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Journal articles on the topic 'Helicopter rotor blade design'
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1
Stalewski, Wienczyslaw, and Wieslaw Zalewski. "Performance improvement of helicopter rotors through blade redesigning." Aircraft Engineering and Aerospace Technology 91, no. 5 (May 13, 2019): 747–55. http://dx.doi.org/10.1108/aeat-01-2018-0009.
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Purpose The purpose of this paper is to determine dependencies between a rotor-blade shape and a rotor performance as well as to search for optimal shapes of blades dedicated for helicopter main and tail rotors. Design/methodology/approach The research is conducted based on computational methodology, using the parametric-design approach. The developed parametric model takes into account several typical blade-shape parameters. The rotor aerodynamic characteristics are evaluated using the unsteady Reynolds-averaged Navier–Stokes solver. Flow effects caused by rotating blades are modelled based on both simplified approach and truly 3D simulations. Findings The computational studies have shown that the helicopter-rotor performance may be significantly improved even through relatively simple aerodynamic redesigning of its blades. The research results confirm high potential of the developed methodology of rotor-blade optimisation. Developed families of helicopter-rotor-blade airfoils are competitive compared to the best airfoils cited in literature. The finally designed rotors, compared to the baselines, for the same driving power, are characterised by 5 and 32% higher thrust, in case of main and tail rotor, respectively. Practical implications The developed and implemented methodology of parametric design and optimisation of helicopter-rotor blades may be used in future studies on performance improvement of rotorcraft rotors. Some of presented results concern the redesigning of main and tail rotors of existing helicopters. These results may be used directly in modernisation processes of these helicopters. Originality/value The presented study is original in relation to the developed methodology of optimisation of helicopter-rotor blades, families of modern helicopter airfoils and innovative solutions in rotor-blade-design area.
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Garipova, Lyaysan Ildusovna, Andrei Sergeevich Batrakov, Alexander Nikolaevich Kusyumov, Sergey Anatolievich Mikhaylov, and George Barakos. "Aerodynamic and acoustic analysis of helicopter main rotor blade tips in hover." International Journal of Numerical Methods for Heat & Fluid Flow 26, no. 7 (September 5, 2016): 2101–18. http://dx.doi.org/10.1108/hff-08-2015-0348.
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Purpose The design of main rotor blade tips is of interest to helicopter manufactures since the tip details affect the performance and acoustics of the rotor. The paper aims to discuss this issue. Design/methodology/approach In this paper, computation fluid dynamics is used to simulate the flow around hovering helicopter blades with different tip designs. For each type of blade tip a parametric study on the shape is also conducted for comparison calculations were performed the constant rotor thrust condition. The collective pitch and the cone angles of the blades were determined by at an iterative trimming process. Findings Analysis of the distributed blade loads shows that the tip geometry has a significant influence on aerodynamics and aeroacoustics especially for stations where blade loading is high. Originality/value The aeroacoustic characteristics of the rotors were obtained using Ffowcs Williams-Hawkings equations.
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Гребеников, А. Г., И. А. Воронько, Ю. В. Дьяченко, В. В. Коллеров, И. В. Малков, В. А. Урбанович, and Н. И. Москаленко. "КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ МЕТАЛЕВИХ ЛОПАТЕЙ НЕСУЧОГО І РУЛЬОВОГО ГВИНТІВ ВЕРТОЛЬОТА." Open Information and Computer Integrated Technologies, no. 87 (June 30, 2020): 5–51. http://dx.doi.org/10.32620/oikit.2020.87.01.
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Analysis of the foreign and domestic work experience, manufacturing and operation of the helicopters with metal blades of the main (MR) and tail (TR) rotors is performed. General requirements for the helicopter MR and TR blades design are formulated. Structural arrangement of the helicopter MR metal blade is reviewed, features of the construction materials for the metal blades are noted. Features of the MR and TR metal blades design with the pressed spar and aluminum honeycomb core are given. Parametric modeling technique of the helicopter MR metal blade is presented. The manufacturing rout technology and the method of the surface strengthening of the metal blade tip are presented. The scheme and the manufacturing rout technology of the pressed aluminum spar are given; the geometrical twist features, the surface strengthening and the assembling of the spar with the blade tip are re- viewed. The features of the electric-heating patch bonding on the spar leading edge are shown. Following technological steps of the blade metal rear area manufacturing are reviewed: the rolled aluminum foil degreasing; the aluminum honeycomb structures manufacturing; the aluminum honeycomb core butt milling. The features of the blade rear area assembling and metal blade assembling by bonding in the jig are presented; the content of works outside of the jig for metal blade of the helicopter main rotor is given.
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Sanchez Ramirez, Andrea, Kallol Das, Richard Loendersloot, Tiedo Tinga, and Paul Havinga. "Wireless Sensor Network for Helicopter Rotor Blade Vibration Monitoring: Requirements Definition and Technological Aspects." Key Engineering Materials 569-570 (July 2013): 775–82. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.775.
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The main rotor accounts for the largest vibration source for helicopter fuselage and components. However, accurate blade monitoring has been limited due to the practical restrictions on instrumenting rotating blades. The use of Wireless Sensor Networks (WSNs) for real time vibration monitoring promises to deliver a significant contribution to rotor performance monitoring and blade damage identification. This paper discusses the main technological challenges for wireless sensor networks for vibration monitoring on helicopter rotor blades. The first part introduces the context of vibration monitoring on helicopters. Secondly, an overview of the main failure modes for rotor and blades is presented. Based on the requirements for failure modes monitoring, a proposition for a multipurpose sensor network is presented. The network aims to monitor rotor performance, blade integrity and damage monitoring at three different scales referred to as macro layer, meso layer and micro layer. The final part presents the requirements for WSNs design in relation with sensing, processing, communication and actuation. Finally power supply aspects are discussed.
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Saravanan, G., Vinoth Kumar Annamalai, N. Bharath, Antonio Kevin, G. Rahul Teja, and Neil Steven Anto. "Design fabrication and performance analysis of length morphing rotor blade." International Journal of Engineering & Technology 7, no. 3.3 (June 8, 2018): 139. http://dx.doi.org/10.14419/ijet.v7i2.33.13871.
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The present work deals with helicopter theory involving the study, design and fabrication of the helicopter rotor blades with the length-morphing mechanism. The research of the rotor blades has enabled in a proper understanding of the aerodynamics and design of the same. The thrust produced by a blade is proportional to its area, and for every motor RPM, maximum thrust efficiency is achieved for a discrete length of the rotor blade. Facing this complexity, designers compute an optimal length for the average motor RPM while designing the heli-copter blades. Acknowledging the challenges, Length-Morphing rotor blades targeting maximum thrust efficiency for each motor RPM was developed with the aid of knowledge in Blade Element Theory. The rotor blade was designed and fabricated to be driven by the centrifugal force from the motor. The rotor blade was divided into fixed inboard section and sliding outboard part in a span-wise direction. The analy-sis was carried out to study and comprehend the operating conditions of the length-variable rotor during revolutions and to derive the design variables of extension-spring and rotor weight. Variation of thrust concerning the length of the rotor blade was studied, and the setup was fabricated. The project aims to enable maximum rotor blade thrust efficiency for each RPM of the motor by varying the length of the rotor blade and computing the performance characteristics of the same.
