Introduction to Flight Testing: (Aerospace Series)

Introduction to Flight Testing Introduction to Flight Testing Provides an introduction to the basic flight testing methods employed on general aviation aircraft and unmanned aerial vehicles Introduction to Flight Testing provides a concise introduction to the basic flight testing methods employed on general aviation aircraft and unmanned aerial vehicles for courses in aeronautical engineering. There is particular emphasis on the use of modern on-board instruments and inexpensive, off-the-shelf portable devices that make flight testing accessible to nearly any student. This text presents a clear articulation of standard methods for measuring aircraft performance characteristics. Topics covered include aircraft and instruments, digital data acquisition techniques, flight test planning, the standard atmosphere, uncertainty analysis, level flight performance, airspeed calibration, stall, climb and glide, take-off and landing, level turn, static and dynamic longitudinal stability, lateral-directional stability, and flight testing of unmanned aircraft systems. Unique to this book is a detailed discussion of digital data acquisition (DAQ) techniques, which are an integral part of modern flight test programs. This treatment includes discussion of the analog-to-digital conversion, sample rate, aliasing, and filtering. These critical details provide the flight test engineer with the insight needed to understand the capabilities and limitations of digital DAQ. Key features: Provides an introduction to the basic flight testing methods and instrumentation employed on general aviation aircraft and unmanned aerial vehicles. Includes examples of flight testing on general aviation aircraft such as Cirrus, Diamond, and Cessna aircraft, along with unmanned aircraft vehicles. Suitable for courses on Aircraft Flight Test Engineering. Introduction to Flight Testing provides resources and guidance for practitioners in the rapidly-developing field of drone performance flight test and the general aviation flight test community.

Table of Contents:
About the Authors xiii Series Preface xv Preface xvii Acknowledgements xxi About the Companion Website xxiii 1 Introduction 1 1.1 Case Study: Supersonic Flight in the Bell XS-1 3 1.2 Types of Flight Testing 9 1.2.1 Scientific Research 9 1.2.2 Experimental Flight Test 12 1.2.3 Developmental Test and Evaluation 14 1.2.4 Operational Test and Evaluation 14 1.2.5 Airworthiness Certification 15 1.3 Objectives and Organization of this Book 17 Nomenclature 18 Acronyms and Abbreviations 19 References 19 2 The Flight Environment: Standard Atmosphere 22 2.1 Earth’s Atmosphere 23 2.2 Standard Atmosphere Model 24 2.2.1 Hydrostatics 24 2.2.2 Gravitational Acceleration and Altitude Definitions 25 2.2.3 Temperature 26 2.2.4 Viscosity 27 2.2.5 Pressure and Density 28 2.2.6 Operationalizing the Standard Atmosphere 29 2.2.7 Comparison with Experimental Data 30 2.3 Altitudes Used in Aviation 32 Nomenclature 34 Subscripts 34 Acronyms and Abbreviations 35 References 35 3 Aircraft and Flight Test Instrumentation 36 3.1 Traditional Cockpit Instruments 36 3.1.1 Gyroscopic-Based Instruments 38 3.1.2 Pressure-Based Instruments 38 3.1.3 Outside Air Temperature 41 3.1.4 Other Instrumentation 42 3.2 Glass Cockpit Instruments 42 3.3 Flight Test