Journal articles: 'Landing gear retraction'

1

Parat, Camille, Zu-Yun Li, and Jing-Shan Zhao. "Design and stiffness analysis of an overconstrained landing gear retraction mechanism with four side-stays." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 12 (January 13, 2019): 4421–35. http://dx.doi.org/10.1177/0954410018824509.

Full text

Abstract:

It is the first mission for a landing gear retraction system to extend the structure during the phases of take-off and landing of the flight. Besides, the structure should be available to improve the reliability, strength and stability of the system while reducing the influence of the landing gear on the total drag. However, a large number of airplane accidents are due to the malfunctions or failures of the landing gear retraction system. In this paper, a novel design of retraction system is proposed. Instead of having only one side-stay to execute the desired motion, this new design proposed an over-constrained mechanism with four side-stays, which augments the structural strength and stability of the landing gear system with six over constraints. With such configuration, a second actuating motor to retract the landing gear can be inserted regardless of the first actuator to augment the reliability on the execution of the mechanism. Analyses on the properties of the landing gear retraction system with four side-stays show that the landing gear strut has a vertical motion, which decreases the working and storage spaces used for the system. Finally, this paper examines the statics and the stiffness coefficients of the retraction system with respect to its structure parameters. This provides the optimum structure for the landing gear system in terms of strength and reliability.

APA, Harvard, Vancouver, ISO, and other styles

2

Liang, Yong, Kun Zhao, Yingchun Chen, Longjun Zhang, and Gareth J. Bennett. "An Experimental Characterization on the Acoustic Performance of Forward/Rearward Retraction of a Nose Landing Gear." International Journal of Aerospace Engineering 2019 (July 4, 2019): 1–11. http://dx.doi.org/10.1155/2019/4135094.

Full text

Abstract:

The modern undercarriage system of a large aircraft normally requires the landing gear to be retractable. The nose landing gear, installed in the front of the fuselage, is retracted either forward or rearward. In the forward/rearward retraction system, the landing gear is normally installed to the trailing/leading side of the bay. When the incoming flow passes the landing gear as well as the bay, the installation that corresponds to the forward/rearward retraction system has a significant impact on the coupling flow and the associated noise of the landing gear and the bay. In this paper, acoustic performance of the forward/rearward retraction of the nose landing gear was discussed based on experiment. The landing gear bay was simplified as a rectangular cavity, and tests were conducted in an aeroacoustics wind tunnel. The cavity oscillation was first analyzed with different incoming speeds. Then, the landing gear model was installed close to the trailing and the leading side of the cavity, respectively. It was observed that installation close to the leading side can help disturb the shear layer so as to suppress the oscillation, while the trailing one can make the landing gear itself produce lower noise. Accordingly, conclusions on the acoustic performance of the forward/rearward retraction of the nose landing gear are made.

APA, Harvard, Vancouver, ISO, and other styles

3

Ma, Jun Gong, Zhong Zhi Wu, Hao Ran Guo, and Jia Li. "Design and Simulation Study of a Certain Landing Gear Loading Simulation System." Advanced Materials Research 871 (December 2013): 69–76. http://dx.doi.org/10.4028/www.scientific.net/amr.871.69.

Full text

Abstract:

The landing gear ground loading tests is a vital part before flight. As the motion of landing gear is three-dimensional motion,the traditional loading method cannot effectively simulate the pneumatic load on the ground. In order to simulate the load in the process of retraction/extension, a loading simulation system is proposed, including retractile system, position follow-up system and force servo loading system. This paper analyzes retraction/extension mechanism of the landing gear and builds up its mathematical model. A co-simulation model is developed in which the hydraulic system model and control system are built in software AMESim, the mechanical system of test platform model is built in software ADAMS. The results of the simulation confirm that the loading simulation system is feasible and provide the basis for building hardware platform.

APA, Harvard, Vancouver, ISO, and other styles

4

NICOLIN, Ilie, and Bogdan Adrian NICOLIN. "Research on the nose landing gear of a military training aircraft." INCAS BULLETIN 12, no. 4 (December 4, 2020): 249–59. http://dx.doi.org/10.13111/2066-8201.2020.12.4.23.

