Small Unmanned Fixed-Wing Aircraft Design – Andrew J. Keane, András Sóbester, James P. Scanlan – 1st Edition

List of Figures
List of Tables
Foreword
Series Preface
Preface
Acknowledgments

PART I INTRODUCING FIXED-WING UAVS
1 Preliminaries
1.1 Externally Sourced Components
1.2 Manufacturing Methods
1.3 Project DECODE
1.4 The Stages of Design
1.4.1 Concept Design
1.4.2 Preliminary Design
1.4.3 Detail Design
1.4.4 Manufacturing Design
1.4.5 In-service Design and Decommissioning
1.5 Summary
2 Unmanned Air Vehicles
2.1 A Brief Taxonomy of UAVs
2.2 The Morphology of a UAV
2.2.1 Lifting Surfaces
2.2.2 Control Surfaces
2.2.3 Fuselage and Internal Structure
2.2.4 Propulsion Systems
2.2.5 Fuel Tanks
2.2.6 Control Systems
2.2.7 Payloads
2.2.8 Take-off and Landing Gear
2.3 Main Design Drivers

PART II THE AIRCRAFT IN MORE DETAIL
3 Wings
3.1 Simple Wing Theory and Aerodynamic Shape
3.2 Spars
3.3 Covers
3.4 Ribs
3.5 Fuselage Attachments
3.6 Ailerons/Roll Control
3.7 Flaps
3.8 Wing Tips
3.9 Wing-housed Retractable Undercarriage
3.10 Integral Fuel Tanks
4 Fuselages and Tails (Empennage)
4.1 Main Fuselage/Nacelle Structure
4.2 Wing Attachment
4.3 Engine and Motor Mountings
4.4 Avionics Trays
4.5 Payloads – Camera Mountings
4.6 Integral Fuel Tanks
4.7 Assembly Mechanisms and Access Hatches
4.8 Undercarriage Attachment
4.9 Tails (Empennage)
5 Propulsion
5.1 Liquid-Fueled IC Engines
5.1.1 Glow-plug IC Engines
5.1.2 Spark Ignition Gasoline IC Engines
5.1.3 IC Engine Testing
5.2 Rare-earth Brushless Electric Motors
5.3 Propellers
5.4 Engine/Motor Control
5.5 Fuel Systems
5.6 Batteries and Generators
6 Airframe Avionics and Systems
6.1 Primary Control Transmitter and Receivers
6.2 Avionics Power Supplies
6.3 Servos
6.4 Wiring, Buses, and Boards
6.5 Autopilots
6.6 Payload Communications Systems
6.7 Ancillaries
6.8 Resilience and Redundancy
7 Undercarriages
7.1 Wheels
7.2 Suspension
7.3 Steering
7.4 Retractable Systems
PART III DESIGNING UAVS
8 The Process of Design
8.1 Goals and Constraints
8.2 Airworthiness
8.3 Likely Failure Modes
8.3.1 Aerodynamic and Stability Failure
8.3.2 Structural Failure
8.3.3 Engine/Motor Failure
8.3.4 Control System Failure
8.4 Systems Engineering
8.4.1 Work-breakdown Structure
8.4.2 Interface Deinitions
8.4.3 Allocation of Responsibility
8.4.4 Requirements Flowdown
8.4.5 Compliance Testing
8.4.6 Cost and Weight Management
8.4.7 Design “Checklist”
9 Tool Selection
9.1 Geometry/CAD Codes
9.2 Concept Design
9.3 Operational Simulation and Mission Planning
9.4 Aerodynamic and Structural Analysis Codes
9.5 Design and Decision Viewing
9.6 Supporting Databases
10 Concept Design: Initial Constraint Analysis
10.1 The Design Brief
10.1.1 Drawing up a Good Design Brief
10.1.2 Environment and Mission
10.1.3 Constraints
10.2 Airframe Topology
10.2.1 Unmanned versus Manned – Rethinking Topology
10.2.2 Searching the Space of Topologies
10.2.3 Systematic “invention” of UAV Concepts
10.2.4 Managing the Concept Design Process
10.3 Airframe and Powerplant Scaling via Constraint Analysis
10.3.1 The Role of Constraint Analysis
10.3.2 The Impact of Customer Requirements
10.3.3 Concept Constraint Analysis – A Proposed Computational Implementation
10.3.4 The Constraint Space
10.4 A Parametric Constraint Analysis Report
10.4.1 About This Document
10.4.2 Design Brief
10.4.3 Unit Conversions
10.4.4 Basic Geometry and Initial Guesses
10.4.5 Preamble
10.4.6 Preliminary Calculations
10.4.7 Constraints
10.5 The Combined Constraint Diagram and Its Place in the Design Process
11 Spreadsheet-Based Concept Design and Examples
11.1 Concept Design Algorithm
11.2 Range
11.3 Structural Loading Calculations
11.4 Weight and CoG Estimation
11.5 Longitudinal Stability
11.6 Powering and Propeller Sizing
11.7 Resulting Design: Decode-1
11.8 A Bigger Single Engine Design: Decode-2
11.9 A Twin Tractor Design: SPOTTER
12 Preliminary Geometry Design
12.1 Preliminary Airframe Geometry and CAD
12.2 Designing Decode-1 with AirCONICS
13 Preliminary Aerodynamic and Stability Analysis
13.1 Panel Method Solvers – XFoil and XFLR5
13.2 RANS Solvers – Fluent
13.2.1 Meshing, Turbulence Model Choice, and y+
13.3 Example Two-dimensional Airfoil Analysis
