[PSUBS-MAILIST] Group Help Request

[Marc de Piolenc]

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?
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-- 
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