Full text

Abstract:

This paper presents the analysis of the landing gear configurations and the proposal of a solution for a military training aircraft. The paper presents both landing gears: nose and main because they are inextricably linked. The nose landing gear of military aircraft is a complex system composed of structural elements, electric and hydraulic components, energy absorption components, aircraft tire wheels etc., which is dimensioned according to the weight of the aircraft. Additional components attached to the nose landing gear include a landing gear extension and retraction mechanism and a steering system. The landing gear must withstand the weight of the aircraft in all phases of take-off (maximum weight: fuel, armament, ammunition, other equipment, flight crew etc.) and landing (impact from landing and a lower weight after completing the mission due to fuel consumption and ammunition use).

APA, Harvard, Vancouver, ISO, and other styles

5

Shams, Taimur Ali, Syed Irtiza Ali Shah, Muhammad Ayaz Ahmad, Kashif Mehmood, Waseem Ahmad, and Syed Tauqeer ul Islam Rizvi. "Selection Methodology of an Electric Actuator for Nose Landing Gear of a Light Weight Aircraft." Applied Sciences 10, no. 23 (December 6, 2020): 8730. http://dx.doi.org/10.3390/app10238730.

Full text

Abstract:

Landing gear system of an aircraft enables it to take off and land with safety and comfort. Because of the horizontal and vertical velocity of aircraft, upon landing, the complete aircraft undergoes different forcing functions in the form of the impact force that is absorbed by landing gears, shock absorbers, and actuators. In this research, a selection methodology has been proposed for an electrical actuator to be installed in the retraction mechanism of nose landing gear of an aircraft having 1600 kg gross takeoff weight. Nose landing gear and its associated components, like strut and shock absorbers, were modeled in CAD software. Analytical expressions were then developed in order to calculate the actuator stroke, translational velocity, force, and power for complete cycle of retraction, and some were subsequently compared with the computational results that were obtained using MSC ADAMS®. Air in the oleo-pneumatic shock absorber of nose landing gear was modeled as a nonlinear spring with equivalent spring constant, whereas hydraulic oil was modeled as a nonlinear damper with equivalent damping constant. The nose landing gear system was modeled as a mass-spring-damper system for which a solution for sinusoidal forcing functions is proposed. Finally, an electrical actuator has been selected, which can retract and extend nose landing gear, meeting all of the constraints of aircraft, like fuselage space, aircraft ground clearance, locking loads, power consumption, retraction and extension time, and dynamic response of aircraft. It was found that the selection of an electrical actuator is based upon the quantification of forces transmitted to electrical actuator during one point load at gross takeoff weight. The ability of retraction and extension time, as dictated by Federal Aviation Regulation, has also been given due consideration in the proposed methodology as significant criteria. The proposed system is now in the process of ground testing, followed by flight testing in the near future.

APA, Harvard, Vancouver, ISO, and other styles

6

Zhang, Li, Hong Nie, and Xiaohui Wei. "Tolerance Design and Robust Study for The Joint Clearances of Landing Gear Retraction Mechanisms." Applied Sciences 10, no. 14 (July 15, 2020): 4856. http://dx.doi.org/10.3390/app10144856.

Full text

Abstract:

Joint clearances inevitably affect the kinematic accuracy and robustness of landing gear retraction mechanisms. However, the complexity and uncertainty of the clearances lead to difficulty in establishing mathematic models and analyzing effects. In the interest of assessing the clearance effects on the kinematic accuracy of landing gears, an integrated tolerance theory is proposed in this paper. In the theory proposed, Jacobian–Torsor model is combined with robust analysis to establish the kinematic accuracy model and predict the influences of clearances. The overall steps to apply the theory presented in practice are given. A typical landing gear retraction mechanism is chosen for the case study and the results show that the tendencies of clearances can be observed. Through the process of tolerance design, robust study, and tolerance redesign, the kinematic accuracy is significantly improved. The integrated tolerance theory proposed and the study conducted will provide designers new insights for the clearance analysis of landing gear mechanisms.

APA, Harvard, Vancouver, ISO, and other styles

7

Zhou, Changcong, Mengyao Ji, Yishang Zhang, Fuchao Liu, and Haodong Zhao. "Mechanism reliability and sensitivity analysis of landing gear under multiple failure modes." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 39, no. 1 (February 2021): 46–54. http://dx.doi.org/10.1051/jnwpu/20213910046.

