• Title, Summary, Keyword: Horizontal Stabilizer

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Improvement of Flight Safety by Horizontal Stabilizer Design Improvement of Rotorcraft (회전익 항공기 수평 안정판의 설계 개선을 통한 비행 안전성 향상)

  • Lee, Yoon-Woo;Kim, Dae-Han;Jang, Min-Wook;Hyun, Young-Jin;Lee, Sook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.134-141
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    • 2019
  • This paper is a study on design improvement of rotorcraft horizontal stabilizer. The rotorcraft horizontal stabilizer stabilizes the behavior of the pitch, yaw, etc. from the aircraft. Because of this role, horizontal stabilizers are a major component (Flight Safety Part) that affects flight safety on rotorcraft. However, when the rotorcraft was operated in domestic, cracks were found in the inner structure of the horizontal stabilizer and design improvement was needed. In this paper, we identified the two causes of the horizontal stabilizer crack defects through fracture analysis and structural analysis. The first is the tightening torque when the bolt is tightened, and the second is the lead-lag behavior of aircraft. In order to improve these two causes, bolt fastening method, flange structure and thickness were changed and composite ring was applied. In order to verify the design improvement, the structural analysis was performed and the structural strength was improved. Also Fatigue analysis of the internal structure (Rib 1) was performed and it was confirmed that the requirements were satisfied.

A Study on B737NG Aircraft Tail Strike during Takeoff (B737NG 항공기 이륙 중 미부지면접촉에 관한 연구)

  • Noh, Kun-Soo
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.17 no.4
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    • pp.70-75
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    • 2009
  • According to the aviation statistics, tail strike incidents and accidents are cyclic. Although many tail strikes occurred during takeoff, these are less than during landing cases. Many cases are related on human factors. In my opinion it is possible to analyze the causes of takeoff tail strikes to some extent. There are major casual factors of tail strike during takeoff such as; (1) Mis-trimmed horizontal stabilizer (2) premature rotation prior to $V_R$ (3) Excessive pitch up rate during rotation (4) Improper use of the flight director. Among these causes improper use of flight director is excluded in this paper because it is recommended that pilot should use flight director after airborne. So I analyzed the other three causes as following. Firstly, because mis-trimmed stabilizer is related to center of gravity(CG), the relationship between stabilizer and CG is reviewed. Secondly, concerned premature rotation prior to $V_R$ I reviewed the background of rotation speed($V_R$) establishment and analyzed theoretically what speed leads to tail strikes. Thirdly, concerning excessive pitch up rate during rotation I analyzed what excessive pitch up rate can decrease ground clearance while using FDR data.

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Estimation of Static Load Applied on Steam Generator Tubes (증기발생기 전열관에 작용되는 정적 하중 평가)

  • Park, Bumjin;Park, Jai Hak;Cho, Young Ki
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.7 no.1
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    • pp.35-40
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    • 2011
  • If a plugged tube in a steam generator is broken, it may damage nearby intact tubes. To prevent this damage, it is recommended that a stabilizer is installed into the plugged tube. However, the installation cost of a stabilizer is very high. So studies are required to determine the conditions on which the installation is necessary. For this purpose static loads and dynamic loads applied on a tube should be known to estimate the residual strength and remaining fatigue and wear life of a plugged tube. Two-dimensional and three-dimensional computational fluid dynamics (CFD) analyses are performed to obtain the drag coefficient for cross flow to a tube. Using the obtained drag coefficient, the static load can be estimated and the residual strength of a plugged tube can be calculated. An inclined flow problem is also analyzed and the vertical and horizontal forces are obtained and discussed.

H Control on the Optical Image Stabilizer Mechanism in Mobile Phone Cameras (이동통신 단말기 카메라의 손떨림 보정 장치의 H 제어)

  • Lee, Chibum
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.23 no.3
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    • pp.266-272
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    • 2014
  • This study proposes a closed-loop shaping control method with $H_{\infty}$ optimization for optical image stabilization (OIS) in mobile phone cameras. The image stabilizer is composed of a horizontal stage constrained by ball bearings and actuated by the magnetic force from voice coil motors. The displacement of the stage is measured by Hall effect sensors. From the OIS frequency response experiment, the transfer function models of the stage and Hall effect sensor were identified. The weight functions were determined considering the tracking performance, noise attenuation, and stability with considerable margins. The $H_{\infty}$ optimal controller was executed using closed-loop shaping and limiting the controller order, which should be less than 6 for real-time implementation. The control algorithm was verified experimentally and proved to operate as designed.

