Theory Design Air Cushion Craft 2009 Part 11 ppt

... various Hovercraft Craft Country Type Cushion Cushion Craft Cushion Flow Q bar length area weight ^(t) pressure rate 4(m) 5 c (m 2 ) /> c (N/m 2 ) Q (mVs) HM.216 UK SES 11. 95 58.29 ... loss. It is important to remember that cushion air thrusters for ACVs, and cushion vent- ing systems in the case of SES, absorb part of the cushion air flow or l...

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

... 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...

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... K Q 0.16 0.20 0.24 Fig. 15.25 /T T and K Q diagrams for marine propellers. [112 ] 524 Propulsion system design Momentum theory Momentum theory as developed in section 15.1 can be used to carry ... system design where C, is the discharge coefficient for the air jet under the skirt segments. At zero speed in still air equation (15.44) reduces to...

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... 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 ... invention to first application (years) Steam boat 41 Hydrofoil craft 35 Submarine 25 Hovercraft 13 Jet aircraft 12 Aircraft 8 hovercraft, focussing on the UK, form...

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... 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 ... After a time, craft model 711 had been chosen to mount a flexible skirt. The take- off ability of the craft was improved significantly due to the enlarged air...

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... 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 ... T bl Units km/h N/m 2 mVs m m m m 30.67 2690 23.65 0.402 0.0389 0.1535 0.1535 42.90 2716 23.55 0.386 0.0399 0.1385 0.1385 51.08 2763 23.38 0.356 0.0517 0 .111 0 .111 Table 4.6 The calcul...

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... 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 ... restoring force reduces quickly. The Sedam series of craft had cushions with a series of jupes. The highly compartmented cushion provided great heave, pitch and roll stabil...

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

... with two air ducts from the air outlet of the fan have been carried out in the towing tank. Part of the outflow may be led directly into the cushion and another part via air ducts, ... 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...

Ngày tải lên: 11/08/2014, 18:20