Full text

Abstract:

For a certain type of aircraft landing gear retraction-extension mechanism, a multi-body dynamic simulation model is established, and the time-dependent curves of force and angle are obtained. Considering the random uncertainty of friction coefficient, assembly error, and the change of hinge wear under different retraction times, the reliability model is built including three failure modes of landing gear, i.e. blocking failure, positioning failure and accuracy failure. Based on the adaptive Kriging model, the reliability and sensitivity of retraction-extension system under the condition of single failure mode and multiple failure modes in series are analyzed, and the rule of reliability and sensitivity changing with the number of operations is given. The results show that the system failure probability of landing gear mechanism tends to decrease first and then increase when considering the given information of random factors, and the influences of random factors on the failure probability vary with the number of operations. This work provides a viable tool for the reliability analysis and design of landing gear mechanisms.

APA, Harvard, Vancouver, ISO, and other styles

8

De Stefano, Giuliano, Nunzio Natale, Giovanni Paolo Reina, and Antonio Piccolo. "Computational Evaluation of Aerodynamic Loading on Retractable Landing-Gears." Aerospace 7, no. 6 (May 29, 2020): 68. http://dx.doi.org/10.3390/aerospace7060068.

Full text

Abstract:

Computational fluid dynamics is employed to evaluate the mean aerodynamic loading on the retractable landing-gears of a regional transport commercial aircraft. The mean turbulent flow around simplified landing-gear systems including doors is simulated by using the Reynolds-averaged Navier–Stokes approach, where the governing equations are solved with a finite volume-based numerical method. Using a dynamic meshing method, the computational grid is automatically and continuously adapted to the time-changing geometry, while following the extension/retraction of the landing-gear systems. The temporal evolution of the aerodynamic forces on both the nose and the main landing-gears, along with the hinge moments of the doors, is numerically predicted. The proposed computational modeling approach is verified to have good practical potential when compared with reference experimental data provided by the Leonardo Aircraft structural loads group.

APA, Harvard, Vancouver, ISO, and other styles

9

Liu, Ji Hong, Ying Zhong Pang, and Yu Ming Zhu. "Multi-Domain Unified Modeling and Simulation for Aircraft Landing Gear Using Modelica." Advanced Materials Research 311-313 (August 2011): 2457–60. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.2457.

Full text

Abstract:

Modern products become more and more complex, the modeling and simulation of them are carried out with different software on heterogeneous platforms, which always caused the heterogeneous data, separated disciplines and cannot obtain the result of unified model correctly. Therefore, a Modelica-based modeling and simulation method for aircraft landing gear is proposed. The landing gear library based on Modelica was established. The unified physical model of landing gear which is composed of structural, thermodynamics and hydromechanics disciplines is constructed. The aircraft landing process, the track of retraction mechanism and the impact work amount of the shock absorber are obtained through multi-domain unified simulation, which provides references for deisgners.

APA, Harvard, Vancouver, ISO, and other styles

10

Yin, Yin, Nie Hong, Ni Huajin, and Zhang Ming. "Reliability Analysis of Landing Gear Retraction System Influenced by Multifactors." Journal of Aircraft 53, no. 3 (May 2016): 713–24. http://dx.doi.org/10.2514/1.c033333.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Wei, Xiao Hui, Yin Yin, Heng Chen, and Hong Nie. "Modeling and Simulation of Aircraft Nose Landing Gear Emergency Lowering Using Co-Simulation Method." Applied Mechanics and Materials 215-216 (November 2012): 1213–18. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.1213.

Full text

Abstract:

This paper builds dynamical models and hydraulic system models of retraction/lowering of some regional aircraft nose landing gear respectively based on the software LMS VL motion and AMESim. The simulation analysis result was proved to be credible by checking with that of ground test. The peak oil return pressure with the critical damping force can be obtained by analyzing the hydraulic damping characteristic of actuator cylinder during landing gear emergency lowering based on methods of estimation and co-simulation. The results indicate that the damping characteristic of actuator cylinder plays an important role in emergency lowering. Only when the damping force breaks through the critical value, can the landing gear succeed in emergency lowering and being locked. However, the little damping force will result in great impact load while lowering. Thus, damping force should be changed only when emergency lowering.

APA, Harvard, Vancouver, ISO, and other styles

12

Cahyono, Mohammad Ardi, and Rahmat Suwandi. "PEMODELAN MATEMATIK SISTEM HIDROLIK PADA MAIN LANDING GEAR EXTENSION DAN RETRACTION PESAWAT BOEING 737-900ER DENGAN PROGRAM MATLAB-SIMULINK." Angkasa: Jurnal Ilmiah Bidang Teknologi 9, no. 1 (August 22, 2017): 43. http://dx.doi.org/10.28989/angkasa.v9i1.110.

