Helicopter Engineering Design Handbook Part One

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Helicopter Engineering Design Handbook Part One

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Helicopter Engineering Design Handbook Part One

FOREWORD

The Helicopter Engineering Handbook forms a part of the Engineering Design.

This volume, Preliminary Design, is Part One of a three-part Engineering Design Handbook titled Helicopter Engineering. design, Qualification Assurance, this part is intended to set forth explicit design standards for Army helicopters, to establish qualification requirements, and to provide technical guidance to helicopter designers in both the industry and within the Army.

This volume, discusses the characteristics and subsystems which must be considered during preliminary design of a helicopter. Additionally, possible design problems encountered during helicopter design are discussed and possible solutions suggested. The volume is divided into chapters and is organized as described in Chapter , the introduction to the volume.

Volue two deals with the evolution of the vehicle from an approved preliminary design configuration. As a result of this phase, the design must provide sufficient detail to permit construction and qualification of the helicopter in compliance with the approved detail specification and other requirements.

The third volume of the handbook, AMCP - , defines the requirements for airworthiness qualification of the helicopter and for demonstration of contract compli ance. The test procedures used by the Army in the performance of those additional tests required by the Airworthiness Qualification Program to be performed by the Army also are described.

ENGINEERING DESIGN HANDBOOK

HELICOPTER E GINEERING, PART ONE
PRELIMINARY DESIGN
TABLE OF CONTENTS
LIST OF ILLUSTRATIONS
LIST OF TABLES
FOREWORD
PREFACE

CHAPTER ONE
INTRODUCTION

CHAPTER TWO
MISSION EFFECTIVENESS
INTRODUCTION
MILITARY SYSTEM REQUIREMENTS AND MISSION EFFECTIVENESS
MILITARY SYSTEM REQUIREMENTS
Operations Research (OR)
Budgetary Considerations
DESIGN CYCLE
MISSION-EFFECTIVENESS EQUATION
Operational Factors
Economic Factor
OPERATIONAL FACTOR ANALYSIS
MISSION READINESS
Mission Capability (MC)
Availability
Reliability
Maintainability
SURVIVAP'UTY
PERFORM NCE
Performance Requirements
Performance Effectiveness
ECONOMIC ANALYSIS
GENERAL
ELEMENTS OF ECONOMIC ANALYSIS
FORMS OF CRITERIA
COST ANALYSIS
Cost Concepts .
Life Cycle Cost
Incremental Cost
Real Resource Utilization
Joint Costs
Other Cost Concepts
Cost Estimation
Data Development
CER Display Formats
CER Derivation
Use of CERs
SIMULATION MODELING: AN EXAMPLE
LIST OF SYMBOLS
REFERENCES