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Kovalovs, Andrejs, Evgeny Barkanov, and Sergejs Gluhihs. "ACTIVE TWIST OF MODEL ROTOR BLADES WITH D-SPAR DESIGN." TRANSPORT 22, no. 1 (March 31, 2007): 38–44. http://dx.doi.org/10.3846/16484142.2007.9638094.
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The design methodology based on the planning of experiments and response surface technique has been developed for an optimum placement of Macro Fiber Composite (MFC) actuators in the helicopter rotor blades. The baseline helicopter rotor blade consists of D‐spar made of UD GFRP, skin made of +450/‐450 GFRP, foam core, MFC actuators placement on the skin and balance weight. 3D finite element model of the rotor blade has been built by ANSYS, where the rotor blade skin and spar “moustaches” are modeled by the linear layered structural shell elements SHELL99, and the spar and foam ‐ by 3D 20‐node structural solid elements SOLID 186. The thermal analyses of 3D finite element model have been developed to investigate an active twist of the helicopter rotor blade. Strain analogy between piezoelectric strains and thermally induced strains is used to model piezoelectric effects. The optimisation results have been obtained for design solutions, connected with the application of active materials, and checked by the finite element calculations.
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Sałaciński, Michał, Rafał Kowalski, Michał Szmidt, and Sławomir Augustyn. "A New Approach to Modelling and Testing the Fatigue Strength of Helicopter Rotor Blades during Repair Process." Fatigue of Aircraft Structures 2019, no. 11 (December 1, 2019): 56–67. http://dx.doi.org/10.2478/fas-2019-0006.
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AbstractThe fatigue test was carried out on an element of a rotor blade removed from the Mi-2 helicopter. The purpose of the test was to check the fatigue strength of the repaired rotor blade. Metal composite rotor blades have a metal spar in the form of a box and the trailing sections in the form of metallic honeycomb sandwich panels. The trailing sections are bonded to the spar. The repair had been carried out at the point where the trailing section became debonded from the spar at the Air Force Institute of Technology in Warsaw using a methodology developed for carrying out repairs of rotor blades’ damage. All types of the Mi family helicopters are equipped with metal composite rotors blades. Depending on MTOW (Maximum Take-Off Weight) and destination of helicopters, blades differ in dimensions, but their design solutions are practically the same. For this reason, the developed repair methodology can be used for all characteristic rotor blades structures for Mi helicopters. The fatigue test was performed at the Łukasiewicz - Institute of Aviation in Warsaw, using a hydraulically driven fatigue machine. The fatigue test was carried out by performing over 1.1 million load cycles. In repair places, upon completion of fatigue testing, no damage was found.
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Stanislawski, Jaroslaw. "A simulation investigation of helicopter ground resonance phenomenon." Aircraft Engineering and Aerospace Technology 91, no. 3 (March 4, 2019): 484–97. http://dx.doi.org/10.1108/aeat-11-2017-0256.
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Purpose The purpose of this paper is to present a simulation method applied for investigation of helicopter ground resonance phenomenon. Design/methodology/approach The considered physical model of helicopter standing on ground with rotating rotor consists of fuselage and main transmission gear treated as stiff bodies connected by elastic elements. The fuselage is supported on landing gear modeled by spring-damper units. The main rotor blades are treated as set of elastic axes with lumped masses distributed along blade radius. Due to Galerkin method, parameters of blades motion are assumed as a combination of bending and torsion eigen modes. A Runge–Kutta method is applied to solve equations of motions of rotor blades and helicopter fuselage. Findings The presented simulation method may be applied in preliminary stage of helicopter design to avoid ground resonance by proper selection of landing gear units and blade damper characteristics. Practical implications Ground resonance may occur in form of violently increasing mutual oscillations of helicopter fuselage and lead-lag motion of rotor blades. According to changes of stiffness and damping characteristics, simulations show stable behavior or arising oscillations of helicopter. The effects of different blade balance or defect of blade damper are predicted. Originality/value The simulation method may help to determine the envelope of safe operation of helicopter in phase of take-off or landing. The effects of additional disturbances as results of blades pitch control as swashplate deflection are introduced.
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Kizhakke Kodakkattu, Saijal, Prabhakaran Nair, and Joy M.L. "Design optimization of helicopter rotor using kriging." Aircraft Engineering and Aerospace Technology 90, no. 6 (September 3, 2018): 937–45. http://dx.doi.org/10.1108/aeat-12-2016-0250.
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Purpose The purpose of this study is to obtain optimum locations, peak deflection and chord of the twin trailing-edge flaps and optimum torsional stiffness of the helicopter rotor blade to minimize the vibration in the rotor hub with minimum requirement of flap control power. Design/methodology/approach Kriging metamodel with three-level five variable orthogonal array-based data points is used to decouple the optimization problem and actual aeroelastic analysis. Findings Some very good design solutions are obtained using this model. The best design point in minimizing vibration gives about 81 per cent reduction in the hub vibration with a penalization of increased flap power requirement, at normal cruise speed of rotor-craft flight. Practical implications One of the major challenges in the helicopters is the high vibration level in comparison with fixed wing aircraft. The reduction in vibration level in the helicopter improves passenger and crew comfort and reduces maintenance cost. Originality/value This paper presents design optimization of the helicopter rotor blade combining five design variables, such as the locations of twin trailing-edge flaps, peak deflection and flap chord and torsional stiffness of the rotor. Also, this study uses kriging metamodel to decouple the complex aeroelastic analysis and optimization problem.
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Ignatkin, Yurii M., Pavel V. Makeev, and Alexander I. Shomov. "CALCULATED RESEARCH OF INFLUENCE OF HELICOPTER MAIN ROTORS GEOMETRY ON THE EFFICIENCY IN HOVER MODE BASED ON THE NONLINEAR VORTEX MODEL." Civil Aviation High TECHNOLOGIES 21, no. 6 (December 26, 2018): 43–53. http://dx.doi.org/10.26467/2079-0619-2018-21-6-43-53.
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The efficiency of the helicopter main rotor in the hover mode is very important, because this mode essentially determines the performance characteristics of the helicopter. A feature of the helicopter rotor aerodynamics is a significant inductive blade influence that highly defines its aerodynamic characteristics. The problem of the influence of the blade twist and spatial geometric layout of the main rotor on its aerodynamic characteristics in the hover mode for a fixed value of the rotor solidity has been considered in this article. As a criterion of efficiency of the rotor in the hover mode relative efficiency (FoM – Figure of Merit) is used. The results are obtained by numerical simulation based on the nonlinear vortex blade model of the rotor, developed at the Helicopter Design Chair of the MAI. The model allows taking into account a complicated spatial shape of the free vortex path of the rotor blades that determines their inductive interaction. As the example of a four-blade main rotor with rectangular blades in plan, the influence of the value of the blades twist on the efficiency in the hover mode is studied. For different values of the rotor thrust, the values and ranges of the blade twist angles are determined, providing the maximum positive effect of the efficiency increase in hovering. For a fixed value of the blade twist, the rotor solidity, and the same operating conditions, the effect of various schemes and configurations of rotor on its efficiency in hover mode is studied. A single rotor with a different number of blades (from 2 to 6), an X-shaped rotor, coaxial rotor and rotor with crossed blades type "synchropter" are considered. The values of the efficiency increase in hovering depending on the rotor layout in comparison with the two-blade rotor are obtained. The comparative analysis of inductive velocities and streamlines for the "synchropter" rotor scheme, coaxial rotor scheme and its equivalent single rotor scheme is presented. The obtained results can be useful at the stage of preliminary design of vertically taking-off aircraft when selecting the parameters of their main rotor system.
