• 한국항공운항학회지
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• 제24권2호
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• pp.19-24
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• 2016

Positional stability analysis based on aerodynamic forces and induced moments of formation flight using two small aircraft models is presented. The aerodynamic force and moments of the trailing aircraft are analyzed in the aspect of flight stability. The induced moments with the change of local flow direction by wing-tip vortex from the leading aircraft can affect the flight positional stability of aircraft in closed formation flight. Aerodynamic forces and moments of trailing aircraft model are measured by 6-component internal balance at the 49 locations with vertical and lateral space between two aircraft models. Results are shown that the positional stability of trailing aircraft in formation flight can be analyzed by positional stability derivatives with vertical and lateral space. It is concluded that flying positions can be important factors for aircraft position stability due to induced aerodynamic force and moments with vertical and lateral spacing by the variation of flow pattern from the leading aircraft in formation flight.

• 한국항공운항학회지
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• 제15권4호
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• pp.142-147
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• 2007

When the aircraft is developed, several flight tests are performed including stability and controllability, performance and systems, above all the most important part of the flight test is stability test. Stability test is divided into two parts, static stability and dynamic stability. Static stability of the aircraft is typically defined in terms of its initial tendency to return to equilibrium after a disturbance and not included time concept. One of static stability, longitudinal static stability, was addressed here. The longitudinal static stability was studied from the basic theory to the flight test method and also explained data reduction method throughout the flight test. Finally showed how to meet the specifications such as ROC, FAR and MIL-specifications.

• 한국항공우주학회지
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• 제33권5호
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• pp.57-64
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• 2005

현대의 고성능 전투기에 탑재되어 있는 전기식 비행제어계통(Digital Fly-By-Wire Flight Control System)은 통합 다기능 감지기(IMFP : Integrated Multi-Function Probe)에 의해 항공기의 고도/속도/받음각 정보를 얻는다. T-50에 적용되어 있는 3개의 IMFP는 3중 결함 및 분리되지 않는 2중 결함에 대해서 비행 안정성(Flight Stability)을 확보하기 위해 형상 재구성 모드(Air Data Reconfiguration Mode)를 제어법칙에 적용했다. 본 논문에서는 항공기 운용 시 발생할 수 있는 IMFP 결함으로 인한 형상 재구성 모드 제어법칙에 대해, 비행 안정성을 해석하기 위하여 선형해석(Linear Analysis) 및 HQS( Handling Quality Simulator) 조종사 시뮬레이션을 수행하였고, T-50 비행시험 시, 발생했던 IMFP 결함으로 인해 제어법칙이 형상 재구성 모드로 적용되었던 사례를 제시했다. 그 결과, T-50 훈련기의 제어법칙이 형상 재구성 모드로 전환될 경우, 항공기 안정성에는 영향이 없다는 것을 알았다.

• 한국군사과학기술학회지
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• 제23권4호
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• pp.355-362
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• 2020

EFP composed of explosive, charge and liner generally penetrates standoff a target by Monroe effect. Its performance highly depends on penetrator characteristics and flight stability. Penetration ability can be dramatically reduced when the penetrator reaches the target with AOA, even if the penetrator has high kinetic energy and L/D ratio. Therefore, it is important to research not only penetrator characteristics and but also flight stability. In this work, the effect of liner shape on penetrator characteristics was examined using free flight test and numerical tools. It was found that tip velocity of penetrator was increased with decreasing liner thickness. It was also found that thicker liner had higher static margin leading to better flight status.

• International Journal of Aeronautical and Space Sciences
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• 제16권3호
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• pp.425-436
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• 2015

This paper presents the procedures used for estimating the stability and control derivatives of a general aviation canard aircraft from flight data. The maximum likelihood estimation method which accounts for both process and measurement noise was used for the flight data analysis of a four seat canard aircraft, the Firefly. Without relying on the parameter estimation method, several aerodynamic derivatives were obtained by analyzing the steady state flight data. A wind tunnel test, a flight test of a 1/4 scaled remotely controlled model aircraft, and the prediction of aerodynamic coefficients using the USAF Stability and Control Digital Data Compendium (DATCOM), Advanced Aircraft Analysis (AAA), and Computer Fluid Dynamics (CFD) were performed during the development phase of the Firefly and the results were compared with flight determined derivatives of a full scaled flight prototype. A correlation between the results from each method could be used for the design of the canard aircraft as well as for building the aerodynamic database.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1663-1666
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• 1997