Full text

Abstract:

The problem that often arises in the hydraulic system when the main landing gear is done extension and retraction is the control o f the hydraulic motion and the fluid motion is very big influence on the hydraulic work process where the fluid flow must be ensured or arranged in such a way as to work properly. To overcome this problem, a mathematical modeling system is used to create a representation or an imitation o f the actual system, which links the output o f the system with its input in a mathematical relationship and its parameter values. The research was conducted by observation method and literature study to obtain the data and its calculation. The results o f this study obtained a description o f the response and dynamic characteristics o f the PID controller in the transfer function o f the hydraulic system when the main landing gear extension and retraction o f the nearest Boeing 737-900ER aircraft is the 5th time experiment by inputting PID controller value P = 13 I = 4 D = 3 with an error value o f 0.01887 and an overshoot o f1,0002. With a small error value or a 2% value limit and the response picture is not experiencing a large overshoot, then the picture o f the response in accordance with the expected in the 5th experiment where the error value o f 0.01887 and overshoot o f 1,0002. With an overview o f the response with this small overshoot then the accuracy o f the system will stop at the point corresponding to the actual system. By using this modeling, the response o f the main landing gear extension and retraction movements can be well studied thus providing a good understanding o f the performance of the hydraulic system.

APA, Harvard, Vancouver, ISO, and other styles

13

Zhang, Feng, Shiwang Tan, Leilei Zhang, Yameng Wang, and Yang Gao. "Fault Tree Interval Analysis of Complex Systems Based on Universal Grey Operation." Complexity 2019 (January 1, 2019): 1–8. http://dx.doi.org/10.1155/2019/1046054.

Full text

Abstract:

The objective of this study is to propose a new operation method based on the universal grey number to overcome the shortcomings of typical interval operation in solving system fault trees. First, the failure probability ranges of the bottom events are described according to the conversion rules between the interval number and universal grey number. A more accurate system reliability calculation is then obtained based on the logical relationship between the AND gates and OR gates of a fault tree and universal grey number arithmetic. Then, considering an aircraft landing gear retraction system as an example, the failure probability range of the top event is obtained through universal grey operation. Next, the reliability of the aircraft landing gear retraction system is evaluated despite insufficient statistical information describing failures. The example demonstrates that the proposed method provides many advantages in resolving the system reliability problem despite poor information, yielding benefits for the function of the interval operation, and overcoming the drawback of solution interval enlargement under different orders of interval operation.

APA, Harvard, Vancouver, ISO, and other styles

14

Smith, Leighton L. "Qualifying as an Expert Witness and a Perspective on Negligence." Proceedings of the Human Factors Society Annual Meeting 36, no. 8 (October 1992): 616–20. http://dx.doi.org/10.1518/107118192786750953.

Full text

Abstract:

This article discusses the process of qualifying as an expert witness in court cases. The author's personal experience as a human factors expert witness in a representative case is described and used as an illustrative example. The role of the expert witness in typical injury litigations is described. The difficulty in convincing judges to allow such testimony by experts is also discussed. The value of human factors expert witness testimony is shown through the particulars of an inadvertent landing gear retraction accident lawsuit. In addition, a discussion of the negligence phase of these types of litigations is provided and it is demonstrated again using the landing gear case as illustration, how human factors expert witness testimony can be extremely integral to the judgment of negligence.

APA, Harvard, Vancouver, ISO, and other styles

15

Knowles, James A. C., Mark H. Lowenberg, Simon A. Neild, and Bernd Krauskopf. "A bifurcation study to guide the design of a landing gear with a combined uplock/downlock mechanism." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, no. 2172 (December 8, 2014): 20140332. http://dx.doi.org/10.1098/rspa.2014.0332.

Full text

Abstract:

This paper discusses the insights that a bifurcation analysis can provide when designing mechanisms. A model, in the form of a set of coupled steady-state equations, can be derived to describe the mechanism. Solutions to this model can be traced through the mechanism's state versus parameter space via numerical continuation, under the simultaneous variation of one or more parameters. With this approach, crucial features in the response surface, such as bifurcation points, can be identified. By numerically continuing these points in the appropriate parameter space, the resulting bifurcation diagram can be used to guide parameter selection and optimization. In this paper, we demonstrate the potential of this technique by considering an aircraft nose landing gear, with a novel locking strategy that uses a combined uplock/downlock mechanism. The landing gear is locked when in the retracted or deployed states. Transitions between these locked states and the unlocked state (where the landing gear is a mechanism) are shown to depend upon the positions of two fold point bifurcations. By performing a two-parameter continuation, the critical points are traced to identify operational boundaries. Following the variation of the fold points through parameter space, a minimum spring stiffness is identified that enables the landing gear to be locked in the retracted state. The bifurcation analysis also shows that the unlocking of a retracted landing gear should use an unlock force measure, rather than a position indicator, to de-couple the effects of the retraction and locking actuators. Overall, the study demonstrates that bifurcation analysis can enhance the understanding of the influence of design choices over a wide operating range where nonlinearity is significant.