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Shahmiri, Farid, Maryam Sargolzehi, and Mohammad Ali Shahi Ashtiani. "Systematic evaluation of the helicopter rotor blades: design variables and interactions." Aircraft Engineering and Aerospace Technology 91, no. 9 (October 7, 2019): 1223–37. http://dx.doi.org/10.1108/aeat-06-2018-0163.
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Purpose The effects of rotor blade design variables and their mutual interactions on aerodynamic efficiency of helicopters are investigated. The aerodynamic efficiency is defined based on figure of merit (FM) and lift-to-drag responses developed for hover and forward flight, respectively. Design/methodology/approach The approach is to couple a general flight dynamic simulation code, previously validated in the time domain, with design of experiment (DOE) required for the response surface development. DOE includes I-optimality criteria to preselect the data and improve data acquisition process. Desirability approach is also implemented for a better understanding of the optimum rotor blade planform in both hover and forward flight. Findings The resulting system provides a systematic manner to examine the rotor blade design variables and their interactions, thus reducing the time and cost of designing rotor blades. The obtained results show that the blade taper ratio of 0.3, the point of taper initiation of about 0.64 R within a SC1095R8 airfoil satisfy the maximum FM of 0.73 and the maximum lift-to-drag ratio of about 5.5 in hover and forward flight. Practical implications The work shows the practical possibility to implement the proposed optimization process that can be used for the advanced rotor blade design. Originality/value The work presents the rapid and reliable optimization process efficiently used for designing advanced rotor blades in hover and forward flight.
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Pölzlbauer, Patrick, Andreas Kümmel, Damien Desvigne, and Christian Breitsamter. "Numerical Investigation of an Optimized Rotor Head Fairing for the RACER Compound Helicopter in Cruise Flight." Aerospace 8, no. 3 (March 5, 2021): 66. http://dx.doi.org/10.3390/aerospace8030066.
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The present work is part of the Clean Sky 2 project Full-Fairing Rotor Head Aerodynamic Design Optimization (FURADO), which deals with the aerodynamic design optimization of a full-fairing rotor head for the Rapid And Cost-Effective Rotorcraft (RACER) compound helicopter. The rotor head is a major drag source and previous investigations have revealed that the application of rotor head fairings can be an effective drag reduction measure. As part of the full-fairing concept, a new blade-sleeve fairing was aerodynamically optimized for cruise flight. Within this publication, the newly developed blade-sleeve fairing is put to test on an isolated, five-bladed rotor head and compared to an already existing reference blade-sleeve fairing, which was developed at Airbus Helicopters. Numerical flow simulations are performed with ANSYS Fluent 2019 R2 considering a rotating rotor head with cyclic pitch movement. The aerodynamic forces of the isolated rotor head are analyzed to determine the performance benefit of the newly developed blade-sleeve fairing. A drag reduction of 4.7% and a lift increase of 20% are obtained in comparison to the Airbus Helicopters reference configuration. Furthermore, selected surface and flow field quantities are presented to give an overview on the occurring flow phenomena.
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Dalli, Uğbreve;ur, and Şcedilefaatdin Yüksel. "Identification of Flap Motion Parameters for Vibration Reduction in Helicopter Rotors with Multiple Active Trailing Edge Flaps." Shock and Vibration 18, no. 5 (2011): 727–45. http://dx.doi.org/10.1155/2011/675791.
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An active control method utilizing the multiple trailing edge flap configuration for rotorcraft vibration suppression and blade loads control is presented. A comprehensive model for rotor blade with active trailing edge flaps is used to calculate the vibration characteristics, natural frequencies and mode shapes of any complex composite helicopter rotor blade. A computer program is developed to calculate the system response, rotor blade root forces and moments under aerodynamic forcing conditions. Rotor blade system response is calculated using the proposed solution method and the developed program depending on any structural and aerodynamic properties of rotor blades, structural properties of trailing edge flaps and properties of trailing edge flap actuator inputs. Rotor blade loads are determined first on a nominal rotor blade without multiple active trailing edge flaps and then the effects of the active flap motions on the existing rotor blade loads are investigated. Multiple active trailing edge flaps are controlled by using open loop controllers to identify the effects of the actuator signal output properties such as frequency, amplitude and phase on the system response. Effects of using multiple trailing edge flaps on controlling rotor blade vibrations are investigated and some design criteria are determined for the design of trailing edge flap controller that will provide actuator signal outputs to minimize the rotor blade root loads. It is calculated that using the developed active trailing edge rotor blade model, helicopter rotor blade vibrations can be reduced up to 36% of the nominal rotor blade vibrations.
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Balaji, K. "Design and Development of Main Helicopter Rotor Blade." International Journal for Research in Applied Science and Engineering Technology V, no. IV (March 25, 2017): 74–77. http://dx.doi.org/10.22214/ijraset.2017.4013.
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Bernardini, G., E. Piccione, A. Anobile, J. Serafini, and M. Gennaretti. "Optimal Design and Acoustic Assessment of Low-Vibration Rotor Blades." International Journal of Rotating Machinery 2016 (2016): 1–17. http://dx.doi.org/10.1155/2016/1302564.
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An optimal procedure for the design of rotor blade that generates low vibratory hub loads in nonaxial flow conditions is presented and applied to a helicopter rotor in forward flight, a condition where vibrations and noise become severe. Blade shape and structural properties are the design parameters to be identified within a binary genetic optimization algorithm under aeroelastic stability constraint. The process exploits an aeroelastic solver that is based on a nonlinear, beam-like model, suited for the analysis of arbitrary curved-elastic-axis blades, with the introduction of a surrogate wake inflow model for the analysis of sectional aerodynamic loads. Numerical results are presented to demonstrate the capability of the proposed approach to identify low vibratory hub loads rotor blades as well as to assess the robustness of solution at off-design operating conditions. Further, the aeroacoustic assessment of the rotor configurations determined is carried out in order to examine the impact of low-vibration blade design on the emitted noise field.
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Roy, Arunabha M. "Finite Element Framework for Efficient Design of Three Dimensional Multicomponent Composite Helicopter Rotor Blade System." Eng 2, no. 1 (March 1, 2021): 69–79. http://dx.doi.org/10.3390/eng2010006.
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In the present study, a three-dimensional finite element framework has been developed to model a full-scale multilaminate composite helicopter rotor blade. Tip deformation and stress behavior have been analyzed for external aerodynamic loading conditions and compared with the Abaqus FEA model. Furthermore, different parametric studies of geometric design parameters of composite laminates are studied in order to minimize tip deformation and maximize the overall efficiency of the helicopter blade. It is found that these parameters significantly influence the tip deformation characteristic and can be judiciously chosen for the efficient design of the rotor blade system.
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Afagh, F. F., F. Nitzsche, and N. Morozova. "Dynamic modelling and stability of hingeless helicopter blades with a smart spring." Aeronautical Journal 108, no. 1085 (July 2004): 369–77. http://dx.doi.org/10.1017/s0001924000005182.
