Cyclic & Collective By Shawn Coyle Www.eagleeyesolutionsllc.com

Why Two “Books”? Why Did I Write This Book? Keeping Things in Perspective

Standard Disclaimers Political Correctness Aim of every flight

Terms Used Dedication

Introduction to the Second Edition Corrections and Additions

1

iii iv iv

iv iv iv

v v

v vi

General Axes of the Blades How Lift Gets to the Hub Drag on the Whole Blade Blade Flapping A Brief Moment to Study Law

1

Telling the Blades Apart Airframe Relative Airspeed

Vectors

1

Newton’s Laws

1

Relative Airflow and Disk

1 1 2

Cyclical Change of Pitch

2

Total Lift from the Disk

Newton’s First Law Newton’s Second Law Newton’s Third Law

Other Physics and Maths terms Momentum and Inertia Speed Velocity Acceleration Equilibrium

Vectors, Resultants and Resolving Moments and Couples

2 2 2 2 2

3 3

Moments Couple

3 4

Balance of Forces

4

Dimensional Correctness Distance and Time

4 4

Mass, Force, Energy and Work

4

Mass Force Energy Work Power

Graphs and Such Putting Together Some of the Basics

4 5 5 6 6

6 7

2

Introduction to Helicopter Aerodynamics Terms Used Zero Airspeed vs. Zero Groundspeed Hover Center of Gravity (CG) Aerodynamic Terms Angle of Attack Lift

11 11 11 11 14 17

More Discussion of Lift

19

Formula for Lift Drag Zero Angle of Attack

20 21 22

25 25 26 27 27 29

4 More Basics of the Helicopter Generic Helicopter The Whole Rotor

Some Fundamentals

Math and Physics Revisited

3 The Rotor Blade

Forward Flight and Dissymmetry of Lift Flapping to Equality Tip Path Plane

Drag at Different Parts of the Disk Total Drag on the Disk Keeping the Blades Clean

Flapback or Blowback Rotor Heads and Components Fully Articulated Rotor Hub

Control of the Rotor The Swashplate Phasing of Control Inputs Rotating Scissors Assembly So What?

Tail Rotors Anti-Torque Control

31 31 31 32

33 33

34 35

36 36

37 37 37

38 38 38

39 39 39 41 41

41 41

5 Air, Wind and Weather Introduction What Temperature is That? Where do we Measure Vertical Distance From?

International Standard Atmosphere Standard Day Pressure Altitude Non-Standard Day Density Altitude Importance of Understanding Density Altitude The How and Why of Density Altitude Relative Humidity

Wrong Information More Wrong Information Wind! Knowing The Wind from Natural Sources Wind Speed Change with Height Wind Direction Change with Height

43 43 43

43 43 43 44 44 45 46 46

47 47 48 48 49 50

ix

Wind Shift and Turbulence A Lesson from the Birds

Weather So What do We Need to Worry About? An Example

50 50

50 51 51

6 Basic Helicopter Performance 53 53

Measuring Performance

53

Out of Ground Effect (OGE) In Ground Effect (IGE) How Does Ground Effect Happen? Using a Crane to Lift Instead of an Engine

Power Required vs. Density Altitude Hover Ceilings

Forward Flight Performance Power Required vs. Airspeed What You Can’t Do with This Chart The ‘Backside’ of the Power Curve

Low Airspeed Power Required Climb and Descent Performance - Simplified Flight Manual Charts

V Airspeeds Load Factors

53 54 54 54 55

56 56

56 56 57 57

58 59 59

59 60

7 Balance and Weight The Importance of Center of Gravity Calculating Weight and Balance

Balance Datum Forward of the Nose. Datum At Rotor Mast

Weight and CG Diagram Weight vs. Loaded Moment Method Yet Another Way to Measure CG Longitudinal CG Lateral CG Vertical CG

Balance of Forces General

Balance of Forces in the Hover Side View Four Basic Forces Top View Balance of Forces - Torque Reaction Rear View of Balance of Forces

