Theory Design Air Cushion Craft 2009 Part 15 potx

... well- designed installations. Now rjj = (T- Z>j) VJE (from 15. 91) = m[V- } -(\-w)V c - C Di 0.5 IVR V c (1 - vv)] VJE (15. 98) so by following the steps from (15. 93) to (15. 96), ... N/S 2 ( kw cm 2 ) Fig. 15. 44 A/ ss boundaries on plot of water jet thrust vs craft speed. 562 Propulsion system design «ss = n e° 5 /(g X NPSH) 075 (15. 114) =...

Ngày tải lên: 11/08/2014, 18:20

... tank. Part of the outflow may be led directly into the cushion and another part via air ducts, the bow/stern bag and through into the air cushion. The distribution of air flow ... of air leakage and compressibility of cush- ion air will affect the change of cushion pressure and flow rate. Figure 8.42 shows such dependency between the craft dra...

Ngày tải lên: 11/08/2014, 18:20

... of cushion air compression is too small to change the air flow rate and fluctuate the cushion pressure. This is not true for full-scale craft, especially for larger hovercraft ... the craft, W i the weight of various subsystems, L c , B c , H the cushion length, beam and height of the craft and N e , R, p c the engine power, range of the c...

Ngày tải lên: 11/08/2014, 18:20

... structural design 474 14.7 Hovercraft vibration 476 15. Propulsion system design 15. 1 Introduction 15. 2 Air propellers 15. 3 Ducted propellers and fans 15. 4 Marine propellers 15. 5 Water ... 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 predi...

Ngày tải lên: 11/08/2014, 18:20

... shape of cushion plan. For a rectangular air cushion, p s = 1 and will be the minimum, meanwhile C w will be minimum when the cushion plan is rectangular; therefore an air cushion ... craft and C w the wave-making drag coefficient. From this equation we can see that for constant cushion length / c , cushion beam B c and craft weight W, the n...

Ngày tải lên: 11/08/2014, 18:20

... achieve the designer's requirements in the speed range to 40 knots. Above this speed, an air cushion supporting most of the craft weight is most likely to give the optimum design ... post-hump speeds, because a large air flow rate will increase the air component of the two-phase flow blown from the air cushion, producing air lubrication effects...

Ngày tải lên: 11/08/2014, 18:20

... type 717 Item Symbols Dimensions 717 717A 717C Craft weight Cushion length Cushion beam Cushion lib ratio Cushion pressure length ratio Cushion pressure Flow coefficient VCG Bow and ... width W 4 fi c lJB e PA PC Q KG Z b,s a ft 5, t m m kgf/m N/m 2 m m deg deg m 13.7 13.2 3.5 3.77 19.93 2630 0.00757 1.27 0 .15 60 89 0.12 15. 95 15. 2 3.5 4.34 17.31 2630 0.00658 1.27 0 ....

Ngày tải lên: 11/08/2014, 18:20

... deformation in SES air cushion 197 Fig. 5.8 Wave amplitude due to an ACV on shallow water in/off air cushion. 5.3 Water surface deformation in/beyond SES air cushion on calm ... to air cushion and skirt F c = jetted thrust due to air leakage from cushion during turning manoeuvre F m = air momentum force z m = distance from ground to the cent...

Ngày tải lên: 11/08/2014, 18:20

... the cushion pres- sure acting on the stern skirt is uniformly distributed, may not be accurate, particu- larly in the case where craft are running on a water surface. Cushion air ... track of an amphibious hovercraft model landing craft LCAC weigh- ing 150 t, at an initial craft speed of 45 knots. Owing to its rotatable ducted air propellers, the ACV...

Ngày tải lên: 11/08/2014, 18:20

... when the craft is running in high seas and the vertical motion of the craft is very large. In such a case, we can consider air leakage gap, air cushion pressure and air flow rate ... along the longitudinal craft axis. Particularly when the craft is running in high seas, wave perturbations on the craft are severe and this causes local air le...

Ngày tải lên: 11/08/2014, 18:20