Cover
Table of Contents
Acknowledgements
Preface
A Note on Units
CHAPTER 1 Introduction
Brief History of Landing Gear
Design Process
Nomenclature
Book Outline
References
CHAPTER 2 Airfield Compatibility
Flotation/Ground Compatibility
Common Concepts in Ground Compatibility
General Overview
California Bearing Ratio
Modulus of Subgrade Reaction, k
Ground Compatibility Nomenclature
Ground Contact Pressure
Landing Gear Arrangement Nomenclature
Ground Compatibility (Flotation) Analysis
Unpaved Surfaces
Soil and Grass.
Unpaved Analysis Method ASD-TR-68-34.
Alternative Unpaved Analysis Methods.
Gravel/Aggregate Airfields.
Paved Surfaces
Pavement Design Analysis.
Layered Elastic and Finite Element Analysis.
Flexible Pavements-Historic Approach.
Rigid Pavements-Historic Approach.
Pavement Strength Reporting Methods.
Load Classification Number/Load Classification Group Method.
Modern Methods for Paved Runways-ACN/PCN and ACR/PCR.
ACN/PCN.
ACR/PCR.
Membrane and Mat Surfaces
PCASE Software for Flotation Analysis
Engineered Materials Arresting Systems (EMAS)
Snow and Ice Runways
Prepared Snow Runways.
Ice Runways.
Helidecks and Heliports
Naval Vessels/Aircraft Carriers
Aircraft Carriers.
Amphibious Warfare Ships.
Maneuvering
ICAO Airport Standards
Required Maneuvers-NAS3601
Required Maneuvers-Land-Based Military Aircraft
Required Maneuvers-Shipboard Military Aircraft
Surface Texture and Profile
Paved Runways
Micro/Macrotexture
Runway Roughness/Profile and Obstacles
Roughness Measurement Techniques
Power Spectral Density Approach
Boeing Bump Method
International Roughness Index
Short Wavelength Roughness
ProFAA Roughness Evaluation Tool
Industry Standard Roughness Profiles.

Bomb Damage Repair
Arrestor Cables
Unsurfaced Runways
Deck/Helideck
References
CHAPTER 3 Tires
Tire Construction and Terminology
Construction Terminology
Tire Dimensions and Properties
Inflation Pressure
Tire Temperatures
Tire Classification
Selection between Bias and Radial Tires
Manufacturing, Certification, and Standardization
Tire Sizing
Tire Sizing Formulae
Tire Sizing Requirements
Tire Tables
Tire Performance and Modeling
Mechanics of Pneumatic Tires
Rolling Behavior
Turning Behavior
Vertical Stiffness
Braking Behavior
Tire-Ground Friction
Wet Runways and Hydroplaning
Snow and Ice
Wear
Tire Property and Behavior Models
NASA Technical Report R-64
Brush Model and Fiala Model
Beam and String Models
Magic Formula Model
Undesirable Tire Behavior
Spray
Debris Lofting
Tire Failure Modes
Modeling Tire Failure Events
Model 1: Tire Debris Threat Model
Model 3E: Flailing Tire Strip Threat Model
Model 3R: Flailing Tire Strip Threat Model
Model 4: Tire Burst Pressure Effect Threat Model
Understanding the Impact of Tire Failures
References
CHAPTER 4 Wheels, Brakes, and Brake Control
Brakes
Aircraft Deceleration
Brake Sizing
Energy
Kinetic Energy Calculation
Rational Brake Energy Calculation
Torque
Brake Design
Brake Actuation
Mechanical Connection to the Landing Gear Structure
Weight
Wheel and Brake Certification and Recommended Practices
Brake Issues and Concerns
Vibration
Failure and Degradation Modes
Braking Accessories
Brake Cooling Fans
Brake Temperature Measuring Systems
Retraction Braking
Wheels
Bearing Selection and Preload
Over Temperature and Over Pressure Relief
Wheel Mass
Failure Modes
Bearing Failure
Wheel Rim Release
Brake Control.

Brake Control Architectures
Antiskid and Related Functions
Braking Efficiency
Antiskid Dynamics
Antiskid Hardware
Autobrake
Failure Modes
References
CHAPTER 5 Layout, Stability, and Maneuverability
Tricycle Arrangement
Conventional (Taildragger) Configuration
Bicycle Configuration
Maneuvering
References
CHAPTER 6 General Arrangement
Energy Absorption
Aircraft Structural Arrangement
Landing Gear Topologies
Common Considerations
Caster
Wheel Alignment
Cantilever
Cantilever Gear Bearing Overlap
Pogo-Stick Design
Torque Links and Splines
Semi-Articulated
Articulated
Side-Hinged Articulated
Multi-Wheel Bogie Arrangements
Other Configurations
Wheel-Less Configurations
Skids and Skis
Adaptive Structure
Seaplanes, Floats, and Hydrofoils
Air Cushion
References
CHAPTER 7 Shock Absorbers
Damping
Friction Damping
Hydraulic Damping
Other Damping Types
Recoil Damping
Structural Spring Types
Coil Spring
Ring-Spring
Leaf Spring
Elastomeric
Pneumatic
Liquid Spring
Liquid Spring Sizing
Liquid Spring Examples and Issues
Oleo-Pneumatic
Oleo-Pneumatic Sizing
Refinements
Real Gas Model
Inflation Gas Solubility in Oil
Design for Real-World Operation
Example Single Stage Oleo-Pneumatic Shock Absorbers
Multiple Stage Oleo-Pneumatic Shock Absorbers
Active Shock Absorbers
Shock Absorber Design Considerations
Seals
Inflation and Fill Valves
Servicing
Shock Absorber Oil
Single Use Shock Absorbers: Crashworthiness and Space Applications
Rotorcraft Ground Resonance
References
CHAPTER 8 Retraction, Kinematics, and Mechanisms
Retraction/Extension
Sliding Systems
Hinged Systems
Parallelogram Arrangements
Secondary Motion
Additional Hinge Axis
Wheel Rotation.

