• Title/Summary/Keyword: Helicopter Noise

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Multi-Mode Radar System Model Design for Helicopter (헬기탑재 다중모드 레이다 시스템 모델 설계)

  • Kwag, Young-Kil;Bae, Jae-Hoon
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.208-212
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    • 2003

  • An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the conceptual design results of the multi-mode pulsed Doppler radar system testbed model for helicopter. Due to the inherent flight nature of the hovering vehicle which is flying in low-altitude and low speed, as well as rapid maneuvering, the moving clutters from the platform should be suppressed by using a special MTD (Moving Target Detector) processing. For the multi-mode radar system model design, the flight parameters of the moving helicopter platform were assumed: altitude of 3 Km, average cruising velocity of 150knots. The multi-mode operation capability was applied such as short-range, medium-range, and long-range depending on the mission of the vehicle. The nominal detection ranges is 30 Km for the testbed experimental model, but can be expanded up to 75 Km for the long range weather mode. The detection probability of each mode is also compared in terms of the signal-to noise ratio of each mode, and the designed radar system specifications ate provided as a design results.

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Dynamic Characteristic Study of Hingeless Blade Stiffness Reinforcement for Bearingless Rotor Whirl Tower Test (무베어링 로터 훨타워 시험을 위한 무힌지 블레이드 강성보강에 따른 동특성 연구)

  • Kim, Taejoo;Yun, Chulyong;Kee, Youngjoong;Kim, Seung-Ho;Jung, Sungnam
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.2
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    • pp.105-111
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    • 2013

  • Whirl tower test is conducted basically during helicopter rotor system development process. And for whirl tower test of rotor hub system, new design blade or existing blade which is remodeled for new rotor hub system is used. Because of simple shape and efficient aerodynamic characteristic, BO-105 helicopter blade is used for helicopter rotor hub development project widely. Originally BO-105 blade is used for hingeless hub system and blade root is used to flexure. So flap stiffness and lag stiffness at blade root area is relatively low compare with airfoil area. So, in order to apply the BO-105 blade to bearingless hub, blade root area have to be reinforced. And in this process, blade root area's section property is changed. In this paper, we suggest reinforcement method of BO-105 blade root area and study dynamic characteristic of bearingless rotor system with reinforcement BO-105 blade.

  • https://doi.org/10.5050/KSNVE.2013.23.2.105 인용 PDF KSCI

Ground Resonance Instabilities Analysis of a Bearingless Helicopter Main Rotor (무베어링 헬리콥터 로터의 지상공진 불안정성 특성 해석)

  • Yun, Chul-Yong;Kee, Young-Jung;Kim, Tae-Joo;Kim, Deog-Kwan;Kim, Seung-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.4
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    • pp.352-357
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    • 2012

  • The ground resonance instability of a helicopter with bearingless main rotor hub were investigated. The ground resonance instability is caused by an interaction between the blade lag motion and hub inplane motion. This instability occurs when the helicopter is on the ground and is important for soft-inplane rotors where the rotating lag mode frequency is less than the rotor rotational speed. For the analysis, the bearingless rotor was composed of blades, flexbeam, torque tube, damper, shear restrainer, and pitch links. The fuselage was modeled as a mass-damper-spring system having natural frequencies in roll and pitch motions. The rotor-fuselage coupling equations are derived in non-rotating frame to consider the rotor and fuselage equations in the same frame. The ground resonance instabilities for three cases where are without lead-lag damper and fuselage damping, with lead-lag damper and without fuselage damping, and finally with lead-lag damper and fuselage damping. There is no ground resonance instability in the only rotor-fuselage configuration with lead-lag damper and fuselage damping.

  • https://doi.org/10.5050/KSNVE.2012.22.4.352 인용 PDF KSCI

Application of Piezoelectric-based Actuators to Helicopter Vibration Reduction (4)

  • Kim, Jun-Sik
    • Journal of KSNVE
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    • v.20 no.6
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    • pp.24-28
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    • 2010

  • Many methodologies have been explored to reduce helicopter vibration. Trailing edge flaps for such a purpose have been studied for the past twenty years. A brief overview of the introduction of active vibration controls using trailing edge flaps and smart actuators is presented in series. This is the fourth article, in which a piezoelectric resonant actuation system with a buckling-beam motion amplifier for active trailing edge flaps is presented.

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