Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[ScottW]

Okay, let's do an official 'build log' for a rubberband powered balsa wood submarine.
Model is second balsa wood submarine inspired by a project in a 1970s book parents got me back in school days.
Submarine there was built of balsa planks, blocks, sheets, with bent tinplate prop and rudder. However after procrastinating around 30 years I built a much more sophisticated model in 2005-6.

Current project got its first parts cut and assembled in 2008 then spend between then and now being worked on in spurts between years of inactivity.
With having to give up participating in model railroad club I've recently started more intently working on it.
This build is to be 3 feet long, twin screw, freelance design with shape inspired by a bit of Typhoon/Red October & the NNemo2 by Newport News Shipbuilding division of Northrop Grumman.
See photos in: https://www.semanticscholar.org/paper/SIMULATION-OF-A-NON-AXISYMMETRIC-UNDERSEA-VEHICLE-A-Hess-Faller/d1f839ed416da9ef35bf63d4eaa1ce8ffea5dda5

Propellors/screws are circa 2005-6 with one right and one left rotating by Traxxis for a RC deep vee they had at the time.  One of those props does admirably on the single screw build from 2005 which will go Olympic pool length on 300 winds with 1/2 to 3/5 the distance submerged depending on how many winds and on the bow plane setting.

[ScottW]

Along the way a more military looking single screw one was built for neighbor Bobby around 2007, 08.

[ScottW]

Okay, back to the 3 foot build. The photos can do the talking.
Hull is free-flooding so that is why so many vents and drains.

[ScottW]

A bit more to catch up to current state.

A 'primary feature' of its styling will be a few selected anachronisms.

Around 01am Saturday a button got turned in to a hatch which was inspired by a feature of Germany's modern U212 type.
See: https://www.seaforces.org/marint/German-Navy/Submarine/Type-212A-class.htm

[Alan52]

Hi Scott


Just found your build log. What a fantastic job you have made. I always admire people who can build from plans and scratch build. Unfortunately I am not that skilled in that area.


Great Job mate


Alan

[ScottW]

Just found your build log.

That recent find is only because it was created an hour ago!
Thanks Alan!
Don't let my secret out but a lot of this one is being designed as it goes along.  Finally last week settled on what to do for rudder/rudders.
Now the details of how to build them need to be worked out.

Stern planes are still a mystery. They need to: 1, be adjustable; and, 2, not have shafts which interfere with rubber bands and prop shafts.

For a long time there was intent to give the thing an assortment of working lights. That is a bit iffy right now. Much less work to not have them. But having them would be so cool. But not having them is so much easier and no access openings need to be cut in the hull structure. But last week I found some watertight battery containers on Amazon and there is an idea how they can be mounted for exterior access from the bottom.


And finally, scratchbuilding is a whole lot simpler when building to "sport scale" or "toy scale"; especially when construction is all welded and there are no rivets to have certain specific quantities of.

[Alan52]

Hi Scott


Do the lights, you will kick yourself later if you don,t. It’s looking impressive. Good luck with the stern planes . I wouldn’t know where to start.


Alan

[ScottW]

Do the lights, you will kick yourself later if you don,t. It’s looking impressive.

I'm leaning that way again. Remember though, these projects are being done with a body which can prevent anything more complex than daily existence from being done for periods of days to entire seasons.

However ...

This is one of the waterproof battery holders found, https://www.amazon.com/Adafruit-Waterproof-Battery-Holder-Switch/dp/B071H8R6R1/

And current thinking is that with frame cross-section depth being what it is there is allowance to inset one of these in hull bottom each side of external box keel. And under the balsa blocks which form conning tower and sail so battery weight could offset some of their buoyancy - but will 2 AA even be enough weight to offset what buoyancy the battery boxes themselves may have?
Photos show hull bottom & a bit of shot for ballast added. Will take far more than that even with hull being frames and skin as opposed to PRS-1's hull of blocks, slabs, and thick plank for hull bottom; even with an open free-flooding hull it is heavier than most people expect.

Anyway, guess the only way to find out is buy battery boxes from next month's income, try them and find out.

