Banner Ad 1

1/144 scratch build Akula

This is the place to post your submarine build- ups.

Re: 1/144 scratch build Akula

Postby bwi » Mon Jul 28, 2014 6:47 pm

Hi All,

The work on the Akula is on hold some time now as other projects around the house and garden took my full attention. Also my appetite to build was not so great to be honest.
Never the less I browse the SC forum on a regular basis......tonight though I had a giant bug that kept popping up through the keyboard (She is also one of the new projects that takes a lot of attention)......

Image

I know its of topic but I couldn't resist sharing this :D Sorry.

grtz,
Bart
Practical wisdom is only to be learned in the school of experience.
]"Samuel Smiles"
bwi
SubCommittee Member
 
Posts: 39
Joined: Sat Jun 01, 2013 12:25 pm
Location: Belgium

Re: 1/144 scratch build Akula

Postby Ober Freak » Mon Jul 28, 2014 6:52 pm

So cute
Ober Freak
SubCommittee Member
 
Posts: 73
Joined: Wed Jan 01, 2014 8:49 pm
Location: Hamelin, Germany

Re: 1/144 scratch build Akula

Postby bwi » Mon Aug 11, 2014 4:28 pm

Hi Gents,

As the appetite for the build slowly returns I'm mentally prepare myself to start scribing the hulls. The process past already several time trough my head....you know the stuff....witch tools I'm going to use, witch stencils I will make, witch floods and vents I will scribe witch ones I will open up, ....

But every time I get stuck when I'm thinking about the bow....how I'm going to project the torpedo doors to the spherical hull so the will end up as circle in a front view. I was thinking about making a mould of the bow in fiberglass and drill holes in it (will not be so strait forward) and use this as an stencil for the bow. But I'm not convinced this is the best way to go.

Yes I could use the try and error method an go for it but I would appreciate it if you guys share you experiences so I can skip the error phase :-).All suggestions are welcome!

Maybe we can list up all the experiences and place them under "Modeling Tips and Tricks"?

Thks and Grtz,
Bart
Practical wisdom is only to be learned in the school of experience.
]"Samuel Smiles"
bwi
SubCommittee Member
 
Posts: 39
Joined: Sat Jun 01, 2013 12:25 pm
Location: Belgium

Re: 1/144 scratch build Akula

Postby Ralph --- SSBN 598 » Mon Aug 11, 2014 5:42 pm

Maybe I can hep you a little here.

The bow is a compound curve sort of.
If you know cad programs of good with graphics you can make a pattern that is flat and came be bent around the hull to give the correct scribe line to make a circle as viewed from the front.
-
Now here is what I would try.
Get a piece of balsa wood that you can turn a round rod from.
Or if you can get a round rod to start with, do that.

Scribe tube center lines on hull.
Make a stand to hold hull stead.
Make a stand to hold wood rods at center of tube.
Then slowly sand the wood rod to the contour of the hull.
You will need a rod for each tube. Well, not each tube.
Some are the opposite of the others.

Once you have a rod that fits tight against the hull, dip it in some thinned wood sealer.
I actually use thinned glue.
Sand rod back to proper diameter and use as a scribe guide.

I might even drill a very small hole center of each tube and put a centering pin in each wooden rod so it can not be pushed off center when scribing.
----------------------
Another way would be to make a guide that has a floating scribe tool over it.
Say a brass rod with a centering pin to go in that hole in the center of the tube location.
Then use another tube that fits tight over the guide rod and put a scribe pin on it that can float with the curvature of the hull as you turn it around the guide rod.

Using the stand to hold the gude rod level and straight to hull, slowly turn the scribe pin until you have a good line.
Ralph --- SSBN 598
Registered User
 
Posts: 85
Joined: Tue Oct 23, 2012 5:11 pm

Re: 1/144 scratch build Akula

Postby bwi » Sat Oct 18, 2014 3:10 pm

Thks Ralph


Hi gents, the apatite is back….so the build is back on track.

