Akula 1/144 Scratch built

[He Who Shall Not Be Named]

I postponed this one for a long time, kept pushing it fwd. But I have to do it sooner or later.
I never have done this but there were plenty things I had never done before this build with fail and error.

In preparation to the scribing I have to draw every single hatch, hole,….onto the hull. I have seen this done by his eminence back then, he made some kind of jig that holds the boat and it enables it to turn around freely, it works like a lathe.

Making all these jigs is time consuming so when I do it I use good solid materials so I can reuse them for later projects.

The molding board that I made previous was used as the base structure. On top two post were placed. The post have some horizontal travel so the hull can be placed in-between, this was managed with a slotted baseplate. I have designed the base of the post in such way that they do not protrude the perpendiculars of the hull, else the would get in the way when drawing.

[ATTACH=CONFIG]31306[/ATTACH]

The sterntube is used to connect the stern to the aft post by means of a 4mm diameter shaft, the aft post is provided with a bushing (inner diameter 4mm outer 8mm with collar).

[ATTACH=CONFIG]31307[/ATTACH]

As I didn’t(t want to drill a hole in the bow I came up with a hollow disk that would take the curved bow. I provided the disk with an o-ring in order to get enough friction between the disk and the bow. The disk is also be provided with a bushing, and same goes for the Fwd post. A dia 4mm rod is connecting the disk with the post.

[ATTACH=CONFIG]31308[/ATTACH] [ATTACH=CONFIG]31309[/ATTACH] [ATTACH=CONFIG]31310[/ATTACH] [ATTACH=CONFIG]31311[/ATTACH]

All the a.m. parts were fabricated and installed to the molding board. The hull was presented to the jig and it turned out very well, no hiccups.

In order to get a nice perpendicular movement from the marker with the hull I also fabricated a movable guide that can be tighten to the base (moulding board).

[ATTACH=CONFIG]31312[/ATTACH]

As I finished that I also made the post that retained the marker, the post is also provided with slots for the up and down movement.

[ATTACH=CONFIG]31313[/ATTACH] [ATTACH=CONFIG]31314[/ATTACH] [ATTACH=CONFIG]31315[/ATTACH] [ATTACH=CONFIG]31316[/ATTACH] [ATTACH=CONFIG]31317[/ATTACH]

the assembly

[ATTACH=CONFIG]31318[/ATTACH] [ATTACH=CONFIG]31319[/ATTACH] [ATTACH=CONFIG]31320[/ATTACH] [ATTACH=CONFIG]31321[/ATTACH]

Did the hollow disk work? NO IT DIDN'T. It will only work if you have a perfect spherical bow. Else you will never achieve to center it, and believe me I have tried.
So I drilled a 4mm hole in the bow, but as I’m very stubborn I kept the o-ring (ok it's smaller but it is there).......it's a tie ms Akula EAT THAT.

[ATTACH=CONFIG]31322[/ATTACH]

grtz,
Bart

Good stuff, Bart! For those wondering how I did mine:



M

[bwi 971]

That is well thought out David....you can adjust your inclination that comes in handy, I have to shim mine out if needed. I will adapt that before I start my next project. I try to focus the brain to finish this one first.

Grtz,
Bart

[bwi 971]

HI BART ,


Unfortunately there is NO emoticons to express exactly my face expression !!! .

All I can say is : Please do what You are doing now as often as You can , on as Manny models You can .
Is a pleasure and a thrill to see what's comes up from Your hands .

THANK YOU for sharing .

MARIUS

THKS Marius….. but that's too much credit…….I'm just put to practice what I have learned from others, sometimes adding ideas & tweaks, some work many don't.....Ideas that work we take over from others but we must not forget that it takes many ideas to get the one that works.

That’s why I have so much respect for anybody who is into this hobby especially those with limited means because they have to be the most inventive to get things done and came up with the most brilliant ideas. Maybe some of mine can help others, that’s why I post this stuff.

OK must get some sleep now....I start to sound like some kind of “hobby preacher man”…..can be the acetone vapors to…. or has the wife actually came home with a pink elephant?