Trim Balance of Forces - Forward Flight Side View of Balance of Forces Top View of Balance of Forces Forward Flight Inherent Sideslip Rear View of Balance of Forces - Forward Flight

x

The Autorotation

Aerodynamics

Introduction Autorotation Defined

61 62

62 63 64

65 65 65 66 66 67

68 68

69 69 69 69

71 71 72 72 73 73

of 75 75

Conditions Necessary for Autorotation

Introduction Airframe Performance Defined Hover performance

8

Lift Vectors Again Effect of Forward Flight

75

76 78

How the Blade Works in Autorotation NR in Autorotation Descent

78 78

Another Use for the Autorotation RPM Chart Effect of Density Effect of Weight

79 79 79

9 Instruments and Warning Systems Airframe Instruments Sideslip and Side Force

81 81

What the Slip Ball Measures What is Sideslip? Slip Strings

Engine Transmission and Rotor Instruments

81 82 84

84

NR Warnings

84

Transmissions and Gearboxes Transmission Oil Temperature and Pressure Chip Detectors

85 85 85

10

The Piston Engine

Introduction Principles of Operation Components

Basics of Carburation Vaporization

Piston Engine Helicopter Instruments Manifold Pressure

Starting Clutches

87 87 87

88 89

89 90

91 91

Centrifugal (or Automatic) Clutch Idler or Manual Clutch

91 91

Free–Wheel Units Piston–Engine Helicopter Power Control

92 92

Rotor RPM

Power Output Measuring Piston Engine Helicopter Power Same Engine in a Seized Wing Airplane

Carburetor Icing Why do Carburetors Ice Up? More Carburetor Icing Explanation Effects of Icing Symptoms of Carburetor Icing Carburetor Heat Prevention of Carburetor Ice

92

92 93 93

94 94 94 95 95 96 97

Mixture Control Throttle Handling Over-Pitching

97 98 98

Wrong Side of Torque Curve Only on Some Piston Engine Helicopters Coning Angle and Over-pitching Turbine Engines and Over-Pitching

Throttle Co–relators Fuel Injection Piston Engine Governors

99 99 99 100

100 100 101

How Does the Governor Work?

101

Performance Rules of Thumb for Piston Engines 101 Turbochargers 101 Other Components of the Engine 102 Oil and Oil Pumps Generators Fans Fuel Systems

102 102 102 102

Operation of the Piston Engine

103

Pre-Start Fuel Draining Starting Lift-Off In-Flight

103 103 103 103 104

11

Dear Student

Instructors - What They Know and Don’t Know Personality Differences The Essential Pre-Flight Briefing Checklists For Those Who Make Checklists

All Those Gages and Clocks!

105 105 106 106 106

106

Blindfold Cockpit Checks

106

For Both Instructor and Student

107

Transfer of Control Following Through on the Controls

Where to Look

107

Outside, Mostly Look Around Collision Course

107 108 108

Post-flight

108

Walkaround

12

107 107

108

Before You Strap In…

Introduction Prior to Lift-off Terms Used Pre-Flight Actions Pre-Flight checks Walk-Around checks Start–Up checks

109 109 109 110 110 110 111

Energy and the Rotor System Pre-Lift-off Checks

Holding the Controls Light Training Helicopters Control Pressure, Not Control Movement Function of Controls

Effects of Controls Downwash Hand Signals

13

111 111

112 112 112 112

113 114 114

Helicopter Flying - The Basics

General Introduction Forward Flight

Effects of Controls in Forward Flight Cyclic stick Collective lever Pedals

Summary of Effects of Controls Attitude Flying Cruise

117

117 117 118 118

119 119 120

Changing Airspeed in Level Flight Smooth Airspeed Changes Back Side of The Power Curve Two Airspeeds for the Same Power!

Climbs and Descents Turns A Note Gentle Turns (up to 20 Angle of Bank) Nose Drop Increased Power A Changed Sight Picture Slip Ball Practice Medium Turns (20 to 45 Angle of Bank) Steep Turns (Greater than 45 Angle of Bank)

Developing a ‘Seat of the Pants’ Sense

14

117

121 121 122 122

122 123 123 123 123 123 123 124 124 124 124

124

The Divine Art of Hovering

Introduction To the Hover! Hovering More Easily Vertical References Aim of Hovering

Concepts of Hovering Hover - Zero Groundspeed vs. Zero Airspeed Effects of Controls - Hover and Low Airspeed Forward Flight and ‘Low Airspeed’ Overcontrolling in the Hover Cyclic Stick as a Position Controller

125 125 125 125 126

126 126 126 127 128 129

NR Control

130

Hovering With A Purpose

130

Partial Control Technique

130

xi

Lots of Things to Do

Specific Exercises for Learning Hovering Taxing Along a Line Changing Height While Hovering Changing Heading

