Journal of the American Helicopter Society (J AM HELICOPTER SOC)

Publisher: American Helicopter Society

Journal description

Current impact factor: 0.63

Impact Factor Rankings

2015 Impact Factor Available summer 2015
2013 / 2014 Impact Factor 0.627
2012 Impact Factor 0.514
2011 Impact Factor 0.549
2010 Impact Factor 0.393
2009 Impact Factor 0.254
2008 Impact Factor 0.467
2007 Impact Factor 0.426
2006 Impact Factor 0.575
2005 Impact Factor 0.443
2004 Impact Factor 0.464
2003 Impact Factor 0.474
2002 Impact Factor 0.59
2001 Impact Factor 0.469
2000 Impact Factor 0.273
1999 Impact Factor 0.493
1998 Impact Factor 0.329
1997 Impact Factor 0.655
1996 Impact Factor 0.5
1995 Impact Factor 0.116
1994 Impact Factor 0.114
1993 Impact Factor 0.364
1992 Impact Factor 0.464

Impact factor over time

Impact factor
Year

Additional details

5-year impact 0.57
Cited half-life 0.00
Immediacy index 0.07
Eigenfactor 0.00
Article influence 0.30
Website Journal of the American Helicopter Society website
Other titles Journal of the American Helicopter Society
ISSN 0002-8711
OCLC 1827576
Material type Periodical
Document type Journal / Magazine / Newspaper