Grtz,
Bart

[Von Hilde]

THKS Marius….. but that's too much credit…….I'm just put to practice what I have learned from others, sometimes adding ideas & tweaks, some work many don't.....Ideas that work we take over from others but we must not forget that it takes many ideas to get the one that works.

That’s why I have so much respect for anybody who is into this hobby especially those with limited means because they have to be the most inventive to get things done and came up with the most brilliant ideas. Maybe some of mine can help others, that’s why I post this stuff.

OK must get some sleep now....I start to sound like some kind of “hobby preacher man”…..can be the acetone vapors to…. or has the wife actually came home with a pink elephant?

Grtz,
Bart

Bart, if your wife is looking for a pink elephant, mine has a couple to spare.I need the room to put more boats. Scratch building is becomming a lost art. Not many people want to spend the time, effort, and research, then trial and error, to achieve the desired results. Most just toss money at the problem to have the experience of achieving the goal. This case a working submarine model. For me, the build is the fun part. A scratch built project is easy for me, to tear apart after months of work. If Im not happy with a certain detail or get tired of looking at the finished project, and want to change something, its no big deal to rip it apart and stick it back together. Just more fun time and another challange. I like the look on peoples faces when they see something they like and ask where I got it. I point to the recycle bin, and say I made it, with this that and the other..I'm retired, or semi retired, in my 70s. I still play music and paint, but dont have to go to work all day so I have plenty of time to enjoy the hobby. Unless the "Fishing" equasion interupts the daily grind.

[Von Hilde]

THKS Marius….. but that's too much credit…….I'm just put to practice what I have learned from others, sometimes adding ideas & tweaks, some work many don't.....Ideas that work we take over from others but we must not forget that it takes many ideas to get the one that works.

That’s why I have so much respect for anybody who is into this hobby especially those with limited means because they have to be the most inventive to get things done and came up with the most brilliant ideas. Maybe some of mine can help others, that’s why I post this stuff.

OK must get some sleep now....I start to sound like some kind of “hobby preacher man”…..can be the acetone vapors to…. or has the wife actually came home with a pink elephant?

Grtz,
Bart

Bart, if your wife is looking for a pink elephant, mine has a couple to spare.I need the room to put more boats. Scratch building is becomming a lost art. Not many people want to spend the time, effort, and research, then trial and error, to achieve the desired results. Most just toss money at the problem to have the experience of achieving the goal. This case a working submarine model. For me, the build is the fun part. A scratch built project is easy for me, to tear apart after months of work. If Im not happy with a certain detail or get tired of looking at the finished project, and want to change something, its no big deal to rip it apart and stick it back together. Just more fun time and another challange. I like the look on peoples faces when they see something they like and ask where I got it. I point to the recycle bin, and say I made it, with this that and the other..I'm retired, or semi retired, in my 70s. I still play music and paint, but dont have to go to work all day so I have plenty of time to enjoy the hobby. Unless the "Fishing" equasion interupts the daily grind.

[bwi 971]

WTC and Dive module

Due to wintertime I focused on the internals of the sub. Me, myself and I quickly agreed that DIY was the way we wanted to go. As usual the others left the building and I remained to figure out “how to”. I had to do some drawing as I also wanted to DIY the piston tank.

I took possession over the laptop and searched the www for some free 3D drawing software. But I didn't really find something that made me say eureka.

A former colleague used sketchup to design his house. I previous used it, as a drawing board, to draw some simple things but something complicated as this I had never done. Nevertheless I had a go at it. After I conquered the basics the software was very kind to me (Normally software and myself don’t get along). They have also great tutorials so I quickly (I thought It was quick.....probably it wasn't) learned the tricks of the trade.

I spent a lot of time searching for the dimensions of all the necessary gears, bearings and spindles. Also I spent a lot of attention to calculate the necessary dimensions of the components needed (endcaps, o-ring groves, wall thickness, discharge opening,……). For this I found a lot of information in a booklet of Norbert Brüggen and for the o-ring groves I again used the guidlines of Andrew Lawrence (Sub Culture).

