraft load calibration test scheme, calculating the maximum axial force borne by each landing gear buffer calibration test based on the relationship between the weight of the aircraft, the position of the center of gravity and the relative position of the center of gravity of the aircraft and wheels of each landing gear, and taking the maximum axial force borne by each landing gear buffer calibration test which is calculated in the step as the input of the step 2, wherein whether the stroke of the buffer is compressed or not in the whole calibration test process in the later period is determined according to the relationship between the maximum axial force borne by each landing gear buffer calibration test which is calculated in the step, and calculating all the calibration working conditions certainly;
step 2: determining the pressure of filling high-purity nitrogen into the buffer air cavity, and dividing the maximum axial force of each undercarriage buffer obtained in the step 1 by the cross-sectional area of each undercarriage buffer piston to obtain the pressure of filling high-purity nitrogen required by each undercarriage buffer air cavity, wherein the cross-sectional area of each undercarriage buffer piston can be obtained from an undercarriage design manual;
and step 3: the jack is used for jacking the airplane, the original jack matched with the airplane is proposed to jack the airplane, the jacking safety can be ensured, the jack stroke can meet the requirement that a buffer piston rod completely extends out in the jacking process of the airplane, the buffer piston rod can completely extend out by relying on the dead weight of the piston rod, the gravity of the airplane wheel and the inherent gas pressure in an air cavity of a buffer of an undercarriage in the jacking process of the airplane, and other auxiliary equipment is not needed, namely the piston 3 reaches the lowest limiting position in the attached drawing;
and 4, step 4: opening an inflating nozzle 4 of an undercarriage buffer of the airplane, and inflating high-purity nitrogen into an undercarriage buffer air cavity 1 through the inflating nozzle 4 by using a high-purity nitrogen tank or a high-purity nitrogen inflation vehicle, so that the pressure in each undercarriage buffer air cavity is respectively greater than or equal to the pressure corresponding to each undercarriage buffer air cavity calculated in the step 2 and smaller than the pressure corresponding to the maximum design axial force of each undercarriage buffer, and closing the undercarriage inflating nozzle 4 filled with high-pressure gas;
and 5: and (5) dropping the airplane, and completing the stiffening of the undercarriage buffer of the load calibration test.
Claims (4)
1. A method of stiffening a landing gear bumper for use in an aircraft load calibration test, the method comprising the steps of:
step 1: calculating the load bearing load of each undercarriage in the aircraft load calibration test process of the aircraft, statistically calculating the maximum load borne by each undercarriage in the whole calibration test process according to the calibration working condition designed in the aircraft load calibration test scheme, and calculating the maximum axial force borne by each undercarriage buffer in the calibration test through the aircraft weight, the aircraft gravity center and the relative position of each undercarriage wheel;
step 2: determining the pressure of filling high-purity nitrogen into the air cavity of the buffer, and dividing the maximum axial force of each undercarriage buffer obtained in the step 1 by the cross sectional area of the piston of each undercarriage buffer respectively to obtain the pressure of filling high-purity nitrogen required by each undercarriage buffer air cavity;
and step 3: jacking the airplane by using a jack to ensure that a piston rod of a buffer of the airplane is completely extended out;
and 4, step 4: opening an inflating nozzle of an undercarriage buffer of the airplane, inflating high-purity nitrogen into the undercarriage buffer air cavity through the inflating nozzle by using inflating equipment, so that the pressure in each frame buffer air cavity is respectively greater than or equal to the pressure corresponding to each undercarriage buffer air cavity obtained by calculation in the step 2 and smaller than the pressure corresponding to the maximum designed axial force of each undercarriage buffer, and closing the undercarriage inflating nozzle filled with high-pressure gas;
and 5: and (5) dropping the airplane, and completing the stiffening of the undercarriage buffer of the load calibration test.
2. A method of stiffening a landing gear bumper for use in aircraft load calibration tests according to claim 1, wherein in step 3 the aircraft is dropped using original jacks associated with the aircraft.
3. A method of stiffening a landing gear bumper for use in aircraft load calibration tests according to claim 1 wherein in step 3, the bumper piston rod is fully extended by virtue of the piston rod's own weight, the wheel weight, the inherent gas pressure in the landing gear bumper air cavity during the aircraft jacking.
4. A landing gear bumper stiffening method for aircraft load calibration tests according to claim 1, wherein in step 4, the inflation equipment is a high purity nitrogen gas tank or a high purity nitrogen gas inflation vehicle.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811264151.2A CN109703778B (en) | 2018-10-26 | 2018-10-26 | Undercarriage buffer rigidization method for aircraft load calibration test |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811264151.2A CN109703778B (en) | 2018-10-26 | 2018-10-26 | Undercarriage buffer rigidization method for aircraft load calibration test |
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| Publication Number | Publication Date |
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| CN109703778A CN109703778A (en) | 2019-05-03 |
| CN109703778B true CN109703778B (en) | 2022-05-27 |
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| CN201811264151.2A Active CN109703778B (en) | 2018-10-26 | 2018-10-26 | Undercarriage buffer rigidization method for aircraft load calibration test |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110683075B (en) * | 2019-10-29 | 2020-12-01 | 燕山大学 | Calibration device for rotary loader of nose landing gear |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6317956B1 (en) * | 1999-06-11 | 2001-11-20 | George R. Blankenship | Method and apparatus for removing an aircraft strut from an aircraft having retractable landing gear |
| CN104573347A (en) * | 2014-12-26 | 2015-04-29 | 北京空间机电研究所 | Method for determining impact force of honeycomb buffer in landing buffering process |
| CN106800095A (en) * | 2015-11-26 | 2017-06-06 | 中国飞行试验研究院 | Telescopic landing gear calibration load based on buffer compression travel determines method |
| CN206719572U (en) * | 2017-03-31 | 2017-12-08 | 南京航空航天大学 | A kind of Retracting Or Lowering Aerodynamic Loads On Landing Gear analogue means |
| CN107782481A (en) * | 2016-08-30 | 2018-03-09 | 中国飞行试验研究院 | A kind of ground surface calibration method of two-wheel column support type nose-gear torsion beam load |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0609049D0 (en) * | 2006-05-08 | 2006-06-14 | Airbus Uk Ltd | Method and apparatus for applying bending load to an axle of an aircraft landing gear |
| US9045237B2 (en) * | 2010-08-31 | 2015-06-02 | C. Kirk Nance | Automated inspection of aircraft landing gear internal fluid levels |
| US8565968B2 (en) * | 2010-08-31 | 2013-10-22 | C. Kirk Nance | Automated inspection of aircraft landing gear internal fluid levels |
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2018
- 2018-10-26 CN CN201811264151.2A patent/CN109703778B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6317956B1 (en) * | 1999-06-11 | 2001-11-20 | George R. Blankenship | Method and apparatus for removing an aircraft strut from an aircraft having retractable landing gear |
| CN104573347A (en) * | 2014-12-26 | 2015-04-29 | 北京空间机电研究所 | Method for determining impact force of honeycomb buffer in landing buffering process |
| CN106800095A (en) * | 2015-11-26 | 2017-06-06 | 中国飞行试验研究院 | Telescopic landing gear calibration load based on buffer compression travel determines method |
| CN107782481A (en) * | 2016-08-30 | 2018-03-09 | 中国飞行试验研究院 | A kind of ground surface calibration method of two-wheel column support type nose-gear torsion beam load |
| CN206719572U (en) * | 2017-03-31 | 2017-12-08 | 南京航空航天大学 | A kind of Retracting Or Lowering Aerodynamic Loads On Landing Gear analogue means |
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| CN109703778A (en) | 2019-05-03 |
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