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1/144 scratch build Akula

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1/144 scratch build Akula

Postby bwi » Tue Jun 04, 2013 1:22 pm

Hi gents,

First of all I want to apologise for the, probably 100+, grammatical errors that I will write, this thread will be in Belgian English.

Finally I have started with my long (I have ordered the plans in 1997 from deep sea designs “Greg Sharpe”) planned scratch building project of an akula submarine. I think I have read almost all the stuff that’s around on the web. In the nineties some names were all over the web with a lot of information David Merriman was such a name. In 2006 I have stumbled upon a very interesting project of Jerome Simon. In 2010 I have purchased Wayne Frey’s book “Russian Submarines” which is also a great help for my build. And of course many, many more….

I believe I have to give something back in return for all the lessons I have learned from you guys out there. So this was payback time and I decided to sign-up and join the SubCommittee.

As I have a family to take care of and a full time job the progress of my build will be slow but continuous, furthermore the appetite to build has to be there, for me it has to be relaxation not another stress building nerve wracking thing. No appetite no Build!!.

The scale I have chosen in function of transportation possibilities (we have small cars in Belgium :)). It had also to be hand carried with ease. So the easiest for me was to shrink the “deep sea designs plans” (1/96) 1.5 times so scale 144 was the outcome. The sub would measure 800mm [31.5”] what was acceptable for me. The scale was set; next the making of the hull.

As previous stated I have read the thread of Jerome Simon building his akula and this made my decision easy. I will make a master, make a mold from the master and finally lay-up the hull in the mold.

Making the master:

I have started out with some hard wood from the old windows of my house. First problem to tackle the dimensions of my lathe, distance between centres is only 400mm [16”], so I decided to make the master out of 3 pieces, each piece consisted out of two halves bolted together so I could separate them after the piece was shaped on the lathe. After the three pieces were shaped the halves have been separated and glued together resulting in a top half and bottom halve master.

The pieces were turned on the lath by hand. As a novice in wood turning I first made the pieces cylindrical and then made an recess every 10mm [0.4”] till I reached the correct diameter and finally removed the remaining material between two recesses. Next step was sanding the pieces, this resulted that everything was covered with a nice red carpet of dust in the basement/my workshop. And as I left the door to the basement open the carpet of dust continued in the living quarters of the house :( .

The pictures below showing the master halves; Cleary visible are the glue seems and boltholes for holding the halves together in the lathe process. The traces of bolts in the centreline of the master are remnants of the bolts applied for the centres of the Lathe. The masters have been coated with filler.

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This picture shows the plugs for filling the boltholes in the master (made out of a broomstick). Afterwards more sanding also the flat surface of the master halves to get an even seem between them.

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In between I have started with the rudders and dive planes. I have made them out of rectangular pieces of oak (what renovating a house is good for). Glued some copies of the drawing on top and started sanding and grinding till I had the wanted shape. The same I did with the housing of the towed array. Then applied some putty, filler and consequently some sanding & grinding.
The water intake scoop I have drawn up myself from pictures found on the web and in the book of Wayne Frey. They have been made out of two pieces of acrylate and grinded/sanded into shape.
I will cast all the above stuff in a later stadia of the project, after casting I will cut-out the actual surfaces of the rudders and planes. I will make the surfaces as large as possible especially the ones of the rudders in order to get a good turning rate of the sub.
Pictures below show the planes, rudders and water intake scoop.

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Next up were the SOCKS sensors, these I have been crafted without any drawings just by means of pictures and some guessed dimensions. See picture below (ruler indication = mm).

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So far this contribution …..I will update this thread when I made some further progress. Can take a while though…..No appetite no build, remember :D
Grtz,
Bart
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]"Samuel Smiles"
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Re: 1/144 scratch build Akula

Postby salmon » Tue Jun 04, 2013 7:00 pm

Very nice! Tak, Thank you and look forward to the next post (after you eat - of course).
If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.
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Re: 1/144 scratch build Akula

Postby bwi » Sat Jun 22, 2013 12:59 am

Hi Gents,

Promised to update this thread……..I have been eating quite well :D .....the appetite was there.

