From: vbra676539@aol.com
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Thought experiment
Date: Thu, 19 Jul 2007 19:05:01 -0400
Joe, What about control surfaces? Like a glider, it seems that some kind of
wing would be necessary, and if you've got one of those, then you might as
well be able to tilt it for control. And the same for a rudder.?Fine
buoyancy control is all well and good for hovering in a?powered
boat,?although mostly unnecessary, I've found. However, the gravity powered
sub is going to need a little guidance to extend the glide path, control
heading changes and avoid the occasional pod of humming whales, yes??You've
done away with thrusters for primary motive force, but in fact, you'll
still have moving water to contend with. It looks to me that control
surfaces would be even more important in this application. As for?dropping
shot, I want?you to have a quick look at your bathtub and think about
loading that much rusty buckshot into your tanks for every dive. Yoikes!!!
I'd say external hard tanks mounted fore and aft and overboard pumps or
compensated HP air (much faster trim changes)?mi!
ght be better in the long run. And cheaper. Flood the tanks and the boat
gains weight?without changing displacement and down you go. Use a moveable
weight for pitch change, flood heavy, and OFF you go!!!?Better pack a
lunch, though. It's going to take a while.?Vance?
-----Original Message-----
From: Joseph Perkel <joeperkel@hotmail.com>
To: personal_submersibles@psubs.org
Sent: Thu, 19 Jul 2007 5:08 pm
Subject: RE: [PSUBS-MAILIST] Thought experiment
Phillip,
Sorry for the delayed response but, I had to think about the question and,
take a peek at C-BUG again. I find the question itself interesting?because
fine buoyancy control, is of particular interest to me, (although
by?different methods). So this is an exercise in basic buoyancy control for
me as well.
In our application, we have buoyancy and thrust as our?2 ways of changing
depth....correct? For the glider method,...... eliminate thrust.
I'm not quite clear on the "suspending" piston idea but, in thinking about
this "non-powered" mode of changing depth, we're left only with
manipulation of buoyancy...correct?
This had me thinking about , what manner of "ballast control", would?I
personally feel comfortable with in this application and,... like
you,....?I feel air is unattractive for the ascent phase as..."failure is
not an option".
So for my "glider", in the negative buoyancy phase, descent would be
initiated from a positive buoyancy condition on the surface by, standard
venting of soft tanks. The positive buoyancy ascent phase, would be by
releasing lead shot via some type of failsafe release mechanism,
(electromechanical).
Hope to be of some help and, thanks for the mind bender!
Joe
From:??Philip Ridenauer <akula151@yahoo.com>
Reply-To:??personal_submersibles@psubs.org
To:??personal_submersibles@psubs.org
Subject:??[PSUBS-MAILIST] Thought experiment
Date:??Sun, 15 Jul 2007 13:47:00 -0700 (PDT)
??
??
??
??
??
??
??
I've been running a thought experiment in my head for an ambient dry glider
(though I suppose a 1atm sub could do the same).? The idea is to have the
sub ballasted negatively and use gravity as the propulsion source.? At max
depth (depending upon how much pressure the pilot was willing to
risk/withstand)?enough ballast is expelled to provide positive bouyancy.?
The ballast taken on and expelled should be forward of the CG to provide
nose down attitude at neg. bouyancy and nose up at pos.
the sub ballasted negatively and use gravity as the propulsion source.? At
max depth (depending upon how much pressure the pilot was willing to
risk/withstand)?enough ballast is expelled to provide positive bouyancy.?
The ballast taken on and expelled should be forward of the CG to provide
nose down attitude at neg. bouyancy and nose up at pos.
??
Query:? is there a means of expelling ballast water mechanically so that
one does not have to carry an inordinate amount of compressed air to
achieve this effect?
??
I have an idea for a suspended weight acting as a piston but don't know if
this is feasible.
??
Just toying with an idea.
??
PR
??
ps? My computer and server are sloooow, so I don't ck my email every day.?
It might take me a while to reply to any questions.?
?
to reply to any questions.?
?
??
?????? Take the Internet to Go: Yahoo!Go puts the Internet in your pocket:
mail, news, photos & more.
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