Author Topic: Rear torpedo section VII / 3D model / 1/72  (Read 31321 times)

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Offline Marko

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Rear torpedo section VII / 3D model / 1/72
« on: 15 Apr , 2012, 17:48 »
hello guys,

i thought it would be wise to split the design into separate topics, to keep the topics more clear. The printing is not yet possible, so i decided to start the rear section with the current standards anyways. currently i am awaiting those big sets of plans from Fritz K
« Last Edit: 13 May , 2012, 09:11 by Marko »

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #1 on: 16 Apr , 2012, 14:25 »
The design proved to be almost correct, here are the results in photos:
the only thing which bothers me, are those three vent holes located on the rear portion of the fuel tank, i have to implement the tanks curvature into it to prevent seein into the pressure hull through those three holes, so back to the board correct that fiddly bit.






TopherVIIC

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Re: Rear torpedo section VII / 3D model /
« Reply #2 on: 16 Apr , 2012, 18:19 »

Marko -
Once more you have a start - and a start is a good thing!
Keep in mind that the aft section, like the forward torpedo section, is actually a couple of tapering conical sections. Picture being inside a cone that is getting smaller as it goes aft. Developing 2-d planar surfaces and rolling them into 3-d physical models will take a little bit of work.
On the drawings, where you see the German word "Knick" it means "Kink" - it is where planar forms are welded together to make offset frustums - cones with their heads whacked off, and axis shifted.
If you are building from the "E-Machine" bulkhead, back, you are dealing with three separate conical sections. Not one of the ceilings will be at 90 degrees like a regular room would have.
In this section, because of the small tapering diameter of the aft conical sections, the internal ribs (DruckSpant) are not all at the normal 600mm spacing. Look closely at the drawing and you will see what I mean.
Also keep in mind that the torpedo compensating tanks in the extreme aft section actually surround the walking space of the working deck (floor) and there was narrow space for a single torpedo stowage belowdeck.
I look forward to seeing what you come up with - and I hope this helps a bit...


Simon's drawings, and this http://www.kubische-panoramen.de/index.php?id_id=5375&p=i are also great!

Christopher
« Last Edit: 16 Apr , 2012, 18:52 by TopherVIIC »

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #3 on: 17 Apr , 2012, 01:43 »
Yep,

the  thing that makes the shapes complicated here is the molding from revell, i tried several combinations of surface creating, and current variant is the closest i can get. Since the revell molded the hull insides as continuous piece (no tapering, i cant do much about it, except of thinning the hull halves, which i would like to avoid as much as possible.

My first attempt was making design directly as per drawings, but i could not get the prototype to fit, too much gaps. The current model fits in 95%, yet i still have to work on it, as mentioned the three flood holes just above the fuel tank are mostly problematic, however this morning i got an idea how to solve it, and will try it as soon as i get home from work. Though bear in mind that this paper model is just prototype with basic shapes, to get the  basic outlines of the design area. I will probably make the section virtually elongated into rear with the partial torpedo tube and components near it half sticking out of the rear bulkhead, then it will be added final solid model of the rear segment of pressure hull, just to get the impression through the flood gates that the hull actually continues. I hope this will be acceptable substitution, since i really would not like to whack up the whole hull up due to esthetics, and also gaps would be difficult to fill in this case.

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #4 on: 18 Apr , 2012, 13:26 »
hello guys,

finally i made it through the last test, and i think i finally nailed it, even better than i expected.
here is the result in photos:






Here is a final version (i think it was Nr. 11) that i unrolled and assembled with paper. The differences between this and the previous variant are in elongated arc of the ceiling to follow the contour of the cut-out in the hull, and the curve that fills in the saddle tank gap from the inside. This way i achieved the effect of continuous pressure hull when seeing in from the three saddle tank flood gates. Also the red lines are guide lines for the PH virtual extension which will be made as solid piece to trick the eye when seeing inside from the rear under flood gates.

Marko

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #5 on: 19 Apr , 2012, 11:04 »
hello,

i have a question, had a spare torpedo in rear torp. room a cylindrical or other type container, or was it only laid in a cradle beneath the torp. room floor?