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AbstractThe aeroelastic stability of a uniform, untwisted hingeless ‘smart’ helicopter rotor blade in hover has been analysed. The concept of a ‘smart’ blade is achieved by implementing a piezoelectric stack at an appropriate location along a host blade such that upon actuation it enters the load path becoming an integral part of the host structure. Thus, the stiffness characteristics of the rotor are altered causing modal damping augmentation of the blade. The perturbation equations of motion for the ‘smart’ blade that describe the unsteady blade motion about the equilibrium operating condition are obtained using Galerkin’s method. These differential equations with periodic time coefficients are analysed for stability utilising the Floquet method. Six different regimes of actuation are investigated, and a parametric study is carried out by considering six different design cases. It is shown that, compared to a ‘host’ blade the stability characteristics of the ‘smart’ blade are not affected adversely. In fact, a judicious design and actuation of the ‘smart’ spring has the potential of improving the stability boundaries of individual blades.
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Awal, Ziad Bin Abdul, and Mohd Shariff bin Ammoo. "A Case Study on the Air Flow Characteristics of the Hirobo-FALCON 505 Controllable Helicopter's Main Rotor Blade." Applied Mechanics and Materials 527 (February 2014): 39–42. http://dx.doi.org/10.4028/www.scientific.net/amm.527.39.
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The aerodynamics of the helicopter rotor is one of the most elating and exigent tribulations faced by the aerodynamicists today. Study through flow visualization process plays a key role in understanding the airflow distinctiveness and vortex interaction of the helicopter main rotor blade. Inspecting and scrutinizing the effects of wake vortices during operation is a great challenge and imperative in designing effective rotor system. This study aimed to visualize the main rotor airflow pattern of the Hirobo-FALCON 505 controllable subscale helicopter and seek for the vortex flow at the blade tip. The experimental qualitative data is correlated with quantitative data to perform scrupulous study on the airflow behavior and characteristics along with its distinctiveness spawned by the main rotor blade. Simulation using design software is performed in analogous stipulations to endow with comparability between the flow visualization results. Throughout the blade span several dissimilar flow patterns have been identified. The main rotor hub has turbulent flow at its center due to low energy of air amassed in this region whereas in the middle portion of the rotor blade, the air encompasses high kinetic energy with a clear straight streamline pattern.
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Murugan, M. S., R. Ganguli, and D. Harursampath. "Surrogate based design optimisation of composite aerofoil cross-section for helicopter vibration reduction." Aeronautical Journal 116, no. 1181 (July 2012): 709–25. http://dx.doi.org/10.1017/s0001924000007181.
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AbstractDesign optimisation of a helicopter rotor blade is performed. The objective is to reduce helicopter vibration and constraints are put on frequencies and aeroelastic stability. The ply angles of the D-spar and skin of the composite rotor blade with NACA 0015 aerofoil section are considered as design variables. Polynomial response surfaces and space filling experimental designs are used to generate surrogate models of the objective function with respect to cross-section properties. The stacking sequence corresponding to the optimal cross-section is found using a real-coded genetic algorithm. Ply angle discretisation of 1°, 15°, 30° and 45° are used. The mean value of the objective function is used to find the optimal blade designs and the resulting designs are tested for variance. The optimal designs show a vibration reduction of 26% to 33% from the baseline design. A substantial reduction in vibration and an aeroelastically stable blade is obtained even after accounting for composite material uncertainty.
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Chattopadhyay, A., and J. L. Walsh. "Application of optimization methods to helicopter rotor blade design." Structural Optimization 2, no. 1 (March 1990): 11–22. http://dx.doi.org/10.1007/bf01743516.
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Kozaczuk, Konrad Jerzy. "Composite technology development based on helicopter rotor blades." Aircraft Engineering and Aerospace Technology 92, no. 3 (October 27, 2018): 273–84. http://dx.doi.org/10.1108/aeat-12-2017-0260.
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Purpose This paper aims to document the approach, effort and cost of advance composite technology implementation suited for small and medium enterprises on the example of composite main rotor blade development for ILX-27 helicopter. Design/methodology/approach This work was carried out as part of a development project for main rotor blades used on the ILX 27 helicopter. The paper presents all stages of the design of the blade structure in parallel with composite technology development. The data were gathered and documented during project execution. The stages of R&D work in terms of labor intensity and important processes influencing quality and efficiency were assessed. Findings The paper provides key aspects for successful composite capability introduction. The incurred cost of equipment and staff training is evaluated. The paper also summarized the cost of composite parts manufactured with developed technology. Practical implications The paper provides detail example of composite capability development including basic technologies, processes, equipment and cost of the project. Presented details can be great guidelines for small and medium enterprises with the goal of composite technology introduction for aerostructures design and manufacturing. Originality/value This paper present clear, complete and verified process of composite capability development for aerostructures design and build suited for small and medium enterprises. It presents detail cost, calculated in Polish economy environment, of each phase and final cost of the product.
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King, S. P. "The minimisation of helicopter vibration through blade design and active control." Aeronautical Journal 92, no. 917 (September 1988): 247–64. http://dx.doi.org/10.1017/s0001924000016250.
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The high level of vibration experienced on the helicopter has been an unfortunate feature of the vehicle throughout its existence, and considerable efforts have been expended over many years in attempts to reduce vibration to levels typical of other forms of transport. Much has been achieved, but as the forward speed increases some components of rotor generated vibration increase very rapidly and consequently, at the increased cruise speed of modern helicopters, vibration can still be high. Also, the requirements have become more stringent, due partly to what the passengers or crew are prepared to tolerate, and partly to the complexity of the tasks required of the crews, especially on military machines.
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Ignácio da Silva, José A., Douglas D. Bueno, and Gustavo L. C. M. de Abreu. "On the controllers' design to stabilize ground resonance helicopter." Journal of Vibration and Control 25, no. 23-24 (September 5, 2019): 2894–909. http://dx.doi.org/10.1177/1077546319873797.
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Ground resonance (GR) in helicopters is a potentially catastrophic instability commonly caused by coalescence of the regressive cyclic blade lag mode with the fuselage motion in certain rotor speed ranges. It can limit the helicopter operational envelope and the design of this type of vehicle can become a difficult task. Although a broad class of actuators allows the use of active and semi-active techniques to design feedback-based control systems, a limited number of works in the literature introduce formulations to compute the controller gain to suppress this phenomenon. Also, commonly, a control approach defines a feedback, particularly to a specific rotor speed. In this context, this work introduces an alternative methodology to design an active control system to stabilize GR of a helicopter. The proposed approach can suppress this instability in all rotor speed ranges by using only one control gain. Two strategies are proposed based on linear matrix inequalities (LMIs). The Lyapunov stability criteria are used and the unstable rotor speed is considered as an uncertain parameter to define an associated convex space. Using convex optimization, a robust control gain is computed until all the unstable rotor speed range is stabilized. Numerical simulations are carried out to demonstrate the effectiveness of this methodology. The results confirm the viability of the proposed approach to design active and semi-active controllers.
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Wang, Zhengzhi, Chunling Zhu, and Ning Zhao. "Experimental Study on the Effect of Different Parameters on Rotor Blade Icing in a Cold Chamber." Applied Sciences 10, no. 17 (August 25, 2020): 5884. http://dx.doi.org/10.3390/app10175884.