Moving Around Hovering with Different References Back to Flying

130

131 131 131 132

132 132 132

Turns in the Hover

133

No Wind With Winds

133 133

In the Low Speed Environment

134

Useful Training Exercises General Handling in the Hover

134 135

Taxing to the Side or Rear Ground Taxing Skid Helicopters

136 136

15

‘Twixt Heaven and Earth,

Introduction

137

Slipping and Crabbing Transition to Forward Flight Ground Track Translational Lift

137 137 138 138

Other Transitions to Forward Flight

138

Cushion Creep Steep Climbout

Running Takeoff Why Running Takeoffs? How It Works How to Carry Out a Running Takeoff Cautions on the Running Takeoff

“Maximum Performance Climbout” An Example of Getting Caught

Downwind Transition Turns After Transition Approach and Touchdowns Transition Back to the Hover

Learning to Judge… …Perspective …Rates of Closure

‘Normal’ Approach Suitable Rate of Descent Adding Power

Fast Approaches Steep Approach The No-Hover Touch Down Downwind Approach to the Hover

Approaches with Turns

139 139

139 139 139 140 140

140 140

What do Traffic Patterns Teach / Show

Confined Areas

Touching Down From The Hover Flat Surfaces Don’t Overcontrol A Neat Trick for Smooth Touch Downs

Sloping Surfaces

144 144

145 145 145 146

146 146 146

VIP Approaches - Mastery of the Machine

146

151 151 152 152 153

153 153 154 154

155

Tail Rotor Side Thrust While You’re On the Sloping Ground Wind Across the Slope Lift-off from the Slope Nose Upslope / Downslope

156 156 157 157 157

One Last Word About Sloping Ground

157

17

Introducing Emergencies

Emergencies - General Critical Emergencies Dual Concurrence (or Double Checking)

159 159 159

What Emergencies Can Happen

160

Unanticipated Emergencies As a Student Chip Detectors Realistic Emergencies Where to Handle Emergencies

160 160 160 160 161

General

144

151

Flat Pitch to Light on the Skids How Do you Know ’Light on the Skids’? From ’Light on the Skids’ to the Hover Airborne! Lift-off out of Wind

18

143 144

148

Lift-off and Touchdown

Introduction

142

142

147 147 148

16

141 141 141

Line-Up Turning into a Downwind Approach

xii

Running Landing Traffic Patterns or Circuits

Engine Failures for Beginners

Simulated vs. ‘Real’ Engine Failures Warming-up for Autorotations Vertical Landings

Engine Failures in the Hover Judging Collective Lever Application High Hover Engine Failures Self-Initiated Engine Failures Hover Quick Stops The Flare So What Should You Do? Flare Effectiveness

Collective Check - Why It Works Coupling of Forces in Leveling Helicopter

Power Recovery Autorotations Getting Back to the Hover

163 163 163 164

164 164 165 165 165 166 167 167

168 168

168 169

‘Real’ Autorotations Eyes Out of the Cockpit!

170 170

Autorotative Performance

171

Some Final words

171

Some Words on The Height-Velocity Curve

19

171

Is it a Limit Because Its in the Limitations Section? 189 Power Ratings and Limitations 190

The Military Flight Manual Visual Flight Rules (VFR)

190 190

V Speeds

Peculiarities of the Helicopter

Introduction Loss of Translational Lift Vortex Ring State Impossible Descent Conditions Not Just in Descent Demonstrating Incipient Vortex Ring State Uncommanded Attitude Changes Making the Situation Worse Recovery Wrong Advice The Why of Vortex Ring State Why The Symptoms?

