• 한국항행학회논문지
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• 제23권4호
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• pp.281-288
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• 2019

비행시험은 항공기 개발 및 인증을 비롯한 항공기 수명 주기에서 감항성 유지를 위해 반드시 수행해야 하는 중요한 절차로서 관련 표준에 대한 적합성을 입증 또는 검증하기 위한 것이다. 비행시험 항공사고 분석 결과는 항공기 자체 요소뿐만 아니라 다양한 복합 원인에 의해 발생되었음을 확인한다. 국제민간항공기구는 항공기 사고 방지를 위해 안전관리시스템 구축 및 이행을 권고하고 있으나 비행시험의 특수성은 반영되어 있지 않다. 이에 항공선진국들은 이해관계자의 비행시험 안전관리 수행을 지원하기 위해 별도의 기준을 제공하고 있다. 본 논문에서는 국내 국가종합비행성능시험장 구축에 맞춰 항공선진국의 관련 규정을 조사, 분석하고 조직 구성, 안전 및 리스크 관리, 비행 운영, 인력 관리, 행정 사항 등의 내용을 포함하는 비행시험 운영 매뉴얼 개발을 위한 정부차원의 기준 안을 제시한다.

• 한국항행학회논문지
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• 제28권1호
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• pp.60-67
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• 2024

민간항공사고의 대부분은 인적요인에 의해 발생하고 특히 회전익 항공기는 예상하지 못하거나 의도하지 않게 악기상으로 진입하는 IIMC (instrument meteorological conditions) 상황에서의 사고가 많이 발생하고 있다. 이 연구는 저시정 조건에서 회전익 항공기 조종사의 에러율를 다각적으로 분석하여 비행특성에 관한 통찰력을 얻고 IIMC 상황에서의 사고를 줄이기 위한 방안을 연구하였다. 저시정 조건에서 조종사의 에러 발생율을 모션이 장착된 비행 시뮬레이터를 활용하였으며 65명의 조종사가 실험에 참여하였다. 실험을 통해 획득한 비행 데이터로 비행시정 감소, 공간정위상실 유무, 조종사 자격 등 다양한 조건에 따라 에러 발생율을 비교 분석하였다. 분석결과 다양한 조건에서 비행특성에 대한 특이점을 발견할 수 있었고 조종사의 자격 등급, 계기비행 (IFR; instrument flight rules) 자격 유무, 비행단계별 에러 발생율에 유의미한 차이가 발생하였다. 이와 같은 연구의 결과는 조종사의 교육 및 훈련프로그램을 개선하고 IIMC 상황에서 항공기 사고예방에 중요한 기여를 할 것으로 기대된다.

• International Journal of Aeronautical and Space Sciences
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• 제12권2호
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• pp.190-199
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• 2011

Unsteady flow simulations of complete helicopter configurations were conducted, and the flow fields and the aerodynamic interferences between the main rotor, fuselage, and tail rotor were investigated. For these simulations, a three-dimensional flow solver based on unstructured meshes was used, coupled with an overset mesh technique to handle relative motion among those components. To validate the flow solver, calculations were made for a UH-60A complete helicopter configuration at high-speed and low-speed forward flight conditions, and the unsteady airloads on the main rotor blade were compared to available flight test data and other calculated results. The results showed that the fuselage changed the rotor inflow distribution in the main rotor blade airloads. Such unsteady vibratory airloads were produced on the fuselage, which were nearly in-phase with the blade passage over the fuselage. The flow solver was then applied to the simulation of a generic complete helicopter configuration at various flight conditions, and the results were compared with those of the CAMRAD-II comprehensive analysis code. It was found that the main rotor blades strongly interact with a pair of disk-vortices at the outer edge of the rotor disk plane, which leads to high pulse airloads on the blade, and these airloads behave differently depending on the specific flight condition.

• International Journal of Aeronautical and Space Sciences
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• 제15권2호
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• pp.212-217
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• 2014

Micro Aerial Vehicles (MAVs) are useful devices to assess new features that may be utilized in a full size aircraft to enhance performance or to increase endurance. In this article, sources for energy saving in the micro air vehicles are initially addressed. Then, by specifying the important parameters on energy consumption of an aircraft, a feasibility study is conducted to assess the benefit of using solar cells to increase flight endurance. Next, a new solar cell has been designed and optimized for MAVs. This cell consists of a multiple quantum wells for which the quantum factor and the absorption coefficient are calculated by solving the Shrodinger equation using MATLAB software. Then, the manner and influence of MAVs parameters using the solar cells are examined to suggest optimal planform for different purposes. In order to increase flight endurance, it is noted that by using appropriate planform and the optimized solar cells, flight endurance can be increased by more than 30 percent.