The purpose of this paper is to find how to determine the controllability and stability derivatives form flight test and to display the stability of the Twinbee aircraft. There are various methods developed to find the derivatives : wind tunnel testing, predicted result from empirical data, flight test and so on. Among those methods, the estimation form flight test of real aricraft is the most reliable. We performed the flight test of Twinbee and recorded the states of aorcraft. Using those states and parameter setimation algorithem based on the Maximum Likdlihood(MMLE) criterion, we can estimate the controllability and stability derivatives. In this paper, wel will show the process form designing the proper flight test input to estimation of derivatives.

• 제어로봇시스템학회논문지
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• 제11권11호
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• pp.913-919
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• 2005

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modem version supersonic jet fighter aircraft. The flight control system utilizes RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. Standard CLDA (Control Law Design and Analysis) process is provided that reduce the development period of the flight control system. In addition, if this process is employed in developing flight control laws, it reduces the trial and error development and verification of control laws. This paper details the design process of developing a flight control law for the RSS aircraft, utilizing military specifications, linear and nonlinea, analysis using XMATH and ATLAS(Aircraft, Tim Linear and Simulation), handling quality tests using the HQS (Handling Quality Simulator), and real flight test results to verify aircraft dynamic flight responses.

• 제어로봇시스템학회논문지
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• 제11권11호
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• pp.963-969
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• 2005

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modem version supersonic jet fighter aircraft. The flight control system utilizes RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. The T-50 advanced trainer employs the RSS concept in order to improve the aerodynamic performance and the flight control law in order to guarantee aircraft stability, The T-50 longitudinal control laws employ the dynamic inversion and proportional-plus-integral control method. This paper details the design process of developing longitudinal control laws for the RSS aircraft, utilizing the requirement of MIL-F-8785C. In addition, This paper addresses the analysis of aircraft characteristics such as damping, natural frequency, gain and phase margin about state variables for longitudinal inner loop feedback design.

• International Journal of Aeronautical and Space Sciences
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• 제13권3호
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• pp.267-281
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• 2012

This paper reviews the flight mechanics and control of birds and bird-size aircraft. It is intended to fill a niche in the current survey literature which focuses primarily on the aerodynamics, flight dynamics and control of insect scale flight. We review the flight mechanics from first principles and summarize some recent results on the stability and control of birds and bird-scale aircraft. Birds spend a considerable portion of their flight in the gliding (i.e., non-flapping) phase. Therefore, we also review the stability and control of gliding flight, and particularly those aspects which are derived from the unique control features of birds.

• 한국항공우주학회지
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• 제34권3호
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• pp.93-100
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• 2006

현대의 고성능 전투기에 탑재되어 있는 전기식 비행제어계통(Digital Fly-By-Wire Flight Control System)은 항공기 조종면의 고장으로 인해 발생할 수 있는 항공기의 안정성을 보장하기 위해 조종면 형상 재구성 모드(Control Surface Reconfiguration Mode)가 설계되어 있다. T-50 제어법칙에는 단일 조종면이 고장 났을 경우, 정상작동중인 나머지 조종면을 이용하여 항공기를 원활히 조종할 수 있도록 형상 재구성 모드가 적용되어 있다. 본 논문에서는 항공기 운용 시 발생할 수 있는 조종면 결함으로 인해 형상 재구성 모드 제어법칙이 적용되었을 경우, 착륙외장형상에서 항공기 안정성을 해석하기 위하여 선형해석(Linear Analysis)을 수행하였다 그리고 착륙에 대한 비행성(Flying Quality) 저하여부를 판단하기 위해, HQS(Handling Quality Simulator)를 이용하여 조종사 시뮬레이션을 수행하였다. 해석결과, 조종면 고장으로 인해 제어법칙이 형상 재구성 모드로 전환될 경우, 항공기의 조종성 및 비행성의 저하가 다소 발생하였지만, HQS 조종사 시뮬레이션 결과 착륙과정에서는 비행성 요구도인 Level 1을 만족할 수 있었다.