• Title/Summary/Keyword: Landing Gear

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Nose Landing Gear Drop-test Simulation using Numerical Analysis about Orifice (오리피스 유량해석을 통한 전륜 착륙장치의 착륙성능평가)

  • Hwang, Jaeup;Bae, Jaesung;Hwang, Jaihyuk;Hong, Yehsun;Park, Sangjoon;Chung, Taekyong
    • Journal of Aerospace System Engineering
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    • v.8 no.1
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    • pp.18-23
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    • 2014
  • This thesis is simulated a aircraft nose landing gear drop-test. flow rate-to-pressure difference characteristics of damping orifices for a nose landing gear is investigated by CFD analyses. Orifice is kind of poppet valve type. it is simulated pressure drop with variable orifice area. it is simulated landing gear model by using ADAMS with CFD result. It's performance evaluated landing gear drop-test and analyzed the results.

소형항공기용 고정식 착륙장치의 동적특성에 관한 연구

  • Choi, Sun-Woo;Ahn, Seok-Min
    • Aerospace Engineering and Technology
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    • v.3 no.2
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    • pp.191-196
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    • 2004
  • Most of studies for landing gear have been performed to analyze the shock absorbing characteristics of oleo-pneumatic struts. But it is not easy to solve the dynamic specific properties of spring type composite landing gear using a present method. The shock absorbing abilities of oleo-pneumatic landing gear strut are under influence of the internal design method on the strut rather than the landing gear structure itself. Unlike oleo type, spring type composite strut absorbs the shock with structural strength and dynamic characteristics of the strut's material and shape. The tests and analysis for the shock absorbing rate and dynamic behavior of the spring type composite fixed landing gear for 4 seats small aircraft, have been performed using landing gear drop test rig.

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Stress Analysis of Plate-Spring-Type Landing Gear Materials (판스프링형 랜딩기어의 재질에 따른 응력 해석)

  • Kim, Kyeong-Hwan;Lee, Young-Shin;Han, Jae-Do
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.3
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    • pp.303-308
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    • 2014
  • Aircraft are an indispensable mode of modern transportation. They are also used as in a wide variety of other fields. For example, aircraft are used for accommodating passengers, carrying freight, and for military reconnaissance. Aircraft ground operations include landing and taking off. During landing, a higher load is applied to the landing gear than during takeoff. The landing gear should absorb impact energy and prevent damage to the main body of the aircraft in the case of an accident. In this study, simulations were performed for two types of plate-spring-type landing gear: that made of composite materials and that constructed with aluminum. The structural safety of landing gear made of each material was also evaluated.

Drop Test for the UAV Landing Gear Performance Verification (무인정찰기 착륙장치 성능입증을 위한 낙하시험)

  • Shin, Jeong-Woo;Lee, Seung-Gyu;Yang, Jin-Yeol;Kim, Sung-Joon;Hwang, In-Hee;Chung, Sang-Joon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.250-254
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    • 2011
  • Main role of landing gear is to absorb the energy which is generated by aircraft lanidng and ground maneuvering. Generally, in order to absorb the impact energy during landing, oleo-pneumatic type shock absorber is used for aircraft landing gear. Oleo-pneumatic type shock absorber has a good energy absorbing efficiency and is light in weight because its structure is relatively simple. For the landing gear development, it is necessary to conduct drop test in order to verify shock absorbing performance. In the drop test, first, gas spring curve verification tests are conducted. Then, limit and reserve energy absorption drop tests are performed based on the STANAG 4671. The drop tests results with performance analysis results are presented.

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A Study on the Effect Influencing on the Performance of Air Plane by the Air Flow due to Landing Gear Configuration (랜딩기어 형상에 따른 공기 유동으로 인한 항공기 성능에 미치는 영향에 관한 연구)

  • Han, Moonsik;Cho, Jaeung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.6
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    • pp.35-40
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    • 2017
  • The aerodynamic performance of airplane is different according to the configuration of landing gear. As the drag becomes different according to this configuration, the flow stream of air must be smooth at taking off and landing. In this study, the configuration of landing gear was designed each in order to enhance the energy efficiency of airplane. Five models were compared in total at analysis. The magnitudes of drag and pressure became different and the air pressure of wake were changed due to the configuration. So, the air pressure due to the flow velocity and the air resistance happening at the rear can be estimated according to the configuration of landing gear. It is thought to improve the performance of airplane through the result of this study.

