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Re: [PSUBS-MAILIST] Drag

Hi Rick,
Yes, there is a lot to see close by but, towing a K-sub through inlets is a no no. So where I take it locally, will have to be within range of the Stiltsville channel....see map..... 

http://www.nps.gov/archive/bisc/stiltsville/stiltsvillemaps.htm
........or, any number of locations in the Keys where a high tidal flow inlet is not a factor.
The War replica is not wholly abandoned. When I finish Yacht Design School, I will design one. The periscope depth comment is a function of design. What is a military boat for?.... but to approach it's target by stealth.
At snorkel depth, dynamic flow over dive planes, and deck effect would make depth keeping easier with the diesel. As previously discussed this would require high flow ventilation and compartmentalization. So a snorkel boat it would be, as this would not be asked to hold precise station in the water column. 

A neat toy with little real use like say a P-51 replica!  :)

Joe



From: "Rick and Marcia" <empiricus@telus.net>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: Re: [PSUBS-MAILIST] Drag
Date: Thu, 21 Sep 2006 10:56:18 -0700
Hi, Joe - ok, now I get it. Your priority is "putzing around the reefs". I 
see why the streamlining is less a priority.

If I remember your area there's a lot to see very close by.  I take it your
"mission requirements" have changed.

I'm still curious about the replica boat you started out with.  It was a
beauty.  Why would you be restricted to periscope depth?

Rick L



----- Original Message -----
From: "Joseph Perkel" <joeperkel@hotmail.com>
To: <personal_submersibles@psubs.org>
Sent: Thursday, September 21, 2006 4:10 AM
Subject: Re: [PSUBS-MAILIST] Drag