Planing Mechanisms
Shortening
Bogie Positioning
Bogie-Controlled Articulation
Stabilization, Locking, and Unlocking
Planar Braces
Telescopic Braces
Rolling-Folding Braces
Dual Brace (Rolling-Folding)
Plunger Locks
Over-Center Locks
Self-Breaking Locks
Latch Locks
Ground Locks
Springs
Door Mechanisms
Gear-Actuated Doors
Independently Actuated Doors
Ground Door Opening
Actuation Layout and Loads
Actuator Load Requirements
References
CHAPTER 9 Actuation
Manual Actuation
Hydraulic Actuation
Rotary Hydraulic
Linear Hydraulic
Retraction Actuators
Unlock Actuators
Bogie Pitch Trimmers
Internally Locking Actuators
Collect Lock Actuators.
Segment Lock Actuators.
Electric Actuation
Electro-Hydraulic
Electro-Mechanical
References
CHAPTER 10 Systems
Power Sources - Electrical, Hydraulic, and Pneumatic
Electrical
Hydraulic
Typical Central Hydraulic Systems
Dedicated Systems - Hydraulic Power Packs
Hydraulic Components
Pneumatic
Sensors and Monitoring Systems
Proximity Sensing
Rotary and Linear Position Sensing
Pressure and Temperature Sensing
Electrical and Hydraulic Dressings
Electrical Dressings
Hydraulic Dressings
Weight on Wheels (Air/Ground) Detection
Extension and Retraction
Example Systems
Alternate Extension
Steering and Steering Control
Required Steering Torque
Single Wheel Scrubbing Torque, T s
Dual Wheel Scrubbing Torque, T s
Steering Arrangements
Centering
Steer Motors and Control
Rack and Pinion
Push-Pull
Rotary Steer Motor
Shimmy Damping
Nose Wheel Steering Examples
Tailwheel Steering
Main Gear Steering Examples
Towing Concerns
Landing and Taxi Lights
References
CHAPTER 11 Special Functions
Catapult and Holdback
Jump Strut.

Hiking and Kneeling
Autonomous Taxi
Tire Pre-rotation
Tail Bumper
Weight and Balance
Skis
References
CHAPTER 12 Detail Design
Overview
Structural Materials
Steel and Corrosion Resistant Steel
Aluminum
Titanium
Composites
Surface Treatments
Surface Modification
Wear and Sealing Surface Coatings
Corrosion Protection Coatings
Inspection
Corrosion Avoidance
Stress Corrosion Cracking
Galvanic Corrosion Avoidance
Fasteners
Locking and Dual Locking
Clearance Requirements for Fastener Installation and Maintenance
Pins, Lugs, Sockets, and Bushings
Initial Sizing
Bushings
Grease Grooves
Bushing Installation
Repair Allowance
Grease Fittings and Greasing Provisions
Grease Selection
Pin and Lug Joint Examples
Limits and Fits
Metric System
US Customary (Inch) System
Typical Fit Classes for Landing Gear Components
Springs
Seals
Electrical Bonding, Lightning, and Static Dissipation
Shock Absorber Bearings
Bogie Pivot Joint
Towing, Jacking, and Tie-Down Provisions
Tow Fittings
Jacking
Tie-Down
Emergency Towing (Debogging)
Crashworthiness
Fuse Pins
Maintainability and Murphy Proofing
References
CHAPTER 13 Loads, Structural Analysis, and Testing
Loads
Ground Loads
Asymmetrical Loads on Multiple Wheel Landing Gears
Book Cases
Taxi, Takeoff, and Landing Roll.
Braked Roll Conditions.
Turning.
Tailwheel-Specific Cases.
Nose-Wheel-Specific Cases.
Pivoting.
Reverse Braking.
Rational Loads
Landing Loads
Level Landing Conditions.
Tail-Down Landing Condition.
One Gear Conditions.
Lateral Drift Landing Case (Side Load).
Rebound and Free Extension.
Shock Absorber Pressures.
Sailplane Specific Loads
Level Landing Conditions.
Tail-Down Landing Conditions.

One-Wheel Landing Condition.