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Re: [PSUBS-MAILIST] Posted my design too!



Erik,

I noticed a fairing or duct aft of the cockpit.  Is this designed to
smooth out laminar flow and reduce vortices? Have you done
any calculations to this effect? Or "will" there be a rear thruster ?

BTW,  I don't know if that url helped or not, but I noticed [ in my
browser ]
the illustrations were poor.  There is a pdf  file for this, too.  The
figures
are much clearer, but in BW.

PDF] ME 415 Group #5 Design of an Autonomous Underwater Vehicle Advisor
...
http://golem.math.stevens-tech.edu/auv/ME/DesignReport/meDesignReport.pdf


Did any of the computation formulas help?

--Steve



On Sun, 7 Mar 2004 01:51:56 EST DJACKSON99@aol.com writes:
> EM
> 
> What is the displacement? So the tubes on the side are the batteries 
> and soft 
> ballast, right?  Where is the weight? Also in the side tubes?  If 
> the weight 
> is not in the keel, I'd think it might list too easy to when your 
> existing the 
> hatch in the top, envy if your not Santa :)    Calculate your center 
> of 
> gravity for when your sitting on the hatch and make sure you not 
> going to tip over, 
> flood and sink.  Have you considered a bottom hatch and a wet entry?
> 
> Do I count 4 thrusters?  If the tail does not turn then do any of 
> the 
> thrusters?  Or are you planing on steering only buy thruster speed 
> and direction?  I 
> guess that can be done, but the control circuit will complex.  
> 
> No doubt it will be a lot cheaper to build than a 1 ATM, but 
> certainly no 
> less fun.  What materials are you thinking of using in addition to 
> the acrylic?
> 
> Puerto Rico sounds like a great place to be building a sub.  Are the 
> walls 
> close to shore?
> 
> With greetings from Oklahoma
> Doug J
> 
> 
> 
> 
> In a message dated 3/3/2004 2:48:51 PM Central Standard Time, 
> emuller@naic.edu writes:
> Thanks Doug for your comments, I can address a few of them right 
> away:
> I was actually planning to have separated ballast, i.e. a fore and 
> aft 
> separation in the middle of the big ballast tanks.
> 
> The tanks on either side will be linked, so that rolling is not 
> generated by an offset boyant force, although pitch trim can be 
> fine-tuned  depending on depleation of air tanks etc. Of course, I 
> might 
> end up adding forward planes anyhow.
> 
> Getting in and out will be through a hatch in the top (not for 
> santas). 
> There is enough ballast to give a freeboard of around 30-40 cm when 
> loaded up (I estimate). I envisage that the frame extending out that 
> 
> back can also be used to attach boyant modules to fine tune ballast.
> The V tail is simply a cop-out to try to get some stability mostly 
> against roll, since the projected resistive area against pitch and 
> yaw 
> is minimised for a 45 degree angle in the V and is maximised against 
> 
> roll. Since that part of the machine will be (probably) in more 
> turbulent flow a small x-section is preferable. Furthermore, It will 
> be 
> entirely passive. Steering (yaw and pitch) is achieved by motors 
> only. I 
> wanted to get away from dive planes because I live in puerto rico... 
> 
> there are big walls that I want to be near and be agile at low 
> speeds.
> 
> Since I am not using many heavy materials, that require much 
> machining, 
> I hope that it will be cheaper than the typical 1 atm sub. I think I 
> am 
> at more liberty to get things wrong and make a second attempt later 
> on. 
> I expect that it will be quite iterative.
> 
> Thanks again for your comments! Please let me know if I am proposing 
> 
> anything which cause your eyebrows to jump in 
> confusion/hysteria/contempt/disbelief!
> EM.
> 
> DJACKSON99@aol.com wrote:
> 
> > Greetings EM
> >  
> > Slick looking design.  Not the metal can I'm building :)   You 
> might 
> > consider reducing the displacement of the cabin in order to 
> decrease 
> > the amount of ballast required when you convert to dry? Maybe you 
> can 
> > use 2 canopies, one for hydrodynamics and the second for the air 
> > seal.  Since you're going to operate shallow you may want to 
> consider 
> > that light entering the top of the canopy will reduce downward 
> > visibility due to reflection.  You'll need a forward ballast 
> > compartment too, or you'll have to add dive planes and be more 
> like 
> > the Bionic Dolphin (www.bionicdolphin.com 
> > <http://www.bionicdolphin.com>)  And you need some way of getting 
> in 
> > and out without sinking once you strap on the ballast needed to be 
> 
> > dry, because your canopy opening will likely be below the water 
> line.  
> > Maybe inflatable pontoons or a small top hatch?  The v-tail is 
> cool 
> > and low drag but they require a mixer that will complicate the 
> build some.
> >  
> > Thanks for showing your design.  I look forward to seeing more.
> >  
> > Doug Jackson
> > www.jackson.parcabul.com/sub <http://www.jackson.parcabul.com/sub>
> >  
> > In a message dated 3/3/2004 8:10:40 AM Central Standard Time, 
> > emuller@naic.edu writes:
> >
> >     Hello folks,
> >     Due to pressure from un-named folks here (i.e. gauge 
> pressure),
> >     and the
> >     upcoming threat of competition by scubatron (i.e. absolute
> >     pressure), I
> >     have also posted some images of design plans for an ambient, 
> dry
> >     machine
> >     on moki.
> >
> >     I suspect I will take the construction in a two-step process,
> >     firstly by
> >     building a wet torpedo-like thing and checking how it all 
> works,
> >     construction methods etc. Then I will cover it over and blow 
> all the
> >     water out to turn it into a dry machine.
> >     Comments please??
> >
> >     EM.
> >


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