Racing boats operate under high-speed conditions and repetitive rapid maneuvers, where the performance of the propulsion system plays a critical role in race outcomes. The propeller is a key component that converts engine rotational power into thrust and must maintain structural stability under high rotational speeds and hydrodynamic loading. In this study, a racing boat propeller based on a carbon fiber reinforced plastic(CFRP) laminate structure was designed and a manufacturing process was established. The proposed propeller consists of a two-blade configuration in which the hub and blades are integrated into a single structure to minimize structural discontinuity under high rotational conditions. The composite propeller was fabricated using a prepreg lay-up process followed by vacuum-assisted thermal curing. In addition, flat laminate panels with the same carbon fiber lay-up configuration as the propeller were simultaneously manufactured to prepare bending test specimens for process verification. Flexural tests were conducted to evaluate the mechanical characteristics of the CFRP laminate structure. The results of this study provide fundamental data for the design and manufacturing of lightweight CFRP-based racing boat propellers.

This study investigates hybrid propulsion for UAM & AAM as demand shifts toward short-range urban and suburban mobility enabled by advances in lightweight aircraft technologies. Urban low-altitude operations with frequent takeoffs and landings under stricter noise regulations require both high propulsion efficiency and low acoustic emissions. While electric propulsion provides precise controllability and low vibration, limitations in battery energy density and charging infrastructure constrain range, endurance, and turnaround. Hybrid propulsion can mitigate these constraints by combining the high energy density of fuel with the motor’s low-noise, fast-response operation. Accordingly, this study quantitatively compares thrust performance and noise spectra of an identical propeller when driven by an electric motor versus an internal combustion engine, providing baseline evidence to support hybrid propulsion system design.

본 연구는 2019년부터 2024년까지 대한민국 연안 해역에서 발생한 부유물 감김사고의 시·공간적 분포 특성을 종합적으로 분석 하였다. 커널 밀도 추정(KDE), 히트맵 기법을 적용하여 사고 발생의 밀도 변화, 고위험 해역의 형성 및 이동 경향을 규명하였다. 분석 결 과, 서해와 남해는 전 기간에 걸쳐 일관된 고밀도 분포를 보였으며, 2022~2023년에는 서해 북부, 2021·2024년에는 제주 남부 해역에서 사고 집중 현상이 뚜렷하게 나타났다. 또한 특정 연도에는 사고 분포가 전 해역으로 확산되거나 다핵성 패턴을 보였다. 이러한 결과는 부유물 감김사고가 단순한 항로 밀도뿐 아니라 해양쓰레기 이동 경로, 해양환경 변화, 정책 집행 강도 등에 의해 영향을 받는다는 점을 시사한다. 연구는 향후 동적 해양안전 정책 수립, 실시간 위험 예측 시스템 개발, 그리고 고위험 해역에 대한 선제적 관리 전략 마련을 위한 기초 자료로 활용될 수 있다.

본 논문에서는 상반회전 추진 프로펠러 이중축계의 회전 동특성을 정밀하게 분석하기 위한 수치해석 방법을 제안하였다. 제안된 해석 기법은 티모쉔코 보 이론 기반의 유한요소법을 이용하여 자이로스코픽 효과와 베어링 감쇠를 포함한 운동방정식을 정식화하였 다. 개발된 해석 코드는 기존 동축 회전체 모델과의 비교를 통해 검증되었으며, 고유진동수와 캠벨선도 결과가 매우 잘 일치함을 확인 하였다. CRP 축계의 시뮬레이션 결과 1차 공진모드에서 내축의 변위가 외축보다 커 축간 충돌 가능성이 높은 것으로 나타났다. 베어 링 강성 증가 시 고유진동수가 상승하여 공진영역을 회피할 수 있었으며, 축 직경 변화는 상대적으로 영향이 작았다. 제안된 해석 기 법은 상반회전 추진 이중축계의 설계 평가 및 진동 안정성 분석에 유용하게 활용될 수 있으며, 향후에는 비선형 베어링 특성 및 유체– 구조 연성효과를 포함한 확장 연구로 발전시킬 수 있을 것이다.

This study evaluated the design, fabrication, and performance of CFRP composite propeller blades for naval applications. The blades were designed with a sandwich structure and a dovetail hub connection to achieve both high strength and reduced weight. During fabrication, the outer skin and Melamine Foam core were bonded using adhesive films and integrated through autoclave molding and post-curing. The finished blades were coated with a low-gloss urethane clear finish, and the leading-edge areas received additional coating to ensure surface protection and operational identification. Static bending tests and finite element analysis were conducted to assess failure behavior under maximum load and local stress concentrations, while natural frequency measurements(Hammer test) confirmed agreement between analytical and experimental results, verifying the reliability of dynamic response predictions. The results demonstrate that the composite blades offer superior weight reduction and vibration damping compared to metal counterparts and can serve as a foundational reference for future naval propeller design and optimization of various rotating and winged structures.