Parameter Estimation of a Small-Scale Unmanned Helicopter by Automated Flight Test Method (자동화 비행시험기법에 의한 소형 무인헬리콥터의 파라메터 추정)

  • Bang, Keuk-Hee;Kim, Nak-Wan;Hong, Chang-Ho;Suk, Jin-Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.9
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    • pp.916-924
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    • 2008
  • In this paper dynamic modeling parameters were estimated using a frequency domain estimation method. A systematic flight test method was employed using preprogrammed multistep excitation of the swashplate control input. In addition when one axis is excited, the autopilot is engaged in the other axis, thereby obtaining high-quality flight data. A dynamic model was derived for a small scale unmanned helicopter (CNUHELI-020, developed by Chungnam National University) equipped with a Bell-Hiller stabilizer bar. Six degree of freedom equations of motion were derived using the total forces and moments acting on the small scale helicopter. The dynamics of the main rotor is simplified by the first order tip-path plane, and the aerodynamic effects of fuselage, tail rotor, engine, and horizontal/vertical stabilizer were considered. Trim analysis and linearized model were used as a basic model for the parameter estimation. Doublet and multistep inputs are used to excite dynamic motions of the helicopter. The system and input matrices were estimated in the frequency domain using the equation error method in order to match the data of flight test with those of the dynamic modeling. The dynamic modeling and the flight test show similar time responses, which validates the consequence of analytic modeling and the procedures of parameter estimation.

Smart UAV Aft Fuselage Structural Analysis (스마트무인기 후방동체 구조해석)

  • Kim, Jin-Won;Lee, Sang-Uk
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.8-15
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    • 2006
  • In this report Smart UAV structural analysis of the aft fuselage is presented. Aft fuselage needs to have enough strength and stiffness considering loads of the Vertical and Horizontal Stabilizer together. It has a big hole for the purpose of engine exhaust duct on its side body. In addition, much attention is needed in high temperature region due to material strength deterioration.

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A Study on the Warning System of Aircraft for Obstacle Avoidance (지상장애물 회피를 위한 항공기 경고 시스템에 관한 연구)

  • Ham, Kwang-Keun;Choi, Jae-Duck;Huh, Uoong
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.5 no.1
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    • pp.65-79
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    • 1997
  • In this study, we deviced side warning system that is necessary to the ground operation of aircraft. The system consist of obstacle detection part, transmission part, receive part, and warning part. We used TOF(Time Of Flight) method using 40kHz ultrasonic wave as the obstacle detection part. The 447MHz RF module was applied to the transmission and receive part. The warning part is activated by the computer using received distance data. The detection system attach to the left/right side edge of main wing and horizontal stabilizer. We have decided 10m obstacle detection range. The result of experiment was satisfactory.

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A Study on the Elevator Spar Improvement for the Operating Aircraft (장기 운영항공기 승강타 날개보 구조개선 연구)

  • Shim, Daisung;Kim, Mantae;Yeom, Hyowon;Im, Dongmin;Kim, Youngjin;Uhm, Wonseop
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.6
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    • pp.675-680
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    • 2016
  • This is a study for the improvement of the defected elevator spar in operating aircraft. The elevator spar web holes were analyzed to find out the cause of the cracks. The fatigue striations were observed and the cracks occurred by the repetitive stresses during the elevator works. Also the outboard connection structure of the elevator and horizontal stabilizer was more weak shape than the inboard. The design changes were recommended and the analyses were performed to verify the improvement of the changed shapes.

Protoplast Formation, Regeneration and Reversion in Pleurotus ostreatus and P. sajor-caju (느타리버섯과 여름느타리버섯의 원형질체(原形質體) 나출(裸出)과 재생(再生))

  • Go, Seung-Joo;Shin, Gwan-Chull;Yoo, Young-Bok
    • The Korean Journal of Mycology
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    • v.13 no.3
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    • pp.169-177
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    • 1985
  • The studies were carried out to obtain the basic data for maximizing the protoplast yields from the mycelia of P. ostreatus and P. sajor-caju. Some factors affecting the regeneration of the protoplast of both species and the productivity of their reversion were also examined. The maximum yields of protoplasts were obtained from four days cultured mycelia of both species on cellophan membrane placed on the surface of PSA or MCM media in a petri dish. The optimal concentration of lytic enzyme Novozym 234 for protoplast releasing was 5 mg per ml of 0.5 M phosphate buffer solution with 0.6 M sucrose or 0.6 M $MgSO_4$ at pH 6.0. The greatest number of protoplasts was released 3 hours after incubation of the mycelia of P. ostreatus and after 4 hours for the P. sajor-caju in the lytic enzyme solution. Among the osmotic stabilizer solutions tested 0.6 M sucrose and 0.6 M KCl showed the best regeneration rates of the protoplasts of both species. When 0.75 % agar solution was over-layed on the regeneration media immediately after inoculation of the protoplast the regeneration rates were greatly enhanced. The ampicillin added to the agar solution prevented bacteria from infection. The reverted isolates produced the sporophores and basidial spores just like their parents without any mutations when they were cultivated in a broad mouth bottle with sawdust substrates.

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