Helicopters calculation and design
HELICOPTERS CALCULATION AND DESIGNBY M. L. MIL', A. V. NEKRASOV, A. S. BRAVERMAN, L. N. GRODKO, AND M. A. LEYKAND
"Mashinostroyeniye" Publishing House, Moscow, 1966
NASA TECHNICAL TRANSLATION
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION, WASHINGTON, 1967
DOWNLOAD OLD AERONAUTICS BOOKS:
Helicopters calculation and design - Volume I
Helicopters calculation and design - Volume II
The work "Helicopters (Calculation and Design)" is published in three volumes
Vol.I - Aerodynamics;
Vol.II - Vibrations and Dynamic Strength;
Vol.III - Design.
ANNOTATION
The first volume is devoted to ways of developing helicopters, the basic principles of their design, and the position occupied by helicopters among other means of aviation not requiring airfields. Various theories of rotors and corresponding methods of determining their aerodynamic characteristics are presented: the classical theory of a rotor with hinged blades in the general case of curvilinear flight of the helicopter; the momentum theory of an ideal rotor and its application to the energy method of calculation; the classical theory when using methods of numerical quadrature; the vortex theory and methods of experimental determination of rotor performance in flight tests and in wind tunnels. Various methods of aerodynamic calculation of a helicopter and the theory of blade flutter are presented in detail. This volume gives an account of methods of calculating flutter in hovering and in forward flight. Particular attention is devoted to consideration of friction in the axial hinges of the hub and to the transfer of blade vibrations through the automatic pitch control mechanism. Experimental investigations of flutter are described.
The book is intended for engineers of design offices, scientific workers, graduate students, and teachers of higher institutes of learning. It might be useful to engineers of helicopter manufacturers and to students for furthering their knowledge of the aerodynamics and mechanical strength of helicopters. Mary sections of the book will be a useful tool also to flight and technical staffs of helicopter flight units.
PREFACE
The present book generalizes the experience of the scientific work and practical design activity of engineers of one of the Soviet teams working on the development of helicopters.
Twenty years ago, when the team had just set out on their work, everything in this field seemed to have been already long discovered and in-vented.
Those to whom belongs credit for the original ideas and designs of rotary-wing aircraft - Leonardo da Vinci, M.V.Lomonosov, M .Ye . Zhtikovskiy (Joukowski), B.N.Yuryev, and others - had long ago proposed almost all of the existing designs of helicopters. Designers, scientists, and inventors in various countries built dozens of helicopter models which successfully rose into the air. However, not one of these rotocraft was suitable for practical use, large-scale production, or regular service.
A very difficult problem that required considerable and tedious work remained unsolved, namely, the problem of developing helicopters which would find practical use in everyday life.
To solve this problem we had at our disposal an important scientific basis in the form of classical works, the studies of the Central Aero-hydrodynamic Institute (TsAGi), and of foreign scientists. However, testing of each new aircraft confronted design engineers with new acute problems and forced them to work out many theoretical problems to find the proper method of solving specific design problems.
This volume discusses the basic problems of the theory, calculation, and design of helicopters worked out by the team and representing the vital interests of its design activity.
The fact that some of the authors had occasion to participate in applying the classical rotor theory to the calculation and design of the first autogiros, in the original experimental work on models and on full-scale rotors in wind tunnels, in developing methods of aerodynamic calculation of helicopters, and then - for more than 15 years - in designing an entire family of helicopters of the same configuration in all weight classes, offers an opportunity to elucidate the basic problems of the theory and calculation of helicopters that have been checked out by practice.
As early as 194S there was not a single helicopter in service in our country. Now thousands of such machines created by various design teams assist people in many areas of their life and activity.
Engineers and designers working on the design or construction of helicopters, pilots and technicians, students of air academies who are studying or are interested in helicopters will find useful information in this book.
Engineering, especially aircraft engineering, is rapidly becoming obsolete. However, it is hoped that the general methods of approach to the development of a new type of aircraft, as presented in this book, will outlive today's helicopter models.
The book is intended for engineers of design offices, scientific workers, graduate students, and teachers of higher institutes of learning. It might be useful to engineers of helicopter manufacturers and to students for furthering their knowledge of the aerodynamics and mechanical strength of helicopters. Mary sections of the book will be a useful tool also to flight and technical staffs of helicopter flight units.
PREFACE
The present book generalizes the experience of the scientific work and practical design activity of engineers of one of the Soviet teams working on the development of helicopters.
Twenty years ago, when the team had just set out on their work, everything in this field seemed to have been already long discovered and in-vented.
Those to whom belongs credit for the original ideas and designs of rotary-wing aircraft - Leonardo da Vinci, M.V.Lomonosov, M .Ye . Zhtikovskiy (Joukowski), B.N.Yuryev, and others - had long ago proposed almost all of the existing designs of helicopters. Designers, scientists, and inventors in various countries built dozens of helicopter models which successfully rose into the air. However, not one of these rotocraft was suitable for practical use, large-scale production, or regular service.
A very difficult problem that required considerable and tedious work remained unsolved, namely, the problem of developing helicopters which would find practical use in everyday life.
To solve this problem we had at our disposal an important scientific basis in the form of classical works, the studies of the Central Aero-hydrodynamic Institute (TsAGi), and of foreign scientists. However, testing of each new aircraft confronted design engineers with new acute problems and forced them to work out many theoretical problems to find the proper method of solving specific design problems.
This volume discusses the basic problems of the theory, calculation, and design of helicopters worked out by the team and representing the vital interests of its design activity.
