• International Journal of Aeronautical and Space Sciences
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• v.14 no.2
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• pp.162-171
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• 2013

A general purpose aircraft mission performance analysis program has been developed. The program can be used in design mode or in analysis mode. Fuel weight for a given mission profile can be estimated when the design mode is chosen, while mission time or mission range for a given fuel can be estimated when the analysis mode is chosen. The mission analysis program is written with JAVA and includes GUI(Graphic User Interface) for users' conveniences. With a proper combination of databases for propulsion, aerodynamics and weight, the program can be configured to compute the performance of any type of aircraft. The program is validated by comparing its results with the results of a well known performance analysis program by ADD(Agency for Defense Development).

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.90-93
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• 2000

Al ally 7050 has been developed for higher strength and improved property against stress-corrosion cracking. Since the use of this alloy becomes more important for forged aircraft structural components. $\phi$ 65mm extruded billet has been forged for a highly-stressed aircraft parts. After forging processing and heat treatment, the forged parts showed undesirable microstructure caused by severe local grain coarsening at the surface layer and heavily-localized metal flow, the analysis of resulted in degraded mechanical properties. The above results have been compared to simulation by using the DEFORM-3D and those showed the thermomechamical processing must be optimized in terms of forging temperature, strain rate and deformation amount. To prevent the grain coarsening at the surface layer $\varepsilon$ heavily-localized grain flows.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.11
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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.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.453-457
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• 2011

In this study, transonic aeroelastic response analyses haw been conducted for the business jet aircraft configuration considering shockwave and flow separation effects. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to wing-body configurations. In transonic flight region, the characteristics of static and dynamic aeroelastic responses have been investigated for a typical wing-body configuration model. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.299-299
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• 2011

In this study, transonic aeroelastic response analyses have been conducted for the business jet aircraft configuration considering shockwave and flow separation effects. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to wing-body configurations. In transonic flight region, the characteristics of static and dynamic aeroelastic responses have been investigated for a typical wing-body configuration model. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.

• Journal of Aerospace System Engineering
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• v.3 no.1
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• pp.42-46
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• 2009

The 1st development of "Human Powered Aircraft(HPA)" in Korea has been conducting by KAFA(Korea Air Force Academy) from Aug. 2008 to now. HPA is an aircraft powered by directly human energy. The thrust provided by the human power may be the only source and that is weak. Therefore, light weight and strong structure is first requirement. In this paper, treating a basic conceptual design of HPA and material property and material choice for HPA. Also analysing the structure and checking the safety of HPA.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.48-54
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• 2009

We implemented the Aural Cueing System(ACS) system of the reconfigurable tactical trainer(RTT) for th rotor aircraft. RTT provides a collective training system to meet aviation training requirements and supports organizational training for aviations units in combined arms collective training and mission rehearsal. ACS handles the volume, pitch and repetition of the digitally stored sounds based on commands it receives from an UDP/IP. In this paper, we explained and implemented the conceptual and detail design the ACS system for the rotor aircraft such as AH-1H(Iroquios), UH-60(Blackhwak), AH-1(Cobra) etc. The conceptual design composed of the sound cueing data analysis, sound modelling which is inner, outer, weapon and warn environment of rotor aircraft, sound synthesis and replay.

• Journal of Aerospace System Engineering
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• v.4 no.3
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• pp.24-28
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• 2010

The purpose of this study is to define available microwave absorbing structure for aircraft from in the X-band(8.2~12.4GHz) frequencies. The electromagnetic wave absorption or shielding techniques is an important issue not only for military purpose but also for commercial purposes. Aircraft Radar Absorbing Structure(RAS) is absorbed or scattered propagation waves from the enemy radar. There are absorbing technologies at shaping design techniques and using Radar Absorbing Materials(RAM). RAM is more important because shaping design can't include perfect radar absorbing performance. In this study, based on material properties was introduced RAM and to analyze the each characteristics. Finally, we comparison appropriate RAM for aircraft.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.8
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• pp.649-656
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• 2013

High-lift devices have a major influence on takeoff, landing and stall performance of an aircraft. Therefore, a slotted flap design optimization process is proposed in this paper to obtain the most effective flap configuration from supported 2D flap configuration. Flap deflection, Gap and Overlap are considered as main contributors to flap lift increment. ANSYS Fluent 13.0.0$^{(R)}$ is used as aerodynamic analysis software that provides accurate solution at given flight conditions. Optimum configuration is obtained by Sequential Quadratic Programing (SQP) algorithm. Performance of the aircraft with optimized flap is estimated using Aircraft Design Synthesis Program (ADSP), the in-house performance analysis code. Obtained parameters such as takeoff, landing distance and stall speed met KAS-VLA airworthiness requirements.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.2
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• pp.114-121
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• 2019

Tailless aircraft have advantages of low visibility compared to conventional aircraft, but drawback of poor stability as well which makes designing controller difficult. The controller design is more difficult, especially when the center of gravity moves due to store release or fuel consumption during flight. In this paper, an L1 adaptive controller is proposed as a way to overcome these problems. The reliability and performance of the controllers were verified by non-linear simulations. RPV Flying Quality Design criteria were used for design criteria. Using the simulation, it is shown that the adaptive controller maintains stability of the unmanned aircraft for sudden large change in the inertial properties. It is also shown that the calculation burden can be reduced when it is used with the gain scheduling method.