During the process of drawing all the components I decided I wanted one tank with two pistons, both pistons working on one motor. When using a single piston tank, there is a weight shift when the piston moves towards the stem or stern, taking water in or pushing water out. So you need to compensate this. As I want to make a static diver I wanted to minimize this shift so I went for the double piston.

I took over the Idea from the webside of Markus Reidegeld he made several of these tanks. Also the positioning of the servo’s I took over from him.

All this information was transferred to the drawing board. Just one sentence but it took me almost two months to do it but I can now officially state that I have some experience with sketchup. The only disadvantageis that you can’t print isometric so you have to draw everything on a real drawingboard if you need stencils. But is a great tool to design and you know the dimensions your stuff.



you will note that there are six servos drawn but that was just to see how much I could squeeze in, the fwd three will be reduced to one piece the aft three to two pieces.
The length of the pistontank needs to be adapted to the necessary ballast volume I have to take in. It will be less than the 500ml I have drawn now, so room will be available for the battery.
The dimension of the WTC is dia 80mm x 550mm [3” x 22”]. The calculated dive time is 5 sec for 500ml.

Now that looks real nice on paper, didn’t it.

I ordered all the necessary parts. The plexiglass (PMMA) tubing arrived diameter 80mm for the WTC and 50mm for the Pistontank.

As I needed max length (piston tank spindle) the WTC was cut at the max length the boat could take 670mm instead of the initially 550mm. When presented in the boat there was no space to add foam or any other stuff. When I weighted the hull and WTC and calculated the bouncy (with the estimated weights of all bit and pieces) I came to the stunning conclusion the she would sink, there was nothing left and I had no space left to add foam. But I needed the length for the spindles of the piston tanks.

I hit the brick wall hard and was lying on the floor. It was time to reconfigure the ballast system.

Still pondering about the ballast system but I focused to the fabrication of the endcaps. As I only have a small lath I decided to cut disks out of 4mm thick plexiglass. I did the same for the lit for vacuum tank, and it worked well.
You just have to cut one disc smaller in diameter to take the O-ring. Glue everything together and you have a perfect endcap without using a lath.



I have spent quite some time in designing the end caps. Holes for the pushrods and prop shaft are integrated also the alignment for the servos took all of my attention.


Take in mind that drilling holes in plexiglass can be tricky. The drill jammed..... &#%!@?!…...so I had to start all over. Message to myself. DRILL THE HOLES BEFORE YOU GLUE EVERYTHING TOGETHER YOU IDIOT......THAT ARE 4 FT WORKINGDAYS(I forgot to make the holes for the wires, cost me dearly)



I have provided 2 prop shaft seals and two bearings I was a chief engineer on merchant ships so I like redundancy (No Hardware stores @ sea).



I had 6mm holes foreseen where the pushrods protruded the WTC as I couldn’t decide what sealing system I wanted to use. A bellow seems the easiest, but they are fragile and can’t cope with pressure very well, I had to take that into account as I still haven’t made up my mind on the ballast system.

O-rings was the way to go, so I designed a stuffing box, It had to be replaceable. I needed O-rings outside to make the seal with the WTC and inside to make the seal with the pushrod. I have some redundancy build in, two o-rings each. The pushrod will be 1,5mm in diameter.
Here again I used the electronic drawing board. As everything is gonna be so small I had to make it out of 4 sections as it would be impossible to put the inner o-rings in place true the 2mm hole that takes the pushrod.



Time for the prototype. I made the 4 sections separately out of 5mm plexiglass. Why on earth in plexiglass because you can glue it with acetone. And acetone hasn’t any effect on the O-ring (and I had some leftovers). That way I could position the inner O-ring (still on backorder, so it not shown) then glued everything together.
What I did as it is a prototype. Stuffing box dimensions outer diameter is 5,9 something, length 15mm.



I was pondering how to provide the outer groves. The trouble was it hat to be precise and I could not put to much strength on the stuffing box. The bore is 2 mm in diameter and the inner diameter of the grove would be 3,1mm; 0.5mm material remained (0.02 inch).
I came up with this. I use a hand grinder. I made a jig to support my hand grinder. The tool holder of the lath was replaced by this jig. A 1mm diameter cutter was installed in the grinder. The grove dimensions are diameter 3,2mm, wide 1.8mm.