APA, Harvard, Vancouver, ISO, and other styles

16

Gu, Feng, Ji Hai Jiang, Fei Meng Diao, Quan Du, Lei Gao, Yan Nan Song, and Yan Li. "The Modeling and Simulation of Hydraulic Actuated Control System of Helicopter in Volumetric Speed Control." Applied Mechanics and Materials 779 (July 2015): 169–74. http://dx.doi.org/10.4028/www.scientific.net/amm.779.169.

Full text

Abstract:

Hydraulic generation system on helicopter generally consists of flight control hydraulic actuating circuit, landing gear retraction/extension hydraulic circuit, and wheel brake circuit. This paper studies on a volumetric speed control system applied in helicopter flight control actuating system. The system performance curve, deduced from the modeling, simulation and testing of the tail-actuating system, reveals that this volumetric speed control system meets the requirements of helicopter control system actuating.

APA, Harvard, Vancouver, ISO, and other styles

17

TAKAHASHI, Norio, Taku KONDO, Masayuki TAKADA, Kazuhiro MASUTANI, Shingo OKANO, and Mitsuhiro TSUJITA. "DEVELOPMENT OF PROTOTYPE ELECTRO-HYDROSTATIC ACTUATOR FOR LANDING GEAR EXTENSION AND RETRACTION SYSTEM." Proceedings of the JFPS International Symposium on Fluid Power 2008, no. 7-1 (2008): 165–68. http://dx.doi.org/10.5739/isfp.2008.165.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Chen, Jie, Cunbao Ma, and Dong Song. "Multiple failure prognosis of landing gear retraction/extension system based on H∞ filtering." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 229, no. 8 (September 24, 2014): 1543–55. http://dx.doi.org/10.1177/0954410014551973.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Chiariello, Antonio, Salvatore Orlando, Pasquale Vitale, Mauro Linari, Raffaele Longobardi, and Luigi Di Palma. "Development of a Morphing Landing Gear Composite Door for High Speed Compound Rotorcraft." Aerospace 7, no. 7 (June 30, 2020): 88. http://dx.doi.org/10.3390/aerospace7070088.

Full text

Abstract:

In the framework of fast rotorcraft, smoothness and flushness of external aerodynamic surfaces present challenges for high-speed conditions, where aerodynamics is the driver of helicopter performance. For AIRBUS-RACER helicopter the main landing gear trap doors are parts of the lower wing skins (in retracted configuration) affecting helicopter performance by minimizing the drag. Flushness requirements must not be in contrast with the functionally of the Landing gear system that must open and close the doors during the landing gear retraction-extension phases at moderately low velocity. To manage these goals, a novel design logic has been identified to support the trap doors development phase. The identified way to proceed needs of relevant numerical method and tool as well. This method is aimed at identifying the main landing gear composite compartment doors in pre-shaped configuration to match the smoothness and door-stopper engagements over each aerodynamic conditions. The authors propose a detailed non-linear Finite Element method, based on MSC Nastran (MSC Software, Newport Beach, US) SOL-400 solver in which the structure is modelled with deformable contact bodies in a multiple load step sequence, open door condition and pre-shaped, deformed under actuator pre-load, under flight load conditions. The method includes the entire pre-stressed field due to the preload and the actual door stiffness, considering the achieved large displacement to verify the most representative strain field during loads application. The paper defines a robust methodology to predict the deformation and ensure the most appropriate door “pre-bow” and pre-load, in order to achieve the desiderated structural shape that matches aerodynamic requirements. The main result is the identification of a pre-shaped doors configuration for the Airbus RACER Fast Rotorcraft.

