• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.4
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• pp.469-477
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• 2015

In this study, the characteristics of main wind direction, vertical temperature and wind speed profile near the Moseulpo airfield for HALE UAV(High Altitude Long Endurance Unmaned Aerial Vehicle) is investigated. The results are summarized as follows, main wind direction is governed by air mass according to season and local wind such as land-sea breeze. The directions of landing and take-off of HALE UAV will be selected as the south-east direction in June ~ August, north-west direction in October ~ March, and south-east direction at daytime in April ~ May, September. Annual variation of temperature at 100 hPa showed that temperature in summer season is lower than winter season. On the other hands, wind speed at 250 hPa in winter season is higher than summer season. The threshold values of temperature and wind speed for HALE UAV flight are $-75^{\circ}C$ and $90ms^{-1}$, which were determined by 5 % frequency value($1.96{\sigma}$), respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.433-440
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• 2022

High Altitude Long Endurance(HALE) solar powered UAV is the vehicle that flies for a long time as solar power energy sources. It can be used to replace satellites or provide continuous service because it can perform long-term missions at high altitudes. Due to the property of the mission, it is very important for HALE solar powered UAV to have maximum flight time. It is required for mission performance to fly at high altitudes continuously except a return for temporary maintenance. Therefore mission availability time analysis is a critical factor in the commercialization of HALE solar powered UAV. In this paper, we presented an analytic model and logic for available time analysis based on the design parameters of HALE solar powered UAV. This model can be used to analyze the possibility of applying UAV according to the UAV's mission in concept design before the UAV detail design stage.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.1
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• pp.50-55
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• 2011

In this study, simultaneous aero-structural design was performed for HALE aircraft wing. The span and the shape of main spar were considered as design variables. To maximize aerodynamic performance and to minimize weight, multi-objective optimization was used. Nonlinear static aeroelastic analysis was performed to compute large deflection of wing. Design of experiment and response surface method were used to reduce computation cost in the design process. Also, aerodynamic performances of deformed wing and rigid wing were compared.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.77-84
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• 2015

Recently, as the needs for eco-friendly aero propulsion system increase gradually, many study works have been conducted to develop the hybrid propulsion system for High Altitude Long Endurance(HALE) UAV. In this study, we analyzed both suitable energy distribution and management methodology among the total energy collected from solar cell and the total required energy of aerial vehicle and required energy of the regenerative fuel cell(RFC) for driving in the night time and optimized the energy balance mechanism based on the ascribed mission profile.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.4
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• pp.1-8
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• 2019

Recently, development of long endurance electric powered airplane has been conducted worldwidely. Light structural weight of a main wing with sufficient structural integrity is essential for long endurance flight. Since a main wing with a slender spar can occur catastrophic fracture under the flight, it is important to establish a design and verification method for both the weight reduction and structural integrity. In this paper, structural design and analysis of the main wing of HALE UAV with tubular spar reinforced with a bulkhead were introduced. The static strength test of the main wing was performed to verify structural integrity under the static load. Then, the experimental result was compared with an analytical result from a finite element analysis. It was concluded that the developed light weight main wing would have sufficient structural integrity under the flight operation.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.101-107
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• 2019

This study conducted a simulation to observe the performance of a multi-turbocharged gasoline internal combustion engine for a high-altitude long-endurance unmanned aerial vehicle (HALE UAV). The WAVE 1-D engine simulation software from Ricardo was used for the engine system modeling and simulation. The specifications of a 2.4-L four cylinder gasoline engine from commercial vehicles and maps of commercial vehicle turbochargers were applied to the multi-stage turbocharged engine system model. Three turbochargers and intercoolers were installed in series for the appropriate intake of pressure for the gasoline engine at a high altitude of 60,000 ft. There was one wastegate for the turbochargers. The operability of the engine system was analyzed via this simulation model.

• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.199-210
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• 2000

We present the results from narrow-band spectrophotometry of Comet Hale-Bopp (C/1995 O1) near perihelion obtained at Sobaeksan Optical Astronomy Observatory 61cm telescope equipped with PM 512 CCD camera(512$\times$512, 0.5"/pixel) and narrow-band filter set for the comet on 19 nights from February 21 to May 1, 1997. We discuss molecular emission band morphology and photometric behavior of Comet Hale-Bopp. The morphology of CN band shows more symmetric light distributions than $C_2$ or $C_3$ bands. On other hand, $C_2$ and $C_3$ band have more compact light distributions than CN band. Similar to wide-band image, molecular band morphology shows spiral structures at the core of the comet. The CN surface brightness variation with changing heliocentric distance shows difference from those of $C_2$ and $C_3$. The brightness, however, of these molecular bands near perihelion shows previously known 7day period light variations.

• Bulletin of the Korean Space Science Society
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• 1997.04a
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• pp.7.2-7
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• 1997

• Bulletin of the Korean Space Science Society
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• 1997.04a
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• pp.12.2-12
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• 1997

• Bulletin of the Korean Space Science Society
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• 1997.04a
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• pp.13.2-13
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• 1997