Lights themselves will be LED pirated from Christmas lights.  An array of white lights in bow for illumination when docking with undersea colonies; a few other lights; & some but not all of the navigation lights.  Spectators might like the flashing yellow beacon subs of today use for surface navigation but I've got autism and a few other neurological things going on and flashing lights get on my nerves real quick, quick enough that there is no television in my home.

But yeah, it would look very cool lit up like something from another planet.

And be a trip to run at night if that option ever presents itself.

Oh, pair of large round holes is access to where forward ends of rubber band motors will be secured.

[ScottW]

Made some bite-sized progress today; got fairing for base of folding snorkel glued on.
Fabricated it in similar bite-sized sessions Saturday and Sunday.  The rust color material is Bondo glazing and spot putty. Grain was sealed, somewhat, by dipping part in shellac. Then after a bit more sanding the putty was used to smooth the surface again.
Will eventually be painted with a sealing coat of clear gloss brushing lacquer, in this case made by Minwax.
True, the fairing's leading edge could be more streamlined but this is the look my brain desired. And it is in the wake turbulence of the base of the sail anyway ...

[ScottW]

Do the lights, you will kick yourself later if you don,t.

That keeps on sounding more and more Right.
So ... (while it is 4 am now in UK it is only 10 pm here)

I took a gift card from my parents which had some remaining money and ordered those battery holders since website said 11 currently in stock.
Amazon page had dimensions which allowed a couple templates to be cut.
Battery holder is said to be 3/4 inch thick. Frame depth is 1/2 inch. Hull skin is 1/8 inch.
Holders can be inset to hull frame depth.
Then have an exterior fairing which echoes upper fairing.
That would allow depth for a removable skin panel to smooth exterior and reduce turbulence at that location.

How about placing them right there?  (as in attached image)


It now appears that a plan may have come together. 

[Alan52]

Hi Scott


I am no expert, but that looks like the right position to me. The lights will definitely make it a real eye catcher. Coming on well mate. Great job.


Alan

[ScottW]

Thanks Alan! 
No progress on PRS-2 today, but the PRS-1 crew are finally getting those handrails they've been nagging me about since the boat left the ways in 2005.

Oh, and after several years of pondering painting, PRS-2 will receive same colors as PRS-1.
Guess that will be my 'official style' for subs built to imaginary designs.

[Footski]

A most impressive build and wonderful imagination to go with it. It looks like a lot of fun, interspersed with some headaches…

[Alan52]

Looking great Scott. I like the colour scheme 

[ScottW]

It looks like a lot of fun, interspersed with some headaches…

Thanks! 
It is great fun, even the designing is a form of play.
One or two minor headaches give a satisfaction of challenge and resolution; more than that take the fun out of a project.

[ScottW]

Looking great Scott. I like the colour scheme 

Hey, good morning, well, 8:55am in our time zone. 
Thanks!
However it was that came to be PRS-1's color scheme in 2005 it does turn out to look attractive both in the water and on the shelf.
While waiting to begin a sleep study at neurology clinic last week I had brought along sketchbook and colored pencils and put PRS-2 in to that livery.
Am really looking forward to reaching point of paint and decals yet feeling somewhat intimidated by this thing's size with its three foot length.

[ScottW]

Periscope and antenna progress. There will eventually be scope 2 mostly retracted between scope 1 and antenna mast.
Bases of scope 1 and antenna mast go an inch or so in to balsa block of sail/fin/fairwater/whatever else submariners have ever called the structure.
Just like with PRS-1 the scopes and antenna do not retract and do not remove.
Unlike with PRS-1 these end in solid rod instead of being open tube which goes all the way in to free-flooding hull interior and sometimes emit bubbles as sub dives below periscope depth.


Am still pondering how exactly I want to do red and green navigation lights on sides of sail.
Need to find a happy balance between what would look cool and how much it would make my hands hurt to do it.