The plugs were glued in the bold holes with epoxy glue so far so good. Remaining gaps were filed with the same glue. Master halves where sanded and primer was applied, without remark.
The flat rear deck I have constructed out of a piece of 3mm [0.11”] Polycarbonate sheet….sanded one end down till I had a sharp edge for the rear transition with the hull. I have attached the flat deck to the hull by means of screws, one every 30mm [1.2”], so it followed the radius of the hull nicely. The gaps at PS and SB side, between the hull and the flat deck, I decided to fill up after the sail was installed.
On the sail I have cheated a little bid. A few years ago I have purchased a D**AS kit, never assembled it as it did not meet my expectations. I took the sail of the D**AS kit and used it on my present build. It was glued in place by means of epoxy glue.
I also used the glue to get the curved transition between the hull and sail and hull and flat deck. I thought this would do the job…..it did till I went sanding the stuff in shape. I will keep it polite…..never again that stuff is very hard to sand and the result is poor…surface can be compared with that of the moon :( . I have tried to rectify it by means of spray-on filler but the attempt has crashed en burned :( see pictures below.

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So I went looking for another product to finish the job. I remembered “**** metal glaze” works well but this product cannot be purchased in Belgium. I found a store that has specialized in Polyester, resins & fiberglass. After I had explained what I actually wanted (easy to sand and quick drying) I went home with an equivalent of the a.m. product……applied the stuff and went sanding…..after a few second one could see a very happy man in his basement :D....the stuff works great. As I don’t want to advertise for any brand in my building thread I won’t mention the product name. For those interested I can help out through a pm. Picture below; the white colour putty iwo the transition hull/sail is the EURIKA stuff. (still smiling as I write this down, I will remember the sanding of the epoxy glue for a very long time….if it doesn’t kill you, it makes you stronger I guess).

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When I was enjoying the view of my work, a bug settled in my brain. I took the drawings and noted that the sail runs horizontal for a while before it plunges towards the deck. Mine didn’t. I went through all the pictures and printed some details of the sail they only confirmed my findings. To rectify this I copied the ”as is” sail shape to a piece of 1mm [1/24”] styrene sheet. Then I copied the “to be” shape from the scaled drawing onto the same sheet. Next the difference between the two was cut out and glued onto the sail. See pictures below.

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The difference is small I know but visually its night and day. Then I applied the EUREKA putty to fill the gap…..in order to get the PS and SB side the same was hard but eventually it turned out fine. See below pictures; also note the sail has grown in length to. Memo to myself, next time no shortcuts!

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I have one question regarding the navigational mast radar, periscopes, etc…If anyone has some detailed drawings or pictures of them…they are very welcome. The only thing I have found is a good picture of the radar.

So far this contribution …..I will update this thread when I made some further progress. Can take a while though…

Grtz,
Bart
Practical wisdom is only to be learned in the school of experience.
]"Samuel Smiles"
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Re: 1/144 scratch build Akula

Postby Vepr » Wed Jun 26, 2013 11:53 am

Bart,

Here's a drawing of the Akula's masts:
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The starboard attack periscope PZKE-11/21 Lebed’
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The radar/ECM mast MRKP-58 Radian (NATO Snoop Pair)
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The satellite communications mast Kora (NATO Pert Spring)
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And here are some good pictures of the Akula's sail with all the masts extended (the second is the K-152 Nerpa/INS Chakra)
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Hope these help

Jacob
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Re: 1/144 scratch build Akula

Postby bwi » Wed Jun 26, 2013 2:44 pm

Thks a lot Jacob….it certainly helps.
Grtz,
Bart
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Re: 1/144 scratch build Akula

Postby bwi » Wed Aug 07, 2013 3:30 pm

Gents,

Another update, despite the almost 4 weeks of vacation, I spent not so much time of it on the “to be fish”. It is an exceptional summer here in Belgium with temps up to 36°C (almost 97°F), so I moved my workplace from the basement to the garden. A much better environment to sand and to apply paint.

