SMALL UNMANNED FIXED-WING AIRCRAFT DESIGN PDF

Preview

Summary

SMALL UNMANNED FIXED-WING AIRCRAFT DESIGN Related titles Aerospace Series Small Unmanned Fixed-wing Aircraft Design: A Practical Keane October 2017 Approach Performance of the Jet Transport Airplane: Analysis Young August 2017 Methods, Flight Operations, and Regulations Differential Game Theory wit...

Description

SMALL UNMANNED FIXED-WING AIRCRAFT DESIGN

Related titles Aerospace Series Small Unmanned Fixed-wing Aircraft Design: A Practical Approach Performance of the Jet Transport Airplane: Analysis Methods, Flight Operations, and Regulations Differential Game Theory with Applications to Missiles and Autonomous Systems Guidance Advanced UAV Aerodynamics, Flight Stability and Control: Novel Concepts, Theory and Applications Introduction to Nonlinear Aeroelasticity Introduction to Aerospace Engineering with a Flight Test Perspective Aircraft Control Allocation Remotely Piloted Aircraft Systems: A Human Systems Integration Perspective Adaptive Aeroservoelastic Control Theory and Practice of Aircraft Performance The Global Airline Industry, Second Edition Modeling the Effect of Damage in Composite Structures: Simpliied Approaches Introduction to Aircraft Aeroelasticity and Loads, 2nd Edition Aircraft Aerodynamic Design: Geometry and Optimization Theoretical and Computational Aerodynamics Aerospace Propulsion Aircraft Flight Dynamics and Control Civil Avionics Systems, 2nd Edition Modelling and Managing Airport Performance Advanced Aircraft Design: Conceptual Design, Analysis and Optimization of Subsonic Civil Airplanes Design and Analysis of Composite Structures: With Applications to Aerospace Structures, 2nd Edition Aircraft Systems Integration of Air-Launched Weapons Design and Development of Aircraft Systems, 2nd Edition Understanding Aerodynamics: Arguing from the Real Physics Aircraft Design: A Systems Engineering Approach Introduction to UAV Systems 4e Theory of Lift: Introductory Computational Aerodynamics with MATLAB and Octave Sense and Avoid in UAS: Research and Applications Morphing Aerospace Vehicles and Structures Gas Turbine Propulsion Systems Basic Helicopter Aerodynamics, 3rd Edition Advanced Control of Aircraft, Spacecraft and Rockets Cooperative Path Planning of Unmanned Aerial Vehicles Principles of Flight for Pilots Air Travel and Health: A Systems Perspective Design and Analysis of Composite Structures: With applications to aerospace Structures Unmanned Aircraft Systems: UAVS Design, Development and Deployment Introduction to Antenna Placement & Installations

Keane

October 2017

Young

August 2017

Faruqi

May 2017

Marques and Da Ronch

April 2017

Dimitriadis Corda

April 2017 March 2017

Durham, Bordignon and Beck Cooke, Rowe, Bennett. Jr. and Joralmon Tewari Kundu, Price and Riordan Belobaba, Odoni and Barnhart Kassapoglou

January 2017 October 2016

Wright and Cooper Sóbester and Forrester Sengupta Lee Durham Moir, Seabridge and Jukes Zografos, Andreatta and Odoni Torenbeek

December 2014 October 2014 September 2014 October 2013 August 2013 August 2013 July 2013 June 2013

Kassapoglou

April 2013

Rigby Moir and Seabridge McLean Sadraey Fahlstrom and Gleason McBain

April 2013 November 2012 November 2012 October 2012 August 2012 August 2012

Angelov Valasek MacIsaac and Langton Seddon and Newman Tewari Tsourdos et al Swatton Seabridge et al Kassapoglou

April 2012 April 2012 July 2011 July 2011 July 2011 November 2010 October 2010 September 2010 September 2010

Austin

April 2010

Macnamara

April 2010

March 2016 November 2015 July 2015 March 2015

Principles of Flight Simulation Aircraft Fuel Systems The Global Airline Industry Computational Modelling and Simulation of Aircraft and the Environment: Volume 1 - Platform Kinematics and Synthetic Environment Handbook of Space Technology Aircraft Performance Theory and Practice for Pilots Aircraft Systems, 3rd Edition Introduction to Aircraft Aeroelasticity And Loads Stability and Control of Aircraft Systems Military Avionics Systems Design and Development of Aircraft Systems Aircraft Loading and Structural Layout Aircraft Display Systems Civil Avionics Systems