Instrumentation 45 3.3.1 Global Navigation Satellite System 46 3.3.2 Accelerometers 49 3.3.3 Gyroscopes 49 3.3.4 Magnetometers 50 3.3.5 Barometer 51 3.3.6 Fusion of Sensor Data Streams 51 3.4 Summary 52 Nomenclature 54 Subscripts 54 Acronyms and Abbreviations 54 References 55 4 Data Acquisition and Analysis 56 4.1 Temporal and Spectral Analysis 56 4.2 Filtering 61 4.3 Digital Sampling: Bit Depth Resolution and Sample Rate 63 4.4 Aliasing 66 4.5 Flight Testing Example 69 4.6 Summary 69 Nomenclature 70 Subscripts 70 Acronyms and Abbreviations 70 References 71 5 Uncertainty Analysis 72 5.1 Error Theory 73 5.1.1 Types of Errors 73 5.1.2 Statistics of Random Error 76 5.1.3 Sensitivity Analysis and Uncertainty Propagation 77 5.1.4 Overall Uncertainty Estimate 79 5.1.5 Chauvenet’s Criterion for Outliers 79 5.1.6 Monte Carlo Simulation 80 5.2 Basic Error Sources in Flight Testing 81 5.2.1 Uncertainty of Flight Test Instrumentation 81 5.2.2 Example: Uncertainty in Density (Traditional Approach) 85 5.2.3 Example: Uncertainty in True Airspeed (Monte Carlo Approach) 86 Nomenclature 88 Subscripts 89 Acronyms and Abbreviations 89 References 89 6 Flight Test Planning 90 6.1 Flight Test Process 90 6.2 Risk Management 93 6.3 Case Study: Accept No Unnecessary Risk 96 6.4 Individual Flight Planning 97 6.4.1 Flight Area and Airspace 98 6.4.2 Weather and NOTAMs 99 6.4.3 Weight and Balance 100 6.4.4 Airplane Pre-Flight 103 6.5 Conclusion 105 Nomenclature 105 Acronyms and Abbreviations 105 References 105 7 Drag Polar Measurement in Level Flight 107 7.1 Theory 107 7.1.1 Drag Polar and Power Required for Level Flight 107 7.1.2 The PIW–VIW Method 112 7.1.3 Internal Combustion Engine Performance 114 7.1.4 Propeller Performance 119 7.2 Flight Testing Procedures 124 7.3 Flight Test Example: Cirrus SR20 125 Nomenclature 127 Acronyms and Abbreviations 129 References 129 8 Airspeed Calibration 132 8.1 Theory 132 8.1.1 True Airspeed 134 8.1.2 Equivalent Airspeed 134 8.1.3 Calibrated Airspeed 135 8.1.4 Indicated Airspeed 137 8.1.5 Summary 137 8.2 Measurement Errors 138 8.2.1 Instrument Error 138 8.2.2 System Lag 138 8.2.3 Position Error 139 8.3 Airspeed Calibration Methods 142 8.3.1 Boom-Mounted Probes 143 8.3.2 Trailing Devices and Pacer Aircraft 143 8.3.3 Ground-Based Methods 145 8.3.4 Global Positioning System Method 145 8.4 Flight Testing Procedures 147 8.5 Flight Test Example: Cirrus SR20 148 Nomenclature 150 Subscripts 151 Acronyms and Abbreviations 151 References 151 9 Climb Performance and Level Acceleration to Measure Excess Power 153 9.1 Theory 153 9.1.1 Steady Climbs 154 9.1.2 Energy Methods 160 9.2 Flight Testing Procedures 165 9.2.1 Direct Measurement of Rate of Climb 165 9.2.2 Measurement of Level Acceleration 166 9.3 Data Analysis 167 9.4 Flight Test Example: Cirrus SR20 168 Nomenclature 172 Subscripts 173 Acronyms and Abbreviations 173 References 174 10 Glide Speed and Distance 175 10.1 Theory 176 10.1.1 Drag Polar 176 10.1.2 Gliding Flight 179 10.1.3 Glide Hodograph 180 10.1.4 Best Glide Condition 181 10.2 Flight Testing Procedures 183 10.3 Data Analysis 185 10.4 Flight Test Example: Cirrus SR20 186 Nomenclature 188 Subscripts 188 Acronyms and Abbreviations 189 References 189 11 Takeoff and Landing 190 11.1 Theory 190 11.1.1 Takeoff Ground Roll 191 11.1.2 Landing Ground Roll 193 11.1.3 Rotation Distance 194 