• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.1 s.20
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• pp.49-55
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• 2005

Due to small and light mission payloads, subsystems and propulsion system, small sized UAVs come to be available for reconnaissance that have been performed by aircraft and huge UAVs. The objective of this study is to develop an efficient propulsion system for small reconnaissance UAVs. A glow engine was modified for an efficient and robust 4-stroke gasoline engine with carburetor, new electronic control unit and lubrication system. Engine modification technique and small engine performance test stand are capable of economical method for military UAVs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.475-478
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• 2006

본 논문에서는 소형 무인항공기의 정확한 위치, 속도, 자세 정보를 제공하기 위해 저급의 MEMS IMU를 이용한 항법 시스템을 제안한다. 제안하는 시스템은 비행체의 직선운동과 회전운동을 측정할 수 있는 관성측정기와 위성신호를 수신하여 항체의 위치, 속도 정보를 제공하는 GPS 수신기, 지구 자기장 정보를 이용하여 방향각 정보를 제공하는 지자기 센서들로 구성되었다. SDINS와 약결합 방식의 칼만필터를 이용한 항법 시스템은 초기정렬 알고리즘과 센서 오차 보상 알고리즘, 자력계 보상 알고리즘 및 복합항법 알고리즘으로 나뉘며, 설계된 항법 알고리즘들은 시뮬레이션과 차량 실험을 통해서 성능을 분석하였다.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.74-80
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• 2022

The utilisation of small drones is becoming increasingly widespread particularly in the military sector. In this study, STANAG 4586, a standard interface for military unmanned aerial vehicles, was applied to a multicopter-type small drone to examine the suitability of the military system. To accomplish this, a small multi-copter vehicle was designed and manufactured, integrating a flight control computer, ground control system, and data link. Furthermore, flight control and ground control equipment software were developed by applying the STANAG 4586 interface, followed by HILS and flight tests.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.1-7
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• 2006

This paper presents a new point navigation guidance law which is useful for unmanned helicopters. Predicting the future position, the guidance law generates velocity and heading commands, which are used as input to autopilot. This method differs from conventional guidance law in that it reorients the direction of flight velocity vector directly, not by bank angle indirectly. For flight tests, we have developed a flight control system for a R/C helicopters. The system consists of a flight control computer, navigation sensors, and a ground station The results of the test show that the proposed law guides a unmanned helicopter along a line path within a given area. In the future, we are planning to extend the guidance law to the mission of path following. i.e., waypoint navigation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.387-391
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• 2009

The experimental study on the ducted fan for the propulsion system of a small UAV has been performed. In this paper, to investigate the three-dimensional unsteady flow field characteristics of the ducted fan, it was measured by using a $45^{\circ}$ inclined hot-wire from hub to tip at inlet, behind the rotor and outlet of the ducted fan. The hot-wire signal data was acquired at fixed yaw angle. The data was averaged by using the PLEAT (Phase Locked Ensemble Averaging Technique), and then three of non-linear equations were solved simultaneously by using the Newton-Rhapson numerical method. Flow characteristics such as tip vortex, secondary flow and tip leakage flow were confirmed through axial, radial and tangential contour plot.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.1-6
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• 2014

Power system of the tilt-duct VTOL aerial robot has been developed. This paper focuses on the power train with small liquid-type engine for the R/C boat and presents the test results with design procedures. The hardware aspects of the power system include details about the hardware configurations for the interfaces with the vehicle. The ground test and tether test for measuring the thrust performance of vehicle and evaluating the endurance of power train carried out.

• Journal of Practical Engineering Education
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• v.8 no.1
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• pp.1-7
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• 2016

In this paper, the proceedings and core procedures that involved the role of advisor to the theme, the set up rule of students, and complete the work steps involved in configuring graduate work that the overall design curriculum and graduation standards are summarized. The one or two students are designated as one team, and by the designated professor was conducted a discussion and technical guidance. Among various topics from 2011 to 2015, some specific results configured using a small drone and smartphones are presented. The survey are compared the activity results for the participating students in one major each in 2011 and 2015 and analyzed. Based on this review for improvement next year notes, it forms a continuous improvement, and has converged talents with passion and challenging spirit, sharing a plan to form a virtuous cycle that is associated with positive employment and entrepreneurship.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.99-104
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• 2009

In this paper, the drop characteristic of the small aircraft landing gear of SUAV has been analyzed and performed on orifice optimal design for shock absorption efficiency. The SUAV landing gear was simple oleo pneumatic type without metering pin. The landing gear was modelled by MSC ADAMS software. Drop test evaluation was conducted to confirm the analysis model. As a result of correlation between analysis and test results, it was verified that these results were coincided with very well. After confidence review of analysis model through the correlation between test and analysis results, design parametric study was performed by using confirmed analysis model. Optimal orifice size with best efficiency have been decided in this study.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.10
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• pp.1031-1037
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• 2010

This paper proposed lightweight aluminum bipolar plates as an alternative for conventional graphite bipolar plates in fuel cell systems used as a power source for small reconnaissance UAVs. Since bipolar plates occupy more than 80% of the total weight of the fuel cell system, lightweight aluminum bipolar plates can improve the overall payload and flight time of the fuel cell UAV. The aluminum and graphite bipolar plates were fabricated to compare the performance of each of them. A 15% higher performance per weight was obtained from aluminum bipolar plates than the graphite bipolar plates. Also, the performance of a single cell using aluminum bipolar plates was evaluated under various operating conditions.

• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.10-16
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• 2017

In order to improve the safety of the multi-copter, Korea Aerospace Research Institute (KARI) performed a wind-tunnel test using an octocopter with the maximum takeoff weight (MTOW) of 28 kg. The wind-tunnel test was performed with three different RPM ranges, 3,500, 4,500 and 5,500 rpm, and three different wind speeds, 3.5, 5 and 7 m/sec. The tested range of the angle of attacks was $-40^{\circ}$ to $20^{\circ}degree$ and ${\pm}90^{\circ}degree$. Vortex ring state (VRS) of the tested multi-copter was located around the vertical descending speed of 6 m/sec and the decrement of thrust was about 13 % at the time of testing. Compared with the single propeller wind-tunnel test result, the propeller efficiency of the octocopter dropped to 10 to 15% depending on the propeller RPM. It is hypothesized that the obtained aerodynamic characteristics by the wind-tunnel test will be used to improve the performance and wind resistance of the multi-copter.