• Title/Summary/Keyword: Airframe

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Design Modification of Airframe Shape for Ultra Light Quad-Rotor Development (초소형 쿼드로터 개발을 위한 기체형상 설계변경)

  • Park, Dae-Jin;Lee, Sangchul;Park, Saeng-Jin;Song, Tae-Hun
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.25 no.4
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    • pp.44-51
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    • 2017
  • An ultra light quad-rotor is utilized in various areas for military and commercial purpose. Especially, the airframe shape is designed with various airframe size, weight and purpose. In this paper, the initial airframe shape of the quad-rotor was designed and manufactured. Flight test was conducted for the quad-rotor. The design modification of airframe shape was conducted to meet design requirement. By changing design, weight of airframe structure was reduced and payloads were placed to the best position. By reinforcing ribs and reducing vehicle's legs, the durability of airframe structure was enhanced.

Aerodynamic Simulation of Rotor-Airframe Interaction by the Momentum Source Method (모멘텀 소스 방법을 이용한 로터-기체간의 간섭작용 해석)

  • Kim, Young-Hwa;Park, Seung-O
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.2
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    • pp.113-120
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    • 2009
  • To numerically simulate aerodynamics of rotor-airframe interaction in a rigorous manner, we need to solve the Navier-Stokes system for a rotor-airframe combination in a single computational domain. This imposes a computational burden since rotating blades and a stationary body have to be simultaneously dealt with. An efficient alternative is a momentum source method in which the action of rotor is approximated as momentum source in a stationary mesh system built around the airframe. This makes the simulation much easier. The magnitude of the momentum source is usually evaluated by the blade element theory, which often results in a poor accuracy. In the present work, we evaluate the momentum source from the simulation data by using the Navier-Stokes equations only for a rotor system. Using this data, we simulated the time-averaged steady rotor-airfame interaction and developed the unsteady rotor-airframe interaction. Computations were carried out for the simplified rotor-airframe model (the Georgia Tech configuration) and the results were compared with experimental data. The results were in good agreement with experimental data, suggesting that the present approach is a usefull method for rotor-airframe interaction analysis.

A Study on the Selection of Aircraft MRO using AHP (계층분석방법을 이용한 항공기 기체 MRO 업체 선정요인에 관한 연구)

  • Choi, Sejong;Kim, Woojin
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.23 no.4
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    • pp.82-88
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    • 2015
  • Airframe maintenance is regarded the most important maintenance action in airlines as the aircraft is the most valuable asset in their operation though the volume of airframe maintenance is the last in MRO market. In the selecting process of airframe MRO provider many kinds of evaluation criteria should be considered such as quality, expenses, TAT, capability, and customer support. This paper will suggest the way to select the airframe MRO in airlines and MRO business sectors using AHP.

Roll Angle Estimation of a Rolling Airframe Using a GPS and a Roll Rate Gyro (단일 GPS와 롤각속도계를 이용한 롤 회전 비행체의 롤자세각 추정)

  • Hong, Ju-Hyeon;Kim, Dusik;Ryoo, Chang-Kyung;Lee, Chang-Hun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.2
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    • pp.133-140
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    • 2015
  • In this paper, a roll angle estimation method of a rolling airframe using a low grade GPS and a roll rate gyro is proposed. The strength of the received signal of the GPS antenna attached on the rolling airframe is maximized when the GPS satellite is placed on the plane determined by the x-axis of the rolling airframe and the GPS antenna axis. Under the assumption that the x-axis of the rolling airframe is coincident with its velocity vector, the roll angle of the rolling airframe is calculated from the relative position vector of the satellite to the GPS when the GPS signal strength becomes maximum. The Kalman filter combined with a roll rate gyro is introduced to increase the determination accuracy of the roll angle. The performance of the proposed method is verified via 6-DOF simulations.

Active Airframe Vibration Control Simulations of Lift-offset Compound Helicopters in High-Speed Flights (고속 비행의 Lift-offset 복합형 헬리콥터 기체의 능동 진동 제어 시뮬레이션)

  • Hong, Sung-Boo;Kwon, Young-Min;Kim, Ji-Su;Lee, Yu-Been;Park, Byeong-Hyeon;Shin, Hyun-Cheol;Park, Jae-Sang
    • Journal of the Korea Institute of Military Science and Technology
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    • v.24 no.4
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    • pp.357-367
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    • 2021
  • This paper studies the simulations of active airframe vibration controls for the Sikorsky X2 helicopter with a lift-offset coaxial rotor. The 4P hub vibratory loads of the X2TD rotor are obtained from the previous work using a rotorcraft comprehensive analysis code, CAMRAD II. The finite element analysis software, MSC.NASTRAN, is used to model the structural dynamics of the X2TD airframe and to analyze the 4P vibration responses of the airframe. A simulation study using Active Vibration Control System(AVCS) with Fx-LMS algorithm to reduce the airframe vibrations is conducted. The present AVCS is modeled using MATLAB Simulink. When AVCS is applied to the X2TD airframe at 250 knots, the 4P longitudinal and vertical vibration responses at the specified airframe positions, such as the pilot seat, co-pilot seat, engine deck, and prop gearbox, are reduced by 30.65 ~ 94.12 %.