The O-rings were installed and the seal assembly was test fitted in the WTC. Nice tight fit. Mission accomplished. When I receive the inner o-rings I will start production of the 4 stuffing boxes.



Grtz,
Bart

[bassplayer1]

Bart, if your wife is looking for a pink elephant, mine has a couple to spare.I need the room to put more boats. Scratch building is becomming a lost art. Not many people want to spend the time, effort, and research, then trial and error, to achieve the desired results. Most just toss money at the problem to have the experience of achieving the goal. This case a working submarine model. For me, the build is the fun part. A scratch built project is easy for me, to tear apart after months of work. If Im not happy with a certain detail or get tired of looking at the finished project, and want to change something, its no big deal to rip it apart and stick it back together. Just more fun time and another challange. I like the look on peoples faces when they see something they like and ask where I got it. I point to the recycle bin, and say I made it, with this that and the other..I'm retired, or semi retired, in my 70s. I still play music and paint, but dont have to go to work all day so I have plenty of time to enjoy the hobby. Unless the "Fishing" equasion interupts the daily grind.

I couldn't agree more !!!

[bassplayer1]

Great work here Bart, I really enjoy this thread!!!

[Von Hilde]

Excelent idea making your end caps laminated, rather than turning a solid block. I will file that away in my trick bag. Plexiglass is nice looking, but I think I may use sheet PVC. Plexiglass cracks easily when drilled, as you know. PVC is more resilliant and mills up real nice, no chips or cracks. Cheaper too. And it can be welded or vulcanised, chemiclly or heat. Man, I have to get me a small lathe at the bunker. I have to go 3 islands down the Keys to use my buddies shop, to do millwork.

[Von Hilde]

Well, after a couple seconds of dreamig about it, I ordered a small hobby lathe, When the Queen finds out, I'll blame it on Sir Bart. "The Black Knight" Mabe if I take a couple of her wooden spoons and turn spindells on the handles, I can get an approval of justification.

[bwi 971]

Well, after a couple seconds of dreamig about it, I ordered a small hobby lathe, When the Queen finds out, I'll blame it on Sir Bart. "The Black Knight" Mabe if I take a couple of her wooden spoons and turn spindells on the handles, I can get an approval of justification.

Go ahead David I will take the heat.....I which I had done the same ....just finished cleaning the house, next up is the laundry.....5 years to go (but it was worth it).

[Von Hilde]

Go ahead David I will take the heat.....I which I had done the same ....just finished cleaning the house, next up is the laundry.....5 years to go (but it was worth it).

I am thankful, that I manage to get out of laundry. I don't do it correctly, She says. I wash everything at once, her delicate things with my fishing shorts. I did it just one time and I have been forbidden to operate the machinery, for life. Cleaning the house however, is in my realm of job obligations. I make the biggest mess, so, you have to pay, to play.

[HardRock]

Well, after a couple seconds of dreamig about it, I ordered a small hobby lathe, When the Queen finds out, I'll blame it on Sir Bart. "The Black Knight" Mabe if I take a couple of her wooden spoons and turn spindells on the handles, I can get an approval of justification.

Carpe Diem Mate!

[Von Hilde]

Carpe Diem Mate!

Carpe Temporus Punctum-Edo Edi Essum Diem

[bwi 971]

Scribing

I have been doing some test for scribing. I used the needle of a pair of compasses, blunt the point (just a touch). It is ok…….here comes the but part.



The problem is that I have to go to deep to get the desired wideness of the grove. When I try to paint is the paint does not reach the bottom part of the grove. When I tried to scribe with a more blunt tool the grove looks like sh*t.
So I wanted to post here a question how to do it but then I hit the search button of the forum typed “scribing” and the first hit was this.

Scribing stencils, and a pointed needle (re-worked needle-file) is all you need. The trick is to start with the sharp point and to then make the finishing passes with a blunt point with a shank of constant diameter. Practice, practice, practice.
M

It is all on the forum……So I have my starter tool just have to make my finish tool now.

Grtz,
Bart