The first thing I have tackled are the bumps, gaps and scratched that showed on the master halves in the daylight, and were not revealed by the fluorescent light in the basement, using automotive spray-on putty and filler. With the present temperatures the time this stuff hardens is pretty short too.
During this job I noted the upper and lower halve of the master didn’t pair as well as I would like, I did sand them on a flat piece of wood though. So I went to check and ascertained that the table itself was sagging slightly :(

I tried to figure out how to rectify the master halves. First I straightened out the table. A sheet of styrene on the table served as a nice smooth surface to work on. Next I applied some EUREKA putty all around the edge of the lower master halve, pressed the flat side of the master halve onto the styrene sheet and removed the excess putty that had squeezed out (and hoped it would not stick to hard)……which it didn’t, nevertheless iwo the putty I noted the styrene was affected/melted by the putty, so I was lucky :D . Next step I sanded the flat surface till I was happy with it.

As I did not want to try my luck a second time I tried an other approach. I applied some transparent tape on the flat side of the lower halve and removed the tape that protruded from the contours of the master. Then applied some EUREKAa putty all around the flat edge of the upper halve and pressed both halves together, removed the putty that had squeezed out…..and hoped I could part them after the putty dried…..which I managed :D .
Picture showing the transparent tape in place on the PS, Sb tape already removed, remnants of putty clearly visible on the tape.

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This one showing the applied putty on the upper part.

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I was very happy with the result, both halves are now mating pretty good, picture below, edges still rough but no gap.

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The edges were touched up with spray putty and filler and sanded.
Also I have spent a lot of time to get the trailing edge of the sail right iwo the connection to the deck. The same goes for the corner where the sail mates with the flat deck area. I have put a lot of effort into it in order to get the PS and SB identical (especially in the point where this corner stops and flows over in the curved transition between sail and deck). It is really worth the effort.
Work in progress.

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Next step was applying several coats of automotive primer to the masters and preparing them for molding. The masters in the picture below were wet sanded with 600 and finally with 1200 gri sandpaper.

Close-up sail trailing edge finished.

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Close-up sail corner with flat deck.

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Close-up view of the seam.

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General view after sanding with the 1200 grit.

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Next step will be making the mold board, purchasing polyester, making the molds (this will be the first time that I will work with polyester & Fibreglass, keep fingers crossed) and probably I will make a DIY vacuum chamber so I can start to make the silicone molds to cast the planes, rudders, water intake scoops and SOCKS sensors.

So far this contribution …..I will update this thread when I made some further progress (bad or good).

Grtz,
Bart
Practical wisdom is only to be learned in the school of experience.
]"Samuel Smiles"
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Re: 1/144 scratch build Akula

Postby bwi » Fri Nov 01, 2013 7:41 pm

Hi gents,

Some time has passed but here is the update.
I have made the mold boards out of laminated hardboard; I have reinforced it by means of a longitudinal piece of the same hardboard.

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Moldboard with contours in pencil

The masters were prepared, polishing with automotive polish several times until one could use them as an mirror. Next I have applied the release wax, 5 coats in total, polishing the masters between the coats. Finally I have applied the release liquid with a soft cloth. The masters were ready to receive the gel coat.

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The master were presented to the mold board and the contours were copied to the mold board by pencil. I was pondering about how to attach the master to the board. In first wanted the use screws but let the idea go. Finally I have opted to use some special modeling clay, when it is heated (microwave) the stuff becomes really soft almost in a liquid state. My intention was to heat the modeling clay, make a string, apply the string on the molding board following the contours in pencil, then to press the masters onto the molding board squeezing the modeling clay. I had to make another approach because the moment the modeling clay made contact with de cold board the clay hardened and could not be squeezed anymore. So finally I made thin strings of modeling clay, laid it on the molding board on the contours and heated the stuff up with a paint stripper until it became really soft then pressed the master on the molding boards. The modeling clay squeezed out nicely and the after it was cured the masters were perfectly attached to the board. The excess of the clay was cut away leaving an nice seem between the board and the masters.

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Seem between master and board

To make the molds I have purchased two 2 m² of 150gr glassfibre cloth, 1 kg of gel coat, 2kg of polyester resin, release wax and release liquid.
I had also purchased an good quality half face reusable respirator with adequate filter elements to protect myself against the nice vapor of the polyester resins.
Now everything was ready to apply the gel coat…..it was really strange to cover the nice and shiny master with the gel coat logically one expect this will turn out really bad 
I laid down two coats of gel coat with the necessary curing time in-between, then applied the polyester resin with the cloth. After the last coat was applied on the 2nd master I started to clean up everything. It has been a long day, started at 8h00 and finished at 22h00. When I picked up the measurement can for the hardener my hart jumped over a few times I noted the hardener of the last coat was still in the can…..After some nice vocabulary that lasted several minutes I took the decision to apply pure hardener with a brush on the last coat of resin and hoped for the best.
The next day (very early in the morning) I rushed to the garage to see if my attempt to rectify my stupid mistake worked. I was surprised to see that it had worked quite well, only some miner spots on the 2nd master mold were not cured.

