• Title/Summary/Keyword: aircraft wing

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Numerical Investigation of The Effect of External Stores on Tail Wing Surfaces of a Generic Fighter Aircraft (전투기 형상의 외부장착물이 꼬리날개에 미치는 영향에 대한 수치적 연구)

  • Kim, Min-Jae;Kwon, Oh-Joon;Kim, Ji-Hong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.3
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    • pp.211-219
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    • 2008
  • A three-dimensional inviscid flow solver has been developed based on unstructured meshes for the investigation of the effect of the external stores on the tail surfaces of a generic fighter aircraft. The numerical method is based on a vertex-centered finite-volume discretization and an implicit point Gauss-Seidel time integration. The calculations were made for a steady flow and the computed results were compared with experimental data to validate the flow solver. An unsteady time-accurate computation of the generic fighter aircraft with external stores at transonic flight conditions showed that the external stores cause unsteady loading on the horizontal tail surface due to the mutual interference between their wake and the horizontal tail surface. It was shown that downward deflection of the trailing edge flap significantly reduces the undesirable interference effect.

Modal Test and Finite Element Model Update of Aircraft with High Aspect Ratio Wings (고세장비 항공기의 모드 시험 및 동특성 유한요소모델 개선)

  • Kim, Sang-Yong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.5
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    • pp.480-488
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    • 2012
  • The aircrafts with high aspect ratio wings made by a composite material have been developed, which enable high energy efficiency and long-term flight by reducing air resistance and structural weight. However, they have difficulties in securing the aeroelastic stability such as the flutter because of their long and flexible wings. The flutter is unstable self-excited-vibration caused by interaction between the structural dynamics and the aerodynamics. It should be verified analytically prior to first flight test that the flutter does not happen in the range of flight mission. Normally, the finite element model is used for the flutter analysis. So it is important to construct the finite element model representing dynamic characteristics similar to those of a real aircraft. Accordingly, in this research, to acquire dynamic characteristics experimentally the modal test of the aircraft with high aspect ratio composite wings was conducted. And then the modal parameters from the finite element analysis(FEA) were compared with those from the modal test. To make analysis results closer to test results, the finite element model was updated by means of the sensitivity analysis on variables and the optimization. Finally, it was proved that the updated finite element model is reliable as compared with the results of the modal test.

Initial Climb Mission Analysis of a Solar HALE UAV (태양광 고고도 장기체공 무인기의 초기 상승 임무 분석)

  • Shin, Kyo-Sic;Hwang, Ho-Yon;Ahn, Jon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.6
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    • pp.468-477
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    • 2014
  • In this research, how a solar powered HALE (high altitude long endurance) UAV (Unmanned Aerial Vehicle) can climb and reach mission altitude, 18km, starting from the ground using only solar energy. A glider type aircraft was assumed as a baseline configuration which has wing area of $35.98m^2$ and aspect ratio of 25. Configuration parameters, lift and drag coefficients were calculated using OpenVSP and XFLR5 that are NASA open source programs, and climb flights were predicted through energy balance between available energy from solar power and energy necessary for a climb flight. Minimum time climb flight was obtained by minimizing flight velocities at each altitude and total time and total energy consumption to reach the mission altitude were predicted for different take off time. Also, aircraft moving distances due to westerly wind and flight speed were calculated.

DVI cable Improvement for Preventing MFD Abnormal Display of a Rotary-wing Aircraft (회전익 항공기 다기능시현기의 이상시현을 방지하기 위한 DVI 케이블 개선)

  • Kim, Young Mok;Jeong, Sang-Gyu;Cho, Jae Po;Choi, Doo-Hyun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.9
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    • pp.782-789
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    • 2018
  • Multi-Function Display (MFD) of Korean Utility Helicopter (KUH) displays image information(navigation, flight, topographical and maintenance information) delivered from Mission Computer (MC) during flight operation. The abnormal display of MFD such as flickering phenomenon was identified in the system development. It was solved by improving the shielding performance of the DVI cable and changing the DVI cable installation path at the first mass production. However, it was occurred again when the aircraft was operated for one or two years after delivery. It was also identified in the evaluation process of the derivative helicopters. Therefore, a comprehensive review of the aircraft system level has been performed to solve the problem of MFD malfunction at first and then a design improvement plan was derived by improving the DVI cable. In this paper, the causes of MFD anomalies are analyzed and also the process of design improvement are summarized. The validity of the improvement has been verified through the DVI cable assembly comparison test, SIL/ground/flight test.

A Study on Mission Software Reliability Test Methods of International Joint Development Project for KT-1 Military Aircraft Software (KT-1 군항공기 소프트웨어 국제공동개발 사업의 미션 소프트웨어 신뢰성 시험방안에 관한 연구)

  • Byung Duck Bae;Seonah Lee
    • Journal of Aerospace System Engineering
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    • v.17 no.6
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    • pp.108-117
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    • 2023
  • Thus far, a mission software component of the KT-1 military fixed-wing aircraft for overseas export has been developed through international joint development with foreign companies. The reliability of the software component could be certified by complying with the development environment and procedures of foreign companies based on DO-178B. However, recently, DO-178C certification is required for overseas exports, and reliability tests to comply with the weapon system software development guidelines are required for domestic military forces. In this paper, we describe the problems in obtaining domestic airworthiness certification in the international joint development of a previously developed KT-1 export-typed aircraft system integration project. To this end, we find a solution to comply with both DO-178C and the Weapon System Software Development and Management Manual and provide the optimal software reliability test method.

