• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.88-93
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• 2003

This Paper described the simulation program development for helicopter. In the design of flight control system to accomplish some special missions like UAV, it is important to minimize the execution time obtaining a linear model from nonlinear model that is used for design of controller. The first step for this kind of purpose is to complete a nonlinear model that contains full dynamic characteristics. The second step is to get the trim values that are obtained from the nonlinear model by solving an algebraic equation. And then stability and control derivatives are derived through hovering to forward flight by numerical perturbation that will be used for linear model for a specified flight condition. The software program(HeliSim) is developed by using MATLAB GUI and will provide easy modeling procedure. The suggested method in this paper is much more simpler than any other method like a fully scale helicopter model. The advantage of our suggested method will reduce the computational time due to simple formula to extract a linear model from nonlinear model that will be beneficially used for flight control system of unmanned helicopter by some reduction of computational load.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.4
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• pp.406-412
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• 2009

Flight simulation model for helicopter simulator is one of the most important models which affect flight performance and handling quality. It is typical to develop the model based on the raw data and models from the helicopter designers/manufacturers. The approaches in this study were to develop the basic model based on the available resources regarding helicopter operation/maintenance and to tune and validate it based on the flight test results. The basic model was developed with maintenance manuals, flight manuals, analyses, measurements, papers and so on considering that KA-32T data could not be obtained from the manufacturer. The flight test for KA-32T was performed and the reference data for the simulation validation tests were acquired. The flight simulation model was validated to have the fidelity compatible with level C of FAA AC120-63 after comparison and tuning with flight test results.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.83-91
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• 2009

This paper concerns the dynamic property of TVC system in the upper stage of KSLV-I. The minimum bandwidth of TVC system is predicted by gathering and comparing the dynamic test data through whole development phases of KSLV-I. The linear models which approximate the dynamic data are also suggested. It is shown that the minimum bandwidth of KSLV-I TVC system is guaranteed over 6.0 Hz at one degree command. It is also shown that the linear model of KSLV-I TVC dynamics takes the form of the transfer function with an 8-th order denominator and a 2-nd order numerator. These results will play an important role in analyzing the flight stability and performance of KSLV-I.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.76-82
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• 2003

To guarantee the proper functions of a satellite in the extreme space environment, the several test models are developed generally. There are advantages that the design and the analysis of Flight Model(FM) can be validated through these test models, and the functional reliabilities can be increased by reflecting the modifications on the final design of FM. The integration and test of Structure & Thermal Model(STM) of KOMPSAT, being currently developed, have been completed. In this paper, the processes of design and analysis of the STM propulsion system, one of the KOMPSAT modules, are described.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.179.2-179.2
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• 2012

과학기술위성 3호는 우리 은하계의 근적외선 관측, 우주 배경복사 관측 및 지구 지표면의 적외선 영상 획득을 임무로 하는 우주관측용 적외선카메라와 지구 지표면의 적외선 영상획득을 임무로 하는 지구관측용 적외선카메라 그리고 한반도 지역의 다중 스펙트럼 영상을 획득함으로써 대기관측 및 환경감시의 임무를 가지는 소형분광영상카메라를 장착한 우주 및 지구과학 연구용 위성이다. 2007년 개발을 시작하여 시험인증모델(EQM, Engineering& Qualification Model) 개발과 열구조모델 (STM, Structure and Thermal Model)을 개발 완료하였고, 2012년 하반기에 발사를 앞두고 2010년 비행모델 유닛들이 납품되기 시작하여 위성체 시스템 레벨에서의 조립 및 시험을 진행하고 있다. 본 논문에서는 조립 및 기능시험 중 발견된 유닛의 문제들을 해결 과정과 시스템 레벨에서의 전기접합시험, 극성시험, 비행소프트웨어 기능시험, 종합기능시험 및 ETE 시험등 기능 시험의 종류, 목적 그리고 검증 결과를 발표하고자 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.3
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• pp.243-250
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• 2012

In this paper, a systematic consequence of evaluation method, procedure, and flight data analysis is investigated for application of ADS-33E-PRF to UAV. And it is applied to unmanned rotorcraft for evaluation. CNUHELI-020, which is developed in Chungnam National University, is used for assessment of handling quality: decoupled longitudinal and lateral/directional model were used to assess handling qualities. Evaluation flight maneuvers are categorized as hover/low-speed requirements, small-amplitude attitude change, and moderate-amplitude attitude change requirements.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.5
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• pp.63-73
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• 2022

Investigation on operation of the test apparatus for the M4 semi-freejet tests with a full-scale vehicle model was carried out utilizing domestic facilities. An integrated design of the experimental apparatus and the vehicle model was obtained through iterative computational fluid dynamics (CFD) analysis. The test results showed that the M4 nozzle of the apparatus was fully expanded to provide required test conditions. It was also found that the intake of the vehicle model successfully started, and the corresponding shadowgraph images were recorded during the test. A variable nozzle of the model was set to adjust the back pressure of the model combustor, and wall-static pressures were measured to obtain the pressure distribution at the main locations of the model. The flame of torch ignitors and pilot fuel ignition were observed in a flame-holder of the combustor.

• Composites Research
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• v.14 no.2
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• pp.50-59
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• 2001

The predictions of residual strength evolution and fatigue life of full scale composite rotor blade for multipurpose helicopter were studied using a strength degradation model. Flight-by-flight load spectrum was developed on the basis of FELIX standard spectrum data. The laminated structural analysis was also performed to obtain corresponding local stress and/or strain spectra for each ply of laminate skin and glass roving spar structures around the blade root where fatigue damage was severely anticipated.

• Journal of Advanced Navigation Technology
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• v.22 no.3
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• pp.189-197
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• 2018

In Korea, most of the land area is composed of mountainous areas, making it difficult to develop airports because there is not enough open space to operate airports or airfields. However, the current development of the air transportation industry and the rapid increase of aviation demand, the construction of the training airfield infrastructure should be more actively reviewed for safe and smooth flight training. In this study, we analyze the actual condition of operation of domestic training airfield and the case study of overseas training site in order to establish appropriate level standard model of training infrastructures. In addition, this study suggests implications for the appropriate scale and operational efficiency of the training flight infrastructure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.167-171
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• 2012

A computational analysis of nozzle flow is conducted to investigate effects of the flight altitude on thrust performance. Reynolds-averaged Navier-Stokes equation with k-${\omega}$ SST(Shear Stress Transport) turbulence model is employed to simulate the nozzle flow in various altitude conditions, where continuum mechanics is to be valid. Thrust performance of the nozzle is exceedingly poor upto 10 km of flight altitude because of the irreversible phenomena such as shock and/or flow separation occurring inside the nozzle, whereas it is restored to the nominal value as the altitude is attained higher than 30 km.