APA, Harvard, Vancouver, ISO, and other styles

20

Chen, Jie, Senyao Chen, Zhenbao Liu, Caikun Luo, Zhengdong Jing, and Qingshan Xu. "Health Monitoring of Landing Gear Retraction/Extension System Based on Optimized Fuzzy C-Means Algorithm." IEEE Access 8 (2020): 219611–21. http://dx.doi.org/10.1109/access.2020.3042888.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Guo, Yueping. "Retraction notice to “A component-based model for aircraft landing gear noise prediction” [J. Sound Vib. 312 (2008) 801–820]." Journal of Sound and Vibration 333, no. 18 (September 2014): 4402. http://dx.doi.org/10.1016/j.jsv.2014.04.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Gorpenko, A. O., O. I. Semenets, O. M. Doniy, and K. O. Valuiska. "Effect of the chassis parts surface condition from high-strength titanium alloy VT-22 in the process of fatigue tests." Uspihi materialoznavstva 2021, no. 2 (June 1, 2021): 45–53. http://dx.doi.org/10.15407/materials2021.02.045.

Full text

Abstract:

The research focuses on the influence of the surface condition on the resource of high-strength titanium alloy VT-22 landing gear details during fatigue tests. The tests were performed on special facilities that simulate the workload on a rod detail at the stage of extending and retraction of the landing gear. Fatigue tests were performed on four rods. Rods № 1-3 were destroyed at the lugs level, rod №4 withstood the entire cycle of loads, and was examined in an undamaged state. It was found that the cause of the failure of the rod №1 was axial play formation as a result of bracket lug deformation, which led to shock loads on the lug of the rod №1 during the tests. The destruction of the rod №2 could be caused by the shock axial loads due to changes in the characteristics and load values of the facility on the rod №2. The priority factor influencing the premature failure of the rod №3 was the high risks from surface machining in the most loaded part of the rod №3, namely at the R-junction of the cylindrical part to the lug. The presence of surface defects formed during the manufacturing stage, as well as the presence of deep scratches in the area with high load reduce the life of rod № 3 fivefold compared to the undamaged rod № 4, which had no visible surface defects. Surface damage detected in the non-chromized area of the rods can be eliminated by blasting with subsequent surface polishing, which will provide the required resource of the detail (rod № 4). Keywords: high-strength titanium alloy VT-22, rod, fatigue tests, surface defects, structure of the surface layer.

APA, Harvard, Vancouver, ISO, and other styles

23

Zhu, Wu Feng, Zhong Yan, and Qing Wei Xin. "Research on Influence Factors of Landing Gear Retractile Hydraulic System Performance Degradation." Applied Mechanics and Materials 599-601 (August 2014): 409–12. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.409.

Full text

Abstract:

Simulation model of landing gear hydraulic system is built based on AMESim, several key influence factors of performance degradation of landing gear hydraulic system are analyzed, such as changes of restrictor orifice diameter, initial pressure of accumulator, viscosity and gas percentage of oil , etc. The simulation results bring valuable reference to aircraft maintenance.

APA, Harvard, Vancouver, ISO, and other styles

24

Zhang, Jun, Bing Zhang, and Rong Gang Yu. "Simulation-Based Reliability Analysis for Kinematic Accuracy of Retracting Mechanism of Landing Gear." Applied Mechanics and Materials 215-216 (November 2012): 754–57. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.754.

Full text

Abstract:

A simulation-based reliability analysis approach for kinematics accuracy of retracting mechanism is presented. The parametric variable model with linkage dimension error and joint clearance of retracting mechanism is modeled in ADAMS, adopting the Monte Carlo simulation method to analysis the influence of kinematic accuracy. The flowchart of the approach has been presented. Finally, the retracting mechanism is taken as an example to validate the proposed method. The results show that it is more accurate than the traditional methods.

APA, Harvard, Vancouver, ISO, and other styles

25

Lockard, David P., William M. Humphreys, Mehdi R. Khorrami, Ehab Fares, Damiano Casalino, and Patricio A. Ravetta. "Comparison of computational and experimental microphone array results for an 18% scale aircraft model." International Journal of Aeroacoustics 16, no. 4-5 (July 2017): 358–81. http://dx.doi.org/10.1177/1475472x17718724.

