• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.1-9
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• 2013

In order to increase endurance flight efficiency of long endurance electric powered UAV with solar cell, the light weight airframe design techniques are important. In this paper, the design of the main wing of electric powered UAV manufactured using Mylar film and fiber reinforced composite was conducted in order to achieve weight reduction and structural integrity of the structure. The shape of spar and size were determined using beam theory analysis. The finite element analysis of the wing was performed under various load condition derived from flight environment of EAV-2H. Finally, the static strength test of the main wing was conducted to verify structural integrity. It was found that the developed main wing weigh less than 42% than the previous EAV-2 and the main wing passed static strength test under ultimate load.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.623-626
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• 2015

본 연구에서는 CFD 해석 프로그램 EDISON_CFD를 통하여 2차 세계 대전에 소련에서 제작한 복엽기 AN-2의 기체를 기본 모델로 하여 설제 기체에 사용된 TSAGI P-II-14 airfoil를 이용, 기본 모델의 상단 주익과 미익은 고정하고 하단 주 날개의 위치를 변화시켜 공력특성을 분석하였다. 익형의 평행배치의 경우 기본모델에 비해 양력은 적은 크기로 증가하나 항력이 급격히 증가하여 가장 양항비가 낮은 비효율적인 공력 해석 결과를 보였고 복염기 하단 주익의 돌출은 상단 주익의 돌출에 비해 미세한 양력 감소와 항력 증가를 보여 양항비가 감소하는 현상을 보였다. 상, 하단 주익의 상하 간격이 커질수록 양력은 중가, 항력은 감소하며 간격이 작아질수록 양력의 감소와 항력의 증가를 보였다. 본 연구 해석 결과에 따라 순항조건에서의 익형은 상,하 주익간 수직 간격을 넓게 배치하는 것이 가장 효율적으로 볼 수 있다.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.178-184
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• 2012

In this study, implementation process of sensor-embedded main wing model for structural health monitoring is described. Fiber Bragg Grating (FBG) Sensor, Plumbum-Zirconate-Titanate (PZT) Sensor, and strain gauge are installed in the main wing of Jabiru UL airplane as a test-bed of Health and Usage Monitoring System (HUMS).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.4-4
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• 1998

이 연구에서는 100인승 항공기 급의 저익-주익장착나셀(wing mounted nacelle)의 추진기관 장착설계 방법을 제시하였다. 장착설계 방법을 구체적으로 설명하기 위해 세부적인 설계제한조건(design constraint)과 설계요구조건(design requirement and objectives)을 정의하고, 그러나 기준을 근거로 실례의 항공기(K100)를 사용하여 주익장착방식의 장착설계를 수행하였다. 장착설계는 간접항력(interference drag), roll clearance, ground clearance, nose gear collapse margin, rotor burst, 연료탱크용량 등의 설계제한 사항들을 고려하여 엔진성능을 만족시킬 수 있는 최적의 나셀 장착위치(spanwise, FS, WL)와 장착각도(toe-in, incidence, droop angle), wing day의 위치와 크기를 결정하여 향후에 개발될 주익장착방식의 추진기관 장착설계에 활용될 수 있는 설계절차를 구축하였다.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.316-320
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• 2013

본 논문은 일반 항공기와 카나드를 장착한 항공기의 차이점을 알아보기 위해 카나드와 주익의 수평위치에 따른 공력특성을 비교하였다. 카나드를 장착한 비행기는 비행 안정성에 이점을 얻을 수 있고 주익(Main wing)에서의 실속 현상을 미연에 방지 할 수 있는 장점이 있다. 이러한 현상을 알아보기 위해 카나드와 주익간의 위치를 변화시켜 그에 따른 공력특성을 EDISON 프로그램을 통해 해석하여 보았고 이를 ANSYS의 FLUENT를 이용하여 해석한 결과와 비교분석하여 신뢰성을 확보 할 수 있었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.1
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• pp.88-94
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• 1998

