Table of Contents
Preface.....................................................................v
Acknowledgments ................................................vii
Chapter 1
Introduction to the Helicopter ............................1-1
Introduction ....................................................................1-1
Turbine Age ...................................................................1-2
Uses ................................................................................1-3
Rotor System ..................................................................1-3
Rotor Configurations ..................................................1-4
Tandem Rotor ........................................................1-4
Coaxial Rotors .......................................................1-4
Intermeshing Rotors ................................................1-4
Tail Rotor ...................................................................1-5
Controlling Flight...........................................................1-5
Cyclic ........................................................................1-5
Collective ...................................................................1-5
Antitorque Pedals .......................................................1-6
Throttle ......................................................................1-6
Flight Conditions ...........................................................1-6
Chapter Summary ..........................................................1-7
Chapter 2
Aerodynamics of Flight .......................................2-1
Introduction ....................................................................2-1
Forces Acting on the Aircraft ........................................2-2
Lift ..............................................................................2-3
Bernoulli’s Principle ...............................................2-3
Venturi Flow ...........................................................2-4
Newton’s Third Law of Motion ..............................2-5
Weight ........................................................................2-5
Thrust .........................................................................2-6
Drag ............................................................................2-6
Profile Drag ............................................................2-6
Induced Drag ..........................................................2-7
Parasite Drag ...........................................................2-7
Total Drag ...............................................................2-7
Airfoil ............................................................................2-7
Airfoil Terminology and Definitions .........................2-7
Airfoil Types ..............................................................2-8
Symmetrical Airfoil ................................................2-8
Nonsymmetrical Airfoil (Cambered) ......................2-8
Blade Twist ...............................................................2-9
Rotor Blade and Hub Definitions ...........................2-9
Airflow and Reactions in the Rotor Disk .......................2-9
Relative Wind .............................................................2-9
Rotational Relative Wind (Tip-Path Plane)................2-9
Resultant Relative Wind ...........................................2-11
Induced Flow (Downwash) ..................................2-11
Rotor Blade Angles ..................................................2-12
Angle of Incidence ................................................2-12
Angle of Attack .....................................................2-13
Powered Flight .............................................................2-14
Hovering Flight ............................................................2-14
Translating Tendency (Drift)....................................2-15
Pendular Action ........................................................2-15
Coning ......................................................................2-16
Coriolis Effect (Law of Conservation of Angular
Momentum) .............................................................2-16
Gyroscopic Precession .............................................2-17
Vertical Flight ..............................................................2-17
Forward Flight .............................................................2-17
Airflow in Forward Flight .......................................2-19
Advancing Blade .................................................2-19
Retreating Blade ..................................................2-19
Dissymmetry of Lift .............................................2-20
Translational Lift ......................................................2-21
Effective Translational Lift (ETL) ........................2-22
Translational Thrust ..............................................2-22
Induced Flow ............................................................2-23
Transverse Flow Effect ............................................2-23
Sideward Flight ............................................................2-23
Rearward Flight ...........................................................2-24
Turning Flight ..............................................................2-24
Autorotation .................................................................2-25
Vertical Autorotation ................................................2-25
Autorotation (Forward Flight) ..................................2-26
Chapter Summary ........................................................2-26
Chapter 3
Helicopter Flight Controls ..................................3-1
Introduction ....................................................................3-1
Collective Pitch Control .................................................3-2
Throttle Control .............................................................3-2
Governor/Correlator ......................................................3-2
Cyclic Pitch Control .......................................................3-3
Antitorque Pedals ...........................................................3-4
Heading Control .........................................................3-4
Chapter Summary ..........................................................3-5