CHAPTER THREE
PERFORMANCE
INTRODUCTION
WORKING STATES OF A ROTOR
POWER REQUIRED FOR LEVEL FLIGHT
AERODYNAMICS
BASIC ANALYTICAL METHODS
Hovering Flight
Momentum Theory
Figure of Merit
Blade Element Theory
Tip Loss Factor
Vortex Theory — Three-dimensional Considerations
Theoretical Three-dimensional Prediction Method
Empirical Prediction Method
Ground Effect
Vertical Drag/Thrust Recovery
Power Train Effects
Forward Flight
Energy Methods
Induced Power
Profile Power
Parasite Power
Blade Element Theory
Wheatley Method
Iterative Procedure
Blade Stall
Numerical Methods
Graphical Method-NASA Charts
Radial Flow Corrections
Tandem-rotor Interference
Fixed Aerodynamic Surfaces
COMPOUND CONFIGURATIONS
Speed Capability of Helicopters
Preliminary Design Considerations
Selection of Configuration Parameters
Rotor
Auxiliary Propulsion
Torque Balancing and Directional Control
Compound Helicopter Performance
Wing/Rotor Lift Sharing
Calculating Procedure for Power Required Autorot ion of a Compound Helicopter .
WIND TUN MEL TESTING
Objectives
Support of a Project
Airframe Drag and Stability Studies
Powered Models
Dynamic Models
Special Models
Two-dimensional Airfoil Tests
Testing of Actual Hardware
Model Design Considerations
Models Without Rotors
Models With Rotors
Rotor Design
Rotor Control Systems
Rotor Power Supply
Instrumentation
Test Procedures
Data Reduction
Wind Tunnel Wall Corrections
Presentation of Results
Other Related Tests
Rotor Whirl Tower
Download Test Facilities
PROPULSION
PROPULSION SYSTEM ANALYSIS
Propulsion Techniques
Gas Turbine Engine Characteristics
Cycle Description
Specific Fuel Consumption (SFC)
Specific Power
Process Analysis
Inlet
Compressor
Combustor
Turbine
Exhaust Duct
Other Considerations
Partial Power Cycle Analysis
Reaction Systems
Hot Gas Cycle
Tip Jet
ENGINE CHARACTERISTICS AND SELECTION
Basic Consideratios
Gas Turbine Engine
Coupled and Free Power Turbine Engines
Cycle Modifications
Selection of Design Point Cycle Parameters
Partial Power Operation
Analytical Design
Control System
Simple Control System
Variable-geometry Control System
ROTOR AND PROPELLER ANALYSIS
Rotor Configurations
Rotor Types
Rotor Hub Geometry
Rotor Control Systems
Elements of Rotor Motion
Characteristics of Rotors
Fully Articulated Rotors
Two-bladed Teetering Semirigid Rotors
Modified Two-bladed Rotors
Rigid or Hingeless Rotors
Other Rotor System Considerations
Propeller Selection
Propeller Types
Helicopter Application
Analytical Procedures
Propeller Selection Procedure
Basic Considerations
Definitions
Performance Calculation Method
OTHER PROPULSIVE DEVICES
Propeller Propulsion
Primary Propulsion
Tail Rotor
Shrouded Propeller Propulsion
Turbofan and Turbojet Propulsion
Augmentation Systems
HELICOPTER PRELIMINARY DESIGN STUDY
PARAMETRIC ANALYSIS
Optimization in Helicopter Design
Objective Functions
Constraints
Optimization Techniques
Maximum Seeking Methods
Graphical Techniques
Suboptimization
Basic Relationships for Parametric Analysis
Engine Performance Relationships
Altitude Dependence of Power Output
Temperature Dependence of Available Power
Specific Fuel Consumption
Helicopter Power Requirements
Main Rotor Power
Main-rotor Induced Power
Main-rotor Profile Power
Parasite Power
Power Requirements for Tandem-rotor Configurations
Control Power
Accessory Power
Auxiliary Propulsive Power
Gear and Transmission Power Losses
Total Helicopter Power Requirement
Hover Power Required Out-of-ground Effect (OGE)
Hover Power Required In-ground Effect (IGE)
Power Required in Forward Flight
Power Required to Climb
Fuel Requirements
Fuel Flow in Hover
Fuel Flow in Foiward Flight
Fuel Flow in Climb
Helicopter Weight-estimating Relationships
Techniques of Configuration Selection
Feasible Configurations
Installed Power and Tip Speed Selection
Available Fuel Weight Ratio
Required Fuel Weight Ratio
Fuel Weight Ratio Method
Optimization
Minimum Weight and Minimum Size Configurations
Minimum Cost Configurations
Cost Effectiveness
MISSION PERFORMANCE
Hover Ceiling
General
Method of Analysis
Payload
General
Definition of Weights
Takeoff Gross Weight
Empty Weight
Basic Weight
Fixed Useful Load
Operating Weight
Useful Load
Mission Profile
Mission Profile Definition
Mission Profile Elements
Warmup
Hover At Takeoff
Climb to Cruise Altitude
Cruise at Constant Altitude
Descent to Landing Site
Hover at Landing Site
Reserve Allowance
External Load Mission
Effect of Altitude on Payload-range Capability
Range
Specific Range Parameter Computation
Variation With Gross Weight
Range Index Method
Effect of Altitude and Gross Weight on Range
Effect of Wind on Range Capability
Ferry Range Capability and Range Extension .
Range Parameter in Generalized Form
Breguet Range Equation
Endurance
Analysis Method
Effect of Gross Weight and Altitude on Endurance
Breguet Endurance Equation
Rate of Climb — Maximum and Vertical
Basic Considerations
Forward Climb
Service and Combat Ceilings
Time, Fuel, and Distance to Climb
Vertical Climb
Takeoff and Landing
General
Takeoff Performance
Acceleration
Rotation
Climb
Landing Performance
Approach
Rotation
Deceleration
AIRSPEED-ALTITUDE LIMITS
General
Definitions
Power Constraints
Structural Constraint
Stability Constraints
Maneuverability and Controllability
SPECIAL CONSIDERATIONS
AUTOROT ATIONAL CHARACTERISTICS
Basic Mechanism of Autorotation
Entry into Autorotation
Calculation of the Rate of Descent in Autorotation .
Vertical Autorotation
Forward Flight Autorotation
Glide Distance
Flare
Height-Velocity Curve
Single-engine Helicopters
Multiengine Helicopters
MANEUVERING PERFORMANCE
Power Required in Accelerated Flight
Changing Energy States
Normal Acceleration Capability
Effect of Wings
ENGINE(S) OFF/INOPERATIVE CONDITIONS
Autorotation
Performance With One Engine Inoperative (OEI)
OEI Range and Endurance
Takeoff and Landing
Calculation of Flight Paths
Procedure for Calculating Takeoff and Landing Problems
Weight-altitude-temperature Characteristics
Aircraft Trim Characteristics
LIST OF SYMBOLS
REFERENCES

