Airplane Stability and Control, Second Edition

Transcription

1 Airplane Stability and Control, Second Edition A History of the Technologies That Made Aviation Possible MALCOLM J. ABZUG ACA Systems E. EUGENE LARRABEE Professor Emeritus, Massachusetts Institute of Technology CAMBRIDGE UNIVERSITY PRESS

2 Preface page xvii 1 Early Developments in Stability and Control Inherent Stability and the Early Machines The Problem of Control Catching Up to the Wright Brothers The Invention of Flap-Type Control Surfaces and Tabs Handles, Wheels, and Pedals Wright Controls Bleriot and Deperdussin Controls Stability and Control of World War I Pursuit Airplanes Contrasting Design Philosophies Frederick Lanchester G. H. Bryan and the Equations of Motion Metacenter, Center of Pressure, Aerodynamic Center, and Neutral Point 11 2 Teachers and Texts Stability and Control Educators Modern Stability and Control Teaching Methods Stability and Control Research Institutions Stability and Control Textbooks and Conferences 17 3 Flying Qualities Become a Science Warner, Norton, and Allen The First Flying Qualities Specification Hartley Soule and Floyd Thompson at Langley Robert Gilruth's Breakthrough S. B. Gates in Britain The U.S. Military Services Follow NACA's Lead Civil Airworthiness Requirements World-Wide Flying Qualities Specifications Equivalent System Models and Pilot Rating The Counterrevolution Procurement Problems Variable-Stability Airplanes Play a Part Variable-Stability Airplanes as Trainers The Future of Variable-Stability Airplanes The V/STOL Case 39 IX

3 3.16 Two Famous Airplanes Changing Military Missions and Flying Qualities Requirements Long-Lived Stability and Control Myths 44 4 Power Effects on Stability and Control Propeller Effects on Stability and Control Direct-Thrust Moments in Pitch Direct-Thrust Moments in Yaw World War II Twin-Engine Bombers Modern Light Twin Airplanes Propeller Slipstream Effects Direct Propeller Forces in Yaw (or at Angle of Attack) Jet and Rocket Effects on Stability and Control Jet Intake Normal Force Airstream Deviation Due to Inflow Special VTOL Jet Inflow Effects Jet Damping and Inertial Effects 55 5 Managing Control Forces Desirable Control Force Levels Background to Aerodynamically Balanced Control Surfaces Horn Balances Overhang or Leading-Edge Balances Frise Ailerons Aileron Differential Balancing or Geared Tabs Trailing-Edge Angle and Beveled Controls Corded Controls Spoiler Ailerons Spoiler Opening Aerodynamics Spoiler Steady-State Aerodynamics Spoiler Operating Forces Spoiler Aileron Applications Internally Balanced Controls Flying or Servo and Linked Tabs Spring Tabs Springy Tabs and Downsprings All-Movable Controls Mechanical Control System Design Details Hydraulic Control Boost Early Hydraulic Boost Problems Irreversible Powered Controls Artificial Feel Systems Fly-by-Wire Remaining Design Problems in Power Control Systems Safety Issues in Fly-by-Wire Control Systems Managing Redundancy in Fly-by-Wire Control Systems Electric and Fly-by-Light Controls 89

4 XI 6 Stability and Control at the Design Stage Layout Principles Subsonic Airplane Balance Tail Location, Size, and Shape Estimation from Drawings Early Methods Wing and Tail Methods Bodies Wing-Body Interference Downwash and Sidewash Early Design Methods Matured- DATCOM, RAeS, JSASS Data Sheets Computational Fluid Dynamics Estimation from Wind-Tunnel Data 97 7 The Jets at an Awkward Age Needed Devices Are Not Installed F4D, A4D, and A3D Manual Reversions Partial Power Control Nonelectronic Stability Augmentation Grumman XF1 OF Jaguar Successful B-52 Compromises The B-52 Rudder Has Limited Control Authority The B-52 Elevator Also Has Limited Control Authority The B-52 Manually Controlled Ailerons Are Small The Discovery of Inertial Coupling W H. Phillips Finds an Anomaly The Phillips Inertial Coupling Technical Note The First Flight Occurrences The 1956 Wright Field Conference Simplifications and Explications The F4D Skyray Experience Later Developments Inertial Coupling and Future General-Aviation Aircraft Spinning and Recovery Spinning Before Advent of the Free-Spinning Wind Tunnels Systematic Configuration Variations Design for Spin Recovery Changing Spin Recovery Piloting Techniques Automatic Spin Recovery The Role of Rotary Derivatives in Spins Rotary Balances and the Steady Spin 129

