[PSUBS-MAILIST] Props for Korts

Smyth, Alec Alec.Smyth at covisint.com
Mon Nov 11 11:14:53 EST 2013


Well... actually a prop would be pretty hard to print. The reason is the object you're printing has to have support as it builds, and overhangs are an issue. You can have overhang if it's at an angle, but it has to be a gradual overhang rather than something entirely unsupported. Picture a climber going up a cliff. You could print the cliff even if it slopes backward a bit, but you could not print it if the climber gets to a 90 degree "corner" from which the cliff he is climbing abruptly turns into a "ceiling" that extends out from the mountain without support.  

Maybe one could build the blades individually, standing on their outside edges, and put them on a hub. In fact that is a good way to make statically adjustable-pitch props, which is what I'm hoping to do. Something like this: http://www.google.com/imgres?imgurl=http://www.silent-submersion.com/Instructions/props/P8040170.JPG&imgrefurl=http://www.silent-submersion.com/Instructions/props/&h=453&w=283&sz=28&tbnid=oDDGGDQ9VGYHcM:&tbnh=93&tbnw=58&zoom=1&usg=__SpadE0b3zIAg1smJNHaGjW7wuvY=&docid=2eSkxXfumVGSnM&sa=X&ei=zAGBUuWCJOGbygGOt4GYBA&ved=0CGMQ9QEwBQ

Or, far simpler, we could just locate adjustable scooter props like the one pictured and get them off the shelf.


Best,

Alec

-----Original Message-----
From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Joe Perkel
Sent: Sunday, November 10, 2013 7:14 AM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Props for Korts

Pete,

Yes, a square tip custom prop is required and my drawings indicate this.

I've never had a minn Kota prop in my hands, but my understanding is that they are also ABS plastic.

That being the case then anyone with 3d printing capability can produce replacement parts at will. All that's required is the appropriate 3d model configured to the limitations of the printer.

Joe

Sent from my overpriced 
iPhone

On Nov 9, 2013, at 10:04 PM, Pete Niedermayr <freepetesub at yahoo.com> wrote:

