Milestones in Rotorcraft Aeromechanics

The subject of this paper is milestones in rotorcraft aeromechanics. Aeromechanics covers much of what the engineer needs: performance, loads, vibration, stability, flight dynamics, noise. These topics cover many of the key performance attributes, and many of the often-encountered problems in rotorcraft designs. A milestone is a critical achievement, a turning point, an event marking a significant change or stage in development. The milestones identified and discussed include the beginnings of aeromechanics with autogyro analysis, ground resonance, aeromechanics books, unsteady aerodynamics and airloads, nonuniform inflow and wakes, beams and dynamics, comprehensive analysis, computational fluid dynamics, and rotor airloads tests. The focus on milestones limits the scope of the history, but allows the author to acknowledge his choices for key steps in the development of the science and engineering of rotorcraft.

[1]  Yechiel Shulman.  Stability of a Flexible Helicopter Rotor Blade in Forward Flight , 1956 .

[2]  Kurt H. Hohenemser,et al.  Some Applications of the Method of Multiblade Coordinates , 1972 .

[3]  T T Chang.  A METHOD FOR PREDICTING THE TRIM CONSTANTS AND THE ROTOR-BLADE LOADINGS AND RESPONSES OF A SINGLE-ROTOR HELICOPTER , 1967 .

[4]  Maurice I. Young,et al.  A Theory of Rotor Blade Motion Stability in Powered Flight , 1964 .

[5]  R. A. Piziali,et al.  Method for the solution of the aeroelastic response problem for rotating wings , 1966 .

[6]  B. L. Blankenship,et al.  Rotorcraft Flight Simulation with Aeroelastic Rotor and Improved Aerodynamic Representation. Volume I. Engineer's Manual , 1974 .

[7]  Morris Morduchow.  A theoretical analysis of elastic vibrations of fixed-ended and hinged helicopter blades in hovering and vertical flight , 1950 .

[8]  M. V. Lowson,et al.  A theoretical study of helicopter rotor noise , 1969 .

[9]  Harold Hirsch.  The Contribution of Higher Mode Resonance to Helicopter Rotor-Blade Bending , 1953 .

[10]  J. Prieur,et al.  HHC aeroacoustic rotor tests in the German-Dutch wind tunnel: Improving physical understanding and prediction codes , 1996 .

[11]  Anton J. Landgrebe,et al.  An Analytical and Experimental Investigation of Helicopter Rotor Hover Performance and Wake Geometry Characteristics , 1971 .

[12]  R. H. Miller.  THEORETICAL DETERMINATION OF ROTOR BLADE HARMONIC AIRLOADS , 1964 .

[13]  R. T. Lytwyn,et al.  The Influence of Blade Flapping Restraint on the Dynamic Stability of Low Disk Loading Propeller-Rotors , 1967 .

[14]  Dewey H. Hodges,et al.  Nonlinear Equations for Bending of Rotating Beams with Application to Linear Flap-Lag Stability of Hingeless Rotors , 1973 .

[15]  F. X. Caradonna,et al.  Finite difference modeling of rotor flows including wake effects , 1984 .

[16]  Francis X. Caradonna,et al.  Numerical Calculation of Unsteady Transonic Potential Flow over Helicopter Rotor Blades , 1975 .

[17]  P. Dorato,et al.  State variables for engineers , 1967 .

[18]  Alfred Gessow.  Equations and procedures for numerically calculating the aerodynamic characteristics of lifting rotors , 1956 .

[19]  P. Likins,et al.  Analysis of structures with rotating, flexible substructures , 1987 .

[20]  J. P. Rabbott,et al.  TABULATED SIKORSKY CH-34 BLADE SURFACE PRESSURES MEASURED AT THE NASA/ AMES FULL SCALE WIND TUNNEL , 1966 .

[21]  D. Hodges.  A mixed variational formulation based on exact intrinsic equations for dynamics of moving beams , 1990 .

[22]  Emil F. Weiland.  Development And Test Of The BO 105 Rigid Rotor Helicopter , 1968 .

[23]  Wayne Johnson,et al.  Comparison of calculated and measured helicopter rotor lateral flapping angles , 1981 .

