Theory and Design of Air Cushion Craft

Contents......Page 8
Preface......Page 12
Acknowledgements......Page 14
1.1 Hovercraft beginnings......Page 16
1.2 ACV and SES development in the UK......Page 24
1.3 ACV and SES development in the former USSR......Page 37
1.4 US hovercraft development......Page 40
1.5 ACV and SES development in China......Page 47
1.6 SES and ACV developments in the 1990s......Page 54
1.7 Applications for ACV/SES......Page 56
1.8 The future......Page 60
1.9 SES and ACV design......Page 61
2.1 Introduction......Page 63
2.2 Early air cushion theory developments......Page 65
2.3 Practical formulae for predicting air cushion performance......Page 70
2.4 Static air cushion characteristics on a water surface......Page 81
2.5 Flow rate coefficient method......Page 86
2.6 The 'wave pumping' concept......Page 88
2.7 Calculation of cushion stability derivatives and damping coefficients......Page 91
3.2 Classification of drag components......Page 99
3.3 Air cushion wave-making drag (R[sub(w)])......Page 101
3.5 Aerodynamic momentum drag......Page 111
3.6 Differential air momentum drag from leakage under bow/stern seals......Page 112
3.7 Skirt drag......Page 113
3.8 Sidewall water friction drag......Page 119
3.9 Sidewall wave-making drag......Page 126
3.11 Underwater appendage drag......Page 130
3.12 Total ACV and SES drag over water......Page 132
3.13 ACV skirt/terrain interaction drag......Page 136
3.14 Problems concerning ACV/SES take-off......Page 139
3.15 Effect of various factors on drag......Page 145
4.1 Introduction......Page 151
4.2 Static transverse stability of SES on cushion......Page 152
4.3 SES transverse dynamic stability......Page 167
4.4 Calculation of ACV transverse stability......Page 178
4.5 Factors affecting ACV transverse stability......Page 183
4.6 Dynamic stability, plough-in and overturning of hovercraft......Page 188
4.7 Overturning in waves......Page 200
5.1 Introduction......Page 202
5.2 Water surface deformation in/beyond ACV air cushion over calm water......Page 205
5.3 Water surface deformation in/beyond SES air cushion on calm water......Page 212
5.4 Dynamic trim of ACV/SES on cushion over calm water......Page 215
14.2 External forces on hull – introduction to the strength calculation of craft......Page 0
6.2 Introduction to ACV control surfaces......Page 222
6.4 Course stability......Page 239
6.5 ACV turning performance......Page 242
7.1 Introduction......Page 247
7.2 Development and state of the art skirt configuration......Page 250
7.3 Static geometry and analysis of forces acting on skirts......Page 265
7.4 Geometry and analysis of forces in double or triple bag stern skirts......Page 273
7.5 Geometry and forces for other ACV skirts......Page 275
7.6 Analysis of forces causing the tuck-under of skirts......Page 276
7.7 Skirt bounce analysis......Page 282
7.8 Spray suppression skirts......Page 285
7.9 Skirt dynamic response......Page 286
8.1 Introduction......Page 288
8.2 Transverse motions of SES in beam seas (coupled roll and heave)......Page 294
8.3 Longitudinal SES motions in waves......Page 309
8.4 Longitudinal motions of an ACV in regular waves......Page 323
8.5 Motion of ACV and SES in short-crested waves......Page 337
8.6 Plough-in of SES in following waves......Page 339
8.7 Factors affecting the seaworthiness of ACV/SES......Page 343
9.1 Introduction......Page 357
9.2 Scaling criteria for hovercraft models during static hovering tests......Page 358
9.3 Scaling criteria for tests of hovercraft over water......Page 363
9.4 Summary scaling criteria for hovercraft research, design and tests......Page 367
10.1 Design methodology......Page 368
10.2 Stability requirements and standards......Page 370
10.3 Requirements for damaged stability......Page 378
10.4 Requirements for seaworthiness......Page 379
10.5 Requirements for habitability......Page 380
10.7 Obstacle clearance capability......Page 391
11.1 The design process......Page 392
11.2 Role parameters......Page 393
11.3 Initial weight estimate......Page 394
11.4 First approximation of ACV displacement (all-up weight), and estimation of weight in various groups......Page 399
11.5 Parameter checks for ACV/SES during design......Page 412
11.6 Determination of hovercraft principal dimensions......Page 414
12.1 Introduction......Page 420
12.2 Determination of air flow rate, pressure and lift system power......Page 422
12.3 Design of fan air inlet/outlet systems......Page 428
12.4 Lift fan selection and design......Page 435
13.2 Skirt damage patterns......Page 448
13.3 Skirt failure modes......Page 450
13.4 Skirt loading......Page 452
13.5 Contact forces......Page 456
13.6 Selection of skirt material......Page 457
13.7 Selection of skirt joints......Page 462
13.8 Assembly and manufacturing technology for skirts......Page 464
13.9 Skirt configuration design......Page 466
14.1 ACV and SES structural design features......Page 473
14.3 Brief introduction to the structural calculation used in MARIC......Page 480
14.4 Calculation methods for strength in the former Soviet Union......Page 482
14.5 Safety factors......Page 488
14.6 Considerations for thickness of plates in hull structural design......Page 489
14.7 Hovercraft vibration......Page 491
15.1 Introduction......Page 502
15.2 Air propellers......Page 522
15.3 Ducted propellers and fans......Page 530
15.4 Marine propellers......Page 535
15.5 Water jets......Page 551
15.6 Power transmission......Page 579
15.7 Surface contact propulsion......Page 589
16.1 Introduction......Page 592
16.2 Powering estimation......Page 600
16.3 Diesel engines......Page 603
16.4 Gas turbines......Page 611
16.5 General design requirements......Page 619
16.6 Machinery space layout......Page 621
16.8 Operation and maintenance......Page 622
References......Page 627
A......Page 633
B......Page 634
D......Page 635
E......Page 636
G......Page 637
H......Page 638
M......Page 639
O......Page 640
R......Page 641
S......Page 642
V......Page 645
W......Page 646
Y......Page 647