• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.726-733
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• 2013

The rotor blade of helicopter is the core component determining helicopter performance and requiring low noise and low vibration because the blade becomes the major source of noise during flight. The performance analysis of candidates rotor blades is very critical because LCH(Light Civil Helicopter) will be developed parallel with LAH(Light Armed Helicopter) as an international upgrade program based on the existing platform of foreign civil helicopter. This research was aimed to recognize the performance of the candidates rotor blades compared with the newly developed foreign rotor blades and to investigate the feasibility about developing korea unique shape rotor blades by analysis the rotor performance and noise. The result of this research can be used for the target performance index during negotiation with foreign helicopter company and developing korea unique shape rotor blades.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.8
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• pp.784-790
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• 2012

This paper describes a stability and dynamic characteristics of bearingless helicopter main rotor in hover. Baseline rotor configuration is defined and modal analysis for the configuration is taken to verify the dynamic characteristics. The kinematic pitch-lag couplings through ways of pitch link installation are analyzed to know effects on loads, frequencies and stability. The effects of pitch link attachments in spanwise direction and chordwise direction as well as pitch link inclination on thrust, power, flpa-lag-pitch mode frequencies and inplane damping are examined. Pitch link at trailing edge location in chordwise direction has influence on aeroelastic stability of the rotor. Also, the pitch link with negative inclination angle makes inplane damping increase.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.394-399
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• 2012

This paper describes a stability and dynamic characteristics of bearingless helicopter main rotor in hover. Baseline rotor configuration is defined and modal analysis for the configuration is taken to verify the dynamic characteristics. The kinematic pitch-lag couplings through ways of pitch link installation are analyzed to know effects on loads, frequencies and stability. The effects of pitch link attachments in spanwise direction and chordwise direction as well as pitch link inclination on thrust, power, flpa-lag-pitch mode frequencies and inplane damping are examined. Pitch link at trailing edge location in chordwise direction has influence on aeroelastic stability of the rotor. Also, the pitch link with negative inclination angle makes inplane damping increase.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.902-905
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• 2004

Recently, the composite materials are widely used for manufacturing the helicopter rotor blades. furthermore, composites show great potential on the design of rotor blades due to the advantages of strength, durability and weight of the materials. To keep with this advantages, it is necessary to calculate natural frequencies of a rotating blades for avoiding resonance. In this paper, the structural design process of airfoil cross section is introduced, and natural frequencies of composite rotor blades with variable rpm we investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.369-370
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.187-188
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• 2010

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.6
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• pp.557-567
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• 2015

The most decisive factor of major sources of a helicopter is the main rotor system and the rotor-induced vibration is one of the technical challenges which should be resolved to ensure comfort for crews and passengers. Passive vibration reduction devices are adopted in conventional helicopters and several types of passive devices are also used in Surion. In recent years, foreign helicopter manufactures have increasingly applied the application of AVCS (active vibration control system) because of their superior performance with lower weight compared to passive device. In addition to weight reduction, AVCS has advantages maintaining its performance over aircraft configuration changes and flight condition changes. The technology demonstration program was performed in order to validate the performance of AVCS when applied to Surion, and optimization process for finding optimal configuration of sensors and actuators. Optimal configuration was produced using ground and flight test data, and its performance was evaluated and compared with flight test result.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.99-104
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• 2003

This paper described the general dynamic point for rotor design and the design procedure of low vibration blade. Generally, rotor rotating natural frequencies are determined to minimize hub loads, blade vibration and to suppress ground resonance at rotor design stage. First, through rotor frequency diagram, natural frequencies must be far away from resonance point and rotating loads generated from blade can be transformed to non-rotating load to predict fuselage vibration. Vibration level was predicted at each forward flight condition by calculating cockpit's vertical acceleration transferred from non-rotating hub load assuming a fuselage as a rigid body. This design method is applied to design current Next-generation Rotor System Blade(NRSB) and will be applied to New Rotor which will be developed Further.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.56-57
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1000-1007
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• 2007

In this study, structural vibration analyses of a smart unmanned aerial vehicle (UAV) have been conducted considering dynamic hub-loads of tilt rotor. Practical computational structural dynamics technique based on the finite element method is applied using MSC/NASTRAN. The present UAV(TR-S5-04) finite element model is constructed as a full three-dimensional configuration with different fuel conditions and tilting angles for helicopter, transient and airplane flight modes. In addition, the 3-dimensional supporting equipment structures of electronic devices are considered for vibration analysis. As the results of this study, transient structural displacements and accelerations are presented in detail. Moreover, vibration characteristics of structural parts and installed equipments are investigated for different fuel conditions and tilting angles.