Investigation of Rotor Performance and Loads of a UH-60A Individual Blade Control System

Yeo, Hyeonsoo; Romander, Ethan A.; Norman, Thomas R.

doi:10.4050/jahs.56.042006

Cited by 11 publications

(8 citation statements)

References 12 publications

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“…Thus, for four-bladed lift-offset coaxial rotor systems such as the X2TD rotor, it is investigated that the application of IBC with an actuation of 2/rev can reduce rotor vibration and simultaneously improve (or at least maintain the baseline value) performance. Similarly, when IBC is applied to the UH-60A rotor, which is a single main rotor with four blades, 2/rev actuation greatly influences both the vibration and performance of the rotor (Yeo et al , 2010). However, when the HHC, which is another active rotor control, is applied, the 2/rev actuation is not available for the X2TD rotor because the actuator, located below the swashplate, induces the blade pitch motion.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

Active vibration reductions of a lift-offset compound helicopter using individual blade pitch control with multiple harmonic inputs

Kwon

Hong

Park

et al. 2022

AEAT

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Purpose The purpose of this study is to use the individual blade pitch control (IBC), reduce actively both the rotor hub vibratory loads and airframe vibration responses for the lift-offset compound helicopter at a high-speed flight condition. Design/methodology/approach The Sikorsky X2 technology demonstrator (X2TD) is used as the lift-offset compound helicopter. The X2TD lift-offset rotor is modelled and its rotor hub vibratory loads at a flight speed of 250 knots are predicted using a rotorcraft comprehensive analysis code, CAMRAD II, and the airframe structural dynamics is represented with a finite element analysis code, MSC.NASTRAN. When the propulsive trim methodology is applied for rotor trim, the best input condition for IBC using multiple harmonic inputs is searched to reduce the rotor vibration, while the rotor aerodynamic performance (the rotor effective lift-to-drag ratio) is improved or maintained at least. Finally, the reduction in airframe vibration responses is investigated when the best input condition for IBC with multiple harmonics is applied to the lift-offset rotor. Findings When the IBC with the single harmonic input using the 2/rev actuation frequency, amplitude of 2° and control phase angle of 120° (2P/2°/120°) is considered for X2TD rotor, the rotor vibration is reduced by about 26.37% only and the rotor effective lift-to-drag ratio increases slightly by 0.98%. When X2TD rotor uses the IBC with multiple harmonic inputs (2P/2°/45° + 5P/1°/90°), the rotor hub vibratory loads and airframe vibration responses are reduced by 44.69% and from 0.48 to 79.10%, respectively, while rotor effective lift-to-drag ratio is improved by 0.77%, as compared to the baseline without IBC. Originality/value This study is the first study to use the 2/rev actuation for IBC to the four-bladed lift-offset coaxial rotor and to investigate to obtain simultaneously the rotor vibration reduction, rotor performance improvement and airframe vibration reduction, using IBC with multiple harmonic inputs.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

Active vibration reductions of a lift-offset compound helicopter using individual blade pitch control with multiple harmonic inputs

Kwon

Hong

Park

et al. 2022

AEAT

View full text Add to dashboard Cite

show abstract

“…Among applied codes the following could be mentioned: CAMRAD (Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics) developed for NASA and US Army, FLIGHTLAB developed in USA by Advanced Rotorcraft Technology, Inc., DYMORE developed at the Georgia Institute of Technology and German-French HOST (Helicopter Overall Simulation Tool) developed by DLR and ONERA. Flight test measurements [3,4] and wind tunnel investigations [10] provide data for verification the analytical methods applied for defining loads of helicopter rotor. Introduction CFD/CSD methods [1,9] which couple computational fluid dynamics and analysis of flexible body dynamics allows to improve the accuracy of prediction the rotor blades loads.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Boundary States of Helicopter Flight

Stanisławski

2019

Journal of KONES

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Results of simulation of main rotor blade loads and deformations, which can be generated during boundary states of helicopter flight, are presented. Concerned cases of flight envelope include hover at maximum height, level flight at high velocity, pull-up manoeuvres applying cyclic pitch and mixed collective and cyclic control. The simulation calculations were executed for data of light helicopter with three-bladed articulated rotor. For analysis, the real blades are treated as elastic axes with distributed masses of blade segments. The model of deformable blade allows for out-of-plane bending, in plane bending, and torsion. For assumed flight state of helicopter, the equations of rotor blades motion are solved applying Runge-Kutta method. According to Galerkin method, for each concerned azimuthal position of blade the parameters of its motions are assumed as a combination of considered bending and torsion eigen modes of the blade. The loads of rotor blades generated during flight depend due to velocity of flight, helicopter mass, position of rotor axis in air and deflections of swashplate that correspond to collective and cyclic pitch angle applied to rotor blades. The results of simulations presenting rotor loads and blade deformations are shown in form of time-runs and as plots of rotor-disk distributions. The simulations of helicopter flight states may be useful for prediction the conditions of flight-tests without exceeding safety boundaries or may help to define limitations for manoeuvre and control of helicopter.

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“…Norman et al (2009) carried out an IBC control experiment on UH-60A rotor system in the National Full-Scale Aerodynamics Complex (NFAC) wind tunnel, proving that the IBC can effectively reduce the required power of the rotor under certain parameter settings [9]. During the numerical analysis of the IBC control system, Yeo et al (2011) integrated the free-wake method (FWM) and the FWM/ computational fluid dynamics (CFD) coupling method into the numerical model for flow field calculation, and compared the calculated results with the experimental data [12,13]. The comparison shows that the FWM/CFD coupling method is more accurate than the FWM in most cases.…”

Section: Introductionmentioning

confidence: 99%

VPM/CFD-Based Research on Rotor Performance and Loads of Individual Blade Control Rotor System

2018

Teh. vjesn.

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This paper aims to explore the effect of individual blade control (IBC) on aerodynamic performance of helicopter rotor and explain its formation mechanism. For this purpose, the vortex particle method (VPM)-computational fluid dynamics (CFD) coupling method was proposed to calculate rotor aerodynamic performance under open-loop IBC active control. Specifically, the near-blade flow field was calculated by the CFD method, while the far-field flow field was solved by the VPM method. In this way, the entire flow field was computed through the information interaction between the two calculated fields. Then, the UH-60A rotor was selected as an example to verify the established VPM/CFD method. First, the proposed method was proved valid; then, the effect of control frequency and phase on the helicopter performance was analysed under different forward flight conditions; finally, the mechanism of IBC control was examined by comparing the lift coefficient distribution and the induced inflows of the optimal control and the worst control. The results showed that proper IBC control parameters can lower the required power of the rotor to some extent, but the optimal control parameters vary with flight states. Comparatively, the lift distribution is more even and the induced flows are less fluctuating under optimal control than under worst control.

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Investigation of Rotor Performance and Loads of a UH-60A Individual Blade Control System

Cited by 11 publications

References 12 publications

Active vibration reductions of a lift-offset compound helicopter using individual blade pitch control with multiple harmonic inputs

Active vibration reductions of a lift-offset compound helicopter using individual blade pitch control with multiple harmonic inputs

Simulation of Boundary States of Helicopter Flight

VPM/CFD-Based Research on Rotor Performance and Loads of Individual Blade Control Rotor System

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