13.4 Example Three-dimensional Airfoil Analysis
13.5 3D Models of Simple Wings
13.6 Example Airframe Aerodynamics
13.6.1 Analyzing Decode-1 with XFLR5: Aerodynamics
13.6.2 Analyzing Decode-1 with XFLR5: Control Surfaces
13.6.3 Analyzing Decode-1 with XFLR5: Stability
13.6.4 Flight Simulators
13.6.5 Analyzing Decode-1 with Fluent
14 Preliminary Structural Analysis
14.1 Structural Modeling Using AirCONICS
14.2 Structural Analysis Using Simple Beam Theory
14.3 Finite Element Analysis (FEA)
14.3.1 FEA Model Preparation
14.3.2 FEA Complete Spar and Boom Model
14.3.3 FEA Analysis of 3D Printed and Fiber- or Mylar-clad Foam Parts
14.4 Structural Dynamics and Aeroelasticity
14.4.1 Estimating Wing Divergence, Control Reversal, and Flutter Onset Speeds
14.5 Summary of Preliminary Structural Analysis
15 Weight and Center of Gravity Control
15.1 Weight Control
15.2 Longitudinal Center of Gravity Control
16 Experimental Testing and Validation
16.1 Wind Tunnels Tests
16.1.1 Mounting the Model
16.1.2 Calibrating the Test
16.1.3 Blockage Effects
16.1.4 Typical Results
16.2 Airframe Load Tests
16.2.1 Structural Test Instruments
16.2.2 Structural Mounting and Loading
16.2.3 Static Structural Testing
16.2.4 Dynamic Structural Testing
16.3 Avionics Testing
17 Detail Design: Constructing Explicit Design Geometry
17.1 The Generation of Geometry
17.2 Fuselage
17.3 An Example UAV Assembly
17.3.1 Hand Sketches
17.3.2 Master Sketches
17.4 3D Printed Parts
17.4.1 Decode-1: The Development of a Parametric Geometry for the SLS Nylon Wing Spar/Boom “Scaffold Clamp”
17.4.2 Approach
17.4.3 Inputs
17.4.4 Breakdown of Part
17.4.5 Parametric Capability
17.4.6 More Detailed Model
17.4.7 Manufacture
17.5 Wings 3
17.5.1 Wing Section Proile
17.5.2 Three-dimensional Wing
PART IV MANUFACTURE AND FLIGHT
18 Manufacture
18.1 Externally Sourced Components
18.2 Three-Dimensional Printing
18.2.1 Selective Laser Sintering (SLS)
18.2.2 Fused Deposition Modeling (FDM)
18.2.3 Sealing Components
18.3 Hot-wire Foam Cutting
18.3.1 Fiber and Mylar Foam Cladding
18.4 Laser Cutting
18.5 Wiring Looms
18.6 Assembly Mechanisms
18.6.1 Bayonets and Locking Pins
18.6.2 Clamps
18.6.3 Conventional Bolts and Screws
18.7 Storage and Transport Cases
19 Regulatory Approval and Documentation
19.1 Aviation Authority Requirements
19.2 System Description
19.2.1 Airframe
19.2.2 Performance
19.2.3 Avionics and Ground Control System
19.2.4 Acceptance Flight Data
19.3 Operations Manual
19.3.1 Organization, Team Roles, and Communications
19.3.2 Brief Technical Description
19.3.3 Operating Limits, Conditions, and Control
19.3.4 Operational Area and Flight Plans
19.3.5 Operational and Emergency Procedures
19.3.6 Maintenance Schedule
19.4 Safety Case
19.4.1 Risk Assessment Process
19.4.2 Failure Modes and Effects
19.4.3 Operational Hazards
19.4.4 Accident List
19.4.5 Mitigation List
19.4.6 Accident Sequences and Mitigation
19.5 Flight Planning Manual
20 Test Flights and Maintenance
20.1 Test Flight Planning
20.1.1 Exploration of Flight Envelope
20.1.2 Ranking of Flight Tests by Risk
20.1.3 Instrumentation and Recording of Flight Test Data
20.1.4 Pre-light Inspection and Checklists
20.1.5 Atmospheric Conditions
20.1.6 Incident and Crash Contingency Planning, Post Crash Safety, Recording, and Management of Crash Site
20.2 Test Flight Examples
20.2.1 UAS Performance Flight Test (MANUAL Mode)
20.2.2 UAS CoG Flight Test (MANUAL Mode)
20.2.3 Fuel Consumption Tests
20.2.4 Engine Failure, Idle, and Throttle Change Tests
20.2.5 Autonomous Flight Control
20.2.6 Auto-Takeoff Test
20.2.7 Auto-Landing Test
20.2.8 Operational and Safety Flight Scenarios
20.3 Maintenance
20.3.1 Overall Airframe Maintenance
20.3.2 Time and Flight Expired Items
20.3.3 Batteries
20.3.4 Flight Control Software
20.3.5 Maintenance Record Keeping
21 Lessons Learned
21.1 Things that Have Gone Wrong and Why
PART V APPENDICES, BIBLIOGRAPHY, AND INDEX
A Generic Aircraft Design Flowchart
B Example AirCONICS Code for Decode-1
C Worked (Manned Aircraft) Detail Design Example
C.1 Stage 1: Concept Sketches
C.2 Stage 2: Part Deinition
C.3 Stage 3: “Flying Surfaces”
C.4 Stage 4: Other Items
C.5 Stage 5: Detail Deinition
Bibliography
Index