• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.5
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• pp.359-366
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• 2017

In this paper, aerodynamic data of the Gaori kite was constructed through the wind tunnel experiment taking into consideration all the angles of attack formed during the flight of the Gaori kite. From this aerodynamic data, we made a morphing analysis of the relative length of the front bridle to the rear bridle required to achieve equilibrium flight as the angle of attack of the Gaori kite or the azimuth angle change. As a result, it was found that the relative length of the front bridle to the rear bridle depends entirely on the chord length of the kite, the relative wind speed and changes morphed according to the angle of attack. Using this information data, one can adjust the relative length of the bridle line to suit the kite attitudes and flight environments handling the kites that maintain optimal flight performance.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.1
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• pp.79-91
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• 2023

In response to the recent surge in aviation demand, major airports and aviation authorities continue to make efforts to formulate arrival and approach procedures that take into account efficient aircraft separation, noise and environmental issues of carbon (CO2) emissions. In order to ensure efficient traffic control and environmental issues, as a result, a new concept Trombone, Point Merge, etc. have been introduced and widely used in the domestic airspace. However, these new concept procedures which do not properly reflect the characteristics of the aircraft operation performance and the FMS vertical descent guidance hinder flight efficiency as well as bring in turn negative factors such as level-off flight and the use of drag device at the busiest phase of the flight descent operation, like the Continuous Descent Operation (CDO). Accordingly, throughout modification the current Standard Terminal Arrival Route (STAR) and Instrument Approach Procedure(IAP) that reflect the aircraft descent performance and the FMS guidance, the flight operation safety and efficiency is expected to be improved eventually. We herewith analyze and propose the way of improving flight efficiency in the arrival operation procedure by supplementary modification which consequently contribute to the aviation industry international competitiveness.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.51-59
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• 2024

Currently, the approved training organization (ATO) is being used worldwide to supply excellent pilots in the aviation industry. This system, which is used worldwide, has been transformed and utilized according to each country. In this study, the operation method and educational environment of specialized pilot training institutions in Korea were examined in detail, and the differences were compared by comparing the operation methods and flight education environments of international standards, the United States, Europe, Canada, and neighboring countries such as Japan, China, and Singapore to derive differences from the system of specialized educational institutions in Korea. Based on these comparative data, through a survey of workers in the relevant work, satisfaction with the number of department classes set by the domestic aviation safety law specialized educational institution designation standards differed greatly depending on the characteristics of the survey subjects, and the importance differed depending on the department's class subjects.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.746-754
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• 2023

Aircraft accidents are characterized by a low probability of survival compared to other means of transportation, and the main causes appear to be human factors such as violation of regulations and communication. In order to activate the safety management system to prevent such accidents, an important key variable is to recognize the importance of safety culture and actively engage in safety behavior rather than simply emphasizing compliance with regulations to flight crew members. Even if there are well-established regulations, safety culture, The effectiveness varies depending on the safety atmosphere and level of safety behavior. In this study, the correlation between safety culture and safety behavior was verified through a survey of domestic flight crew members' awareness of safety culture. The results showed that fair culture and self-reporting were not activated enough to have a significant impact on safety behavior. We aim to improve the performance of the safety management system by confirming the characteristics of safety culture and safety behavior.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.8-16
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• 2009

An experimental study was carried out to investigate aerodynamic characteristics on reduced frequency of flapping wings. The half span of the wing is 28cm, and the mean chord length of wing is 10cm. In flight, the Reynolds Number range of birds is about $10^4$, and the reduced frequency during a level flight is 0.25. The experimental variables of present study were set to have similar conditions with the bird flight's one. The freestream velocities in a wind tunnel were 2.50, 3.75 and $5.00^m/s$, and the corresponding Reynolds numbers were $1.7{\times}10^4$, $2.5{\times}10^4$ and $3.3{\times}10^4$, respectively. The wing beat frequencies of an experimental model were 2, 3 and 4Hz, and the corresponding reduced frequency was decided between 0.1 and 0.5. Aerodynamic forces of an experimental flapping model were measured by using 2 axis load-cell. Inertial forces measured in a vacuum chamber were removed from measuring forces in the wind tunnel in order to acquire pure aerodynamic forces. Hall sensors and laser trigger were used to make sure the exact position of wings during the flapping motion. Results show that the ratio of downstroke in a wing beat cycle is increased as a wing beat frequency increases. The instantaneous lift coefficient is the maximum value at the end of downstroke of flapping wing model. It is found that a critical reduced frequency with large lift coefficient is existed near k=0.25.

• Advances in aircraft and spacecraft science
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• v.6 no.1
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• pp.31-49
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• 2019

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarter-chord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of a helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter forward speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.9-17
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• 2006

The SNU MAV has been designed through studies on highly efficient aerodynamic shape and propulsion system. The configuration of the vehicle was determined from conventional empirical equations, iterative wind tunnel tests and flight tests. The propeller shape was optimized with the various thrust tests and RSM(Response Surface Method) to obtain the higher efficient propulsion system. It was certified that the MAV could fly for over 17 minutes with a 210mAh battery. In addition, it showed good flight characteristics in both stability and controllability.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.1 s.94
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• pp.63-71
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• 2005

In this study, structural vibration analyses of a composite smart unmanned aerial vehicle (UAV) have been conducted considering dynamic hub-loads of tilt-rotor. Practical computational structural dynamics technique based on the finite element method is applied using MSC/NASTRAN. The present smart UAV(TR-S2) structural model is constructed as full 3D configurations with both the helicopter flight mode and the airplane flight mode. Modal based transient response and frequency response analyses are used to efficiently investigate vibration characteristics of structure and installed electronic equipments. It is typically shown that the helicopter flight mode with the 90-deg tilting angle is the most critical case for the induced vibration of installed electronic equipments in the front.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.85-94
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• 2009

The Fly-By-Wire system was first applied to the fighter and its inherent advantages lead to the advent of the Fly-By-Wire civil aircraft. Recently even the small jet aircraft shows the trend of adopting the Fly-By-Wire system. In the future, most of the aircraft are expected to be the Fly-By-Wire type. In this paper, the structure and the characteristics of the Fly-By-Wire system applied to the civil aircraft was described. The development trend of the redundant method of the flight control system, data communication system, control surface actuation system and the control laws implemented by the Fly-By-Wire system of the civil aircraft are discussed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.1
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• pp.66-73
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• 2011

According to U.S. NTSB, from 1989 to 1992, Situation Awareness(SA) was a major factor causing 80% of all aircraft accidents in scheduled airlines. Therefore, the prevention of accidents through effective training in SA became a pivot in aviation safety. Furthermore, during the past 10 years, since all helicopter accidents in Korea were caused by the factors related to SA, an appropriate countermeasure has been required. This study, which uses survey data, examines various factors related to SA that could affect helicopter pilots. Common characteristics of situation awareness factors are that the result from the independent variables which are flight time, duty period and age of a first officer is statistically significant with the result from the independent variables of an instructor pilot's. However, only experience is statistically significant independent variable for factors influencing decision making in emergency situations, but anxiety, expectation and comprehension are not significant.