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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Aeronautical & Space Sciences
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Journal DOI :
The Korean Society for Aeronautical & Space Sciences
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Volume & Issues
Volume 41, Issue 12 - Dec 2013
Volume 41, Issue 11 - Nov 2013
Volume 41, Issue 10 - Oct 2013
Volume 41, Issue 9 - Sep 2013
Volume 41, Issue 8 - Aug 2013
Volume 41, Issue 7 - Jul 2013
Volume 41, Issue 6 - Jun 2013
Volume 41, Issue 5 - May 2013
Volume 41, Issue 4 - Apr 2013
Volume 41, Issue 3 - Mar 2013
Volume 41, Issue 2 - Feb 2013
Volume 41, Issue 1 - Jan 2013
Selecting the target year
A Numerical Investigation of the Main Rotor Tip-vortex and Counter-rotating Vortex during Hovering Flight
Jun, Jonghyuk ; Chung, In Jae ; Lee, Duck Joo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 761~769
DOI : 10.5139/JKSAS.2013.41.10.761
Effects of helicopter wakes on helicopter aerodynamics are serious, but the wake configuration is very complicated and hard to predict. The purpose of this study is the detailed observation of wake using numerical methods. Vortex lattice method and freewake method are used to track the vortices in the wake. In this paper, the wake configuration is observed during hovering flight. In the case of hovering flight at the moderate thrust level, besides tip vortex, counter-rotating vortex can be observed at the inboard part of blade. When the vortices move downward, tip vortex and counter-rotating vortex get close and influence to each other. Therefore, vortices are highly distorted due to their own instability.
A Study on Orbit Transfer Methods for Solar Sail Spacecraft
Kim, Min-Gyu ; Kim, Jeongrae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 770~778
DOI : 10.5139/JKSAS.2013.41.10.770
Solar sail propulsion uses solar radiation pressure to propel spacecraft without propellant, and it is useful for deep-space missions and continuos orbit maneuver missions. After a brief introduction of solar sail dynamics, locally optimal trajectories in Sun-centered and Earth-centered orbits are analyzed. Numerical simulations for the optimal trajectories are performed. Trajectory for the rendezvous with Halley comet is generated, and different planet escape methods are compared.
Computational Investigation of the Effect of UAV Engine Nozzle Configuration on Infrared Signature
Kang, Dong-Woo ; Kim, June-Young ; Myong, Rho-Shin ; Kim, Won-Cheol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 779~787
DOI : 10.5139/JKSAS.2013.41.10.779
The effects of various nozzle configurations on infrared signature are investigated for the purpose of analysing the infrared signature level of aircraft propulsion system. A virtual subsonic aircraft is selected and then a circular convergent nozzle, which meets the mission requirements, is designed. Convergent nozzles of different configurations are designed with different geometric profiles. Using a compressible Navier-Stokes-Fourier CFD code, an analysis of thermal flow field and nozzle surface temperature distribution is conducted. From the information of plume flow field and nozzle surface temperature distribution, IR signature of plume and nozzle surface is calculated through the narrow-band model and the RadThermIR code. Finally, qualitative information for IR signature reduction is obtained through the analysis of the effects of various nozzle configurations on IR signature.
Performance Evaluation of Magnesium Bipolar Plate in Lightweight PEM Fuel Cell Stack for UAV
Park, To-Soon ; Oh, Ji-Hyun ; Ryu, Tae-Kyu ; Kwon, Se-Jin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 788~795
DOI : 10.5139/JKSAS.2013.41.10.788
A magnesium bipolar plate whose surface was protected by thinly deposited silver layer was investigated as an alternative to existing graphite bipolar plate of PEM fuel cells. Thin silver layer of
was deposited on a magnesium alloy substrate by physical vapor deposition (PVD) method in an environment of
. A number of tests were conducted on the fabricated magnesium based bipolar plates to determine their suitability for use in PEM fuel cell stacks. The test on corrosion resistance in the same pH condition as in a PEM operation demonstrated the layer protected the magnesium alloy substrate, while unprotected substrate suffered from severe corrosion. The contact resistance of the fabricated bipolar plate was less than
which was superior to the conventional bipolar plates. A single cell was constructed using the fabricated bipolar plates and power output was measured. Due to the enhanced conductivity caused by low contact resistance, slight increase was observed in current density and output voltage. With low density of the magnesium substrate and ease on machining, the weight reduction of the stack of 30~40 % is possible to produce the same power output.
Design, Analysis and Experiment of Potato Gun with a Spherical Projectile
Kang, Hong-Jae ; Kim, Ji-Hwan ; Kim, Young-Sik ; Son, So-Eun ; Choi, Han-Ul ; Choi, Jeong-Yeol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 796~804
DOI : 10.5139/JKSAS.2013.41.10.796
The "Potato Gun," a simple heat engine, is fabricated, tested and analyzed as a part of engineering education program of combustion and propulsion classes. Combustor pressure is predicted by the chemical equilibrium analysis of a constant volume combustor. Then, the internal ballistics, the conversion of thermal energy into the mechanical energy of a projectile, is predicted though the expansion process. The trajectory of a projectile is estimated by considering the aerodynamic effect around the spherical projectile. The energy conversion efficiency and the equivalence ratio of the fuel-air mixture could be estimated by the comparison of the experimental results and the theoretical prediction. The present work would be an example of attracting the interest of students for the application of the engineering principles at undergraduate level by recycling the waste materials.