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Gel coat applied

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I left the everything cure further fore Five days, then I tried to extract the masters out of the molds. At first I thought that everything was clued to each other I could not remove the masters, but with some gently applied force (read: red face, pumping veins) I managed to removed them. I was a little disappointed to see that pieces of the master remained in the mold, what went wrong?
I place the whole in my boot and drove to the Polyester store for advice. First of all he told me that for a first mold it was a very good result, I told him I did everything by the book. He suspected that de automotive paint did not cope with the resin of the polyester as it is an one component paint.
After the molds were cleaned and the pieces of the master removed (gently sanded), I was pleased with the result. But the clueing of the master to the mold kept crossing my mind. The paint is protected by the wax and I had applied 5 layers? I applied a layer of wax on a undamaged part of the master and polished it as I did before. I inspected the surface of the master and found it was shining but could not find any trace of the wax, I had polished so hard that I had removed the wax! Now I had found what I have done wrong. This lesson I will remember when waxing the molds.
What I also noted on my molds is traces (brush marks) of the release liquid, even though I used a cloth to apply the liquid. So for making the actual hulls I will spray the release liquid to the molds. But I did not have an air compressor (it was still on my which list).

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Damage to the masters

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Molds after cleaning

As my workshop is in the basement of the house an regular compressor was not an option due to the noise it would create keeping the children awake. I now have an silent air compressor that has also the possibility to hook up a vacuum pot.

I’m waiting for the paintbrush I ordered through the internet and then I will start to make the actual hulls. Meanwhile I can make the vacuum pot to place on top the compressor and connect it to one of the two available suction lines of the compressor.

That’s it for now…… see you next update.

Grtz,
Bart
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]"Samuel Smiles"
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Re: 1/144 scratch build Akula

Postby the dark knight » Fri Nov 01, 2013 7:54 pm

Very cool! I am not sure how I missed this thread! Akula is one of my favorite Russian subs. After the Delta IV and Alfa.
Life is a matter of luck, and the odds in favor of success are no way enhanced by extreme caution. - Erich Topp

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Re: 1/144 scratch build Akula

Postby Sub culture » Sun Nov 03, 2013 9:57 am

You can use hairspray in combination with wax as a release. That comes in aerosol form.

Brush marks tend to be caused by an over thick application of PVA, plus maybe accelerated drying.

However I find I always have to rub down the surface of any GRP laminate before painting, so a few marks aren't the end of the world.
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Re: 1/144 scratch build Akula

Postby bwi » Wed Dec 25, 2013 9:52 am

Hi Gents,

Another update…….as I’m still waiting for my paintbrush to drop in the mailbox so the mold is waiting in the garage for the next step.
Meanwhile the vacuum tank is in progress but I wanted to do some work on the sub.

I’m familiar with propellers in real life but I never have seen a submarine prop in real time, just on pictures. I thought this would be a nice side project to build a subprop in 1/144 scale.

I wanted some more information on the pitch and the diameter of the submarine propellers. I knew there must be something about propellers in the SCR’s. I when through the library of the old SCR’s and found some very interesting articles about the subject.

Issue 9 page 15, The engine room by Robert Hughes and friends
Issue 11 page 66, model submarine propeller theory, design, and fabrication by David Merriman
Issue 19 page 24, yet another way to make propellers by David Merriman.

I studied the pictures I have of the props, it is really hard to tell the exact shape of the blade area as the angle in which the picture was taken deforms the shape of the blade. I had one good picture almost taken at the height of the hub. I have imported the picture in google sketchup and traced the blade shape, that was one les worry. The blade area turned out to be 70% what was ok (see articles).

