[Rhodes22-list] Gas vs Liquid Battens

[Roger Pihlaja]

Ron,

I wouldn't use a compressor to maintain pressure in the gas bladder.  I
would use a disposable cylinder of some cheap inert gas like carbon dioxide
and a pressure regulator to adjust the pressure.  I would think gas bladders
& the necessary gas distribution channels could be built into the new mylar
composite sail fabrics relatively easily using various heat sealing
techniques.  Heck, you could even have a separate channel & regulator for
each bladder so the relative stiffness could be varied over the sail.  The
gas bladder itself could have the appropriate shape designed into it and
would only assume that shape when inflated.  The sail could have a perfect
airfoil shape without any wind in it.  It would also be possible to have
more exotic airfoils with more than just the thickness of sailcloth, more
akin to airplane wings.  We're not talking about real high gas pressures
here, I would think less than 10 psi.  Just remember that liquid water
weighs about 1 g/cc whereas water vapor weighs about 0.07 g/cc.  I would
think liquid bladders would give you a very heavy sail.

Roger Pihlaja
S/V Dynamic Equilibrium

----- Original Message -----
From: "Ronald Lipton" <lipton@sprynet.com>
To: "The Rhodes 22 mail list" <rhodes22-list@rhodes22.org>
Sent: Tuesday, December 24, 2002 4:19 PM
Subject: Re: [Rhodes22-list] Liquid Battens


> An air bladder would be hard to keep sufficiently
> rigid without a fairly high pressure pump and I
> would guess would be harder to engineer into a sail.
> Liquid tubing could be much smaller diameter.
> One could put a liquid system into pockets without
> extensive recutting of standard sails.
> The devil would be in the details - how do you keep
> air bubbles out, how do you fill and empty the system,
> what material do you use for the tubing and how is
> it valved?
>
> The real advantage of the system would be that it would
> give "fill the sails" a whole new meaning.
>
> Ron
>
> ----- Original Message -----
> From: <R22RumRunner@aol.com>
> To: <rhodes22-list@rhodes22.org>
> Sent: Tuesday, December 24, 2002 2:23 PM
> Subject: Re: [Rhodes22-list] Liquid Battens
>
>
> > Ron,
> > I think water would add weight where you don't want it, but an air
bladder
> > arrangement might work as well.
> >
> > Rummy
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