11.1.4 Transition Distance 194 11.1.5 Climb Distance 195 11.1.6 Total Takeoff and Landing Distances 195 11.1.7 Simple Estimations 195 11.2 Measurement Methods 196 11.3 Flight Testing Procedures 197 11.3.1 Standard Flight Procedures 197 11.3.2 Flight Test Procedures 199 11.3.3 Data Acquisition 200 11.3.4 Data Analysis 200 11.4 Flight Test Example: Cessna R182 201 Nomenclature 202 Subscripts 203 Acronyms and Abbreviations 204 References 204 12 Stall Speed 205 12.1 Theory 206 12.1.1 Viscous Boundary Layers 207 12.1.2 Flow Separation 208 12.1.3 Two-Dimensional Stall Characteristics 209 12.1.4 Three-Dimensional Stall Characteristics 211 12.1.5 Stall Control 211 12.1.6 Stall Prediction 213 12.2 Flight Testing Procedures 214 12.2.1 Flight Characteristics 214 12.2.2 Data Acquisition 216 12.3 Data Analysis 217 12.4 Flight Test Example: Cirrus SR20 219 Nomenclature 221 Subscripts 222 Acronyms and Abbreviations 222 References 222 13 Turning Flight 224 13.1 Theory 224 13.2 Flight Testing Procedures 232 13.2.1 Airworthiness Certification 232 13.2.2 Educational Flight Testing 233 13.2.3 Piloting 233 13.2.4 Instrumentation and Data Recording 234 13.3 Flight Test Example: Diamond DA40 235 Nomenclature 236 Subscripts 237 Acronyms and Abbreviations 237 References 237 14 Longitudinal Stability 238 14.1 Static Longitudinal Stability 238 14.1.1 Theory 238 14.1.2 Trim Condition 242 14.1.3 Flight Testing Procedures 244 14.1.4 Flight Test Example: Cirrus SR20 245 14.2 Dynamic Longitudinal Stability 246 14.2.1 Theory 246 14.2.2 Flight Testing Procedures 254 14.2.3 Flight Test Example: Cirrus SR20 255 Nomenclature 257 Subscripts 259 Acronyms and Abbreviations 259 References 259 15 Lateral-Directional Stability 261 15.1 Static Lateral-Directional Stability 261 15.1.1 Theory 261 15.1.2 Directional Stability 264 15.1.3 Lateral Stability 265 15.1.4 Flight Testing Procedures 266 15.1.5 Flight Testing Example: Cirrus SR20 267 15.2 Dynamic Lateral-Directional Stability 269 15.2.1 Theory 269 15.2.2 Flight Testing Procedures 272 15.2.3 Flight Test Example: Cirrus SR20 272 Nomenclature 274 Acronyms and Abbreviations 275 References 275 16 UAV Flight Testing 277 16.1 Overview of Unmanned Aircraft 277 16.2 UAV Design Principles and Features 279 16.2.1 Types of Airframes 280 16.2.2 UAV System Architecture 281 16.2.3 Electric Propulsion 285 16.2.4 Command and Control (C2) Link 286 16.2.5 Autonomy 287 16.3 Flight Regulations 288 16.4 Flight Testing Principles 288 16.4.1 Air Data Instrumentation 289 16.4.2 UAV Flight Test Planning 290 16.4.3 Piloting for UAV Flight Testing 290 16.5 Flight Testing Examples with the Peregrine UAS 291 16.5.1 Overview of the Peregrine UAS 291 16.5.2 Propulsion System Characterization 293 16.5.3 Specific Excess Power: Level Acceleration and Rate of Climb 294 16.5.4 Glide Flight Tests 296 16.6 Flight Testing Examples with the Avanti UAS 299 16.6.1 Overview of the Avanti UAS 299 16.6.2 Coast-Down Testing for the Drag Polar 301 16.6.3 Radio Range Testing 303 16.6.4 Assessment of Autonomous System Performance 305 16.7 Conclusion 305 Nomenclature 307 Acronyms and Abbreviations 307 References 308 Appendix A Standard Atmosphere Tables 310 Appendix B Useful Constants and Unit Conversion Factors 313 Reference 317 Appendix C Stability and Control Derivatives for a Notional GA Aircraft 318 Reference 319 Index 321