• 항공우주기술
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• 제11권1호
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• pp.185-191
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• 2012

본 논문에서는 축소 로터의 성능시험과 축소 헬기 Flight Test Bed 개발이 가능한 헬리콥터 섀시다이나모미터(HCDS)를 개발하여 지상시험을 수행하였다. 축소 헬기는 엔진 출력에 따른 컬렉티브 피치각의 상호 관계로부터 로터의 일정 회전속도에 대한 추력과 동력의 변화를 확인하고, 그 결과로 OGE에서의 정지비행효율(F.M.)이 0.76으로 비행시험 가능성을 점검하였다. 본 헬리콥터 섀시다이나모미터(HCDS) 시험 결과는 축소 헬기 개발과 로터 블레이드의 성능 평가에 활용할 것이다.

• 한국항공운항학회지
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• 제15권3호
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• pp.15-23
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• 2007

In this paper, we deducted the missions with respect to Korea utility helicopter (KUH) and consist of the scenarios which describe proper purpose of KUH. And so developed fatigue load spectrum of KUH by applying Helix that is fatigue load spectrum for blade of articulated helicopter rotor system. The developed load spectrum is applied to fatigue analysis of blade by modeled finite element with stress-life method (S-N). And we compared the result of fatigue analysis to prior to Helix for the sake of verifying the load spectrum that we generated.

• 소음진동
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• 제7권5호
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• pp.819-826
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• 1997

The finite element analyses of a composite hingeless rotor blade in forward flight have been performed to investigate the influence of blade design parameters on the blade stability. The blade structure is represented by a single cell composite box-beam and its nonclassical effects such as transverse shear and torsion-related warping are considered. The nonlinear periodic differential equations of motion are obtained by moderate deflection beam theory and finite element method based on Hamilton principle. Aerodynamic forces are calculated using the quasi-steady strip theiry with compressibility and reverse flow effects. The coupling effects between the rotor blade and the fuselage are included in a free flight propulsive trim analysis. Damping values are calculated by using the Floquet transition matrix theory from the linearized equations perturbed at equilibrium position of the blade. The aeroelastic results were compared with an alternative analytic approch, and they showed good correlation with each other. Some parametric investigations for the helicopter design variables, such as pretwist and precone angles are carried out to know the aeroelastic behavior of the rotor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1385-1389
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• 2005

This paper describes the design, analysis and manufacture procedure of the composite blade for hingeless rotor system of unmanned helicopters. Helicopter rotor system is the key structural unit that produces thrust and control forces for intended flight conditions. In this work, a hingeless rotor system is adopted, and base on the design requirements for rotor system, composite blade section design and calculation of material properties were performed. In order to avoid the unstable state such as resonance, vibration characteristics of rotor system were analyzed. Finally, this paper describes the forming and manufacture of composite blade.

• 한국정밀공학회지
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• 제27권3호
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• pp.73-79
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• 2010

A preliminary study on a length-variable rotor blade for a small unmanned helicopter has been conducted. After surveys on previous researches, and examining requirements for application to a small unmanned helicopter, a length-variable rotor blade was designed and manufactured to be driven by centrifugal force from rotor revolution with no mechanical actuator. The rotor blade was divided into a fixed inboard section and an outboard section sliding in span-wise direction. In order to determine the operating conditions of the length-variable rotor during revolution, and to derive the design variables of extension spring and rotor weight, a series of analyses from multi-body dynamics solution were conducted. The manufactured prototype was verified of its length-varying mechanism from a rotor stand, the results and required future improvements are discussed.

• Journal of Mechanical Science and Technology
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• 제14권3호
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• pp.291-297
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• 2000

Modern helicopter rotor blades with non-homogeneous cross sections, composed of anisotropic material, require highly sophisticated structural analysis because of various cross sectional geometry and material properties. They may be subjected by the combined axial, bending, and torsional loading, and the dynamic and static behaviors of rotor blades are seriously influenced by the structural coupling under rotating condition. To simplify the analysis procedure using one dimensional beam model, it is necessary to determine the principal coordinate of the rotor blade. In this study, a method for the determination of the principal coordinate including elastic and shear centers is presented, based upon continuum mechanics. The scheme is verified by comparing the results with confirmed experimental results.

• 한국군사과학기술학회지
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• 제8권3호
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• pp.33-41
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• 2005

This paper describes the conceptual design of medium size helicopter rotor system. Based on assumed design requirements, trade-off study for rotor configuration has been conducted in terms of rotor tip speed, disk loading, blade area, solidity, etc for estimated primary mission gross weight. For the main rotor, four-blade and five-blade rotors are studied with the conventional tail rotor. The performance analysis for baseline configuration is conducted using a helicopter performance analysis program. The analysis shows design results satisfy the design requirements.

• 한국항공우주학회지
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• 제46권8호
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• pp.671-678
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• 2018

헬리콥터 소음예측은 저소음 헬리콥터 기술 개발에 필수적인 과정이다. 본 논문에서는 헬리콥터 통합성능해석프로그램 CAMRAD-II와 자체개발한 소음해석코드를 이용하여 소음예측 기법을 구축하였다. 또한 헬리콥터 소음 중 가장 큰 원인인 블레이드-와류 간섭 소음을 분석하여 해석기법을 검증하였다. 실제적인 소음예측을 위해 국제민간항공기구(ICAO)에서 기준으로 하고 있는 헬리콥터 소음 측정 비행조건인 Flyover, Approach 조건에 대해서 소음해석을 수행하였으며, 최종적으로 비행시험결과 와의 비교 분석을 통해 해석방법의 적합성을 확인하였다.

• 한국항공우주학회지
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• 제41권9호
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• pp.726-733
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• 2013

헬리콥터 로터 블레이드는 헬리콥터의 성능을 좌우하는 동시에 비행 시 주된 소음을 발생함에 따라 고성능, 저소음 특성이 요구되는 구상품이다. 국내 소형무장헬기 개발과 병행하여 개발될 민수헬기는 해외체계업체 보유 민수헬기를 기반으로한 국제공동 업그레이드 개발이 추진됨에 따라 해외체계업체 제시 대상기종의 로터 블레이드 성능파악이 매우 중요하다. 본 연구는 해외체계업체 제시 대상기종 블레이드의 성능분석을 통하여 최신 해외 블레이드 대비 성능파악 및 국내고유형상 블레이드 개발 가능성을 타진하는 것을 목적으로 수행되었다. 본 연구의 결과는 일차적으로 향후 민수헬기개발사업의 해외협상 및 국내 고유형상 블레이드 개발 시 목표 성능지표 등으로 활용될 수 있다.

• 한국전산유체공학회지
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• 제14권1호
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• pp.53-61
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• 2009

The objective of this research is to design blade planform to reduce high speed impulsive(HSI) noise from a non-lifting helicopter rotor using CFD method and optimization techniques. As for the aero-acoustic analysis, CFD technique for aerodynamic analysis and Kirchhoff's method for the acoustic analysis were used. As for the optimization method, Kriging-based genetic algorithm(GA) model as a high-fidelity optimization method was chosen. Design variables and constraints are determined for arbitrary blade planform. The result shows that the optimized blade planform with high swept-back and taper ratio can reduce HSI noise by suppressing generation of the strong shock wave on blade surface and propagation of the noise to the farfield flow region.