[PSUBS-MAILIST] Group Help Request

Mon Oct 28 13:14:16 EDT 2013

Joe,
Eight 12v batteries would just yield nominal 96 volts.  The configurations available change when you're connecting lithium batteries, so I'm not sure how they're getting the high DC voltages.  I've wondered the same thing, but haven't yet asked those in the group who have expertise in DC systems.  We commonly use inverters to convert 12v battery output to 120v AC, so using transformers seems reasonable.
Jim 

-----Original Message-----
From: Joe Perkel <josephperkel at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Mon, Oct 28, 2013 11:24 am
Subject: Re: [PSUBS-MAILIST] Group Help Request

Jim,

On attachment I can use suggestions from the group. But, I am envisioning a concentric ring surrounding the outer housing with a set screw or two. The supports come off of this ring and are supported on both ends by countersunk screws. All of this stuff made of the same ABS plastic exept the hardware.

On the Nuytco thruster, ... 4.5 hp turning a 12.1" propeller with 7.5" pitch @ 1200 RPM will push a 6,000 lb submersible @ 4.27 kts, So,... if we can enclose a  4.5 hp motor in a #6 Sch 40 pipe and turn that prop @ 1200 rpm, we can mimic this thruster. The problem is feeding the input voltage.

So my question then is, How is Curasub feeding those 200 - 400 vdc thrusters? Do 8 batteries connected in series give you 200 v? Or is there some type of step up transformer in play here? I am unclear on how this works.

Joe

From: "jimtoddpsub at aol.com" <jimtoddpsub at aol.com>
To: personal_submersibles at psubs.org 
Sent: Monday, October 28, 2013 9:39 AM
Subject: Re: [PSUBS-MAILIST] Group Help Request

Joe,

Another company that will give you quick quotes on printing a 3D object in a variety of materials is http://www.shapeways.com/.  

The Kort nozzle (the ring itself) doesn't necessarily have to be printed in one piece; it could be printed in two or three segments of the circle and joined together.  What material do you plan to use for the supports, and how do you plan to attach them to the motor housing?  The nozzle and the supports don't have to be of the same material, and printing the nozzle doesn't mean you have to print the supports.  Lots of options to consider.

There are services around such as http://www.lazerdesign.com/  that can do a 3D scan on an existing object and save a lot of CAD work.  You can also find desktop 3D scanners for sale such as www.makerbot.com/Digitizer.

Just for fun, take a look at Nuytco's MK-2 thruster:  http://nuytco.com/products/nmt12-mk2-thruster/

Have fun,
Jim

-----Original Message-----
From: Joe Perkel <josephperkel at yahoo.com>
To: personal_submersibles <personal_submersibles at psubs.org>
Sent: Mon, Oct 28, 2013 6:42 am
Subject: Re: [PSUBS-MAILIST] Group Help Request

I just love the world in which we live! Look what I found while waiting to take my daughter to school,.. http://www.quickparts.com/QuickQuote.aspx

Isn't that just the coolest thing! The Star Trek synthesizer in the real world.

Joe

Sent from Yahoo! Mail for iPad

From: Marc de Piolenc <piolenc at archivale.com>; 
To: <personal_submersibles at psubs.org>; 
Subject: Re: [PSUBS-MAILIST] Group Help Request 
Sent: Mon, Oct 28, 2013 10:46:58 AM 

Never thought much about doing it at small scale.

I suppose I would set up something like a wood lathe or a potter's wheel 
and work in some very soft material like low-density foam. Once I had 
the shape that I wanted, I suppose one could pour a mold around the 
master, melt or dissolve out the pattern and cast the final part in some 
suitable plastic, or even in aluminum if you were ambitious.

3D printing seems like the ultimate way to do it, though - the accuracy 
available is already better than what we would need, and if the inital 
results are not perfect, making changes and printing out another 
prototype is very quick.

Marc

On 10/28/2013 6:13 PM, Joe Perkel wrote:
> How can a home builder maintain that contour 360 Deg out of "X" material?
>
> Joe
>
> Sent from my overpriced
> iPhone
>
> On Oct 28, 2013, at 2:57 AM, Marc de Piolenc <piolenc at archivale.com> wrote:
>
>> Quick clarification: a properly contoured Kort nozzle, MARRIED TO A MATCHING PROPELLER, will increase static and low-speed thrust. Of course it won't increase power, since that comes from your motor. If you just put a shroud around your existing prop, you will be disappointed, and a shroud that doesn't do the job is overpriced unless it's free! Key ingredients for success:
>>
>> Prop matched to the shroud
>> Shroud matched to the speed and thrust requirement of the vehicle
>> Motor matched to the resulting prop
>>
>> Marc
>>
>> On 10/28/2013 8:33 AM, Jon Wallace wrote:
>>>
>>> What is the cost of having a true Kort nozzle machined by a CNC? I think
>>> a 30% improvement in thrust for $30 would be great but I suspect
>>> machining a Kort is going to equate to many hundreds of dollars, if not
>>> reaching beyond a thousand.  When I look at the Snoopy underwater videos
>>> it is difficult to imagine a kort nozzle really making any difference in
>>> the operational experience given that the motors are operating very
>>> slowly and pushing Snoopy around at about 2 knots (estimated).  The
>>> props are designed for power, but that's what we want underwater.  True,
>>> a kort nozzle would increase that power but what is the return on the
>>> cost?  In other words, on a road with a speed limit of 30mph and no
>>> passing zones it doesn't matter whether you have a 1.6 liter or 5.4
>>> liter engine under the hood does it?
>> --
>> Archivale catalog: http://www.archivale.com/catalog
>> Polymath weblog: http://www.archivale.com/weblog
>> Translations (ProZ profile): http://www.proz.com/profile/639380
>> Translations (BeWords profile): http://www.bewords.com/Marc-dePiolenc
>> Ducted fans: http://massflow.archivale.com/
>> _______________________________________________
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>
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>

-- 
Archivale catalog: http://www.archivale.com/catalog
Polymath weblog: http://www.archivale.com/weblog
Translations (ProZ profile): http://www.proz.com/profile/639380
Translations (BeWords profile): http://www.bewords.com/Marc-dePiolenc
Ducted fans: http://massflow.archivale.com/
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