This study examines the impact of Propeller blade pitch angle mismatch on Noise, thrust, and vibration in light aircraft. Tests were conducted using a simulator with one blade set at increased pitch angles (10°, 12°, 14°) compared to the standard 8°. Results showed that mismatches increased vibration (above 0.26 IPS), Noise levels, and caused operational issues such as fuel leakage and backfire. While thrust initially increased with pitch, it dropped at 14° due to fuel flow instability. These results highlight the need for strict pitch alignment tolerances to ensure optimal performance and safety in aircraft maintenance and operation.

Aircraft Noise is a sound that humans do not want. In this study, based on the Rotax 914 engine used in Korea, the Propeller blade angle was changed by 1 degree for the 3-leaf “K company” Propeller and the 3-leaf “G” wooden Propeller, and the engine RPM was changed to examine the Noise and thrust changes. The purpose of this study is to check whether Noise and thrust loss are the least at the engine's maximum RPM, and to propose an aircraft operation plan in the noisy aerodrome area based on the values. This research further seeks to identify optimal propeller configurations that balance acoustic performance and thrust efficiency. The results are expected to aid in formulating guidelines for quieter flight operations near populated areas.

This study explores the application of Blade Element Theory (BET) to predict the aerodynamic performance of three-dimensional propellers, addressing the computational challenges associated with traditional methods like moving mesh and Multiple Reference Frame (MRF). By utilizing two-dimensional flow analysis to compute lift and drag coefficients, this approach enables rapid and efficient aerodynamic performance predictions with significant reductions in computational time. Comparative analysis with three-dimensional simulations reveals BET's accuracy, with thrust predictions showing slight overestimation at higher RPMs. Findings highlight BET's potential for preliminary propeller design, particularly for low-solidity, low-speed applications. This method provides an efficient alternative for optimizing propeller performance in electric vertical takeoff and landing (eVTOL) systems, pivotal for advancing Urban Air Mobility (UAM) solutions.

Noise is defined as ‘unwanted sound’ or ‘undesired sound’. Recently, the aviation industry has been rapidly developing through convergence with cutting-edge technologies such as UAM. Accordingly, it is expected that new aviation industry models will continue to be created in Korea. In addition, it is expected that aircraft noise will be raised as a new social problem. The characteristic of aircraft noise is that it has a wide transmission range. Therefore, the area affected by aircraft noise is extensive, and the damage area varies depending on the flight path and flight environment. Additionally, it tends to occur continuously in certain areas. This study is an extension of the previous studies 􋺷Study on noise measurement and analysis of C172 aircraft at Muan Airport􋺸 and 􋺷Study on noise measurement and analysis of SR20􋺸, and investigated the noise characteristics of various piston engine trainer aircraft operated in Korea. We want to measure and analyze noise.

최근 딥러닝은 자기공명영상 검사에서의 화질 개선을 위해 다양하게 활용되고 있다. 하지만 다양한 자기공명영상 검사에서 딥러닝이 적용된 기법과 상황에 대한 평가는 부족한 편이다. 이에 본 연구에서는 모션 ACR(American College of Radiology) 팬텀을 활용하여 일반적인 상황과 움직이는 상황에서 T2-PROPELLER(periodically, rotated overlapping parallel lines with enhanced reconstruction, PROPELLER)와 T2-FSE(fast spin echo, FSE) 기법의 화질을 비교 평가해 보고자 하였다. 연구 결과 움직이지 않는 상황에서의 딥러닝 프로세스를 적용하였을 때 유의미한 신호대잡음비와 대조대잡음비의 상승을 보였다. 하지만 팬텀에 움직임을 주는 동적인 상황 에서 딥러닝 프로세스를 적용하였을 때 유의미한 화질 개선을 보이지 않았다. 이러한 결과는 딥러닝 프로세스를 절대 적으로 사용하기보다 다양한 상황에 맞게 선택적으로 적용하는 것이 필요할 것으로 사료된다.

Advancements in technology for large aircraft have led to the development of new materials for aviation. Traditional alloy-based components in aircraft, once prevalent, are now being replaced by composite materials that offer superior performance in terms of strength and operational limits. Notably, propellers have evolved from wood to composite materials, finding application in contemporary small aircraft. In this context, there is a need for research on the composite propellers of the 3-blade "W Company," based on the widely used Rotax 914 engine in South Korea. This study aims to investigate the changes in noise and thrust corresponding to variations in propeller blade angles and engine RPM, with the goal of selecting the optimal propeller pitch angle. Particularly, the "W Company's" propellers are durable and cost-effective, widely adopted in domestic aircraft. The research seeks to propose an effective method to minimize noise while maintaining the necessary thrust, contributing to the smooth operation of aircraft and promoting coexistence with local communities.

In the past, aviation technology developed from wood to alloys to composite materials. Propellers have also evolved from wood to composite materials for modern small aircraft. In this context, research is needed on a three-blade composite propeller based on the Rotax 912 engine, which is widely used in Korea. In this study, the goal is to select the optimal propeller pitch angle by investigating noise changes according to changes in blade angle and engine 4000RPM of three types of three-blade propellers different from each propeller manufacturer. By comparing the noise of the three types of propellers most commonly used in Korea and suggesting the minimum noise blade angle for each propeller, we aim to help aircraft operators select propellers and resolve noise complaints around airfields.