Airplane Performance on Grass Airfields

Airplane Performance on Grass Airfields presents an experiment-based approach to analysis and flight testing of airfield performance on grass runways. It discusses improvements for operational efficiency and safety of these airfields. The book analyzes the interaction between the landing gear wheels and the surface of a grass runways during both takeoff and landing. Considering the ground performance of an aircraft on a grass runway, the book covers test methods and devices for measuring performance and introduces an information system for the surface condition of grass airfields: GARFIELD. The system is based on a tire–grass interaction model and uses digital soil maps, as well as current meteorological data obtained from a weather server. The book is intended for researchers and practicing engineers in the fields of aviation and aircraft safety and performance. Cover 1 Half Title 2 Title 4 Copyright 5 Contents 6 Preface 10 Acknowledgments 12 Author biography 14 1 Introduction 16 1.1 Flying on grass airfields 16 1.2 Grass airfields around the world 17 1.3 Flying from grass airfields – major problems 18 1.4 Purpose and scope of the present work 18 1.5 Summary 19 References 19 2 Airfield performance of an airplane – the state-of the-art 22 2.1 Takeoff and landing 22 2.1.1 Takeoff and landing distance measurement 24 2.1.2 Takeoff and landing measurement with the use of GPS and IMU 25 2.1.3 Liftoff 26 2.1.4 Airplane stability during takeoff and landing ground roll 26 2.1.5 Touchdown 29 2.2 Factors having an effect on airfield performance 30 2.2.1 Effects of airplane design 30 2.2.1.1 Powerplant 31 2.2.1.2 Wing 31 2.2.1.3 Landing gear 32 2.2.2 A brief review of airplanes 32 2.2.2.1 The Wilga DRACO 33 2.2.2.2 The Scrappy airplane 35 2.2.3 Airplane certification tests for unpaved runway operation: the Pilatus PC-24 37 2.3 Effect of airfield conditions 41 2.3.1 Definitions 41 2.3.2 Tire–runway interaction 42 2.3.2.1 Tire–runway friction coefficient 42 2.3.2.2 Methods for tire–runway friction measurements 42 2.3.2.3 Rolling resistance coefficient 44 2.3.2.4 Methods for rolling resistance measurement 47 2.3.3 Effect of wind 48 2.3.4 Effect of density altitude 48 2.4 Conclusion 49 References 50 3 Modeling of airfield performance of airplane on a grass runway 52 3.1 Introduction 52 3.2 Wheel–soil interaction modeling 53 3.3 Effect of soil deformation rate 54 3.4 Effect of vegetation 56 3.5 Effect of soil moisture 59 3.6 Synthesis of the model 60 3.6.1 Influence of the soil substrate of the grass runway 60 3.6.2 Determination of tractive forces 60 3.6.3 Modeling the influence of significant factors 61 3.6.3.1 Soil moisture content 61 3.6.3.2 Vegetation 61 3.6.3.3 Wind and density altitude 61 3.7 Concluding remarks 62 References 63 4 Methods 66 4.1 Grass runway surface characterization methods 66 4.1.1 Cone penetrometer – a classic terramechanical instrument 66 4.1.2 TDR – a handheld instrument for soil moisture measurements 68 4.1.3 Method for characterizing the biomass on the grass runway 68 4.2 Airplane performance measurement methods – ground testing 70 4.2.1 Wheel dynamometer for measurements of forces and moments acting on landing gear wheel 70 4.2.1.1 Introduction 70 4.2.1.2 Design and development of the wheel dynamometer system 72 4.2.1.3 Calibration of the sensor 75 4.2.1.4 Data acquisition and online transfer system 79 4.2.1.5 Certification of the sensor for ground and flight testing 79 4.2.2 Methods for determining the rolling resistance and braking friction 81 4.2.2.1 Tire–runway tester for the measurement of rolling resistance and braking friction 81 4.2.2.2 Pull test method 84 4.2.2.3 Instrumented vehicle method 87 4.3 Airplane performance measurement methods – flight testing 89 4.3.1 Flight test method for the determination of rolling resistance 89 4.3.2 Flight test method for the determination of ground reaction under landing gear wheel loading 92 4.3.3 Ground observer method for takeoff and landing ground distance measurement 95 4.3.4 Video camera method 96 4.3.5 Takeoff and landing measurements with the use of AI sensor 96 4.3.5.1 Introduction 96 4.3.5.2 Flight phases’ recognition by means of neural network 97 4.3.5.3 Neural network development 98 4.3.5.4 Instrumentation 99 4.3.5.5 Calibration of the method 101 4.3.5.6 Conclusion 105 4.3.6 Method for airplane stability during takeoff and landing ground roll 105 4.3.6.1 The test airplane and the method 105 4.3.6.2 Flight tests’ campaign 106 4.4 Conclusion 106 References 107 5 Results 110 5.1 Grass runway characterization 110 5.1.1 Cone Index 112 5.1.2 Rolling resistance of grass runway 114 5.1.3 Effect of soil moisture content upon rolling resistance and braking friction 116 5.2 Effect of speed on rolling resistance coefficient 117 5.3 Ground reaction determination under loading of airplane’s wheel at touchdown 119 5.3.1 Soil stress state under the airplane wheel on touchdown 119 5.3.2 Orientation of the inertial force and σ1 122 5.3.3 Concluding remarks 123 5.4 Results from flight test measurements 123 5.4.1 Effect of soil strength 125 5.4.2 Effect of soil moisture 126 5.4.3 Effect of vegetation 127 5.4.4 Effect of wind and density altitude 129 5.4.5 Conclusions 131 5.5 Airplane stability during takeoff ground roll 131 5.5.1 Effect of short grass 132 5.5.2 Effect of tall grass 134 5.5.3 Conclusion 134 5.6 Summary 134 References 137 6 GARFIELD – an online information system on grassy airfields 140 6.1 Introduction 140 6.2 Motivation 141 6.3 GARFIELD system description 143 6.4 Methodology 144 6.4.1 Wheel–grass interaction modeling 144 6.4.2 GARFIELD software development 145 6.4.3 System validation 145 6.5 GRASSTAM – a notice on grass runway surface condition 145 6.5.1 Introduction 145 6.5.2 An idea of the GRASSTAM 146 6.5.3 Method of grass runway assessment 146 6.6 Conclusion 149 References 149 Index 152 Terramechanics;,AI;,Instrumentation;,Sensors;,Takeoff;,Flight,testing;,Wheel-soil,interaction;,Airplane,ground,performance Terramechanics,AI,Instrumentation,Sensors,Takeoff,Flight testing,Wheel-soil interaction,Airplane ground performance "Airplane Performance on Grass Airfields presents an experiment-based approach to analysis and flight testing of airfield performance on grass runways. It discusses improvements for operations efficiency and safety of these airfields. The book is intended for researchers and practicing engineers in the fields of aviation and aircraft safety and performance. The book analyzes the interaction between the landing gear wheels and the surface of a grass runways during both takeoff and landing. It covers test methods and devices for measuring performance and introduces an information system for the surface condition of grass airfields: GARFIELD"-- Provided by publisher