Originally Posted by aerohead
A client has a 55-foot Prevost motorhome.
* 'Chord' = 55' ( 16.764-meters )
* 'Wingspan' = 8.5' ( 2.59-meters )
* 'Aspect ratio' = 0.154
* 'Wing area' = 467.5 square-feet gross ( 43.432-sq-meters ) [ we can ignore the wheel house areas for simplicity ]
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A cubic-foot is 12-inches on a side, with 1728- cubic-inches volume.
A cubic-foot of 60-degree F water weighs 64.2-pounds.
There are 7.707- gallons in a cubic-foot of water.
Each gallon of that same water weighs essentially 8.33-pounds.
A one-inch 'slice' of a cubic foot of water weighs 5.35-pounds.
One square foot contains 144-square-inches.
One square-inch of water, one-inch 'deep' weighs 0.0578-pounds.
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The World War-II, Waco Aircraft Co. CG - 4G 'Hadrian' assault glider, ( featured in 'Saving Private Ryan )' is cloth-covered, reaching up to 150-mph ( 241.4 km/h ) while towed behind the Douglas C-47, 'Skytrain', then glides to it's target landing zone at around 75-mph ( 120.7 km/h ).
The cloth-covered wings have a design wing loading of 8.33-pounds per square-foot.
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A 'cloth'-skinned belly pan, built to the specification of the Hadrian's wing would support 8.33-pounds per square-foot, at normal loading.
8.33-pounds per square-foot requires a live-load of 1.557-inches of standing water, netting 3,894-pounds of water on top of the pan.
If the Hadrian is designed to a 4g safety factor, positive and negative, then specifications would allow a survivable depth of 6.22-inches of standing water on 'top' of the belly's membrane, still short of structural failure, be it the membrane, ribs, stringers, or 'wing spar'; yielding a live-load of 15,577-pounds of standing water without failure.
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I'm not advocating for allowing 'any' water to make its way onto the top of any belly pan, regardless of materials chosen.
The wheel-houses and inner fender wells will be the focus, as this is where splash and spray originate.
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Most homes and apartments I've experienced have 'ceilings'.
And they're typically constructed with paper-sheathed gypsum board ( Sheetrock' if you will ).
And even though their complete and total destruction is just one, leaking roof away, we continue to construct them, while inspecting, and maintaining roof integrity.
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Seems like a stretched-fabric membrane, securely fastened to it's supporting structure, could function reasonably well as a belly pan, as long as its weaknesses are respected in the 'build.'
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