TopherVIIC

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Re: Rear torpedo section VII / 3D model /
« Reply #6 on: 19 Apr , 2012, 12:56 »
Marko -
It seems to me that a container in the extremely confined aft torpedo room/E-machine space would be extremely unwieldy. A solid tube like the ones stowed below the top decks would not work - no room. A nested container would either have to be hinged the entire length of the container on two sides, or it would have to be a lift off affair. Both cases would involve handling large, ungainly useless pieces of hardware afterwards, all of which would take up more room than would be available. It would also add dead weight that would serve little function.

The drawings I have seen of the forward torp stowage, and photographs show cradles, chocks, and straps, with flimsy deck support to keep the working deck level. I assume the aft torp stowage would be similar.
Just my thoughts - but a good question to ask.
Christopher

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #7 on: 19 Apr , 2012, 17:00 »
It seems to me that a container in the extremely confined aft torpedo room/E-machine space would be extremely unwieldy. A solid tube like the ones stowed below the top decks would not work - no room. A

The drawings I have seen of the forward torp stowage, and photographs show cradles, chocks, and straps, with flimsy deck support to keep the working deck level. I assume the aft torp stowage would be similar.

so was my opinion. well, i did not bother drawing it yet, however i made the floor using drawings that i have + quite a bit recalculations to get proper measures for the 1/72 scale. Im calling it for a day.

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #8 on: 22 Apr , 2012, 14:23 »
hello guys,

well it does not look much progress, but i completed the walls of the compartment, and i finally have inner perimeter where i can draw the interior parts. Also i made the false PH elongation, as seen on the picture:


Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #9 on: 28 Apr , 2012, 05:25 »
took some while, but here is some progress, though still a lot of work on it has to be done :)
this time i am working on it bottom side up, have to complete the torpedo holder and then to the upper section. Feel free to comment it and if i made something wrong, point the issue out and i will try to solve it :-)



Offline tore

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Re: Rear torpedo section VII / 3D model /
« Reply #10 on: 28 Apr , 2012, 08:40 »
Marko
In this area is situated an important part of the submarine which you should try to incoporate, the thrustbearings, which transfer all the power from the propellors to the hull. As such the thrustbearings are mounted on a very strong structure intergrated in the pressurehull. I have posted a picture below indicating the arrangement.
Tore

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #11 on: 28 Apr , 2012, 09:35 »
aha, i noticed those already, and made appropriate holes in the "catwalk" floor - "T" shaped cut out in the floor:

although i am not sure how, or if should i replicate the foundations on the starboard side (cut-out) side of the hull, maybe should i do the foundation only on the port side?


Offline tore

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Re: Rear torpedo section VII / 3D model /
« Reply #12 on: 28 Apr , 2012, 09:51 »
Marko
I don`t know how you are planning the propellorshafts which of course is an intergrated part of the thrustbearing, I guess that would be guiding you how to draw the thrustbearing and foundation. Below is a photo of typical thrustbearing housing ( not 100% VIIC, but will do).
Tore 

Offline Marko

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Re: Rear torpedo section VII / 3D model /
« Reply #13 on: 28 Apr , 2012, 14:53 »
well, another dilemma:
after ribbing has been done, the torpedo intersected with it. currently i made a cradle like form into the ribs, so the torpedo head is laid into the hull on front end too. The only possible way is to shorten the torpedo by 1 good cm, maybe a little bit more. By doing this, this torpedo would be shorter than the others from CMK. im not sure what to do..  i cant lift the torpedo compartment floor since it would have to be lifted for good 3-4 mm which would increase the floor height difference between engine section and torp. room, and i cant afford that drastic change here.. So, should i shorten the torpedo or leave it as is?


Offline tore

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Re: Rear torpedo section VII / 3D model /
« Reply #14 on: 29 Apr , 2012, 00:08 »
Marko
It looks to me the your torpedofront is a little too butt compared to the posted drawing below. May be if you make the shape as on the original drawing it will fit in.
Tore