On the Approximate Solution of Aircraft Landing Gear under Nonstationary Random Excitations (비정상 랜덤 가진력을 받는 항공기 착륙장치의 응답해석 기법연구)

  • 황재혁;유병성;공병식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.345-351
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    • 1997
  • The motion of an aircraft landing gear over rough runway at variable speed is nonstationary. hi this paper, a method for the computation of nonstationary response variance is presented which uses a state space form for the combination of landing gear and runway excitation. The dynamic characteristics of the landing gear under nonstationazy random excitations has also been analyzed using the proposed method. The formulation is for linear systems of arbitrary order and allows any deterministic velocity history.

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Force Control of Main Landing Gear using Magneto-Rheological Damper (MR 댐퍼를 이용한 주륜 착륙장치 하중제어기법 연구)

  • Hyun, Young-O;Hwang, Jae-Up;Hwang, Jae-Hyuk;Bae, Jae-Sung;Lim, Kyoung-Ho;Kim, Doo-Man;Kim, Tae-Wook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.4
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    • pp.344-349
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    • 2009
  • To improve performance of the main landing gear for helicopters, a semi-active control landing gear is introduced in this paper. An MR damper based on commercial finite element electromagnetic field analysis of an electromagnet has been adapted the shock absorber. Force control algorithm (which maintains constantly the sum of air spring force and damping force as internal forces) which keep the sum of air spring force and damping force constant during landing, has been used for the controller, applied to control the semi-active landing gear. A series of drop simulations using ADAMS has been done with the passive, sky-hook control type, and force control type landing gears. The result of each simulation has been compared to evaluate the landing performance of the proposed force control type landing gear.

Dynamic Analysis of a Helicopter Landing Gear with Considering Flexible Structural Modes (동체의 유연성을 고려한 헬기 착륙장치의 동특성 해석 연구)

  • Hyun, Young-O;Bae, Jae-Seoung;Kim, Young-Seok;Hwang, Jae-Up;Lim, Kyoung-Ho;Kim, Doo-Man;Kim, Tae-Wook;Hwang, Jai-Hyuk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.15 no.4
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    • pp.33-37
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    • 2007
  • In this paper, a dynamic analysis of a helicopter landing gear with considering flexible structural modes has been investigated. The main body of the helicopter has been modeled as a flexible body using FEM code, then a few selected vibration modes of the helicopter main body have been used as basis for the dynamic analysis of the helicopter landing gear. The simulation of dynamic analysis was carried out on the base of ADAMS aircraft module. It has been found by a series of simulation that the flexible structural modes has a significant effect on the dynamic characteristics of helicopter landing gear as the flexibility of the main body is increased.

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Dynamic Analysis of Aircraft Landing Gear under Nonstationary Random Excitations (비정상 랜덤 가진력을 받는 항공기 착륙장치의 동특성 해석)

  • 황재혁;유병성;박명호
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.60-68
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    • 1997
  • The motion of an aircraft landing gear over rough runway at variable speed is nonstationary. In this paper a method for the computation of nonstationary response variance is presented which uses a state space form for the combination of landing gear and runway excitation. The dynamic characteristics of the landing gear under nonstationary random excitations has also been analyzed using the proposed method. The formulation is for linear systems of arbitrary order and allows any deterministic velocity history. It has been found by a series of simulation that correlation parameter, damping coefficients of landing gear and tire, and velocity profiles plays a prominent role on the dynamic characteristics.

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Landing Gear 2 Degree of Freedom Modeling and Optimization (착륙장치 2 자유도 동적 모델링 및 최적설계)

  • Lee, Seung-Gyu;Shin, Jeong-Woo;Kim, Tae-Uk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.23 no.1
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    • pp.56-61
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    • 2015
  • Because of kinematic complexities, nonlinear behavior, etc, the performance of oleo-pneumatic landing gear is predicted by qualified commercial softwares. While commercial softwares predict more exactly, it takes a long time to construct or modify a model. At initial design stage, design parameters can be determined quickly and exactly enough with simple 2 degree of freedom model of mass, spring and damping. 2 degree of freedom model can be easily applied to optimization and reliability analysis which takes repetitive computation. In this paper, oleo-pneumatic landing gear is modeled as a nonlinear 2 degree of freedom model. The analysis are compared with landing gear drop test. To determine design parameter, optimization problem is solved with genetic algorithm and 2 degree of freedom model.