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mick - n/a
16-Sep-06, 07:50 PM
Hopefully somebody can answear this, is there any diferance in hull desigh when fitting a segmented skirt or a bag skirt

Michel - n/a
17-Sep-06, 04:08 AM
YES

Sean Atterbury - n/a
17-Sep-06, 10:05 AM
Great, that helps us dumies a lot, what is the difference?

Michel - n/a
17-Sep-06, 03:59 PM
OK,

I ' m not a dude in this matter,

mainly, a bag skirt can admit even only one big hole to be inflated by prop, and it' s the bag itself which dispatches pressure.

for a segmented skirt you need a hollow duct ( or bag skirt ) all around , to dispatch air flow by holes, one hole or two by segment.

For bag skirt design, ask Keith Smallwood, and for composite skirt ( segments on bag ), Gifford' s one have proven efficiency.

For using them, it' s like cars, some prefer front wheels drive, other better have rear..... Long winter evening gossip, segmented are better for MY use.

ugglas - n/a
17-Sep-06, 07:08 PM
So will a bag skirt work on a craft designed for a segmented skirt?

And a segmented skirt wont work on a craft designed for a bag skirt?

Is this right?

Ian Brooks - n/a
17-Sep-06, 07:38 PM
Hello



There are numerous skirt designs, too much really to go into on the bulletin board. There are several types of bag skirt alone, depending on how the air is delivered into the cushion - essentially you can flow all the air through the bag, or deliever the air directly into the cushion with separate air to inflate the bag, or combinations. You can choose to have segments under the bag, or not, etc. To go from a segment skirt to a bag will almost certainly involve altering the hull, to a greater or lesser extent.



If you want to change the existing skirt for your craft, then you are into designing a new skirt, which is no trivial task, as I just found out by making a small change to my bag skirt - it took a while to understand how to design the new pattern. I would recommend you either entrust this to an expert, or get a good book on the subject - eg "Theory and design of air cushion craft" by Yun and Bliault.



Cheers

Ian

Michel - n/a
17-Sep-06, 11:10 PM
Last year, my friend Benoit ( the flying Doctor ) and I have tried a bag skirt on our Exocets.

For him , with 40 HP, result was equal with easier construction for skirt.

For me , with 25 HP, it was a pain in the bag, speed was half previous one, and consumption 2,5 times the previous one. This year, I have put back a segmented one with various changes, more speed and less consumption than first segmented one.

A hull built for bag skirt can only be fitted with a bag skirt or eventually with a mixed one.

A hull built for segmented skirt can hardly be fitted with bag skirt with a lot of new settings.

For example, my friend has kept the bag skirt on the Exocet , but has a new down hull rebuilt entirely.

All hollow part with dispatching holes have been removed.

kach22i - n/a
18-Sep-06, 09:47 AM
speed was half previous one......................

All hollow part with dispatching holes have been removed.






My experience is about the same with 35 hp.



I've taken a Scat-2 segmented skirt/finger skirt craft and put a bag-like skirt on it. When I say bag-like perhaps I should say a twisted version of a Sevtec skirt but with twin tails. After three years it's almost working, still messing with the splitter, see page nine of the link below.



http://www.hoverclubofamerica.org/forum/index.php?showtopic= (http://www.hoverclubofamerica.org/forum/index.php?showtopic=412) 412



I've retained the air tunnel, still trying to balance out the uneven swirling patterns of air in there.



So far and at this point it's a failure, a real energy hog, but once I get it working right, I'll feel like a Greek God. http://hovercraft.org.uk/images/icons/smiley_icons/icon_lol.gif

Michel - n/a
18-Sep-06, 04:54 PM
Here are last year bag skirt :25 kt, and 7 liters / hour

index.php?t=getfile&id=417&private=0

And , this year with segmented again: 35 kt , and 3, 5 liters / hour

index.php?t=getfile&id=418&private=0

the Exocet was designed for a segmented skirt, and it works well with it.

kach22i - n/a
18-Sep-06, 07:24 PM
Speedymartin, can the "Airbag" craft make it up the rapids with the bag skirt?



Do you have any more pictures of the bikini model? http://hovercraft.org.uk/images/icons/smiley_icons/icon_cool.gif

Michel - n/a
19-Sep-06, 05:38 AM
Hi George,

Yes and yes,

I' ve climbed that weir with bag skirt too, I must recognize that when descending it, with bag skirt , I had a lot less water coming in than with segmented, the craft bounced over waves, and with segmented, it tends to dive under. That was the only positive point for bag skirt last year.

And yes, I have a lot of pictures of the bikini model ( and monokini, and zerokini ), but as it' s offtopic, you have to request them on my e- mail:

speedymartin@libertysurf.fr

index.php?t=getfile&id=419&private=0

Maybe I' ll put a low resolution vid of her driving the craft nude on my You tube gallery....