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents an integrated approach targeting the multidisciplinary design of optimum powerplant configurations for rotorcraft at mission level. A single-objective and multiobjective particle swarm optimizer is coupled with a comprehensive rotorcraft mission analysis code. The combined approach is applied for the design and optimization of a reference twin-engine light civil rotorcraft modeled after the Bo105 configuration, manufactured by Airbus Helicopters. Through the implementation of a single-objective optimization strategy, optimum engine design configurations are acquired in terms of mission fuel consumption, engine weight, and gaseous emissions at constant technology level. Multiobjective optimization analyses are carried out to quantify the optimum interrelationship between mission fuel consumption and gaseous emissions. The acquired optimum thermodynamic cycles are subsequently deployed for the design of conceptual regenerative engines for rotorcraft, targeting improved mission fuel economy, enhanced payload–range capability, as well as reduced environmental impact.
    Journal of the American Helicopter Society 03/2015; 60(2):1-12. DOI:10.4050/JAHS.60.022003
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    ABSTRACT: Recent advances in understanding deformation and failure mechanisms of polymer–matrix composites used in rotor structures enable accurate and efficient measurement of material stiffness, strength, and fatigue characteristics based on testing small unidirectional laminate specimens. Successful failure predictions provided increased confidence in the development of virtual test methods replacing some of the standard tests of multidirectional laminated composite materials with three-dimensional models accurately predicting deformation, damage topography, strength, and cycles to failure. However, the remaining key questions are related to the ability of transitioning the material-scale virtual test information to larger composite structures. This work presents results of the feasibility assessment targeting the scaling of knowledge and methods acquired at the material scale, to larger structural elements. In particular, manufacturing irregularities such as voids and fiber waviness are typical attributes of composite rotor structures. Therefore, a comprehensive structural analysis should be able to model such irregularities to predict structural strength and fatigue behavior.
    Journal of the American Helicopter Society 01/2015; 60(1):1-10. DOI:10.4050/JAHS.60.011002
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    ABSTRACT: Three-dimensional numerical computations using ONERA's structured elsA code and the unstructured DLR-TAU code are compared with the OA209 finite wing experiments in static stall and dynamic stall conditions at a Mach number of 0.16 and a Reynolds number of 1 × 106. The DLR-TAU computations were run with the Spalart—Allmaras and Menter shear stress transport (SST) turbulence models, and the elsA computations were carried out using the Spalart—Allmaras and the k—ω Kok + SST turbulence models. Although comparable grids were used, the static simulations show large discrepancies in the stall region between the structured and unstructured approaches. Large differences for the three-dimensional dynamic stall case are obtained with the computations using the Spalart—Allmaras turbulence model showing trailing edge separation only in contrast to the leading edge stall in the experiment. The three-dimensional dynamic stall computations with the two-equation turbulence models are in good agreement with the unsteady pressure measurements and flow field visualizations of the experiment, but also show a shift in the stall angle compared to the experiment. The analysis of the flow field around the finite wing using the numerical simulations reveals the evolution of the Ω-shaped vortex, generated by the interaction of the blade tip vortex.
    Journal of the American Helicopter Society 01/2015; 60(3). DOI:10.4050/JAHS.60.032004
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    ABSTRACT: Anthropometric test devices (ATDs), commonly referred to as crash test dummies, are effective tools used to conduct aerospace safety evaluations. In this study, the latest finite element (FE) model of the Test Device for Human Occupant Restraint (THOR) dummy was simulated under vertical impact conditions based on data recorded in a series of drop tests conducted at the NASA Langley Research Center (LaRC). The purpose of this study was threefold. The first was to improve and then evaluate this FE model for use in a vertical loading environment through kinematic and kinetic response comparisons. The second was to evaluate dummy injury criteria under variable impact conditions. The last was to determine the response sensitivity of the FE model with respect to its pre-impact postural position. Results demonstrate that the updated FE model performs well under vertical loading and predicts injury criteria values close to those recorded in testing. In the postural sensitivity study, the head injury criteria (HIC) response and peak lumbar load (LL) show to be primarily sensitive to the pre-impact head angle and thorax angle, respectively. The promising results shown by the dummy model recommends its use in impact simulations with vertical deceleration pulses close to those used in this study. In addition, it is believed that assigning accurate viscoelastic material properties to the deformable parts of the model may further increase the model fidelity for a larger range of impacts.
    Journal of the American Helicopter Society 01/2015; 60(2):1-10. DOI:10.4050/JAHS.60.022004
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    ABSTRACT: The unsteady flow around the pitching helicopter main rotor blade airfoil EDI-M109 was experimentally investigated at conditions similar to those existing on a retreating rotor blade in forward flight. High speed pressure measurements and hot film anemometry were used to investigate the unsteady transition characteristics of the airfoil. Results are presented for dynamic test points with attached flow, light dynamic stall and deep dynamic stall at M = 0.3 and Re = 1.8 x 10^6. The results include the discussion of the periodicity of the hot film signals for different flow states. The transition process of the pitching airfoil is analyzed and the significance of the intermittent region is described. A time delay between the transition and the model motion is discussed and a linear relationship between the transition position and the time is observed. The influences of the pitching amplitude on the transition characteristics are discussed and the flow separation initiating dynamic stall is analyzed.
    Journal of the American Helicopter Society 01/2014; 59(1):1-12. DOI:10.4050/JAHS.59.012001