I decided not to cast the propeller but to make the propeller out of brass. The prop will be diameter 43mm. The 7 blades were cut out a 1mm (0,039") thick brass sheet. The hub, diameter 10mm (0,39") with a length of 21mm (0.82"), was turned on the lathe.

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In order to make the 7 cuts in the hub that retain the blades I made a division aide, a circle was cut out of plywood, the disk was divided into 7; and 7 holes were drilled; in the center I have mounted the chuck of my lathe. A support was made from plywood all glued together. The vertical part was also provided with a hole at the same radius as of the plywood disk. The disk is connected to the support and rotates on it by means of a 10mm axel. When I put the brass hub in the drill chuck I can rotate the circle plate until the next hole mates with the hole in the support, put a taper pin in it and mill the first sleeve in the hub. For the next sleeve I rotate the circle plate until the next hole matches with the hole in the support….I did this 7 times and it worked fine. Before you start milling the sleeves you have to calculate the blade angle at the blade root as per mentioned SCR articles.

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I was in doubt for a long time about the diameter of the hub 10 or 8mm (0,39" or 0,31"), as I had to do a test with the jig I used a 8mm piece of wood; the test was ok but the 8mm was to small compared with the blade dimensions.

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The sleeves are 1mm wide and 8mm in length.

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Next step was to twist the blades in order to get the desired blade angle at a given radius. I had already calculated the angle at the blade root and now I had to calculate the angle at the blade tip. I twisted the blade tip matching the desired angle making sure that the twist is equally over the entire blade length.

The Russian subprops have a attenuator on in front of the hub. To cut sleeves in the hub I used a jigsaw; the blade thickness was 0.4mm. It took some patience and determination to cut the sleeves in the 10mm thick brass but it turned out fine. The attenuator plates ware cut out 0.4mm (0,016") thick brass sheet. One of them was cut longitudinal in halve.

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The hub was cut to length on the lathe leaving a collar at the back. A M4 thread was taped into the hub. My intention is to adjust the diameter of the collar to the diameter of the actual stern-tube collar.
That is the reason I will not solder the prop together yet, if I do I can’t adjust the collar diameter on the lathe.
All part were cleaned up and polished.

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But I could not wait till then to actual see the prop all together so I filled the blade sleeves of the hub with some modeling clay and pushed the blades in place, and all the effort played off with the view I got; a 43mm (1.7 ") subprop.

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Grtz,
Bart
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]"Samuel Smiles"
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Re: 1/144 scratch build Akula

Postby salmon » Wed Dec 25, 2013 12:57 pm

Bart,
Very informative. Thank you.
I appreciate you documenting your mistakes as well as your successes and your successes are fantastic. The prop turned out so well, you make me feel like I could do that......someday.
Peace,
Tom
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Re: 1/144 scratch build Akula

Postby bwi » Mon Dec 30, 2013 6:18 pm

Hello gents,

I finally started to make the upper and lower hulls.

As it is wintertime over here I turned the garage into a artificial tropical greenhouse using an electric heater. The temperature is a constant 20°C, exact what is needed to work with fiberglass resin.
I waxed the molds (this time I didn’t polish the wax off :D ) and used 1 coat of PVA release agent. I applied 2 layers of gelcoat (with grey pigment) and 2 layers of 300 g/m² fiberglass cloth.
Waited two days to let everything cure.

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The hull parted very easily from the mold this time, no gluing at all.
The hull stiffness is OK and so is the weight.

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My first DIY hull is a fact! I’m very pleased with the result.

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That's it for now and probably this year.
For all of you a healthy 2014!

Grtz,
Bart
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]"Samuel Smiles"
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Re: 1/144 scratch build Akula

Postby bwi » Sat Jan 11, 2014 12:54 pm

Another update,

Both hull parts were trimmed with dremel cutoff disks. The hull parts were sanded on a flat surface to make them fit together as good as possible. This worked out fine. I have only a gap (1mm) that I have to rectify. Hull part were wet sanded with 1200 grid paper (surface is to smooth to draw on it by pencil).

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Next thing to do was to cut the lower hull in 3 pieces, quite an terrifying thought after all that work. First I had to determine were I would make the cuts, for the Fwd my first idea was to make the cut iwo the front of the side sonar area, but this was too far to the aft, I would run into trouble to get the WTC into place. So I decided to make the cut at the Aft of the sonar area at the bow.
The Aft cut I decided to make just in front were the tail fins ended. The centerline en cut lines were established by a laser (If you rebuild your house you remain with nice leftovers for your hobby afterwards).

