CONTENTS

CONTENTS

PREFACE ……………...2

INTRODUCTION ………………8

BASIC AERODYNAMICS….8

Aircraft reference axes

The source of aerodynamic loads

Lift production Aerodynamic drag

Aerodynamic pitching moments

The flight envelope

DESIGN AND REQUIREMENTS OF COMBAT AIRCRAFT ….21

Preliminary design

The requirements of combat aircraft

Classification of combat aircraft

CHAPTER 1: WING DESIGN……..26

INTRODUCTION…..26

AEROFOIL SECTIONS…..26

Terminology

Aerofoil thickness

Shock stall

Advanced and supercritical sections

Camber

Wing twist

WING PLANFORM…..37

Aspect ratio

Wing size

Wing tip shape

Taper ratio

SWEPT WINGS….42

The birth of sweepback

The benefits of sweepback

The penalties of sweepback

DELTA WINGS….52

The birth of the delta planform

Advantages of the delta as seen in the 1950s

Disadvantages of the delta

Artificial stability leads to the renaissance of the delta

Compound-sweep deltas

VARIABLE-SWEEP WINGS….. 63

Variable sweep leaves the nest

Mission requirements demanding variable sweep

The fundamental drawback: excessive longitudinal stability

Sweep control

Features specific to variable-sweep aircraft

The weight penalty of variable sweep

FORWARD-SWEPT WINGS…. 72

Aeroelastic tailoring

Advantages of forward sweep

HIGH-LIFT DEVICES ….75

The need

Leading-edge devices

Trailing-edge flaps

Sizing of high-lift devices

MANOEUVRABILITY….82

The requirements

The flow over swept wings

Buffeting

Lateral/directional instability

Improving the high-AOA characteristics of the basic wing

LATERAL CONTROL…97

Rolling motion of an aircraft

Rolling performance requirements

Ailerons

Spoilers

Differential tailplanes

DIHEDRAL, ANHEDRAL AND VERTICAL WING POSITION….102

Lateral stability

Dihedral and anhedral

Vertical wing position

Combined effects

Other design factors influencing wing position

"AERODYNAMIC CRUTCHES"……….106

Wing fences

Sawteeth

Notches

Vortex generators

CHAPTER 2: AIR INTAKES……..110

INTRODUCTION…..110

THE FUNCTION AND IMPORTANCE OF AIR INTAKES…….110

INTAKE DESIGN CRITERIA……111

Total pressure recovery

Distortion

Dynamic distortion

Spillage drag or cowl lip suction?

Boundary-layer diverter and bleed drag

Intake buzz and bypass drag

Flight and operational safety

INTAKE DESIGN FEATURES….114

Intake size

Cowl lip shape:

fixed profile, variable-radius inlet, suck-in doors

Intake shape

Sideplates

Intake boundary-layer management

Engine bypass systems

Intake duct length and shape

INTAKE LOCATION….123

Nose intakes, wing-root leading-edge intakes, side intakes, shielded side intakes, ventral intakes, dorsal intakes, underwing intakes

INTAKE TYPE….128

Compression surfaces

External versus external/internal intakes

SUPERSONIC VARIABLE-GEOMETRY INTAKES…..132

Contribution to pressure recovery Mass-flow control:

Intake behaviour as mass flow is varied Intake buzz

Coping with mass-flow variations

Means of varying inlet capture area

Variable geometry for high-AOA flight

ENGINES….138

Engine location

Engine number

Engine type

CHAPTER 3: FUSELAGE DESIGN…..141

INTRODUCTION….141

NOSE AND FORWARD FUSELAGE…..141

Forebody shaping:

Forward camber

Forebody length and shape with

reference to high-AOA flight

Nose shape as influenced by radar and

laser-ranging installations

Crew accommodation influences

CENTRE FUSELAGE…..148

Volume requirements

Wing/body blending

The Area Rule:

The Supersonic Area

Rule Differential area-ruling

Applications of the area rule

REAR FUSELAGE….162

Fuselage length

CHAPTER 4: TAILPLANES (HORIZONTAL STABILISERS)…..162

INTRODUCTION….162

THE FUNCTION OF TAILPLANES….162

Longitudinal stability

Stability margins

TAILPLANE SIZING…..164

Limiting CG positions

Trim drag

INFLUENCES ON TAIL EFFECTIVENESS…..166

Downwash

Compressibility effects

Aeroelastic effects

Store wake and forebody effects

TAILPLANE LOCATION….168

Vertical position Fore-and-aft position

TAILPLANE SHAPE….172

THE ALL-MOVING TAILPLANE…..173

A historical perspective

CONTROL-CONFIGURED VEHICLES….175

Active control technology Stability augmentation and relaxed static stability

FOREPLANES….180

Attractions of the canard layout

Adverse effects of the foreplane

Recent applications

Artificial stability and the foreplane

CHAPTER 5: FINS (VERTICAL STABILISERS)…..185

INTRODUCTION…..185

THE FUNCTION AND SIZING OF FINS …..185

The need Fin area requirements

INFLUENCES ON FIN EFFECTIVENESS…..190

Compressibility effects

Flight at high AOA

FIN POSITION AND SHAPE……..195

Location (fore and aft) Fin shape Ventral fins or strakes

RUDDERS….198

Design factors

CHAPTER 6: EXHAUST NOZZLES AND AFT-BODY SHAPE…..201

INTRODUCTION…..201

CONVERGENT NOZZLES…..201

CONVERGENT-DIVERGENT NOZZLES…..202

The need for a diverging section

Evolution of the convergent-divergent nozzle:

Ejector nozzles

Variable-geometry con-di nozzles

THRUST VECTORING….207

Thrust reversers

Thrust vectoring in flight

Two-dimensional thrust-vectoring nozzles

AFT-BODY SHAPE….211

Tail-end design

REFERENCES …..219

INDEX….221