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Scratch Build Soviet Project 667 BDRM Delta IV SSBN K-18 "Karelia" Scale 1/140

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  • #16
    Nighty mice done, david.does the rudder represent the final product or is it just a mockup? Cannot see a hole for the axis. By the way, what do you do with your master models after finishing a kit? Do you put them on a shelf or so?
    Jörg
    Last edited by JHapprich; 01-05-2019, 07:24 AM.

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    • #17
      Hello Jorg,

      Thanks mate, I do appreciate the feedback. No one else is. I keep all the masters, because you never know if you may need to remould from them again. I found this was the case with the Resolution class as I remoulded its hull 3 times to try and get right. It was by far the hardest boat I have ever done in terms of subtle detail and the complete lack of information on it. Steve Pryce who is doing Repulse over in the UK has said the same thing. I had the opportunity back in '17 to visit him in Birmingham and see his master. It is fantastic..
      The masters take a bit of a beating. Sometimes I have to yank them out of the moulds and Papa's broke in two! I'll send some picks of the carnage...

      Anyway back to 667.

      So with the overall shape of the stern looking pretty good. it meant a lot of sanding, sanding, sanding. Filling in undulations and re sanding. In the meantime just checking that the two booms are symmetrical, identical and angle out the same amount of degrees as needed. Making sure that when you look from the side that you get the same profile running down the stern of the boat. After a good session of sanding I would re-establish the overall lines of the wood blocks. These give really good profile lines that once again give you a good idea of the overall symmetry and surface of the hull. If these hull cross sections deviate too much from each other, you either have to add more filler or sand more filler. Looking along the back end I am amazed at how even and consistent the overall shape is this early..


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      So as can be seen from the last picture I have also been busy on the small parts printing side of things. I have probably printed about 2-3 versions of most parts by now. The printer I am using is doing a reasonable job however It has been difficult to get the sizing exactly right and to some extent I have had to guess until hit upon the right size. It has also allowed me to prototype parts, check fit and durability of things such as hinges and the like them re-design and then re-print. I have also cut out the profiles for the missile deck. This will be built mainly out of plywood and then strips fo timber. It will then on the top be given a strip of Ren shape that will hold all the detail of the missile deck doors.

      The top rudder section will actually be slightly reduced in size from the one seen here. It I will not be printing out the base but will do this in Renshape. The actual parts will slot in as is my custom to a recess that will feature on the top surface of the raised profile fillet that will appear on the upper stern hull between the booms.


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      I couldn't resist getting the basic mock up happening as rough as it is. It gives an idea of the size and overall proportion of this boat. It certainly has plenty of character. As mentioned previously the screws need a lot of work, you can still see layers on them and some small bits of filler that will need to be smoothed off. I drilled and placed some 4mm threaded rod in the two stern booms to get an idea of how the screws will look. I'm pretty happy so far. You need some really fine tools to get into the crevices and irregular curves in these blades. Hours of work ahead...




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      The next area that I decided to look at was the stern planes. I have invested a fair amount of energy designing and redesigning the stern planes and have found some discrepancies between them. For such a large boat they are really quite small, however this seems to be a very Russian thing...


      Anyway enough for now, I think that I have scared off HWSNBN...
      Please feel free to comment and give advice. Always interested to know what people think...

      David h









































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      • #18
        Hey david, this is what i noticed
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        Regards, Jörg

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        • #19
          Maybe you could shine a laser level light on it to check symmetry.
          Would be nice to have a machine like this to rough out the shape.

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          • #20
            Thanks Jorg, Scott T .

            will have a good look at stern and address those issues...

            Dave.

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            • #21
              I have always had a soft spot for the Delta IV and am watching this progress with great interest.

              You definitely know your way around 3D printing, and it looks like you are putting it to fantastic use. I am curious how you deal with the stirations on the surface. I have always had mixed results getting the surface of 3D printed material to look smooth like polystyrene or resin.

              -Brady

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              • #22
                Thanks Brady,

                Thanks for the comments, I’m pretty happy with how she’s looking so far...

                As an Industrial arts high school teacher I have been doing a lot of 3D printing. I get to take the school ones home to practice and ‘get to know the technology’.

                As for hiding the layers I use an automotive spray putty.

                https://www.ritepricedistributors.co...EaAkDpEALw_wcB


                you should be able to find a US equivalent. Spray on sand back ,spray on sand back, spray on......... finer and finer set and dry after about six-seven coats it looks really good.

                David H

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                • #23
                  Hello all,

                  As pointed out by Jorg one side in particular was not as straight down the side as it could have been. I have once again taken to the filler and a ruler and dragged the edge of the ruler over the radius of the side and made the filler smooth over the subtle parts that created the undulation that was causing offence. I have also taken with a file to the radius on the inside of the booms to just get them even.