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Icing phenomenon is an important problem in helicopter rotor design. Conducting experiments in a cold chamber is one of the main methods used to study the law of rotor icing. The purpose of this paper was to analyze the influence of different parameters on the ice shapes of rotor blade and to obtain the relationship between the ice shapes and the input parameters. The icing experimental platform of rotation blade in a cold chamber was set up, and the rotor icing experiments under various conditions were carried out. The ice shapes on the blade were obtained, and the influence of different icing temperatures, rotation speeds, liquid water content, icing times, number of blades on the rotor, and blade materials on the ice shapes were analyzed. The results showed that the ice thickness on the leading edge increased with the increase of liquid water content, rotation speed, and icing time, and the number and material of blades had little effect on icing. The conclusions of this paper can provide a reference for the rotor numerical simulation and future experimental research.
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Samad, Abdallah, Gitsuzo B. S. Tagawa, François Morency, and Christophe Volat. "Predicting Rotor Heat Transfer Using the Viscous Blade Element Momentum Theory and Unsteady Vortex Lattice Method." Aerospace 7, no. 7 (July 3, 2020): 90. http://dx.doi.org/10.3390/aerospace7070090.
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Calculating the unsteady convective heat transfer on helicopter blades is the first step in the prediction of ice accretion and the design of ice-protection systems. Simulations using Computational Fluid Dynamics (CFD) successfully model the complex aerodynamics of rotors as well as the heat transfer on blade surfaces, but for a conceptual design, faster calculation methods may be favorable. In the recent literature, classical methods such as the blade element momentum theory (BEMT) and the unsteady vortex lattice method (UVLM) were used to produce higher fidelity aerodynamic results by coupling them to viscous CFD databases. The novelty of this research originates from the introduction of an added layer of the coupling technique to predict rotor blade heat transfer using the BEMT and UVLM. The new approach implements the viscous coupling of the two methods from one hand and introduces a link to a new airfoil CFD-determined heat transfer correlation. This way, the convective heat transfer on ice-clean rotor blades is estimated while benefiting from the viscous extension of the BEMT and UVLM. The CFD heat transfer prediction is verified using existing correlations for a flat plate test case. Thrust predictions by the implemented UVLM and BEMT agree within 2% and 80% compared to experimental data. Tip vortex locations by the UVLM are predicted within 90% but fail in extreme ground effect. The end results present as an estimate of the heat transfer for a typical lightweight helicopter tail rotor for four test cases in hover, ground effect, axial, and forward flight.
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Goo, Nam Seo, Hoon Cheol Park, and Kwang Joon Yoon. "Conceptual Design, Thrust Test, and Finite Element Analysis of a Tip-Jet Rotor Using a Small Turbo-Jet Engine." Key Engineering Materials 306-308 (March 2006): 541–46. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.541.
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A general helicopter uses rotary power produced from the installed engine in order to get the directional thrust. In the case of a tip-jet rotor helicopter, the compressed air or the combustion gas passes through a duct system inside rotors and is ejected out of the nozzle at the blade tips to produce torque enough for rotation of the rotor system. The generated torque makes the rotor system rotate, so that it can create the directional thrust. Since the anti-torque does not occur in this tip-jet rotorcraft, the tail rotor can be removed, which can be very attractive. In this paper, a power system for a reduced-scale tip-jet rotor by using a small turbo-jet engine is designed and tested for feasibility study. The in-plane thrust that the power system can produce is measured and compared with the calculated one. Finally, the finite element analysis of a conceptually designed tip-jet rotor is performed to ensure structural safety.
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Pölzlbauer, P., D. Desvigne, and C. Breitsamter. "Aerodynamic design optimization of a helicopter rotor blade-sleeve fairing." CEAS Aeronautical Journal 10, no. 3 (November 12, 2018): 665–85. http://dx.doi.org/10.1007/s13272-018-0341-0.
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Lwin, Tun, Ngoc Anh Vu, Jae-Woo Lee, and Sangho Kim. "A distributed Web-based framework for helicopter rotor blade design." Advances in Engineering Software 53 (November 2012): 14–22. http://dx.doi.org/10.1016/j.advengsoft.2012.07.003.
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Lee, Chang-Bae, KiJoo Jang, Byeong-Uk Im, and SangJoon Shin. "Reverse Design for Composite Rotor Blade of BO-105 Helicopter." Journal of the Korean Society for Aeronautical & Space Sciences 49, no. 7 (July 31, 2021): 539–47. http://dx.doi.org/10.5139/jksas.2021.49.7.539.
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Xie, Jiayi, Zhifeng Xie, Ming Zhou, and Jun Qiu. "Multidisciplinary Aerodynamic Design of a Rotor Blade for an Optimum Rotor Speed Helicopter." Applied Sciences 7, no. 6 (June 20, 2017): 639. http://dx.doi.org/10.3390/app7060639.
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Chan, W., and J. Perry. "Use of aerofoil section dynamic stall synthesis methods in rotor design." Aeronautical Journal 116, no. 1179 (May 2012): 501–20. http://dx.doi.org/10.1017/s0001924000007004.
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Abstract The introduction of the original time delay method of Beddoes, an engineering model for the unsteady response of an aerofoil section including dynamic stall, had a profound effect on the design and development of rotor systems in the UK. Over the years, the model expanded to include more and more features of the unsteady flow, with many contributors. It is now in use throughout the world as part of rotor analysis packages. Nevertheless, it retains its essential simplicity. Work to confirm the ability of the most recent version of the dynamic stall model from the University of Glasgow to replicate the complicated behaviour of an advanced rotor aerofoil section at full scale Reynolds and Mach numbers provides an opportunity to review the use of this new engineering model in the helicopter rotor design environment. This note discusses the application of dynamic stall synthesis methods to the problem of classifying and comparing aerofoil sections when designing rotors for the retreating blade stall condition that determines the rotor blade area requirement of the helicopter. The development of the dynamic stall models employed in UK rotor designs is reviewed in this paper and their use in the design process explained, with emphasis on the assumptions that overcome the limitations of the models and exploit their simplicity, enabling accurate and conservative rotor designs. The paper shows how the model may be used to structure the analysis of complex sets of dynamic aerofoil data. It illustrates how structured comparison between the model and the data yields a concise appreciation of the behaviour of the aerofoil and an understanding of the physical processes involved. Some previously unappreciated effects are identified and the model is used to transfer experience of the aerofoil section behaviour from the non-rotating wind-tunnel environment to that of the rotor. Finally, the application of the new engineering model developed at Glasgow University in the rotor design process is outlined. Some remarks on the use of engineering models in comparison with CFD models in the design context are included.
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Kovalovs, Andrejs, Evgeny Barkanov, and Sergejs Gluhihs. "NUMERICAL OPTIMIZATION OF HELICOPTER ROTOR BLADE DESIGN FOR ACTIVE TWIST CONTROL." Aviation 11, no. 3 (September 30, 2007): 3–9. http://dx.doi.org/10.3846/16487788.2007.9635962.
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The vibration of a helicopter has several different sources, such as the rotor, engine and transmission system. This creates a number of problems with performance, for example poor manoeuvrability, discomfort of the pilot, low fatigue life of the structural components, and, consequently, high operating costs.
