Stability and Control of Airplanes and Helicopters

Stability and Control of Airplanes and Helicopters deals with aircraft flying qualities that determine the stability and control of airplanes and helicopters. It includes problems based on real aircraft, selected to represent the gamut from simple to complicated, and from conventional utility designs to futuristic research types. Many of these problems involve comparison of theory and experiment to demonstrate their mutual relationship.

Comprised of 25 chapters, this book begins with a discussion on the aerodynamics of the component parts related to the lift and moment characteristics of an airplane, including wings and associated accessories; bodies such as fuselages, nacelles, and tip tanks; and control surfaces. The reader is then introduced to some mathematical techniques for linear differential equations; steady flight at different speeds; and stick force and control-free stability. Subsequent chapters focus on flaps and high-lift devices; power and compressibility effects; and the manner in which the aircraft responds to the application of control. Aeroelasticity and longitudinal equations of motion are also examined.

This monograph is intended for undergraduate and graduate students taking modern engineering courses.

Preface

I. Some Aerodynamic Generalities

1. Wings of Medium to High Aspect Ratio

2. Camber and Twist; Flaps

3. Slender-Body Theory

4. Slender-Wing Theory

Problems

II. Some Mathematical Techniques for Linear Differential Equations

1. Classical Routines

2. Laplace Transforms

3. Root Locus and Related Procedures

4. Analog Computers

Problems

III. Introduction to Longitudinal Stability

1. Introduction

2. Newton's Law: Inertia Forces and Moments

3. Classification of Stability Problems

4. Longitudinal Equations of Motion

5. Control Position versus Velocity

Problems

IV. Steady Flight at Different Speeds

1. The "Simple" Airplane: Rigid, Low-Speed Glider

2. Control Angle for Trim

3. Estimation of Parameters

4. Example

5. Experimental Methods

Problems

V. Stick Force and Control-Free Stability

1. Hinge-Moment Coefficients and Derivatives

2. Control-Free Static Stability and Force to Trim

3. Aerodynamic Balance

Problems

VI. Constant Speed Flight Conditions with Normal Acceleration; Pull-Ups

1. Load Factor

2. Pitch Damping

3. Maneuver Point and Maneuver Margin

4. Stick-Free Maneuver Point and Stick Force per g

5. Steady Turns

Problems

VII. Flaps and High-Lift Devices

1. Stabilizer Effectiveness, Cmit

2. Downwash, dε|dα

3. Control Angle for CLmax; Free Flight

4. Force Trim Change

5. CLmax in Ground Effect

6. Other High-Lift Devices

Problems

VIII. Power Effects

1. Effect of Power on Lift

2. Angle-of-Attack Stability and Maneuver Points

3. Neutral Point and Velocity Stability

4. Trim Changes Due to Power

Problems

IX. Compressibility Effects

1. Subsonic Configuration

2. Supersonic Configuration

Problems

X. Aeroelasticity

1. Maneuver Point ; Angle-of-Attack Stability

2. Neutral Point ; Speed Stability

3. Lateral-Directional Aeroelastic Effects

Problems

XI. Longitudinal Linearized Equations and Derivatives

1. Linearized Equations

2. Drag Equation Coefficients

3. Lift Equation Coefficients

4. Moment Equation Coefficients

Problems

XII. Characteristic Longitudinal Transients—Restricted Degrees of Freedom

1. Vertical Freedom

2. Pitching Freedom in Straight-Line Motion

3. Vertical and Pitching Freedom at Constant Speed

4. Freedom Along the Flight Path

5. Vertical and Horizontal Freedom at Constant Angle-of-Attack

Problems

XIII. Longitudinal Transients and Control Response

1. Effects of Derivatives and Parameters

2. Characteristic Equation; Approximate Factorization

3. Angle-of-Attack Response to Control

Problems

XIV. Longitudinal Dynamics—Special Problems

1. Control-Free Dynamic Stability

2. Longitudinal Dynamics Along Steep Trajectories

3. Short Period Stability; Acceleration and Density Effects

4. Perturbation Stability of an Orbiting Satellite

Problems

XV. Lateral-Directional Equations and Derivatives

1. Decoupling and Linearization

2. Dimensionality

3. Axes

4. The Side Force Equation

5. The Rolling Moment Equation

6. The Yawing Moment Equation

Problems

XVI. Lateral-Directional Statics; Control for Trim

1. Steady Turns

2. Steady Sideslips

3. Cross-Winds, Unsymmetric Power, and Two-Control

4. Steady Rolling

5. Lateral Stick Forces

Problems

XVII. Characteristics Lateral-Directional Transients

1. Roll Mode

2. Spiral Mode

3. Approximate Dutch-Roll Mode

4. True Dutch Roll: Effects of Configuration and Derivatives

5. Roll Coupling

6. Control-Free Dynamics

Problems

XVIII. Roll Response to Control

1. Roll Freedom Only ; No Yaw or Sideslip

2. The Human Pilot, Closed-loop Roll Control

3. Roll Response With Yaw but Without Sideslip

4. Complete Roll Response

Problems

XIX. Airplane Configuration

1. Low-Speed (Below Compressibility) Airplanes

2. High Subsonic Mach Number Airplane

3. Low Supersonic Speeds

XX. Rotor Aerodynamics

1. Physical Principles

2. Formulas for Rotor Forces

Problems

XXI. Longitudinal Equations of Motion

1. Drag Equation

2. Lift Equation

3. Moment Equation

Problems

XXII. Longitudinal Trim in Forward Flight

1. Four Problems of Trim Calculation

2. Four Speed-Trim Gradients

3. Four Acceleration-Trim Gradients

4. Stick Force Gradients

Problems

XXIII. Longitudinal Dynamics

1. Hovering

2. Forward Flight

Problems

XXIV. Lateral-Directional Motions

1. Equations and Derivatives

2. Steady-State Flight Conditions

3. Lateral-Directional Dynamics

4. Transient Response to Lateral Control

Problems

XXV. Other Vtol Configurations

1. The See-Saw Rotor

2. Pitch-Flap Coupling

3. "Lagged" Angular Damping

4. Artificial Stability, in General

5. Rigid Rotor

6. Rotor Position—Articulated Rotor

7. The Flying Platform

8. Tandem Rotor Helicopter

9. Compound Helicopter

10. Autogyro

11. Ducted Rotor

12. Tilt-Thrust Vehicles

Notation

Appendix I. Aerodynamic and General Data for Seven Aircraft

1. The Grumman "Mohawk"

2. The North American F-100 Jet Fighter

3. The Boeing 707 Series Jet Transport

4. The Convair B-58 Jet Bomber

5. The Bell X=1 Research Airplane

6. The North American-NASA X-l5 Research Airplane

7. The Sikorsky S-58 Helicopter

Appendix II. Change of Stability Derivatives with Rotation of Axes

Appendix III. The Standard Atmosphere

Selected Bibliography

Subject Index