CHAPTER FOUR
STRUCTURAL DESIGN
INTRODUCTION -
DESIGN FLIGHT SPEEDS -
GROSS WEIGHTS -
FLIGHT AND TAKEOFF LOADING CONDITIONS -
FLIGHT ENVELOPES AND MISSION PROFILES -
Basic Flight Loading Conditions -
Mission Profile and Fatigue Analysis -
LIMIT LOAD FACTORS -
Symmetrical Flight -
Control of Limit Load Factors -
V-n Diagram -
Maneuvers (Symmetrical Flight) -
Rotor Speed and Power Ranges -
Load Factors for Other Than Normal Gross, Weights -
Fatigue Analysis -
Static Analysis -
Asymmetrical Flight -
GUSTS -
Conditions Requiring Gust Load Factors -
Gust Influence -
Gust Loads During Maneuvers -
Fatigue Loadings -
LANDING CONDITIONS -
DESIGN LIMIT LANDING REQUIREMENTS -
Symmetrical Landings -
Design Sinking Velocity -
Landing Attitude Requirements -
Weight and CG Factors -
Evaluation of Vehicle Designs -
Preliminary Substantiation Requirements -
Asymmetrical Landings -
Landing Attitude Requirements -
Weight and CG Factors -
Evaluation of Vehicle Designs -
RESERVE ENERGY REQUIREMENTS -
Reserve Energy Descent Velocities -
Reserve Energy Design Considerations -
Other Considerations -
Autorotational Capability Indices (Landings) -
CRASH LOADS -
Crash Environment -
Structural Design -
Lateral Impact -
Vertical Impact -
Longitudinal Impact -
Combined Vertical and Forward Resultant Velocity -
Rollover -
Landing Gear -
Overhead Masses -
Seat and Restraint System Design -
Other Equipment and Stores -
TAXI AND GROUND-HANDLING LOADING CONDITIONS -
GROUND MANEUVERING -
Braking Conditions -
Two-point Braked Roll -
Three-point Braked Roll -
Unsymmetrical Braking -
Reverse Braking -
. Wheel, Brakes, and Tire Heating -
Turning -
Pivoting -
Taxiing -
Special Tail -gear Conditions -
JACKING AND MOORING CONDITIONS -
Jacking Loads -
Mooring Loads -
TOWING AND TRANSPORT LOADS -
Towing Loads -
Transport Loads -
- MISCELLANEOUS LOADING CONDITIONS -
ROTOR ACCELERATION -
Determination of Ground Idle Rotor Speed -
Determination of Peak Engine Torque -
Rotor Blade Loads -
ROTOR BRAKING LOADS -
- SPECIAL LOADING CONDITIONS -
HARD-POINT LOADS -
External Store Installations -
. Design Criteria -
. Weight -
, Center of Gravity -
. Methods of Analysis -
. Extent of Substantiation -
. Aerodynamic Load Determination -
. Dynamic Loads -
. Flight Load Determination -
Reaction Forces -
Firing Frequency Dynamics -
Blast Overpressures -
EXTERNAL CARGO -
Rigidly Attached External Cargo -
Sling-loaded External Cargo -
. Static Loads -
. . . Aerodynamic Loads -
-S. . . Combined Loads -
-S. . . Asymmetrical Loading -
-S. . Lifting and Aerial Towing -
FLOORING AND WORK PLATFORMS -
Flooring Design Criteria -
Work Platform Design Criteria -
Interchangeability and Replaceability -
Durability -
DOORS AND HATCHES -
Design Criteria -
. Concentrated Loads -
. Distributed Loads -
. Deflection Criteria -
. Production Tolerance -
-S. . Removal and Replacement -
-S. . Emergency Jettison and/or Personnel Egress -
Si/e of Openings -
. Access Openings -
. Entry Openings -
. Egress Openings -
STEPS AND HANDHOLDS -
Steps -
. Size and Clearance Requirements -
. Strength Requirements -
. Other Considerations -
Handholds *
. Size and Clearance Requirements for Handholds -
. Strength Requirements -
Other Considerations -
- STRUCTURAL SUBSTANTIATION, ROTOR, DRIVE AND CONTROL
SYSTEMS -
ROTOR LOADS— STEADY AND UNSTEADY
Airloads -
. Impressed Blade Pitch
. Airflow -
. Rotor Position and Motion -
. Airfoil Characteristics -
. Transient Loads -
Analytic Approach to Rotor Load Prediction -
Preliminary Design Considerations -
HUB LOADS -
Characteristics of Rotor Hubs -
Analysis of Rotor Loads -
. Flapwise Loads -
. Inplane Loads -
Design Loads for Fatigue -
. Endurance Load Level -
. Maneuver Loads -
. Ground-air Load Cycle -
Miscellaneous Loading Conditions -
. Starting and Shutdown Loads -
. Wind Loads -
, Stop-banging Loads -
. Folding Loads -
. Mooring and Tiedown Loads -
. Hoisting Loads -
MECHANICAL DRIVE SYSTEM LOADS -
Load Spectra -
Cubic Mean Load -
Steady Loads -
Fatigue Loads -
Load Analysis for Typical Helicopter -
. Main and Tail Rotor Gearboxes -
.S. Free-wheeling Unit -
.S. Main Transmission Bevel Gear Stages -
. Planetary Gear Stages -
.S Spur and Helical Gear Systems -
. Main Housing Loads -
J Drive Shaft and Coupling Loads -
CONTROL SYSTEM SUBSTANTIATION -
Control System Description -
Description of Load Sources and Reactions -
. Trim Actuators -
. Rate Restrictors -
Hydraulic Boost
Power Systems
Stability Augmentation
Vibration Absorbers
System Stops
Determination of Loads
Ground Condition Load Criteria
Miscellaneous Controls
System Failure Effects
Control System Substantiation
Lower Controls
Static Design Load
Analysis
Material Allowables
Margin of Safety
Rotating and Stationary Upper Controls
Alternating Design Loads
Static Strength
Stiffness Requirements
Structural Concepts
AIRFRAME STRUCTURAL SUBSTANTIATION
FUSELAGE STRUCTURE
Fuselage System Description
Load Sources
Flight Maneuver Loads
Gust Loads
Landing Loads
Crash Loads
Other Loadings
Load Paths
Determination of Loads
Weight Distribution
Unit Shear, Moment, and Torsion Distribution
Specific Maneuver and Landing Condition Load Curves
Critical Condition Selection and Superposition of System Loads
Fail-safe Aspects
Fatigue Considerations
Internal Loads
Preliminary Sizing
Substantiation
WING AND EMPENNAGE SUBSTANTIATION
Basic Considerations
Sign Convention
Inertial Loads
Aerodynamic Load Distribution
Gust Loading
Ground-handling Loads
Mooring, Jacking, Hoist, and Sling Loads
Structural Design Requirements
Combined Loading Conditions
Stress Analysis -
LANDING GEAR SUBSTANTIATION -
Load Factor Determination -
Specific Landing Gear Load Determination -
. Wheel Gear Loads -
. Skid Gear Loads -
. Float Gear Loads -
Reserve Energy Loads -
Preliminary Structural Sizing
Substantiation of Landing Gear Design -
SUBSTANTIATION OF MISSION EQUIPMENT INSTALLATIONS ... -
Equipment Loads -
. Equipment Types -
. . Cabin Equipment -
. . Equipment Outside Cabin but Inside Helicopter -
. . Externally Installed Equipment -
. Load Types -
. . Flight Maneuver Loads -
. . Air Loads -
. . Vibratory Loads -
. Determination of Loads -
Loads on Cabin Equipment -
. . Loads For Equipment Installed Internally but Outside of Cabin -
. . Loads on Externally Attached Equipment -
Load Paths -
Other Considerations -
Preliminary Sizing -
Substantiation -
- FATIGUE LIFE DETERMINATION -
GENERAL -
FATIGUE-CRITICAL COMPONENTS -
FATIGUE LOADINGS -
- Determination of Composite Maneuver Spectrum -
Determination of Gross Weight and Rotor Speed Distributions -
FATIGUE PROPERTIES -
FATIGUE LIFE -
SERVICE LIFE CALCULATION -
• SPECTRUM TESTING -
INFINITE FATIGUE LIFE -
- LIST OF SYMBOLS -
REFERENCES -