Full text

Abstract:

An 18% scale semispan model is used as a platform for examining the efficacy of microphone array processing using synthetic data from numerical simulations. Two hybrid Reynolds-Averaged-Navier-Stokes/Large-Eddy-Simulation (RANS/LES) codes coupled with Ffowcs Williams–Hawkings solvers are used to calculate 97 microphone signals at the locations of an array employed in the NASA Langley Research Center 14 × 22 tunnel. Conventional, DAMAS, and CLEAN-SC array processing is applied in an identical fashion to the experimental and computational results for three different configurations involving deploying and retracting the main landing gear and a part-span flap. Despite the short time records of the numerical signals, the beamform maps are able to isolate the noise sources, and the appearance of the DAMAS synthetic array maps is generally better than those from the experimental data. The experimental CLEAN-SC maps are similar in quality to those from the simulations indicating that CLEAN-SC may have less sensitivity to background noise. The spectrum obtained from DAMAS processing of synthetic array data is nearly identical to the spectrum of the center microphone of the array, indicating that for this problem array processing of synthetic data does not improve spectral comparisons with experiment. However, the beamform maps do provide an additional means of comparison that can reveal differences that cannot be ascertained from spectra alone.

APA, Harvard, Vancouver, ISO, and other styles

26

"Nose landing gear retraction." Aircraft Engineering and Aerospace Technology 72, no. 5 (October 2000). http://dx.doi.org/10.1108/aeat.2000.12772eab.013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Parat, Camille, Zu-Yun Li, and Jing-Shan Zhao. "Design and Folding/Unfolding Dynamics of an Over-Constrained Airplane's Landing Gear With Four Side Stays." Journal of Mechanisms and Robotics 11, no. 1 (November 12, 2018). http://dx.doi.org/10.1115/1.4041485.

Full text

Abstract:

This paper introduces the design of a specific landing gear retraction system presenting a mechanism with four redundant side stays and examines its dynamic behavior during the folding and unfolding processes. First, a concept design of a four-side-stay landing gear retraction system is presented. To get the particular motion during folding and unfolding, the main kinematics parameters are given. Then, the influence of the side stay's kinematic redundancy on the mechanism parameters is examined. Because the mechanism is overconstrained, the allowable parameters belong to a specific region of the space called feasible region. Finally, a dynamic analysis of the over-constrained system is executed by using the Newton–Euler approach and compliant equations. Numerical simulations indicate that this kind of landing gear retraction system equitably share the loads between different side stays, and therefore, the total load at one side stay is greatly reduced.

APA, Harvard, Vancouver, ISO, and other styles

28

Chinvorarat, Sinchai, and Pumyos Vallikul. "A novel retractable landing gear of a light amphibious airplane design, synthesis, analysis, and implementation." Aircraft Engineering and Aerospace Technology ahead-of-print, ahead-of-print (August 27, 2021). http://dx.doi.org/10.1108/aeat-10-2020-0237.

Full text

Abstract:

Purpose The purpose of this paper is to present a novel retractable main landing gear for a light amphibious airplane, while the design, synthesis and analysis are given in details for constructing the main landing gear. Design/methodology/approach The constraint three-position synthesis has given the correct path of all linkages that suitably fit the landing gear into the compartment. The additional lock-link is introduced into the design to ensure the securement of the mechanism while landing. Having the telescopic gas-oil shock strut as a core element to absorb the impact load, it enhances the ability and efficiency to withstand higher impact than others type of light amphibious airplane. Findings By kinematics bifurcation analysis, the optimized value of the unlock spring stiffness at 90 N/m can be found to tremendously reduce the extended-retracted linear actuator force from 500 N to 150 N at the beginning of the retraction sequence. This could limit the size and weight of the landing gear actuator of the light amphibious airplane. Practical implications The drop test of the landing gear to comply with the ASTM f-2245 (Standard Specification for Design and Performance of a Light Sport Airplane) reveals that the novel landing gear can withstand the impact load at the drop height determined by the standard. The maximum impact loading 4.8 G occurs at the drop height of 300 mm, and there is no sign of any detrimental or failure of the landing gear or the structure of the light amphibious airplane. The impact settling time response reaches the 2% of steady-state value in approximately 1.2 s that ensure the safety and stability of the amphibious airplane if it subjects to an accidentally hard landing. Originality/value This paper presents unique applications of a retractable main landing gear of a light amphibious airplane. The proposed landing gear functions properly and complies with the drop test standard, ensuring the safety and reliability of the airplane and exploiting the airworthiness certification process.

APA, Harvard, Vancouver, ISO, and other styles

29

HUANG, Chen, Yan-hui LIU, and Yu-hong JIA. "Design and Simulation of Aircraft Landing Gear Retraction Hydraulic Servo System." DEStech Transactions on Computer Science and Engineering, ammms (January 22, 2019). http://dx.doi.org/10.12783/dtcse/ammms2018/27238.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Zhang, Feng, Mingying Wu, Xinting Hou, Xinhe Wang, Cheng Han, Xiayu Xu, and Leilei Zhang. "Importance analysis based on universal grey operation for an aircraft landing gear retraction system." Journal of Intelligent & Fuzzy Systems, July 24, 2021, 1–11. http://dx.doi.org/10.3233/jifs-202248.