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Before the lower hull was cut I prepared the index lips needed at the sections afterwards. I made the index lips out of polyester resin and 2 layers of 300gr fibreglass cloth. I took over Davit Merrimen’s idea to make them the way I did. First I attached some wax paper to the hull i.w.o. the indicated cut lines. On top I laid-up the fibreglass so the hull shape is exactly transited to the fibreglass. After curing the wax paper was removed and after trimming the fiberglass, you remain with very nice and easy to install index lips.

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As I didn’t had a clue where to find the waxpaper and I did not want to spent half a day looking for it in nearby shops, I shut down all my vital body functions and used that brain cell to pounder if I could use something else. And yes it worked, I think everybody has la label paper roll somewhere in house, well I thought if the labels don’ t stick to the paper is must be some kidt of waxpaper, I remove a label and tested it out with a drop of CA adhesive and it worked, after curing the drop could easily be peeled off the paper.

The cuts were made using my Scroll Saw, five minutes of concentration a the job was done.

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That’s it for now,
Grtz,
Bart
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]"Samuel Smiles"
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Re: 1/144 scratch build Akula

Postby bwi » Mon Mar 24, 2014 4:36 pm

Hi,

It has been a while but my attention was also drawn to the kids…..it isn’t sufficient anymore to just read a book and write a book report……nowadays you have to make an 3D view box, captioning the theme of the book. What does it practically mean…..the children read the book and the parents make the 3D view box :? . For me it was fun doing, teaching the kids to saw, sand and the principle of electrics……yes we went completely over the top with installing some LED’s for lighting inside the box…….but I can imagine some parents had a hard time.

Back to the sub:

The bow and stern were assembled and tagged with CA glue. The middle piece was try fitted. After that the bow and stern were permanently attached with CA glue the seam was reinforced from the inside with fiberglass cloth and polyester resin.
The Fwd and aft index lips were glued in place with epoxy glue.

PS & SB index lips were constructed the same as the Fwd an aft lips, all glued in place with epoxy glue.

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At first I glued the indexes to the upper part of the hull, it turned out to be an bad idea. It was impossible to get de seam of the upper end lower hull nice in line due to the fact that the thickness of the hull halves differed. I removed the indexes (nice job when all is glued with epoxy) made new indexes cut them in 3cm long (1”) pieces en glued them alternating to the upper and lower hull. It took me some time but eventually I managed the get hulls lined up nicely.

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For the propeller shaft assembly I used the techniques of David Merriman.
The propeller shaft bushings in sinter bronze were ordered and arrived. A dummy caliber was turned at the diameter of the bushings. The dummy was centered in the stern. The fish was placed vertical. Polyester resin was poured into the stern the excess was able to drain trough a previous drilled hole. After the resin had cured the caliber was removed.

As earlier stated the stern did not fit perfectly together, I closed the seam with CA glue in order to pour the resin in without leaking through the seam. However the gap resulted that the aft part of the stern was not cylindrical anymore but more of an oval. This could not be rectified until the stern was filed up with the resin. I spent a lot of time to make things cylindrical again and at the same time match the diameter of the bushing.

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The diameter of the collar on the prop hub was adjusted to match the diameter of the stern-tube bushing. In order to solder the prop, a solder jig was made as per Robert Hughes example. I have made mine from aluminum. The seven posts (dia10 x 25mm) are mounted to the baseplate by M4 bolts. A 4mm hole is made in the posts to support the arms, a set screw allows the arms to be fixate into the posts. At the end of the arms a modified screw terminal block is attached, the grinded V-slot can receive the blade, the blade can be fixated by the small screw.

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In between I have finished my vacuum pot, it is combined with my compressor meaning that I can deviate the suction of the compressor to the tank and create a vacuum that is sufficient to deaerate the silicone mold casting resin.

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I have spent some time to figure out the electronics needed for propulsion, I wanted the fish to have an direct drive so following was purchased and arrived as goodies :D :D :D .