5 All Contents 9.8 Rotary Balances and the Unsteady Spin Parameter Estimation Methods for Spins The Case of the Grumman /American AA- IB The Break with the Past Effects of Wing Design on Spin Entry and Recovery Drop and Radio-Controlled Model Testing Remotely Piloted Spin Model Testing Criteria for Departure Resistance Vortex Effects and Self-Induced Wing Rock Bifurcation Theory I Departures in Modern Fighters Tactical Airplane Maneuverability 14" 10.1 How Fast Should Fighter Airplanes Roll? I Air-to-Air Missile-Armed Fighters Control Sensitivity and Overshoots in Rapid Pullups Equivalent System Methods Criteria Based on Equivalent Systems Time Domain-Based Criteria I Rapid Rolls to Steep Turns ' Supermaneuverability, High Angles of Attack Unsteady Aerodynamics in the Supermaneuverability Regime The Transfer Function Model for Unsteady Flow The Inverse Problem I Thrust-Vector Control for Supermaneuvering Forebody Controls for Supermaneuvering Longitudinal Control for Recovery Concluding Remarks I High Mach Number Difficulties A Slow Buildup The First Dive Pullout Problems P-47 Dives at Wright Field P-51 and P-39 Dive Difficulties Transonic Aerodynamic Testing Invention of the Sweptback Wing Sweptback Wings Are Tamed at Low Speeds Wing Leading-Edge Devices Fences and Wing Engine Pylons ' Trim Changes Due to Compressibility Transonic Pitchup Supersonic Directional Instability Principal Axis Inclination Instability High-Altitude Stall Buffet Supersonic Altitude Stability Stability and Control of Hypersonic Airplanes 1 86

6 12 Naval Aircraft Problems Standard Carrier Approaches Aerodynamic and Thrust Considerations Theoretical Studies Direct Lift Control The T-45 A Goshawk The Lockheed S-3 A Viking Concluding Remarks Ultralight and Human-Powered Airplanes Apparent Mass Effects Commercial and Kit-Built Ultralight Airplanes The Gossamer and MIT Human-Powered Aircraft Ultralight Airplane Pitch Stability Turning Human-Powered Ultralight Airplanes Concluding Remarks Fuel Slosh, Deep Stall, and More Fuel Shift and Dynamic Fuel Slosh Deep Stall Ground Effect Directional Stability and Control in Ground Rolls Vee- or Butterfly Tails Control Surface Buzz Rudder Lock and Dorsal Fins Flight Vehicle System Identification from Flight Test Early Attempts at Identification Knob Twisting Modern Identification Methods Extensions to Nonlinearities and Unsteady Flow Regimes Lifting Body Stability and Control Safe Personal Airplanes The Guggenheim Safe Airplane Competition Progress after the Guggenheim Competition Early Safe Personal Airplane Designs and 1966 NACA and NASA Test Series Control Friction and Apparent Spiral Instability WingLevelers The Role of Displays Inappropriate Stability Augmentation Unusual Aerodynamic Arrangements Blind-Flying Demands on Stability and Control Needle, Ball, and Airspeed Artificial Horizon. Directional Gyro, and Autopilots 241