CHAPTER FOUR
DYNAMICS
- INTRODUCTION -
- AIRFRAME DYNAMICS AND VIBRATION -
GENERAL -
VIBRATION CONTROL ANALYSIS AND DESIGN TECHNIQUES ... -
Vibration Analysis -
Equations of Motion -
Normal Mode Solution -
Methods of Calculating Normal Modes and Natural Frequencies -
. Stodola Method and Matrix Iteration -
. Myklestad Method -
. Finite Element Analysis -
. Other Methods -
VIBRATION REDUCTION -
Airframe Modification -
Vibration Absorbers -
Vibration Isolation -
. Mathematical Methods -
. Recent Developments -
Fail-safe Design -
EXCITATION SOURCES -
Rotor Forces -
Other Sources -
GROUND RESONANCE -
Description of the Phenomenon -
Important Parameters -
Method of Analysis -
DESIGN CRITERIA AND CONSIDERATIONS -
- ROTOR SYSTEM INSTABILITIES -
GENERAL -
SINGLE-BLADE INSTABILITY ANALYSES -
Single-blade Flutter and Torsional Divergence -
Single-blade Flapping instability
Single-blade Coupled Pitch-flap-lag Instability -
COUPLED ROTOR/ AIR FRAME INSTABILITY ANALYSES -
Multiblade Flutter -
Multiblade Flapping Instability -
. Axial Flow ....'. -
. Oblique Flow -
Coupled Rotor-Airframe Lead-lag Instability -
EFFECT OF ROTOR CONFIGURATION ON INSTABILITIES -
Fully Hinged Rotor -
Semihinged Rotor -
Seesaw Rotor -
Floating Hub Rotor -
Hingeless Rotor -
SUBSTANTIATION CRITERIA AND METHODS -
- LIFTING SURFACE DYNAMICS -
GENERAL -
Definitions -
Basis of Criteria -
FLUTTER -
DIVERGENCE
CONTROL SURFACE BALANCE AND STIFFNESS CRITERIA
Mass Balance of Control Surface
Balance Weights
. Location of Balance Weights
. Rigidity and Strength of Balance Weight Attachments
PROPELLER-NACELLE WHIRL FLUTTER
- DRIVE SYSTEM DYNAMICS
SCOPE
DESIGN PHILOSOPHY AND DESIGN CRITERIA
MATHEMATICAL METHODS
The Mathematical Model
-S. . Solution by Matrix Methods
-S. . Porter’s Method
. Mode Shapes Calculated by Porter’s Method
. Parametric Studies
-S. . . Sample Calculations
S Effect of Rotor Characteristics
Compatibility Between the Drive System and the Engine and Engine Control
System
- LIST OF SYMBOLS
REFERENCES

CHAPTER FIVE
STABILITY AND CONTROL
INTRODUCTION
FUNDAMENTALS OF HELICOPTER STABILITY AND CONTROL
DEFINITIONS
Axis Systems
Gravity Axes
Stability Axes
Body Axes
Choice of Axes
EQUATIONS OF MOTION
STABILITY DERIVATIVES
BASIC STABILITY AND STABILIZATION SYSTEMS
Pertinent Rotor Derivatives
Dynamic Stability of Basic Helicopter
Fundamentals of Automatic Stabilization
Control Input Required
Response Char-cteristics of Mechanical Gyratory Systems
Gust Alleviation
Rotor Sensitivity
Mechanical Feedback Systems
Electronic Feedback Systems

SPECIAL MISSION CONSIDERATIONS -
.I Center of Gravity Travel -
. Single-rotor Helicopters -
. Tandem-rotor Helicopters -
Hover Height Control -
Weapon Platform Requirements -
VFR/IFR Flight -
- FLIGHT DYNAMICS -
CONTROL POWER -
Requirements -
. Control Sensitivity and Damping Requirements -
. Control Sensitivity and Damping Considerations -
. Control Power Requirements -
. Other Control Power Considerations -
Determination of Control Characteristics -
. Pitch and Roll -
. . Single-rotor Helicopters -
. . Tandem-rotor Helicopters -
. Yaw -
. . Single-rotor Helicopters -
. . Tandem-rotor Helicopters -
CONTROL POSITION VERSUS SPEED -
Requirements -
Physical Phenomena Involved -
. Single-rotor Helicopters -
. Tandem-rotor Helicopters -
. Synchropters -
Methods for Calculating Speed Stability -
. Single-rotor Helicopters -
. Tandem-rotor Helicopters -
SPEED STABILITY AND MANEUVERING FLIGHT -
DYNAMIC STABILITY -
EFFECTS OF EXTERNAL STORES -
Angle of Attack -
Attitude -
Aerodynamic Forces and Jettisoning of Stores or Dispensing of Payloads . -
Forced Jettisons -
Effects of External Stores on Static and Dynamic Stability (Laterally Symmet-
rical Loadings) -
Effects of External Stores (Asymmetrical Loadings) -
Effects of Weapon Recoil -
. High-rate-of-fire Weapons -
. Medium- and Low-rate-of-fire Weapons -
- .S. . High-impulse, Single-shot Weapons -
Sling Loads -
CONTROL SYSTEMS -
Control Feel -
. Force Feel -
. Control Forces -
. Control Linkage -
Control Harmony -
Trim Systems -
- STABILITY AUGMENTATION -
STABILITY REQUIREMENTS -
STABILITY AUGMENTATION SYSTEMS (SAS) -
Pitch Control -
Normal Acceleration Control -
Long-period Mode -
Hardware -
Gust Alleviation -
Dynamic Instability ; -
STABILITY AUGMENTATION SYSTEM FAILURE ANALYSIS -
Passive Failures -
Hardover Failures -
Null-oftset Failures -
, SAS Monitoring -
Redundancy -
Other Considerations -
AUTOMATIC STABILIZATION EQUIPMENT -
Pilot-assist Modes -
. Attitude-Hold -
. Heading-Hold/Select Mode -
. Control Stick Maneuvering -
. . Disconnect Maneuvering -
. . Position Proportional Maneuvering -
. . Force Proportional Maneuvering -
. Automatic Turn Coordination -
. Altitude-hold and Altitude-select -
t. Velocity Vector Control -
Guidance Modes -
.I Automatic Navigation -
. Automatic Transition -
. Automatic Hover -
. Automatic Stationkeeping -
. Automatic Terrain-following -
Automatic Stabilization Equipment Failures -
. Passive Failures -
i . Kardi.iOr Failures -
j - LIST OF SYMBOLS -
REFERENCES -

