[Rhodes22-list] Gas vs Liquid Battens

[Ronald Lipton]

I hadn't thought about CO2 cylinders - that would certainly make it
easier to achieve reasonable pressures and gas would give you the ability
to shape larger areas.  Liquid battens would be limited to local stiffening
by weight considerations. It also depends on the stiffness necessary for the
sail and the wind pressures - but I would guess that a single CO2 cylinder
would be fine for moderate pressurized areas.  A 12 gram cylinder will
provide 150 in^3 at 10 psi.

This can't be too much more complex than swing battens or verical battens.

merry Christmas,

Ron
(I am at work today with not much happening - plenty of time for idle
speculation.)


----- Original Message -----
From: "Roger Pihlaja" <cen09402@centurytel.net>
To: "The Rhodes 22 mail list" <rhodes22-list@rhodes22.org>
Sent: Wednesday, December 25, 2002 4:13 AM
Subject: [Rhodes22-list] Gas vs Liquid Battens


> 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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