> I've been reading up on kort nozzles. I'm under the impression that  the prop design is an intergral part of a kort nozzle. ie shroud plus prop equals kort nozzle. 
> What about the prop design? How does an off the shelf prop effect the performance of the kort nozzle ? Do we need to be talking about prop design and fabrication as part of a kort nozzle?
> --------------------------------------------
> On Sat, 11/9/13, Emile van Essen <emile at airesearch.nl> wrote:
> 
> Subject: Re: [PSUBS-MAILIST] Printed Kort Nozzle
> To: "'Personal Submersibles General Discussion'" <personal_submersibles at psubs.org>
> Date: Saturday, November 9, 2013, 8:17 AM
> 
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> E-Mail Software 6.0
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> The
> prototype was printed.
> I machined the final version from solid POM /DELRIN for
> better reliability 
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> A
> Kort nozzle on the
> other hand, would be extreme inefficient to machine from
> solid.. 
> 
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>   
> 
> Emile
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> 
> Van:
> Personal_Submersibles
> [mailto:personal_submersibles-bounces at psubs.org] 
> 
> Verzonden:
> zaterdag 9 november
> 2013 11:02
> 
> Aan: Personal
> Submersibles General
> Discussion
> 
> Onderwerp: Re:
> [PSUBS-MAILIST] Printed
> Kort Nozzle 
> 
> 
> 
>    
> 
> Hi, just
> to show you the possibilities: 
> 
> The black part forward the eyemask, means th part were the
> four hoses
> goes in - is a 3D print out. The diver was
> with it down to
>  260 feet .
> 
> 
> 
>  http://www.euronaut.org/content/gfx/diving/oxydrant/DoublellopwithPeppers001.jpg
> 
> 
> 
> The printer use a plastic wire with was print out hot
> melted. 
> 
> 
> 
> vbr Carsten
> 
> 
> 
> 
> 
> "Alan James" <alanlindsayjames at yahoo.com>
> schrieb:  
> 
> 
> 
> 
> 
> Hi
> Alec, 
> 
> 
> 
> 
> 
> It
> would be a matter
> of putting as much fiber in with the resin that
> the  
> 
> 
> 
> 
> 
> form
> would enable.
> With the kort nozzle, the nozzle shape would
> allow 
> 
> 
> 
> 
> 
> for
> a thick mix, but
> the struts might not. 
> 
> 
> 
> 
> 
> A
> bit of
> experimentation would be required. 
> 
> 
> 
> 
> 
> If
> you back lit the
> printed shell you may be able to see the resin as it fills
> it, 
> 
> 
> 
> 
> 
> &
> be aware of
> any air voids. Again with the thicker mixes you could ram
> rod 
> 
> 
> 
> 
> 
> them
> down with a
> flexible piece of plastic rod.  
> 
> 
> 
> 
> 
> One
> concern is that
> epoxy shrinks when setting, (but not as bad
> polyester) 
> 
> 
> 
> 
> 
> &
> so the shell
> might need to be filled in a coupe of pours to stop it
> damaging the outer
> shell.  
> 
> 
> 
> 
> 
> Alan
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> 
> From:
> Private
> <alecsmyth at gmail.com>
> 
> To: Personal
> Submersibles General
> Discussion <personal_submersibles at psubs.org>
> 
> Sent:
> Saturday, November 9, 2013
> 10:23 AM
> 
> Subject: Re:
> [PSUBS-MAILIST]
> Printed Kort Nozzle
> 
> 
> 
> 
> 
> 
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>   
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> 
> Sorry,
> the ones I was referring to are LONG fibers mixed with the
> resin. 
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> On Nov 8, 2013, at 4:21 PM, "Smyth, Alec" <Alec.Smyth at covisint.com> wrote: 
> 
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> 
> That's
> stuff is exactly what I meant by "structural
> fiberglass". You can't pour it. However, if you
> made the nozzle in two
> halves like doughnut-shaped dog bowls, you could fill them
> both up, put them
> together, and wipe off the excess. 
> 
> 
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>   
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> On Nov 8, 2013, at 4:17 PM, "Alan James" <alanlindsayjames at yahoo.com>
> wrote: 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Alec
> / Joe, 
> 
> 
> 
> 
> 
> these
> products
> "milled glass fibers" or "chopped strand
> glass fibers" 
> 
> 
> 
> 
> 
>  may
> be OK, in combination
> with epoxy resin. 
> 
> 
> 
> 
> 
> http://www.fiberglasssupply.com/Product_Catalog/Fillers/fillers.html
> 
> 
> 
> 
> 
> 
> The
> more you can
> add, the stronger the product, but also it becomes
> thicker 
> 
> 
> 
> 
> 
> &
> harder to pour
> in to small voids. I would be careful of using polyester
> resin as it 
> 
> 
> 
> 
> 
> would
> probably melt
> the printed shell. 
> 
> 
> 
> 
> 
> You
> may be able to
> use a thin flexible plastic rod to stuff courser mixtures
> down in to 
> 
> 
> 
> 
> 
> the
> shell. 
> 
> 
> 
> 
> 
> Alan
> 
> 
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>   
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> 
> 
> 
> From:
> Alan <alanlindsayjames at yahoo.com>
> 
> To: Personal
> Submersibles General
> Discussion <personal_submersibles at psubs.org>
> 
> 
> Sent:
> Saturday, November 9, 2013
> 8:10 AM
> 
> Subject: Re:
> [PSUBS-MAILIST]
> Printed Kort Nozzle
> 
> 
> 
> 
> 
> 
> 
>   
> 
> 
> 
> 
> 
> 
> 
> Alec
> / Joe, 
> 
> 
> 
> 
> 
> I
> will contact a friend who is in the 3d printing business,
> and try & find
> out a bit more 
> 
> 
> 
> 
> 
> about
> this application & casting materials. 
> 
> 
> 
> 
> 
> You
> would need to incorporate risers (tubes) in the design to
> vent air for the
> resin  
> 
> 
> 
> 
> 
> pouring
> process, & maybe " keys" on the inside of the
> mould to give the
> resin more 
> 
> 
> 
> 
> 
> grip
> to the printed shell. 
> 
> 
> 
> 
> 
> Cheers
> Alan 
> 
> 
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>   
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>   
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> 
> Sent from my iPad 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> On 9/11/2013, at 12:24 AM, Alec Smyth <alecsmyth at gmail.com>
> wrote: 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Hi
> Alan,  
> 
> 
> 
> 
>   
> 
> 
> 
> 
> 
> I
> like this idea! I have a printer I built myself so am a
> little familiar with
> them. One of the parameters you provide the printers on each
> job controls the
> "filling" of the piece. Normally, to save material
> that is a sort of
> cross-hatch, and the parameters control things like the
> direction and density
> of that cross-hatch. But the problem with that, for an
> underwater application,
> is that the resulting piece is full of air voids. I'd
> always assumed I would
> print something like this solid. However, if you print it
> hollow and fill it
> with structural fiberglass, the end result is going to be a
> lot stronger than
> if it's solid plastic. In addition, if we printed by
> parts but filled it up
> once those parts are assembled, the resin itself could be
> the "glue"
> that holds those parts together. 
> 
> 
> 
> 
> 
> 
>   
> 
> 
> 
> 
> 
> Thanks,
> 
> 
> 
> 
> 
> 
> 
> 
> Alec  
> 
> 
> 
> 
> 
> 
> 
> 
>   
> 
> 
> 
> On
> Thu, Nov 7, 2013 at 10:01 PM, Alan James <alanlindsayjames at yahoo.com>
> wrote: 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Joe,
> 
> 
> 
> 
> I
> was re thinking your idea of a printed Kort
> nozzle. 
> 
> 
> 
> 
> 
> There
> are printer kits for $900- that would do the
> job. 
> 
> 
> 
> 
> 
> http://www.3dstuffmaker.com/
> 
> 
> 
> 
> 
> 
> The
> ABS printer cable I've seen selling for about $1- an
> ounce. 
> 
> 
> 
> 
> 
> The
> $899- version in the above link could possibly be big enough
> to print 
> 
> 
> 
> 
> 
> the
> nozzle in one shot. If not then print it in sections &
> glue together. 
> 
> 
> 
> 
> 
> My
> idea is to print the nozzle hollow with an egg shell wall
> thickness & fill
> it with 
> 
> 
> 
> 
> 
> a
> fiber reinforced epoxy resin. The resin may need a few pours
> to allow for
> contractions 
> 
> 
> 
> 
> 
> in
> the resin while setting. 
> 
> 
> 
> 
> 
> Maybe
> under $30- in materials. 
> 
> 
> 
> 
> 
> I
> am not at the point where I need this & neither are you,
> but I think this
> idea still 
> 
> 
> 
> 
> 
> holds
> a lot of promise. 
> 
> 
> 
> 
> 
> Regards
> Alan 
> 
> 
> 
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> 
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> -- 
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> 
> 
>  Carsten Standfuß
> 
> Dipl.Ing.Schiffbau @ Meerestechnik
> 
> Heinrich Reck Str.12A
> 
> 18211 Admannshagen
> 
> 
> 
> 0172 8464 420
> 
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> 
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