[24]  G. Horvay,et al.  Rotor blade flapping motion , 1947 .

[25]  Arnold M. Feingold,et al.  Theory of ground vibrations of a two-blade helicopter rotor on anisotropic flexible supports , 1947 .

[26]  Jean-Jacques Chattot,et al.  Calculation of three-dimensional unsteady transonic flows past helicopter blades , 1980 .

[27]  David A. Peters,et al.  Review of dynamic inflow modeling for rotorcraft flight dynamics , 1986 .

[28]  P. Tong,et al.  Dynamic Nonlinear Elastic Stability of Helicopter Rotor Blades in Hover and in Forward Flight , 1972 .

[29]  F. B. Gustafson.  History of NACA/NASA rotating-wing aircraft research, 1915-1970. III Cont'd , 1970 .

[30]  Anton J. Landgrebe,et al.  The Wake Geometry of a Hovering Helicopter Rotor and its Influence on Rotor Performance , 1972 .

[31]  John C. Houbolt,et al.  Differential equations of motion for combined flapwise bending, chordwise bending, and torsion of twisted nonuniform rotor blades , 1957 .

[32]  Franklin D. Harris,et al.  Articulated Rotor Blade Flapping Motion at Low Advance Ratio , 1972 .

[33]  Michael P. Scully.  APPROXIMATE SOLUTIONS FOR COMPUTING HELICOPTER HARMONIC AIRLOADS , 1965 .

[34]  R. T. Yntema,et al.  Simplified Procedures and Charts for the Rapid Estimation of Bending Frequencies of Rotating Beams , 1954 .

[35]  H. Glauert.  The Theory of the Autogyro , 1927 .

[36]  Dewey H. Hodges,et al.  Free-Vibration Analysis of Rotating Beams by a Variable-Order Finite-Element Method , 1981 .

[37]  J. P. Jones.  The Influence of the Wake on the Flutter and Vibration of Rotor Blades , 1958 .

[38]  R. P. Coleman.  Theory of self-excited mechanical oscillations of hinged rotor blades , 1943 .

[39]  Van Gaasbeek,et al.  Validation of the Rotorcraft Flight Simulation Program (C81) Using Operational Loads Survey Flight Test Data. , 1980 .

[40]  Kenneth B Amer.  Theory of Helicopter Damping in Pitch or Roll and a Comparison with Flight Measurements , 1950 .

[41]  J. Blachut,et al.  Conservative full-potential model for unsteady transonic rotor flows , 1987 .

[42]  Ames,et al.  System For Interdisciplinary Analysis - A Key To Improved Rotorcraft Design , 1979 .

[43]  R. H. Miller,et al.  On the Computation of Airloads Acting on Rotor Blades in Forward Flight , 1962 .

[44]  Berend G. van der Wall,et al.  Chimera simulations of multibladed rotors in high-speed forward flight with weak fluid-structure-coupling , 2005 .

[45]  D. K. Berrington.  Design and Development of the Westland Sea Lynx , 1974 .

[46]  J. P. Rabbott,et al.  A PRESENTATION OF MEASURED AND CALCULATED FULL-SCALE ROTOR BLADE AERODYNAMIC AND STRUCTURAL LOADS , 1966 .

[47]  Inderjit Chopra,et al.  Finite Element Analysis for Bearingless Rotor Blade Aeroelasticity , 1984 .

[48]  Charles A. Gates,et al.  Investigation of Helicopter Blade Flutter and Load Amplification Problems , 1957 .

[49]  R. M. Kufeld,et al.  UH-60A helicopter rotor airloads measured in flight , 1997, The Aeronautical Journal (1968).

[50]  R. H. Miller,et al.  Rotor blade harmonic air loading , 1964 .

[51]  R. Loewy.  A Two-Dimensional Approximation to the Unsteady Aerodynamics of Rotary Wings , 1957 .

[52]  Max M Munk.  Some Tables of the Factor of Apparent Additional Mass , 1924 .

[53]  W. Johnson,et al.  Application of a lifting-surface theory to the calculation of helicopter airloads , 1971 .

