{"id":2364,"date":"2019-07-13T16:11:00","date_gmt":"2019-07-13T06:11:00","guid":{"rendered":"https:\/\/pm.hovercraft.technology\/w\/?p=2364"},"modified":"2021-03-01T06:24:01","modified_gmt":"2021-02-28T19:24:01","slug":"bag-skirt-trials-2017","status":"publish","type":"post","link":"https:\/\/pm.hovercraft.technology\/w\/2019\/07\/13\/bag-skirt-trials-2017\/","title":{"rendered":"Bag skirt trials 2017"},"content":{"rendered":"\n

I had been interested in trying to fit a bag skirt on the Turbo\/Revtech craft profile for a a long time. Bag skirts provide a completely different kind of ride and are very economical to make.<\/p>\n\n\n\n

Their main drawback in long term operation is the wear at ground contact (true for all skirt systems) leading to sudden catastrophic failure. This lead me to also wonder if a bag skirt could be fitted with a dedicated wear panel similar to the one that we had in our segments. And rather than just being an afterthought, could the wear panel be designed to alter the characteristics of bag skirts?<\/p>\n\n\n\n

Initial investigation showed that the forces in a dual bag skirt could be balanced. So time to try it out.<\/p>\n\n\n\n

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This is the profile diagram of the dual bag. It’s designed as a full flow bag so there’s no pressure differential between the bag and the cushion. The inner face of the bag is straight, as is the inner edge of the wear bag.<\/p>\n\n\n\n

The broken lines represent the forces in the material. The skirt was designed by establishing the force balance and adjusting key parameters to achieve the design shape.<\/p>\n\n\n\n

The ground contact point is inboard of the outer gunwale, simply to bridge the distance to the ground contact line of the standard extended segments, which are even further inboard.<\/p>\n\n\n\n

The wear bag was modeled as being circular, even on the interior face. It wouldn’t be because the air is accelerating to escape and the local static pressure is falling but I simply didn’t know enough about the mechanics at this point to make a better prediction. Hopefully, the difference compared with the actual shape will be small.<\/p>\n\n\n\n

This is a proof of concept design. Would it even work at all?<\/p>\n<\/div><\/div>\n<\/div><\/div>\n\n\n\n

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This is what was actually made. A four segment bag.<\/p>\n<\/div><\/div>\n<\/div><\/div>\n\n\n\n

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