                  I have actually spent a fair amount of time going over the symmetry of the twin booms. If I don't get this right there will be problems. I have also sanded back further area where there are inconsistencies around hull frames as seen from the stern looking forward. Once this was done I needed to check alignment for the back end. I have been thinking for some time about how to get a twin boom to rotate and to secure the wedge shaped middle in between the booms in such as way as to make it secure without damaging the rear end. I simple decided that with what I needed to do I would not at the moment need to rotate the stern section. So I decided to have it rest on the base and create a two pin connection with nails going into the twin booms and the forward section sitting level on the base. I just needed to work out my equators and vertical axis line. This would allow me to make a start on the horizontal stern planes.


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                  The 667's stern planes are quite small in comparison to the rest of the boat. They also feature these vertical fence like panels. They remind me of the wing fences on the MiG 15-21. At first when I printed these out they were so brittle and weak that they simply broke of when pulling the surface off the printer platform. If they did survive the removal process then they were bent or not of constant thickness so I simply decided to do away with them and I'll create styrene ones later that will be more hardy and consistent thickness. I will them need to think about how to arrange them the best way for the silicon mould making process a couple of months down the track. I have also taken a liberty off scale by adding a very small round hinge section as I cannot see how the rotating shaft is secured towards the tops of the stern planes. It's all covered over and hidden mainly behind the vertical plates.



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                  I would also have to make sure that the outer panel /fence would be angled in slightly towards the trailing edge. Can anyone give me the details on whys some Russian boats have these vertical plates on the stern planes? Both vertical and horizontal. I would be really interested to know.
                  So moving on the alignment. I made a small block of particle boat and accurately measured and drilled two holes along a horizontal line to mark and secure the twin booms. The height of the line above the base needed to be exactly the right height so the rest of the hull would sit dead level. At this point they have been drilled out and have a 4mm thread in them that I have used to screws the propeller on to check for accuracy and how the boat is going to look. (I frequently put everything together just to get a feel of its overall looks and proportions. This make me feel like I'm getting somewhere! ) Once this was done the stern section could be fitted on and should have the equator lines be exactly the same height off either side of the board. This would allow me to then scribe an accurate horizontal line along the length and help me work out the placement of the stern planes. This would allow me to accurately measure the distance to the trailing edges and leading edge of the fillet profile. It would also allow me to accurately mark upwards abive the equator to establish the centreline for the stern planes since on Russian boats this is above the overall centreline. (something I was only aware of towards the very end of the Papa build, thanks Jorg and HWSNBN!)

                  Once this was done I could mark out the exact spot that would be the location of the stern rotating shafts and drill a hole for them. This is always tricky as it means drilling holes from either side and making sure they line up. Sure it can be a dogs breakfast inside the hull however you do not want to come out anywhere other than the opposite hole you have just created. Tricky also because my drill bits are not long enough to go all the was through.







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                  As you can see the parts are quite rough, however they will slowly get polished. It's all about getting the alignment right and everything square.
                  Once again any comments or recommendations would be great.

                  Off to bed. Try and get to sleep in this humidity. It's still 28 degrees!..

                  David H


























































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                  • #24
                    Maybe those plates on the planes prevent the towed array from beeing stuck in between. Or they protect the rudders for under-ice ops. Typhoon has those, too (but lacks a towed sonar...)

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                    • #25
                      Originally posted by JHapprich View Post
                      Maybe those plates on the planes prevent the towed array from beeing stuck in between. Or they protect the rudders for under-ice ops. Typhoon has those, too (but lacks a towed sonar...)
                      They serve like wing-fences or vortex-tips on an aircraft. On the submarine, the function of these appendages is to prevent water from sneaking up and around the ends of the planes from one face to the other when deflected to the water flow. Control surface deflection to the water flow produces a differential pressure between the two faces of the control surface -- its that differential which produces the force (lift, if you will) that pitches/yaws the submarine about its c.g.

                      David
                      "... well, that takes care of Jorgenson's theory!"

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                      • #26
                        Originally posted by He Who Shall Not Be Named View Post

                        They serve like wing-fences or vortex-tips on an aircraft. On the submarine, the function of these appendages is to prevent water from sneaking up and around the ends of the planes from one face to the other when deflected to the water flow. Control surface deflection to the water flow produces a differential pressure between the two faces of the control surface -- its that differential which produces the force (lift, if you will) that pitches/yaws the submarine about its c.g.

                        David
                        That’s interesting. I was having a conversation with my dad (who is a pilot) not too long ago, and we got to talking about how aerodynamics & hydrodynamics are similar in so many ways, but then not at all in others given the difference in density and properties of water vs. air.

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                        • #27
                          Originally posted by DMTNT View Post

                          That’s interesting. I was having a conversation with my dad (who is a pilot) not too long ago, and we got to talking about how aerodynamics & hydrodynamics are similar in so many ways, but then not at all in others given the difference in density and properties of water vs. air.
                          The significant variance between the two fluids is the compressibility of a gas (air) and incompressibility of a liquid (water). A propeller in water can cavitate. A propeller in air can go super-sonic. Two situations that affect propeller performance. But, by and large, the two fluids are fair analogs -- that's why you sometimes see a submarine model in a wind-tunnel. Reynolds Number will correct for geometry and viscosity.

                          David
                          "... well, that takes care of Jorgenson's theory!"

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