• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.273-284
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• 2012

In this paper, a study on the design of high speed airfoil is described. Various airfoils are investigated and existing airfoils are geometrically interpolated to generate new airfoils. An optimization method is applied to theses new airfoils and their aerodynamic performances are optimized. Through this study, it is demonstrated that the airfoil can be designed using the geometrical interpolation and the optimization method to exhibit good aerodynamic performances.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.498-511
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• 2017

This work conducts a validation study for loads analysis of the UH-60A slowed rotor at high advance ratios. The nonlinear flexible multibody dynamics analysis code, DYMORE II, is used with a freewake model for the rotorcraft comprehensive analysis. Wind tunnel test data of airloads and structural loads of a full-scale UH-60A slowed rotor are used for this validation study. This analysis predicts well the thrust reversal phenomenon at the advance ratio of 1.0. The section airloads such as normal forces and pitching moments and the oscillatory blade structural moments in this analysis are compared well or moderately with the measured data, although the higher harmonics components of blade torsion moments are not captured well. This validation study assesses the prediction accuracy and investigates the unique aeromechanics characteristics of a slowed rotor at high advance ratio.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.4
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• pp.147-153
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• 2020

This study analyzed the outlook for aviation demand for the recovery of the aviation industry, focusing on airlines facing difficulties in management due to the Covid-19 crisis. Although the timing of the recovery in aviation demand is uncertain at the moment, this study is based on prior research related to Covid-19 and forecasts by aviation specialists, and analyzed by SWOT technique to a group of aviation experts to derive and suggest implications for the prospects of aviation demand. Looking at the implications based on the analysis results, first, customer trust to prevent infection should be considered a top priority for recovering aviation demand. Second, promote reasonable air price policy. Finally, it seeks to try various research and analysis techniques to predict long-term aviation demand to overcome Covid-19.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.3
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• pp.257-268
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• 2018

We have studied the damage mechanism of a metallic thin plate by the highly energetic fragments generated from high explosive(HE) warhead. The penetration process has presumed that the velocity of a fragment is in the range of 350 m/s to 3353 m/s, the thickness of Aluminum 2024 target plate is in the range of 1 mm~6.3 mm thick. The mass of fragment with hemisphere nose shape is in the range of 0.32 g to 16 g. The analytical solution for penetration process has been derived by using the report of the project THOR. The results of analysis implied that the closed forms by an exponentially decay function well fit the change of the ballistic limit velocity, loss velocity and loss mass of fragment as the mass of fragment and the thickness of target plate increase.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.628-631
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• 2008

The information transfer between the ground facilities and the ground facilities and exchange are necessary for an aircraft and ground facilities so that it is safe, it is economic, an aircraft tan operate an aircraft to the high efficiency until it arrives at the destination location from the stand-by for the fly. Presently, by using the AFTN which is closed network, a communication is made. However, by applying the leading edge communication technology, the aeronautical telecommunication network of the next generation is constructed and it is planning to be managed. Due to this, the ground facilities connected to the foreign network has the security vulnerability by an attack. Therefore, the vulnerability analysis for the safe operational environment build-up at the aeronautical telecommunication network and sorority requirement research are needed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.7
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• pp.569-576
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• 2013

The Airworthiness Certification from the government has an increasingly important role due to the dramatic growth of military aircraft development industry. It is a mandatory process of qualifying the flight safety within the aircraft's operational boundaries throughout its life cycle. The introduction of airworthiness certification has resulted in development paradigm shift from one requirement for one consumer need to the common requirement for many needs. This research paper provide the refinement of airworthiness certification criteria related to the flight control law and the verification methods which comply with its criteria.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.8-14
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• 2005

Understanding of the flow past a bluff body close to a moving ground is very important in automobile and aeronautical fields because of aerodynamic characteristic and instability induced by unsteady vortex shedding. The passive control method that mounted the vertical and horizontal plates at the lower surface of the cylinder is studied to suppress the unsteady oscillation motion. When the grounds moves, the diminish of the shear layer on the ground promotes the interaction between the lower and the upper separated shear layers of the cylinder, hence vortex shedding occurs at the lower gap height than the stationary ground.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.642-647
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• 2009

We proposed the method of avionics integrated architecture using high-speed fiber optic bus. Typically, data bus of aircraft consists of electronic and optic data transmission method. Avionics systems are difficult to operate the electronic data transmission method for the high speed data processing, synchronization and interconnection between flight control system and flight management system efficiently. In this paper, it is known to look into the problem of data bus and the advanced trend in avionics systems, and propose the appropriate data bus of the advanced avionics systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.22-31
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• 1999

The conventional RZ-SSB demodulator consists of a limiter, FM demodulator and a linearizer. Since the conventional linearizer which cancels the high-order distortions must include Hilbert transformer, the performance of the demodulator are determined by the Hilbert transformer which is very complicated to realize in aeronautical telecommunication. This paper describes a method of designing RZ-SSB demodulator without Hilbert transformer. Since avionics systems are able to eliminate the inherent disadvantages in RZ-SSB, the results of this paper suggest that the RZ-SSB demodulator without Hilbert transformer is suitable for aeronautical telecommunication transceiver systems used in HF band.

• Steel and Composite Structures
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• v.17 no.2
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• pp.173-184
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• 2014

This study aimed to theoretical calculate the thermal residual stress in continuous SiC fiber reinforced titanium matrix composites. The analytical solution of residual stress field distribution was obtained by using coaxial cylinder model, and the numerical solution was obtained by using finite element model (FEM). Both of the above models were compared and the thermal residual stress was analyzed in the axial, hoop, radial direction. The results indicated that both the two models were feasible to theoretical calculate the thermal residual stress in continuous SiC fiber reinforced titanium matrix composites, because the deviations between the theoretical calculation results and the test results were less than 8%. In the titanium matrix composites, along with the increment of the SiC fiber volume fraction, the longitudinal property was improved, while the equivalent residual stress was not significantly changed, keeping the intensity around 600 MPa. There was a pronounced reduction of the radial residual stress in the titanium matrix composites when there was carbon coating on the surface of the SiC fiber, because carbon coating could effectively reduce the coefficient of thermal expansion mismatch between the fiber and the titanium matrix, meanwhile, the consumption of carbon coating could protect SiC fibers effectively, so as to ensure the high-performance of the composites. The support of design and optimization of composites was provided though theoretical calculation and analysis of residual stress.