A Study on Aeroelastic Characteristic using Two-dimensional Full Aircraft (전기체 2차원 모델을 이용한 공력탄성학적 특성에 관한 연구)

  • Bong-Do Pyeon;Jae-Sung Bae
    • Journal of Aerospace System Engineering
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    • v.18 no.4
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    • pp.10-17
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    • 2024
  • Solar-powered unmanned aerial vehicles(SPUAV), which are being actively developed domestically and internationally, generally feature high aspect ratio(AR) wings. These high AR wings necessitate a lightweight design as their weight increases, rendering them susceptible to flutter. Consequently, flutter analysis is critical from the initial design phase. Typically, flutter analysis is conducted using a standard section wing or more precisely through a 3D model. However, due to the extended analysis time required by 3D models, this study opts for a 2D aircraft model. The 2D model computes faster than the 3D model and intuitively secures the flutter boundary. In this study, a structural/aerodynamic force model of the 2D aircraft was established, and the findings were compared with those from a 3D half model. The results showed that the flutter analysis between the 2D model and the 3D half model was similar, within about a 3% margin, thus validating the proposed 2D model's effectiveness.

Optimum Placement and Shape of UHF Monopole Antenna Mounted on UAV (무인항공기에 장착된 UHF 모노폴 안테나의 최적 위치 및 형상)

  • Choi, Jaewon;Kim, Jihoon;Chung, Eulho
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.9
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    • pp.46-51
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    • 2013
  • In this paper, the optimum placement and shape of UHF antenna on the unmanned aerial vehicle (UAV) are analyzed by using the electromagnetic (EM) simulation on the various locations. The FEKO was used for the EM-simulation. In order to reduce the complexity of simulation and minimize the runtime and memory usage, the composite aircraft structure is simplified as the PEC model excluding the radome structure. The simulation was performed on the wing and ventral fin of UAV, and the antenna shape used the monopole, dipole, and bent monopole antennas. When the monopole antenna is mounted under the wing, two antennas need to be mounted under the right and left wings, and those antennas have to be switched as the direction of UAV wing to the line of sight (LOS) data-link (DL) ground antenna. In the case of mounting under the ventral fin, one antenna can be used regardless of the direction of UAV wing to the LOS DL ground antenna. Also, the antenna gain is improved by the blockage reduction. The antenna gain is further improved by using the bent monopole antenna. The optimum solution of UHF antenna placement and shape on UAV is to mount the bent monopole antenna under the ventral fin.

STRUCTURAL DEFORMATION EFFECT ON THE AERODYNAMICS OF A WING WITH WINGLETS (Winglet이 부착된 날개의 구조변형에 의한 공력 변화)

  • Lee, Y.M.;Kang, Y.J.;Jung, S.K.;Myong, R.S.;Cho, T.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.39-42
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    • 2009
  • The aerodynamic characteristics of aircraft winglet with structural deformation was investigated using the static FSI(Fluid-Structure Interaction) system. The system, comprised of CAD, CFD, CSD, VSI, and grid regeneration modules, was constructed. In the process VSI, grid regeneration, and integration modules were developed to combine CSD and CFD modules. As a test model, KC-135A, the double winglet suggested by Whitcomb, was selected and its aerodynamic characteristics for the rigid and deformable models was calculated by applying the static FSI system. As a result, the lift and drag coefficients of test models were reduced to 11% and 1.3%, respectively.

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The study of self excited type brushless charging generator, it has generated region (발전영역을 갖은 자동형 brushless 충전발전기에 관한 연구)

  • Byung In Oh
    • 전기의세계
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    • v.18 no.4
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    • pp.7-15
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    • 1969
  • In this method the condenser excite winding has the phase angle of 90 electrical degree, with the load winding in stator. The condenser excite wing is connected with the condenser while the load winding is with the full rectifer. Direct and quardrature axis components of rotating field winding are composed, of balanced two phase winding, and each one of them is connected with half wave rectifiers. Initically, small amount of lead current can be induced at the condenser excite winding by residual magnetism of rotor. The induced lead current forces the rotating field winding to be excited by synchronous alternating magnetic field. The speed electromotive force, there for, induced in rotating field winding shall electro magnetize the rotating field pole by rotating half wave rectifiers. In the case of the charging generator directly coupled with engines at the operation of wide range speed, the generated region, such as vehicles, aircraft, ships etc, is occured. In conclusion, we can take the advantage of, omitting of voltage regurator and current limiter for charging load and reducing the consumption of fuel using the generated region which can be devided in to Impossible generated region, Generated region, and suspension generated region.

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A Study on Aptitude for Helicopter Pilots through the Job Analysis (직무분석을 통한 회전익 항공기 조종사 적성에 관한 연구)

  • Yu, T.J.;Kim, C.Y.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.14 no.1
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    • pp.63-69
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    • 2006
  • The operational environment of helicopters extends from the civil air traffic control system to remote and hazardous areas and from day operations under visual flight conditions to night operations in adverse weather. Helicopters can move in any direction, remain stationary while airborne, climb and descend vertically, and take off and land almost anywhere. Thus their range of maneuvers and control requirements vary more widely than do those of fixed-wing aircraft. In this study, I analyzed the job of helicopter pilot through methods of observation, and classified the required ability of them into the domain of cognitive, perceptual/spatial, psychomotor. I expect that the result of this study will be used to aid training and selection of helicopter pilot.

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