> Hi Rick,
>
> Yes been awhile....busy at home and with studies, but always time to jump 
on
> the learning curve here as applicable.
>
> Sure...to explain. Simply that any equation where "drag" and it's
different
> types (as there are various types of drag), ....in all cases, velocity is 
> the variable with the most effect.
>
> For example.....
>
> drag force = ½&#961;V2 × coefficient of drag × area  (where &#961; (the
> Greek letter "rho") is the density of the fluid)
>
> Notice that the velocity component is squared.
>
> This does not need to be calculated for a particular PSUB, it is simply to 
> demonstrate the velocity component.
>
> So if I am puttsing around in my little K-sub along a reef @ < 2kts, I
need
> not worry much about appendages like a manipulator, ROV cage, specimen
> basket...etc, causing excessive drag, it's not a worry. Entanglement
safety
> will have to be compensated with operational guidelines / limitations.
>
> However, as you remember my original concept, (the diesel electric
ambient),
> that would have been subject to streamlining to take most advantage of
> theorectical hull speed... Hull Speed = 1.34 * (LWL)1/2. Where with a LWL 
> of 22', would have been 6.29 kts, on the surface.
>
> Since then, I'm convinced that I am better off with a k-350 based,
research
> capable submersible for this area. I will have more utility and fun with
> that than the War replica, which would only be good for sneaking around at 
> periscope depth (fun to scare boaters perhaps) but, a potential for
> collisions and other problems.
>
> One caveat, I've not yet calculated power and thrust requirements. I see
> that I will need to account for a theoretical prevaling current, and
> determine what is required to "hold station" and "make way" against x
> current. Lot's to learn still.......
>
> Joe
>
>
>
> >From: "Rick and Marcia" <empiricus@telus.net>
> >Reply-To: personal_submersibles@psubs.org
> >To: <personal_submersibles@psubs.org>
> >Subject: Re: [PSUBS-MAILIST] Drag
> >Date: Wed, 20 Sep 2006 20:33:07 -0700
> >
> >Hi, Joe - it's been a while  :-)
> >
> >What do you mean by psubs speeds?
> >
> >Rick L
> >
> >
> >----- Original Message -----
> >From: "Joseph Perkel" <joeperkel@hotmail.com>
> >To: <personal_submersibles@psubs.org>
> >Sent: Monday, September 18, 2006 6:10 PM
> >Subject: RE: [PSUBS-MAILIST] Drag
> >
> >
> > > Kory,
> > >
> > > Always a worthwhile effort of course.... and a good point!
> > >
> > > Some degree of "streamlining" and or stabilization / tracking, may in 
> >fact
> > > be more useful for surface towing at 4 - 5 kts. But for submerged ops > > > induced / parasitic drag would still remain negligible at psub speeds 
as
> > > demonstrated by JSL, and a host of other research submersibles.
> > >
> > > Still....at this point, I expect to have a fair amount of protrusions, 
> >so
> > > preset operational guidelines / limits will have to make up the
> >difference
> > > for safety as you point out. Reasonable free ascent parameters will be 
a
> >big
> > > part of those guidelines as well as pre-dive planning.
> > >
> > > Joe
> > >
> > >
> > > >From: "kory mosteller" <hardcoremosteller@hotmail.com>
> > > >Reply-To: personal_submersibles@psubs.org
> > > >To: personal_submersibles@psubs.org
> > > >Subject: RE: [PSUBS-MAILIST] Drag
> > > >Date: Sun, 17 Sep 2006 20:45:58 -0700
> > > >
> > > >
> > > >for me, the streamling isn't so much for drag, as to reduce the risk 
of
> > > >entanglement.  it's always the last thing you expect that gives you
the
> > > >most grief.
> > > >-km
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >>From: "Joseph Perkel" <joeperkel@hotmail.com>
> > > >>Reply-To: personal_submersibles@psubs.org
> > > >>To: personal_submersibles@psubs.org
> > > >>Subject: RE: [PSUBS-MAILIST] Drag
> > > >>Date: Sun, 17 Sep 2006 23:12:30 +0000
> > > >>
> > > >>
> > > >>
> > > >>Nothing demonstrates Jay's statement quite like the JSL.......
> > > >>
> > > >>
> > >
> >
>>http://oceanexplorer.noaa.gov/explorations/05deepscope/logs/aug31/media/ei
> >ts_on_sub_rs.html
> > > >>
> > > >>This submersible convinced me not to bother with fairings for the
> >external
> > > >>air cylinders and battery pods.
> > > >>
> > > >>Joe
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>From: "Jay K. Jeffries" <bottomgun@mindspring.com>
> > > >>Reply-To: personal_submersibles@psubs.org
> > > >>To: <personal_submersibles@psubs.org>
> > > >>Subject: [PSUBS-MAILIST] Drag
> > > >>Date: Sun, 17 Sep 2006 19:00:14 -0400
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>At the typical speeds a PSUB travels at, protrusion drag is very
> >small.
> > > >>There are other issues you should focus on.
> > > >>
> > > >>R/Jay
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>Respectfully,
> > > >>
> > > >>Jay K. Jeffries
> > > >>
> > > >>Andros Is., Bahamas
> > > >>
> > > >>
> > > >>
> > > >>It is the mark of an educated mind to be able to entertain a thought 
> > > >>without accepting it.
> > > >>  - Aristotle
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>From: owner-personal_submersibles@psubs.org
> > > >>[mailto:owner-personal_submersibles@psubs.org] On Behalf Of
> > > >>ShellyDalg@aol.com
> > > >>Sent: Sunday, September 17, 2006 6:52 PM
> > > >>To: personal_submersibles@psubs.org
> > > >>Subject: Re: [PSUBS-MAILIST] Flow testing-freeboard and swamping.
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>Ron. Keep adding your 2 cents. I was thinking of a way to add
> >inflating
> > > >>ballast to give more freeboard when at the surface. Maybe hidden
> >behind
> >a
> > > >>retractable fairing to minimize drag when submerged.
> > > >>
> > > >>
> > > >>Frank D.
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > >
> >
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