Theory and Design of Air Cushion Craft

647 Pages·2000·45.783 MB·English

by  Liang Yun, Alan Bliault

Theory and Design of Air Cushion Craft
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Theory and Design
of Air Cushion Craft
Liang Yun
Deputy Chief Naval Architect of the Marine
Design & Research Institute of China
Alan Bliault
Shell International Exploration and Production
Ho/Ian
A member of the Hodder Headline Group
LONDON
Copublished in North, Central and South America by
John Wiley & Sons Inc., New York • Toronto
First published in Great Britain in 2000 by
Arnold, a member of the Hodder Headline Group,
338 Huston Road, London NW1 3BH
http://www.arnoldpublishers.com
Copublished in North, Central and South America by
John Wiley & Sons Inc., 605 Third Avenue,
New York, NY 10158-0012
© 2000 L. Yun and A. Bliault
All rights reserved. No part of this publication may be reproduced
or transmitted in any form or by any means, electronically or mechanically,
including photocopying, recording or any information storage or retrieval
system, without either prior permission in writing from the publisher or a
licence permitting restricted copying. In the United Kingdom such licences
are issued by the Copyright Licensing Agency: 90 Tottenham Court Road,
London W1P9HE.
Whilst the advice and information in this book are believed to be true and
accurate at the date of going to press, neither the authors nor the publisher
can accept any legal responsibility or liability for any errors or omissions
that may be made.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
Library of Congress Cataloging-in-Publication Data
A catalog record for this book is available from the Library of Congress
ISBN 0 340 67650 7
ISBN 0 470 23621 3 (Wiley)
123456789 10
Typeset in 10/12 pt Times by J&L Composition Ltd, Filey, North Yorkshire
Printed and bound in Great Britain by Redwood Books Ltd
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This book is dedicated to advancement of Air Cushion Technology, and to the special
band of researchers and engineers worldwide who have created its foundation.
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Contents
Preface xi
Acknowledgements xiii
1. Introduction to hovercraft 1
1.1 Hovercraft beginnings 1
1.2 ACV and SES development in the UK 9
1.3 ACV and SES development in the former USSR 22
1.4 US hovercraft development 25
1.5 ACV and SES development in China 32
1.6 SES and ACV developments in the 1990s 39
1.7 Applications for ACV/SES 41
1.8 The future 45
1.9 SES and ACV design 46
2. Air cushion theory 48
2.1 Introduction 48
2.2 Early air cushion theory developments 50
2.3 Practical formulae for predicting air cushion performance 55
2.4 Static air cushion characteristics on a water surface 66
2.5 Flow rate coefficient method 71
2.6 The 'wave pumping' concept 73
2.7 Calculation of cushion stability derivatives and damping
coefficients 76
3. Steady drag forces 84
3.1 Introduction 84
3.2 Classification of drag components 84
3.3 Air cushion wave-making drag (/? ) 86
w
3.4 Aerodynamic profile drag 96
3.5 Aerodynamic momentum drag 96
3.6 Differential air momentum drag from leakage under bow/stern
seals 97
3.7 Skirt drag 98
viii Contents
3.8 Sidewall water friction drag 104
3.9 Sidewall wave-making drag 111
3.10 Hydrodynamic momentum drag due to engine cooling water 115
3.11 Underwater appendage drag 115
3.12 Total ACV and SES drag over water 117
3.13 ACV skirt/terrain interaction drag 121
3.14 Problems concerning ACV/SES take-off 124
3.15 Effect of various factors on drag 130
4. Stability 136
4.1 Introduction 136
4.2 Static transverse stability of SES on cushion 137
4.3 SES transverse dynamic stability 152
4.4 Calculation of ACV transverse stability 163
4.5 Factors affecting ACV transverse stability 168
4.6 Dynamic stability, plough-in and overturning of hovercraft 173
4.7 Overturning in waves 185
5. Trim and water surface deformation under the cushion 187
5.1 Introduction 187
5.2 Water surface deformation in/beyond ACV air cushion over
calm water 190
5.3 Water surface deformation in/beyond SES air cushion on
calm water 197
5.4 Dynamic trim of ACV/SES on cushion over calm water 200
6. Manoeuvrability 205
6.1 Key ACV and SES manoeuvrability factors 205
6.2 Introduction to ACV control surfaces 207
6.3 Differential equations of motion for ACV manoeuvrability 217
6.4 Course stability 224
6.5 ACV turning performance 227
7. Design and analysis of ACV and SES skirts 232
7.1 Introduction 232
7.2 Development and state of the art skirt configuration 235
7.3 Static geometry and analysis of forces acting on skirts 250
7.4 Geometry and analysis of forces in double or triple bag stern
skirts 258
7.5 Geometry and forces for other ACV skirts 260
7.6 Analysis of forces causing the tuck-under of skirts 261
7.7 Skirt bounce analysis 267
7.8 Spray suppression skirts 270
7.9 Skirt dynamic response 271
8. Motions in waves 273
8.1 Introduction 273
Contents ix
8.2 Transverse motions of SES in beam seas (coupled roll and heave) 279
8.3 Longitudinal SES motions in waves 294
8.4 Longitudinal motions of an ACV in regular waves 308
8.5 Motion of ACV and SES in short-crested waves 322
8.6 Plough-in of SES in following waves 324
8.7 Factors affecting the seaworthiness of ACV/SES 328
9. Model experiments and scaling laws 342
9.1 Introduction 342
9.2 Scaling criteria for hovercraft models during static hovering tests 343
9.3 Scaling criteria for tests of hovercraft over water 348
9.4 Summary scaling criteria for hovercraft research, design and tests 352
10. Design methodology and performance estimation 353
10.1 Design methodology 353
10.2 Stability requirements and standards 355
10.3 Requirements for damaged stability 363
10.4 Requirements for seaworthiness 364
10.5 Requirements for habitability 365
10.6 Requirements for manoeuvrability 374
10.7 Obstacle clearance capability 376
11. Determination of principal dimensions of ACV/SES 377
11.1 The design process 377
11.2 Role parameters 378
11.3 Initial weight estimate 379
11.4 First approximation of ACV displacement (all-up weight),
and estimation of weight in various groups 384
11.5 Parameter checks for ACV/SES during design 397
11.6 Determination of hovercraft principal dimensions 399
12. Lift system design 405
12.1 Introduction 405
12.2 Determination of air flow rate, pressure and lift system power 407
12.3 Design of fan air inlet/outlet systems 413
12.4 Lift fan selection and design 420
13. Skirt design 433
13.1 Introduction 433
13.2 Skirt damage patterns 433
13.3 Skirt failure modes 435
13.4 Skirt loading 437
13.5 Contact forces 441
13.6 Selection of skirt material 442
13.7 Selection of skirt joints 447
13.8 Assembly and manufacturing technology for skirts 449
13.9 Skirt configuration design 451