Rollover Static Rollover Dynamic Rollover Dynamic Rollover on Landing Dynamic Rollover on Takeoff Action in Event of Dynamic Rollover

Retreating Blade Stall

173 173 174 175 175 175 176 176 176 176 177 177

177 178 178 179 179 180

180

Symptoms

181

Blade Sailing

181

20

Flight Manuals, Rules and Regulations Why? The Civilian Flight Manual Sections of the FM Emergency Definitions Notes, Cautions and Warnings Procedural Words Performance Data No Altimeter Correction Charts Flight Manual Supplements (FMS) Weight and Balance Information Manufacturer’s Data Individualized Copy of the FM

183 183 183 184 184 185 185 185 185 186 186 186

Some Philosophical Words about the Civilian FM 186 More Philosophy… 187 Certification Basis

Reasons for Rules

187

188

Two more Pet Peeves

188

Reasons for Limitations

188

Another Way of Thinking About Limitations

Side Wind, Sideward Flight and All That

189

189

21

191

Miscellaneous

Where the Pilot Sits Radios and Air Traffic Control Negative Radio

Safety Statistics Ground Handling Wheels

Safety for Others Going Solo Cross Country Flying Single Seat and Ultralight helicopters

193 193 193

194 194

194 194 195 195

Inexperienced Pilots Shouldn’t Be Flying Them 195 Get A Private Pilot’s License First 196 Get Experience in Several Different Types 196

General Words of Advice Shutdown

196 196

22 For the Professional Helicopter

Pilot / Instructor

For the Professional Helicopter Pilot Helicopter Pilots Are Different Legal Implications Maintenance Service Difficulty Reports (SDRs) Your Part in Safety Experience Care and Feeding of Passengers / Customers

Make a Decision Philosophy of Instruction Measuring or Predicting Pilot Performance More Philosophy Preflight Briefing Preflight Inspection Walkaround

Concepts of Controls Cyclic Collective Throttle Pedals

Looking Outside

199 199 199 199 200 200 200 200

200 201 201 201 202 202 202

202 202 202 202 202

202

Limitations

203

Following Through Checklists Questions and Tests

203 203 203

When the Students Ask Questions

203

xiii

What are you Really Trying to Teach? Even More Philosophy Specific Exercises Trusting the Student Space Awareness

Flying by the Seat of the Pants Written Tests

203 203 204 204 204

204 205

23

Advanced Helicopter

Review

207

Aerodynamics Hover Review of Lift and Drag

Airfoils Non-symmetrical Airfoils Lift and Drag Lift to Drag Ratio Changing NR Changing Density Altitude

207 207

207 207 207 208 208 208

209

Blade CG location AoA Changes due to Flapping AoA, Lift and Center of Pressure

209 209 210

Symmetric Section Non-symmetric Section Why the Fuss about Pitching Moments?

Blades Blade Root Cutout Blade Tip Shapes Twist Taper Twist and Taper - Again Lift to Drag Ratio Again

Disk Aerodynamics

211 211 212 212

212 212 213 213 213 213 214

214

Solidity Why 2 Blades May be More Efficient than 4 AoA and the Disk Advance Ratio VNE and True Airspeed

214 215 215 215 216

Retreating Blade Stall Again Coning Angle Again Transverse Flow Effect or Inflow Roll Stick Migration

216 216 216 217

Tail Rotors Location on Fuselage Size, Direction of Rotation Aerodynamics of the Tail Rotor

218 218 218 219

24Flight Controls and Rotor Heads General Tip Anhedral

xiv

Rotor Heads Lead–Lag Dampers Types of Drag Dampers Droop Stops / Flap Restrainers Droop Stop Pounding Lubrication

221 221

Hinges

226 226 226

227

Flapping Hinge Offset Hinge Arrangements Delta–Three Hinges Elastomeric Bearings Hingeless Rotor Heads

New Rotor Heads The Teetering Rotor Head Stabilizer Bars Flap or Hub Restraining Springs

Hiller Control System Robinson R-22 and R-44 Hub. MD Series Rotor Head Height of Hub Above the CG Blade Lag Angle Negative Pitch

227 228 228 229 229

230 230 231 232

233 233 233 233 233 234

Advanced Performance

General Factors Affecting Performance Power Loading

Induced Velocity Mach Number Effects Hover Performance and Altitude Surface Effect on Hover Performance Vertical Drag Another Look at Hover Performance

Typical Civil FM Performance chart Level Flight Performance Indicated Airspeed and True Airspeed Collective Angle vs. Airspeed Power vs. Collective Angle

Peculiarities of Low Airspeed IGE Another Look at Power Required to Hover Rotor Efficiency Ground Vortex Roll Up Low Airspeed Power Required - Again

Range

223 223 224 224 225

225

Shaft Axis Control Axis Yet Another Disk Axis

25

221 221 221 222

223

Disk Axes

Blade and Segment Aerodynamics

Pitching Moments

Blade Inertia More Reasons for Lead–Lag Motion Hook’s Joint Effect Other Phase Angles

235 235 235

236 237 237 237 238 238

239 240 240 240 240

241 241 242 242 243

244

Range Improvements with Altitude Headwind and Tailwind Effects Point of No Return Equal Time Point What If Something Goes Wrong?

