• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.185-193
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• 2021

The system needs to be modified to improve the performance of the aircraft in operation or to satisfy the requirements of related laws. Appropriate standards are required for the technical skills for remodeling the aircraft system, design verification for airworthiness of the aircraft, and supplemental type certification (STC) certification procedures for type certification. This study analyzes the current status and demand of domestic aircraft remodeling, examines the current supplementary type certification procedure, and diagnoses the problem. In addition, as a result of researching measures to improve remodeling technology and certification capabilities to extend the life of the aircraft, improvements in the education system were derived to improve the domestic additional type certification process, such as approval of remodeling agencies and appointment of qualifications for each professional technician.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.106-112
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• 2021

In this study, we performed a design and structural analysis of a blade-shaped antenna installation on the rear fuselage of a rotary wing aircraft operated by the military. When the structure is damaged while the aircraft is in operation, it is separated from the aircraft main structure and may collide with the rotor or blades to cause the aircraft to crash. Therefore, structural safety for the modified structure must be secured. The design requirement for the newly installed modified part were established, and the load condition was constructed by applying the load that may occur in the aircraft after the modification. Structure safety for the modified structure was secured by performing structure analysis. To analysis stress and deformation of aircraft structure, we developed finite element model and verified it by using hand calculation method. We confirmed the safety of the modified structure through the final structural integrity analysis.

• Journal of IKEEE
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• v.26 no.2
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• pp.257-264
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• 2022

As it takes a lot of time and money to develop an aircraft, an environment for renovating and using existing operating aircraft has been created. As a result, many old aircraft were renovated, and due to the aging of the aircraft, more demanding cable requirements were required for renovation projects, and as the number of equipment inside the aircraft gradually increased, the difficulty of system integration increased. In order to solve the difficulties of system integration through systematization of verification procedures, this paper explains VSWR, I-loss, which are the main indicators of antenna cable modification, and explains DTF, one of the problem detection methods. It also explains the elements required for cable design, the environment to be measured, and procedures, and introduces the overall process and effect of antenna cable improvement through demonstration cases.

• Defense and Technology
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• no.9 s.247
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• pp.74-79
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• 1999

과거는 항공기의 야간임무 수행시 항법장비와 계기에 의존하여 작전을 수행하였다. 이것은 조종사로 하여금 비행 안정감을 주지 못하여 심리적 작전 저해요소로 작용하였다. 따라서, 야간 비행시에도 낮과 유사한 비행조건을 만들어주는 장비 즉, 야시장비체계 개발이 본격화 되었다. 야시장비가 장착된 항공기를 탑승하기 위해서는 야간 투시경(NVG)이 필요하며 항공기 내, 외부 조명의 개조가 전제되어야 한다. 이 글에서는 항공기 야시장비체계 개조의 필요성과 적용실례를 들어 야시장비체계에 대하여 소개하고자 한다.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.87-94
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• 2023

This paper addresses the installation and modification design of airframe structures for new and modified equipment installations that are essential for aircraft performance improvement. Typical performance improvement equipment mounted on the exterior of the aircraft include antenna, radar, electro-optical/infrared (EO/IR), and self-protection system equipment, which require structural reinforcement, modification, and mounting design of the green aircraft for operation. In the interior of the aircraft, console and rack structures are modified or added according to user operation requirements. In addition, this is accompanied by the installation design of equipment to be replaced and added for performance improvement, and the according modification of environmental control system components for internal cooling. The engineering process and cases in which airworthiness was verified through the detailed design of airframe structures with structural integrity, operability, and maintainability of performance-improved aircraft are presented.

• 시스템엔지니어링워크숍
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• s.6
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• pp.157-162
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• 2005

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.1983-1989
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• 2012

This paper presents the stability analysis of UH-60 helicopter with external store such like chaff/flare dispenser. An external store can affect the natural frequency of the aircraft and induce the resonance, which cause the failure of structures. In this paper, therefore, Rayleigh method is used to investigate the resonance with aircraft and external store, and transmission formula is used to determine the vibration load. Structural analysis with local modeling method are performed to present the robust design of aircraft with external store. The ground and flight test are also done to verify the stability of the aircraft.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.8
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• pp.551-557
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• 2022

LRU (Line Replacement Unit) modifications are often required for military aircraft due to aging. Recently, LRU modifications were proceeded for KA-O (Armed Airborne Controller) by replacing the ejection seat and adding avionic equipment, which made the aircraft's operational CG (Center of Gravity) on fuel consumption curve become out of the range of the specification requested. The off-ranged CG should be corrected by introducing an appropriate method. This study proposes a procedure for revising and verifying the empty weight CG altered due to LRU modification for small military aircraft (e.g., KA-O). In the proposed method, first, the change of empty weight CG of KA-O due to the LRU modifications is comprehensively examined. Then, several ballast masses are added to the engine mount strut to restore the empty weight CG on the fuel consumption curve to a safe operational range. The installations are verified via stress and fatigue analysis for various operating conditions. Considering that open information is not very available for the revision of empty weight CG, this study is valuable because it presents an established procedure for correcting and verifying empty weight CG during aircraft modification.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.54-61
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• 2020

For operating military aircraft, military certificate of airworthiness (MCA) must be obtained from military authority. Among procedures of general airworthiness certification, there is a military type certification process that aircraft design complies with military airworthiness certification criteria. The Surion is the first military rotorcraft which has obtained military type certificate, production validation and airworthiness certificate in Korea, and the Surion derivatives for special mission are being operated for government services. Based on Aviation Safety Act, in order to operate the Surion derivatives (military aircraft) for special purpose (such as emergency patient transportation and firefighting), the issuance of special airworthiness certificates was needed from civil airworthiness authority, and the restricted category type certification (RTC) is one of design approvals for special airworthiness certification to be streamlined. This study discussed the procedures for acquiring RTC for special purpose operation of the Surion derivatives classified as military derived aircraft, and suggested procedural ideas to improve Korean RTC system.

• Journal of the KSME
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• v.32 no.7
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• pp.581-587
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• 1992

가스터빈 엔진의 설계는 압축기와 터빈의 효율 이외에도 여러 가지 현실적인 요소가 커다란 영 향을 미치므로 이러한 것들이 설계시에 고려되어야 하며 기존의 기술수준과 부품을 가능한 한 활용하는 것이 현명하다. 특히 산업용 터빈의 개발을 위한 시제 엔진 설계시에는 이러한 접근 방법이 현실적으로 성공 가능성이 크다. 예를 들어서, 기술축적과 연구를 위해서 산업용 엔진을 개발하고자 할 때에 엔진 전부를 설계하는 것보다는 구하기가 용이한 기존의 소형 항공기 엔진의 가스발생기 부분 (압축기, 연소기, 압축기 터빈으로 구성된 부분)을 개조하여 활용하고 동력터 빈과 동력전달 부분만을 자체 설계하여 결합시켜서 개발한다든가 하는 것이 효과적일 것이다.