A drill press was missing on my machinery list, and this was an item I needed for manufacturing the rudders and dive planes. I did not need a big machine but I wanted one with high precision. After streaming the WWW I found one for my budget I wanted to spent with a max clearance of 0.02mm on the spindle.

The masters of the rudders and dive planes were still were I left them…sitting in the modeling clay.

For the making of the sprue channels I modified a syringe so I got the desired diameter for the channels. Filled the syringe with molding clay an out came the channel.

Image

I cut the cylindrical formed clay in half longitudinally and pressed them in place on the mold.

Image

Image

The mold were closed and the seams were sealed with modeling clay. The poor funnels I made out of paper, put in place and sealed with molding clay.
The silicone was degassed in my DYI vacuum chamber (works Great!) and poured into the molds.

Image

Image

After curing molds were opened up and master and molding clay was removed. The only thing I needed to do before pouring the other half is making new sprue channels in modeling clay and put them in place together with the masters……and apply release agent . Closed and sealed everything and poured the other halve. The mold worked out fine.

Next step is to pour the resin in the molds, again I made the pour funnels out of paper. After the molds were filled I placed the in my pressure chamber @ 3bar, and let them cure overnight. I was very pleased with the result.

Image

Image

Image

Image

The only thing I noticed is that the diving plane was slightly bent but the master was straight. Probably I applied to much force when I pressed the master in the modeling clay as the rudder is long and thin it is fragile (lessons learned :oops: ). The deformation small so I don’t need to redo it.

Next step was to cut the control faces out. Everything was marked in pencil. On the real sub all the rudders and diving planes are provided with trim surfaces these are supported by pintle bearings. I want to integrate these bearing in the model. So these were also drawn.

First I had to drill the rudderstock holes (drill press time). As the rudders and dive planes are double curved it is hard to clamp them in a machine vice without a sort of jig. As I had a lazy day I din’t want to make a jig, so I tried……….modeling clay. This works great, just put an piece of modeling clay on both sided and clamp it in the machine vice, the modeling clay squeezes itself in place wen pressure is applied. 2mm holes were drilled.

Image

Image
The yellow stuff is the molding clay

The surfaces were cut out with a scroll saw. Before I made the cut I had to level the planes in both directions in order to get a nice vertical cut. This was done with modeling clay (yes I seem to use this stuff for everything :D ). A recess for the pintel bearing was also cut in the control surface. All cut surface were sanded. A radius was sanded on the leading edge of the control surface.

Image

The pintle bearings (3x5x5mm) were made out of a 3mm styrene sheet glued in place and provided with a 2mm hole.
The gaps between the control surface and the actual plane were filed up with the EUREKA putty but not before I thickened up the leading edge of the control surfaces by masking tape (4 layers approx. 0,5mm) and applied some release agent so the EUREKA putty will not bond with the tape.

Image
pintle bearing in place and tape applied

Image
EUREKA putty applied

Image
Control surface removed

After curing all were sanded in shape resulting in a nice small 0,5mm gap. The upper and lower gap between the control surface and plane needed also attention. EUREKA putty was applied on top and bottom and after curing sanded in shape resulting in a nice small gap.

Image

Bushings will support the rudderstock, I made them out of a 3mm brass rod, the all received a 2mm hole.
• 4pc for the pintle bearings (rudderstock runs through it) Ø3x3mm
• 4pc for the upper bearing (protrusion of the hull) Ø3x10mm
• 3pc for the lower bearing Ø3x3mm
These bushings will be placed in position in the molds prior to the casting process so they will be imbedded in the parts after casting.

Image
bushings

That’s it for now,
Grtz,
Bart
Practical wisdom is only to be learned in the school of experience.
]"Samuel Smiles"
bwi
SubCommittee Member
 
Posts: 39
Joined: Sat Jun 01, 2013 12:25 pm
Location: Belgium

Previous

Return to Builder Threads

Who is online

Users browsing this forum: No registered users