Endurance

249

Radius of Action How to Trick A Navigation System Payload vs. Radius of Action

Climb and Descent Performance Climbs Best Angle of Climb Airspeed Descent Performance

Whizz Wheels Rules of Thumb

26

246 246 247 248 249 250 250 251

251 252 252 253

253 254

Other Components

General Fuel Systems Fuel Valves Fuel Pumps Low Fuel Warning Systems Other Parts of the Fuel System When is the Fuel Gauge Reading Correctly? Pounds or Gallons? Fuel Quality Fuel Drains and Living in the Field Fuel Jettison

257 257 257 257 257 258 258 258 258 259 260

Transmissions and Drive Shafts HUMS Electrical Systems

260 261 261

External Power Generators Batteries DC–Based Electrical Systems AC–Based Electrical Systems Electrical Failures Circuit Breakers When a Circuit Breaker ‘Pops’

261 261 262 262 262 263 263 264

Hydraulic Systems Reasons For Hydraulics Typical Hydraulic System Unpressurized Reservoirs Hydraulic Emergencies

De-Ice / Anti-Ice systems De-Ice vs. Anti-Ice

Landing Gear General Skids Wheeled Undercarriage Retractable Landing Gear Off-level Landings Wheel Brakes

264 264 264 265 265

265 266

266 266 266 266 268 268 268

Skis Full Length Skis Bear Paw Skis Skis on Mud

268 269 269 269

Floats

269

Fixed Floats Boating! Start-up / shutdown Spray Taxing on Water Liftoff and Touchdown from the Water Following the Waves Off-Level Touchdowns on Water Lift-off and Touchdown from the Ground Other Effects of Fixed Floats Emergency Floats Use and Problems

Fire Detection and Suppression Heating and Ventilation Seats Compasses Windshield Wipers

27

269 269 269 270 270 270 270 270 270 271 271 271

271 272 272 272 273

Advanced Helicopter Flying

So How Do We Fly a Helicopter?

275

Driving a Car Explained Compensation

275 275

Flying a Helicopter – Hovering

276

Cruising Flight Example Other Cue–Related Problems

276 277

Why are Helicopters Difficult to Fly?

277

Slow Response Explained Cross Coupling Different Responses from the Pedals

278 279 279

How to Hold the Controls

279

Cyclic Overcontrolling Collective Pedals

279 280 280 280

Helicopter Pilots are Easy… Artificial Control Feel or Trim Systems

Control Forces

284 284 284

The Other Way ‘Round

284

More Instruments

Pitot Systems Altimeters

Corrections to the Altimeter in Cold Weather Static Port Locations

281

282

Collective Release Fuselage Attitudes Pedals Again

28

280

287 288

288 289

xv

So What?

289

What Can be Done About This? LORAS (LOw aiRspeed System) LASSIE RAH-66 Commanche System General Comment on Low Airspeed Systems

290 290 290 290 290

Another Reason for Low Airspeed Systems Miscellaneous Instruments

291 292

Outside Air Temperature Gages Radar Altimeters Waves and Radar Altimeter Vertical Gyroscopes and Attitude Indicators

292 292 292 292

Entering the Digital Era

293

Too Much Accuracy But Some Good News Too...

29

The Turbine Engine

Introduction Turbine Engines are Different! Typical Free Turbine Engine Ratings and Limitations of Engines Difference between Ratings and Limitations How Long is Each Limit Good For? Cycles Measuring Temperature

Density Altitude vs. Pressure Altitude and OAT Less Power in Cold Temperatures Effect of Humidity on Turbine Performance Compressor Stalls Two Correct Answers Don’t Make a Third… Turbine Engine Instruments Torquemeters Use of the Torquemeter

Governing systems Reasons for Installing Governors Droop! Static Droop Oscillating Governors and Hysteresis Transient Droop Hydro–mechanical Governors