CHAPTER SIX
DRIVE SYSTEM DESIGN
INTRODUCTION -
TRANSMISSION SYSTEMS -
Gears
Clutches -
, Transmission Shafting -
Bearings and Housings -
Lubrication ¦ -
Accessories -
ROTOR BRAKES -
- SYSTEM SELECTION -
GENERAL -
BASIC GEARED TRANSMISSION TYPES -
Spur Gears -
?. Helical Gears -
Bevel Gears -
Planetary Gearing -
Miscellaneous Types of Gearing -
- TRANSMISSION REQUIREMENTS -
GEAR SYSTEMS -
Design Considerations -
. Life-load Relationship -
. Suggestions for Good Design Practice of Gearboxes -
. Gearbox Lubrication Considerations -
. Recess Action Gears -
Preliminary Gearbox Weight Considerations -
BEARINGS -
- .i Typical Installations -
. Accessory Bearings -
. Plate Thrust Bearings -
Special Purpose Bearings -
. Transmission Main Drive Train -
. Oscillating or Limited Motion Bearings -
Mountings -
Seals -
. . . Integral Type -
. Separate Type -
Installation Considerations -
. Lubrication -
. Inner and Outer Ring Shaft and Housing Fits -
Common Problems in Bearing and Support Application -
fatigue Considerations -
LUBRICATION -
Lubrication Systems . ¦<¦
. Splash Lubrication System -
. Circulating Lubrication Systems -
. Lubricating Oil -
Lubrication System Components and Arrangement -
Oil Flow Requirements -
HEAT REJECTION AND TRANSMISSION EFFICIENCY -
Gear and Bearing Losses -
. Preliminary Gear and Bearing Loss Predictions -
. Gear and Bearing Loss Calculations -
Windage and Churning Losses
Conversion of Losses to Heat Loss and Efficiency
TRANSMISSION DESIGN
MAIN ROTOR TRANSMISSION
ANTITORQUE ROTOR TRANSMISSION
COMBINING TRANSMISSION
Functions
Typical Combining Transmissions
ENGINE/ROTOR CROSS-SHAFTING
Functions and Features
Shafting
Couplings
ACCESSORY DRIVES
Helicopter Accessories
Accessory Drive Arrangement
Accessory Drive Pads
Specifications
State-of-the-Art
FAILURE WARNING SYSTEMS
SHAFTS
SHAFT DESIGN
Design Parameters
Strength/Weight
Dynamic Considerations
Shaft End Configurations
Vulnerability
Large- vs Small-diameter Shafts
SHAFT DYNAMICS
Critical Speeds
Mathematical Methods
Nonuniform Shafts
Uniform Shafts
Effects of Elasticity and Restraints at Bearings . .
Effects of Masses Concentrated Between Bearings
Gyroscopic Effects
Other Effects
Design Criteria
CLUTCHES, BRAKES, AND COUPLINGS
CLUTCHES
Sprag Theory
Sprag Clutch Design
Torque Capacity
Inner Race Hertz Stress
Overrunning Clutch Races
Positive Continuous Engagement Sprag
Overrunning Capability and Lubrication
Roller Clutch
SPLINES
Types of Splines
Paragraph Page
Typical Applications -
Design Considerations -
Spline Capacity (SAE Type) -
Materials, Metallurgy, and Lubrication -
Failure Modes -
MECHANICAL COUPLINGS -
Laminated Ring Couplings -
Flexible Disk Couplings -
Gear Couplings -
Universal Joints -
Elastomeric Couplings -
Shaft Installation -
ROTOR BRAKES -
Need for Rotor Brakes -
Full On/OfT vs Controllable Systems -
Description of a Typical Simple System -
' Predesign Sizing Considerations -
Service Experiences -
- ISOLATION SYSTEMS -
- LIST OF SYMBOLS -
REFERENCES -