Allerton Langton et al Belobaba Diston

October 2009 May 2009 April 2009 April 2009

Ley, Wittmann Hallmann Swatton Moir & Seabridge Wright & Cooper Langton Moir & Seabridge Moir & Seabridge Howe Jukes Moir & Seabridge

April 2009 August 2008 March 2008 December 2007 September 2006 February 2006 June 2004 May 2004 December 2003 December 2002

SMALL UNMANNED FIXED-WING AIRCRAFT DESIGN A Practical Approach

Andrew J. Keane University of Southampton UK

András Sóbester University of Southampton UK

James P. Scanlan University of Southampton UK

This edition irst published 2017 © 2017 John Wiley & Sons Ltd All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/ permissions. The right of Andrew J. Keane, András Sóbester and James P. Scanlan to be identiied as the authors of this work has been asserted in accordance with law. Registered Ofices John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Editorial Ofice The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK For details of our global editorial ofices, customer services, and more information about Wiley products visit us at www.wiley.com. Wiley also publishes its books in a variety of electronic formats and by print-on-demand. Some content that appears in standard print versions of this book may not be available in other formats. Limit of Liability/Disclaimer of Warranty While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and speciically disclaim all warranties, including without limitation any implied warranties of merchantability or itness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of proit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.

Library of Congress Cataloging-in-Publication Data Names: Keane, Andrew J., author. | Sóbester, András, author. | Scanlan, James P., author. Title: Small unmanned ixed-wing aircraft design : a practical approach / Andrew J. Keane, University of Southampton, UK, András Sóbester, University of Southampton, UK, James P. Scanlan, University of Southampton, UK. Description: First edition. | Hoboken, NJ, USA : John Wiley & Sons, Inc., [2017] | Series: Aerospace series | Includes bibliographical references and index. | Identiiers: LCCN 2017024962 (print) | LCCN 2017027876 (ebook) | ISBN 9781119406327 (pdf) | ISBN 9781119406310 (epub) | ISBN 9781119406297 (cloth) Subjects: LCSH: Drone aircraft–Design and construction. | Airplanes–Design and construction. Classiication: LCC TL685.35 (ebook) | LCC TL685.35 .K43 2017 (print) | DDC 629.133/39–dc23 LC record available at https://lccn.loc.gov/2017024962 Cover image: Courtesy of the authors Cover design by Wiley Set in 10/12pt, TimesLTStd by SPi Global, Chennai, India 10 9 8 7 6 5 4 3 2 1

This book is dedicated to the students of the University of Southampton who have designed, built and lown many UAVs over the last decade and who have been great fun to work with.

Contents List of Figures List of Tables Foreword

xvii xxxiii xxxv

Series Preface

xxxvii

Preface

xxxix

Acknowledgments

PART I 1 1.1 1.2 1.3 1.4

1.5 2 2.1 2.2

xli

INTRODUCING FIXED-WING UAVS

Preliminaries Externally Sourced Components Manufacturing Methods Project DECODE 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 Summary

3 4 5 6 6 8 10 11 12 13 13

Unmanned Air Vehicles A Brief Taxonomy of UAVs 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

15 15 19 21 22 23 24

Contents

x

2.3

2.2.5 Fuel Tanks 2.2.6 Control Systems 2.2.7 Payloads 2.2.8 Take-off and Landing Gear Main Design Drivers

PART II

24 24 27 27 29

THE AIRCRAFT IN MORE DETAIL

3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10

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

33 33 37 37 38 38 40 41 42 42 44

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9

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)

45 45 47 48 50 51 52 54 55 57

5 5.1

5.2 5.3 5.4 5.5 5.6

Propulsion 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 Rare-earth Brushless Electric Motors Propellers Engine/Motor Control Fuel Systems Batteries and Generators

59 59 62 62 65 66 68 70 70 71

6 6.1 6.2

Airframe Avionics and Systems Primary Control Transmitter and Receivers Avionics Power Supplies