7 xj v Contents Single-Pilot IFR Operation The Prospects for Safe Personal Airplanes 16 Stability and Control Issues with Variable Sweep 16.1 The First Variable-Sweep Wings - Rotation and Translation The Rotation-Only Breakthrough The F-111 Aardvark, or TFX The F-14 Tomcat The Rockwell B-l The Oblique or Skewed Wing Other Variable-Sweep Projects Modern Canard Configurations Burt Rutan and the Modern Canard Airplane Canard Configuration Stall Characteristics Directional Stability and Control of Canard Airplanes The Penalty of Wing Sweepback on Low Subsonic Airplanes Canard Airplane Spin Recovery Other Canard Drawbacks Pusher Propeller Problems The Special Case of the Voyager Modern Canard Tactical Airplanes Evolution of the Equations of Motion Euler and Hamilton Linearization Early Numerical Work Glauert's and Later Nondimensional Forms Rotary Derivatives Stability Boundaries Wind, Body, Stability, and Principal Axes Laplace Transforms, Frequency Response, and Root Locus The Modes of Airplane Motion Literal Approximations to the Modes Time Vector Analysis Vector, Dyadic, Matrix, and Tensor Forms Atmospheric Models Integration Methods and Closed Forms Steady-State Solutions Equations of Motion Extension to Suborbital Flight Heading Angular Velocity Correction and Initialization Suborbital Flight Mechanics Additional Special Forms of the Equations of Motion The Elastic Airplane Aeroelasticity and Stability and Control Wing Torsional Divergence

8 xv 19.3 The Semirigid Approach to Wing Torsional Divergence The Effect of Wing Sweep on Torsional Divergence Aileron-Reversal Theories Aileron-Reversal Flight Experiences Spoiler Ailerons Reduce Wing Twisting in Rolls Aeroelastic Effects on Static Longitudinal Stability Stabilizer Twist and Speed Stability Dihedral Effect of a Flexible Wing Finite-Element or Panel Methods in Quasi-Static Aeroelasticity Aeroelastically Corrected Stability Derivatives Mean and Structural Axes Normal Mode Analysis Quasi-Rigid Equations Control System Coupling with Elastic Modes Reduced-Order Elastic Airplane Models Second-Order Elastic Airplane Models Concluding Remarks Stability Augmentation The Essence of Stability Augmentation Automatic Pilots in History The Systems Concept Frequency Methods of Analysis Early Experiments in Stability Augmentation The Boeing B-47 Yaw Damper The Northrop YB-49 Yaw Damper The Northrop F-89 Sideslip Stability Augmentor Root Locus Methods of Analysis Transfer-Function Numerators Transfer-Function Dipoles Command Augmentation Systems Roll-Ratcheting Superaugmentation, or Augmentation for Unstable Airplanes Propulsion-Controlled Aircraft The Advent of Digital Stability Augmentation Practical Problems with Digital Systems Tine Domain and Linear Quadratic Optimization Linear Quadratic Gaussian Control lers Failed Applications of Optimal Control Robust Controllers, Adaptive Systems Robust Controllers, Singular Value Analysis Decoupled Controls Integrated Thrust Modulation and Vectoring Concluding Remarks 322

9 xvj Contents 21 Flying Qualities Research Moves with the Times Empirical Approaches to Pilot-Induced Oscillations Compensatory Operation and Model Categories Crossover Model Pilot Equalization for the Crossover Model Algorithmic (Linear Optimal Control) Model The Crossover Model and Pilot-Induced Oscillations Gibson Approach Neal-Smith Approach Bandwidth-Phase Delay Criteria Landing Approach and Turn Studies Implications for Modern Transport Airplanes Concluding Remarks Challenge of Stealth Aerodynamics Faceted Airframe Issues Parallel-Line Planform Issues Shielded Vertical Tails and Leading-Edge Flaps Fighters Without Vertical Tails Very Large Aircraft The Effect of Higher Wing Loadings The Effect of Folding Wings Altitude Response During Landing Approach Longitudinal Dynamics Roll Response of Large Airplanes Large Airplanes with Reduced-Static Longitudinal Stability Large Supersonic Airplanes Concluding Remarks Work Still to Be Done 345 Short Biographies of Some Stability and Control Figures 347 References and Core Bibliography 357 Index 377