CHAPTER SEVEN
POWER PLANT SELECTION AND INSTALLATION
- INTRODUCTION -
SELECTION -
ENGINE POWER OUTPUT SHAFT -
ENGINE REPLACEMENT . -
ENGINE AIR INDUCTION SYSTEM -
ENGINE STARTING SYSTEM -
LUBRICATION, COOLING, AND EXHAUST SYSTEMS -
FUEL SYSTEM -
SECONDARY POWER SYSTEM -
POWER MANAGEMENT SYSTEM -
AUXILIARY POWER UNIT (APU) -
SAFETY REQUIREMENTS -
- ENGINE INSTALLATION CONSIDERATIONS -
ENGINE MOUNTING AND VIBRATION ISOLATION -
Engine Mounting Considerations -
Engine Mounting Forces and Reactions -
Engine Vibration Isolation -
Engine Mount Installation Considerations -
ENGINE AIR INDUCTION SYSTEM -
General Design -
Air Induction System Inlet Location -
S Engine Air Induction System Pressure Losses -
Evaluation of Pressure Losses -
TABLE OF CONTENTS (Continued)
.S Foreign Object Damage (FOD) -
Engine Air Particle Separator (EAPS) -
. Inertial Separators -
S . Vortex Tube Inettial Separators -
. Centriftipl (Inertial) Separator -
. EAPS Scavenge Pump -
Power Losses -
Air Induction System Anti-icing Provisions -
EXHAUST SUBSYSTEM -
Exhaust Wake -
Engine Exhaust Noise -
Performance Losses -
S Infrared Radiation Suppression -
.S Estimation of Exhaust I R Emissions -
PROPULSION SYSTEM COOLING
Insulation -
Heat Exchangers -
S Fans -
Engine Compartment Cooling -
Cooling System Air Inlet -
Ejectors -
Survivability Upon Loss of Cooling System -
Cooling Power Requirements -
ACCESSORIES -
Bleed-air-driven Accessories -
Mechanically Driven Accessories -
Mechanical Power Extraction -
S Future Drive Designs -
.S Effect of Air and Power Extraction -
Redundancy Requirements -
MAINTENANCE -
- SUMMATION OF POWER LOSSES -
GENERAL -
ENGINE INSTALLATION LOSSES -
Air Induction System Pressure Loss -
Exhaust Pressure Rise -
Engine Inlet Temperature -
Power Extraction -
Engine Air Eleed -
Air Induction Anti-ice -
Charts for Presentation of Installed Power -
LOSSES BETWEEN ENGINE SHAFT AND MAIN ROTOR -
Transmission Efficiency -
S Power Required for Antitorque -
Accessories -
- FUEL AND LUBRICATION SYSTEMS -
FUEL SYSTEM REQUIREMENTS -
REQUIREMENTS FOR OIL SYSTEMS -
Oil Tanks -
Oil Lines and Couplings -
S Olhcr Oil System Components -
S Oil Cooler -
- PROPULSION SYSTEM FIRE PROTECTION -
GENERAL -
FIRE PREVENTION -
FIRE CONTAINMENT -
FIRE DETECTION SYSTEMS -
FIRE EXTINGUISHING SYSTEMS -
- ENGINE-STARTING SYSTEMS -
GENERAL -
STARTING SYSTEM SELECTION -
Engine Parameters -
Starter Parameters -
Self-contained Power Sources -
CARTRIDGE-BOOSTED ELECTRICAL STARTING SYSTEMS -
AUXILIARY POWER UNIT (APU) INSTALLATIONS -
Major APU Types -
l.l Shaft Power -
. Compressed Air Power -
t . Compressed Air Bleed Combined With Combustion Products *
) S Trade-off Considerations for APU Selection -
S . Self-sufficiency -
S . Ground Support Functions -
S . Flight or Alternate Support Functions -
S . Weight Optimization -
. . Electrical Energy Transfer -
?.. . Hydraulic Energy Transfer -
S . . Pneumatic Energy Transfer -
S . . Direct Drive Energy Transfer -
S . . Combination Energy Transfer -
. Space Opti.nLuiion -
. APU Performance -
APU/Helicopter Interface Considerations -
- ENGINE/AIRFRAME INTEGRATED CONTROL SYSTEM -
GENERAL -
ROTOR SPEED REQUIREMENTS -
POWER MANAGEMENT REQUIREMENTS -
ENGINE LIMIT CONTROL REQUIREMENTS -
INTEGRATED CONTROL REQUIREMENTS -
- , . Proportional Control System -
Rotor System Response -
Engine and Rotor Damping -
ENGINE RESPONSE -
COLLECTIVE PITCH SIGNAL
Variable Gain Devices - !
Slow Time Constant Governors -
Isochronous Controls -
Load-sharing -
NONUNEAR ANALYSIS -
EMERGENCY AND AUTHORITY LIMITATIONS -
ENGINE STARTING AND POWER CONTROL LEVER SYSTEMS . . . -
LIST OF SYMBOLS -
REFERENCES -