73 73 76

Contents

xi

6.3 6.4 6.5 6.6 6.7 6.8

Servos Wiring, Buses, and Boards Autopilots Payload Communications Systems Ancillaries Resilience and Redundancy

78 82 86 87 88 90

7 7.1 7.2 7.3 7.4

Undercarriages Wheels Suspension Steering Retractable Systems

93 93 95 95 97

PART III DESIGNING UAVS 8 8.1 8.2 8.3

The Process of Design Goals and Constraints Airworthiness 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 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”

101 101 103 104 105 106 107 107 110 110 112 112 112 113 114 117

Tool Selection Geometry/CAD Codes Concept Design Operational Simulation and Mission Planning Aerodynamic and Structural Analysis Codes Design and Decision Viewing Supporting Databases

119 120 123 125 125 125 126

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

127 127 127 128 129

8.4

9 9.1 9.2 9.3 9.4 9.5 9.6

Contents

xii

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

145 146 146 146 147 149 151 151 152 154 162

11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9

165 166 169 169 170 170 171 174 177 182

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

130 130 133 136 144 144 144 145

12 Preliminary Geometry Design 12.1 Preliminary Airframe Geometry and CAD 12.2 Designing Decode-1 with AirCONICS

189 190 192

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

195 196 200 204 208 210 212 214 215 221

Contents

13.6.3 Analyzing Decode-1 with XFLR5: Stability 13.6.4 Flight Simulators 13.6.5 Analyzing Decode-1 with Fluent 14 14.1 14.2 14.3

xiii

223 227 228

Preliminary Structural Analysis Structural Modeling Using AirCONICS Structural Analysis Using Simple Beam Theory 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

237 240 243 245 246 250 255 265

15 Weight and Center of Gravity Control 15.1 Weight Control 15.2 Longitudinal Center of Gravity Control

273 273 279

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

281 282 282 284 284 287 290 290 293 294 296 300

17 17.1 17.2 17.3

303 303 306 309 311 311 313

Detail Design: Constructing Explicit Design Geometry The Generation of Geometry Fuselage 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

266 272

313 314 314 315 316

Contents

xiv

17.4.6 17.4.7 17.5 Wings 17.5.1 17.5.2

More Detailed Model Manufacture Wing Section Proile Three-dimensional Wing

317 318 318 320 323

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

331 331 332 332 335 335 337 339 339 342 342 345 346 346 347

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

349 349 351 352 355 356 358 358 359 359 359 360 360 360 361 362 362 363 364

Contents

xv

19.4.5 Mitigation List 19.4.6 Accident Sequences and Mitigation 19.5 Flight Planning Manual

364 366 368

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

369 369 369 370 370 371 371 371 375 375 377 377 377 378 380 380 381 381 382 382 383 383 384

21 Lessons Learned 21.1 Things that Have Gone Wrong and Why

385 388

PART V

APPENDICES, BIBLIOGRAPHY, AND INDEX

A

Generic Aircraft Design Flowchart

395

B

Example AirCONICS Code for Decode-1

399

C C.1 C.2 C.3 C.4 C.5

Worked (Manned Aircraft) Detail Design Example Stage 1: Concept Sketches Stage 2: Part Deinition Stage 3: “Flying Surfaces” Stage 4: Other Items Stage 5: Detail Deinition

425 425 429 434 435 435

Bibliography

439

Index

441

List of Figures The University of Southampton UAV team with eight of our aircraft, March 2015. See also https://www.youtube.com/c/SotonUAV and https://www.sotonuav.uk/.

4

Figure 1.2

The design spiral.

7

Figure 2.1

The Southampton University SPOTTER aircraft at the 2016 Farnborough International Airshow.

19

University of Southampton SPOTTER UAV with under-slung payload pod.

20

Figure 2.3

Integral fuel tank with trailing edge lap and main spars.

21

Figure 2.4

A typical carbon spar and foam wing with SLS nylon ribs at key locations (note the separate aileron and lap with associated servo linkages).

22

Figure 1.1

Figure 2.2

Figure 2.5

A typical SLS structural component.

23

Figure 2.6

A typical integral fuel tank.

25

Figure 2.7

Typical telemetry data recorded by an autopilot. N...