• International Journal of Aeronautical and Space Sciences
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• 제11권4호
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• pp.285-302
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• 2010

Active aeroelastic control is an emerging technology aimed at providing solutions to structural systems that under the action of aerodynamic loads are prone to instability and catastrophic failures, and to oscillations that can yield structural failure by fatigue. The purpose of the aeroelastic control among others is to alleviate and even suppress the vibrations appearing in the flight vehicle subcritical flight regimes, to expand its flight envelope by increasing the flutter speed, and to enhance the post-flutter behavior usually characterized by the presence of limit cycle oscillations. Recently adaptive and robust control strategies have demonstrated their superiority to classical feedback strategies. This review paper discusses the latest development on the topic by the authors. First, the available control techniques with focus on adaptive control schemes are reviewed, then the attention is focused on the advanced single-input and multi-input multi-output adaptive feedback control strategies developed for lifting surfaces operating at subsonic and supersonic flight speeds. A number of concepts involving various adaptive control methodologies, as well as results obtained with such controls are presented. Emphasis is placed on theoretical and numerical results obtained with the various control strategies.

• Advances in aircraft and spacecraft science
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• 제8권4호
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• pp.289-302
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• 2021

Ensuring flight safety for passengers as well as crew is the most important aspect of modern aviation, and in order to achieve this, it is necessary to be able to forecast the durability of individual components. The present contribution illustrates the results of a computational analysis to determine the possibility of analysing the prediction of bearing durability in on-board rotating equipment from the point of view of thermal fatigue.In this study, a method developed at the Air Force Institute of Technology was used for analysis, which allowed to determine the bearing durability from the flight altitude profile. Two aircraft have been chosen for analysis - a military M-28 and a civilian Embraer. As a result of the analysis were obtained: the bearing durability in on-board rotating devices, average operation time between failures, as well as failure rate. In conclusion, the practical applicability of this approach is demonstrated by the fact that even with a limited number of flight parameters, it is possible to estimate bearing durability and increase flight safety by regular inspections.

• 한국환경과학회지
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• 제31권7호
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• pp.543-553
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• 2022

The latest aerospace technology is important for the stable flight of a launch vehicle, but weather conditions on the day of launch are also one of the essential factors for successful launch campaign. If a launch vehicle is directly struck while preparing to take off from the launch pad on the day of launch or the electronic device are damaged by induced current during flight of the launch vehicle, this means launch failure and can lead to enormous national loss. Therefore, for a successful launch campaign, it is necessary to analyze the lightning detection characteristics of the Naro Space Center. In this study, the seasonal factors of the lightning that occurred over the Naro Space Center from 2003 to 2017, the influence of the polarity, and the correlation with the lightning intensity was confirmed. As a result, there was a high probability of intensive occurrence of multiple lightning strikes in summer, and a high proportion of positive (+) lightning strikes in winter. Lastly, in the distribution of the number of lightning strikes, an average of 2.0 to 2.5 negative (-) lightning strikes occurs in the coastal regions of the South and West Seas when one flash happens.

• 한국군사과학기술학회지
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• 제12권2호
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• pp.248-257
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• 2009

The aim of this paper is to propose fighter aircraft's mission severity model which can be used as one of key factors for designing a structure and determining design life of KF-X. The mission severity is a quantitative data of flight loads and expressed by Nz(Vertical Load Factor) exceedances or occurrences. The severities of the flight loads depended on the circumstances of the countries which operate fighter aircraft. In this paper we have studied on Nz occurrences/exceedances of ROKAF fighter aircraft to generate mission severity model for the KF-X. The analyses of flight data were accomplished by using the Matlab.

• 한국군사과학기술학회지
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• 제11권3호
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• pp.30-39
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• 2008

An artificial vision aided NDGPS/INS system has been developed and tested in the dynamic environment of ground and flight vehicles to evaluate the overall system performance. The results show the significant advantages in position accuracy and situation awareness. Accuracy meets the CAT-I precision approach and landing using NDGPS/INS integration. Also we confirm the proposed system is effective enough to improve flight safety by using artificial vision. The system design, software algorithm, and flight test results are presented in details.

• 분석과학
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• 제8권4호
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• pp.715-722
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• 1995

The structural characterization for series of polyesters has been done by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Polymer fragments and intact oligomers composed of large numbers of repeat units have been investigated. Transesterification of polyesters in trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CFA) was monitored and reaction products were identified using TOF-SIMS. The shapes and intensities of clusters in transesterification spectra show good agreement with the theoretical isotope pattern. TOF-SIMS spectra were used to obtain information about the progress of the transesterification reaction.