Electronic Fuel Controls FADEC What Has All This Got to Do With FADECs? Failures of Digital Fuel Controls Practical Benefits of FADEC Change of the Pilots Point of View Duplication of Sensors Some Improvements Possible? Manual Control of the Turbine Engine Question Time Tail Rotors, Governors and Free Drinks Differences from Piston Engine Transient Overtorques

xvi

293 293

295 295 295 297 297 297 297 297

297 299 299 300 300 301 302 304

304 305 305 306 307 307 308

309 309 309 310 311 311 311 311 311 312 312 312 312

Turbine Engine Power Monitoring Topping Checks Trend Monitoring Checks

Automatic Relight vs. Manual Air Starts Engine–Related Items Intake Protection Systems Anti-Icing vs. De-Icing Bleed Air Systems Bleed valves Heaters Air Conditioning Performance Effects of Bleed Air Systems Starting Against the Rotor Brake

Turbine Engine Cool-Down Emergency Systems

Fixed Shaft Turbine Engines

30

313 314 314

315 316 316 316 316 317 317 317 317 318

318 319

319

Advanced Engine Failures

General Autorotations Sensory Deprived, Multi-Variable Maneuver The Big Picture

Where to Practice Autorotative Landings Pre-Nominate the Landing Spot Autorotations ‘En–Route’

Closer Look of Autorotative Performance Energy and Autorotations Cone of Possible Areas Variations on the Theme

321 321 321 321

322 323 323

323 325 326 326

Zero–Airspeed Autorotations 326 Reverse Cone of Energy 327 Landing Site is Straight Ahead 328 Three Basic Locations 329 Kinetic Energy in the Flare 330 Why Try the Variations? 331 Other Situations with Respect to the Landing Spot 332 Combinations! 333

Intervention Delay Time Run-Down Time of the Engine

Height Velocity (HV) Curves Ignoring A Part of Most HV Curves So What’s Missing about the HV Curve? Development of the HV Curve Miscellaneous Points About the HV Curve Another Type of Autorotation

333 334

334 335 335 336 337 337

31 Advanced Emergencies General Tail Rotor Problems Loss of Thrust Loss of Thrust in the Hover

339 339 339 340

Loss of Thrust in Forward Flight Loss of Control of Tail Rotor Thrust Diagnosis of the Situation Slip Ball Just Touching Right Side Slip Ball Fully Against Right Side Slip Ball Just to the Right of Center

Fires

342

Fires in the Cockpit

Not All Emergencies are in the Book Some Emergencies have Other Implications

When to Inflate Pop-out Floats To Those Who Write Emergency Procedures Emergencies Caused by Vibrations and Noise

32

340 340 340 341 341 341 342

342 342

342 343 343

Multi-Engine Helicopters

General Introduction Terms Other Differences Why are AEO and OEI Limits Different? Power Matching - Non–FADEC Engines Left Side vs. Right Side

OEI Performance

345 345 346 346 347 348

349

Level Flight Best Angle of Climb Airspeed (Again)

349 350

Engine Failures in Multi-Engine Helicopters

351

Engine–Related Emergencies Training Mode In FADEC Engines

Category A or Category B? Common Points About Category A Using Everything You’ve Got Different Profiles Approach and Landings Use of Contingency Power General Criteria for Takeoff Techniques

Heliport Takeoff Techniques Vertical Climb Back-Up Technique ‘Sideways Slide’ Technique Where to Practice Single Engine Techniques

351 353

353 354 355 355 356 357 357

357 357 358 358 358

33

Stability and Control of the Helicopter Weight and Balance Weight and CG Calculations Weight and Balance Effects

361 361 362

Inherent Sideslip Cross–Coupling of CG Effects Keel Area Ratio, or Weathercock Effect Fixed Floats Effect on Stability and Control Flight Controls

363 363 364 364 365

Friction Systems on Cockpit Controls

365

Viscous Damping of Control Systems Control Mixing

Equations of Motion Control Margin / Limitations on Controls Head and Mast Bending Moments Longitudinal Cyclic Forward Cyclic Aft Cyclic Lateral Cyclic Up Collective Down Collective Tail Rotor

Lesser Known Effects Cross–Coupling Lock Number Rotor Head Type Effect on CG Range

Solving Aerodynamic Problems Wings Rudders Horizontal Stabilizers Vertical Stabilizers End Plates Gurney Flaps and Blunt Trailing Edges Tail Boom Strakes More Aerodynamic Fixes