Installation design methods and results of an aircraft engine on the wing-mounted-nacelle type aircraft has been presented in this paper. The design process starts from design requirements and constraints and covers some major aspects of the engine installation design such as wing-nacelle interference drag, roll clearance, ground clearance, nose gear collapse margin, rotor burst and fuel tank capacity. The method was applied to 100-seat class airplane(K100). Results of the design suggest optimum nacelle location and nacelle installation angle(toe-in, incidence, droop angle) which satisfies in stalled engine performance and size/location of wing dry day.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.129-136
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• 2017

This study aims to assess the damage tolerance of the wing structure of aged aircraft with long-term service through the fatigue crack growth analysis and tests. For the fatigue-critical locations (FCL) W2 and W4 in the wing structure, the fatigue stress spectrum was derived based on a previous study. Thereafter, a crack propagation analysis for the FCLs was conducted using the commercial software $NASGRO^{TM}$. The algorithm for the fatigue stress spectrum was verified. Fatigue crack growth tests were then performed for two types of specimens: Type #1 was extracted from the wing structure of aged aircraft, and Type #2 was made of the same material as the wing structure. By comparing the experimental results of these specimens, we assessed the damage tolerance of the wing structure of aged aircraft with service time.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.72-79
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• 2021

In this study, as part of the development of an autonomous flying personal aircraft, an equivalent model of the main wing assembly of an Optionally Piloted Personal Air Vehicle (OPPAV) was developed. Reliability of the developed equivalent model was verified by eigenvalue analysis. The main wing assembly consisted of a main wing, an inboard pod, and an outboard pod. First, for developing an equivalent model of each component, components to produce the equivalent model were divided into several sections. Nodes were then created on the axis of the equivalent model at both ends of each section. In addition, static analysis with unit force and unit moment was performed to calculate the deformation or the amount of rotation at the node to be used in the equivalent model. Equivalent axial, bending, and torsional stiffness of each section were calculated by applying the beam theory. Once the equivalent stiffness of each section was calculated, information of a mass and moment of inertia for each section was entered by creating a lumped mass in the center of each section. An equivalent model was developed using beam element. Finally, the reliability of the developed equivalent model was verified by comparison with results of mode analysis of the fine model.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.627-631
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• 2015

유동 교란에 의하여 균일유동이 아닌 자유류가 항공기 날개 표면을 지나면 공력 계수들이 균일 자유류 유동과는 달라진다. 예를 들어, 항공기들의 편대 비행에서 앞의 항공기가 생성한 후류가 뒷 항공기에 영향을 주고, 두 개의 주익을 가지는 Tandem Wing 항공기의 경우 첫 번째 주익에서 발생된 후류가 두 번째 주익의 공력에 영향을 미친다. 본 연구는 NACA0012 익형의 앞쪽에 또 다른 익형을 배치하여 앞 쪽의 익형에서 발생한 후류가 뒤의 익형에 미치는 영향을 익형 사이의 거리에 따라 분석하였다. 앞쪽의 익형에서 발생한 압력계수와 뒤쪽에서 발생한 압력계수의 비교를 통해 후류의 효과가 어떤 영향을 끼치는지 확인 하였고, 두 익형 사이의 거리가 2c일 때 후류의 영향이 거의 없음을 확인 하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.74-81
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• 2004

In this study preliminary structural design has been performed to develop an all composite wing box for experimental aircraft(classified in FAR Part 21). Considerations on composite materials and their manufacturing process were taken into account throughout the design phase. Aerodynamic loads were estimated by using Shrenk method(NACA TM No 948) and FAR Part 23 Appendix A. The structural layout has been determined to carry effectively the critical loads and to maximize the benefit of composite structure. Maximum strain failure allowable and first ply failure criteria were applied for the sizing of major structural members. Finally, the designed composite wing box structure is presented in the form of drawings, which include material specifications, stacking sequences and joint design.