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Wilke, Gunther. "Quieter and Greener rotorcraft: concurrent aerodynamic and acoustic optimization." CEAS Aeronautical Journal 12, no. 3 (April 21, 2021): 495–508. http://dx.doi.org/10.1007/s13272-021-00513-x.
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AbstractWithin the DLR project VicToria an aerodynamic and aero-acoustic optimization of helicopter rotor blades is performed. During the optimization, three independent flight conditions are considered: hover, cruise and descent flight. The first two flight conditions drive the power requirements of the helicopter rotor, while the descent flight is the loudest flight condition for current helicopter generations. To drive down the required power and the emitted noise, a multi-objective design approach coupled with surrogate models is utilized to find a Pareto optimal set of rotors. This approach allows to identify the trade-offs to be made when laying emphasis on either goal function. The underlying CFD simulations utilize fourth-order accurate spatial schemes to capture the vortex dominated flow of helicopter rotor blades. The paper presents the validation of the setups, the optimization results and the off-design analysis of a chosen set of blades from the Pareto front. The conclusion is that the utilization of the Pareto front approach is necessary to find good rotor designs, while the utilization of high-order methods allows for efficient CFD setups.
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Shaw, S. T., and N. Qin. "Unsteady flow around helicopter rotor blade sections in forward flight." Aeronautical Journal 103, no. 1019 (January 1999): 35–44. http://dx.doi.org/10.1017/s0001924000065088.
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AbstractThe aerodynamic performance of aerofoils performing unsteady motions is important for the design of helicopter rotors. In this respect the study of aerofoils undergoing in-plane oscillations (translation along the horizontal axis) provides useful insight into the flow physics associated with the advancing blade in forward flight. In this paper a numerical method is developed in which the unsteady thin layer Navier-Stokes equations are solved for aerofoils performing rigid body motions. The method has been applied to the calculation of the flowfield around a NACA 0012 aerofoil performing in-plane motions representative of high-speed forward flight. Comparison of computed pressure data with experimental measurements is generally found to be good. The quantitative differences observed between computations and experiment are thought to have arisen mainly as a consequence of the low aspect ratio of the model rotor employed in the windtunnel tests.
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Hance, Benjamin, J. Gordon Leishman, and Joseph Milluzzo. "Performance Measurements of a 1/6-Scale Model of the 1907 Cornu Rotor." Journal of the American Helicopter Society 57, no. 3 (July 1, 2012): 1–5. http://dx.doi.org/10.4050/jahs.57.032001.
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Measurements of the performance of an approximate 1/6-scale Cornu 1907 rotor system are discussed. The rotor was tested in hover, both in and out of ground effect, over a range of rotational speeds and collective blade pitch angles. The measurements showed that the rotor had low aerodynamic efficiency, with a maximum attainable figure of merit of only about 0.35 for out of ground effect operating conditions. An analysis of the measurements showed that the performance of this rotor is dominated by relatively high induced losses, with an average induced power factor of over two, mainly because of the use of low-aspect-ratio blades. Extrapolation of the performance polar back to zero thrust with the aid of modified momentum theory suggests that the average profile drag coefficient for the blade sections was of the order of 0.1. However, even with the benefits of a proper airfoil section of lower drag, it is shown that without also using a blade design of higher aspect ratio, the figure of merit of the Cornu rotor design could not be improved much above 0.4. The measured results confirm previous modeling assumptions used for the aerodynamic and performance analysis of the Cornu rotor design and conclusions drawn regarding the unfeasibility of successful free flights of the Cornu helicopter.
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Pölzlbauer, P., C. Breitsamter, and D. Desvigne. "Performance improvement of a compound helicopter rotor head by aerodynamic design optimisation of a blade-sleeve fairing." Aeronautical Journal 123, no. 1268 (March 14, 2019): 1456–75. http://dx.doi.org/10.1017/aer.2018.172.
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ABSTRACTWithin the present publication, the rotor head of a compound helicopter known as Rapid And Cost-Effective Rotorcraft (RACER) is investigated. In particular, the aerodynamic design optimisation of the RACER blade-sleeve fairings (BSFs) is conducted. For this purpose, an isolated rotor head is generated featuring a full-fairing beanie, the BSF and a truncated rotor blade (RB). Moreover, a single RB is investigated at two different azimuthal rotor positions, which correspond to the advancing and the retreating RB case. For this purpose, an averaged circumferential velocity is determined in the blade-sleeve region and superposed with the RACER cruise speed in order to estimate the prevailing flow conditions. The automated aerodynamic design optimisation is performed by means of a previously developed optimisation tool chain. A global multi-objective genetic optimisation algorithm is applied for the given problem. During preliminary work, a 2D aerodynamic design optimisation of selected blade-sleeve sections was conducted. These optimised aerofoils represent the design variables for the current optimisation problem. The shape modification of the 3D fairing is realised by exchanging specific aerofoils at certain spanwise sections.
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Kodakkattu, SK, ML Joy, and K. Prabhakaran Nair. "Vibration reduction of helicopter with trailing-edge flaps at various flying conditions." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, no. 4 (August 6, 2016): 770–84. http://dx.doi.org/10.1177/0954410016642460.
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The aim of this study is to find the optimal torsional stiffness and trailing-edge flap locations of the helicopter rotor blade for minimum vibration and flap control power at flap lengths of 6% and 9% of the rotor-blade length. A three level orthogonal array based response surface method using polynomial functions is used to describe both vibration and flap control power. Pareto points minimizing hub vibration and flap control power are found at flap lengths of 6% and 9% of the rotor length. This study also explores the variation in rotor hub vibration and flap control power with flying conditions such as the advance ratio and the thrust-to-solidity ratio at the optimum design points. This gives a useful improved design with about a 60% decrease in hub vibration with a penalization of increased flap power at the normal flying regime of rotor-craft flight.
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Zhang, Chen, and Liyan Zhang. "Model of multidisciplinary simulation integration in helicopter rotor blade design process." International Journal of Computer Integrated Manufacturing 27, no. 3 (July 9, 2013): 229–41. http://dx.doi.org/10.1080/0951192x.2013.812805.
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Sun, Hyosung, and Soogab Lee. "Response surface approach to aerodynamic optimization design of helicopter rotor blade." International Journal for Numerical Methods in Engineering 64, no. 1 (2005): 125–42. http://dx.doi.org/10.1002/nme.1391.
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L. Lvov, Nikolay, Stanislav S. Khabarov, and Mikhail Yu. Gavrikov. "Creation of an Integrated System for Monitoring the Technical Condition of High-Quality Helicopter Units based on Fiber-Optic Technology." International Journal of Engineering & Technology 7, no. 4.38 (December 3, 2018): 1162. http://dx.doi.org/10.14419/ijet.v7i4.38.27755.
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This article discusses the problems of creating an integrated system for monitoring the technical condition of highly responsible helicopter units, and analyzed options for its creation. Fiber-optical technology is considered as a technology, on the basis of which it is possible to build an integrated system, since this technology makes it possible to measure various physical parameters such as vibration, deformation, temperature, acoustic emission and other parameters, and due to the miniature dimensions of the fiber-optic light guide. It can be built into the PCM design, which is a relevant factor due to the growth use of PCM in the design and manufacture of helicopters. The results of bench and flight tests of helicopter pilot and rotor blades with fasteners using fiber optic deformation sensors based on a Bragg fiber grille demonstrate the fundamental possibility of creating a system for monitoring the technical condition of helicopter rotors using fiber optic sensors .Also, there are examples of creating other elements of an integrated monitoring system based on the use of fiber-optic technology, such as a system for signaling the breakdown of air flow and flutter on the helicopter rotor blades, a system for measuring the weight and alignment of helicopter cargo and a system for monitoring the technical condition of the airframe.