[54]  Mark Potsdam,et al.  Rotor Airloads Prediction Using Loose Aerodynamic/Structural Coupling , 2004 .

[55]  Inderjit Chopra,et al.  CFD/CSD Prediction of Rotor Vibratory Loads in High-Speed Flight , 2006 .

[56]  G. J. Sissingh.  Dynamics of Rotors Operating at High Advance Ratios , 1968 .

[57]  Franklin D. Harris.  Preliminary Study of Radial Flow Effects on Rotor Blades , 1966 .

[58]  C. H. Perisho,et al.  Analysis of the Stability of a Flexible Rotor Blade at High Advance Ratio , 1959 .

[59]  Wayne Johnson,et al.  Technology Drivers in the Development of CAMRAD II , 1999 .

[60]  P. Friedmann,et al.  Aeroelastic behavior of composite rotor blades with swept tips , 1992 .

[61]  F. X. Caradonna,et al.  The flow over a helicopter blade tip in the transonic regime , 1976 .

[62]  J. M. Duhon,et al.  Computer Flight Testing of Rotorcraft , 1965 .

[63]  Francis X. Caradonna,et al.  Subsonic and Transonic Potential Flow over Helicopter Rotor Blades , 1972 .

[64]  Jacques Valensi,et al.  Response of Rotor Lift to an Increase in Collective Pitch in the Case of Descending Flight, the Regime of the Rotor Being Near Autorotation , 1960 .

[65]  Dewey H. Hodges,et al.  Nonlinear analysis of a cantilever beam , 1988 .

[66]  Dewey H. Hodges,et al.  Nonlinear equations for dynamics of pretwisted beams undergoing small strains and large rotations , 1985 .

[67]  Wayne Johnson,et al.  A lifting surface solution for vortex induced airloads and its application to rotary wing airloads calculations. , 1971 .

[68]  Dewey H. Hodges,et al.  Linear Flap-Lag Dynamics of Hingeless Helicopter Rotor Blades in Hover , 1972 .

[69]  Roger Douglas Connor.  Wrecked Rotors: Understanding Rotorcraft Accidents, 1935-1945 , 2010 .

[70]  William G. Bousman,et al.  Aerodynamic Limitations of the UH-60A Rotor , 1996 .

[71]  D. Peters.  Hingeless rotor frequency response with unsteady inflow , 1974 .

[72]  S J Briczinski.  Validation of the Rotorcraft Flight Simulation Program (C81) for Articulated Rotor Helicopters through Correlation with Flight Data , 1976 .

[73]  A.R.S. Bramwell,et al.  The flapping behaviour of a helicopter rotor at high tip-speed ratios , 1965 .

[74]  Berend G. van der Wall,et al.  Progress in Weak Fluid-Structure-Coupling for Multibladed Rotors in High-Speed forward Flight , 2002 .

[75]  F. Micheli,et al.  Initial Results from the Higher Harmonic Control Aeroacoustic Rotor Test (HART) in the German-Dutch Wind Tunnel. , 1995 .

[76]  Peter F. Lorber,et al.  A Comprehensive Hover Test of the Airloads and Airflow of an Extensively Instrumented Model Helicopter Rotor , 1989 .

[77]  Dewey H. Hodges,et al.  Introduction to GRASP - General rotorcraft aeromechanical stability program - A modern approach to rotorcraft modeling , 1987 .

[78]  Paolo Mantegazza,et al.  A general purpose program for rotor blade dynamics , 1981 .

[79]  Paul J Carpenter,et al.  Effect of a Rapid Blade-Pitch Increase on the Thrust and Induced-Velocity Response of a Full-Scale Helicopter Rotor , 1953 .

[80]  Dewey H. Hodges,et al.  Stability of Hingeless Rotor Blades in Hover with Pitch-Link Flexibility , 1977 .

[81]  David A. Peters.  How Dynamic Inflow Survives in the Competitive World of Rotorcraft Aerodynamics , 2009 .

[82]  Alan Jones,et al.  Correlation of Puma airloads: Evaluation of CFD prediction methods , 1989 .

[83]  William G. Bousman,et al.  Flight Testing the UH-60A Airloads Aircraft , 1994 .