• Motor: ROXXY® BL-Outrunner C35-29 500kv, 11.1 V
• Speed Controller: ROXXY 930 8629
• ROXXY Programmer for speed controller V2 8642
• Shaft Sealing Ring 4-11-6 for shaft 4mm
• Receiver Schulze alpha-8.40w 40MHz

I made a support for the motor to try out the configuration, spent almost 1hr to figure out how to change the mode on the speed controller form AIR into BOAT en yes I "RTFM" …….the only conclusion……. you’re getting old Bart :shock: . The generated torque is surprising high for a small motor (dia 32mm, 1 1/4 inch), I’m confident this configuration will work fine.

Next “to do” items:
• Soldering the prop
• Draw all the hatches & flood holes on the hull.
• Cast the dive planes and rudders

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

Re: 1/144 scratch build Akula

Postby bwi » Fri Apr 25, 2014 7:37 pm

Another update,

Soldering the prop:

I used solder with a flux core. This didn’t work at all, the solder did not flow nicely, as a matter in fact it didn’t flow at all resulting in a prop with clumps of solder sticking to it and to complete it all…..blades eventually popped out of the sleeves in the hub. I was so disappointed that I left the prop on the workbench for a couple of days. It looked really bad some of the blade were still not attached even with all that solder clumps sticking to the hub. When all the dust settled down the prop got my attention again. I decided to heat the lump of solder and retrieve all the parts and investigate if any of the prop parts were salvageable. I spent a couple of hours to clean all the blades, attenuator and the hub. The sleeves in the hub was the most difficult to clean, I did it by heating the hub and blow everything out with air pressure. Yes I worn safety goggles but I hope nobody has do the same as I explain below how I manage to solder the prop the right way :D .

To my relieve all the parts were reusable.

I streamed the www and found out that the appliance of a separate flux was the way to go, just as you do with hard soldering (go figure……I have done my part of hard soldering when I was at sea). What I also learned is that some of the fluxes contain acid others don’t. You have to use the one without acid. I ordered my flux on the www and waited……until it dropped in the mailbox.

I prepared the prop in the gig and went to work, applied the flux to all parts, heat everything up and applied the solder (as you have a separate flux you must not use solder with flux but just common solder) and YES YES YES it flowed soooo nicely. I almost say it’s worthwhile the disappointment of the first attempt (but I suggest you skip the first attempt even though the happiness might be less intense :wink: ).

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Stern bushing:

I made a grinding device to get the stern plane perpendicular to the longitudinal axis of the sub doing so I get a perfect fit with the stern tube bushing. The dummy caliber for casting the stern tube was converted to a grinding jig, adding a washer with sandpaper glued to it. Insert the gig into the sterntube and twist it around and you get a perfect mating surface for the bushing.

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Cast the dive planes and rudders:

When I took the planes, rudders and pod and presented them to the hull they seemed out of scale. I remembered that I drew them myself taking pictures as a reference as the shapes of the parts on the Greg Sharpe drawing differed from the pictures. Now they look to big. I shortened (halve an inch) and narrowed them down (1/4 inch) to match the scale.

As the silicone is quite expensive I did not want to waste it in oversize boxes so I tailor-made some boxes out of styrene. The dimensions are slightly larger than the dimensions of the part to cast. The top of the lower part of the box is also the dividing line of the part. It makes it easier to remove the modeling clay excess when you press the part in it. The boxes are provided with two holes for respectively the vent and pouring channel. The lid slides over the lower part.
For the rudder and dive planes this will be an intermediate casting. I have made both out of oak and I’m feel not comfortable to saw the control surface out of the masters, I’m afraid the trailing edges will brake (they are quite thin). So I will first make a cast out of the masters and then saw the control faces out of the cast (if I screw up I only have to cast a new one). Afterwards I will make another cast of the finished pieces. The water intake scoop and the towed area pod will be cast directly into a finished product. The pod I will try to cast as an hollow piece, have to stream the www on how to do it. My idea is not to fill the mold entirely and keep it turning till the resin settles.

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Draw all the hatched, flood holes on the hull:

Still outstanding, I keep pushing this fwd as I’m not yet figured out on how to do it on the bow, probably I will make a template of the bow in polyester to act as an stencil, not sure yet. Will I make just holes in the hull as flood ports or will I make etched flood ports, decisions decisions….. :?

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

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