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Author Topic: 32nd Parallel XXI  (Read 12086 times)

Davy1

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Re: 32nd Parallel XXI
« Reply #25 on: June 06, 2014, 09:23:40 AM »

Hi Tom,

That's good.

The Darnell XXI has splayed shafts as per the original. I have extended the rudder forwards backwards and downwards with some slight improvement in turning circle. At the moment it is in clear polycarbonate but that is not fooling anyone!

I would suggest certainly extending the rudder forward and perhaps leave it at that. (Depending on how much you value scale.)

On the plus side, she turns quite quickly when stationery using the props. So you can get out of a tight spot on the pond!

Hope this helps you at this stage of your build.

David
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Davy1

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Re: 32nd Parallel XXI
« Reply #26 on: August 04, 2014, 01:52:01 PM »

Hi All,

Just an update on this and the Type XXI turning problems:

This version worked quite well but is not awfully scale and the "Yachties" in my club the Furness MBC pointed out that it was a "brake."



This version met the "Yachties" approval and turns her quite well. Also easy to remove.



This photo taken at the Norwich Sub Weekend 2014 (More photos and videos on the AMS Forum.)

David
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Subculture

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Re: 32nd Parallel XXI
« Reply #27 on: August 04, 2014, 02:08:49 PM »

Not great in shallow pond though. How about a triple rudder arrangement. The two out rudders would be in the prop wash, and it won't extend the draught.

Or perhaps if you had an auxiliary thruster e.g. a pump jet pushing though a slit in front of the existing rudder that only came on past say half rudder. More complex.


TomP

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Re: 32nd Parallel XXI
« Reply #28 on: August 04, 2014, 03:12:09 PM »

 I have been thinking of pivoting the rear of the boat like the picture so the rudder would then be in the prop wash just an idea may or may not work
 
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Davy1

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Re: 32nd Parallel XXI
« Reply #29 on: August 04, 2014, 05:06:02 PM »

Hi Tom,

I'm sure that would work too - though it is always a trade off with complexity.

Those "Yachties" (or Rag and Stick chaps!) do know a thing or two. If you have ever sailed an R/C yacht they turn on a sixpence.

It also backs up my experiences with my R class sub. You seemed to need rudder below the hull ( in non-turbulent water perhaps. ) I even found the turn sensitive to trim - stern down gave a tighter turn.

The rudder extension is designed to "knock- back" if she touches anything.

David
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tsenecal

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Re: 32nd Parallel XXI
« Reply #30 on: August 05, 2014, 04:17:23 AM »

Just a thought, (and perhaps pure idiocy) but competition ski boats add a skeg at the middle of the hull to decrease the turning radius...


perhaps putting a removable translucent skeg on the bottom of the boat, mirroring the sail, so they work together when the sub is submerged...
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Davy1

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Re: 32nd Parallel XXI
« Reply #31 on: August 06, 2014, 08:50:52 AM »

No, not idiocy that obviously works. Also rather like the centre board of a sailing dinghy.
However the difference between surface skimmers and submarines is the very big difference in the displacement of the hull. A sub has the whole length of the hull several inches under water so probably more difficult for a skeg to function unless it is very big.

David
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Dave J

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Re: 32nd Parallel XXI
« Reply #32 on: August 09, 2014, 10:16:00 AM »

You could also consider putting universal couplings between the shaft and propellers and with a mechanical linkage to the rudder with only a few degrees of side movement will improve the turning circle.
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TomP

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Re: 32nd Parallel XXI
« Reply #33 on: January 22, 2015, 11:25:38 AM »

Not given up been a little busy saving pennies for a new garage in the garden, roof going on this weekend so hope to carry on building in a few weeks. Wife has taken over my current garage for dog grooming so I'm building this for myself, insulated with heating a better lighting and space for a lathe finally



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Subculture

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Re: 32nd Parallel XXI
« Reply #34 on: January 22, 2015, 12:44:34 PM »

Are you building a workshop or a mausoleum? ;)

spooksgone

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Re: 32nd Parallel XXI
« Reply #35 on: January 22, 2015, 02:23:22 PM »

Nice one Andy. I did begin to wonder where tomp had got too.
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essex2visuvesi

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Re: 32nd Parallel XXI
« Reply #36 on: January 22, 2015, 08:30:13 PM »

insulated with heating a better lighting and space for a lathe finally



Better than room for a pony  ;D
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TomP

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Re: 32nd Parallel XXI
« Reply #37 on: March 12, 2015, 08:25:46 PM »

Man cave nearly ready not long now I can get back to building.
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spooksgone

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Re: 32nd Parallel XXI
« Reply #38 on: March 13, 2015, 08:12:40 AM »

Looks ideal Tomp. Have you got a kettle in there? I can't build anything with out a cuppa, not that I build much these day's. oh, and chocolate bisquits of course.
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Tug-Kenny

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Re: 32nd Parallel XXI
« Reply #39 on: March 13, 2015, 10:09:15 AM »

If you are wiring it up don't forget to put the fuse box near the door.   That way, when you close up for the day, everything can be switched off in one go.

I have this system but  'er indoors'  always trips out afterwards to check on me.   %)

ken
 
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TomP

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Re: 32nd Parallel XXI
« Reply #40 on: April 26, 2015, 10:46:17 AM »

Workshop nearly complete just a bit of painting but at least can start building again

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Tug-Kenny

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Re: 32nd Parallel XXI
« Reply #41 on: April 26, 2015, 11:06:17 AM »


Very nice in steel.  I'll bet you're looking forward to some 'time out'.  I like the 'Hi Fi'.     Is it for the vertically challenged ?    {-)

Cheers

ken
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