[84]  Edward C. Smith,et al.  Aeroelastic response, loads, and stability of a composite rotor in forward flight , 1993 .

[85]  William G. Bousman,et al.  An Experimental Investigation of the Effects of Aeroelastic Couplings on Aeromechanical Stability of a Hingeless Rotor Helicopter , 1981 .

[86]  Olivier A. Bauchau,et al.  Modeling rotorcraft dynamics with finite element multibody procedures , 2001 .

[87]  David A. Peters,et al.  Application of the Floquet Transition Matrix to Problems of Lifting Rotor Stability , 1971 .

[88]  Inderjit Chopra,et al.  Blade Response Calculations Using Three-Dimensional Aerodynamic Modeling , 1991 .

[89]  J. L. Cross,et al.  The NASA modern technology rotors program , 1986 .

[90]  Arnold M Feingold,et al.  Theory of Mechanical Oscillations of Rotors With Two Hinged Blades , 1943 .

[91]  M. Costes,et al.  A weak coupling method between the dynamics code HOST and the 3D unsteady Euler code WAVES , 2001 .

[92]  Van Gaasbeek,et al.  An Investigation of High-G Maneuvers of the AH-1G Helicopter , 1975 .

[93]  R. A. Piziali,et al.  An Improved Computational Model for Predicting the Unsteady Aerodynamic Loads of Rotor Blades , 1966 .

[94]  Gabriel Horvay,et al.  Stability of Rotor Blade Flapping Motion When the Hinges Are Tilted. Generalization of the "Rectangular Ripple" Method of Solution , 1947 .

[95]  Dewey H. Hodges,et al.  Nonlinear Composite Beam Theory , 2006 .

[96]  Frank A. Duwaldt,et al.  A METHOD FOR COMPUTING ROTARY WING AIRLOAD DISTRIBUTION IN FORWARD FLIGHT , 1962 .

[97]  Kurt H. Hohenemser,et al.  On The Dynamics Of Lifting Rotors With Thrust Or Tilting Moment Feedback Controls , 1969 .

[98]  Michael P. Scully.  A METHOD OF COMPUTING HELICOPTER VORTEX WAKE DISTORTION , 1967 .

[99]  M. Scully,et al.  Computation of helicopter rotor wake geometry and its influence on rotor harmonic airloads , 1975 .

[100]  M. E. Tauber,et al.  Computation of subsonic and transonic flow about lifting rotor blades , 1979 .

[101]  J. Grant,et al.  The prediction of supercritical pressure distributions on blade tips , 1978 .

[102]  Robert P Rabbott,et al.  Experimental Investigation of the Aerodynamic Loading on a Helicopter Rotor Blade in Forward Flight , 1956 .

[103]  Dewey H. Hodges,et al.  Stability of elastic bending and torsion of uniform cantilevered rotor blades in hover , 1973 .

[104]  R L Bennett,et al.  Application of Rotorcraft Flight Simulation Program (C81) to Predict Rotor Performance and Bending Moments for a Model Four-Bladed Articulated Rotor System , 1974 .

[105]  Peter F. Lorber,et al.  Aerodynamic Results of a Pressure-Instrumented Model Rotor Test at the DNW , 1991 .

[106]  By O. J. LowIs.  The Stability of Rotor Blade Flapping Motion at High Tip Speed Ratios , 1963 .

[107]  R. H. Prewitt.  Frequency and Vibration Problems of Rotors , 1940 .

[108]  William G. Bousman,et al.  A Qualitative Examination of Dynamic Stall from Flight Test Data , 1997 .

[109]  Inderjit Chopra,et al.  Review of Rotor Loads Prediction with the Emergence of Rotorcraft CFD , 2007 .

[110]  John B. Wheatley.  An aerodynamic analysis of the autogiro rotor with a comparison between calculated and experimental results , 1935 .

[111]  M. Isom.  Unsteady Subsonic and Transonic Potential Flow over Helicopter Rotor Blades , 1974 .

[112]  R. H. Miller,et al.  Helicopter Control and Stability in Hovering Flight , 1948 .

[113]  Manikandan Ramasamy,et al.  Flowfield Measurements to Understand Effect of Wake Behavior on Rotor Performance , 2010 .

[114]  D. H. Roberta. Hodges,et al.  Stability of elastic bending and torsion of uniform cantilever rotor blades in hover with variable structural coupling , 1976 .

[115]  Datta,et al.  Analysis Refinements for Prediction of Rotor Vibratory Loads in High-Speed Forward Flight , 2004 .

[116]  J. J. Corrigan,et al.  Copter 2000: The QTR And Beyond , 2001 .

[117]  John F. Ward,et al.  Helicopter Rotor Periodic Differential Pressures and Structural Response Measured in Transient and Steady-State Maneuvers , 1971 .

[118]  William G. Bousman,et al.  High Load Conditions Measured on a UH-60A in Maneuvering Flight , 1998 .

[119]  Wayne Johnson,et al.  Influence of unsteady aerodynamics on hingeless rotor ground resonance , 1982 .

[120]  W. H. Reed,et al.  Propeller-Nacelle Whirl Flutter , 1962 .

[121]  Keith W Harvey,et al.  Analytical Study of Helicopter Gust Response at High Forward Speeds , 1969 .

[122]  Peretz P. Friedmann,et al.  Aeroelastic Instabilities of Hingeless Helicopter Blades , 1973 .

[123]  G Sissingh.  Contribution to the Aerodynamics of Rotating-Wing Aircraft , 1939 .

[124]  C. W. Stammers,et al.  The Flutter of a Helicopter Rotor Blade in Forward Flight , 1970 .

[125]  R. Gray.  AN AERODYNAMIC ANALYSIS OF A SINGLEBLADED ROTOR IN HOVERING AND LOW- SPEED FORWARD FLIGHT AS DETERMINED FROM SMOKE STUDIES OF THE VORTICITY DISTRIBUTION IN THE WAKE , 1956 .

[126]  I. Chopra,et al.  Dynamic stability of a rotor blade using finite element analysis , 1981 .

[127]  William D Anderson,et al.  Application of an Interdisciplinary Rotary-Wing Aircraft Analysis to the Prediction of Helicopter Maneuver Loads , 1973 .

[128]  D. Peters,et al.  Effectiveness of Current Dynamic-Inflow Models in Hover and Forward Flight , 1986 .

[129]  R. H. Miller,et al.  Unsteady Air Loads on Helicopter Rotor Blades , 1964, The Journal of the Royal Aeronautical Society.

[130]  Frank A. Duwaldt,et al.  Computed Induced Velocity, Induced Drag, and Angle of Attack Distributions for a Two-Bladed Rotor , 1963 .

[131]  Hanno H. Heller,et al.  HHC Aeroacoustics Rotor Test at the DNW. - The Joint German/French/US HART Project - , 1994 .

[132]  W. R. Splettstoesser,et al.  Key Results from a Higher Harmonic Control Aeroacoustic Rotor Test (HART) , 1997 .

[133]  Roger C. Strawn,et al.  AN IMPROVED THREE-DIMENSIONAL AERODYNAMICS MODEL FOR HELICOPTER AIRLOADS PREDICTION , 1991 .

[134]  Kurt H. Hohenemser,et al.  Aeroelastic Instability of Torsionally Rigid Helicopter Blades , 1967 .

[135]  Hyeonsoo Yeo,et al.  Assessment of Comprehensive Analysis Calculation of Airloads on Helicopter Rotors , 2005 .

[136]  Todd R. Quackenbush,et al.  Computation of rotor aerodynamic loads in forward flight using a full-span free wake analysis , 1990 .

[137]  H. Huber,et al.  Effect of Torsion-Flap-Lag Coupling on Hingeless Rotor Stability , 1973 .

[138]  Roger C. Strawn,et al.  Prediction of unsteady transonic rotor loads with a full-potential rotor code , 1987 .

[139]  Earl H. Dowell,et al.  Nonlinear equations of motion for the elastic bending and torsion of twisted nonuniform rotor blades , 1974 .

[140]  Senor de la Cierva.  The Development of the Autogyro , 1926 .

[141]  William G. Bousman,et al.  Putting the Aero Back into Aeroelasticity , 1999 .

[142]  Roger Strawn,et al.  The prediction of transonic loading advancing helicopter rotors , 1986 .

[143]  James R. Hansen.  Enchanted Rendezvous: John C. Houbolt and the Genesis of the Lunar-Orbit Rendezvous Concept , 2012 .

[144]  Robert P. Coleman,et al.  Theory of self-excited mechanical oscillations of helicopter rotors with hinged blades , 1958 .

[145]  Walter Castles,et al.  A blade-element analysis for lifting rotors that is applicable for large inflow and blade angles and any reasonable blade geometry , 1952 .

[146]  Hyeonsoo Yeo,et al.  Prediction of Rotor Structural Loads with Comprehensive Analysis , 2008 .

[147]  F. X. Caradonna,et al.  Experimental and Analytical Studies of a Model Helicopter Rotor in Hover , 1980 .

[148]  Dewey H. Hodges,et al.  Analysis of structures with rotating, flexible substructures applied to rotorcraft aeroelasticity in GRASP. [General Rotorcraft Aeromechanical Stability Program] , 1989 .

[149]  W. Kinner,et al.  Die kreisförmige Tragfläche auf potentialtheoretischer Grundlage , 1937 .

[150]  John L. McCloud,et al.  Considerations of the stopped rotor V/STOL concept. , 1968 .

[151]  Kurt H. Hohenemser,et al.  Identification of state variables and dynamic inflow from rotor model dynamic tests , 1977 .

[152]  Norman D. Ham,et al.  EXPERIMENTAL AND THEORETICAL ANALYSIS OF HELICOPTER ROTOR HUB VIBRATORY FORCES , 1959 .

[153]  Inderjit Chopra,et al.  Coupled CFD/CSD prediction of rotor aerodynamic and structural dynamic loads for three critical flight conditions , 2005 .

[154]  Peretz P. Friedmann,et al.  Some conclusions regarding the aeroelastic stability of hingeless helicopter blades in hover and in forward flight , 1973 .

[155]  Juan De La Cierva.  New Developments of the Autogiro , 1935 .

[156]  James A Staley,et al.  Validation of Rotorcraft Flight Simulation Program through Correlation with Flight Data for Soft-in-Plane Hingeless Rotors , 1976 .

[157]  O. Bauchau,et al.  A Multibody Formulation for Helicopter Structural Dynamic Analysis , 1993 .

[158]  M. Joglekar,et al.  An Actuator-Disc Analysis of Helicopter Wake Geometry and the Corresponding Blade Response , 1970 .

[159]  K. H. Hohenemser,et al.  The method of multiblade coordinates in the linear analysis of lifting rotor dynamic stability and gust response at high advance ratio , 1971 .

[160]  Masahiro Yasue.  Gust response and its alleviation for a hingeless helicopter rotor in cruising flight. , 1977 .

[161]  L. Tuckerman.  Inertia Factors of Ellipsoids for Use in Airship Design , .

[162]  F. Micheli,et al.  Higher harmonic Control Aeroacustic Rotor Test (HART) - Test Documentation and Representative Results , 1996 .

[163]  W. Johnson,et al.  Recent developments in rotary-wing aerodynamic theory , 1986 .

[164]  Peretz P. Friedmann,et al.  APPLICATION OF THE FINITE ELEMENT METHOD TO ROTARY-WING AEROELASTICITY. , 1980 .

[165]  H. L. Kelley,et al.  Comparison of Flight Measured Helicopter Rotor Blade Chordwise Pressure Distributions and Two-Dimensional Airfoil Characteristics , 1963 .

[166]  Thomas R. Norman,et al.  Full-Scale Wind Tunnel Test Of A UH-60 Individual Blade Control System For Performance Improvement And Vibration, Loads, And Noise Control , 2009 .

[167]  P. Tong,et al.  Non-linear flap-lag dynamics of hingeless helicopter blades in hover and in forward flight , 1973 .

[168]  Kurt H. Hohenemser,et al.  Model tests on unsteady rotor wake effects. , 1973 .

