• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.487-498
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• 2022

This study aims to determine the importance of each factor considered when operating a rotorcraft in a city. After identifying factors that could affect urban air mobility, we reviewed the influencing factors by applying an analytic hierarchy process (AHP). Level 1 classifies the essential factors of the urban operation of rotorcraft in nominal and off-nominal situations. The factors corresponding to the characteristics of each were composed of lower levels, such as Levels 2 and 3. Using this, the importance of influencing factors was analyzed and the most important factors were determined. The most influential factors of the urban operation of rotorcraft included engine failure, fire situations, and vehicle safety. Accordingly, an environment that can guarantee safe operation by considering the most influential factors in advance in an actual operation stage must be constructed.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.133-143
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• 2023

This paper describes the system integration laboratory's requirement analysis, implementation, and verification for multiple-scenario unmanned aerial vehicle operation and control technology using a manned rotorcraft for Manned-Unmanned Teaming. System integration laboratory consists of manned rotorcraft flight simulation, unmanned aerial vehicle flight and mission equipment simulation, ground control system simulation for unmanned aerial vehicle control and change in the control authority between the ground control system and manned rotorcraft, and operation and control system for mission plan's writing and transmission. Each implemented simulation verified the requirements through software and hardware integration test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.713-721
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• 2014

In Europe and USA, new programs called GRC(Green Rotorcraft) and SRW (Subsonic Rotary Wing program) respectively, have been currently underway for developing the next generation rotorcraft. The final goal is to develope fuel-efficient/environmental-friendly tilt-rotor civilian rotorcraft, which can partly replace short-range regional aircrafts. Also for safe operation, the new rotorcraft technology is cooperated with the new air transport management(ATM) system, called SESAR(Single European Sky ATM Research) and NextGen(Next Generation Air Transport System) in Europe and USA. In addition to achieve the final goal, the tilt-rotor aircraft, they are trying to improve the performance of conventional helicopters by adopting more efficient propulsion system, active rotor system, and reducing internal and external noise. Especially in GRC program of Europe, the environmental factors such as noise, fuel efficiency, reduction of emission gas(CO2, NOx), are focused for the new technologies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.736-741
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• 2017

This paper examines the design for improving the wiper system of rotorcraft. During rotorcraft operation, the wiping performance and excessive clearance can decrease. The wiper system consists of a wiper arm assembly, motor, convertor and flex drive. If there is a problem with the wiper system, the operation ability decreases because the operation is restricted in a rainy environment. There are two main causes of the problem of the wiper system: the lifting forces acting on the wiper arm in aircraft flight and the excessive gap of the components. To remedy these two problems, the wiper arm was improved. The improvements included increased contact pressure on the wiper arm (spring tension), improved gear clearance, and material and shape changes. Durability test, aircraft ground test and flight test were carried out to verify the improved shape, and it was confirmed that the wiping performance and clearance problems were solved. Currently, the rotorcraft is operated without problem by applying the improved shape, and this design improvement process will be a useful reference for future rotorcraft development.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.140-147
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• 2009

The paper presents the design, development and testing activities of the multi-rotorcraft-based unmanned aerial vehicle at the Center for Unmanned System Studies, Institut Teknologi Bandung (ITB), Indonesia. The multi-rotor system was selected as the design stepping stone for future development of personal aerial vehicle prototypes. A step-by-step design program is conducted to study the technology building blocks and critical issues associated with the design, development and operation of personal aerial vehicles. A number of multi-rotor configurations have been investigated providing basic guidelines for developing a stable unmanned aerial platform. The benefit of the presently selected configuration is highlighted and some preliminary testing results are presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.458-465
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• 2011

UAV-UGV teaming concept has been proposed that can compensate for weak points of each platform by providing carrying, launching, recovery and recharging capability for the VTOL-UAV through the host UGV. The teaming concept can expand the observation envelop of the UGV and extend the operational capability of the UAV through mechanical combination of each system. The spherical-shaped coaxial rotorcraft UAV is suggested to provide flexible and precise interface between two systems. Hybrid navigation solution that included vision-based target tracking method for precision landing is investigated and its experimental study is performed. Feasibility study on length-variable rotor to provide the compact configuration of the loaded rotorcraft platform is also described.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.774-780
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• 2021

The auxiliary power unit (APU) of a rotorcraft starts the engine during operation/flying. The APU is composed of a gas turbine engine type. The starting principle of the component is that the electric start motor generates the power required for starting by rotating the shaft. In this study, quality improvement was performed by applying an over-running clutch (ORC) between the APU and the starter motor to secure the operability of the starter motor of the APU mounted on the rotorcraft. The starter motor has the main role of starting the APU, but during operation, it is rotated without load by the rotational force of the APU gear shaft, resulting in friction at the brush. This phenomenon causes abrasion of the brush of the starter motor. Consequently, when the APU operation time increases, the brush life decreases, and the operability of the APU is affected. In this study, an ORC that separates the interlocking between the start motor brush abrasion and the APU operation time was applied to improve the operability/durability of the APU starter motor. The effect was verified through a test, and the technical feasibility of the design change was analyzed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.10
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• pp.667-676
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• 2015

Working displacement variation by elastic deformation of active Gurney flap which was operated on high frequency was observed. Flap-wise natural frequency was lower than mode analysis result and hinge boundary condition was identified to be the cause through the simple modal test. Design modification for increasing natural frequency was conducted for minimizing the elastic deformation at maximum 35 Hz operating condition which was design requirement condition. Brass bushing was applied instead of rotating bearing for gap minimization and Gurney flap design modification was conducted to increase of the flap-wise natural frequency. Design modification effect was validated by natural frequency comparison with mode analysis result and modal test result of design modification model.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.798-803
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• 2013

In this paper, the activities of North America to enhance the flight safety of helicopter were introduced. In North America, by 2009, 49% of worldwide civil helicopters are in operation. The development trends of North America to enhance the flight safety of helicopter are expected to have a significant impact to the other helicopter operating areas. The analysis of the case of Gulf of Mexico where large fleet of Helicopter in operations, FAA's NextGen program, and the Canadian plan to comply with the ICAO's Aviation System Block Upgrades plan shows the direction of helicopter avionic development for enhancing the flight safety of helicopter.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.6
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• pp.83-90
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• 2017

Performance analysis of the turboshaft engines for combined rotorcraft was executed. A tip jet and a ducted fan aircraft were selected for combined rotorcraft application. Gasturb 12 software was used for turboshaft engine performance analysis. In the results, maximum required power for the tip jet engine is about 1,600 hp class and maximum required power for the ducted fan engine is about 1,000 hp class at the required aircraft mission. This is due to the additional power of the auxiliary compressor to get a bleed air mass flow rate for the tip jet operation. At the same time, fuel consumption of the tip jet aircraft is 2.8 times larger than ducted fan case. Therefore ducted fan type aircraft is more efficient than tip jet aircraft in terms of fuel economy.