CHAPTER EIGHT
SECONDARY POWER SYSTEMS
- INTRODUCTION -
- SUBSYSTEM SELECTION -
GENERAL -
Maintainability and Reliability Considerations -
Safety -
PERFORMANCE CALCULATIONS - ’>
Takeoff Weight Penalty Method -
. Fixed Weight Penalty -
. Variable Weight Penalty -
. Ram Air Drag Penalty -
. Bleed Air Penalty -
. Shaft Horsepower Extraction Penalty -
Breguet Range Equation -
- ELECTRICAL SYSTEMS -
GENERAL -
Electrical Load Analysis -
DC Systems -
AC Systems -
. Constant-speed Drive System -
. Air Turbine System -
. Controlled-speed Hydraulic Motor System -
. Cycloconverter System -
. High-voltage DC System -
DC ELECTRICAL SYSTEMS -
System Description -
Weight Analysis -
VARIABLE-FREQUENCY AC ELECTRICAL SYSTEM -
System Description -
| Weight Analysis -
CONSTANT-FREQUENCY AC SYSTEM -
WEIGHT COMPARISON -
CF AC SYSTEM WITH ONBOARD APU -
System Description -
Weight Analysis -
PROTECTION -
Direct Current System Protection -
Isolated AC System Protection -
Parallel AC System Protection -
PARALLEL VERSUS NONPARALLEL OPERATION -
Parallel Operation -
Ncnparallel Operation -
ELECTRICAL SYSTEM RELIABILITY -
ELECTRICAL SYSTEM SAFETY -
EMERGENCY SYSTEMS -
DISTRIBUTION SYSTEM -
ELECTROMAGNETIC COMPATIBILITY (EMC) -
- HYDRAULIC SYSTEMS -
GENERAL -
TRADE-OFF CONSIDERATIONS -
Mission Performance Requirements -
System Trade-offs -
. System Pressure Trade-offs -
. Trade-offs Among Constant-pressure, Variable-flow; Constant-flow; and
Load-sensitive Systems -
. Central Hydraulic Systems Versus Remotely Located Packaged Hydraulic
Systems -
System Filtration Trade-offs -
Fluid Selection .
Survivability/reliability Trade-offs -
System Reservoir Trade-off -
I V..../ . . Line Size Optimization -
System Packaging Trade-offs -
System Line and Fitting Tradeoff -
SURVEY OF MILITARY SPECIFICATION REQUIREMENTS -
System Type -
System Class -
System Operation -
| System/Component Design -
| DESIGN FEATURES -
I Reservoirs -
I . . Accumulators -
I . . System Pressure Relief Valves -
f . . Filters -
I . . Statie and Dynamic Seals -
I . . Distribution System -
} . . . Fittings -
| . . . Tubing -
. . . Hose Assemblies -
. . Functional Subsystems -
. . . Flight Control Subsystems -
. . . Utility Systems -
. . Engine-starting Systems -
. SAFETY. OPERATIONAL RELIABILITY, AND SURVIVABILITY CON-
SIDERATIONS -
. . Routing the System -
. . Component and Subsystem Design -
. . Instrumentation -
. Protection of Pressure Sensors and Transmitters -
- , . . Pressure-sensing Elements -
Survivability Considerations -
HYDRAULIC SYSTEM POWER ANALYSIS -
Flight Control Hydraulic System Analysis -
Utility Hydraulic System Analysis -
- PNEUMATIC SYSTEMS -
COMPARATIVE CHARACTERISTICS BETWEEN PNEUMATIC AND
HYDRAULIC SYSTEMS -
TYPES OF PNEUMATIC SYSTEMS -
Airborne Compressor-charged System -
Ground-charged Storage Bottle System -
-S. . Hot-gas, Solid-propellant Gas Generator Systems -
SYSTEM INSTALLATION -
SAFETY, MAINTENANCE, AND RELIABILITY -
SYSTEM ANALYSIS -
- FLUIDIC SYSTEMS -
GENERAL -
FLUIDICS COMPARED TO ELECTRONICS -
FLUIDIC COMPONENT DEVELOPMENT STATUS -
DESIGN AND TEST SPECIFICATIONS -
EXAMPLE OF A HELICOPTER FLUIDIC SYSTEM -
System Design Requirements -
System Mechanization -
Component Description -
- .S. Comparison With Equivalent Electronic System -
Flight Test -
AUXILIARY EQUIPMENT -
Power Supplies -
. Pneumatic Power -
. Hydraulic Power -
Transducers -
- ENVIRONMENTAL CONTROL SYSTEMS -
GENERAL -
DESIGN REQUIREMENTS -
CONCEPTUAL DEVELOPMENT AND SYNTHESIS -
Distribution Systems -
- , . Heating and Ventilating Systems -
- , . Air-cycle Systems -
Vapor-cycle Refrigeration Systems -
Thermionic Cooling Systems (Avionics) -
TRADE-OFF STUDIES AND SELECTION -
- LIST OF SYMBOLS -
REFERENCES -

CHAPTER NINE
WEIGHT AND BALANCE
INTRODUCTION -
WEIGHT ENGINEERING -
IMPORTANCE OF WEIGHT AND BALANCE CONTROL -
GROWTH FACTOR -
WEIGHT ENGINEERING GROUP -
WEIGHT CONTROL -
Weight Control Program -
Preliminary Weight Prediction -
Weight Estimation and Calculation -
Mass Property Analysis -
Moments of Inertia -
Center of Gravity Envelope -
Weight Control Status Reporting -
Actual Weight and Balance Determination -
DOCUMENTATION -
Summary Weight Statement -
Weight and Balance Status Form -
DEFINITIONS OF WEIGHT TERMS -
REFERENCES -

CHAPTER TEN
MAINTAINABILITY
INTRODUCTION -
IMPLEMENTATION -
MAINTENANCE ALLOCATION AND THE MAINTENANCE ENVI-
RONMENT -
MAINTENANCE-INDUCED FAULTS -
INTERCHANGEABILITY AND REPLACEABILITY -
INTERCHANGEABILITY -
REPLACEABILITY -
STANDARDIZATION -
ACCESSIBILITY -
SPECIAL TOOL CONSIDERATIONS -
MAXIMUM TIME BETWEEN OVERHAULS (TBO) -
FACTORS IN DETERMINING OPTIMUM TBO , -
ADVANCES IN AIRBORNE MONITORING SYSTEMS -
MINIMUM INSPECTION -
GROUND SUPPORT EQUIPMENT (GSE) INTERFACE -
REFERENCES '-