Airframe Structure Development of Solar-powered HALE UAV EAV-3 (고고도 장기체공 태양광 무인기 EAV-3 기체구조 개발)

  • Shin, Jeong Woo;Park, Sang Wook;Lee, Sang Wook;Kim, Tae-Uk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.25 no.3
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    • pp.35-43
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    • 2017
  • Research for solar-powered high altitude long endurance(HALE) UAV was conducted by Korea Aerospace Research Institute(KARI), and the EAV-3 with 19.5m wing span was developed. For HALE flight, aircraft should be lightly designed. Especially, airframe structure that accounts for a large portion of the total weight of aircraft should be lightweight. In this paper, development process of airframe structure for solar-powered HALE UAV, EAV-3, is described briefly. Domestic developed T-800 grade CFRP(Carbon Fiber Reinforced Plastic) composite material with high modulus and strength was used to design main load carrying structures. Flightloads analysis that takes into account large structural deformation was carried out. Stress and flutter analyses for airframe structure sizing were conducted. Static strength test for main wing and aircraft ground vibration test were conducted successfully and structural integrity was secured.

Navier-Stokes Simulation of Unsteady Rotor-Airframe Interaction with Momentum Source Method

  • Kim, Young-Hwa;Park, Seung-O
    • International Journal of Aeronautical and Space Sciences
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    • v.10 no.2
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    • pp.125-133
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    • 2009
  • To numerically simulate aerodynamics of rotor-airframe interaction in a rigorous manner, we need to solve the Navier-Stokes system for a rotor-airframe combination as a whole. This often imposes a serious computational burden since rotating blades and a stationary body have to be simultaneously dealt with. An efficient alternative is to adopt a momentum source method in which the action of rotor is approximated as momentum source over a rotor disc plane in a stationary computational domain. This makes the simulation much simpler. For unsteady simulation, the instantaneous momentum sources are assigned only to a portion of disk plane corresponding to blade passage. The momentum source is obtained by using blade element theory with dynamic inflow model. Computations are carried out for the simple rotor-airframe model (the Georgia Tech model) and the results of the simulation are compared with those of the full Navier-Stokes simulation with moving mesh system for rotor and with experimental data. It is shown that the present simulation yields results as good as those of the full Navier-Stokes simulation.

Effect of Lift-offset Rotor Hub Vibratory Load Components on Airframe Vibration Responses of High-Speed Compound Unmanned Rotorcrafts (고속비행 복합형 무인 회전익기의 Lift-offset 로터 허브 진동 하중 성분과 기체 진동 응답의 상관 관계의 연구)

  • Kim, Ji-Su;Hong, Sung-Boo;Kwon, Young-Min;Park, Jae-Sang
    • Journal of the Korea Institute of Military Science and Technology
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    • v.24 no.3
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    • pp.255-263
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    • 2021
  • This paper investigates numerically the effect of rotor hub vibratory load components on the airframe vibration responses of high-speed compound unmanned rotorcraft (HCUR) using a lift-offset coaxial rotor, wings, and two propellers. The rotor hub vibratory loads are predicted using a rotorcraft comprehensive analysis code, CAMRAD II, and the airframe vibration responses are calculated by a finite element analysis software, MSC.NASTRAN. It is shown that the vibratory hub pitch moment of a lift-offset coaxial rotor is the most dominant component for both the longitudinal and vertical vibration responses at four specified locations of the airframe.

Jet Flow Interactions in the Practical Airframe Design

  • Hong, Seung-Kyu;Lee, Kwang-Seop
    • 한국전산유체공학회:학술대회논문집
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    • 2006.10a
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    • pp.20-21
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    • 2006
  • Three kinds of jet flows encountered in the practical airframe design phase are discussed in this paper. Firstly, the side jet effect on the cavity flow over the flat plate was investigated. Secondly, the aerodynamic modeling of side jet influence on body-tail configuration was presented. Computational study of the similarity parameters was done to minimize the wind tunnel test. Lastly, supersonic jet impingement on a flat plate surrounded by solid walls was simulated numerically for both axi-symmetric and three-dimensional calculations with moving body method.

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Flutter Analysis of Small Aircraft using Full Airframe Dynamic FE Model (전기체 동적 유한요소 모델을 이용한 소형항공기 플러터 해석)

  • Lee, Sang-Wook;Paek, Seung-Kil;Kim, Sung-Chan;Hwang, In-Hee
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.424-429
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    • 2008
  • Aircraft flutter analysis model consists of dynamic FE model and aerodynamic model. Dynamic FE model is composed of stiffness and mass model, and is used for the prediction of normal mode characteristics of the structure. Since aircraft flutter analysis is normally performed in the modal domain, dynamic FE model shall be constructed to describe the modal characteristics of the structure with sufficient accuracy. In this study, dynamic FE modeling method was described using full airframe FE model and structural and system weight data for aircraft flutter analysis. In addition, full airframe dynamic FE model for composite small aircraft was constituted for normal mode and flutter analysis, and the mass modeling results were compared with the target weight data to validate the mass modeling method proposed. Finally, full airframe flutter analysis of composite small aircraft was performed with the dynamic FE model and the aerodynamic model composed.

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