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Koushik, Sudarshan N., and Fredric H. Schmitz. "An Experimental and Theoretical Study of Blade–Vortex Interaction Noise." Journal of the American Helicopter Society 58, no. 3 (July 1, 2013): 1–11. http://dx.doi.org/10.4050/jahs.58.032006.
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An experimental method to study helicopter blade–vortex interaction (BVI) noise has been developed. Called the blade-controlled disturbance interaction, the method nearly replicates a rotor BVI by having a single-bladed rotor pass through a stationary gust field specially designed to simulate the highly impulsive induced velocity field of a vortex. This approach can be used to evaluate the effectiveness of blade design changes to noise radiation during a BVI event, as well as to study the effect of different interaction geometries on the resulting noise. The first set of experiments in this facility shows that the directionality of BVI noise radiation is very sensitive to the interaction angle. Oblique interactions spread the acoustics energy over wider azimuth angles compared to parallel interactions, as well as move the peak noise location closer to the rotor plane. Linear two-dimensional unsteady aerodynamic theory predicts the overall directionality trends reasonably well. However, the actual pulse shapes do not match and noise levels are underpredicted, particularly for oblique interactions.
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Kumar, M. Rohin, and C. Venkatesan. "Effects of rotor blade-tip geometry on helicopter trim and control response." Aeronautical Journal 121, no. 1239 (April 10, 2017): 637–59. http://dx.doi.org/10.1017/aer.2017.15.
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ABSTRACTFor performance improvement and noise reduction, swept and anhedral tips have been incorporated in advanced-geometry rotor blades. While there are aerodynamic benefits to these advanced tip geometries, they come at the cost of complicated structural design and weight penalties. The effect of these tip shapes on loads, vibration and aeroelastic response are also unclear. In this study, a comprehensive helicopter aeroelastic analysis which includes rotor-fuselage coupling shall be described and the analysis results for rotor blades with straight tip, tip sweep and tip anhedral shall be presented and compared. The helicopter modelled is a conventional one with a hingeless single main rotor and single tail rotor. The blade undergoes flap, lag, torsion and axial deformations. Tip sweep, pretwist, precone, predroop, torque offset and root offset are included in the model. Aerodynamic model includes Peters-He dynamic wake theory for inflow and the modified ONERA dynamic stall theory for airloads calculations. The complete 6-dof nonlinear equilibrium equations of the fuselage are solved for analysing any general flight condition. Response to pilot control inputs is determined by integrating the full set of nonlinear equations of motion with respect to time. The effects of tip sweep and tip anhedral on structural dynamics, trim characteristics and vehicle response to pilot inputs are presented. It is shown that for blades with tip sweep and tip anhedral/dihedral, the 1/rev harmonics of the root loads reduce while the 4/rev harmonics of the hub loads increase in magnitude. Tip dihedral is shown to induce a reversal of yaw rate for lateral and longitudinal cyclic input.
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Amer, Kenneth B. "Technical Notes: Comment on the “Minimum Weight Design of Helicopter Rotor Blades with Frequency Constraints,” Journal of the American Helicopter Society, October, 1989." Journal of the American Helicopter Society 35, no. 2 (May 1, 1990): 69. http://dx.doi.org/10.4050/jahs.35.2.69.
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It appears that most of the weight saving from the reference blade to the minimum‐weight blade is in the region of the blade root. Undoubtedly, the reference blade requires this weight increase to accommodate the usual bending fatigue loads at the root. The authors do not address the question of how their minimum‐weight blade would handle blade‐root fatigue loads.
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Cao, Yihua, Guozhi Li, and R. A. Hess. "Helicopter flight characteristics in icing conditions." Aeronautical Journal 116, no. 1183 (September 2012): 963–79. http://dx.doi.org/10.1017/s0001924000007375.
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Abstract A method to predict the effects of rotor icing on the flight characteristics of a UH-60A helicopter is presented. By considering both natural ice shedding and different types of ice accretion due to local temperature variations on the blade surface, an improved rotor icing model was developed. Next, the effects of icing on rotor force, torque and flapping were incorporated in a nonlinear helicopter dynamic model. Based upon icing design envelopes in cumuliform clouds, trim and stability characteristics were studied. Further development of the helicopter state-space model allowed control and handling qualities characteristics to be investigated with variation of the three icing-related cloud variables (atmospheric temperature, liquid water content, and median volumetric diameter). Results indicated that this method of evaluating rotorcraft icing is both feasible and useful.
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Ghaderi, A. A., A. Mohammadzadeh, and M. N. Bahrami. "Optimum Design of Damped Vibration Absorber for Rotationally Periodic Structures." Journal of Mechanics 32, no. 4 (April 14, 2016): 381–90. http://dx.doi.org/10.1017/jmech.2016.20.
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AbstractIn this study, a damped centrifugally driven order-tuned vibration absorber designed for vibration reduction in rotating flexible structures, bladed disk assemblies and blisk such as turbine blades, compressor and fan blades, pump and helicopter rotor blades etc. during steady operation with constant speed and under engine order excitation (e.o excitation). Effect of mistuning is disregarded. System is assumed with fully cyclic symmetry. The disk is imposed as being rigid. Elastic behavior for blades is supposed. A model with two degree of freedom is extracted for the blades. Each blade is fitted with nominally identical damped order-tuned vibration absorber that is moved in a circular path. Aerodynamic damping and coupling effects between the blades are considered. Optimal values of parameters of the absorber, to suppress blade vibration especially in resonance condition, are derived by Genetic Algorithm (GA) and MATLAB software. H2 optimization criterion is used. It is observed that with the deviation of each parameter from the optimal condition, the system response is moved away from the ideal design situation and all of the absorbers’ design parameters have definite effects on the system frequency response and on the dissipated energy during vibration. Therefore, ignorance of the effect of one of those parameters (which was happened in literature) affected the system response completely. Literature is reviewed and validity of the results is confirmed.
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Degu, Yonas Mitik, and Derbew Alebel. "Design of Composite Gyrocopter Main Rotor Blade Involving Rib and Spar Elements." Journal of Engineering, Project, and Production Management 9, no. 2 (July 1, 2019): 97–106. http://dx.doi.org/10.2478/jeppm-2019-0011.