The fact that some of the authors had occasion to participate in applying the classical rotor theory to the calculation and design of the first autogiros, in the original experimental work on models and on full-scale rotors in wind tunnels, in developing methods of aerodynamic calculation of helicopters, and then - for more than 15 years - in designing an entire family of helicopters of the same configuration in all weight classes, offers an opportunity to elucidate the basic problems of the theory and calculation of helicopters that have been checked out by practice.
As early as 194S there was not a single helicopter in service in our country. Now thousands of such machines created by various design teams assist people in many areas of their life and activity.
Engineers and designers working on the design or construction of helicopters, pilots and technicians, students of air academies who are studying or are interested in helicopters will find useful information in this book.
Engineering, especially aircraft engineering, is rapidly becoming obsolete. However, it is hoped that the general methods of approach to the development of a new type of aircraft, as presented in this book, will outlive today's helicopter models.
CONTENTS (VOLUME I)
EVOLUTION HISTORY OF HELICOPTERS AND BASIC DESIGN PRINCIPLES
- Evolution of the Helicopter Industry
- The Helicopter Compared to Vertical Takeoff and Landing and Short Takeoff and Landing Aircraft
- Basic Principles of Design
ROTOR AERODYNAMICS
- Development of Rotor Theory and Methods of Experimental Determination of its Characteristics
- Classical Theory of a Rotor with Hinged Blade Attachment; General Case; Curvilinear Motion
- Rotor Theory in Curvilinear Motion
- Rotor Flapping in Curvilinear Motion of the Rotor Axis at Variable Angular Velocity
- Characteristics of Rotor Aerodynamics Determined by Hinged Blade Attachment
- Method of Calculating the Aerodynamic Characteristics of a Rotor for Azimuthal Variation of Blade Pitch
- Momentum Theory of Rotor
- Classical Rotor Theory. Method of Numerical Integration
- Vortex Theory of Rotor
- Vortex Theory of Wang Shi-Tsun
- Vortex Theory of V. E. Baskin
- Experimental Determination of Aerodynamic Characteristics of a Rotor
- Performance and Propulsive Efficiency Coefficient of a Rotor
- Calculation of Rotor Characteristics in Hovering and Vertical Ascent (Momentum Theory of Propellers)
AERODYNAMIC DESIGN OF A HELICOPTER
- Basic Equations for Aerodynamic Design of a Helicopter
- Aerodynamic Helicopter Design by the Mil'-Yaroshenko Method
- General Method of Aerodynamic Design for Rotary Wing Aircraft
- Aerodynamic Design of a Helicopter Based on Concepts of Rotor Performance and Efficiency
- Aerodynamic Calculation of a Helicopter by the Power Method
ROTOR FLUTTER
- Basic Assumptions and Characteristics of an Approach to Flutter Calculation
- Flapping Flutter of an Isolated Blade with Axial Flow past the Rotor
- Consideration of Friction Forces during Flutter
- Rotor Flutter with Consideration of Coupling of Blade Vibrations through the Automatic Pitch Control
- Flapping Flutter of a Rotor in Forward Flight
- Calculation of Flutter with Consideration of Bending and Torsion of the Blade
- General Method of Calculation of Flutter and Bending Stresses in the Rotor Blade during Flight
- Experimental Investigations of Flutter
CONTENTS (VOLUME II)
ELASTIC VIBRATIONS AND BLADE STRENGTH
- Problems of Calculation, Basic Assumptions, and Derivation of Differential Equations of Blade Bending Deformations
- Free Vibrations of the Blade of a Nonrotating Rotor
- Approximate Method of Determining the Natural Blade Vibration Frequencies in a Centrifugal Force Field
- Calculation of Natural Blade Vibration Modes and Frequencies in a Centrifugal Force Field
- Torsional Vibrations of a Blade
- Combined Flexural and Torsional Blade Vibrations
- Forced Blade Vibrations
- Calculation of Bending Stresses in a Blade at Low and Moderate Flying Speeds
- Calculation of Blade Bending Stresses, with Consideration of the Nonlinear Dependence of Aerodynamic Coefficients on Profile Angle of Attack and Mach Number
- Calculation of Flexural Vibrations with Direct
- Determination of the Paths of Motion of Points of the Blade
- Fatigue Strength and Blade life
HELICOPTER VIBRATIONS
- Forces Causing Helicopter Vibrations
- Flexural Vibrations of the Fuselage as an Elastic Beam
- Vibration Analysis with Consideration of Fuselage Characteristics
- Combined Vibrations of the System Fuselage Rotor
GROUND RESONANCE
- Stability of Rotor on an Elastic Base
- Lateral Vibrations of a Single-Rotor Helicopter
- Characteristics of Damping of landing Gear and Blade. Influence on Ground Resonance
- Ground Resonance of a Helicopter during Ground Run
- Ground Resonance of Helicopters of Other Configurations
- Selection of Basic Parameters of Landing Gear and Blade Dampers. Design Recommendations
THEORETICAL PRINCIPIES OF CALCULATING BEARINGS OF MAIN HELICOPTER COMPONENTS
- Equations of Static Equilibrium of Radial and Radial- Thrust Ball Bearings under Combined Load
- Calculation of Radial and Radial-Thrust Ball Bearings under Combined loads, for Absence of
- Misalignment of the Races
- Certain Problems in Calculating Radial-Thrust Ball Bearings -with Consideration of Misalignment of their Races under Load
- Calculation of Tapered Roller Bearings under Combined Loads
- Calculation of Vibrating Bearings
- Theory and Selection of Basic Parameters of Thrust Bearings with "Slewed" Rollers
DOWNLOAD OLD AERONAUTICS BOOKS:
Helicopters calculation and design - Volume I
Helicopters calculation and design - Volume II
