Lighter Than Air Systems : Proceedings of the International Conference on Design and Engineering of Lighter-Than-Air Systems 2022 (DELTAs-2022)

This book presents select peer reviewed proceedings of the International Conference on Design and Engineering of Lighter-Than-Air Systems (DELTAs 2022) which was held at the Department of Aerospace Engineering, Indian Institute of Technology (IIT) Bombay. It highlights current research trends and advancements in the field of lighter-than-air (LTA) systems. The topics covered include design (conventional and unconventional), aerodynamics (CFD), structures, loads and materials, stability and control, operations and ground handling, multidisciplinary design optimization, and novel applications of LTA systems. The book will be a valuable reference for researchers and professionals interested in lighter-than-air systems and allied fields. Conference Committee Reviewers Preface Contents About the Editor Effect of Geometrical Parameters of a Tethered Aerostat on Longitudinal Stability Boundaries 1 Introduction 2 Mathematical Modeling 2.1 Aerodynamic Forces and Moments 2.2 Tether Cable Forces and Moments 2.3 Buoyancy Forces and Moments 2.4 Gravity Forces and Moments 3 Estimation of the Stability Characteristics 3.1 Balloon Equations of Motion 3.2 Equilibrium Trim Conditions 3.3 Formulations for Calculation of Stability Derivatives 3.4 Equilibrium Cable Shape 3.5 Cable Force Derivatives 3.6 Stability Equations (Longitudinal) 4 Effect of Geometrical Parameters on Longitudinal Stability Boundaries 5 Conclusion References CPACS LTA—Using Common Data Structures for Visualization and Optimization of Airship Designs 1 Introduction 1.1 Background 1.2 Objectives 2 Problem Definition and Formulation 3 Methodology 3.1 Airship Modeling 3.2 Parameter Estimation 3.3 Design Optimization 4 Results 5 Discussion and Conclusions References Airship Sling-Load Operations: A Model Flight-Test Approach 1 Introduction 1.1 Background 1.2 Objectives 2 Problem Definition and Formulation 2.1 Load Exchange and Certification 2.2 Maneuverability 3 Methodology 3.1 Sling-Load Operation 3.2 Model Flight-Test 4 Results 4.1 Cruise Mode 4.2 Dynamic Positioning 5 Discussion and Conclusions 5.1 Discussion 5.2 Conclusion References Optimization of TPU/TiO2 Films Using UV Additives for Improved Weather Stability of LTA Hull Materials 1 Introduction 2 Methodology 2.1 Materials 2.2 Method of Preparation of Films 2.3 UV–VIS Spectroscopy 2.4 Fourier Transform Infra-Red Spectroscopy (FTIR) 2.5 Artificial Accelerated Weathering 2.6 UPF Measurement 2.7 Yellowness Index 2.8 Gas Barrier Measurement 2.9 Tensile Testing of Films 3 Results and Discussion 3.1 UV–VIS Spectroscopy 3.2 Fourier Transform Infra-Red Spectroscopy 3.3 UPF Measurement 3.4 Yellowness Index 3.5 Gas Barrier Properties 3.6 Tensile Testing 4 Future Scope 5 Conclusion References Airship Turn Performance Estimated From Efficient Potential Flow Panel Method 1 Introduction 2 Problem Definition and Formulation 3 Methodology 4 Results 5 Discussion and Conclusions References Evaluation of High-Performance Fabric-Based Laminated Hull Material for High-Altitude Airship 1 Introduction 1.1 High-Altitude Airship System 2 Materials and Methods 2.1 Materials 2.2 Methods 3 Characterizations and Testing 3.1 Wide Angle X-ray Diffraction (XRD) 3.2 Differential Scanning Calorimetry (DSC) 3.3 Drop Shape Analyzer (DSA) 3.4 Atomic Force Microscopy (AFM) 3.5 T-Peel Test 3.6 Tensile Test 3.7 Tearing Test 3.8 Helium Gas Permeability Test 3.9 UV Protection Factor (UPF) 4 Results and Discussion 4.1 XRD Study 4.2 DSC Study 4.3 Helium Gas Permeability 4.4 Adhesion Studies 4.5 AFM Analysis 4.6 Effect of Crosslinker on Peel Strength 5 Study on Adhesive-Coated and Laminated Fabrics 5.1 Thickness and Weight of the Laminates 5.2 Effect of UV Additive on Peel Strength 5.3 Effect of UV Additive and Accelerated Weathering on UPF Value 5.4 Effect of Plasma Treatment on Peel Strength 5.5 Effect of Accelerated Weathering on Peel Strength 5.6 Effect of Water Soaking on Peel Strength 5.7 Effect of Accelerated Weathering on Tensile Properties 5.8 Effect of Accelerated Weathering on Tearing Strength 5.9 Effect of Accelerated Weathering on Gas Barrier Property 6 Butt Joint Strength 7 Conclusion References Look Ahead Steering-Based Path Following Control for an Airship 1 Introduction 2 Airship Model 2.1 Linearization of Equations of Motion 3 Automatic Flight Control System 3.1 Guidance and Navigation Algorithm 3.2 Reference Model 3.3 Control System Design 4 Simulation Results 5 Conclusion References Functionalization of Polyurethane-Based