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Abstract Gyrocopter or gyroplane is a type of rotorcraft that uses an unpowered main rotor in free autorotation to develop lift. Gyrocopter rotor blades have smaller cord length and longer span compared to helicopters blades. National Advisory Committee for Aeronautics (NACA) 8-H-12 gyrocopter rotor blade profile, unsymmetrical airfoil sections were used for this research. An attempt has been made in this work to investigate the effect of ribs and spar elements in response to applied load. Three possible modeling alternatives were studied to predict the actual induced stress and deformation of the blade: Model I is by considering the blade shell part only, Model II is blade shell with 25 numbers of ribs and without the spar element and Model III is blade shell with 25 numbers of ribs and with spar element. The rotor blade was sized based on single seat open frame and high-wind-start gyrocopter. Structural static analysis has been carried out to evaluate the strength of composite rotor blade using ANSYS Workbench 15. The results show that among these three proposed models; Model III had registered minimum Von Mises stress and deformation. Also the result reveals that by considering ribs and spar element during analysis of gyrocopter blade is crucial because, it will help to know the actual induced stress and deformation. The predicted value of induced stress and deformation is closer to the actual values will help the designer not to overdesign the parts. Consequently, the main drawbacks related to overdesign increase in weight and cost will be minimized; thereby the product operational efficiency will be improved.
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Гребеников, А. Г., Ю. В. Дьяченко, В. В. Коллеров, И. В. Малков, Н. И. Москаленко, and В. А. Урбанович. "КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ НЕСУЧИХ ПОВЕРХОНЬ ВЕРТОЛЬОТА З ПОЛІМЕРНИХ КОМПОЗИЦІЙНИХ МА-ТЕРІАЛІВ." Open Information and Computer Integrated Technologies, no. 84 (July 2, 2019): 4–49. http://dx.doi.org/10.32620/oikit.2019.84.01.
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The analysis of both foreign and domestic experience in the use of polymer composite materials in the structures of the lifting surfaces of a helicopter (blades, wing, stabilizer, fin), as well as the technological features of the manufacture of such structures is performed. The design and technological and operational advantages and disadvantages of composite blades compared to all-metal blades are noted. The load-carrying structures of the composite main rotor blades of a helicopter, as well as the schemes of special joints of the MR blade and the polymer composite materials package are considered. The route scheme for manufacturing of the composite blade of a helicopter is presented. The technological features of manufacturing the composite spar of a blade are analyzed by the methods of lay-up and winding-on. The scheme and route technology for manufacturing the tail section of a blade, including the scheme of lay-up and molding of composite covers and ribs, are presented. The efficiency of the equipment for automatic cutting of the roll prepreg and manual lay-up of the prepreg layers with the help of a laser projector is noted. The technological tasks of special software for lay-up CNC equipment are given. The technological transitions of the general assembly-bonding of a helicopter composite blade in the assembly jig are presented. Recommendations are given on the method of manufacturing a monoblock lifting surfaces of type of a wing, tail pylon and helicopter stabilizer from polymer composite materials using automated winding-on. A scheme of surface reinforcement is proposed. It allows to obtain a variable wall thickness from the root rib to the end rib. The trajectories of movement of the working bodies of a three-coordinate CNC winding machine for their implementation are determined. A variant of a computer simulation of the stages of lay-up of a reinforcing tape on a technological mandrel is shown. The technology of manufacturing a low aspect wing made of polymer composite materials by the method of automated winding is presented.
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Shahmiri, Farid. "Twin-rotor hover performance examination using overlap tests." Aircraft Engineering and Aerospace Technology 89, no. 1 (January 3, 2017): 155–63. http://dx.doi.org/10.1108/aeat-02-2015-0032.
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Purpose The aim of this paper was to experimentally examine twin-rotor hover performance for different rotor overlap ratios at practical rotor loading. Design/methodology/approach The methodology was formed based on data measurements for a designed twin-rotor test model and development of hover performance mathematical models. Thus, measurements were made using a central composite test plan, and then mathematical models for thrust power required power loading (PL) and figure of merit (FM) as functions of collective pitch tip speed; rotor overlap ratio was obtained. In the present paper, the test model consisted of two three-bladed rotors with a diameter of 220 mm and a blade aspect ratio of 16.05. The blades were of a rectangular planform with NACA 0012 cross sections and had no twist or taper. The model was built such that the rear rotor was fixed on the fuselage, and the front rotor could move longitudinally for tests up to about 40 per cent overlap ratio in hover. Findings The best hover aerodynamic efficiency (maximum PL of 14.6 kg/kW) was achieved for non-overlapped rotors at a low value of disc loading (DL) and also at FM of 0.6 at that DL. This result was in agreement with blade element momentum theory predictions. Practical implications Results for the twin-rotor test model can be generalized for actual tandem helicopters through the Reynolds number transformation technique and also some modifications. Originality/value Design and construction of the twin-rotor test model and experimental measurements of hover performance based on an optimal test plan were performed for the first time.
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Kostic, Ivan. "Some practical issues in the computational design of airfoils for the helicopter main rotor blades." Theoretical and Applied Mechanics 31, no. 3-4 (2004): 281–315. http://dx.doi.org/10.2298/tam0404281k.
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Very important requirement for the helicopter rotor airfoils is zero, or nearly zero moment coefficient about the aerodynamic center. Unlike the old technologies used for metal blades, modern production involving application of plastic composites has imposed the necessity of adding a flat tab extension to the blade trailing edge, thus changing the original airfoil shape. Using computer program TRANPRO, the author has developed and verified an algorithm for numerical analysis in this design stage, applied it on asymmetrical reflex camber airfoils, determined the influence of angular tab positioning on the moment coefficient value and redesigned some existing airfoils to include properly positioned tabs that satisfy very low moment coefficient requirement. .
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Stalewski, Wienczyslaw, and Katarzyna Surmacz. "Investigations of the vortex ring state on a helicopter main rotor using the URANS solver." Aircraft Engineering and Aerospace Technology 92, no. 9 (April 10, 2020): 1327–37. http://dx.doi.org/10.1108/aeat-12-2019-0264.
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Purpose This paper aims to present the novel methodology of computational simulation of a helicopter flight, developed especially to investigate the vortex ring state (VRS) – a dangerous phenomenon that may occur in helicopter vertical or steep descent. Therefore, the methodology has to enable modelling of fast manoeuvres of a helicopter such as the entrance in and safe escape from the VRS. The additional purpose of the paper is to discuss the results of conducted simulations of such manoeuvres. Design/methodology/approach The developed methodology joins several methods of computational fluid dynamics and flight dynamic. The approach consists of calculation of aerodynamic forces acting on rotorcraft, by solution of the unsteady Reynold-averaged Navier–Stokes (URANS) equations using the finite volume method. In parallel, the equations of motion of the helicopter and the fluid–structure-interaction equations are solved. To reduce computational costs, the flow effects caused by rotating blades are modelled using a simplified approach based on the virtual blade model. Findings The developed methodology of computational simulation of fast manoeuvres of a helicopter may be a valuable and reliable tool, useful when investigating the VRS. The presented results of conducted simulations of helicopter manoeuvres qualitatively comply with both the results of known experimental studies and flight tests. Research limitations/implications The continuation of the presented research will primarily include quantitative validation of the developed methodology, with respect to well-documented flight tests of real helicopters. Practical implications The VRS is a very dangerous phenomenon that usually causes a sudden decrease of rotor thrust, an increase of the descent rate, deterioration of manoeuvrability and deficit of power. Because of this, it is difficult and risky to test the VRS during the real flight tests. Therefore, the reliable computer simulations performed using the developed methodology can significantly contribute to increase helicopter flight safety. Originality/value The paper presents the innovative and original methodology for simulating fast helicopter manoeuvres, distinguished by the original approach to flight control as well as the fact that the aerodynamic forces acting on the rotorcraft are calculated during the simulation based on the solution of URANS equations.