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    ABSTRACT: The experimental investigation of constant blowing air jets as fluidic control devices for helicopter dynamic stall control is described. A carbon fiber airfoil of constant OA209 cross section was fitted with a pneumatic system to deliver dry compressed air as jets for flow control at total pressures of up to 10 bar. The experiment used porthole jets of radius 1% chord, positioned at 10% chord and with spacing 6.7% chord. The positive dynamic stall control effects were demonstrated at Mach 0.3, 0.4, and 0.5 for deep dynamic stall test cases with the best test cases reducing the pitching moment peak after the main stall by 83% while increasing the mean lift over one pitching cycle by 30%. The conclusions from the experiments are supported by three-dimensional unsteady Reynolds-averaged Navier–Stokes (URANS) computations of the pitching airfoil with flow control using the DLR-TAU code.
    Journal of the American Helicopter Society 10/2013; 58(4). DOI:10.4050/JAHS.58.042001
  • Journal of the American Helicopter Society 10/2013; 58(4).
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    ABSTRACT: Parasite drag on rotorcraft can become a crucial factor in forward flight, especially during high-speed flight. Prior evaluations of the ability of computational methods to predict hub drag have focused on the ability of these solvers to match model-scale experimental data, but the results have not typically been examined for full-scale conditions. Using an unstructured computational method, the sources of hub drag on a moderately complex model are examined at different Reynolds number scales. Correlations with a 1/3.5-scale wind tunnel test and empirical data are provided to confirm the accuracy of the computations. Unlike prior efforts, grid adaptation that crosses overset mesh boundaries permits grid refinement where needed while minimizing the computational cost. For the moderately complex hub evaluated, utilization of the same grid is permissible, provided the boundary layer grid is tailored for the highest Reynolds number studied and that grid adaptation is applied. Drag evaluation illustrates that the drag of each component should be estimated at the component-level Reynolds number before consideration of the interference effects. Estimation of the interference drag for rotating hubs should additionally account for the Magnus effect, which influences the nonlinearities observed in scaling the drag and the wake.
    Journal of the American Helicopter Society 07/2013; 58(3-3):1-13. DOI:10.4050/JAHS.58.032002
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    ABSTRACT: A computational investigation of the effect of rotation on two-dimensional (2D) deep dynamic stall has been undertaken, showing that the effect of rotation is to reduce the severity of the pitching moment peak and cause earlier reattachment of the flow. A generic single blade rotor geometry was investigated, which had a pitching oscillation around the quarter chord axis while in hover, causing angle-driven dynamic stall. The results at the midpoint of the blade have the same Mach number (0.31), Reynolds number (1.15×106), and pitching motion (α =13◦±7◦) as a dynamic stall test case for which significant experimental wind tunnel data and 2D computations exist. The rotating blade is compared with 2D computations and computations using the same blade without rotation at Mach 0.31 and with the same pitching motion. All test cases involve geometries propagating into undisturbed flow with no downwash. The three-dimensional (3D) grid computed without rotation had lower lift at the reference section than for a 2D computation with the same geometric angle of attack time history, and the lift overshoot classically observed for Spalart–Allmaras turbulence models during 2D dynamic stall was significantly reduced in the 3D case. Rotation reduced the strength of the dynamic stall vortex, which reduced the accompanying pitching moment peak by 25%.
    Journal of the American Helicopter Society 07/2013; 58(3):1-9. DOI:10.4050/JAHS.58.032001
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    ABSTRACT: The flow over an OA209 airfoil subjected to a sinusoidal pitching motion under dynamic stall conditions and equipped with an innovative Deployable Vortex Generator actuator inducing stall control is experimentally and numerically investigated. Pressure and TR-PIV measurements allow a detailed comparison to be performed between clean and controlled cases, including separation point detection and Proper Orthogonal Decomposition analysis. Along with wind tunnel testing, numerical simulations are performed by solving the Unsteady RANS equations with the ONERA elsA code. Computations are successfully compared to the experimental reference and bring further understanding of the Deployable Vortex Generator actuation.
    Journal of the American Helicopter Society 07/2013; Vol. 58(2013-3):1-13. DOI:10.4050/JAHS.58.032005
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    ABSTRACT: In this paper, a mathematical model of a helicopter NO TAil Rotor (NOTAR) antitorque system is developed for real-time flight simulations. The model consists of the circulation control tail boom, direct jet thruster, and the vertical stabilizers. The airflow inside the tail boom is modeled by dividing the flow into aerodynamic control volumes. The model features a bladeelement-type approach for modeling the mass flow through the axial fan blades as well as aerodynamic mass and momentum conservation calculations in each control volume. The side force produced by the direct jet thruster and circulation control tail boom is calculated at different flight conditions. A simple rectangular plan form with symmetrical airfoil shape is used to model the vertical tail. The developed NOTAR antitorque model is integrated with a nonlinear helicopter model. Flight tests are performed on the MD600N, and the data obtained are used for verification. Results show a reasonable match between the model and flight-test data in the antitorque response in hover and forward flight to pilot pedal input.
    Journal of the American Helicopter Society 04/2013; 58(2):1-9. DOI:10.4050/JAHS.58.022002
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    ABSTRACT: Flight testswith a German Army SikorskyCH-53G helicopter were performed to evaluate the applicability and repeatability of the U.S. Army’s Aeronautical Design Standard (ADS)-33E-PRF cargo helicopter handling qualities requirements. The objectives were to corroborate earlier findings and to propose modifications if deemed necessary. The CH-53G was chosen because it is the largest helicopter operated by the German Army, and its dedicated role is cargo and troop transport. The quantitative criteria and the associated boundaries as specified in the standard were largely confirmed. Several flight test maneuvers were revised and tailored. Generally, the heights for performing the near-earth maneuvers were increased. The time/tolerances experienced were borderline desired/adequate or adequate.
    Journal of the American Helicopter Society 01/2013; 58(2013-01-01-1):1-11. DOI:10.4050/JAHS.58.012002