CHAPTER ELEVEN
I RELIABILITY AND AVAILABILITY
INTRODUCTION
AVAILABILITY. COMPLEXITY. AND RELIABILITY
IMPROVING RELIABILITY
RELIABILITY PREDICTION
Purpose and Scope
System and Component Reliability
MISSION REQUIREMENTS AND COMPLETION
RELIABILITY REQUIREMENTS
MISSION COMPLETION
SYSTEM AND COMPONENT RELIABILITY
STATISTICAL SIGNIFICANCE
ESTIMATING WITHOUT DATA
RELIABILITY MODELING
MTBF Assumptions
MTBF Assumption No. — Constant Hazard
MTBF Assumption No. — Random Failures
MTBF Assumption No. — Homogeneous Equipment
MTBF Assumption No. — Perfect Restoration
MTBF Assumption No. — Independence
Exponential Distribution
RELIABILITY PREDICTION, APPORTIONMENT, AND ASSESSMENT
GENERAL
Prediction
Apportionment
Assessment
PROGRAM LIFE CYCLE
Development Phase
Qualification Phase
Manufacturing Phase
SCOPE OF APPLICATION
EXECUTION OF ACTIVITY
Antecedent Requirements
Helicopter System Definition
Profiles
Data Base
Prediction
Techniques
Activity Sequence
Apportionment
Techniques
Activity Sequence
Assessment
Techniques
Activity Sequence
RELIABILITY SUBSTANTIATION
GENERAL
RELIABILITY PROGRAM PLAN
Reliability Substantiation During Design
Apportionment/PreQiction
Assessment of Design Criteria
Design Reviews
. Design Support Tests
Reliability Substantiation During Test
. Assessment
. Substantiation Testing
- , . . Substantiation Testing Process
. Reliability Model
- AVAILABILITY
GENERAL
DESIGN INFLUENCE ON AVAILABILITY
Serviceability
Modularization
Standard Versus Nonstandard Parts
FACTORS IN HELICOPTER DOWNTIME
Logistics
- , . Maintainability
Policy Factors
- SYSTEM SAFETY
- LIST OF SYMBOLS
REFERENCES
CHAPTER TWELVE
CONFIGURATION AND ARRANGEMENT
INTRODUCTION
CONFIGURATION RESTRAINTS
Rotor Clearance
Engine Installation
Interior Arrangement
Transportability
Personnel Emergency Egress
Fuel Storage
Aerodynamic Requirements
Turnover Angle
Step Height
Weapon Clearance
Rear Ramp
Other Restraints
PRELIMINARY DESIGN CONSIDERATIONS
TRANSPORTABILITY REQUIREMENTS
GENERAL
Sectionalization
Preparation for Shipment
Tiedown and Lifting Points
Assistance
AIR TRANSPORTABILITY
Aircraft Size and Weight Limitations
Terminal Facilities
. HIGHWAY TRANSPORT
. . Cargo Vehicles
. . Size and Weight Limitations
. . Van Loading
. . Restraint
. WATERBORNE TRANSPORT
. RAIL TRANSPORT
MAN/MACHINE CONSIDERATIONS
. HUMAN FACTORS ENGINEERING
Anthropometries
. Body Dimensions
. Muscular Strength
Vision
. Glare
. Light Transmission, Reflection, and Fogging
. Adverse Visual Effects
. Optimal Visual Areas
. Cathode Ray Tube (CRT) and Other Light-emitting Displays
System Analysis
. Flowcharting
. Function Analysis
. Operational Sequence Diagramming
. Definitions of Operator/Maintainer Information Requirements
, . . Operator/Maintainer Task Descriptions and Analyses
General Control Principles
Vibration
. SAFETY AND EFFECTIVENESS OF PERSONNEL
. . Emergency Egress
. . Requirements
. . . Emergency Environments
. . . Human Factors Engineering Considerations
. . . Emergency Egress Preliminary Design
. . Acoustical Noise Level and Suppression
. . . Acoustical Concepts
. . . Hearing Loss
. . . Noise Exposure
. . . DOD Noise Limits
. . . Control of Noise at Source
. . Environmental Considerations
. . . Thermal Stress
. . . Environmental Control System
. . . . Heating Requirements
. . . . Cooling Requirements
. . . . Ventilation Requirements
. . . . Thermal Analysis
. . . ' Atmospheric Contaminants
. . . Oxygen Requirements
LIST OF SYMBOLS
REFERENCES

CHAPTER THIRTEEN
- INTRODUCTION -
COMPETITIONS -
SOLICITATIONS -
- DATA REQUIREMENTS -
- REPORTS, PLANS, AND MISCELLANEOUS DATA -
PRIME ITEM DEVELOPMENT SPECIFICATION -
AIRWORTHINESS QUALIFICATION SPECIFICATION -
WEIGHT AND BALANCE REPORT -
PERFORMANCE DATA REPORT -
STABILITY AND CONTROL REPORT -
STRUCTURAL DESCRIPTION AND DESIGN DATA REPORT
POWER PLANT ANALYSIS REPORT -
POWER PLANT INSTALLATION AND FUEL AND LUBRICATION
SYSTEM REPORT -
FLIGHT CONTROL SYSTEM REPORT -
LANDING GEAR SYSTEM REPORT -
HYDRAULIC AND PNEUMATIC SYSTEM REPORT -
ELECTRICAL SYSTEM REPORT -
ELECTROMECHANICAL ACTUATION SYSTEM REPORT -
ELECTRONIC SYSTEM REPORT -
FLUIDIC SYSTEM REPORT -
ENVIRONMENTAL CONTROL SYSTEM (ECS) AND CREW SERVICE REPORT -
ARMAMENT SYSTEM REPORT -
HYDRODYNAMIC REPORT -
ESCAPE SYSTEM ANALYSIS REPORT -
HUMAN FACTORS ENGINEERING REPORT AND PLAN -
SURVIVABILITY/VULNERABILITY (S/V) REPORT AND PLAN .... -
ELECTROMAGNETIC COMPATIBILITY (EMC! CONTROL PLAN . . -
SYSTEM SAFETY PROGRAM PLAN -
RELIABILITY PROGRAM PLAN -
MAINTAINABILITY PROGRAM PLAN -
PRODUCIBILITY PLAN -
DRAWINGS. SKETCHES, AND SCHEMATIC DIAGRAMS -
GENERAL ARRANGEMENT DRAWING AND SKETCH -
INBOARD PROFILE DRAWING -
STRUCTURAL ARRANGEMENT DRAWINGS -
POWER PLANT INSTALLATION DRAWING -
FLIGHT CONTROL SYSTEM DRAWINGS -
LANDING. BEACHING. AND AUXILIARY GEAR DRAWINGS .... -
HYDRAULIC AND PNEUMATIC SYSTEM SCHEMATIC DIAGRAMS -
ENVIRONMENTAL CONTROL SYSTEM SCHEMATIC DIAGRAMS
CREW SERVICE DRAWING -
ELECTRONIC EQUIPMENT DRAWING -
INSTRUMENT PANEL ARRANGEMENT DRAWING -
INSTRUMENT SYSTEM INSTALLATION DRAWINGS -
EXTERIOR LIGHTING SYSTEM DRAWING -
ANTI-ICING SYSTEM SKETCH -
ARMAMENT INSTALLATION DRAWINGS -
CARGO-HANDLING ARRANGEMENT DRAWING -
TOWING. JACKING, MOORING, AND TIEDOWN SKETCH -
ESCAPE SYSTEM DRAWING -

REFERENCE -
GLOSSARY G-l

LIST OF ABBREVIATIONS AMCP - L-l

SPECIFICATIONS, STANDARDS, AND OTHER GOVERNMENTAL

DOCUMENTS M-l

BIBLIOGRAPHY B-l

INDEX M