Full text

Abstract:

In order to improve the reliability and performance of landing gear retraction systems, this paper presents two importance analysis methods based on universal grey operation. According to the system principle and fault mechanisms, the fault tree of the retraction system was first established. The uncertainties of the bottom events were then described using the universal grey number to obtain the universal grey representation of the system failure probability. And compared with the traditional interval operation, the results show that universal grey operation can solve the problem of interval expansion with uncertainty. Importance analyses of the bottom events were then conducted based on the probability importance and the key importance. By comparing the two important indices of the bottom events, the larger the value is, the higher the importance is. It was found that the occurrence of the bottom events “pipeline oil leakage,” “pump motor damage,” and “oil pollution” had the greatest impact on system failure probability, thus determining the key weak links affecting system failure and indicating the most effective targets for improvement.

APA, Harvard, Vancouver, ISO, and other styles

31

Maryin, S. B., D. A. Potyanikhin, Wai Aung Phyo, and Ko Hlaing Min. "Research of the process of distributing the middle part of tubular blanks." Engineering Journal: Science and Innovation, no. 10 (106) (November 2020). http://dx.doi.org/10.18698/2308-6033-2020-10-2027.

Full text

Abstract:

A significant problem in the aircraft industry remains the production of reliable hydro-gas systems, such as flight control, landing gear retraction and release, wheel turn control of the front landing gear, control of air brakes and spoilers, engine thrust reversal control, et al., providing a high degree of performance and reliability. The article discusses the technological processes of manufacturing parts for hydro-gas systems of aircraft. Research has been carried out on the expansion of the middle part of thin-walled tubular billets by cold plastic deformation, which showed that the most dangerous is the middle part of the considered part of the billet, where there are significant tensile stresses. The reduction in tensile stresses that occurs when creating an ice retainer allows to increase in the expansion ratio. The application of new types of working bodies is proposed for transferring pressure to the deformation zone.

APA, Harvard, Vancouver, ISO, and other styles

32

Богоявленский, А., and A. Bogoyavlenskiy. "Metrological aspects of pre-flight anti-icing procedures for civil aircraft." World of measurement, September 25, 2019, 22–26. http://dx.doi.org/10.35400/1813-8667-2019-3-22-26.

Full text

Abstract:

Snow-ice deposits formed on the outer surfaces of aircrafts on the ground during parking can have a negative impact during take-off due to the deterioration of aerodynamic and flight performance, a significant and even critical decrease in lift, increased drag, blocking controls, difficulty or blocking of landing gear retraction, damage to the blades of inlet guide vanes and/or the blades of an engine compressor. To exclude the influence of snow and ice deposits, anti-icing treatment is performed, including their removal and/or protection from subsequent formation. For this purpose, special anti-icing machines (deicers), equipped with such means of instrumental control as counters of anti-icing fluid pumps, measuring scales of anti-icing fluid tanks, thermometers and pressure gauges for temperature and pressure measuring at the outlet of a spray nozzle, are used. The article deals with the metrological aspects of civil aircrafts anti-icing prior to flight.

APA, Harvard, Vancouver, ISO, and other styles

33

Богоявленский, А., and A. Bogoyavlenskiy. "Metrological aspects of pre-flight anti-icing procedures for civil aircraft." World of measurement, November 21, 2019, 26–31. http://dx.doi.org/10.35400/1813-8667-2019-4-26-31.

Full text

Abstract:

Snow-ice deposits formed on the outer surfaces of aircrafts on the ground during parking can have a negative impact during take-off due to the deterioration of aerodynamic and flight performance, a significant and even critical decrease in lift, increased drag, blocking controls, difficulty or blocking of landing gear retraction, damage to the blades of inlet guide vanes and/or the blades of an engine compressor. To exclude the influence of snow and ice deposits, anti-icing treatment is performed, including their removal and/or protection from subsequent formation. For this purpose, special anti-icing machines (deicers), equipped with such means of instrumental control as counters of anti-icing fluid pumps, measuring scales of anti-icing fluid tanks, thermometers and pressure gauges for temperature and pressure measuring at the outlet of a spray nozzle, are used. The article deals with the metrological aspects of civil aircrafts anti-icing prior to flight.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Landing gear retraction'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles