• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.554-559
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• 2017

Recently, the global attention is focused on the development of the renewal aero-propulsion systems proved in the air pollution, the noise, the great operational cost, safety and risks. Especially, various study are conducting for the development of the advanced high power to weight ratio aircraft through the significant reduction of fuel consumption and upgrade of the propulsion efficiency, using the alternative propulsion system developments such as hydrogen and solar power system. The hybrid propulsion system can be the representative propulsion system which get the power sources by combining the merits of two or more power sources. In this study, the advancement trends, characteristics, design method which can be applied to the renewal future UAV development.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.65-70
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• 2010

A small unmanned aerial vehicle(UAV), which uses a propulsion system consisting of electric motor and battery, weighs less than 8 kg, capable of hand launch. Because it is easy to operate and able to transmit image information in real time, the use of small UAV has been increasing. However, very few analysis methods or analysis results on flight performance of the small UAV have been known so far. In this paper, the performance analysis methods of a small UAV, which is manufactured to study an electric powered UAV, are suggested and their results are achieved. Aerodynamic data of the vehicle are obtained by making use of gliding performance from actual flight test, and required thrust and required power by flight speed are predicted. In addition, the methods to predict range and endurance in case of using battery as power source are suggested and their results are achieved.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.226-230
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• 2010

In this paper, the performance of an electric powered small Unmanned Aerial Vehicle which has a battery and electric motor is analysed. Aerodynamic data is obtained through flight test and flight performance is predicted. As a result, we present the optimum flight speed for the maximum endurance and predict endurance and range according to the variation of flight speed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.1-7
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• 2015

In the present study, we conducted the research on the high efficiency propulsion system for the development of long-endurance UAV with an electric propulsion system. For the long endurance UAV, fair aerodynamic characteristics with the high efficiency of the propulsion system is required because the flight power and the duration time of the long-endurance UAV vary greatly depending on the efficiency of the propulsion system. Therefore, in this study, the tracking program which records the performance of motor, propeller was developed because of their wide variation in the efficiency depending on the using condition, and records from the existing flight test program were utilized to check the accuracy of the program we had developed. For the development of future long-endurance solar UAV, we confirmed the applied voltage of motor, the optimal rotation of propeller and the gear ratio of reduction gear in order to get the highest efficiency on the propulsion system at the optimal flying condition.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.32-39
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• 2021

Electric propulsion aircraft are being actively researched in the aviation field in recent years to solve environmental and noise problems caused by existing gas turbine engine. In particular, research on a thrust motor as a core component of an electric power propulsion system and an inverter for driving it is actively being conducted. In this paper, a motor with high specific power is selected to determine characteristics of aircraft that are sensitive to weight and volume. Power loss of the inverter is then simulated. In the simulation, the selected motor and power device were modeled using PSIM, a power electronics analysis tool. Inverter power loss according to switching frequency was then analyzed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.2
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• pp.140-147
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• 2017

This paper describes the design and implementation of previously developed PMU (Power Monitoring Unit) for LiPB (Lithium-ion Polymer Battery) that is electric propulsion used as unmanned aerial vehicle's power source. Improved PMU provides stable voltage and current to various sensors and elctric motors necessary during flight. Voltage and current monitoring function that is measured by improved PMU more precisely be enhanced and the monitoring channel and temperature sensor is added. To verify the improved performance of the equipment, it is integrated to electric propulsion system of unmanned aerial vehicle. PMU is calibrated through the ground test. And PMU's performance is checked through the flight test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.908-914
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• 2013

This study has developed a small solar powered UAV and performed its flight tests. In daylight, a solar powered UAV flies by using some of electricity generated from solar cells, and stores the remainder into battery. At night it flies by using electricity from battery. A solar powered UAV should have aerodynamically efficient configurations, light-weight, strong wing and fuselage. Its electric propulsion system and solar power system should also be very efficient. In the present study the solar powered UAV and its solar power system are developed for 12 hour continuous flight and the flight tests are performed to verify its performance. The flight tests performed in fall and winter to prove the present solar powered UAV is successful in four-season 12 hour flight.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.12
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• pp.1097-1107
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• 2015

General VTOL aircraft uses gas turbine engine which has high power to weight ratio. However, in the VTOL UAV in small sector, the gas turbine as a prime mover is not adequate because of the limitation of the high fuel consumption ratio of the gas turbine. In this research, The Series Hybrid-Electric Propulsion System(SHEPS) has been proposed and technology survey & comparison analysis has conducted to constitute propulsion system for engine, electric motor and battery. To achieve this object a 65kg-class P-UAV from "Company I" was used. And to estimate the validity of power control algorithm and developed power management control, Matlab/simulink$^{(R)}$ has been used for the simulation. As a result, the developed algorithm worked comparatively well and the research has predicted that SHEPS was satisfied enough for 7 hour of endurance for mission profile.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.499-508
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• 2016

This paper describes a study of performance prediction of an electric propulsion system for multirotor UAVs. The electric propulsion system consists of motors, propellers, batteries and speed controllers, and significantly affects performance characteristics of the platform. The performance of the electric propulsion system for multirotor UAVs was predicted using an analytical model derived from the characteristics of each component, operation experiments and statistical analyses. Ground performance tests and endurance flights were performed to verify the reliability of the proposed performance prediction method. A quadrotor platform was designed to demonstrate the parcel delivery service used in the endurance flight. From the result of verification tests, it was confirmed that the proposed method has a good agreement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.47-58
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• 2014

In this research, the initial sizing of a HALE(High Altitude Long Endurance) UAV which uses solar power and hydrogen fuel cell as an alternative energy was performed. Instead of a wing box type, a glider type was chosen since it is relatively easy to get a data thanks to many researches abroad. Maximum takeoff weight is around 150Kg and the propulsion system is composed of motor, propeller, solar cell, and hydrogen fuel cell which can be recharged through electrolysis. Maximum takeoff weight was estimated as aspect ratio, wing span, wing area change while considering energy balance of required energy which is necessary for flight during the entire day and available energy which can be taken from the solar cell.