How We Control the Helicopter

365 366

366 366 366 367 367 367 367 367 367 368

368 368 368 369

369 369 370 370 370 370 370 371 371

371

34

Further Peculiarities of The Helicopter Introduction Vibrations Types Of Vibrations Determining The Type of Vibration Sources Solutions to Vibrations Solving Track and Balance Problems

Ground Resonance On Start-up Resonance During Landings or Takeoff

Tail Rotor Control

373 373 373 373 374 376 378

378 379 380

380

Loss of Tail Rotor Effectiveness

381

Wingovers or Crop Duster Turns Rapid Rolling Underslung Loads

382 385 385

Knowing How Much it Weighs Why No Cargo Hook Weighing Devices? Watching the Load Problems CRAP Method of Load Obedience Weird Underslung Loads Flight Path Planning Emergencies With Underslung Loads Training For Underslung Loads

385 386 386 387 387 387 388 388 388

xvii

Automatic Flight Control Systems and Underslung Loads 388 Uncommanded Jettison of Underslung Loads 389

High Altitude Flying Icing Why is Icing So Bad?

Snow Flying in Your Own Dust Mast Bumping Causes for Mast Bumping Too Much Sideslip Other Causes of Mast Bumping What to Do In the Event of Mast Bumping Training to Prevent Mast Bumping

Design Eye Point

35

390

391 391 391 392 393 393 393 393

394

Other Helicopter Types

Brief history

395

Coaxial Tandem Synchrocopter or Intermeshing Rotors

Coanda Effect

395 396 397

398

Main Blades Tail Boom

398 398

Tip Jets Kaman Servo–Flap Controls Replacing the Tail Rotor Fenestron/Ducted Tail Rotor NOTAR

Other Types

36

389 389

398 399 400 400 401

401

Night and Instrument Flying

Introduction Night Flying Engine Failures at Night Night Vision Goggles (NVG) The Myth of Night VFR

Instrument Flying IFR Flight Envelope Why is Helicopter IFR Difficult? Disorientation Useful Instrument Flying Exercises Inadvertent IMC

Autorotations at Night, in Clouds, etc. Instrument Flying Rules (IFR) GPS and IFR Helicopter Only Approaches

37

403 403 404 404 404

405 405 405 406 406 407

407 408 408 409

Automatic Flight Control

Systems Introduction

xviii

411

Definitions

411

Why install an AFCS? Hierarchy of an AFCS AFCS and the Big Picture of Control Internal vs. External Conditions Components of An AFCS Series Actuator Parallel Actuators Combined Systems

Types of AFCS

411 412 412 413 413 415 416 417

417

Rate Damping Systems 417 Stability Augmentation System (SAS) 418 Pilot Commanded Inputs 418 Retrimming 419 Stability and Control Augmentation Systems (SCAS). 419 Attitude Based Stabilization Systems 420 Hybrid Systems 421

Automatic Trim Systems AFCS ‘Upper’ Modes Definition Problems Attitude Datum Re-Adjustment Heading Hold and Coordinated Turns

Hover and Low Speed Forward Flight In-between Airspeeds

Autopilots

422 423

423 423 423

424

Basic Autopilot. Operational Autopilot. Altitude or Height Hold Radio/Radar Altitude Hold Speed Hold in the Low Airspeed Region Programmed Maneuver Complex Helicopter AFCS Automatic Transition to the Hover Transition from Cruise to Hover Radio Coupled Operations

Advanced Concepts Side Arm Controllers

Failures of the AFCS Minimum Height for Engaged AFCS AFCS Disconnect Switches

38

421 421 422

424 424 424 425 425 425 426 427 427 428

428 428

429 429 429

Miscellaneous Musings

Type Ratings How To Survive Technical Examinations

Minimum Equipment Lists (MEL) Using GPS Intelligently How Best to Use the Magic

Myths of the Helicopter ’Tail Rotor Stall’ ‘Pendulum Effect’

431 431 431

431 432 432

433 433 433

’Stick Reversal’

Torque Limiters Health, etc. Smoking Fluids, Bodily Stress Glasses

Safety General Personal Equipment Helmets Immersion Suits

The Helicopter is Not a Winch or Bulldozer Good Examples vs. Bad Examples What Good Pilots Do

Simulators Learning to Say No

Noise

433

434 434 434 435 435 435

435 435 435 436

436 437 437

438 438

439

Definitions

1

Bibliography

xix

xx