[PSUBS-MAILIST] Gamma needs a diet
Sean T. Stevenson via Personal_Submersibles
personal_submersibles at psubs.org
Sat May 17 19:31:41 EDT 2014
You mix the foam to a designed density. Deeper foams must be denser, and hence of greater overall volume than a shallower foam for the same buoyancy. Determine your operating depth, determine the largest / lightest spheres you can get away with at that pressure, incorporate some smaller ones to fill the interstitial spaces, mix to maximum volume fraction of glass.
Sean
On May 17, 2014 5:17:12 PM MDT, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>Jim,
>What kind of numbers are we talking here. How much volume of foam per
>lb of buoyancy.
>Hank
>--------------------------------------------
>On Sat, 5/17/14, via Personal_Submersibles
><personal_submersibles at psubs.org> wrote:
>
> Subject: Re: [PSUBS-MAILIST] Gamma needs a diet
> To: personal_submersibles at psubs.org
> Received: Saturday, May 17, 2014, 7:11 PM
>
>
>
>
>
>
> Hank,
> Greatest net buoyancy on your syntactic foam is
> achieved by mixing larger
> spheres with smaller spheres so the smaller ones fit in the
> gaps between the
> larger ones.
> Jim
>
>
> In a message dated 5/17/2014 6:04:36 P.M. Central
> Daylight Time,
> personal_submersibles at psubs.org writes:
> Sean,
> Very interesting, I just googled glass microspheres and
> this is very
> doable.
> Hank
> --------------------------------------------
> On Sat,
> 5/17/14, Sean T. Stevenson via Personal_Submersibles
> <personal_submersibles at psubs.org> wrote:
>
> Subject: Re:
> [PSUBS-MAILIST] Gamma needs a diet
> To: "Personal Submersibles General
> Discussion" <personal_submersibles at psubs.org>
> Received: Saturday, May
> 17, 2014, 6:34 PM
>
> Hollow
> glass microspheres in a (typically) epoxy
> matrix. The
> spheres are so small, they're more like a powder (for a
> deep
> / dense foam. Shallower foams will incorporate larger
> spheres). Mix the
> composite with the highest possible volume
> fraction of glass to
> resin.
> Sean
>
>
>
>
> On May 17, 2014
> 4:09:46 PM MDT, hank
> pronk via Personal_Submersibles
> <personal_submersibles at psubs.org>
> wrote:
> How is syntactic foam made.
> I once experimented with
> 3/4inch plastic water line (pex
> pipe), the stuff we plumb houses with now.
> I heated the end
> of a piece and it melted shut nicely. So I planned
> to make
> a bunch of pipes with both ends melted shut then slide a
> bundle
> of them inside a pvc pipe. Then fill the void with
> poly urethane
> molding resin. It would be cheap and pretty
> tough. Perhaps an
> experiment is in order, unless there is a
> better idea out
> there.
> Hank
>
> On Fri,
> 5/16/14, Sean T. Stevenson via
> Personal_Submersibles
> <personal_submersibles at psubs.org>
> wrote:
>
>
> Subject: Re: [PSUBS-MAILIST] Gamma needs a diet
>
> To:
> "Personal Submersibles General
> Discussion"
> <personal_submersibles at psubs.org>
>
> Received:
> Friday, May 16, 2014, 7:12 PM
>
>
> There's
> always the not-so-easy but
> very elegant solution
> of
> syntactic
> foam filled hydrodynamic fairings.Â
> Go
> bigger than you
> need to
>
> accommodate future expansion,
> and compensate in the
> meantime
> with keel
> weight.Â
> Would improve
> stability, too.
>
> Sean
>
>
>
> On
> 2014-05-15 18:51, hank pronk via
> Personal_Submersibles
>
> wrote:
> Alan,
> That would work
> but
> I want to keep the sub clean on the
>
> outside. Gamma is
> very slippery the way it is. I
> am confident I can shed the
> weight. I have been
>
> weighing all the bits and it looks
> doable. I am also
> looking at a winter project for
> Gamma. I would like
> to
> have the arm, and valve and a
> couple of
> positioningÂ
> thrusters on a common chassis,
> like
> the DW's. I could
> reduce the weight of the
> lead
> drop weight because the entire
> assembly would be
> the drop
> weight. That also solves
> the weight
> problem from the
> batteries. I would use the
>
> original drop weight screw to
> drop the new assembly.
> Hank
>
> On Thu,
> 5/15/14, Alan
> James via Personal_Submersibles
>
> <personal_submersibles at psubs.org>
> wrote:
>
> Â
> Subject: Re:
> [PSUBS-MAILIST] Gamma needs a diet
> Â To:
> "Personal
> Submersibles General Discussion"
>
> <personal_submersibles at psubs.org>
> Â Received: Thursday, May
> 15,
> 2014, 8:17 PM
> Â
> Â Hank,a
> Â
> simple
> solution would be to just have a
> Â number of floats
> like
> Alec's Snoopy.He
> Â has them in a tube, but
> if the floats
> had
> attachment ho!
> les
> Â you
> couldtether
> Â
> them & clip them on or off.Alan
> Â
>
> Â
> Â Â Â
> Â Â Â From: hank
> pronk via
> Â
> Personal_Submersibles
> Â
> <personal_submersibles at psubs.org>
> Â Â Â To:
> Â
> personal_submersibles at psubs.org
>
>
> Â Â Â Sent: Friday,
> Â May 16, 2014 12:04
> PM
> Â Â Â Subject:
> Â [PSUBS-MAILIST] Gamma needs a
> diet
> Â
> Â Â Â
> Â Gamma or the pilot needs
> to go to
> Jenny
> Craig. My new
> Â
> AGM batteries
> weigh 73 lbs each and Gamma has a
> 60 to 65 lb
> Â
> weight
> budget, per battery. That means Gamma
> needs to
> shed
> Â
> some lbs before I can take a passenger. I
>
> can switch
> Â
> to aluminum scuba tanks, not sure the
> weight
> saving
> Â
> there. I can make an aluminum
> rudder and a
> few other
> Â
> parts also.
> Â
> Hank
>
> Â
> Personal_Submersibles mailing
> list
> Â
> Personal_Submersibles at psubs.org
> Â!
>
>
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
> Â
>
> Â
> Â Â Â
> Â
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