[169]  Franklin D. Harris,et al.  Rotor Performance at High Advance Ratio: Theory versus Test , 2008 .

[170]  David A. Peters,et al.  Theoretical prediction of dynamic inflow derivatives , 1980 .

[171]  J Scheiman,et al.  A TABULATION OF HELICOPTER ROTOR-BLADE DIFFERENTIAL PRESSURES, STRESSES, AND MOTIONS AS MEASURED IN FLIGHT , 1964 .

[172]  Richard Gabel,et al.  Specialists Meeting on Helicopter Rotor Loads Prediction Methods , 1973 .

[173]  Almer D Crim,et al.  An extension of lifting rotor theory to cover operation at large angles of attack and high inflow conditions , 1952 .

[174]  K. W. Harvey,et al.  A Digital Analysis for Helicopter Performance and Rotor Blade Bending Moments , 1962 .

[175]  David A. Peters,et al.  On the nonlinear deformation geometry of Euler-Bernoulli beams. [rotary wings] , 1980 .

[176]  Henry Parkus,et al.  The Disturbed Flapping Motion of Helicopter Rotor Blades , 1948 .

[177]  P Y Hsieh.  Rotorcraft Flight Simulation Computer Program C81 with Datamap Interface, Volume 2. Programmer's Manual , 1981 .

[178]  R. H. Miller,et al.  Helicopter Blade Vibration and Flutter , 1956 .

[179]  Kurt H. Hohenemser,et al.  An unsteady wake model for a hingeless rotor , 1973 .

[180]  M. L. Deutsch.  Ground Vibrations of Helicopters , 1946 .

[181]  R. E. Hansford,et al.  Torsion-Flap-Lag Coupling on Helicopter Rotor Blades , 1973 .

[182]  F J Bailey.  A simplified theoretical method of determining the characteristics of a lifting rotor in forward flight , 1941 .

[183]  Berend G. van der Wall,et al.  The HART-II Test: Rotor Wakes and Aeroacoustics with Higher-Harmonic Pitch Control (HHC) Inputs - The Joint German/French/Dutch/US Project , 2002 .

[184]  Wayne Johnson,et al.  A General Free Wake Geometry Calculation For Wings and Rotors , 1995 .

[185]  H. Daughaday,et al.  An Approach To The Determination Of Higher Harmonic Rotor Blade Stresses , 1953 .

[186]  James L. Tangler,et al.  A Prescribed Wake Lifting Surface Hover Performance Analysis , 1977 .

[187]  Markus Raffel,et al.  The HART II Test in the LLF of the DNW - a Major Step towards Rotor Wake Understanding , 2002 .

[188]  F. K. Straub,et al.  A Galerkin type finite element method for rotary-wing aeroelasticity in hover and forward flight , 1980 .

[189]  R. Gray.  Vortex modeling for rotor aerodynamics - The 1991 Alexander A. Nikolsky Lecture , 1992 .

[190]  Atcom,et al.  Aerodynamic and Numerical Issues for Coupling CFD into Comprehensive Rotorcraft Analysis , 1997 .

[191]  H. Glauert.  A GENERAL THEORY OF THE AUTOGYRO , 2022 .

[192]  Dale M Pitt,et al.  Rotor dynamic inflow derivatives and time constants from various inflow models , 1980 .

[193]  W. R. Johnson,et al.  The Prediction of Transonic Flows on an Advancing Rotor , 1986 .

[194]  Alfred Gessow,et al.  Aerodynamics of the Helicopter , 1981 .

[195]  Almer D Crim,et al.  A method for studying the transient blade-flapping behavior of lifting rotors at extreme operating conditions , 1955 .

[196]  David A. Peters,et al.  Hingeless Helicopter Rotor Response with Nonuniform Inflow and Elastic Blade Bending , 1972 .

[197]  H. Glauert.  The elements of aerofoil and airscrew theory , 1926 .

[198]  Dewey H. Hodges,et al.  Nonlinear Equations of Motion for Cantilever Rotor Blades in Hover with Pitch Link Flexibility, Twist, Precone, Droop, Sweep, Torque Offset, and Blade Root Offset , 1976 .