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Small Unmanned Fixed-Wing Aircraft Design. A Practical Approach

Preface I Introducing Fixed-Wing UAVs Preliminaries Externally Sourced Components Manufacturing Methods Project DECODE The Stages of Design Concept Design Preliminary Design Detail Design Manufacturing Design In-service Design and Decommissioning Summary Unmanned Air Vehicles A Brief Taxonomy of UAVs The Morphology of a UAV Lifting Surfaces Control Surfaces Fuselage and Internal Structure Propulsion Systems Fuel Tanks Control Systems Payloads Take-off and Landing Gear Main Design Drivers II The Aircraft in More Detail Wings Simple Wing Theory and Aerodynamic Shape Spars Covers Ribs Fuselage Attachments Ailerons/Roll Control Flaps Wing Tips Wing-housed Retractable Undercarriage Integral Fuel Tanks Fuselages and Tails (Empennage)Main Fuselage/Nacelle Structure Wing Attachment Engine and Motor Mountings Avionics Trays Payloads - Camera Mountings Integral Fuel Tanks Assembly Mechanisms and Access Hatches Undercarriage Attachment Tails (Empennage)Propulsion Liquid-Fueled IC Engines Glow-plug IC Engines Spark Ignition Gasoline IC Engines IC Engine Testing Rare-earth Brushless Electric Motors Propellers Engine/Motor Control Fuel Systems Batteries and Generators Airframe Avionics and Systems Primary Control Transmitter and Receivers Avionics Power Supplies Servos Wiring, Buses, and Boards Autopilots Payload Communications Systems Ancillaries Resilience and Redundancy Undercarriages Wheels Suspension Steering Retractable Systems III Designing UAVs The Process of Design Goals and Constraints Airworthiness Likely Failure Modes Aerodynamic and Stability Failure Structural Failure Engine/Motor Failure Control System Failure Primary Tx/Rx Failure Control Surface Failure Autopilot Failure Systems Engineering Work-breakdown Structure Interface Definitions Allocation of Responsibility Requirements Flowdown Compliance Testing Cost and Weight Management Design “Checklist”Tool Selection Geometry/CAD Codes Concept Design Operational Simulation and Mission Planning Aerodynamic and Structural Analysis Codes Design and Decision Viewing Supporting Databases Concept Design: Initial Constraint Analysis The Design Brief Drawing up a Good Design Brief Environment and Mission Constraints Airframe Topology Unmanned versus Manned - Rethinking Topology Searching the Space of Topologies Systematic “invention” of UAV Concepts Division “Taking Out”Adapting the Design to Local Conditions Asymmetry Multiple Functions Nesting Blessing in Disguise Designing for Failure The Other Way Around Periodic Action Rushing Through Cheap/Disposable Components Color Change Discarding (and Recovery?)Managing the Concept Design Process Airframe and Powerplant Scaling via Constraint Analysis The Role of Constraint Analysis The Impact of Customer Requirements Concept Constraint Analysis - A Proposed Computational Implementation The Constraint Space A Parametric Constraint Analysis Report About This Document Design Brief Take-off performance Climb Performance Turn Performance Approach and Landing Unit Conversions Basic Geometry and Initial Guesses Preamble Preliminary Calculations The Operating Environment Basic Aerodynamic Performance Calculations Constraints Constraint 1: Level, Constant Velocity Turn Constraint 2: Rate of Climb Constraint 3: Take-Off Ground Run Constraint Constraint 4: Desired Cruise Airspeed Constraint 5: Approach Speed Combined Constraint Diagram The Combined Constraint Diagram and Its Place in the Design Process Spreadsheet-Based Concept Design and Examples Concept Design Algorithm Range Structural Loading Calculations Weight and CoG Estimation Longitudinal Stability Powering and Propeller Sizing Resulting Design: Decode-1 A Bigger Single Engine Design: Decode-2 A Twin Tractor Design: SPOTTER Preliminary Geometry Design Preliminary Airframe Geometry and CAD Designing Decode-1 with AirCONICS Preliminary Aerodynamic and Stability Analysis Panel Method Solvers - XFoil and XFLR5 RANS Solvers - Fluent Meshing, Turbulence Model Choice, andy+Example Two-dimensional Airfoil Analysis Example Three-dimensional Airfoil Analysis D Models of Simple Wings Example Airframe Aerodynamics Analyzing Decode-1 with XFLR5: Aerodynamics Analyzing Decode-1 with XFLR5: Control Surfaces Analyzing Decode-1 with XFLR5: Stability Flight Simulators Analyzing Decode-1 with Fluent Preliminary Structural Analysis Structural Modeling Using AirCONICS Structural Analysis Using Simple Beam Theory Finite Element Analysis (FEA)FEA Model Preparation FEA Complete Spar and Boom Model FEA Analysis of 3D Printed and Fiber- or Mylar-clad Foam Parts Structural Dynamics and Aeroelasticity Estimating Wing Divergence, Control Reversal, and Flutter Onset Speeds Summary of Preliminary Structural Analysis Weight and Center of Gravity Control Weight Control Longitudinal Center of Gravity Control Experimental Testing and Validation Wind Tunnels Tests Mounting the Model Calibrating the Test Blockage Effects Typical Results Basic Results Elevator Effectiveness Rudder Effectiveness Airframe Load Tests Structural Test Instruments Structural Mounting and Loading Static Structural Testing Dynamic Structural Testing Avionics Testing Detail Design: Constructing Explicit Design Geometry The Generation of Geometry Fuselage An Example UAV Assembly Hand Sketches Master Sketches D Printed Parts Decode-1: The Development of a Parametric Geometry for the SLS Nylon Wing Spar/Boom “Scaffold Clamp”Approach Inputs Breakdown of Part Parametric Capability More Detailed Model Manufacture Wings Wing Section Profile Three-dimensional Wing IV Manufacture and Flight Manufacture Externally Sourced Components Three-Dimensional Printing Selective Laser Sintering (SLS)Fused Deposition Modeling (FDM)Sealing Components Hot-wire Foam Cutting Fiber and Mylar Foam Cladding Laser Cutting Wiring Looms Assembly Mechanisms Bayonets and Locking Pins Clamps Conventional Bolts and Screws Storage and Transport Cases Regulatory Approval and Documentation Aviation Authority Requirements System Description Airframe Performance Avionics and Ground Control System Acceptance Flight Data Operations Manual Organization, Team Roles, and Communications Brief Technical Description Operating Limits, Conditions, and Control Operational Area and Flight Plans Operational and Emergency Procedures Maintenance Schedule Safety Case Risk Assessment Process Failure Modes and Effects Operational Hazards Accident List Mitigation List Accident Sequences and Mitigation Flight Planning Manual Test Flights and Maintenance Test Flight Planning Exploration of Flight Envelope Ranking of Flight Tests by Risk Instrumentation and Recording of Flight Test Data Pre-flight Inspection and Checklists Atmospheric Conditions Incident and Crash Contingency Planning, Post Crash Safety, Recording, and Management of Crash Site Test Flight Examples UAS Performance Flight Test (MANUAL Mode)UAS CoG Flight Test (MANUAL Mode)Fuel Consumption Tests Engine Failure, Idle, and Throttle Change Tests Autonomous Flight Control Auto-Takeoff Test Auto-Landing Test Operational and Safety Flight Scenarios Maintenance Overall Airframe Maintenance Time and Flight Expired Items Engine Servicing Servos and Control Surfaces Batteries Flight Control Software Maintenance Record Keeping Lessons Learned Things that Have Gone Wrong and Why V Bibliography

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