Adhesives with UV Additives for LTA Applications 1 Introduction 2 Problem Definition and Formulation 3 Experimental 3.1 Materials 3.2 Methods 4 Characterization and Testing 4.1 ATR-FTIR 4.2 Tensile Testing and Peel Strength Testing 4.3 Helium Gas Permeability 4.4 Ultraviolet Protection Factor (UPF) 4.5 Differential Scanning Calorimetry (DSC) 4.6 Thermogravimetric Analysis (TGA) 5 Results and Discussion 5.1 Fourier Transform Infrared Spectroscopy (FTIR) Analysis 5.2 Peel Strength Test 5.3 Helium Permeability Testing 5.4 UV Protection Factor (UPF) Analysis 5.5 Thermogravimetric Analysis (TGA) 5.6 Differential Scanning Calorimetry (DSC) Analysis 6 Conclusion References Degradation Study of Aromatic and Aliphatic TPU Films in Accelerated Weathering: Impact on the Gas Barrier and Mechanical Properties 1 Introduction 2 Material and Method 2.1 Materials 2.2 TPU Extrusion Cast Film Preparation 2.3 Artificial Accelerated Weathering Test 2.4 Characterization Techniques 3 Results and Discussion 3.1 Mechanical Properties 3.2 Helium Gas Permeability 3.3 Surface Degradation 3.4 Chemical Structure 3.5 UPF Measurement 4 Conclusion References A Multidisciplinary Design Optimisation (MDO) Algorithm for the Automatic Sizing of an Unmanned Lighter-Than-Air Platform 1 Introduction 1.1 Problem Definition and Formulation 2 Methodology 3 Results 3.1 Variation of Payload and Associated Power 3.2 Energy Systems 4 Discussion and Conclusions References The Concepts of Telescopic and Self-Deployable Tensegrity-Based Helium-Filled Aerostats 1 Introduction 2 The Concept of Adaptive Telescopic Aerostats 3 Comparison of Strategies for Control of Aerostat Motion 4 The Concept of Tensegrity-Based Aerostat 5 Strength Analysis of Tensegrity-Based Aerostat 6 Discussion and Conclusions References Numerical Investigation of Laminar to Turbulent Boundary Layer Transition Over Airship Envelopes 1 Introduction 2 Validation for Flat Plate Cases 3 Establishing Efficacy of OpenFOAM® for Bodies of Revolution 3.1 Drag Calculation of GNVR Envelope 3.2 Assumed Transition Point Approach for Zhiyuan–1 Envelope 3.3 Evaluation of Transition Turbulence Model for Zhiyuan-1 Envelope 3.4 Transition Analysis on Zhiyuan-1 Envelope at Angle of Attack 4 Conclusions References Designing Helium-Filled Aerostats Applying Scaling Procedure, Mini-Models CANDY and Fly-Tests on SKYLAB 1 Introduction 2 Testing V-Mobility Via Mini-Models CANDY 3 Volume Measurement by Optical Technique 4 The Scaling Procedure 5 The Case Studies 5.1 Numerical Model 5.2 Numerical Simulation of Aero-SDT Mission 6 Discussion and Conclusions References Effect of Reynolds Number on the Aerodynamic Characteristics of Leading-Edge Protuberanced Airship Fin 1 Introduction 2 Computational Methodology 3 Results and Discussion 3.1 Effect of Re on the Lift Characteristics Curve of LEP Fin 3.2 Effect of Re on the Drag Characteristics Curve of LEP Fin 4 Conclusion References Autonomous Tilt Rotor Stabilized Plimp Hybrid Airship Unmanned Aerial Vehicle 1 Literature Review 2 Introduction 3 Design 3.1 Material Selection 3.2 Stability of Airship 3.3 The Various Forces and the Various Moments Acting on the Plimp 3.4 Plimp Stability from Designer Point of View 3.5 Requirements of the Hybrid VTOL Plimp Airship Unmanned Aerial Vehicle 4 Calculations 4.1 Weight Estimation 4.2 Airfoil Data for the Wing 4.3 Propeller Data 4.4 Different Phases of Flight 5 Mathematical Modeling and Autopilot Control System 6 Results 7 Summary 8 Conclusion References Numerical Approach to Maneuver Design and Feasibility Evaluation for the Autonomy of Airship 1 Introduction 2 6-DoF Aircraft Equations of Motion 2.1 Buoyant and Gravitational Terms 2.2 Aerodynamic and Control Terms 2.3 Propulsive Terms 3 Direct Continuation Methodology for Constrained Dynamical Systems 4 Maneuver Design with Feasibility Evaluation 4.1 Straight and Level Flight Maneuver 4.2 Level Turn Maneuver 4.3 Ascend and Descend Maneuvers 5 Validation 5.1 Level Performance Analysis 5.2 Ascend Maneuver Evaluation 6 Conclusions References Estimation of Stability Derivatives Due to Translational Motion of Various LTA Vehicles Using CFD 1 Introduction 2 Stability Derivatives Extraction Methodology 3 Aerostat Shapes 4 Numerical Simulation 4.1 Governing Equations 4.2 Computational Domain and Grid 5 Results and Discussion 5.1 Grid and Time Step Independence Study 5.2 Validation of the Grid Motion 5.3 Validation of the Stability Derivative Extraction Methodology 5.4 Acceleration and Frequency Independence Study 5.5 Zhiyuan Aerostat 5.6 GNVR, HAA and NPL Aerostats 6 Conclusions and Future Scope References