[ScottW]

Rubber band anchor point, motor peg, whatever it can be called is almost done.
This is inside the upper hull half.
Final rod will be brass so as to stall off bimetallic corrosion. Stainless rod was used for visual contrast for construction process and for photo.
Will be 2 motors with each being 3 loops of 3/16 inch wide tan sport rubber for model airplanes.
I've not a clue what the numbers would be but that will put some torque on those new larger props which arrived Friday.

With motor anchor being slightly above hull centerline there will be a very slight angle down to the props.

[ScottW]

Instead of progress on the twin screw PRS-2 there has been progress on the 3ft long PRS-3.
Top of hull and the casing had been cut and assembled a few years ago.
Hull has only been designed to about 1.5 inches down from top, below that it remains loosely defined, still needs actual design.
Its look is being inspired by 1913 to 1915 U-Boats.

PRS-3 may be fitted out as a combat sub with deck guns. With or without guns it will carry the circular platforms.

Might carry enough rubber motor to cross a city park pond in a neighboring burg.

[ScottW]

I splurged on a book. Amazon had it on sale for about 23% off.
https://www.usni.org/press/books/us-submarines-through-1945-0

U.S. Submarines Through 1945
An Illustrated Design History

By Norman Friedman

    Subject: Fall 2021 Catalog | Friedman's Illustrated Design Series | Submarines | Drachinifel YouTube Channel - Reading List
    Format: Hardcover
    Pages: 400
    Illustrations: 144 photos, 102 line drawings

Dad got the US Naval Institute's Proceedings magazine when he was in during cold war.
Lots of interesting stuff in there.
And some quality art and photography.

The issues I had kept got water damage in a 1990s apartment fire.

[ScottW]

And speaking of books, paging through The Illustrated Directory of Submarines of the World the photos of early French subs reminded me that the life rings, though oversize, on each side of PRS-1's conning tower are not fictional, they are French!
Well, at least inspired by photos in that book of French subs doing likewise in the 1914 to 1920 era.

Found examples online,

https://upload.wikimedia.org/wikipedia/commons/4/40/Romazzotti-Marius_Bar.jpg
and
https://naval-encyclopedia.com/wp-content/uploads/2018/01/Lagrange.jpg

Above image comes from this page,
https://naval-encyclopedia.com/ww1/France/submarines.php
See also submarine DA in page header.

[ScottW]

While there is still about 1/2 hour left in August 31 in our time zone, the End of August Question is,

How much money do I want to spend over time, meaning this winter, for details for PRS-3?

Specifically the deck guns like these 3D prints found,

(and also some of the guys)

https://www.shapeways.com/designer/southwestforests/lists/1-72-scale-figures


Or, are there appropriate metal guns which would be more durable though less detailed?


Or, can I scratchbuild a 5 inch, a 40mm, and a 20mm, which would be inexpensive, durable, and keep the simplified toylike theme?


Decisions, decisions.

[Alan52]

With your skill Scott, I would say scratch build. You have made a fantastic job so far and I am sure you could make the guns.

[ScottW]

I would say scratch build.

Thanks Alan! 
While quite nice the 3D printed deck gun parts might be a bit on the brittle side for something which will be actively handled at times. And the primary theme here is fun and broken 3D parts would not be fun.

Now the 3D printed people, yes, I'll get some of them to place on the boat when it is on the shelf.

[ScottW]

And in the most recent episode of "Found while looking for something else", a couple things I thought were no longer in my possession: photocopies from publisher US Naval Institute of ship camouflage articles from 1970s issues for their Proceedings magazine which Dad got while he was in USN during the Cold War.
I called USNI and ordered in mid 1990s after losing original magazines in either a move or when apartment above me burned at beginning of 1990s.
At the time I had begun a new job and it turned out a couple coworkers were working up a set of rules for WW2 naval miniatures wargaming.
So of course I had to get involved!
They knew of ship camouflage painting but not the details of it.

Another thing in the envelope is a booklet bought at a classic combination hardware store-hobby shop in Missouri in late 1980s.

Also in the packet are what look to be my very first idea sketches for PRS-2.


Perhaps I should paint the 36 inch long PRS-3 in K-2/S-33's "pea green with three foot wide purple-violet stripes"?