Development of Operational Flight Program for Smart UAV
Park, Bum-Jin ; Kang, Young-Shin ; Yoo, Chang-Sun ; Cho, Am ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 805~812
DOI : 10.5139/JKSAS.2013.41.10.805
The operational flight program(OFP) which has the functions of I/O processing with avionics, flight control logic calculation, fault diagnosis and redundancy mode is embedded in the flight control computer of Smart UAV. The OFP was developed in the environment of PowerPC 755 processor and VxWorks 5.5 real-time operating system. The OFP consists of memory access module, device I/O signal processing module and flight control logic module, and each module was designed to hierarchical structure. Memory access and signal processing modules were verified from bench test, and flight control logic module was verified from hardware-in-the-loop simulation(HILS) test, ground integration test, tethered test and flight test. This paper describes development environment, software structure, verification and management method of the OFP.
Development of a Test System for a Hemispherical Resonator and Control of Vibrating Pattern
Kim, Dongguk ; Yoon, Hyungjoo ; Jin, Jaehyun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 813~819
DOI : 10.5139/JKSAS.2013.41.10.813
The authors have developed a test system for a hemispherical resonator gyroscope by using NI FPGA equipment. We have verified its suitability for the research of resonator gyroscopes through several tests: deriving resonance, controlling amplitudes, and estimating resonator parameters. The authors have adjusted a vibrating pattern to be aligned with the driving axis (or electromagnets). This pattern alignment is a basic and important operation of the FTR mode, which is one of operating modes for resonant gyroscopes.
An Aircraft CLAS Antenna Design using Composite Magneto-dielectric Material
Kim, Yo-Sik ; Bae, Ki-Hyoung ; Yu, Byung-Gil ; Kim, Min-Sung ; Park, Chan-Yik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 820~826
DOI : 10.5139/JKSAS.2013.41.10.820
In this paper, a compact and wideband CLAS(Conformal Load bearing Antenna Structure) was studied using smart skin technique. In order to satisfy the electrical performance of the CLAS antenna, the proposed CLAS antenna is composed of conductive mesh, face-sheet, radiator, honeycomb, housing. Especially, radiator is composed of composite magneto-dielectric material and radiating element etched on the PCB (Printed Circuit Board). The radiating element is inserted into the composite magneto-dielectric material and has sloted Folded LP(Log Periodic) structure. By fabricated composite magneto-dielectric, the resonance frequency is decreased and the impedance matching characteristics is improved. We verified that the antenna has wideband characteristics and compact size using the antenna test results.
Performance Verification of Separation Nut Type Non-explosive Separation Device for Cube Satellite Application
Oh, Hyun-Ung ; Lee, Myeong-Jae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 827~832
DOI : 10.5139/JKSAS.2013.41.10.827
Heating wire cutting type separation mechanism has been widely used for cube satellite applications due to its design constraints such as small size of
and light weight of less than 1kg. In addition, usage of pyro technic device is not allowed for cube satellite application. The conventional methods have some disadvantages of relatively small mechanical constraint force and the system complexity for the multi-deployable systems. In this paper, a separation nut type non-explosive separation mechanism has been proposed and investigated. The effectiveness of the design has been verified through the qualification tests of the mechanism.
Design and Performance Test of a Cryogenic Blower for Space Thermal Environment Simulation
Seo, Heejun ; Ahn, Sungmin ; Huh, Hwanil ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 833~839
DOI : 10.5139/JKSAS.2013.41.10.833
Thermal vacuum test should be performed prior to launch to verify satellites' functionality in a harsh space environment which is represented by extremely cold temperatures and vacuum conditions. A thermal vacuum chamber which consists of a vacuum vessel, a pumping system, and a thermal control system are used to perform thermal vacuum tests of a satellite system and its components. A cryogenic blower is a core component of the closed loop thermal control system for thermal vacuum chambers. This paper describes the fan design of the cryogenic blower, the design of the thermal protection interface between the driving part and the fluid part, which were verified by thermal and structural analyses. The performance of the cryogenic blower is confirmed by similarity test on the test bench.
Target Level of Safety Analysis in Airworthiness Certification for Military UAV
Lee, Narae ; Jeon, Byung-Il ; Chang, Young-Keun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 41, issue 10, 2013, Pages 840~848
DOI : 10.5139/JKSAS.2013.41.10.840
Airworthiness certification of military aircraft is a government's certification that it must have airworthiness and ability to demonstrate its requested function and performance. NATO released STANAG-4671 to establish the minimum airworthiness requirements for UAVs between 150kg and 20,000kg MTOW in 2009. Up to now, there are no clear airworthiness certification criteria and guideline for small UAV which is less than 150kg. STANAG-4671 is used for military UAV airworthiness certification in Korea as Other Airworthiness Certification Criteria. However, since STANAG-4671 requires the same Target Level of Safety without regard to MTOW, excessive Target Level of Safety or design requirements could be applied to relatively small-medium UAV. In this paper, classification and criteria of airworthiness certification for military UAV were investigated and a Target Level of Safety was analyzed based on MTOW using ground victim criteria.